JPH10230590A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optimum image by regularly forming a mask pattern for generating discharge data of more number of times of discharging at the time of mixedly existing different numbers of times of discharging for number of times of discharging to the same position of a medium to be recorded. SOLUTION: A random pattern is used for a medium to be recorded of a plain sheet mode by haploid or more density. The pattern is set with a mask of the same size as that of a mask data size corresponding to one time scanning (S1), its interior is fully filled with four parameters, a pair of parameters are selected from the parameters in a random numerical manner, substituted plural times to generate mask data disposed at random with the parameters (S2), and previously stored in a ROM. Further, the parameter is, for example, formed with thinned mask corresponding to mask data A to D (S3). The random pattern is not used in density exceeding haploid, but thinned pattern for regularly interpolating with each other is used to record.

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 performing recording by discharging ink from a recording head onto a recording medium, and more particularly, to an arrangement for modulating a recording density realized in a recording medium. It is.

[0002]

2. Description of the Related Art A recording apparatus used in a printer, a copying machine, a facsimile, or the like is configured to record an image composed of a dot pattern on a recording medium such as paper or a thin plastic plate based on image information. ing.

[0003] Such a recording apparatus uses a recording method,
It can be divided into inkjet method, wire dot method, thermal method, laser beam method, etc. In the inkjet method, ink (recording liquid) droplets are ejected from the ejection port of the recording head and fly and adhere to the recording material. The above-mentioned dot is formed.

On the other hand, in recent years, with the general spread of recording apparatuses, various requirements such as high-speed recording, high-resolution recording, high-quality recording, and low-noise recording have been made. It has become to. For such a request,
The above-described ink jet recording apparatus responds relatively well, and in this ink jet recording apparatus, non-contact recording is possible because recording is performed by discharging ink from a recording head, and therefore, very stable recording is performed. Images can be obtained.

[0005] The configuration capable of appropriately performing density modulation of a recorded image is a major factor for high-quality recording required for the above-described recording apparatus. For example, a recording medium has an optimum amount of ink ejection for realizing a certain density according to its type, and therefore, it is necessary to perform density modulation in which the amount of ink ejection is appropriately controlled.

[0006] Further, from the viewpoint of density modulation, there are cases where the user's preference for the recording density varies, and for example, there is a demand to change the setting of the maximum recording density.
In some cases, the maximum recording density may be reduced in order to reduce the ink consumption.

[0007] As one configuration that enables such density modulation, it is known to perform thinning recording and change a gamma curve related to image data processing. However, in a color image, a so-called thinning recording (drafting) is performed. When recording is performed, the tint often changes in the case of halftone due to synchronization with the thinning mask. If a gamma curve having an extremely high rate of change is used, the gradation may be impaired.

For this reason, many conventional configurations use a recording head capable of realizing the required minimum recording density and perform various controls to increase the recording density according to the recording medium and the needs of the user. . For example, a configuration is known in which dot-on-dot printing is performed twice for a specified font, or double-printing is performed by adding a dot between dots, as represented by bold printing. Further, there is also known a method in which only the edge portion of the font is extracted and the printing is performed twice as the edge emphasis in the twice printing.

The configuration for performing the conventional double printing is originally derived from the command system of the wire dot printer, and simply forms approximately twice as many dots as necessary in an ink jet recording apparatus. However, it is not intended to optimize the balance of the necessary coloring properties, maximum density, bleeding, color mixture, etc. by adjusting the amount of ink applied to various recording media. The configuration of twice printing in an ink jet printer having a low maximum density is naturally known. The configuration of these two-time printing is relatively simple from a technical point of view. This is because, in the process of simply increasing the number of dots in the case of printing twice, there is no problem of texture that degrades the image quality in relation to the synchronization with the image data.

