JPH09272201A - Recording method and apparatus - Google Patents

Abstract

(57) [PROBLEMS] To provide a recording method and apparatus capable of effectively improving image quality by suppressing mutual interference between recording dots. When performing printing with a large number of dots based on print data, printing is performed only in a region other than a specific dot in a region where a plurality of these print dots are sequentially formed with a predetermined density or more. Method. Data input units 4 to 8 for obtaining the above print data, and a signal conversion unit for converting the print data into a print head drive signal
A printer including: 13, a drive unit 15, 37 that modulates and drives the print head by the conversion signal; and a print head 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording method and an apparatus therefor, for example, a printing method and a recording method for recording by causing a recording liquid composed of ink to fly in the form of liquid droplets to be deposited on a recording medium. It concerns printers.

[0002]

2. Description of the Related Art In recent years, as colorization of video cameras, computer graphics, and the like has progressed, the need for colorization of hard copies has rapidly increased. On the other hand, a color hard copy system such as a sublimation thermal transfer system, a melt thermal transfer system, an ink jet system, an electrophotographic system, and a heat-developed silver salt system has been proposed. Among these recording methods, methods for easily outputting high-quality images with a simple device can be roughly classified into a dye diffusion thermal transfer method and an inkjet method.

Among these recording systems, according to the dye diffusion thermal transfer system, an ink ribbon or sheet in which an ink layer in which a high-concentration transfer dye is dispersed is applied in a suitable binder resin, and the transferred dye. A transfer material such as photographic paper coated with a dyeing resin is attached under a certain pressure, heat is applied from the thermal recording head located on the ink sheet according to the image information, and it is received from the ink sheet. The transfer dye is thermally transferred depending on the amount of heat applied to the layer.

The above operation is performed by subtracting the three primary colors of subtraction,
The so-called thermal transfer method, which is characterized by obtaining a full-color image with continuous gradation by repeating each of the image signals decomposed into yellow, magenta, and cyan, is compact, easy to maintain, and instant. It is attracting attention as an excellent technology for obtaining high-quality images comparable to silver salt color photographs.

FIG. 15 is a schematic front view of the main part of such a thermal transfer type printer.

A thermal recording head (hereinafter referred to as a thermal head) 100 and a platen roller 101 face each other, and an ink sheet 102 having an ink layer 102a provided on a base film 102b and a paper 103b are dyed between them. The recording paper (recording medium) 103 provided with the resin coating layer 103a is sandwiched, and these are pressed against the thermal head 100 by the rotating platen roller 101 and run.

The ink (transfer dye) in the ink layer 102a selectively heated by the thermal head 100
Are transferred in a dot shape onto the dyeing resin layer 103a of the recording paper 103, and thermal transfer recording is performed. For such thermal transfer recording, a serial method in which a thermal head is scanned in a direction orthogonal to the running direction of the recording paper 103, or a line method in which one thermal head is fixed and arranged orthogonally to the running direction of the recording paper is used. And are adopted.

In addition to the thermal transfer method, a so-called ink jet recording method is known, but this recording method enables high-speed recording and can record on so-called plain paper without requiring a special fixing process. In recent years, it has become an effective recording method as a technique for hard copying images such as computer graphics.

The above-mentioned ink jet system is the Japanese Patent Publication Sho 6
As disclosed in Japanese Patent Publication No. 1-59911 and Japanese Patent Publication No. 5-217, etc., an electrostatic suction method, an electromechanical conversion method (piezo method), a thermal method (bubble jet method), or the like is used according to image information. A small droplet of the recording liquid is ejected from a nozzle provided on the recording head and adhered to a recording member to perform recording.

Therefore, since the waste is hardly generated and the running cost is low, the spread of the waste is expanding.

A so-called on-demand type ink jet (hereinafter, simply referred to as "ink jet") type printer device ejects ink droplets from a nozzle in response to a recording signal to record on a recording medium such as paper or film. Printers, which can be miniaturized and reduced in cost, are rapidly becoming popular in recent years.

In such an ink jet printer, in order to eject ink droplets, for example, a method using a piezo element or a method using a heating element is generally used.
The method using a piezo element is a method in which pressure is applied to ink by deformation of the piezo element and the ink is ejected from a nozzle.

FIG. 16 shows a conventional ink jet printer (for example, on-demand type).

First, the structure of the print head illustrated in FIG. 16A is a cylindrical tubular casing 11 made of glass or the like.
1 and a cylindrical electrostrictive element (piezo element) 112 provided on the outer surface of the casing 111. Further, the ink chamber 11 inside the casing 111 is provided at both ends of the casing 111.
Ink supply port 114 for filling 3 with ink 110,
Nozzle 11 for ejecting ink as ink droplet 115
6 and the orifice portion 117 are provided.

Then, a voltage generator is added to the electrostrictive element 112.
The electrostrictive element 112 is deformed by applying a predetermined voltage from 118, and this deformation causes the casing to be deformed.
The volume of the ink chamber 113 in the 111 changes. Due to this volume change, the internal pressure of the ink chamber 113 is increased, whereby the ink droplet 115 is ejected from the nozzle 116.

Therefore, by driving the voltage generator 118 with arbitrary print information, the ink droplets 115 can be ejected from the nozzles 116 based on the print information. And this ejected ink droplet
115 is attached to a recording paper (not shown) which is a recording medium,
Printing is performed.

Further, FIG. 16B shows an example of a print head using a flat electrostrictive element. In this print head, one surface of a casing 121 made of an arbitrary material is formed on a vibrating plate 122, and an electrostrictive element 123 is bonded to an outer surface of the vibrating plate 122 to form a so-called bimorph plate. Further, at both ends of the casing 121, there are an ink supply port 125 for filling the ink chamber 124 in the casing 121 with the ink 120, a nozzle 127 for ejecting the ink as ink droplets 126, and an orifice portion 128. It is provided.

The electrostrictive element 123 is connected to a voltage generator.
This electrostrictive element 123 is deformed by applying a predetermined voltage from 129, and this deformation causes the casing
The volume of the ink chamber 124 in 121 changes. Due to this volume change, the internal pressure of the ink chamber 124 is increased, whereby the ink droplet 126 is ejected from the nozzle 127.

Therefore, by driving the voltage generator 129 with arbitrary print information, the ink droplets 126 can be ejected from the nozzles 127 based on the print information. And this ejected ink droplet
126 is attached to a recording paper (not shown) which is a recording medium,
Printing is performed.

Further, FIG. 16C shows a so-called stem (2
An example of a chamber type printhead is shown. In this print head, one surface of a casing 131 made of an arbitrary material is formed on a vibration plate 132, and an electrostrictive element 133 is bonded to the outer surface of the vibration plate 132 to form a so-called bimorph plate. A pressure chamber 134 is formed in the casing 131, and an ink supply path 135 is provided in communication with the pressure chamber 134.

Further, an ink supply port 136 for filling the ink 130 into the ink supply path 135 is provided, and the ink supply path 135 is located at a position facing a communicating portion with the pressure chamber 134.
Nozzle 13 for ejecting ink as ink droplet 137
8 and an orifice portion 139 are provided.

A voltage generator is added to the electrostrictive element 133.
By applying a predetermined voltage from 140, this electrostrictive element 133 is deformed, and this deformation causes the casing 13
The volume of the pressure chamber 134 in 1 changes. Due to this volume change, the internal pressure of the pressure chamber 134 is increased, and the increase of this internal pressure is transmitted to the ink supply path 135, whereby the ink droplet 137 is ejected from the nozzle 138.

Therefore, by driving the voltage generator 140 with arbitrary print information, the ink droplet 137 can be ejected from the nozzle 138 based on this print information. And this ejected ink droplet
137 is attached to the recording paper (not shown) that becomes the recording medium,
Printing is performed.

On the other hand, FIG. 17 shows another example of the print head used in the above-mentioned ink jet printer (for example, on-demand type). For example, a heating element is used to eject ink.

According to the structure of this print head, the heating element 152 is provided inside the nozzle 151.
By supplying electric power to 152, the ink 150 in the nozzle 151 is instantaneously vaporized, and the ink droplet 157 is ejected from the tip 154 by the pressure of the bubble generated by this vaporization.

