JPH06328678A - Ink jet recording apparatus and method and recorded matter - Google Patents

Abstract

PURPOSE:To make a granular feel sufficiently inconspicuous even when the kinds of dark and light inks are few and to enable recording excellent in gradation properties by emitting inks different in density and different in the permeability on a recording medium from at least two of ink emitting means. CONSTITUTION:A dark ink head 12A and a light ink head 12B are arranged side by side and the recording heads thereof have emitting orifice surfaces 1 having a plurality of emitting orifices 2. Emitting energy generating elements 4 generating energy necessary for emitting ink are respectively arranged to the passage parts 3 communicating with the emitting orifices 2. An arrow (y) shows the scanning direction of a carriage. The diode sensors 5 for detecting the temp. of each of recording heads are provided on both sides of emitting orifice rows. A temp. detection means is not especially limited to a diode sensor and other sensor such as a thermistor may be used.

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, an ink jet recording method and a recorded matter for recording by discharging dark and light ink onto a recording medium.

[0002]

2. Description of the Related Art In a conventional ink jet recording system, ink is ejected from a plurality of ink ejection openings formed in a recording head based on a data signal, and ink droplets are attached to a recording material such as paper for recording. ing. This recording method is used, for example, in printers, facsimiles, copiers, and the like.

In the above apparatus, in order to eject the ink, a heating element (electrical / thermal energy converter) is provided in the vicinity of the ejection port, and an electric signal is applied to the heating element to locally heat the ink. There are a method of using an electrical / thermal energy converter that causes a pressure change and ejects ink from an ejection port, and a method of using an electrical / mechanical converter such as a piezoelectric element.

In this type of recording method, a dot density control method is used in which the number of recording dots per unit area is controlled by recording dots of a fixed size to express a halftone, or the size of recording dots is controlled to express a halftone. The halftone recording control is performed by the dot diameter control method.

Here, the latter dot diameter control method is limited because complicated control for subtly changing the size of the recording dot is required, so the former dot density control method is generally used. Has been.

In addition, as an ink ejecting means, it is easy to manufacture, and high density is possible.
When the thermal energy converter is used, it is difficult to control the amount of pressure change and the diameter of the recording dot cannot be modulated, and therefore the dot density control method is used.

The systematic dither method is one of the typical halftone expression binarization methods used in the dot density control method, but this method has a problem that the number of gradations is limited by the matrix size. There is. That is, it is necessary to increase the matrix size in order to increase the number of gradations, but if the matrix size is increased, there is a problem that one pixel of a recorded image formed by one matrix becomes large and the resolution is impaired. It was Another typical binarization method is a conditional decision type dither method such as an error diffusion method. This is an independent decision type dither method in which the systematic dither method described above is binarized by using a threshold value unrelated to the input pixel, whereas the threshold value is changed in consideration of the peripheral pixels of the input pixel. Is the way. The conditional decision type dither method typified by this error diffusion method has good compatibility of gradation and resolution, and when the original image is a printed image,
Although it has the advantage that a moire pattern is rarely generated in the recorded image, it has a problem that the graininess is easily noticeable in the bright areas of the image and the image quality is poorly evaluated. This problem was particularly remarkable in a recording device having a low recording density.

Therefore, in order to make the above-mentioned graininess inconspicuous, the conventional ink jet recording apparatus is provided with two recording heads for respectively ejecting light-colored ink and dark-colored ink, and from the light portion to the halftone portion of the image. A recording method has been proposed in which recording dots are formed with light-colored ink and recording dots are formed with dark-colored ink from the halftone portion to the dark portion. By using the multi-valued light and shade recording method using a plurality of light and shade inks of different densities for the same color, the gradation property of the highlight part is particularly improved even if the binary value is changed to the ternary value. It is possible to improve the image quality. This is because the noise feeling of a single dot is eliminated by hitting a low density (light) ink to the highlight part.

[0009]

However, this multi-valued dark / light multi-valued recording method can eliminate the graininess by increasing the number of types of dye density of the dark / light ink, but by increasing the number of types, the recording head There is a problem that the number of ink tanks and the number of ink tanks increase, the carriage for mounting them also increases, and the apparatus itself increases in size. Such a restriction is particularly great in a color recording apparatus, and even with the method described above, the graininess in the highlight part cannot be sufficiently reduced, and the difference in dot density between dark and light inks of color is large. In this case, there is a problem that gradation reproduction is not linear at the switching portion between the light ink and the dark ink.

Therefore, the present invention has been made in view of the above problems, and an ink jet recording apparatus and an ink jet recording apparatus which can make a recording excellent in gradation by making the graininess sufficiently inconspicuous even with a small number of dark and light inks. The purpose is to provide a recording method and a recorded matter.

[0011]

In order to achieve the above object, the present invention is an ink jet recording in which an image is formed by ejecting ink onto a recording medium using a plurality of ink ejecting means capable of ejecting a plurality of inks having different densities. The apparatus is characterized in that at least two of the ink ejecting means eject inks having different densities and penetrating properties on a recording medium.

Further, according to the present invention, there is provided an ink jet recording method for forming an image by adhering a plurality of inks having different densities to a recording medium, wherein inks having different densities and different penetrability on the recording medium are adhered to the recording medium. An ink jet recording method is provided, which comprises forming an image.

Further, according to the present invention, there is provided a recorded matter in which an image is formed on a recording medium by using a plurality of inks having different densities and different penetrability on the recording medium.