As another density changing means, there is known a means for optimizing the recording density on a recording medium by changing the dot system without increasing the number of recording dots by PWM modulation or keeping the recording head warm. The individual methods are relatively effective methods, such as being simple and capable of modulating in dot units, and have recently been diversified as discharge amount modulation methods. However, as a problem when applied to an ink jet system using thermal energy, there is a problem that a modulation range is narrow. For example, the main method of dot modulation uses multiple pulses to eject one dot,
Among these methods, for example, a method of modulating the ejection amount by modulating the preceding pulse, the modulation range is about 130% in a practical range. Also, even if the temperature of the recording head is made higher than the normal use temperature and the viscosity of the ink is used together,
In a practical range, it is about 140%. This is because, if the temperature of the print head is further increased, it takes time to change the temperature. For example, when the type of the recording medium to be used is changed, it is not possible to immediately respond to this. May occur. Further, when the temperature of the recording head is increased beyond the practical range, air dissolved in the ink is separated and generated as air bubbles, thereby causing a problem of defective discharge. As described above, the above-described conventional method of modulating the ejection amount is 150% to 17%.
This is insufficient when it is desired to realize dot modulation in a practical range such as 0%.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to provide a configuration for appropriate density modulation. When performing density modulation by overprinting, it is possible to perform appropriate density modulation using a mask pattern, and particularly to obtain an optimal image by changing a mask pattern according to characteristics of a recording medium. A recording device is provided.

[0012]

According to the present invention, there is provided:
In an ink jet recording apparatus that performs recording by discharging ink from the ink jet recording head to a recording medium using an ink jet recording head, a scanning unit for causing the recording medium to scan with the ink jet recording head, and the scanning Means for generating ink ejection data for each of the plurality of scans using mask pattern data corresponding to each of the plurality of scans of the inkjet head performed on the same region of the recording medium by the means; When the ink ejection data generated by the ejection data generating means has different numbers of ejections with respect to the number of ejections for the same location, and the recording medium used for recording is of a predetermined type, the ink ejection data with a greater number of ejections The mask pattern that generates the data will have regularity , Characterized in that comprises a control unit for changing the mask pattern data used by the ejection data generation unit.

According to the above configuration, when a predetermined type of recording medium is used, the ejection data further includes
When different numbers of ejections are mixed for the number of ejections to the same location on the recording medium, the mask pattern for generating ejection data relating to the greater number of ejections is regular. The pattern of the ink dots formed by the ejection is regular. Even if the ink dot pattern becomes conspicuous in relation to the predetermined type of recording medium, the regularity does not cause deterioration in image quality.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

In one embodiment of the present invention, a thinning mask pattern for generating dot data to be used in each recording is used when an image is completed by multiple recordings.
It is characterized in that it can be changed depending on the recording medium to be used and the designated recording mode.

Also, there are three possible methods for performing overprinting a plurality of times and ejecting ink one time or more. The first method is, for example, a method of first performing 100% duty printing on the original image in the first scan, and additionally printing dots in accordance with the density in the second scan. At that time, the recording medium is transported between the first and second scans (hereinafter, simply referred to as paper feed).
And a method in which the paper is fed by, for example, １ ／ of the recording width. Further, it is also possible to combine a method of performing the first scan on the outward path and performing the second scan on the return path.

In the second method, similarly, 1 / n of the recording width is used.
(N is a natural number), and a printing method (hereinafter also referred to as fine printing) in which an image is completed by a plurality of printing scans using a thinning mask that is interpolative with each other. Is completed, and additional dots are formed according to the density without further paper feeding.

A third method is to use a pattern in which a dot pattern to be added to a thinning mask pattern in fine printing is added in advance, and when an image is completed by n scans,
This is a method of making the ink ejection amount twice or more.

Further, an optimum image is obtained by changing the type of the thinning mask depending on the type of the recording medium.

(First Embodiment) FIGS. 1 to 5 show an ink jet unit IJU, an ink jet head IJH, an ink tank IT, an ink jet cartridge IJC, an ink jet recording apparatus main body IJR to which the present invention is applied.
FIG. 3 is an explanatory diagram for explaining each of A and a carriage HC and a relationship between each of them. Hereinafter, each component configuration will be described with reference to the drawings.