That is, in FIG. 17A, the heating element 152
When power is supplied to the ink 150 that contacts the heating element 152
Is heated and boiled, and a plurality of small bubbles 156 are generated. The plurality of bubbles 156 are collected into one large bubble 157 as shown in FIG. 17 (B), and the pressure of the bubble 157 causes the bubbles in FIG.
As shown in (C), the ink 150 in the nozzle 151 has the tip portion 154.
Extruded from.

Then, in the state of FIG.
When the power supply to the
The pressure in the nozzle 151 is reduced. This allows the tip 15
The ink pushed out from 4 is the ink 150 in the nozzle 151.
17D, the separated ink is ejected as an ink droplet 157 as shown in FIG.

Therefore, by driving the heating element 152 with arbitrary print information, the ink droplet 157 can be ejected from the nozzle 151 based on the print information. Then, the ink droplets 157 are attached to a recording paper (not shown) serving as a recording medium, and printing is performed.

By the way, when performing desired recording (formation of an image) on the recording paper using each of the above-mentioned print heads, for example, serial type printing is performed on the recording paper 180 as schematically shown in FIG. While scanning the head 16 in the main scanning direction, ink is ejected according to the image information and pixel
Attach as dots 181.

In this case, when the image quality is improved by the gradation (halftone) representation of the recording dots (pixels), print information may be formed with 8 bits = 256 gradations. On the other hand, when the number of halftones printed by the printer device is small (for example, 6 bits = 64 gradations), gradation expanding means such as a so-called multi-gradation dither method (multi-gradation error diffusion method as an example) is used.

That is, for example, in the multi-gradation error diffusion method, FIG.
As shown in, the level of any pixel A forming the image is changed from the original desired level X (256 gradations) to the actually printed level X '(normally 4, 6, 8, 1).
6, 32, 64 gradations, here 64 gradations as an example). In this case, the level to be replaced X '
Is used as a level, or a method of replacing the absolute value of the difference between level X ′ and a plurality of possible levels X ′ as a probability. In the latter method, level X'may be replaced by all possible levels.

Furthermore, the error component ε between level X and level X '
Is distributed to the pixels around the pixel A and added. In addition,
As shown in FIG. 19, the method of this distribution is such that each pixel A
(7/16) ε at the pixel next to, (3/16) ε at the pixel immediately before the next scan line, (5/16) ε at the pixel immediately below, and one after the next scan line. There is a method of distributing to pixels of (1/16) ε such as (1/16) ε, and a method of adding to only one arbitrary pixel with the probability of each distribution rate.

The error ε has a sign of ±. Further, the error of the surrounding pixels to which the error is distributed is calculated by adding the distributed error. Further, when the value obtained by adding the distributed errors exceeds the maximum print level or the minimum print level of the printable range, the amount exceeding the maximum print level or the minimum print level is ignored or rounded or exceeded. The process of redistributing the minutes to the surrounding pixels by the same calculation as the above-described error amount ε with the above-described ratio or probability is performed.

By thus distributing the error component ε of the pixel A to the surrounding pixels, the printing error is diffused, and this is performed over the entire input image, and the image data to be printed is created. The gradation of the image obtained when the print information is printed can be substantially expanded (for example, 64 gradations can be expanded to 256 gradations). In addition, the numerical values such as the distribution ratio above are examples,
It can be variously changed according to the difference of the converted gradation, the range (number) of pixels to which the error is distributed, and the like.

Therefore, for example, by using the above-mentioned dither method or the like in the host computer, from the print information of 8 bits = 256 gradations formed in the host computer, for example, 64 gradations that can be printed by the above-mentioned printer device. Print information is formed. In this case, for example, the print information of 64 gradations is represented by 6 bits, for example.

In FIG. 20, the input data (print information) indicated by the broken line is in the x direction by the above-described multi-gradation error diffusion method.
That is, it shows a state in which each dot is converted into print data having a corresponding gradation in the main scanning direction of the print head.

In this case, in the image to be printed, the total amount of the ink solution ejected from the print head is determined by the characteristics of the ink solution, the characteristics of the recording paper and the printing speed, but the ink on the recording paper is bleeding. However, there is a minimum print density at which the inks adjacent to each other are mixed, the color reproduction characteristics are deteriorated, the image quality is deteriorated, and the resolution is deteriorated.

Therefore, when the image to be printed has a continuous spread of the minimum density or more, the ink ejected to form one pixel is fixed on the recording paper, especially in the multi-gradation error diffusion method. Immediately after that, the next ink will be ejected to the adjacent position (or the same position), the total amount of ink will increase and the ink will bleed on the recording paper, or the ink will mix slowly due to slow drying. As a result, the color reproduction characteristics may deteriorate and the image quality may deteriorate, or the resolution may deteriorate. In order to avoid this, expensive exclusive recording paper is used, and the printing speed is also limited.

This is especially true when no dedicated recording paper is used (that is, when general-purpose recording paper such as low-quality high-quality paper or recycled paper is used), or when the environmental temperature during printing or printing is low. This often occurs when a head scan is performed, but it may also occur when a dedicated recording paper is used. Further, in a two-liquid mixing type printer (so-called carrier jet method) which will be described later, when the excess ejection ink solution is ejected onto the recording paper, this has a great adverse effect on the image quality, and a halftone (gradation) is obtained. The problem of becoming difficult is added.

[0040]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, suppress mutual interference between recording dots, and effectively improve the image quality, and a recording apparatus therefor. To provide.

[0041]

That is, according to the present invention, when recording is performed with a large number of dots based on recording data,
The present invention relates to a recording method in which only recording of specific dots is performed in an area where a plurality of these recording dots are sequentially formed at a predetermined density or higher.

According to the present invention, when printing is performed with a large number of dots, data input for obtaining print data capable of only printing other than a specific dot in an area where a plurality of these print dots are successively formed at a predetermined density or higher. Department,
The present invention also provides a recording device including a signal conversion unit that converts this recording data into a recording head drive signal, a drive unit that modulates and drives the recording head with this conversion signal, and a recording head.

Here, the above-mentioned "predetermined density" means that the recording material such as ink droplets is adhered to the recording material in a dot shape by a recording method such as an ink jet method, and the recording is carried out. It means the minimum concentration at which bleeding of the recording material adhered on the body and mixing of adjacent recording materials begin to occur.

According to the recording method and apparatus of the present invention,
In a region where a plurality of recording dots are formed at a density equal to or higher than the predetermined density, only recording other than specific dots is performed (conversely, specific dots are not recorded).
When one pixel is formed, the recording material adheres to the recording material such as recording paper, and immediately after this, recording is not performed at a specific dot position, so that the recording material on the recording material is fixed, Next, even if another recording material is attached to the adjacent position (or the same position) to form the next pixel, these recording materials do not interfere with each other.

That is, since one recording material sets specific dots and adheres and then solidifies, the other recording material adheres. Therefore, for example, when the pixel density is increased, the ink on the recording paper is bleeded. It is possible to suppress the mixing of the inks with each other to a minimum, the color reproduction characteristics are improved, a high image quality is obtained, and the resolution is improved.

As the recording medium, for example, when no dedicated recording paper is used (that is, when general-purpose recording paper such as high-quality paper or recycled paper which is low in cost is used), or the environmental temperature at the time of printing or printing is low. In this case, the above-mentioned remarkable effects can be obtained even when high-speed head scan is performed.
Therefore, it is possible to use inexpensive recording paper, which is advantageous in terms of cost as well as in terms of use and operation.

Furthermore, in a two-liquid mixing type printer (so-called carrier jet method) described later, when the halftone is improved by a dither method such as the above-described multi-gradation error diffusion method, the surplus ejected ink solution is left on the recording paper. It is possible to obtain the desired halftone (gradation) by suppressing the discharge to the target area, minimizing the adverse effect on the image quality.

[0048]

BEST MODE FOR CARRYING OUT THE INVENTION In the recording method and the apparatus thereof according to the present invention, specifically, when a recorded image composed of a large number of recording dots has a continuous spread at a predetermined density or more, specific dots existing at regular intervals. Can not be recorded.

In addition, a large number of dots are recorded by the multi-gradation dither method for obtaining a recorded image having gradation, and the recording data of specific dots which are not recorded are distributed to the surrounding dots. Is desirable.

When ink droplets are deposited on the recording medium by the ink jet method to perform recording, bleeding of the ink deposited on the recording medium and mixing of adjacent inks start to occur. In a region where a large number of recording dots are formed at the minimum density or higher, it is desirable that ink droplets are not ejected for specific dots that are present at regular intervals.