[0014]

According to the present invention, an image is formed by attaching inks having different densities and different penetrability on the recording medium to the recording medium. As a result, an image having no gradation and excellent gradation is formed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment to which the present invention is applied will be concretely described with reference to the drawings.

(First Embodiment) FIG. 1 is a perspective view showing the essential structure of a color ink jet recording apparatus according to the first embodiment of the present invention.

The recording head 12A having an ejection port array for ejecting dark color ink and the recording head 12B having an ejection port array for ejecting light color ink are installed on the carriage 23 at a predetermined distance.

A recording material P made of paper, a thin plastic plate, or the like is sandwiched by a paper discharge roller 21 via a transport roller (not shown), and is fed in the direction of an arrow when a transport motor (not shown) is driven.

A carriage 23 is guided and supported by a guide shaft 22 and an encoder (not shown).

The carriage 23 is reciprocated along the aforementioned guide shaft 22 by driving a carriage motor 25 via a drive belt 24.

A heating element (electrical / thermal energy converter) that generates thermal energy for ejecting ink is provided inside the ink ejection port (liquid path) of the recording head.

In accordance with a reading timing of an encoder (not shown), the heating element is driven based on a recording signal to eject and deposit ink droplets on the recording material P in the order of dark ink color and light ink color. An image can be formed with.

A recovery unit having a cap portion 26 is arranged at the home position (HP) of the carriage selected outside the recording area. When recording is not performed, the carriage 23 is moved to the home position (HP), the ink ejection port forming surface of the corresponding recording head is sealed by each cap of the cap unit 26, and the ink is fixed or dust is generated due to the evaporation of the ink solvent. Prevents clogging due to foreign matter such as adhesion.

Further, the capping function of the cap portion is an idle ejection for ejecting ink to the cap portion 26 which is away from the ink ejection port in order to eliminate ejection failure and clogging of the ink ejection port which is infrequently recorded. It is used for a mode or for operating a pump (not shown) in a capped state to suck ink from the ink ejection port and recover the ejection from the ink ejection port that has caused ejection failure. Further, by disposing the blade and the wiping member at the position adjacent to the cap portion, it is possible to clean the ink ejection port forming surface of the recording head.

FIG. 2 is a schematic perspective view of the ink discharge port array of the recording head 12 as seen from the recording material side.
2 is moved in the scanning direction indicated by y in the figure. FIG. 3 is a partial perspective view schematically showing the structure of the ink ejection portion. This is one in which a dark ink head 12A and a light ink head 12B are arranged in parallel, and each recording head has an ejection port surface 1 having a plurality of ejection ports 2 opened, and communicates with the ejection port 2. Ejection energy generation elements 4 that generate the energy required to eject ink are arranged in the liquid path portion 3. The arrow y indicates the scanning direction of the carriage 23. Reference numeral 5 in FIG. 3 is a sensor for detecting the temperature of the recording head. In this embodiment, diode sensors 5 are provided at both ends of the ejection port array. The temperature detecting means is not particularly limited to this, and another sensor such as a thermistor may be used, or a method of calculating the head temperature from the duty of the print dot may be adopted.

FIG. 4 is a block diagram showing the arrangement of the color ink jet recording apparatus in this embodiment.

In FIG. 4, reference numeral 41 denotes an image input section for optically reading an original image by a CCD or the like or for inputting an image brightness signal (RGB) from a host computer, a video device or the like, and 42 indicates setting and printing of various parameters. 3 shows an operating unit with various keys to support the start. Reference numeral 43 denotes a CPU which controls the entire recording apparatus according to various programs in the ROM. Reference numeral 44 denotes a ROM which stores a program for operating the recording apparatus according to the control program / error processing program. In this ROM, 44a is an input gamma conversion table for reference in the processing of the input gamma conversion circuit, 44b is a masking coefficient referred in the processing of the color correction (masking) circuit, 44c is referred in the processing of the black generation and UCR circuit. A black generation and UCR table, 44 is a density distribution table for reference in the processing of a density distribution circuit described later, and 44e is a program group that stores the various programs described above. 45 is RO
A RAM used as a work area for various programs in M and a temporary save area during error processing is shown.
Reference numeral 46 denotes a processing unit that performs image signal processing described later, and 47 denotes a printer unit that forms a dot image based on the image signal processed by the image signal processing unit during recording. Reference numeral 48 denotes a bus line for transmitting address signals, data, control signals and the like in this device.

Next, the image signal processing section will be described.

FIG. 5 shows a block diagram of the image signal processing system. The image processing circuit 51 includes masking and UCR (= Un
der Color Removal) processing and the like, and any general image processing flow is applicable.

Now, the monochromatic data after the color processing is taken into the next gradation distribution processing circuit 52. Here, the input / output data is divided into light ink data and dark ink data by the light / dark distribution table 44d.

FIG. 6 shows an example of the conversion graph of the gradation distribution table. Here, the solid line corresponds to the light ink data, and the dashed line corresponds to the dark ink data. If the value of 8-bit single color data is in the range of 0 to 128, the dark ink data is "0", and the light ink data is Is output in the range of "0 to 255", and if the value of the single color data is in the range of 128 to 255, the dark ink data corresponds to "0 to 255" and the light ink data corresponds to "255 to 0". To output. In short, in this embodiment, when the input data is low (highlight side), the ink having a low dye concentration (light ink) is mainly used, and when the input data is high, the ink having a high dye concentration is used for recording. It was done like this.