(I) Main Unit FIG. 1 is an external view of an ink jet recording apparatus IJRA according to an embodiment of the present invention. In FIG. 1, a lead screw 5005 rotates via driving force transmission gears 5011 and 5009 in conjunction with forward and reverse rotations of a driving motor 5013, and a pin (not shown) provided on a carriage HC in a spiral groove 5004 thereof. Engage. Thereby, the carriage HC can reciprocate in the directions of the arrows a and b. Reference numeral 5002 denotes a paper pressing plate, which feeds a paper P as a recording medium over a platen 5000 in the carriage moving direction.
Press against Reference numerals 5007 and 5008 denote photocouplers, which constitute home position detecting means for confirming the presence of the lever 5006 provided on the carriage HC in this breath and switching the rotation direction of the motor 5013 and the like. Reference numeral 5016 denotes a member for supporting a cap member 5022 for capping the front surface of the print head. Reference numeral 5015 denotes suction means for performing suction by using a negative pressure in the cap, and performs suction recovery of the print head through the cap opening 5023. 5017, a cleaning blade;
Are members that allow the blade to move in the front-rear direction, and are supported by a main body indicating plate 5018.
It is needless to say that the cleaning blade is not limited to this embodiment, and a known cleaning blade can be applied to the present embodiment.
Reference numeral 5012 denotes a lever for starting suction for suction recovery. The lever 5012 moves with the movement of the cam 5020 engaging with the carriage, and the driving force from the drive motor is transmitted by a known transmission means such as clutch switching. Movement is controlled.

The capping, cleaning, and suction recovery are configured so that desired operations can be performed at the corresponding positions by the action of the lead screw 5005 when the carriage moves to the home position side area. Of course, any configuration can be applied to this example as long as a desired operation is performed at a known timing.

The ink jet cartridge IJ in this embodiment
C is a shape in which the ink storage ratio is increased, and has a shape in which the tip of the ink jet unit IJU projects slightly from the front of the ink tank IT. This ink jet cartridge IJC is of a type that can be attached to and detached from the carriage HC of the ink jet recording apparatus main body IJRA.

(Ii) Ink jet unit IJU The ink jet unit IJU is a unit of the type that performs recording using an electrothermal converter that generates thermal energy for causing ink to cause film boiling according to an electric signal. .

(Iii) Heater Board FIG. 2 is a schematic diagram of a heater board 100 which forms a part of the ink jet unit IJU.

A temperature control (sub) heater 8d for controlling the temperature of the head, a discharge array portion 8g provided with a plurality of discharge (main) heaters for discharging ink, and a drive element 8h are shown in FIG. Are formed on the same substrate in such a relationship. In addition, FIG. 3 shows the positional relationship of the outer peripheral wall cross section 8f of the top plate, which is divided into a region where the heater board is filled with ink and a region where the heater board is not filled. The discharge heater side of the outer peripheral wall section 8f of the top plate functions as a common liquid chamber. A liquid path is formed by a groove (not shown) formed corresponding to the ejection row portion 8g of the top plate.

(Iv) Control Configuration Next, a control configuration for executing recording control of each section of the above-described apparatus configuration will be described with reference to FIG.

In the figure showing a control circuit, 10 is an interface for inputting a recording signal, 11 is an MPU, 12
Is a program ROM for storing a control program executed by the MPU 11, and 13 is a dynamic RAM for storing various data (such as the print signal and print data supplied to the head) and mask data to be described later. The number, the number of replacements of the inkjet head, and the like can be stored. A gate array 14 controls supply of print data to the print head 18, and also controls data transfer between the interface 10, the MPU 11, and the RAM 13. Reference numeral 5013 denotes the recording head 18 as described above.
And 19 is a transport motor for transporting the recording paper. 15 is a head driver for driving the head, 16 and 17 are transport motors 19, respectively.
The motor driver drives the carrier motor 5013.

FIG. 4 is a circuit diagram showing the details of each part in FIG.

The gate array 14 includes a data latch 14
1, a segment (SEG) shift register 142, a multiplexer (MPX) 143, a common (COM) timing generation circuit 144, and a decoder 145. The recording head 18 has a diode matrix configuration, and a drive current flows through the ejection heaters (H1 to H64) where the common signal COM and the segment signal SEG match, thereby heating the ink and generating bubbles. ,
Discharge is performed by the pressure of this bubble.