As the ink jet system, it is preferable to employ a so-called carrier jet system in which a fixed amount of ink and an ink diluting liquid are mixed and recording droplets are deposited in a dot shape on a recording medium to perform recording.

[0052]

Embodiments of the present invention will be described below.

First, referring to FIGS. 1 and 2, an outline of the recording method by the ink jet printer according to the present invention will be described.

In this embodiment, in a two-liquid mixing type ink jet printer (so-called carrier jet type printer) described later, a multi-tone dither method represented by a multi-tone error diffusion method is used as a halftone expressing means. This is performed in the same manner as described with reference to FIG. 19, so description will be omitted here.

However, as described above, the image to be printed is
In the past, it was impossible to avoid ink bleeding and mixing when the ink spreads continuously over a certain density. Here, the “constant density” means that the total amount of the ink solution ejected from each print head is determined by the characteristics of the ink solution, the characteristics of the recording paper, and the print speed, but the ink on the recording paper may bleed. , The adjacent printing inks are mixed with each other, the color reproduction characteristics are deteriorated, the image quality is deteriorated, and the resolution is deteriorated.

Therefore, according to the present embodiment, the method of the multi-gradation dither method in the portion having the spread of a certain density or more is applied, and as shown in FIG. The data is interrupted and the ejection of the ink solution from the head is stopped.

That is, the method of the multi-gradation error diffusion method is applied to the two-liquid mixing type ink jet printer, and the print head is constructed so as to stop the ink ejection in the low print density portion.
For example, every other dot is converted into print data for stopping the ejection of the ink solution from the print head, and the input data and the print data for the print head are distributed to the peripheral pixels according to the rule of the multi-gradation error diffusion method.

That is, if the pixel A is the above-mentioned specific dot as shown in FIG. 2A, the error amount is distributed to the surrounding pixels (dots) by a usual method, and as shown in FIG. 2B. , The image level itself of the pixel A is further distributed to the surrounding pixels to make it the zero level. Therefore, the ink is not ejected for the pixel A, and the printing data as shown in FIG. 1 can be obtained by performing this at regular intervals. This print data is used for signal conversion → head modulation drive described later.
It should be noted that, as in the case of the pixel A, the influence of the pixel omission due to the non-discharge of ink does not substantially occur.

As described above, according to the method of this embodiment, the total amount of ink ejected from the print heads is controlled by each print head to print image data for every one dot (or every other dot). It is converted to a value that means "no ink is ejected" (for example, "00"), and since no ink is actually ejected, the total amount of ink in a certain area including its surroundings is determined by the characteristics of the recording paper used. Ink amount corresponding to the determined print data whose image quality starts to deteriorate (the above-mentioned constant density)
Can be kept below.

As a result, ink bleeding on the recording paper,
Since the mutual influence of the inks adjacent to each other due to the delay in drying is reduced, the color reproducibility becomes good even when printing a plurality of colors, and the image quality and the resolution can be improved. Also, various inexpensive recording papers can be used, and the printing speed can be increased.
And so on.

FIG. 3 to FIG. 8 show the above-mentioned recording method by a two-liquid mixing type ink jet printer (carrier jet method).
FIG. 2 shows a sequence and its circuit configuration when applied to, and a usable print head.

First, the circuit operation for carrying out the recording (printing) method will be described with reference to FIG. 3. The following operation follows a program stored in a ROM (Read Only Memory) 6 and a CPU (Central Processing Unit). ) 5 sequentially.

Data input interface (hereinafter, I
/ F. 4), input data to be printed is received and stored in a RAM (Random Access Memory) 7. The data input I / F controls so that the input data does not overflow on the RAM 7, and when the input data on the RAM is full, the input data is stopped by the input data control signal.

At this time, if the RAM size can store the entire image to be printed, it may move to the next process after storing all the input image data, or the entire image to be printed is stored. If not possible, the number of lines more than the number of lines used in one scan of the actual print head may be stored, and the input data may be stopped by the input data control signal.

When the input data to be printed stored in the RAM reaches the number of lines used in one scan of the actual print head, the temperature of the thermistor or the like attached to the ink jet print head is changed. Sensor 40
Is measured as temperature measurement data via the sensor I / F 41. The difference between the measured temperature calculated here and the standard operating temperature of this printhead (the temperature assumed at the time of design) is calculated, and the correction curve for the input data (correction amount for the value of the input data) corresponding to this temperature difference is obtained. Curve) is obtained.

The relationship between this temperature difference and the corresponding correction curve for the input data is as follows:
It was decided at the time of development of recording paper. The correction curve may be the same or different for all values of the input data. This is mainly obtained by actual measurement during development.

When the correction curve is determined, the input data is converted based on the correction curve to obtain corrected print data. The correction of the input data by the temperature measurement is not always necessary.

After being converted to the corrected print data, the image data to be actually printed is replaced by the multi-gradation error diffusion method described later. The replaced image data is stored in another place in the same RAM 7. It should be noted that the plurality of gradation numbers in the multi-gradation error diffusion process are usually 4, 6,
There are about 8, 16, 32, and 64 stages.

The relationship between the number of gradations and the voltage level applied to the electrostrictive oscillator 52 is the cause of instability of the displacement of the electrostrictive oscillator (hysteresis characteristic, change in applied waveform due to having capacitance). Instability of modulation operation of the entire head (error in modulation characteristics due to variations in head assembly, variations in modulation characteristics due to physical properties such as ink viscosity and vibration plate characteristics), ink on recording paper against changes in applied voltage It is determined based on the relationship of the change in density within the dot. The electrostrictive oscillator 52 is a device that causes a phenomenon of being deformed or distorted when an electric field is applied to the dielectric (referred to as a piezo element: the same applies hereinafter).

When the number of print data replaced on the RAM 7 as described above is stored for driving the ink jet print head (in the case of a head drive type printer having several tens of ink jet head nozzles). ,
When the number of prints for one scan of the head is stored), the image data to be printed is sent to the D / A converter 13 as a print data signal, and at the same time, a motor drive control signal is sent to the motor controller 19. , Operate the head feed motor.
A motor drive unit 20 is provided between the motor control unit 19 and each motor 21, and drives a signal to a voltage and current value capable of driving the motor.

When the head feed motor 21 is activated and the nozzles of the print head 16 reach the position on the recording paper to be printed, the timing control section 18 detects the timing by the output from the head position detection sensor 17, and D / A converter
A D / A conversion trigger signal is output to 13. Further, it also outputs a motor drive trigger signal to the motor control unit 19.

In the D / A converter 13, the image data to be printed included in the print data signal is converted to a predetermined voltage level. This was explained in the above process.

-1 The modulation oscillator drive signal corresponding to the image data to be printed, which has been converted to a certain voltage level, is necessary for the modulation oscillator drive section 15 to displace the modulation electrostrictive oscillator. The power is amplified to an appropriate power and input to the print head modulator 37 as a modulation oscillator application signal. In the print head modulator 37, a fixed amount of ink and a mixing operation of the ink and the solvent are performed.

-2: After applying a modulation oscillator application signal to the print head modulation unit 37 for a predetermined fixed time, the modulation oscillator application signal is invalidated, and the ink and solvent are applied by the print head modulation unit 37. The mixing operation with (diluting liquid) is completed.

-3 After the completion of this mixing operation, the timing control section 18 outputs an ejection timing signal to the ejection oscillator drive section 38. This ejection timing signal is amplified by the ejection oscillator drive unit 38 to the electric power required to displace the electrostrictive oscillator for ejection, and is input to the print head ejection unit 36 as an ejection oscillator application signal. In the print head ejection unit 36, the print head modulation unit 37 supplies a predetermined amount of ink modulated according to image information, mixes it with a solvent, and ejects it as an ink solution to form an ink dot of a desired concentration. Form on recording paper.

-4 In this way, when one ink dot is formed on the recording paper, the next ink dot is formed. That is, the image data to be printed next, which has been replaced on the RAM, shown in the above, is sent to the D / A converter 13 as a print data signal. For -5 or less, the above-mentioned operations -4 are repeated.

The paper feed motor 21 feeds the recording paper as needed in synchronization with the drive of the print head.

By repeating the above operation, paper feeding, head feeding, voltage application to the head, and ejection are performed.

