JP4700272B2 - Inkjet recording method and recording apparatus - Google Patents

Description

  The present invention relates to an ink jet recording method and a recording apparatus for forming an image on a recording medium using ink.

2. Description of the Related Art A so-called serial printer type ink jet recording apparatus is widely used which includes a recording element array in which a plurality of recording elements are arranged in an ink jet head and performs recording by scanning the ink jet head on a recording medium during recording.
An ink jet recording apparatus performs recording by ejecting ink droplets from a discharge port onto a recording medium. As a method for ejecting ink droplets, an electrothermal transducer as a thermal energy generating element is provided in an ink path near the ejection port, and this electrothermal transducer is driven to generate bubbles by film boiling in the ink. Ink droplets are ejected using a bubble jet (registered trademark) system that discharges ink droplets with a generated pressure, or a piezoelectric element such as a piezo element is used as an ejection energy generating element, and ink is generated using the pressure generated when the piezoelectric element is deformed. A method of discharging is used.
When recording is performed using an inkjet head having a plurality of recording elements such as the ejection openings described above, the quality of the recorded image largely depends on the performance of the inkjet head alone. For example, due to slight errors that occur in the inkjet head manufacturing process, such as errors in the shape of each discharge port and variations in the formation position of the electrothermal transducer, the discharge amount, discharge direction, etc. may differ slightly from one discharge port to another. is there. As a result, errors such as minute deviations in the landing positions of the ink droplets ejected from the respective ejection openings or different sizes of the dots formed occur, and this error causes a streak in the image. Density unevenness such as unevenness is generated and image quality is deteriorated.

Therefore, in order to prevent such density unevenness that degrades the image quality, for example, a method of scanning the same portion of the recording medium a plurality of times to complete an image, a so-called multipass recording method, recording for each recording element is performed. Some have been proposed to mitigate variations in characteristics.
That is, in the normal recording method, when the ink jet head prints for one scan, the paper is fed by the width of the ink jet head and the next area is recorded. For this reason, the ink jet head does not scan the same area of the recording medium a plurality of times. Therefore, for example, when there is a variation in recording characteristics for each recording element, the variation is directly displayed as density unevenness in an image.
On the other hand, in the multi-pass recording method, the inkjet head is divided into units of several recording elements, paper feeding is performed corresponding to the divided one block, and the inkjet head scans the same area of the recording medium a plurality of times, Each time this scanning is performed, recording is performed with recording elements of different blocks. For example, as shown in FIG. 8, when the 16 recording elements of the inkjet head are divided into 4 blocks, the same region is scanned 4 times to complete the image. Therefore, even if there is a variation in recording characteristics for each recording element, since the recording elements for recording each area are dispersed, the influence of the difference in recording characteristics on each area is mitigated, and the density unevenness becomes inconspicuous. .

As described above, according to the multi-pass printing method, the density unevenness caused by the variation in the printing characteristics between printing elements in the inkjet head can be reduced in units of the scanning area of the inkjet head.
However, there may be a difference in the density and color of the image recorded between the scanning areas of the inkjet head. As a result, the entire recording image has striped unevenness (hereinafter referred to as “banding”) with the period of the width of the scanning area. Unevenness ”) may occur and the recording quality may be lowered.
One of the main causes of the difference in density between scanning areas is the amount of movement mainly in the sub-scanning direction (paper feed direction) in each scan when a plurality of scans are performed on each area to complete recording. Variation, that is, variation due to paper feeding accuracy. When the variation in the paper feed amount is large, a portion where the dot pitch in the sub-scanning direction is narrower than a desired pitch and a wide portion are generated. In a portion where the dot pitch is narrow, dots are overlapped more than necessary and the density is perceived to be high, and in a wide portion, the density is low and white stripes may occur.

As a countermeasure against the above-mentioned banding unevenness, for example, in the multi-pass recording method, by increasing the number of divisions, the formed bind pitch (density unevenness cycle) is shortened, and this striped unevenness is detected by human vision. In this way, a method for making banding unevenness inconspicuous has been proposed.
However, this method shortens the paper feed width at one time and increases the number of scans, so that the time required for the entire recording becomes longer, which is a detrimental effect of increasing the recording speed.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a recording apparatus and an ink jet recording method for forming an image with excellent print quality and invisible banding unevenness even with a relatively small number of scans.

As a result of intensive studies on the above problems, the present inventors have found that if the resolution (printing density) is sufficiently high, the dot shape is close to a circle, and printing is performed with dots of a size larger than previously thought. The present inventors have found that the printing quality is excellent, the banding unevenness can be made inconspicuous, and the visual resolution is not lowered.
That is, the above-mentioned problem is (1) “Inkjet recording method for forming an image by ejecting ink from an inkjet head onto a recording medium, wherein the ink comprises a colorant, a wetting agent, a carbon number. 8 to 11 polyol or glycol ether, an anionic or nonionic surfactant, and a water-soluble organic solvent, the content of the colorant is 8% by weight or more, and the content of the wetting agent is 10 to 50% by weight. , A water-based ink having a viscosity at 25 ° C. of 8 mPa · sec or more , and the colorant is a pigment or a polymer emulsion in which a polymer fine particle contains a water-insoluble or hardly soluble colorant, and the wetting agent Is glycerin or glycerin and 1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol 1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, trimethylolethane, 1,4-butanediol, and 2-methyl-2,4-pentanediol were mixed. A high-viscosity wetting agent, wherein the recording medium is a recording medium provided with an ink-receiving layer on a support, and the resolution of a color image formed on the recording medium is 600 dpi to 1200 dpi, The dot diameter Dd (μm) after the ink droplet applied on the recording medium is fixed is