The decoder 145 decodes the timing signal generated by the common timing generation circuit 144 and selects one of the common signals COM1 to COM8. The data latch 141 latches the recording data read from the RAM 13 in 8-bit units, and the multiplexer 143 stores the recording data in the segment shift register 1.
In accordance with 42, it is output as segment signals SEG1-8. The output from the multiplexer 143 can be variously changed according to the contents of the shift register 142, such as 1-bit unit, 2-bit unit, or all 8 bits, as described later.

The operation of the above-described control structure will be described. When a recording signal is transferred to the interface 10, the recording signal is converted by the gate array 14 and the MPU 11 into recording data for printing. And the motor driver 1
The printheads 6 and 17 are driven, and the printhead is driven according to the print data sent to the head driver 15 to perform printing.

FIG. 5 is an explanatory diagram for explaining the processing and flow of print data inside the printing apparatus described above.

The recording data sent from the host computer is stored in a reception buffer inside the recording device via the interface. The reception buffer has a capacity of several kilobytes to several tens kilobytes. After the command analysis is performed on the recording data stored in the receiving buffer, the data is sent to the text buffer. In the text buffer, recording data is held as an intermediate format for one line, and the recording position of each character,
Processing for adding the type, size, character (code), font address, and the like of the decoration is performed. The capacity of the text buffer differs for each model, and a serial printer has a capacity for several lines, and a page printer has a capacity for one page. Further, the print data stored in the text buffer is developed and stored in a print buffer in a binarized state, and a signal is sent to the print head as print data to perform printing. In this embodiment, the binary data stored in the print buffer is subjected to the following mask pattern data processing, and then a signal is sent to the print head.

In the ink jet recording apparatus of this embodiment described above, the density is not increased (the density is 1
X) Recording on plain paper and transparency film to increase density 1.5 times (hereinafter also referred to as TP film)
The recording in the fine mode will be described in detail below.

FIG. 6 is a diagram for explaining a recording method used in this embodiment. In the present embodiment, as shown in FIG.
A predetermined area is recorded by four scans. That is, the plurality of ink ejection ports of the recording head are divided into four, and each of the divided ejection port groups is used for recording corresponding to each of the predetermined areas.
Each time scanning is performed, the sheet is conveyed by the width of the ejection port group. For example, the first recording area located at the uppermost end of the recording medium P is
In the first print scan, printing is performed using the lowermost discharge port of the four divided discharge port groups of the print head 18, and the conveyance of the recording medium P corresponding to the width of the one discharge port group is performed. Is performed, the second printing apparatus prints the first print area using the second ejection port group from the bottom of the print head 18. At this time, the lowermost ejection port group is used for recording in a second recording area, which is another recording area. Hereinafter, in the third and fourth scans, similarly, printing of the first recording area is performed using different ejection port groups, and the second to fourth printing areas are recorded using different corresponding ejection port groups. A record is made.

In the present embodiment, in the printing method described above, a mask is used for each scan, and a desired density is obtained by four masks used in each of the four scans. For example, in the four scans for printing the first print area, four masks A1, B1, C1 and D1 are used as shown in FIG. Alternatively, it realizes 1.5 times the density.

FIG. 7 is a diagram for explaining the configuration of the above-mentioned mask in the memory space.

The mask data is set on a predetermined RAM, and this setting is made based on density information corresponding to a recording medium and the like, which is sent from the host device every time one page is printed. is there. The space for mask data on the RAM is 4 bytes in the column direction and 8 bytes in the raster direction.
It has a capacity of a total of 32 Kbytes for K columns, one quarter of which is a space for a mask pattern corresponding to one scan of each of the above recording areas. That is, each of the ejection port groups of the above-described recording head includes 32 ink ejection ports,
Therefore, 4 bytes (= 3
(2 bits) 1 column mask data is collected in a number equivalent to 56.8 characters that can be printed in one scan, and each is 1
The mask data A, B, C and D for the scanning are formed. Further, as will be described later, these four mask data are complementary to each other and have a 100% duty, that is, 1%, by superimposing the four mask data.
The mask data is generated as mask data that enables double printing four times, or the four mask data are adjusted appropriately and the complementary and overlapping dots are formed by superimposing the four mask data. It is generated as mask data that enables printing at 1.5 times the density with a portion.