In the above operations (1) to (2), the input data is converted into the data shown in FIGS.
Since data as shown in (B) is obtained and supplied to the head as a modulation signal, when one pixel is formed,
Ink adheres to the recording paper, and immediately after this, recording is not performed,
Therefore, even if the ink on the recording paper is fixed and another ink is attached to the next adjacent position (or the same position) to form the next pixel, these inks do not interfere with each other. There is no.

In the above operation, the data conversion process based on the multi-gradation error diffusion method is performed in the printer. However, these data conversion processes are performed on the computer and the processing result is transferred to the printer. May be.

Therefore, the ink on the recording paper may bleed,
Mixing of inks can be suppressed to a minimum, color reproduction characteristics can be improved and high image quality can be obtained even when printing with a plurality of colors, and resolution can be improved. For this reason, in a two-liquid mixing type printer (so-called carrier jet method), an excessive amount of ejected ink solution is prevented from being ejected onto the recording paper, the adverse effect on the image quality is minimized, and the target halftone (gradation ) Can be obtained satisfactorily.

As the recording paper, for example, when no dedicated recording paper is used (that is, when general-purpose recording paper such as low-quality high-quality paper or recycled paper is used), or when the environmental temperature at the time of printing or printing is low Even in the case of performing high-speed head scanning, the above-described remarkable effects can be obtained, so that recording paper with low cost can be used, which is advantageous in terms of cost, and is also advantageous in terms of use and operation.

FIG. 4 shows the circuit configuration of the ink jet printer shown in FIG. 3 in more detail. In FIG. 4, for example, image information (print information: information including a dither method described later) formed by the host computer 150 (including a dither processing unit) and print command information are, for example, Centronics, Bicentronics ( IEEE Std 1284), SCSI (above, parallel)
Alternatively, the data is supplied to the printer device using a data interface (I / F) defined by RS232C, RS422 (above, serial), or the like.

Here, for example, the above-mentioned IEEE Std 1284
Interface specified by (Bicentronics)
In, transmission lines numbered 1 to 36 are provided. And
The first transmission path among them is strobe (enable), and the second to ninth transmission paths transmit 8-bit information.

The 8-bit command information formed by the main body 151 of the host computer 150 is directly supplied to the interface (I / F) circuit 152 and transmitted through the above-mentioned transmission lines 2-9.

On the other hand, the print information is formed in the main body 151 of the host computer 150, for example, in 6 bits according to the performance of the print head which will be described later. Therefore, this 6-bit print information is provided and transmitted in the above-mentioned transmission lines on, for example, the 4th to 9th transmission lines on the MSB side, and the 6-bit print information is transmitted to the 2nd transmission line, for example, the LSB. The error detection data for the print information of is provided.

That is, for example, the 6-bit print information from the main body 151 is added to the error detection data addition circuit 153.
Is supplied to. Then, in the additional circuit 153, the above 6
For bit print information, for example, even parity,
1-bit error detection data such as odd parity or "0" when all 6 bits are "1" and / or "1" when all 6 bits are "0" is formed.

The error detection data is arbitrarily selected according to the environment in which the printer is used. That is, for example, in an environment in which a high-voltage power supply path or the like exists near the transmission path and an error is likely to occur such that all 6 bits are “1” or “0”, all 6 bits are “1”. Error detection data that is "0" and / or "1" when all 6 bits are "0".

Further, when there are a plurality of factors in the occurrence of an error such as the sources of high frequencies being close to each other, even parity or odd parity is selected as the error detection data. Further, these error detection data may be configured so that selection can be arbitrarily switched. Then, the selected error detection data can be transmitted to the receiving side, which will be described later, by the corresponding command information so that the processing is performed.

Further, the 1-bit error detection data is provided with print information in 6 bits on the MSB side.
It is added to the LSB of the bit. Then, the 8-bit print information to which the error detection data is added is supplied to the interface circuit 152 and transmitted through the above-mentioned transmission lines 2-9. The third transmission path is, for example, "empty" in this example, and designated data is provided and transmitted.

Then, the control signal from the main body 151 is supplied to the interface circuit 152, and the command information and print information are arbitrarily selected and transmitted.

In the above command information, for example, (designating command of print mode) + (designating parameter such as [full-color high-quality / full-color plain paper / black-and-white image / character]), (designating command of print information transfer method)
+ (Specified parameter such as [with / without compression]),
A specified command such as (specified command of interleave operation) + (specified parameter such as [execute / not execute]) is transmitted.

In the above command information, for example, (main scanning direction reference unit setting command) + (reference minimum unit distance length setting parameter), (sub scanning direction reference unit setting command) + (reference The minimum unit distance length setting parameter), (print speed setting command) + (setting parameter), (resolution setting command) + (setting parameter), and other setting commands are transmitted.

In addition, in the above command information, a part of the command information transmitted from the printer body described later to the circuit block including the print head is also transmitted. The command information is transmitted in a random order, for example, at the start of printing or the like.

Further, in the above command information, for example, (setting command of print position movement in the main scanning direction) +
(Print start position setting parameter), (Print position movement setting command in the sub-scanning direction) + (Print start position setting parameter), (Print data number setting command to be transferred) + (Data transfer number setting parameter) , (Data transfer end command), (print operation end command), etc. are transmitted. These command information are transmitted at any time as parameters are changed.

When the above (command for setting number of print data to be transferred) + (parameter for setting number of data transfer) is formed in the main body 151, a control signal from the main body 151 is supplied to the interface circuit 152. The selection is switched from the command information to the print information. With this, thereafter, the additional circuit 153 described above is used.
The print information added with the error detection data is transmitted.

Further, the print information is transmitted by the number set in the above (parameter for setting the number of data transfers). When the set number of transmissions are performed, the control signal from the main body 151 is transmitted again to the interface circuit 152.
And the selection of the print information is changed to the command information. Then, the above (data transfer end command) is transmitted, and thereafter, the command information is transmitted.

In this way, the command information and print information formed in the main body 151 of the host computer 150 are transferred from the interface circuit 152 to, for example, the IE.
It is transmitted to the interface (Bicentronics) specified by EEStd 1284.

The transmitted command information and print information are received by the data input / output interface (I / F) circuit 4 of the printer device. The command information received by the interface circuit 4 is directly supplied to the CPU system bus 8 inside the printer. The system bus 8 includes a CPU (central processing unit) 5, a ROM (Read Only Memory) 6, and an R.
In addition to an AM (Random Access Memory) 7, a circuit mechanism for printing described later is connected.

Then, the above command information is, for example, CP.
It is supplied to U5 and, for example, the above-mentioned (setting command for the number of print data to be transferred) + (setting parameter for the number of data transfers) is determined. Further, when the command information is discriminated, the control signal is supplied to the interface circuit 4, and the switching is performed so that the received data is supplied to the error detection circuit 3, for example.

Therefore, the error detection circuit 3 detects an error in the transmitted print information by using the error detection data added by the addition circuit 153 of the host computer 150, for example. When no error is detected, 6 bits on the MSB side of the transmitted print information are directly supplied to the system bus 8.

On the other hand, if an error is detected in the print information transmitted by the error detection circuit 3, the print information in which the error is detected is corrected. That is, in this correction process, for example, when an error is detected, the corresponding print information is replaced with blank data. Alternatively, processing such as replacing the corresponding print information with the immediately preceding data is performed.

Further, this error correction processing is performed by the above CP.
You may make it jointly perform with U5, RAM7, etc.
In that case, the corresponding print information is replaced with the data of the adjacent scan lines or the average value data thereof. Furthermore, it is possible to perform processing such as requesting the host computer 150 side to re-transmit print information in which an error has been detected.

Further, command information supplied to a head carriage (circuit block including a print head) 81, which will be described later, formed by the CPU 5, for example, is supplied to the system bus 8. Further, the command information supplied to the head carriage 81 is supplied from the system bus 8 to the command information / print information combining circuit 82.

On the other hand, the print information (6 bits) is sent from the system bus 8 to the above-mentioned error detection data addition circuit 153.
Similar to or any error detection data addition circuit 83
Is supplied to. Then, the print information (8 bits) to which the error detection data is added by the addition circuit 83 is supplied to the command information / print information combining circuit 82.