（但し、Ｄｐ（μｍ）は隣接する画素の中心間距離で、解像度（印写密度）をＲ（ｄｐｉ）とすれば、Ｄｐ＝２．５４×１０^４／Ｒ）であり、かつ、ドットの形状係数が１．１５以上１．５０以下であることを特徴とするインクジェット記録方法」、（２）「前記インクは、少なくともイエロー、シアン及びマゼンタの３色を含む複数色のインクであることを特徴とする前記第（１）項に記載のカラーインクジェット記録方法」、（３）「前記インクジェットヘッドは、インクを吐出するための熱エネルギーを発生する熱エネルギー発生体を備えることを特徴とする前記第（１）項または第（２）項に記載のカラーインクジェット記録方法」、（４）「前記インクジェットヘッドは、インクに力学的エネルギーを作用させてインク吐出を行なうことを特徴とする前記第（１）項または第（２）項に記載のインクジェット記録方法」、（５）「前記記録媒体がＯＨＰ用シートであることを特徴とする前記第（１）項乃至第（４）項の何れかに記載のインクジェット記録方法」により達成される。
また、上記課題は、本発明の（６）「インクを吐出するための複数の吐出部を有するインクジェットヘッドを記録媒体に対して相対的に走査させながら記録媒体にインクを吐出し、１画素に単色ドットを付与することで画像データに応じた画像を前記記録媒体上に形成するインクジェット記録装置であって、前記インクは、着色剤、湿潤剤、炭素数８〜１１のポリオールまたはグリコールエーテル、アニオンまたはノニオン系界面活性剤、及び、水溶性有機溶剤を含み、前記着色剤の含有量が８重量％以上、前記湿潤剤の含有量が１０〜５０重量％、２５℃に於ける粘度が８ｍＰａ・ｓｅｃ以上である水性インクであり、前記着色剤は、顔料、またはポリマー微粒子に水不溶性または難溶性の色材を含有させたポリマーエマルジョンであり、前記湿潤剤は、グリセリンまたは、グリセリンと１，３−ブタンジオール、トリエチレングリコール、１，６−ヘキサンジオール、プロピレングリコール、１，５−ペンタンジオール、ジエチレングリコール、ジプロピレングリコール、トリメチロールプロパン、トリメチロールエタン、1，4−ブタンジオール、２−メチル−２，４−ペンタンジオールから選ばれた少なくとも１種類以上を混合した高粘度の湿潤剤であり、前記記録媒体は支持体上にインクの受容層が設けられた記録媒体であり、前記記録媒体上に形成される画像の解像度は６００ｄｐｉ以上１２００ｄｐｉ以下であり、前記記録媒体上に付与されたインクのドット（滴）が定着した後のドット径Ｄｄ（μｍ）が、

(However, Dp (μm) is the distance between the centers of adjacent pixels, and if the resolution (printing density) is R (dpi), then Dp = 2.54 × 10 ⁴ / R) and the dot Inkjet recording method characterized in that shape factor is 1.15 or more and 1.50 or less ", (2)" The ink is a plurality of colors including at least three colors of yellow, cyan and magenta. " The color ink jet recording method according to item (1), which is characterized in that, (3) “The ink jet head includes a thermal energy generator that generates thermal energy for ejecting ink. paragraph (1) or the (2) color ink jet recording method according to claim "(4)" the ink jet head, by applying mechanical energy to the ink line of ink ejection Wherein characterized Ukoto paragraph (1) or the (2) The ink jet recording method according to claim "(5)" the first (1), characterized in that the said recording medium is an OHP sheet Thru | or the inkjet recording method in any one of ( 4 ) term.
In addition, the above-described problem is solved by ( 6 ) “injecting ink onto a recording medium while scanning an inkjet head having a plurality of ejection portions for ejecting ink relative to the recording medium. An ink jet recording apparatus for forming an image according to image data on a recording medium by applying a single color dot, wherein the ink includes a colorant, a wetting agent, a polyol or glycol ether having 8 to 11 carbon atoms, an anion Or a nonionic surfactant and a water-soluble organic solvent, the colorant content is 8% by weight or more, the wetting agent content is 10 to 50% by weight , and the viscosity at 25 ° C. is 8 mPa · a water-based ink is sec or more, the colorant is located in the pigment, or the polymer fine particles are contained a water-insoluble colorant or sparingly soluble polymer emulsion The wetting agent is glycerin or glycerin and 1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, trimethylol. It is a high viscosity wetting agent in which at least one selected from ethane, 1,4-butanediol, and 2-methyl-2,4-pentanediol is mixed, and the recording medium is an ink receiving layer on a support. The resolution of an image formed on the recording medium is 600 dpi or more and 1200 dpi or less, and the dot diameter Dd after the ink dots (droplets) applied on the recording medium are fixed (Μm)

（但し、Ｄｐ（μｍ）は隣接する画素の中心間距離で、解像度（印写密度）をＲ（ｄｐｉ）とすれば、Ｄｐ＝２．５４×１０^４／Ｒ）であり、かつ、ドットの形状係数が１．１５以上１．５０以下となるように、前記画像データに基づく記録を前記インクジェットヘッドに行わせる駆動手段を備えることを特徴とするインクジェット記録装置」、（７）「前記インクジェットヘッドは、インクを吐出するための熱エネルギーを発生する熱エネルギー発生体を備えることを特徴とする前記第（６）項に記載のインクジェット記録装置」、（８）「前記インクジェットヘッドは、インクに力学的エネルギーを作用させてインク吐出を行なうことを特徴とする前記第（６）項または第（７）項に記載のインクジェット記録装置」、（９）「前記記録媒体を搬送するための搬送部に、記録媒体を静電吸着して搬送するための搬送ベルトを備えたことを特徴とする前記第（６）項乃至第（８）項に記載のインクジェット記録装置」により達成される。

(However, Dp (μm) is the distance between the centers of adjacent pixels, and if the resolution (printing density) is R (dpi), then Dp = 2.54 × 10 ⁴ / R) and the dot Inkjet recording apparatus comprising drive means for causing the inkjet head to perform recording based on the image data so that the shape factor is 1.15 or more and 1.50 or less ", ( 7 )" The inkjet head the ink jet recording apparatus according to the first (6), characterized in further comprising a thermal energy generator for generating thermal energy for discharging ink "(8)" the ink-jet head, mechanics ink specifically the energy to act on and performing ink ejection with the (6) the ink-jet recording apparatus according to claim or a (7) section "(9)" The conveyance unit for conveying the serial recording medium, ink jet according to the first (6) section to the (8) section, characterized in that a conveying belt for conveying the recording medium by electrostatic adsorption Achieved by a "recording device".

  As is clear from the following detailed and specific description, according to the present invention, the dot shape is close to a circle, and the dot diameter with respect to the resolution (printing density) is set in an appropriate range, so that it is relatively small. Even with the number of scans, it is possible to form an image with excellent print quality and invisible banding unevenness.