In the mask data on the RAM, the read position can be set by a pointer. In the present embodiment, the memory data A to D are respectively "1" to "8".
Are set, whereby the mask data A1, B1, C1, D1,... Described above with reference to FIG. 6 can be read. For example, the mask data A1 indicates the mask data read for the data A by the pointer "1", and the data B1, C1, and D1 are similarly read by the respective pointers "1". That is, in this case, the mask data corresponding to 56.8 characters up to the end of the data of 256 columns partitioned by the pointer “8” starting from the data indicated by the pointer “1” is read. The mask data A2, B2, C2, and D2 are similarly divided into 56.8 characters in the respective areas from the data indicated by the pointer "2" to the end to the end of the data sectioned by the pointer "1". The corresponding mask data is read. Hereinafter, the mask data A3, B3, C
Similarly, for D3, A4, B4, C4, D4,..., The head of the mask data is read out as sequentially shifted mask data by 256 columns corresponding to the interval between the pointers.

Therefore, the same mask pattern is read out with the pointer at the same position in the eighth printing apparatus after the printing scan. By employing such a data reading configuration, the periodicity of the mask data reading does not appear in a relatively narrow recording area, and it is observed that a different mask is used for each recording area. As described above, by simply shifting the read pointer for the same mask data, it is possible to obtain substantially the same effect as using a different mask pattern for each recording area.

FIG. 8 is an explanatory diagram showing the configuration relating to the mask data of the present embodiment described above as a result of printing. In the printing method described with reference to FIG. 6, the density is increased by one using the mask data described above. This shows a case where recording is performed at 100% duty. In FIG. 8, each recording area of each scan is assumed to have a smaller number of dots than the actual number of dots for simplicity of description, and the pattern difference according to the shift of the pointer is omitted.

As shown in the figure, the first scanning
When printing a print area, dots are formed based on ejection data (dot data) generated using the mask data A1. FIG. 3 shows beading caused by the combination of unabsorbed ink between dots formed in this way and mainly adjacent dots. In the first printing area, printing is performed using the mask data B1, C1, and D1 in the second, third, and fourth printing scans, respectively, and finally these are formed by these four scans. It is possible to obtain a printing result of 100% duty in which the dots are arranged complementarily to each other (see the dot arrangement in the first printing area in the fourth printing apparatus in FIG. 8). .. For the other second, third,.
Recording of% duty is performed.

The dot formation shown in FIG. 8 schematically shows the mask data. When the ejection data (dot data) is so-called 100% solid printing, the dot formation as shown in FIG. However, in the case of other ejection data, it goes without saying that dot formation as shown in FIG. It is clear that the dots shown in the figure indicate mask data that makes the ejection data of the pixel valid. Further, the example shown in FIG. 8 is for explaining mask data with a density of 1 ×, and it is apparent that mask data for 1.5 times the density described later is not the same.

Next, a configuration for generating the mask data described with reference to FIG. 7 will be described below.

The mask pattern used in the present embodiment has a random pattern, as can be seen from FIG. 8, and FIG. 9 shows the generation of mask data related to a density one times that of the random pattern. FIG.

First, in step S1, a mask having the same size as the mask data size corresponding to one scan shown in FIG. 7 is set, and the same number of four parameters a, b, and
Fill with c and d. Then, in step S2, a pair of parameters is randomly selected from those parameters, and exchanged (substituted). This is performed a plurality of times to generate a mask in which each parameter is randomly arranged. The number of times of replacement is arbitrary as long as the number of times is such that the mask has randomness.
It should be performed 00 × 15 times. The mask data having the parameters of the random arrangement obtained in this way is stored in the ROM in advance.

Further, in step S3, a thinning mask corresponding to each scan is created. For example, the parameters a, b, c, and d are set to correspond to the mask data A, B, C, and D shown in FIG. 7, respectively, and the corresponding parameters (for example, the parameters corresponding to the parameter a when the mask A is created) A mask is created by setting a pitch “1” only at the position where “exists”.