Then, the data from the synthesis circuit 82 is
Along with enabling, the command information on the head carriage 81 and the print information separating circuit 84 are supplied. here,
Since the synthesizing circuit 82 on the printer main body side and the separating circuit 84 on the head carriage 81 are usually provided in the same casing, the specification of data transmission between them is arbitrary.

However, for example, in the command information, it is desired to follow the system of the command information from the host computer 150 and the head carriage 81.
For the reason that the transmission line cannot be made heavy in order to smoothly perform the reciprocating motion of the, the transmission line between the combining circuit 82 and the separation circuit 84 also has, for example, 8 bits in the transmission line for data transmission. The width is used.

Therefore, even in the above-mentioned additional circuit 83, for example, 6
For the original print information of the bits, for example, even parity, odd parity, or “0” when all 6 bits are “1”, and / or “1” when all 6 bits are “0”, etc. 1-bit error detection data is formed. The 1-bit error detection data is 6
The bit print information is added to the 8-bit LSB provided on the MSB side.

In this way, the command information and the print information formed in 8 bits, for example, are supplied to the synthesizing circuit 82. Further, for example, a control signal formed by the CPU 5 is supplied to the synthesizing circuit 82, and the above command information and print information are arbitrarily selected and transmitted.

The transmitted command information and print information are supplied to the command information and print information separating circuit 84 provided on the head carriage 81. The command information separated by the separation circuit 84 is retained as it is in the setting command holding means 85 on the head carriage 81.
Is supplied to. Further, the set values and the like held by the holding means 85 are supplied to each circuit device and the like on the head carriage 81.

In the command information, for example, the above-mentioned (setting command for the number of print data to be transferred) +
(Setting parameter for the number of data transfers) is determined. Then, when this command information is discriminated, a control signal is supplied to the separation circuit 84, for example, switching is performed so that the data supplied to the separation circuit 84 is supplied to the error detection circuit 86 on the head carriage 81. Be seen.

Further, the error detecting circuit 86 detects an error in the transmitted print information by using the error detecting data added by the adding circuit 83. And
When no error is detected, the transmitted print information is directly supplied to the D / A converter 13 in the subsequent stage and converted into an arbitrary analog signal.

On the other hand, when an error is detected in the print information transmitted by the error detection circuit 86, a correction process is performed on the print information in which the error is detected. That is, in this correction process, for example, when print error is detected, the corresponding print information is replaced with blank data. Then, the print information on which the correction processing has been performed is supplied to the D / A conversion unit 13.

Further, the analog signal converted by the D / A converter 13 is supplied to the drive unit 15. In the drive unit 15, for example, a modulation signal in which the length of the period d to e in FIG. 7B and the potential change width are modulated is formed according to the level of the converted analog signal. Then, the modulation signal from the drive unit 15 is transmitted to the modulation unit 37 of the print head.
Is applied to

Further, the print control signal from the system bus 8 is supplied to the timing controller 18. Then, the pixel trigger signal from the timing control unit 18 is supplied to the timing control unit on the head carriage 81 through an arbitrary transmission path.
Supplied to 18A. And this timing control unit 18A
The D / A conversion trigger signal from is supplied to the D / A conversion unit 13, and the above-mentioned print information is analog-converted at the timing of this trigger signal.

Further, the timing control section 18 forms the ejection timing signal as shown in FIG. 7A, for example. The ejection timing signal is sent to the drive unit 38.
The ejection signal from the drive unit 38 is applied to the ejection unit 36 of the print head.

Further, in FIG. 5, only one nozzle of one print head is shown, but as will be described later, the nozzles of a plurality of print heads corresponding to each color of cyan, magenta, yellow, black, etc. When driving, the above D / A converters 13 to
A print head modulator 37, drive units 15 and 38, and a print head ejection unit 36 are provided.

Therefore, in the command information between the printer main body side and the head carriage 81, for example, (print mode designation command) + ([full-color high-quality / full-color plain paper / monochrome image / character] designation parameter ), (Print direction designation command) + (designation parameters such as [forward scan / reverse scan]), (effective nozzle designation command) + ([cyan / magenta / yellow /
A designation command such as a designation parameter of an effective nozzle such as [black]) is transmitted.

In this command information, for example, (modulation timing setting command) + (modulation signal output timing setting parameter for pixel trigger signal),
(Modulation waveform setting command) + (Modulation signal slope, pulse length setting parameter), (D / A conversion conversion reference value setting command) + (Cyan, magenta, yellow, black conversion reference value Setting commands such as setting parameters) are transmitted.

Further, in this command information, for example, (ejection timing setting command) + (ejection signal output timing setting parameter for the pixel trigger signal),
(Discharge waveform setting command) + (Discharge signal slope, pulse length setting parameter), (Effective gradation number setting command in one pixel) + (Gradation number setting parameter), and other setting commands are transmitted. It

In addition, in this command information, for example, (print range setting command in the main scanning direction) + (cyan,
Setting parameters for print start position and number of prints for magenta, yellow, and black heads), (error detection data method setting command) + (setting parameter), (error correction method setting command) +
A setting command such as (setting parameter) is transmitted.

Further, in this command information, setting commands such as (setting command for the number of print data to be transferred) + (setting parameter for the number of data transfers), (data transfer end command), (print operation end command), etc. are included. Is transmitted. Therefore, the print information to which the above-mentioned error detection data is added is transmitted after this (setting command for the number of print data to be transferred) + (setting parameter for the number of data transfers).

Then, the transmission of the print information is performed by the number set in the above (parameter for setting the number of data transfers). When the print information of the set number is further transmitted, the above (data transfer end command) is transmitted, and thereafter, the command information is transmitted again. The operation of transmitting the print information is performed in the same manner as between the host computer 150 and the printer device.

In FIG. 4, the motor drive trigger signal from the timing control unit 18 is supplied to the motor control unit 19. Further, a motor drive control signal from the system bus 8 is supplied to the motor controller 19. Then, the motor drive signal from the motor control unit 19 is supplied to the paper feed motor and the head feed motor 21 through the motor drive unit 20.

Further, for example, a position detection signal from the head position detection sensor 87 for detecting the position of the head carriage 81 is supplied to the system bus 8 through the sensor interface (I / F) 41, and the drive control of the head carriage 81 is performed. Be seen. Furthermore, the temperature detection signal from the temperature sensor 40 is
The signal is supplied to the system bus 8 through the sensor interface (I / F) 41, and the control and the like for the temperature change as described in, for example, Japanese Patent Application No. 7-254250 (which has been described above) are performed.

Therefore, in this apparatus, when transmitting print information having a number of bits smaller than the bit width of the transmission line, the print information is set on the MSB side of the transmission line and at the LSB side of the transmission line for error detection. By providing this data, it is possible to take a countermeasure against an error in the print information by an extremely simple means.

This eliminates the need to use, for example, a shielded cable, a shielded flat cable, a shielded flexible substrate, or the like which has been used as a transmission path for print information in a conventional apparatus.
An inexpensive cable can be used, and the head carriage can be moved smoothly by using a highly flexible cable.

Furthermore, since the problem of the print information transmission error is solved, the stability of the operation of the apparatus can be greatly improved.

In the above apparatus, the second bit on the LSB side of the transmitted print information is designated as "empty" to provide the designated data. You can predict when printing will be possible and leave it. Also, this 2 on the LSB side
A cyclic error correction code or the like may be provided using both of the bits.

The number of bits of the transmitted print information is not limited to the above 6 bits, and any number of bits can be applied as long as the number of bits is smaller than the bit width of the transmission path. In that case, the above-mentioned (setting command of effective gradation number in one pixel) + (setting parameter of gradation number) or (setting command of error detection data method) + (setting parameter), (error correction method The error detection circuits 3 and 83 on the receiving side are set using a setting command such as (setting command) + (setting parameter).

Further, in the above apparatus, the gradation expanding means such as the multi-gradation dither method (multi-gradation error diffusion method) is not limited to being provided on the host computer 150 side as described above. That is, for example, as a printer built-in type, in the printer body,
The 8-bit print information supplied to the data input / output interface circuit 4 is transferred to the CPU 5, ROM 6, R
A dither method or the like may be used by AM7 or the like, and the dither processing circuit section 88 shown by a virtual line in FIG. Then, in this case, the 6-bit print information can be transmitted to the head carriage 81 as described above.