Embodiments to which the ink jet recording method and recording apparatus of the present invention are applied will be described below.
FIG. 7 is a perspective view schematically showing a configuration of a serial type ink jet printer which is an embodiment of the image forming method and the image forming apparatus according to the present invention. The ink jet printer (711) is provided in a state in which a paper feeding unit (710) (paper feeding device) is fitted from the back of the housing (only the outer frame is shown to show the inside) obliquely forward and downward. . The recording medium (7P) placed on the paper feeding unit (710) is conveyed in the forward direction (sub-scanning direction) as indicated by an arrow (7a).

  The print head (712) is attached to the steel strip (715) that reciprocates as indicated by an arrow (7b) by the print head drive mechanism (717) and crosses the conveyed paper (7P) (crossing direction). ) Is provided so as to reciprocate along a rail (713) installed on the rail. The print head (712) prints by ejecting ink onto the recording medium (7P) transported below and temporarily stopped along the rail (713) while reciprocating in the direction indicated by the arrow (7b). The recording medium (7P) is conveyed by a predetermined distance for the next scanning after the printing of the printing head (712) for one scanning is completed.

Using an inkjet head in which 384 nozzles are arranged at an interval of 300 dpi, this head is divided into 8 units in units of 48 nozzles, and paper is fed corresponding to the divided one block, and the same area of the recording medium is inkjet head Will be described in the case of a multi-pass recording method in which the image is scanned eight times and recorded at a resolution of 600 dpi.
Since the resolution is 600 dpi, the center-to-center distance Dp (μm) between adjacent pixels is about 42.3 μm, and therefore the ideal dot diameter (in the case of the recording apparatus) assumed that there is no variation in dot size and position is about 59.8 μm. In the recording method of the present invention, by recording so that the dot diameter Dd is in the range of about 72 μm to about 96 μm, it is possible to form an image with no noticeable banding unevenness.
At this time, if the dot shape factor is 1.50 or less, a recorded image with high sharpness without blurring or blurring is obtained in the peripheral portion of an image such as a character, and the solid image portion has a high quality with little roughness. The recorded image is obtained.

Method of measuring dot diameter Dd The dot diameter Dd was determined as follows. After taking the dots on the recording paper with a CCD camera and binarizing, find the area of the dots from the number of pixels that form the dots, convert it to a perfect circle, and convert the true circle diameter (equivalent circle diameter) to dot The diameter was Dd. Specifically, a dot analyzer DA-5000S, which is an image processing / analysis system manufactured by Oji Scientific Instruments Co., Ltd., was used as a measuring device. The number of dots to be measured is preferably 100 or more, and the average value thereof is adopted.

Shape factor The dot shape factor was determined from the following equation using the above-described dot analyzer DA-5000S in the same manner as the dot diameter.

真円の形状係数は１で、１より大きい程複雑な形状であることを示す。

The shape factor of a perfect circle is 1, and a larger shape than 1 indicates a more complicated shape.

  The dot diameter Dd referred to in the present invention refers to the diameter of a dot used in the highest image density portion of each color. For example, in the case of a multi-size dot method that uses ink droplets of a plurality of sizes such as large, medium, and small. Refers to the diameter of the dot formed from the largest ink drop used in that print mode.

の値が１．２０よりも小さければ、「バンディングむら」が目立ちやすくなり、一方、１．６０以上であると、文字等の画像部の滲みや太りが発生しやすくなり、視認上の解像度も低下する。 When the dot diameter after the ink droplet is fixed is Dd (μm) and the distance between the centers of adjacent pixels is Dp (μm) (provided that the resolution (printing density) is R (dpi)), Dp = 2.54 × 10 ⁴ / R)

If the value is smaller than 1.20, “banding unevenness” is more noticeable. On the other hand, if it is 1.60 or more, blurring and fatness of image portions such as characters are likely to occur, and the visual resolution is also high. descend.

の値が１．２０よりも小さい場合でも「バンディングむら」が目立ちにくいことがあるが、文字等の画像にボケや滲みが発生し、ベタ画像部についてはざらつき感のある画像となる。
印字品位が優れ、ノズル単位のバラツキや紙送り量のバラツキに起因するスジ（バンディング）が目立たない画像が得られるのは、解像度に対するドットサイズと、ドットの形状係数の両方が適切な範囲にある場合である。 As described above, if the dot shape factor is 1.50 or less, a recorded image with high sharpness without blurring or blurring in the peripheral portion of an image such as a character can be obtained. If the shape factor is greater than 1.50,

Even if the value of is less than 1.20, “uneven banding” may be inconspicuous, but blurring and blurring occur in images such as characters, and the solid image portion has a rough feeling.
The print quality is excellent, and the image with inconspicuous streaks (banding) due to nozzle unit variation and paper feed amount variation can be obtained because both the dot size with respect to the resolution and the dot shape factor are in the appropriate range. Is the case.

  Dot shape and dot diameter are determined by various factors such as ink physical properties, ink droplet size, ink droplet ejection conditions, and ink absorbency (speed, capacity, properties of the receiving layer surface) of the recording medium (paper). Is done. When designing a recording system, it is necessary to optimally set the combination of these elements.

Next, a recording liquid cartridge containing a recording liquid and an ink jet recording apparatus including the recording liquid cartridge according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the following configuration examples. .
FIG. 1 is a schematic front view of a mechanism part of a serial type ink jet recording apparatus equipped with an ink cartridge having a recording liquid storage part storing a recording liquid of the present invention.
The mechanism part of this ink jet recording apparatus lays a main support guide rod (3) and a sub support guide rod (4) between side plates (1) and (2) on both sides in a substantially horizontal positional relationship, The carriage unit (5) is slidably supported in the main scanning direction by the support guide rod (3) and the secondary support guide rod (4). The carriage unit (5) has four heads (6) for ejecting yellow (Y) ink, magenta (M) ink, cyan (C) ink and black (Bk) ink, respectively, and their ejection surfaces (nozzles). The surface (6a) is mounted facing downward, and on the upper side of the head (6) of the carriage unit (5) is an ink supply body of each color for supplying ink to each of the four heads (6). Four ink cartridges (7y), (7m), (7c), and (7k) are mounted interchangeably.

  The carriage unit (5) is a timing belt (11) stretched between a drive pulley (drive timing pulley) (9) and a driven pulley (idler pulley) (10) rotated by the main scanning motor (8). The carriage (5), that is, the four heads (6) are moved in the main scanning direction by driving and controlling the main scanning motor (8).