In such mask data creation, since the positions of the parameters are originally arranged randomly,
The created mask also becomes a random mask pattern having a random arrangement. Further, since the mask data corresponding to each of the four scans is created from the same mask data, the mask data is always a random mask pattern that can be complemented 100%. The above-described parameter selection and parameter scanning are executed under the control of the CPU, and the created mask is stored in the RAM and used as described above.

FIG. 10 is a diagram for explaining the relationship between the CPU, ROM, and RAM involved in the mask data creation described above. In the present embodiment, as described above, random array data is stored in the ROM, and a random mask is created based on density information sent from the host computer every time one page is printed, and stored in the RAM. It is something to keep. The mask data stored in the RAM is read when the carriage is ramped up in each print scan, and is ANDed with print data (ejection data) temporarily stored in a print buffer, and based on the result, A record is made.

Accordingly, when creating a thinning mask for each scan as described above with reference to FIG. 9, it is possible to change the thinning mask in accordance with, for example, a printing mode or a recording medium to be used. For example, random mask patterns for 2-pass printing, 4-pass printing, and 8-pass printing can be created from the same random array data stored in the ROM.
The mode of this creation is determined by the number of types of parameters of the random array data (four types of a to d in FIG. 9). If this array data has 24 types (0 to 23) of parameters, By doing so, it is possible to correspond to a path of about several minutes. In other words, if two masks are created using the respective masks corresponding to 0 to 11 and 12 to 23, the masks correspond to 2-pass masks, and 0 to 7, 8 to 15, and 16 to 2
If three masks are created using the respective masks corresponding to 3, the mask corresponds to a three-pass mask. Hereinafter, it is possible to deal with masks for 4, 6, 8, 12, and 24 passes in the same manner.

As described above, instead of associating one parameter with one mask, by associating a plurality of parameters with one mask, there is printing having 100% or more overlapping dot formation. Double recording can be performed at a specific ratio, and the duty-up rate can be arbitrarily set by the number of parameters to be set. In the above example, if two masks are created using respective masks corresponding to 0 to 15 and 8 to 23, 1
It becomes 33%, and becomes 150% if two masks are formed by the respective masks corresponding to 0 to 17 and 6 to 23.

In the present embodiment, the type of the mask pattern is changed according to the type of the recording medium by using the method of changing the recording density by a factor of one or more. The mask pattern to be used is not limited to the random mask as described above, and a regular pattern may be used as one of the masks.

FIG. 11 is a diagram schematically showing a recording result when recording is performed at 1.5 times the density on a TP film using the above-described 150% random mask. The figure shows a case where black characters are recorded on a blue background at a density 1.5 times that of the blue background.

In this case, a large density difference occurs between a dot formed by the ink being ejected twice (two times) and another dot, and the dots of the overlapping ejection are randomly positioned. This may cause an unpleasant pattern on the recorded image.

This can be more specifically described as follows. For example, when printing is performed at a density of 1 time, a random mask pattern having a 100% duty is used, and dots of a random pattern are formed in the first printing scan as shown in FIG. At this time, unabsorbed ink of each dot is combined to cause beading, and as a result, these patterns are formed.

Similarly, adjacent dots also cause beading in the second scan. These all follow the pattern of the pseudo-random number, and the third and fourth scans produce a similar pattern to complete the image of the first recording area. Thereafter, since the second recording area, and further the third recording area, the fourth recording area,... Are recorded with different pseudo-random patterns in the respective areas, different beading patterns differ in each area in a microscopic manner. And a uniform image having no macroscopic regularity can be obtained.

However, even if a uniform image can be obtained when the density is 1 or 2 times, the observed pattern becomes uncomfortable when the density is 1.5 times as in the present embodiment. Sometimes. That is, the microscopically mixed portions of one and two ink ejections cause irregular optical random numbers and a density difference to be large between the one-time ejection and the two-time ejection. As a result, an unpleasant pattern is observed. FIG.
As can be seen from the right-hand image in which the circled portion of the image on the left is enlarged and displayed on the right side, since the light in the blue background portion is particularly transmitted, a portion with a random pattern having a high density and a portion having a low random This is because the portions of the pattern (the pattern is not shown in the figure) can be clearly distinguished, and the high-density portions appear to be very unpleasant because the light is scattered optically and appears dark.