By changing the solvent composition of the ink jet ink, it is possible to change the spread of dots when ink droplets are ejected onto a recording medium such as plain paper such as copy paper or bond paper and land.

Generally, a dot having a small spread has a high density of the dot itself and is suitable for obtaining a sharp image, but the penetrating speed into paper tends to be slow. On the other hand, in the case where the dot spread is large, the dye diffuses and the density of the dot itself is low, resulting in an overall blurred image, which is suitable for obtaining a halftone image.

Next, an example of the ink composition used in this example is shown.

Composition (example of ink composition with small spread of dots) Dye 0.5 to 5 wt% Glycerin 7.5 wt% Thiodiglycol 7.5 wt% Urea 7.5 wt% Pure water balance

This kind of ink has good character quality with respect to so-called plain paper such as copy paper and bond paper. Generally, the ink for inkjet is η / (γ
It is said that the smaller the value of cos θ), the faster the penetration of ink into paper. Here, η is the viscosity of the ink, γ is the surface tension of the ink, and θ is the contact angle between the ink and the paper. Generally, when the contact angle is made small, the wettability of the ink with respect to the paper is increased, and the penetration into the paper can be accelerated, but the ink is apt to spread on the paper surface, the dot sharpness is lacked, and the printing quality is deteriorated. In order to improve the printing quality, it is better to lower the wettability to paper, but on the contrary, the penetrability is reduced. The ink of the above composition has a surface tension of 40.
Approximately 50 to 50 dyne / cm, which is a class of high surface tension for ink, the ink spreads on the paper surface by reducing the penetrability into the paper in consideration of the balance with the fixing property, resulting in uneven fiber fibers. This prevents bleeding along the line (feathering phenomenon) and improves the printing quality.

Composition (ink composition example with large spread of dots) Dye 0.5 to 5 wt% Glycerin 7.5 wt% Thiodiglycol 7.5 wt% Acetylene glycol EO adduct (N = 10 5 wt% Urea 7.5 wt% Pure Water balance EO: ethylene oxide

This kind of ink has a very fast fixing property to plain paper such as copy paper and bond paper, and in color recording, even if ink recording areas of different colors are adjacent to each other, improper color mixture ( The feature is that there is no bleeding or bleeding at the boundary and uniform coloring (less color unevenness) is possible.

In order to spread the dots, it is effective to make the contact angle θ small so that the ink can be very wet with the paper. Generally, a surfactant is used to improve the wettability. In the case of the composition ink, the surface tension is about 30 dyn due to the addition of the nonionic surfactant.
Although it is as small as / cm, it has good wettability with respect to paper, is easy to spread on the surface of the paper (large dots), and has excellent penetrability. However, since the dots spread widely, the sharpness is lacking and the density of the dots themselves is lower than that of the ink having the above-described composition.

FIG. 7 and FIG. 8 conceptually show the difference between the ink composition when the dye concentration is the same and the dot difference on the paper when the ink composition is used. FIG. 7 shows the case of the ink composition, in which the dots do not spread, but the print density of the dots themselves is high, so that the contrast with the paper is clear and there is a graininess. However, as shown in FIG. 8, in the case of the ink composition, the dots tend to spread, so the dye that is the coloring material also spreads overall, the density of the dots themselves becomes low, the contrast is small, and the graininess can be considerably reduced. .

9 and 10 conceptually show the ink composition and the character quality when the ink composition is used. FIG. 9 shows the case of the ink composition, and FIG. 10 shows the case of the ink composition. As for the ink composition, the character quality is very sharp and good, whereas the ink composition has a thick and dull appearance as a whole.

In this embodiment, the dark ink has an ink composition and the light ink has an ink composition. With this configuration, dark ink that often records characters, thin lines, etc. can be recorded in good quality with sharpness.
Then, the light ink used for halftone recording and particularly for recording the highlight portion is made to be ink in which dots spread, so that the granular feeling in the highlight portion can be made inconspicuous. In addition, the graininess that occurs when the difference in dot density between the dark and light inks at the switching portion of the dark ink and the light ink is large, in this embodiment, when the light todd and the dark todd contact, the dark todd also occurs. As it spreads toward the light todd recording portion, the density difference becomes small and becomes inconspicuous. This is because the light ink contains a surfactant, so that the light todd recording area is easily wetted by the surfactant, and the dark ink todd in contact with the light ink also spreads easily. Conceivable.

Further, the way the dark ink todd spreads at this time may change depending on the order in which the dark ink and the light ink are ejected. This is because in this embodiment, when the dark ink is ejected, the light ink is ejected immediately after that, but since the dark ink has low permeability, the light ink is ejected before the dark ink is sufficiently fixed. The ink is easily mixed on the paper surface because the ink is hit. On the other hand, when light ink with fast penetrability is first ejected and then dark ink with slow penetrability is ejected, the light ink penetrates the paper more quickly, so it is hard to mix on the paper surface, and the bleeding is slightly eased. . Since this also changes depending on the combination of ink compositions, it is preferable to determine the order in which the dark and light inks are ejected in consideration of them.

As the penetrant used for the light ink, an anionic surfactant such as aerosol OT type, sodium dodecylbenzenesulfonate and sodium lauryl sulfate, or ethylene oxide addition of a higher alcohol represented by the following general formula [1] is used. , An ethylene oxide adduct of an alkylphenol represented by the following general formula [2], an ethylene oxide-propylene oxide copolymer represented by the following general formula [3], an acetylene glycol represented by the following general formula [4] Non-ionic surfactants such as ethylene oxide adducts are excellent.