  Further, subframes (13) and (14) are erected on the bottom plate (12) connecting the side plates (1) and (2), and the paper (16) is mainly placed between the subframes (13) and (14). A conveyance roller (15) for feeding in the sub-scanning direction orthogonal to the scanning direction is rotatably held. A sub-scanning motor (17) is disposed on the side of the sub-frame (14), and the rotation of the sub-scanning motor (17) is transmitted to transmit the rotation of the sub-scanning motor (17) to the transport roller (15). A gear (18) fixed to the shaft and a gear (19) fixed to the shaft of the conveying roller (15) are provided.

  Further, between the side plate (1) and the subframe (12), a reliability maintenance / recovery mechanism (hereinafter referred to as “subsystem”) (21) of the head (6) is disposed. The subsystem (21) holds four cap means (22) for capping the ejection surface of each head (6) by a holder (23), and the holder (23) is pivoted to a link member (24). By holding the housing of the ink suction pump in a swingable manner, the carriage unit (5) comes into contact with the engaging portion (25) provided in the holder (23) by the movement of the carriage unit (5) in the main scanning direction. As the carriage unit (5) moves, the holder (23) lifts up, and the cap means (22) caps the ejection surface (6a) of the inkjet head (6), and the carriage unit (5) moves toward the printing area. As the carriage unit (5) moves, the holder (23) lifts down and the cap means (22) moves to the inkjet head ( ) It is away from the discharge surface of the (6a).

The cap means (22) is connected to the suction pump (27) via the suction tube (26), and forms an atmosphere opening, and communicates with the atmosphere via the atmosphere opening tube and the atmosphere opening valve. ing. The suction pump (27) discharges the sucked waste liquid to a waste liquid storage tank (not shown) through a drain tube or the like.
Further, on the side of the holder (23), there is a wiper blade (28) which is a wiping means made of an elastic member such as a fiber member, a foam member or rubber for wiping the discharge surface (6a) of the inkjet head (6). The blade arm (29) is attached to an arm (29) and is pivotally supported so as to be swung by rotation of a cam rotated by a driving means (not shown).

Next, the ink cartridge (7) will be described with reference to FIGS.
Here, FIG. 2 is an external perspective view of the ink cartridge before being loaded into the recording apparatus, and FIG. 3 is a front sectional view of the ink cartridge.
As shown in FIG. 3, the ink cartridge (7) includes an ink absorber (42) that absorbs ink of a required color in a cartridge body (41). The cartridge body (41) is formed by adhering or welding an upper lid member (44) to an upper opening of a case (43) having a wide opening at the upper portion, and is made of, for example, a resin molded product. The ink absorber (42) is made of a porous material such as a urethane foam, and after being compressed and inserted into the cartridge body (41), the ink is absorbed.

An ink supply port (45) for supplying ink to the recording head (6) is formed at the bottom of the case (43) of the cartridge body (41), and a seal ring (45) is formed on the inner peripheral surface of the ink supply port (45). 46). The upper lid member (44) has an air opening (47).
The cartridge main body (41) is closed with the ink supply port (45) in a state before being loaded, and the case (43) with pressure applied to the wide side wall during handling of the cartridge during loading or transportation, or during vacuum packaging. ) Is compressed and deformed, and the cap member (50) is attached to prevent the internal ink from leaking.

Further, as shown in FIG. 2, the air opening (47) is sealed by attaching a film-like sealing member (55) having an oxygen permeability of 100 ml / m ² or more to the upper lid member (44). The sealing member (55) is sized to seal the plurality of grooves (48) formed around it together with the atmosphere opening (47). In this way, the air opening (47) is sealed with the sealing member (55) having an oxygen permeability of 100 ml / m ² or more, so that the ink cartridge (7) is made of a packaging member such as a non-permeable aluminum laminate film. By wrapping in a reduced pressure state, gas is contained in the ink due to the atmosphere in the space (A) (see FIG. 3) that is formed between the ink absorber (42) and the cartridge body (41) when the ink is filled. Even when dissolved, the air in the ink is discharged to the space between the packaging member outside the cartridge body (41) having a high degree of vacuum through the seal member (55), and the degree of deaeration of the ink is improved.

FIG. 4 shows an example of the configuration of a recording cartridge provided with a recording liquid storage unit that stores the recording liquid of the present invention and a head unit for discharging recording droplets.
That is, the recording unit (30) is of a serial type, and includes an ink jet head (6), an ink tank (41) that stores a recording liquid supplied to the ink jet head (6), and the ink tank (41). ) The main part is composed of a lid member that seals the inside. The inkjet head (6) is formed with a large number of nozzles (32) for discharging recording liquid. The recording liquid is guided from the ink tank (41) to a common liquid chamber (not shown) via an ink supply pipe (not shown), and the nozzles according to an electrical signal from the recording apparatus main body input from the electrode (31). (32). This type of recording unit has a structure suitable for a head of a type that can be manufactured at low cost, a head called a thermal method or a bubble method, which uses thermal energy as a driving power source. Since the recording liquid of the present invention improves the wettability to the thermal element by adding a polyol or glycol ether having 8 to 11 carbon atoms in a recording method such as bubble or thermal method, even with a small amount of addition. Discharge stability and frequency stability are obtained, and safety is high, which is very suitable.

FIG. 5 shows an external perspective view of another specific example of the ink cartridge.
In the ink cartridge (501) shown in FIG. 5, the ink bag (502) is stored in the case (503), and the case (503) has three components (511), (512), and (513). And is fixed by a screw member (582). Accordingly, it is possible to prevent the ink cartridge (501) from being naturally decomposed when being attached to or detached from the recording apparatus main body.
The ink cartridge (501) shown in FIG. 5 has an ink supply port (525), an opening (553) for the ink supply port (525), a recess (541) for attaching to and detaching from the recording apparatus main body, and a hook. Part (542), guide parts (544), (545) are provided, and color identification means (564) for representing the color of the ink is further provided.