Here, the TP film used in the ink jet recording system is formed by coating a surface of a plastic film typified by a PET film with a coating agent for absorbing and adsorbing ink. If the ink lands on the TP film at the timing, the ink has a tendency to beading due to the combination of the inks on the TP film due to the low absorption speed. On the other hand, when adjacent dots land with a time difference of several seconds, the dots are formed without being affected by the adjacent dots at all. Further, when the ink is ejected at a rate of one or more times, the portion swells more than the other portions and not only simply increases the density, but also causes optical scattering. This is not a serious problem when an image is viewed by surface reflection optically as in the case of recording on plain paper, but this optical scattering is a major problem when a transmitted image is viewed.

As described above, in the present embodiment,
For a recording medium having a density of 1 or more and using no transmitted light such as a plain paper mode, that is, a recording medium whose surface does not locally swell, a random mask pattern is used to form a TP film. As described above, a control that does not use a random mask pattern is performed for a device that uses transmission and performs an ink ejection more than one time. When this random mask is not used, printing is performed using a thinning pattern that interpolates regularly with each other. As a result, the pattern of the optical scattering and the density difference becomes a regular pattern, and the discomfort on the image is eliminated.

FIG. 13 schematically shows an image recorded on a TP film according to the embodiment. Even if additional dots (dots where the second ink is ejected) due to overlapping recording are remarkably observed. , They are arranged in a regular pattern so that they do not cause discomfort.

(Second Embodiment) In the second embodiment of the present invention, when printing at a density of 1 or more times, the first
In order for the effect of fine printing using the random mask described in the embodiment to appear in the printing result, an image of 1 × density is printed by four scans using the random mask pattern, and then the image is printed without paper feed. In the second scan, additional dots related to overlapping dots are formed. In this case, it is possible to print an image recorded at least at a density of 1 times without the occurrence of density unevenness due to the synchronization of the thinning mask and the image data, and the gradation of the additional dot image is lost due to the synchronization. It can be held down to the extent that it comes out.

Specifically, the superposition of the random mask used in the first embodiment increases the density by a factor of 100.
The print data is generated by setting the duty to be% and using a mask having regularity of 50% for the additional dots. When a recording medium capable of one-pass printing without beading is used, the first
100% recording may be performed in the second scan, and thereafter, 50% additional dots may be recorded without paper feeding.
At this time, when extracting additional dots, a mask to be used may be switched by judging whether to use a regular pattern or a random mask pattern.
Further, at this time, the paper may be fed by １ ／ of the recording width in the main scanning at the time of the second scanning for recording the additional dots, and fine recording may be performed by scanning a plurality of times for the additional dots. In addition, 1
00% printing may be performed, and 50% additional printing may be performed on the return path.

(Third Embodiment) In a third embodiment of the present invention, each of the thinning-out masks of four scans shown in the first embodiment, and additional dots of a portion exceeding one time of these masks are used. The recording data is generated by ORing with a mask for the above. Thus, unlike the second embodiment, it is possible to print additional dots in each print scan.

In this case, as in the second embodiment, for an image up to at least one portion, the image can be recorded without the occurrence of density unevenness due to the synchronization between the thinning mask and the image data, and additional dot data can be printed. Can be suppressed to such an extent that the gradation is lost due to tuning.

[0066]

As described above, according to the present invention,
In the case where a predetermined type of recording medium is used, and when the ejection data includes different numbers of ejections for the number of ejections at the same location on the recording medium, a mask for generating ejection data relating to a greater number of ejections Since the pattern is regular, the pattern of the ink dots formed by the ejection of the ink more times than the above becomes regular. Even if the ink dot pattern becomes conspicuous in relation to the predetermined type of recording medium, the regularity does not cause deterioration in image quality.