However, the above-mentioned anionic surfactant has a large bubble force, is inconvenient to handle, and has image characteristics such as boundary bleeding, color uniformity, and feathering, which are better than those of the anionic surfactant. Since the nonionic surfactant is better, the nonionic surfactant represented by the following general formula was used in the present invention.

[0046]

[Outer 1]

Among the ethylene oxide-type nonionic surfactants mentioned above, ethylene oxide adducts of acetylene glycol are absorbed in the ink absorber, image characteristics on the recording medium, ejection characteristics from the recording head, etc. It has a very good balance and is preferable. Furthermore, the hydrophilicity and permeability of this compound are controlled by the number N of ethylene oxide added. When N is less than 6, the permeability is good, but the water solubility is poor and the solubility in ink is poor. On the contrary, if the number of ethylene oxide added is too large, the hydrophilicity becomes too large and the penetrating power becomes small. When N is larger than 14, the permeability is lowered, and it cannot be said that it is effective only by increasing the addition amount, but rather it causes a bad influence on the ejection characteristics. Thus, this compound has an ethylene oxide addition number of 6 to 14
Is preferably between

The amount of these nonionic surfactants added is preferably 0.1 to 20% by weight. If it is 0.1% or less, the image characteristics and penetrability are not sufficient, and if it is 20% or more, no further effect can be obtained.
This is because the reliability of the ink is disadvantageous.

Further, one or more of these nonionic surfactants may be combined.

In addition to the above, the ink components generally include a dye as a recording agent, a low-volatile organic solvent such as a polyhydric alcohol for the purpose of preventing clogging, foaming stability and fixability on a recording medium. The desired organic solvent such as alcohol is added as necessary.

Examples of the water-soluble organic solvent forming the ink of the present invention include polyalkylene glycols such as polyethylene glycol and polypropylene glycol; ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexane. Alkylene glycols having an alkylene group of 2 to 6 carbon atoms such as triol, hexylene glycol and diethylene glycol; glycerin; ethylene glycol methyl ether, diethylene glycol methyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl)) ether Lower alkyl ethers of polyhydric alcohols such as; methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl Alcohols such as rucohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, benzyl alcohol, cyclohexanol; amides such as dimethylformamide, dimethylacetamide; ketones or ketone alcohols such as acetone and diacetone alcohol; tetrahydrofuran , Ethers such as dioxane; nitrogen-containing cyclic compounds such as N-methyl-2-pyrrolidone, 2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone. These water-soluble organic solvents can be contained in an amount that does not deteriorate image characteristics and ejection reliability. Polyhydric alcohols and alkyl ethers of polyhydric alcohols are preferable, and the content thereof is desirably 1 to 30% by weight.

At this time, the amount of pure water in the ink used in the present invention is preferably between 50 and 90% by weight.

The dye used in the present invention is a direct dye,
Examples include acid dyes, basic dyes, reactive dyes, disperse dyes, vat dyes, and the like. The content of these dyes is determined depending on the type of liquid medium component, the characteristics required for the ink, the ejection amount of the recording head, and the like, but generally 0.5 to the total weight of the ink. The range is 15% by weight, preferably 1 to 7% by weight. It was also found that the addition of thiodiglycol or urea (or its derivative) to the ink drastically improves the ejection characteristics and the effect of preventing clogging (fixation). It is considered that the addition of these improves the solubility of the dye in the ink. The content of thiodiglycol or urea (or its derivative) is preferably 1
It is up to 30% by weight and can be added if necessary.

The main components of the ink of the present invention are as described above, but in addition to these, viscosity adjusting agents such as polyvinyl alcohol, celluloses, water-soluble resins; diethanolamine,
A pH adjusting agent such as triethanolamine and a buffer solution, an antifungal agent and the like can be added as necessary within a range not hindering the object of the present invention.

Further, in order to prepare the ink used in the ink jet recording apparatus of the type which charges the ink, a specific resistance adjusting agent such as an inorganic salt such as lithium chloride, ammonium chloride or sodium chloride is added.

In the present embodiment, a single color ink has been described as an example for convenience of description, but the present invention is not particularly limited to this, and a color including a plurality of different dark and light inks such as cyan, magenta, yellow and black, respectively. It can also be applied to recording devices. Further, the dye density of the ink is not limited to two kinds of light and shade, and may be three or more kinds. For example, by using light density ink, medium density ink, high density ink, etc., the light density ink and the middle density ink are ink compositions of ink composition in which dots spread easily, and the high density ink is recorded with a composition that emphasizes character quality. You may do it.

(Second Embodiment) FIG. 12 is a perspective view showing a main structure of an ink jet recording apparatus according to a second embodiment of the present invention, which basically operates in the same manner as in the first embodiment. Is.

FIG. 13 is a schematic perspective view of the ink discharge port array of the recording head 12 as viewed from the recording material side.

This has one ejection head array 2A for ejecting dark color ink and ejection port row 2B for ejecting light color ink on one recording head 12.

When recording is performed using dark and light inks, the problem of the deviation of the landing positions of the dark ink dots and the light ink dots is very important, and the density may change due to the deviation of the dots. By disposing a plurality of ejection port arrays for ejecting inks of different densities in a single recording head as in the present embodiment, there is no misregistration in the vertical and horizontal directions. It has the feature that there is no worry of out of order.

FIG. 14 is an explanatory view of the constitution of the ink jet recording head used in this embodiment.