Next, an example of an ink jet recording apparatus using the ink cartridge (501) described above will be described with reference to FIG. FIG. 6 is a specific schematic configuration diagram for explaining the overall configuration of the mechanism of the ink jet recording apparatus.
This ink jet recording apparatus records (forms) an apparatus main body (101), a paper feed tray (102) for loading paper mounted on the apparatus main body (101), and an image mounted on the apparatus main body (101). And a paper discharge tray (103) for stocking the printed paper. The upper surface of the upper cover (111) of the apparatus main body (101) is a substantially flat surface, and the front surface (112) of the front cover of the apparatus main body (101) is inclined obliquely downward and rearward with respect to the upper surface. On the lower side of the front surface (112), a paper discharge tray (103) and a paper feed tray (102) projecting forward (front side) are provided.

In the apparatus main body (101), as shown in FIG. 6, a carriage (133) is moved in the main scanning direction by a guide rod (131), which is a guide member horizontally mounted on left and right side plates (not shown), and a stay (132). It is slidably held and moved and scanned by a main scanning motor (not shown).
The carriage (133) includes a plurality of recording heads (134) including four inkjet heads that eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). The ink discharge ports are arranged in a direction crossing the main scanning direction, and are mounted with the ink droplet discharge direction facing downward.

As the ink jet head constituting the recording head (134), a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes a phase change caused by film boiling of a liquid using an electrothermal transducer such as a heating resistor, a metal phase caused by a temperature change A shape memory alloy actuator using a change, an electrostatic actuator using an electrostatic force, or the like as an energy generating means for discharging ink can be used.
The carriage (133) is equipped with a sub tank (135) for each color for supplying ink of each color to the recording head (134). Ink is supplied to the sub tank (135) from an ink cartridge (1) according to the present invention loaded in an ink cartridge loading section via an ink supply tube (not shown).

  On the other hand, as a paper feeding unit for feeding the paper (142) stacked on the paper stacking unit (pressure plate) (141) of the paper feed tray (103), 1 sheet (142) is fed from the paper stacking unit (141). Opposed to the half-moon roller (sheet feeding roller) (143) and sheet feeding roller (143) for separating and feeding one sheet at a time, a separation pad (144) made of a material having a large friction coefficient is provided, and this separation pad (144) is fed. It is biased toward the paper roller (143) side.

  Then, as a transport unit for transporting the paper (142) fed from the paper feed unit on the lower side of the recording head (134), a transport belt (for electrostatically attracting and transporting the paper (142)) 151), a counter roller (152) for conveying the paper (142) sent from the paper supply unit via the guide (145) between the conveyance belt (151), and a substantially vertical upper part. A conveyance guide (153) for changing the direction of the sheet (142) by approximately 90 ° to follow the conveyance belt (151), and a leading edge biased toward the conveyance belt (151) by the pressing member (154). A pressure roller (155). Further, a charging roller (156) which is a charging unit for charging the surface of the conveying belt (151) is provided.

  Here, the conveyance belt (151) is an endless belt, and is configured to be looped around the conveyance roller (157) and the tension roller (158) in the belt conveyance direction. This transport belt (151) is made of, for example, a surface layer that becomes a sheet adsorbing surface formed of a resin material having a thickness of about 40 μm that is not subjected to resistance control, for example, a fluororesin ETFE pure material, and a carbon material that is the same material as the surface layer. And a back layer (medium resistance layer, earth layer) that has been subjected to resistance control.

In addition, a guide member (161) is disposed on the back side of the conveyance belt (151) so as to correspond to a printing area by the recording head (134).
Further, as a paper discharge unit for discharging the paper (142) recorded by the recording head (134), a separation claw (171) for separating the paper (142) from the transport belt (151), and paper discharge A roller (172) and a paper discharge roller (173) are provided, and a paper discharge tray (103) is provided below the paper discharge roller (172).

  A double-sided paper feeding unit (181) is detachably attached to the back surface of the apparatus main body (101). The double-sided paper feeding unit (181) takes in the paper (142) returned by the reverse rotation of the transport belt (151), reverses it, and feeds it again between the counter roller (152) and the transport belt (151). . In addition, a manual paper feeding unit (182) is provided on the upper surface of the double-sided paper feeding unit (181).

  In the ink jet recording apparatus configured as described above, the paper (142) is separated and fed one by one from the paper feeding unit, and the paper (142) fed substantially vertically upward is guided by the guide (145) and conveyed. It is sandwiched between the belt (151) and the counter roller (152) and conveyed, and the leading end is guided by the conveying guide (153) and is pressed against the conveying belt (151) by the leading pressure roller (155). 90 ° conveyance direction is changed.

At this time, the conveying belt (157) is charged by the charging roller (156), and the sheet (142) is electrostatically attracted to the conveying belt (151) and conveyed. Therefore, by driving the recording head (134) according to the image signal while moving the carriage (133), ink droplets are ejected onto the stopped sheet (142) to record one line, and the sheet ( 142), the next line is recorded after a predetermined amount is conveyed. Upon receiving a recording end signal or a signal that the rear end of the paper (142) has reached the recording area, the recording operation is finished and the paper (142) is discharged to the paper discharge tray (103). In the case of using a conveyor belt that uses electrostatic attraction, the current technology has a large variation in the amount of movement mainly in the sub-scanning direction (paper feeding direction) in each scanning, that is, a variation caused by the paper feeding accuracy. It is necessary to increase the dot diameter.
When a near-end ink remaining amount in the sub tank (135) is detected, a required amount of ink is supplied from the ink cartridge (1) to the sub tank (135).

  Since this ink jet recording apparatus includes the ink cartridge (1) according to the present invention, when the ink cartridge (1) is also used up, the casing (3) is disassembled and only the ink bag (2) inside is replaced. In addition, even when the ink cartridge (1) is vertically placed and has a front loading configuration, the ink can be stably supplied, so that the upper portion of the apparatus main body (101) is closed and installed, for example, The ink cartridge (1) can be easily replaced even when stored in a rack or when an object is placed on the upper surface of the apparatus main body (101).

Here, the serial type ink jet recording apparatus as described above has been described, but the recording liquid of the present invention has the same or a fraction of the density as the target image resolution with an arbitrary arrangement of nozzles such as a staggered pattern. It is also possible to apply the present invention to a recording apparatus having a so-called line head that is integrated and arranged beyond the width of the recording medium.
The recording device here may be an apparatus having a complex function in combination with a fax machine, a scanner, a telephone, etc., as well as a PC (host computer) and a digital camera output printer.
When the ink jet recording apparatus is used as an output printer of a PC, the ink jet recording apparatus is connected to the PC via a cable and controlled by driver software installed in the PC.