By the way, the present applicant has developed a new method (carrier jet method) of quantifying one of the diluting liquid and the ink according to the print information and performing the halftone printing using the mixed liquid in which the other is mixed in a prescribed amount. A print head has already been proposed as Japanese Patent Application No. 7-254250 (filed on September 29, 1995).

FIGS. 5 and 6 show an example of the structure of a print head based on the carrier jet method, and FIG. 7 shows a waveform diagram of its operation.

In this print head 16, the substrate 55
The orifice plate is provided with a fixed amount side nozzle 50 for the ink 70 and a discharge side nozzle 51 for the diluent 71. An ink introducing hole 54 and a diluting liquid introducing hole 56 are connected to the nozzles 50 and 51, respectively.

Further, a fixed quantity side cavity (ink chamber) 60 and a discharge side cavity (diluting liquid chamber) 61 are provided on the rear side of these introduction holes 54 and 56, and a vibration plate 63 is provided in these cavities. It is provided. The diaphragm 63 is driven by an electrostrictive element (piezo element) 52 on the fixed amount side and an electrostrictive element (piezo element) 53 on the ejection side. Then, the drive signals as shown in FIGS. 7A and 7B are supplied to the fixed side electrostrictive element 52 and the discharge side electrostrictive element 53, respectively.

That is, FIG. 7A shows the electrostrictive element 53 on the ejection side.
An example of the drive signal supplied to the diluting liquid 71 of the diluting liquid introduction hole 56 is ejected from the ejection side nozzle 51 by giving a large displacement to the electrostrictive element 53 at the timing a. Further, at the timings of b and c, the electrostrictive element 53 is deformed (retracted) in the direction opposite to the above displacement, and the diluent 71 from the discharge side cavity 61 is introduced.
Is refilled.

FIG. 7B shows an example of the drive signal supplied to the electrostrictive element 52 on the fixed amount side. The ink 70 is pushed out from the fixed amount side nozzle 50 during the period of d to e. 70A is retained on the front surface of the discharge side nozzle 51. And
By ejecting the diluent 71 from the ejection side nozzle 51, the ejected diluent 71 is mixed with ink corresponding to the thickness (amount) of the retained ink 70A.

In this print head, the ejection timing (a) is, for example, 1 msec. Then, at this timing (a), for example, 0 to
A potential change of 20 V is applied, and the diluent is discharged by the displacement of the electrostrictive element 53 due to this potential change.

On the other hand, at timing (d), the electrostrictive element 52 on the fixed amount side is applied with a potential change of, for example, 0 to 10V. In this case, ink is not ejected by the displacement of the electrostrictive element 52 due to this potential change, and the ink 70A is discharged from the tip of the nozzle 50 by an amount corresponding to the potential change width and the pulse widths d to e.
Is only extruded.

Here, the amount of the ink 70A pushed out is controlled according to the length of the period of d to e and the potential change width, whereby the ink 70 retained on the front surface of the ejection side nozzle 51 is controlled.
The thickness of A can be controlled. Furthermore, this ink 70
The diluted liquid droplets 57 are discharged by ejecting the diluent 71 while being mixed with A. The ink density of the droplet 57 can be arbitrarily controlled by the ink amount 70A.

That is, d to e according to the above print information
The period and the potential change width of
It is possible to print with an arbitrary halftone by controlling such as 10 seconds, 10 V, 50 μsec, and 10 V. And in this case, the halftone to be printed will be
It is possible to obtain 64 different gradations.

However, in this case, for example, in the above-mentioned host computer 150 (see FIG. 4), print information is formed with 8 bits = 256 gradations. On the other hand, when the number of halftones printed by the printer device is small as described above (6 bits = 64 gradations), the so-called multi-gradation dither method (multi-gradation error diffusion method as an example) is used. A key magnifying means is used.

That is, for example, in the multi-gradation error diffusion method, as shown in FIG.
As illustrated in (A), an arbitrary pixel A forming an image
The level of is the level X '(usually 4, from the original desired level X (256 gradations) to be printed.
6, 8, 16, 32, 64 gradations, here 64 as an example
Gradation). In this case, the level X ′ to be replaced is set to the level closest to the level X, or the absolute value of the difference between the level X ′ and a plurality of possible levels X ′ is replaced as a probability. . In the latter method, level X'may be replaced by all possible levels.

Further, the error component ε between the level X and the level X ′ is
Is distributed to the pixels around the pixel A and added. In addition,
As shown in FIG. 2 (A), this distribution method is such that (7/16) ε for the pixel next to pixel A and 1 for the next scan line.
(3/16) ε for the previous pixel and (5/1) for the pixel immediately below
6) ε, and (1/16) for the pixel after the next scan line
The distribution method such as ε, or the probability of each distribution rate
There is a method of adding only to pixels.

The error ε has a sign of ±. Further, the error of the surrounding pixels to which the error is distributed is calculated by adding the distributed error. Further, when the value obtained by adding the distributed errors exceeds the maximum print level or the minimum print level of the printable range, the amount exceeding the maximum print level or the minimum print level is ignored or rounded or exceeded. The process of redistributing the minutes to the surrounding pixels by the same calculation as the above-described error amount ε with the above-described ratio or probability is performed.

As described above, by distributing the error component ε of the pixel A to the surrounding pixels, the printing error is diffused, and this is performed over the entire input image, and the image data to be printed is created. The gradation of the image obtained when the print information is printed can be substantially expanded (for example, 64 gradations can be expanded to 256 gradations). In addition, the numerical values such as the distribution ratio above are examples,
It can be variously changed according to the difference of the converted gradation, the range (number) of pixels to which the error is distributed, and the like.

Therefore, for example, by using the above-mentioned dither method or the like in the host computer, from the print information of 8 bits = 256 gradations formed by the host computer, for example, 64 gradations which can be printed by the above-mentioned printer device are displayed. Print information is formed. In this case, for example, the print information of 64 gradations is represented by 6 bits, for example. Further, in this dither method or the like, image data as shown in FIGS. 1 and 2B can be obtained.

FIG. 8 shows a specific structure of the print head 16 described above. That is, in FIG. 8, for example, print heads 16C, 16M, 16Y, and 16K for four colors (cyan C, magenta M, yellow Y, and black K) are provided, and each of these print heads is provided once. Nozzle having 24 electro-striction elements 52, 53 (e.g., cyan only, but not shown) for each of 24 cyan C, magenta M, and yellow Y, and 48 or 64 black K. 51, 52, 58 and 59 are provided in the head length direction.

Here, the black nozzles 58 and 59 are provided in the head length direction, and when printing a natural image, the nozzle 58 is used.
When printing characters, both nozzles 58 and 59 are used together to eject ink. The nozzles 58 and 59 may then be arranged as shown in phantom in FIG.
The driving method may be ink ejection by simply using a binary pulse, or may be a carrier jet method (black density control) in which nozzles are arranged as described above. When the nozzles 58 and 59 are used together, the partition wall 55a between the ink chambers may be removed so that the ink chambers communicate with each other.

Then, the electrostrictive elements 52, 53, etc. are driven by the above-mentioned modulation signal and ejection signal, whereby ink droplets having a density corresponding to the gradation of print information are ejected. Note that, for example, 24 droplets of cyan C, magenta M, and yellow Y are ejected from this droplet, and black K is ejected.
48 or 64 droplets are discharged simultaneously for each color and at a predetermined timing between the colors.

Furthermore, these print heads 16C, 16
When driving M, 16Y, and 16K, the number of D corresponding to the number of nozzles for each of these printheads is increased.
/ A converter 13 to print head modulator 37 and drive unit
15, 38 and the print head ejection unit 36 are provided, for example, as shown in FIG. 3 or FIG. However, for 16K for black, in the case of binary pulse driving, the circuit configuration shown in FIG. 11 described later may be adopted.

FIG. 9 shows an example of a serial type printer device incorporating the above-mentioned print head. According to this printer device, the recording paper 180 is mounted on the platen.
Wrapped around 91 weeks and transported. This platen 91
Is rotatably driven by a paper feed motor 92 (a part of the motor 21 in FIG. 4) via pulleys 93, 94 and a belt 95.

The print head 16 including the electrostrictive elements 52, 53 and the like is provided on the head carriage 81,
The head carriage 81 is attached to a feed screw 96 provided parallel to the peripheral surface of the platen 91. This lead screw 96
Is driven by a head feed motor (not shown), the print head 16 on the head carriage 81 is moved in parallel to the peripheral surface of the platen 91.