As a result, it has become possible to provide an ink jet recording apparatus capable of obtaining a high-quality image by appropriately increasing the density irrespective of the type of recording medium used.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of an ink jet recording apparatus suitable for carrying out the present invention.

FIG. 2 is a schematic plan view showing a configuration of a heater board constituting an ink jet recording head used in the apparatus.

FIG. 3 is a block diagram of a control mechanism for executing recording control and the like in the apparatus.

FIG. 4 is a block diagram showing a detailed configuration of a gate array and a recording head in the control mechanism.

FIG. 5 is a diagram showing a data flow from a host computer to a recording head of the apparatus.

FIG. 6 is a diagram for explaining a recording method according to the first embodiment of the present invention.

FIG. 7 is a diagram illustrating the development of random mask data on a memory according to the first embodiment.

FIG. 8 is a diagram schematically illustrating an example of a random mask according to the first embodiment based on a recording result.

FIG. 9 is a diagram for explaining a method of creating the random mask.

FIG. 10 is a diagram showing a relationship between a ROM for storing data of a random array and a RAM for storing mask data based on the data of the ROM, for creating the random mask.

FIG. 11 is a diagram schematically showing a printing result when printing is performed at a density exceeding one time using a random mask pattern.

12 is a diagram schematically showing a state where beading occurs in a first scan of the recording shown in FIG. 11;

FIG. 13 is a diagram schematically showing a printing result when printing is performed at a density exceeding one time according to the first embodiment.

[Explanation of symbols]

 11 MPU 12 ROM 13 RAM 14 Gate Array 18 Recording Head 19 Transport Motor 5013 Carrier Motor

Continuation of the front page (72) Inventor Osamu Iwasaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Daigoro Kanematsu 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (10)

[Claims] 1. An ink jet recording apparatus which uses an ink jet recording head to perform recording by discharging ink from the ink jet recording head to a recording medium, wherein scanning for causing the ink jet recording head to scan the recording medium. Means for generating ink ejection data for each of the plurality of scans using mask pattern data corresponding to each of the plurality of scans of the inkjet head performed on the same region of the recording medium by the scanning means. Generating means, and ink discharge data generated by the discharge data generating means,
When the number of ejections differing with respect to the number of ejections for the same location is mixed, and the recording medium used for printing is of a predetermined type, a mask pattern that generates ink ejection data with a greater number of ejections has regularity. And a control unit for changing mask pattern data used by the ejection data generating unit. 2. The ink ejection data of a larger number of ejections is ink ejection data relating to an ink dot to be additionally recorded, and the density of the entire recording image is increased by recording the additional ink dot. An ink jet recording apparatus characterized by the above-mentioned. 3. The ink jet recording apparatus according to claim 1, wherein the greater number of ejections is two. 4. The predetermined type of a recording medium is as follows:
2. A recording medium of a light transmission type.
4. The ink jet recording apparatus according to any one of items 1 to 3. 5. The light transmission type recording medium is a transparency film.
3. The ink jet recording apparatus according to claim 1. 6. The method according to claim 6, wherein the control unit uses random pattern data as mask pattern data for each of the plurality of scans, except when the number of times of ejection for the same location of the ink ejection data is different. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is used. 7. A mask pattern for generating ink ejection data of a greater number of ejections is obtained by converting mask pattern data corresponding to each of the plurality of scans into an ink ejection data of the greater number of ejections. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is generated by overlapping data. 8. The method according to claim 1, wherein the ink ejection data having the greater number of ejections is a rule for printing performed after printing based on ink ejection data obtained by mask pattern data corresponding to each of a plurality of scans each having a random pattern. 7. The ink jet recording apparatus according to claim 1, wherein the ink ejection data is obtained by using mask pattern data having characteristics. 9. The ink ejection data of the greater number of ejections is obtained by a logical OR of mask pattern data having regularity and mask pattern data having regularity and corresponding to each of the plurality of scans. 7. The ink jet recording apparatus according to claim 1, wherein the data is ejection data. 10. The ink-jet head according to claim 1, wherein bubbles are generated in the ink using thermal energy, and the ink is ejected based on the generation of the bubbles. Ink jet recording device.