Next, the ink preferably used in the present invention will be described.
First, the ink used in the present invention is preferably a low surface tension aqueous ink or ink set having a surface tension at 25 ° C. of 40 mN / m or less. This is because most of the recording materials can be obtained by adjusting the surface tension of the ink to 40 mN / m or less as a result of investigations by the present inventors on various means for improving the drying property of the recorded image. This is based on the finding that rapid osmotic drying is possible. Also, by setting the ink surface tension to 40 mN / m or less, wetting of the ink to the head member is improved, and the frequency response is improved even with high viscosity ink of 8 mPa · sec (25 ° C.) or more, and the ejection stability. Is significantly improved. This low surface tension ink can be achieved by using a polyol or glycol ether having 8 to 11 carbon atoms and an anionic or nonionic surfactant.

  Second, in the present invention, the print quality is remarkably improved by using a high-viscosity ink or ink set of preferably 5 mPa · sec or more, more preferably 8 mPa · sec (25 ° C.) or more. The low-viscosity ink of about 3 mPa · sec (25 ° C.) used in conventional ink jet printers has about 70% by weight of water in the ink, but the high-viscosity ink of about 8 mPa · sec (25 ° C.) is about 50%. The moisture evaporation rate when ink droplets land on the paper surface becomes 2.0 to 3.0 times higher. For this reason, the speed at which high-concentration pigments agglomerate on the paper surface increases, and there is almost no bleeding.

  Third, in the present invention, the color material concentration in the ink is preferably 8% by weight or more, more preferably 10% by weight or more in terms of solid content. By increasing the polymer emulsion concentration or the pigment concentration, the viscosity of the ink is increased, the pigment tends to stay on the surface of the ink receiving layer of the recording medium, and the color density and color tone are improved.

  Fourthly, in the present invention, glycerin, 1,3-butanediol, triethylene glycol, 1,6 rather than a conventionally used low viscosity wetting agent in which ethylene glycol (diethylene glycol) and glycerin are mixed are used. -High viscosity wetting with glycerin mixed with at least one high viscosity wetting agent selected from hexanediol, propylene glycol, 1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, trimethylolethane It is preferable to use an agent. When a high viscosity wetting agent is used, a high viscosity ink can be obtained in combination with a high pigment concentration.

A preferred ink composition used in the present invention is a recording ink having the following constitution and an ink viscosity of 5 mPa · sec or more, preferably 8 mPa · sec (25 ° C.) or more. A colorant for printing and water for dispersing the same are essential components, and wetting agents added as necessary, water-soluble organic solvents, anionic or nonionic surfactants, emulsions, preservatives, pH adjustments. Consists of formulations. Wetting agents 1 and 2 are mixed in order to make use of the characteristics of each wetting agent and to adjust the viscosity, but wetting agents 1 and 2 are not necessarily required to be combined.
(I) Colorant (II) Wetting agent 1 (Glycerin)
(III) Wetting agent 2 (1,3-butanediol, triethylene glycol,
1,6-hexanediol, propylene glycol,
1,5-pentanediol, diethylene glycol,
Dipropylene glycol, trimethylolpropane,
(At least one selected from trimethylolethane)
(IV) Water-soluble organic solvent (V) Anion or nonionic surfactant (VI) Polyol or glycol ether having 8 to 11 carbon atoms (VII) Preservative (VIII) pH adjuster (IX) Pure water

Hereinafter, the components of each ink that can be preferably used in the present invention will be described.
As the colorant (coloring material), known direct dyes, acid dyes, reactive dyes, disperse dyes, pigments and the like can be used, but pigments excellent in water resistance and light resistance of recorded images are preferable.
As a black ink coloring material, for example, carbon black is used. Carbon black produced by a furnace method, a channel method, or the like, has a primary particle diameter of 15 nm to 40 nm, a specific surface area by a BET adsorption method of 50 to 300 m <2> / g, Those having a pH of 2 to 9 are preferably used, and acidic carbon black having a pH of 6 or less is particularly preferred at a high concentration. Further, carbon black treated with hypochlorous acid, carbon black treated with a sulfonating agent, carbon black treated with a diazonium compound and introduced with an anionic dissociating group such as sulfonic acid or carboxylic acid, so-called self-dispersing carbon black is preferred.

Black ink using self-dispersing carbon black is excellent in ejection stability and has excellent image density and character quality when recorded on plain paper, but recording with an ink absorption layer on a substrate such as glossy paper When recording on a medium, the scratch resistance may be insufficient. For the purpose of supplementing the scratch resistance, a resin emulsion may be added to self-dispersing carbon black.
The resin emulsion means an emulsion in which the continuous phase is water and the dispersed phase is the following resin component. Examples of the resin component in the dispersed phase include acrylic resins, vinyl acetate resins, styrene-butadiene resins, vinyl chloride resins, acrylic-styrene resins, butadiene resins, and styrene resins.

According to a preferred embodiment of the present invention, the resin is preferably a polymer having both a hydrophilic part and a hydrophobic part. The particle size of these resin components is not particularly limited as long as an emulsion is formed, but is preferably about 150 nm or less, more preferably about 5 to 100 nm.
These resin emulsions can be obtained by mixing resin particles in water, optionally with a surfactant. For example, an acrylic resin or a styrene-acrylic resin emulsion can be obtained by mixing these resins and a surfactant in water.
The mixing ratio (weight ratio) of the resin component and the surfactant is usually preferably about 10: 1 to 5: 1. When the amount of the surfactant used is less than the above range, it is difficult to form an emulsion, and when it exceeds the above range, the water resistance of the ink composition tends to decrease or the permeability tends to deteriorate, such being undesirable.
In addition, the ratio of the resin and water as the dispersed phase component of the emulsion is suitably in the range of 60 to 400 parts by weight, preferably 100 to 200 parts by weight with respect to 100 parts by weight of the resin.

  Commercially available resin emulsions include Microgel E-1002, E-5002 (styrene-acrylic resin emulsion, manufactured by Nippon Paint Co., Ltd.), Boncoat 4001 (acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.), Boncoat 5454 ( Styrene-acrylic resin emulsion, manufactured by Dainippon Ink Chemical Co., Ltd.), SAE-1014 (styrene-acrylic resin emulsion, manufactured by Nippon Zeon Co., Ltd.), Cybinol SK-200 (acrylic resin emulsion, manufactured by Seiden Chemical Co., Ltd.), etc. Can be mentioned.