One end of the wiring board 200 is mutually connected to the wiring portion of the heater board 100, and the wiring board 2 is further connected.
A plurality of pads corresponding to the respective electric / thermal energy converters for receiving an electric signal from the present device are provided at the other end of 00. As a result, the electric signal from the main body device is supplied to each electric / thermal energy converter.

The metal support 300, which supports the back surface of the wiring board 200 on a flat surface, serves as the bottom plate of the ink jet unit. The presser spring 500 is a claw that is hooked by using a portion formed by bending a groove in the vicinity of the ink discharge port of the groove top 1300 in a substantially U-shaped cross section and an escape hole provided in the base plate to elastically exert a pressing force on the line. The base plate has a pair of rear legs that receive the force acting on the spring.

By this spring force, the wiring board 200 and the groove 1
It is in pressure contact with 300.

The wiring board 200 is attached to the support by sticking with an adhesive or the like.

A filter 700 is provided at the end of the ink supply pipe 2200.

The ink supply member 600 is formed by molding, and the groove top 1300 is also the orifice plate portion 1301.
And a flow path 1500 leading to each ink supply port is integrally formed. To fix the ink supply member 600 to the support 300, two pins (not shown) on the back surface side of the ink supply member 600 are projected through the holes 1901 and 1902 of the support 300, respectively, and heat-sealed. Made easier by.

At this time, the gap between the orifice plate portion 1301 and the ink supply member 600 is formed uniformly. The sealant is injected from the upper sealant injection port of the ink supply member 600 to seal the wire bonding, and at the same time, the orifice plate portion 1301 and the ink supply member 60.
The gap between the orifice plate portion 1301 and the front end of the support base 300 is completely sealed by passing through the groove 310 provided in the support base 300.

FIG. 15 is a perspective view of the groove head 1300 of the recording head used in this embodiment as seen from the heater board 100 side. A plurality of liquid chambers are provided, and each liquid chamber has a wall 10
It is divided by. Each liquid chamber is provided with supply ports 20a and 20b for supplying ink.

Grooves 30 are provided on the pressure-contacting surface of the wall 10 partitioning each liquid chamber with the heater board 100. This groove is
It communicates with the outer peripheral portion of Mizoten 1300. After the groove mound 1300 is pressed against and closely adhered to the heater board, the outer peripheral portion is sealed with the sealant as described above. At this time, the sealant penetrates along the groove to fill the gap between the groove and the heater board. In this way, the liquid chamber can be completely separated by the technical process conventionally used in the head. The structure of this groove differs depending on the physical properties of the sealant, and it is necessary to make the shape corresponding to each.

By thus dividing the liquid chamber into a plurality of chambers, different inks can be supplied to the respective ink ejection ports.

FIG. 16 shows a state in which the recording head and the ink tank of the embodiment are mounted on the carriage. The ink tank IT is divided into two rooms, an upper room and a lower room, filled with a light ink and a lower room with a dark ink. Then, on the carriage 23, the recording head 12
And the ink tank IT are pressure-bonded to each other and the ink tank IT
Thus, each dark and light ink is supplied to the recording head 12.

The method of distributing the light ink data and the dark ink data to the data input using the density distribution table is the same as that of the first embodiment, and C, which is input based on the density distribution table, The M, Y, K data are distributed into light ink data (C ', M', Y ', K') and dark ink data (C ", M", Y ", K"),
Each is binarized by the binarization circuit and turned on / on the print head.
It is output as off data (1 bit signal).

An example of the ink composition used in the second embodiment is shown below. Composition (ink composition with small dot spread) Dye 0.5 to 5 wt% Diethylene glycol 5 wt% Thiodiglycol 5 wt% Ethyl alcohol 3 wt% Pure water balance Composition (ink composition with large dot spread) Dye 0.5 to 5 wt % Glycerin 5 wt% Thiodiglycol 5 wt% Ethylene oxide-propylene oxide copolymer 3 wt% Urea 5 wt% Pure water balance

In this embodiment, a composition in which dots do not spread easily is used as the dark ink composition, a composition in which dots spread easily is used as the light ink composition, and the dark ink nozzle row is arranged at the bottom and the light ink nozzle row is arranged at the top. That is, in the halftone density area in which the light dots and the dark dots are printed, the dark ink dots in which the dots are hard to spread are printed and then the light ink dots in which the dots are easy to spread are printed. As described in the first embodiment, the ink having a composition in which dots do not spread easily has a low fixing property because of poor penetrability. In the vicinity of the dark / light ink switching portion where the graininess is easily noticeable, the number of dots of the light ink dots is larger than that of the dark ink dots. Therefore, since the dark ink dots are struck around the unfixed dark ink dots, the dark ink dots and the light ink dots easily mix with each other, and the dark ink dots spread and the graininess is eased.

According to the present embodiment, it is possible to increase the number of recording heads by combining the ejection port array for ejecting dark ink and the ejection port array for ejecting light ink into one recording head.
Further, the device can be made smaller.

Further, in this embodiment, the light ink and the dark ink are not overlapped in the same carriage scan, the dark ink is ejected in the first main scan, the paper is then fed, and the light ink is lightened in the next carriage main scan. Ink is designed to be stacked. According to the present embodiment, since it is possible to set the dark and light ink ejection intervals in this way, it is also possible to take a time for the dark ink with slow penetrability to penetrate even if it is ejected first. The bleeding can be adjusted as compared with the embodiment. Further, even in the case of the bidirectional recording method, it is possible to control the bleeding method in the forward and backward passes of the carriage main scanning in substantially the same manner.