Then, for example, according to print information 97 from the host computer 150 (see FIG. 4), transmission signals such as print information for transmission, command information, pixel trigger signals, and control signals 98 for head feed control, paper feed control, etc. Is formed. Further, these transmission signals are transmitted to the head carriage 81.
And the control signals are supplied to a head feed motor (not shown), a paper feed motor 92, etc., and printing according to the print information 97, transfer of the recording paper 180, and scanning of the print head 16 are performed. Done.

Further, in this apparatus, a tongue piece 99 is provided on the head carriage 81, and this tongue piece 99 is detected by the position detection sensor 87 provided on the movement path of the head carriage 81. Thus, for example, when the normal scanning is not performed, it is detected that the head carriage 81 has returned to the home position shown by the broken line.

FIG. 10 shows an example of a line type printer device. In this case, instead of the serial type printer head 16 and the feed screw 96 shown in FIG. 9, a line head 16A having a large number of heads arranged in a line is fixedly provided in the axial direction of the platen 91. .

In this example, since the line head 16A has a large number of sets of heads as shown in FIG. 8 arranged in the axial direction of the platen 91, its detailed structure will not be described here, but FIG. And the circuit shown in FIG. 4 simultaneously prints one line, and when printing is completed, the platen 91
Is rotated by one line to perform the next printing (16 in the figure)
0 is a paper pressure roller, but this can also be used for the printer of FIG. 9). In this case, all lines can be printed at once, divided into a plurality of blocks, or alternately printed every other line. Others are the same as those described in FIG.

11 to 14 show another embodiment of the present invention.

This embodiment relates to a printer of a normal type other than the above-mentioned carrier jet system. First, the construction of the print head 16B will be described with reference to FIGS. This print head uses a piezo element 52 as an electrostrictive oscillator that causes electrostriction (a phenomenon that causes deformation or distortion when an electric field is applied to a dielectric). For example, a so-called ink dot diameter modulation method may be used. It is possible to obtain the halftone print of No. 2 and to correct the change in the ink droplet ejection characteristics due to the change in the temperature of the head and the change in the ambient environment temperature as described later.

In the ink dot diameter modulation method, the voltage level applied to the electrostrictive vibrator 52 of the print head 16B is changed according to the data of the image to be printed, and the applied voltage level is changed. The electrostrictive oscillator 52 is displaced so that the volume of the ink droplets ejected from the nozzle 161 is adjusted by the electrostrictive oscillator 52.
The nozzle 161 by changing it according to the displacement of
In this method, the diameter of the ink dot formed by the ink droplets ejected from the recording paper 180 adhering to the recording paper 180 is changed to obtain a desired halftone print.

As described above, the print head 16B using the above-mentioned ink dot diameter modulation method for quantifying the volume of the ejected ink droplet is a flat plate made of piezoelectric ceramics which is displaced in the direction of arrow SD in FIG. 13 according to the applied voltage. Type electrostrictive oscillator 52, a vibrating plate 63 adhered to the electrostrictive oscillator 52, a nozzle unit 164 including the electrostrictive oscillator 52 and the vibrating plate 63, and a substrate inside the nozzle unit 164. Ink chamber 170 provided between 55 and diaphragm 63
Ink supply port for supplying ink 70 filled in 170 1
70a, a nozzle 161 for ejecting the ink 70 as an ink droplet 167 (see FIG. 14) and an orifice portion 169, and a voltage generator (not shown) for generating a voltage applied to the electrostrictive oscillator 52. Have

The volume change in the ink chamber 170 caused by applying a voltage corresponding to the image data to be printed from the voltage generator to the electrostrictive vibrator 52 causes
It is configured to eject ink droplets 167.

The print head 16B has a multi-color multi-nozzle (16B (Y) for magenta, 16B (M) for magenta, 16B for cyan) having a structure as shown in FIGS.
(C), 16B (K) for black are applied. That is, the print head of this multi-nozzle configuration
As shown in FIG. 14, 16B is provided with electrostrictive oscillators 52 corresponding to a large number of nozzles, respectively, and by applying a voltage to each of these electrostrictive oscillators 52, ink is ejected from each nozzle 161. Droplet 167 is adapted to be ejected.

The material of the electrostrictive oscillator 52 is the same as in the above-mentioned embodiment, but a piezoelectric material made of lead zirconate titanate (PbTiO ₃ .PbZrO ₃ ) or barium titanate (BaTiO ₃ ). There are ceramics, crystal, Rochelle salt, etc. Further, the present invention is not limited to the multicolored printheads each having a multi-nozzle as shown in FIG. 14, but an inkjet printhead having a single monochromatic nozzle and an inkjet printhead having a multicolored single nozzle. The present invention can be applied to any of inkjet print heads having a single-color multi-nozzle.

Further, in the print head of this example, when the diameter of the ink dot formed on the recording paper does not sufficiently correspond to the change in the voltage level applied to the electrostrictive vibrator 52 (that is, the above-mentioned ink dot diameter modulation). If sufficient gradation reproduction is not possible with only the method), in addition to the ink dot diameter modulation method, combine the gradation reproduction ink dot arrangement method corresponding to the gradation order that can be realized by this ink dot diameter modulation method. As a result, sufficient gradation reproduction can be realized.

More specifically, for example, the ink dot diameter modulation method is used in the range where stable gradation reproduction is possible by the ink dot diameter modulation method, but gradation reproduction is unstable by the ink dot diameter modulation method. In such a range, the gradation reproduction method based on the arrangement of ink dots is used. That is,
As an example of the case where stable gradation reproduction is impossible, for example, the gradation reproduction method by the arrangement of ink dots is used in the highlight part of the image, and the original ink dot is formed in the middle to the shadow part excluding these highlight parts. Use the diameter modulation method.

Alternatively, it is also possible to use the above ink dot diameter modulation method and the gradation reproduction method corresponding to the number of gradations obtained by this modulation method in combination for all gradations.
Examples of this tone reproduction method include the random dither method and the systematic dither method, which are independent decision methods, and the average error minimum method, error diffusion method, mean value restriction method, and dynamic threshold method that are conditional decision methods. Law etc. are mentioned.

By the way, in the print head having the multi-nozzle structure as described above, the ejection characteristics of the ink droplets are changed due to the temperature change of the print head and the environmental temperature change of the surroundings. In some cases, the actual resolution is lowered, and the printing gradation level becomes inaccurate, which makes it impossible to print with uniform quality.
In addition, variations in temperature may cause variations in the ejection characteristics of the ink droplets of the individual nozzles.

Therefore, in this example, a temperature sensor 40 (see FIG. 11) such as a thermistor is provided near the orifice 169 of the print head 16B, and the temperature sensor changes the temperature of the print head 16B and the surrounding environment. A temperature change is detected, and based on the value of the detected temperature change, the temperature change affects the ejection characteristics of the print head and cancels the influence on the ink dot diameter on the recording paper.
The content of the image data to be printed at the beginning is changed. Thus, in this example, by changing the content of the original image data based on the detected value of the temperature change,
This makes it possible to realize halftone printing that is not affected by changes in the print head temperature during use and environmental temperature changes.

It should be noted that the present invention is not limited to the case where both the temperature of the print head and the change in the ambient temperature around the print head are detected, but only one of these factors is detected and the image data is changed based on the detected one. However, it is possible to perform halftone printing that is not easily affected by temperature changes.

Next, the configuration and operation of the printer of this example will be described with reference to FIG. In addition, this configuration and operation
Compared to that shown in FIG. 3, the carrier jet method is not used, and only the ink of a previously adjusted concentration is ejected without providing the diluent ejecting section and its drive section. Descriptions of similar parts are omitted.

That is, as described with reference to FIG. 3, the print data signal from the RAM 7 is converted by the D / A converter 13 into a head drive signal of a voltage level used for actual printing,
This head drive signal is sent to the head drive unit 15.

In the head drive section 15, the head drive signal is amplified to the electric power necessary for displacing the electrostrictive vibrator of the print head 16, and the amplified signal is used as a head applied signal for electrostriction of the print head 16B. Send to oscillator.

In the print head 16B, the electrostrictive vibrator 52 shown in FIG. 13 is displaced in the direction shown by the arrow SD according to the voltage level of the head applied signal, and the diaphragm 63 is pushed and bent.
As a result, the volume in the ink chamber 170 is reduced, the ink 70 filled in the ink chamber is pressed, and the nozzle 16
Ink droplets 16
It flies to the recording paper as 7.