In the present invention, when a resin emulsion is added, the resin component is preferably contained in an amount of 0.1 to 40% by weight, more preferably 1 to 25% by weight of the ink composition.
The resin emulsion has the property of thickening and aggregating, has the effect of suppressing the penetration of the coloring components, and further promoting the fixing to the recording material. In addition, depending on the type of resin emulsion, a film is formed on the recording material, which has the effect of improving the scratch resistance of the printed matter.

  The color material for color ink is made of a polymer emulsion in which polymer fine particles contain a water-insoluble or hardly soluble color material. In the present invention, “containing a color material” means either or both of a state in which a color material is enclosed in polymer fine particles and a state in which the color material is adsorbed on the surface of the polymer fine particles. In this case, it is not necessary for all of the color material blended in the ink of the present invention to be enclosed or adsorbed in the polymer fine particles, and the color material is dispersed in the emulsion as long as the effects of the present invention are not impaired. Also good. The color material is not particularly limited as long as it is water-insoluble or hardly water-soluble and can be adsorbed by the polymer.

  In the present invention, water-insoluble or poorly water-soluble means that the coloring material does not dissolve 10 parts by weight or more with respect to 100 parts by weight of water at 20 ° C. This means that no separation or sedimentation is observed. Examples of the coloring material include dyes such as oil-soluble dyes and disperse dyes, pigments, and the like. Oil-soluble dyes and disperse dyes are preferable from the viewpoint of good adsorption and encapsulation, but pigments are preferably used from the light resistance of the obtained image.

  Each dye used in the present invention is preferably dissolved in an organic solvent, for example, a ketone solvent in an amount of 2 g / liter or more, preferably 20 to 600 g / liter, from the viewpoint of efficiently impregnating the polymer fine particles. Is more preferable.

  The pigment for color ink is for yellow ink and C.I. I. Pigment Yellow 1 (Fast Yellow G), 3, 12 (Disazo Yellow AAA), 13, 14, 17, 23, 24, 34, 35, 37, 42 (Yellow Iron Oxide), 53, 55, 74, 81, 83 (Disazo Yellow HR), 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 128, 138, 150, 153 and the like can be used.

  For magenta and C.I. I. Pigment Red 1, 2, 3, 5, 17, 22 (Brilliant First Scarlet), 23, 31, 38, 48: 2 (Permanent Red 2B (Ba)), 48: 2 (Permanent Red 2B (Ca)), 48 : 3 (Permanent Red 2B (Sr)), 48: 4 (Permanent Red 2B (Mn)), 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81 (Rhodamine 6G Lake), 83, 88, 92, 101 (Bengara), 104, 105, 106, 108 (Cadmium Red), 112, 114, 122 (Dimethylquinacridone), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 209, 2 It can be used 9 like.

  For cyan, C.I. I. Pigment Blue 1, 2, 15 (copper phthalocyanine blue R), 15: 1, 15: 2, 15: 3 (phthalocyanine blue G), 15: 4, 15: 6 (phthalocyanine blue E), 16, 17: 1, 56, 60, 63, etc. can be used.

In addition, the following pigments can be used alone or as a mixture for red, green, and blue as intermediate colors. The following pigments can also be used for the above-mentioned magenta and cyan toning.
C. I. Pigment red 177, 194, 224, C.I. I. Pigment orange 43, C.I. I. Pigment violet 3, 19, 23, 37, C.I. I. Pigment Green 7, 36.
Examples of other suitable colored pigments are described in The Color Index, 3rd edition (The Society of Dyer's and Colorists, 1982).

In addition, when using a pigment as a coloring agent, the said dye can also be used together for a complementary color, toning, etc.
The blending amount of the coloring material is preferably about 10 to 200% by weight, particularly preferably about 25 to 150% by weight with respect to the weight of the polymer in relation to the blending amount of the polymer.
As the polymer that forms the polymer emulsion, for example, vinyl polymers, polyester polymers, polyurethane polymers, and the like can be used. Particularly preferred polymers are vinyl polymers and polyester polymers, and polymers disclosed in JP-A Nos. 2000-53897, 2000-53898, and 2001-139849 are exemplified.

According to a preferred embodiment of the present invention, the average particle size of the polymer fine particles containing these coloring materials is most preferably 0.16 μm or less in the ink.
The content of the polymer fine particles in the ink is preferably about 8 to 20% by weight, more preferably about 8 to 12% by weight in terms of solid content.

  Regarding the wetting agent and the water-soluble organic solvent, the ink of the present invention uses water as a liquid medium. In order to make the ink have desired physical properties, to prevent the ink from drying, and to improve the dispersion stability. For the purpose of improving, for example, the following water-soluble organic solvents are used. A plurality of these water-soluble organic solvents may be used in combination.

Specific examples of the wetting agent and the water-soluble organic solvent include the following.
Ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetraethylene glycol, hexylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6-hexanediol, glycerol, Polyhydric alcohols such as 1,2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3-butanetriol, petriol;
Polyhydric alcohol alkyl ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether;
Polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether;
Nitrogen-containing heterocyclic compounds such as 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone;
Amides such as formamide, N-methylformamide, N, N-dimethylformamide;
Amines such as monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, triethylamine;
Sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, thiodiethanol;
Propylene carbonate, ethylene carbonate and the like.

  Among these organic solvents, diethylene glycol, thiodiethanol, polyethylene glycol 200 to 600, triethylene glycol, glycerol, 1,2,6-hexanetriol, 1,2,4-butanetriol, petriol, 1,5-pentane Diol, 2-pyrrolidone and N-methyl-2-pyrrolidone are preferred. These are excellent in solubility and prevention of poor jetting characteristics due to water evaporation.

The other wetting agent preferably contains sugar. Examples of saccharides include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides) and polysaccharides, preferably glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, Examples include lactose, sucrose, trehalose, and maltotriose. Here, the polysaccharide means a saccharide in a broad sense, and is used to include a substance that exists widely in nature such as α-cyclodextrin and cellulose.
The derivatives of these saccharides are represented by the reducing sugars of the saccharides described above (for example, sugar alcohol (general formula HOCH ₂ (CHOH) nCH ₂ OH (where n is an integer of 2 to 5)). ), Oxidized sugars (eg, aldonic acid, uronic acid, etc.), amino acids, thioic acids, etc. Particularly preferred are sugar alcohols, and specific examples include maltitol, sorbit, and the like.
The content of these saccharides is suitably 0.1 to 40% by weight, preferably 0.5 to 30% by weight of the ink composition.