In the present embodiment, for the sake of convenience of description, a single color ink has been described as an example. However, the present invention is not limited to this, and a plurality of different dark and light inks such as cyan, magenta, yellow and black are provided. It can also be applied to color recording devices.

Further, the dye concentration of the ink is not limited to two kinds of light and shade, but may be three or more kinds. For example, by using light density ink, medium density ink, high density ink, etc., the light density ink and the middle density ink should be inks having a composition in which dots easily spread, and the high density ink should be a composition that emphasizes character quality before printing. You can

(Third Embodiment) FIG. 17 is a perspective view showing the essential structure of a color ink jet recording apparatus as a recording apparatus according to the second embodiment of the present invention. The same operation is performed.

FIG. 18 is a schematic perspective view of the ink discharge port array of the recording head as viewed from the recording material side.

This is a recording head 12C for ejecting C (cyan) color ink, a recording head 12M for ejecting M (magenta) color ink, and a recording head 12Y, K (black) color ink for ejecting Y (yellow) color ink. 1 shows a color ink jet recording apparatus having four color recording heads, which are recording heads 12K for ejecting ink. Each recording head includes an ejection port array 2A for ejecting dark color ink and an ejection port array 2B for ejecting light color ink. And is installed on the carriage 23 at a predetermined distance.

When recording is performed using dark and light inks, the deviation of the landing positions of the dark ink dots and the light ink dots is also very important, and the density may change due to the deviation of the dots. Also in this embodiment, since a plurality of ejection port arrays for ejecting inks of different densities of light and shade are divided and arranged in one recording head, there is no misregistration in the vertical and horizontal directions, so that the density gradation due to the landing position is eliminated. It has the feature that there is no worry of slippage.

FIG. 19 shows the structure of a four-head integrated ink jet cartridge (IJC) in which recording heads for four colors of C, M, Y and K are integrally assembled in a frame 3000. The four recording heads are mounted in the frame 3000 at predetermined intervals, and the resists in the nozzle array direction are also fixed in an adjusted state. Reference numeral 3100 is a frame cover, and 3200 is a connector for connecting pads provided on the wiring board 200 of the four recording heads and electrical signals from the main body apparatus.

FIG. 20 shows how the four-head integrated ink jet cartridge is mounted on the carriage. The ink tank (IT) is divided into two rooms, an upper room and a lower room, filled with light ink and lower room with dark ink. Then, on the carriage 23, the ink jet cartridge 3000 and the four C, M, Y and K
Each ink tank (IT) is pressure-bonded to each other, and each ink is supplied from the ink tank to the recording head.

The method of distributing the light ink data and the dark ink data to the data input using the density distribution table is the same as that of the first embodiment, and C input based on the density distribution table, The M, Y and K data are distributed to light ink data (C ′, M ′, Y ′ and K ′) and dark ink data (C ″, M ″, Y ″ and K ″),
Each is binarized by the binarization circuit and turned on / on the print head.
It is output as off data (1 bit signal).

In the case of color recording, bleeding at different color boundary portions when different colors are adjacent to each other is also important. The ink of the composition (composition) in which the dot spreads easily as described in the first or second embodiment has excellent penetrability into paper, and is excellent in that unreasonable bleeding does not occur at the boundary portion between different colors. It has a property. On the other hand, since the ink composition (composition) in which dots do not spread easily has poor penetrability into paper, bleeding occurs at the boundary portion of different colors on the paper surface, causing image deterioration.

Therefore, in the present embodiment, in order to improve the quality of characters and fine lines, only the dark dark ink of black has an ink composition in which the dots are difficult to spread, and in order to improve the quality of halftone color recording such as a natural image. The black light ink and each of the cyan, magenta, and yellow dark and light inks have an ink composition in which dots easily spread and bleeding does not occur at the boundary portion of different colors.

The present invention is particularly effective in an ink jet recording head and a recording apparatus for recording by forming flying droplets by utilizing thermal energy among the ink jet recording systems.

With regard to its typical structure and principle, see, for example, US Pat. Nos. 4,723,129 and 4740.
What is done using the basic principles disclosed in 796 is preferred. This method can be applied to both the so-called on-demand type and continuous type, but especially in the case of the on-demand type, liquid (ink)
By applying at least one drive signal to the electrothermal converter arranged corresponding to the sheet or liquid path in which is stored, which corresponds to the recorded information and causes a rapid temperature rise exceeding nucleate boiling. , It is effective because it generates heat energy in the electrothermal converter and causes film boiling on the heat-acting surface of the recording head, resulting in the formation of bubbles in the liquid (ink) corresponding to this drive signal on a one-to-one basis. Is. The liquid (ink) is ejected through the ejection openings by the growth and contraction of the bubbles to form at least one droplet. It is more preferable to make this drive signal into a pulse shape because bubbles can be immediately and appropriately grown and contracted, so that liquid (ink) ejection with excellent responsiveness can be achieved.

As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, further excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the discharge port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned respective specifications, A configuration using US Pat. No. 4,558,333 or US Pat. No. 4,459,600, which discloses a configuration in which the heat acting portion is arranged in the bending region, may be used.

In addition, JP-A-59-123670 discloses a structure in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and a pressure wave of thermal energy is absorbed. It is also possible to adopt a configuration based on Japanese Patent Laid-Open No. 59-138461, which discloses a configuration in which the opening corresponds to the ejection portion.