The ink droplet 167 forms an ink dot having a certain dot size on the recording paper. This ink dot has a size corresponding to the voltage level applied to the electrostrictive oscillator 52.

Although the embodiments of the present invention have been described above, the above-mentioned embodiments can be variously modified based on the technical idea of the present invention.

For example, the types of image data described above may vary, and the output method and timing thereof are not limited to those described above. The timing, the number, and the like of the dot data for which ink is not ejected in the image data may be variously changed. The dither method is not limited to the one described above.

Further, in the above-mentioned example, the so-called carrier jet structure, in which the ink is quantitatively discharged and the diluting liquid is ejected, is used instead of the so-called carrier jet structure. Also, the same effect as the above example can be realized. In the latter case, a sufficient ink density can be obtained for the shadow portion, which is advantageous.
Further, black (K) may be ejected alone without being mixed with the diluting liquid.

The above examples are suitable for recording an image, but when printing only characters, it is not always necessary to obtain a halftone, so the above-described ink ejection is performed by binary control. Good.

Each of the above-mentioned inks and diluents may be selected from known ones and used. Also, magenta,
Three colors, yellow and cyan (plus black)
In addition to full-color recording, two-color printing, one-color printing in mono-color or black and white can be performed.

As the energy for forming the recording material into droplets, a heating method such as resistance heating (see FIG. 17) or irradiation of a heating beam such as laser light may be used instead of the electrostrictive element. To improve the heating efficiency, a conductive material can be added to the recording material. Although a heating element and a laser can be combined for heating, in this case, good recording can be performed even if the power of each heating means is lowered.

The structure and shape of the head may be any suitable structure and shape other than those described above, and known materials may be selectively used as the material of each part constituting the head.

The inkjet printers to which the present invention can be applied include (I) an on-demand type inkjet printer and (II) a continuous type inkjet printer depending on the method, and in terms of function, (1) a binary printer (2) There is a halftone printing printer, and further, as the halftone printing printer, there are (a) dot diameter modulation printer and (b) density modulation printer (including a so-called carrier jet type of two liquid mixture type).

[0184]

As described above, according to the present invention, when recording is performed with a large number of dots based on the recording data, a plurality of dots of these recording dots are formed in a region where they are successively formed at a predetermined density or more, except for the specific dots. Since only the recording of is performed, when one pixel is formed,
The recording material adheres to the recording material such as recording paper, and immediately after this, recording is not performed as a specific dot position. Therefore, the recording material on the recording material is fixed and the next adjacent position (or Even if another recording material is attached to the same position) to form the next pixel, these recording materials do not interfere with each other.

Therefore, the recording material on the recording medium can be suppressed from bleeding and mixing to the minimum, the color reproduction characteristics can be improved, high image quality can be obtained, and the resolution can be improved. can get.

Also, for example, when no dedicated recording paper is used as the recording medium, when the environmental temperature at the time of printing or printing is low, or when high speed head scanning is performed,
Since the above-mentioned remarkable effects can be obtained, it is possible to use recording paper at low cost, which is advantageous in terms of cost, and is also advantageous in terms of use and operation.

[Brief description of drawings]

FIG. 1 is a waveform diagram of print data on a print head of an inkjet printer according to the present invention.

FIG. 2 is a diagram for explaining a multi-gradation error diffusion method when printing with the same head.

FIG. 3 is a block diagram of a circuit for operating an inkjet printer device according to the present invention.

FIG. 4 is a more detailed block diagram of the circuit.

FIG. 5 is a cross-sectional view of an example of a printhead of an inkjet printer according to the present invention.

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is a waveform diagram for operating the same print head.

FIG. 8 is a schematic perspective view of a specific example of the print head.

FIG. 9 is a schematic perspective view of a serial type ink jet printer device incorporating the same print head.

FIG. 10 is a schematic perspective view of a line-type inkjet printer device.

FIG. 11 is a block diagram of a circuit for operating another inkjet printer device according to the present invention.

FIG. 12 is a cross-sectional view of a print head used in the printer device.

13 is a sectional view taken along line XIII-XIII in FIG.

FIG. 14 is a schematic perspective view of a specific example of the print head.

FIG. 15 is a schematic partial cross-sectional front view of a conventional thermal transfer type printer device.

FIG. 16 is a schematic cross-sectional view showing a state of ink ejection by a print head of various conventional inkjet printers.

FIG. 17 is a schematic cross-sectional view for explaining ink ejection by a print head of another conventional inkjet printer.

FIG. 18 is a schematic plan view for explaining a situation in which an image is printed by scanning a print head of a conventional inkjet printer.

FIG. 19 is a diagram for explaining a multi-gradation error diffusion method at the time of printing by the print head.

FIG. 20 is a waveform diagram of print data for the print head.

[Explanation of symbols]

4 ... Data input / output interface (I / F) circuit, 5 ...
CPU, 6 ... ROM, 7 ... RAM, 13 ... D / A converter,
15, 38 ... Drive unit, 16, 16A, 16B ... Print head, 17, 87 ... Head position detection sensor, 18, 18A ... Timing control unit, 19 ... Motor control unit, 20 ... Motor drive unit, 21 ... Paper feed motor And head feed motor, 36 ... Print head ejection unit, 37 ... Print head modulation unit, 40 ... Temperature sensor, 41 ... Sensor interface (I / F), 5
0, 51, 58, 59, 161 ... Nozzle, 52, 53 ... Electrostrictive element, 5
7, 167 ... Droplet, 60, 61 ... Cavity, 63 ... Vibration plate, 70
... Ink, 71 ... Diluent, 81 ... Head carriage, 82 ... Command information and print information combination circuit, 83 ... Error detection data addition circuit, 84 ... Command information and print information separation circuit, 85 ... Setting command holding Means 150 Host computer 152 Interface I / F circuit 180 Recording paper 181 Image data

Claims (12)

[Claims] 1. When printing is performed with a large number of dots based on print data, only a specific dot is printed in an area where a plurality of these print dots are sequentially formed at a predetermined density or higher. Recording method. 2. The recording method according to claim 1, wherein when a recorded image composed of a large number of recording dots has a continuous spread at a predetermined density or more, recording is not performed on specific dots existing at regular intervals. 3. The recording method according to claim 1, wherein a large number of dots are recorded by a multi-gradation dither method for obtaining a recorded image having gradation. 4. The recording method according to claim 3, wherein recording data of specific dots which are not to be recorded is distributed to the dots around them. 5. When ink droplets are deposited on a recording medium by an ink jet method to perform recording, bleeding of the ink deposited on the recording medium and mixing of adjacent inks start to occur. The recording method according to claim 1, wherein ink droplets are not ejected for specific dots that are present at regular intervals in a region where a large number of recording dots are formed with a minimum density or higher. 6. The recording method according to claim 5, wherein recording is performed by mixing the quantified ink and the ink diluent and adhering them as recording droplets in a dot shape on the recording medium. 7. A data input unit for obtaining print data capable of printing only a specific dot in an area where a plurality of these print dots are sequentially formed at a predetermined density or higher when printing is performed with a large number of dots. A recording apparatus including a signal conversion unit that converts the recording data into a recording head drive signal, a drive unit that modulates and drives the recording head by the conversion signal, and a recording head. 8. The recording apparatus according to claim 7, wherein when a recorded image formed by a large number of recording dots has a continuous spread at a predetermined density or more, recording is not performed on specific dots existing at regular intervals. 9. The recording apparatus according to claim 7, wherein recording of a large number of dots is performed by a multi-gradation dither method for obtaining a recorded image having gradation. 10. The printing apparatus according to claim 9, wherein print data for specific dots that are not printed is distributed to dots around the dots. 11. When ink droplets are deposited in a dot shape on a recording medium by an inkjet method to perform recording, bleeding of the ink adhering to the recording medium and mixing of adjacent inks start to occur. The recording apparatus according to claim 7, wherein ink droplets are not ejected for specific dots that are present at regular intervals in a region where a large number of recording dots are formed at a minimum density or higher. 12. The recording apparatus according to claim 11, wherein recording is performed by mixing the quantified ink and the ink diluent and adhering them as recording droplets in a dot shape on the recording medium.