Further, as a full line type recording head having a length corresponding to the maximum recording medium width that can be recorded by the recording apparatus, the length can be increased by combining a plurality of recording heads as disclosed in the above-mentioned specification. Either of the structure satisfying the requirement or the structure as one recording head integrally formed may be used.

In addition, by being attached to the apparatus main body, it can be electrically connected to the apparatus main body and can be supplied with ink from the apparatus main body by a replaceable chip type recording head or the recording head itself. Alternatively, a cartridge type recording head provided with an ink tank may be used.

Further, it is preferable to add recovery means for the recording head, preliminary auxiliary means, etc., which are provided as a configuration of the recording apparatus of the present invention, because the effects of the present invention can be further stabilized. If you list these specifically,
Capping means, cleaning means, pressurizing or sucking means for the recording head, preheating means using an electrothermal converter or another heating element or a combination thereof, and a preliminary ejection mode for performing ejection other than recording It is also effective to perform stable recording.

In the embodiments of the present invention described above, the ink is described as a liquid, but it is an ink that solidifies at room temperature or lower and that softens at room temperature or is a liquid, or the above-mentioned. In the inkjet method, the temperature of the ink itself is generally adjusted within a range of 30 ° C. or higher and 70 ° C. or lower to control the temperature of the ink so that the viscosity of the ink is within a stable ejection range. It may be in a liquid form.

In addition, the temperature rise due to the thermal energy is positively prevented by using it as the energy for changing the state of the ink from the solid state to the liquid state, or the ink is solidified in a standing state for the purpose of preventing evaporation of the ink. In some cases, such as ink that is liquefied by applying heat energy according to a recording signal and ejected as a liquid ink, or one that has already started to solidify when it reaches a recording medium. The use of an ink having a property of being liquefied only by heat energy is also applicable to the present invention. In such a case, the ink is disclosed in JP-A-54-5684.
No. 7 or JP-A-60-71260, a mode in which the porous sheet is opposed to the electrothermal converter in the state of being held as a liquid or solid in the recess or through hole of the porous sheet. May be In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as a form of the recording apparatus according to the present invention, the recording apparatus according to the present invention is integrally or separately provided as an image output terminal of the information processing equipment such as the word processor or the computer, and is combined with a reader or the like. It may be in the form of a copying machine or a facsimile machine having a transmission / reception function.

FIG. 21 is a block diagram showing a schematic configuration when the recording apparatus of the present invention is applied to an information processing apparatus having a function as a word processor, a personal computer, a facsimile apparatus, a copying apparatus, an electronic typewriter or the like. In the figure, 201 is a control unit for controlling the entire apparatus,
A CPU such as a microprocessor and various I / O ports are provided, and control signals and data signals are output to each unit and control signals and data signals are input from each unit for control. A display unit 202 displays various menus, document information, image data read by the image reader 207, and the like on this display screen. A transparent pressure-sensitive touch panel 203 is provided on the display unit 202. By pressing the surface of the touch panel with a finger or the like, it is possible to perform item input, coordinate position input, and the like on the display unit 202.

Reference numeral 204 is an FM (Frequency Mo)
In the sound source unit, music information created by a music editor or the like is stored as digital data in the memory unit 210 or the external storage device 212, and is read from the memory or the like to perform FM modulation. FM sound source section 2
The electric signal from 04 is converted into an audible sound by the speaker unit 205. The printer unit 206 includes a word processor, a personal computer, a facsimile machine, a copying machine,
The recording apparatus according to the present invention is applied as an output terminal such as an electronic typewriter.

An image reader unit 207 photoelectrically reads original data and inputs it, which is provided in the middle of the original feeding path and reads various originals in addition to facsimile originals and copy originals. 208 is an image reader unit or 2
A facsimile transmission / reception unit that transmits the original data read in 07 by facsimile and receives and decodes the transmitted facsimile signal, and has an interface function with the outside. A telephone unit 209 has various telephone functions such as a normal telephone function and an answering machine function. A memory unit 210 includes a ROM for storing a system program, a manager program, other application programs, etc., a character font, a dictionary, etc., an application program loaded from an external storage device 212, character information, and a video RAM.

Reference numeral 211 denotes a keyboard unit for inputting document information and various commands. An external storage device 212 has a floppy disk, a hard disk, or the like as a storage medium.
The external storage device 212 stores character information, music or voice information, user application programs, and the like.

FIG. 22 is an external view of the information processing apparatus shown in FIG. In the figure, 301 is a flat panel display using liquid crystal or the like, which displays various menus, graphic information, character information, and the like. A touch panel is installed on the display 301, and by pressing the surface of the touch panel with a finger or the like, coordinate input and item designation input can be performed. 302 is a handset used when the device functions as a telephone.

The keyboard 303 is detachably connected to the main body via a cord, and various character information and various data can be input. Also, this keyboard 303
Is provided with various function keys 304 and the like. Reference numeral 305 is a floppy disk insertion port.

Reference numeral 307 denotes a paper placing portion on which an original read by the image reader 207 is placed, and the read original is discharged from the rear portion of the apparatus. When receiving a facsimile, the data is recorded by the printer 307.

The display 301 may be a CRT, but a flat panel such as a liquid crystal display using ferroelectric liquid crystal is desirable. This is because in addition to being small and thin, it is possible to reduce the weight. When the information processing device functions as a personal computer or a word processor,
In FIG. 21, various information input from the keyboard unit 211 is processed by the control unit 201 according to a predetermined program, and output as an image to the printer unit 206. When functioning as a receiver of a facsimile apparatus, the facsimile information input from the facsimile transmission / reception unit 208 via the communication line is received by the control unit 201 according to a predetermined program, and output to the printer unit 206 as a received image.

In the case of functioning as a copying machine, a document is read by the image reader unit 207, and the read document data is transferred to the printer unit 206 via the control unit 201.
Is output as a copy image to. In addition, when functioning as a transmitter of a facsimile apparatus, the image reader unit 207
The document data read by is subjected to transmission processing by the control unit 201 according to a predetermined program, and then transmitted to the communication line via the facsimile transmission / reception unit 208.
Note that the information processing apparatus described above may be an integrated type in which a printer is built in the main body as shown in FIG. 23, and in this case, it becomes possible to further enhance portability. In the figure, the parts having the same functions as those in FIG. 22 are designated by the corresponding reference numerals.

By applying the recording apparatus of the present invention to the multifunctional information processing apparatus described above, a high-quality recorded image can be obtained, so that the function of the information processing apparatus can be further improved. Become.

[0110]

As described above, according to the present invention, in an ink jet recording apparatus for forming an image by ejecting a plurality of inks having different dye densities, a recording medium of at least two kinds of inks having different dye densities. By changing the penetrability above, the printing quality of black characters and fine lines is good, and the gradation of halftones is smooth, making it difficult for the proceedings to occur and changing the graininess of the recorded image. It is also possible to record a natural image in which a change in color tone is unlikely to occur at the ink switching portion.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of an inkjet recording apparatus to which the present invention is applied.

FIG. 2 is a schematic partial perspective view in the vicinity of a discharge port of a recording head.

FIG. 3 is a partial perspective view schematically showing the structure of an ink ejection portion of the recording head.

FIG. 4 is a block diagram showing the configuration of an inkjet recording apparatus.

FIG. 5 is a block diagram of an image signal processing unit.

FIG. 6 is an example of a conversion graph of a gradation distribution table.

FIG. 7 is a state diagram of dots with an ink composition in which the dots do not spread easily.

FIG. 8 is a state diagram of dots with an ink composition in which dots are easily spread.

FIG. 9: Character quality with ink composition in which dots do not spread easily.

FIG. 10: Character quality with ink composition in which dots easily spread.

FIG. 11 is a state diagram of dots when a dot having an ink composition that easily spreads and a dot having an ink composition that does not spread easily come into contact with each other.

FIG. 12 is a schematic explanatory diagram of an inkjet recording apparatus to which a second embodiment is applied.

FIG. 13 is a schematic partial perspective view of the vicinity of the ejection port of the recording head according to the second embodiment.

FIG. 14 is an explanatory diagram of a configuration of a recording head.

FIG. 15 is a perspective view illustrating the structure of a groove.

FIG. 16 is an explanatory diagram of mounting a recording head and an ink tank on a carriage.

FIG. 17 is a schematic explanatory diagram of an ink jet recording apparatus to which a third embodiment is applied.

FIG. 18 is a schematic partial perspective view of the vicinity of the ejection port of the recording head according to the third embodiment.

FIG. 19 is an explanatory diagram of a configuration of a 4-head integrated inkjet cartridge.

FIG. 20 is an explanatory diagram of mounting an inkjet cartridge and an ink tank on a carriage.

FIG. 21 is a block diagram showing a schematic configuration when the recording apparatus of the present invention is applied to an information processing apparatus.

FIG. 22 is an external view of the information processing device.

FIG. 23 is an external view showing another example of the information processing apparatus.

[Explanation of symbols]

12, 12A, 12B, 12K, 12C, 12M, 12
Y recording head 21 paper ejection roller 22 guide shaft 23 carriage 24 drive belt 25 carriage motor 26 cap portion

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B41M 5/00 A 8808-2H

Claims (11)

[Claims] 1. An inkjet recording apparatus for forming an image by ejecting ink onto a recording medium using a plurality of ink ejecting means capable of ejecting a plurality of inks having different densities, wherein at least two of the ink ejecting means are provided. Is an ink jet recording apparatus, which ejects inks having different densities and different penetrability on a recording medium. 2. The ink jet recording apparatus according to claim 1, wherein the inks having different densities and different penetrating properties on the recording medium are inks of similar colors. 3. The ink ejecting means is means for ejecting ink by utilizing thermal energy, and is provided with a thermal energy converter for generating thermal energy applied to the ink. Inkjet recording device. 4. The ink ejecting means causes the ink to undergo a state change by the thermal energy applied by the thermal energy converter, and ejects the ink from an ejection port based on the state change. The inkjet recording device described. 5. An image forming apparatus comprising the ink jet recording apparatus according to claim 1 and a document image reading unit. 6. An image forming apparatus comprising the inkjet recording apparatus according to claim 1 and a transmission and / or reception unit for image information. 7. The image forming apparatus according to claim 6, further comprising a document image reading unit. 8. An image forming apparatus comprising the inkjet recording apparatus according to claim 1 and a recording signal input unit. 9. The image forming apparatus according to claim 8, wherein the recording signal input means is a keyboard. 10. An ink jet recording method for forming an image by adhering a plurality of inks having different densities to a recording medium, wherein an image is formed by adhering inks having different densities and different penetrability on the recording medium to the recording medium. An ink jet recording method, which comprises forming. 11. A recorded matter, wherein an image is formed on a recording medium using a plurality of inks having different densities and different penetrability on the recording medium.