The ratio of pigment to wetting agent has a great influence on the stability of ink ejection from the head. If the pigment solid content is high but the amount of the wetting agent is small, water evaporation near the ink meniscus of the nozzle advances and discharge failure occurs.
The blending amount of the wetting agent is preferably 10 to 50% by weight. On the other hand, the polymer fine particles containing the coloring material are preferably 8% by weight or more, more preferably 8 to 20% by weight. The ratio of both solid contents is preferably 0.5 to 6.25, more preferably 2.0 to 6.0, and most preferably 3.0 to 5.0. Ink within this range has very good drying, storage and reliability tests.

As the surfactant, an anionic surfactant or a nonionic surfactant is used. A surfactant that does not impair dispersion stability is selected depending on the combination of the type of colorant, the wetting agent, and the water-soluble organic solvent.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, polyoxyethylene alkyl ether sulfate, and the like.
Nonionic surfactants include, for example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl amines, polyoxyethylene alkyl amides, and the like. Can be mentioned.
Acetylene glycol surfactants are 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl. An acetylene glycol type such as -1-hexyn-3-ol (for example, Surfynol 104, 82, 465, 485 or TG manufactured by Air Products (USA)) can be used, and particularly Surfinol 465, 104 and TG. Indicates good print quality.
The surfactants can be used alone or in combination of two or more.

  In the present invention, wettability to recording paper can be improved by using a surfactant. Preferred surfactants include polyoxyethylene alkyl ether acetates, dialkyl sulfosuccinates, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene polyoxypropylene block copolymers, and acetylene glycol surfactants. Is mentioned. More specifically, examples of the anionic surfactant include polyoxyethylene alkyl ether acetates represented by the following general formula (I) and / or 5 to 16 branched carbon chains represented by the following general formula (II). Examples thereof include dialkylsulfosuccinic acid having an alkyl chain, and by using these, the properties of plain paper are improved, and further the dissolution / dispersion stability of the colorant is obtained.

（Ｒ_１：炭素数６〜１４の分岐してもよいアルキル基、ｍ＝３〜１２、Ｍ：アルカリ金属イオン、第４級アンモニウム、第４級ホスホニウム、アルカノールアミン）

(R ₁ : alkyl group having 6 to 14 carbon atoms which may be branched, m = 3 to 12, M: alkali metal ion, quaternary ammonium, quaternary phosphonium, alkanolamine)

（Ｒ_２：炭素数５〜１６の分岐したアルキル基、Ｍ：アルカリ金属イオン、第４級アンモニウム、第４級ホスホニウム、アルカノールアミン）

(R ₂ : branched alkyl group having 5 to 16 carbon atoms, M: alkali metal ion, quaternary ammonium, quaternary phosphonium, alkanolamine)

Table 1 specifically shows the surfactants (I) and (II) used in the present invention in free acid form.

  Furthermore, by using lithium ions, quaternary ammonium ions and quaternary phosphonium ions represented by the following general formula as counter ions of the surfactant of the present invention, the surfactant exhibits excellent dissolution stability.

（式中、Ｚは窒素又はリンを表し、Ｒ_３〜Ｒ_６は独立に水素、炭素数１〜４のアルキル基、ヒドロキシアルキル基、またはハロゲン化アルキル基を表す。）

(In the formula, Z represents nitrogen or phosphorus, and R _{3 to} R ₆ independently represent hydrogen, an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, or a halogenated alkyl group.)

  Preferred nonionic surfactants include polyoxyethylene alkylphenyl ethers represented by the following general formula (III), polyoxyethylene alkyl ethers represented by the following general formula (IV), general formulas (V) and (V ′ And acetylene glycol surfactants represented by the following general formula (VI). By using these together, penetrability can be mentioned as a further synergistic effect, and this makes it possible to reduce ink at the color boundary and to obtain ink with less character bleeding.

（Ｒは分岐しても良い炭素数６〜１４の炭化水素基、ｋ＝５〜２０）

(R is a hydrocarbon group having 6 to 14 carbon atoms which may be branched, k = 5 to 20)

（Ｒは分岐しても良い炭素数６〜１４の炭化水素基、ｎ＝５〜２０）

(R is a hydrocarbon group having 6 to 14 carbon atoms which may be branched, n = 5 to 20)

（Ｒ’は炭素数６〜１４の炭化水素基、ｍ≦２０、ｎ≦２０）

(R ′ is a hydrocarbon group having 6 to 14 carbon atoms, m ≦ 20, n ≦ 20)

（ｐ、ｑ＝０〜４０）

(P, q = 0-40)

Ink storage stability can be obtained by setting the pH of the ink to 6 or more, and many copy papers and sticky notes used in offices have a pH of 5-6. The ink is discharged from a fine discharge port of 9 to 60 μm and is ejected as a droplet having a weight of 3 ng to 50 ng at a rate of 5 to 20 m / s, and the adhesion amount in a single color is changed from 1.5 g / m ² to 30 g / m ^2. By recording on a so-called plain paper having a Steecht sizing degree of 3 seconds or more according to the JIS P-8122 test method, it is possible to provide a recording method for forming a high-quality and high-resolution recorded image. However, when the surfactant represented by the general formula (II) is used, it is preferable to adjust the pH to 6 to 9 because if the pH is 9 or more, physical properties change due to decomposition during storage is likely to occur.

  The addition amount of the surfactant represented by the general formulas (I), (II), (III), (IV), (V), (V ′), and (VI) that can be used in the present invention is 0. It is possible to provide the desired permeability for the ink properties required by the printer system between 05 and 10% by weight. Here, if it is less than 0.05% by weight, bleeding occurs at the boundary between the two-color overlapping portions in any case, and if it is added more than 10% by weight, the compound itself may be easily precipitated at a low temperature, resulting in poor reliability. Become.

  The surface tension in the present invention is an index indicating the permeability to paper. In particular, the surface tension indicates the dynamic surface tension in a short time of 1 second or less after the surface is formed, and is different from the static surface tension measured by the saturation time. . As a measuring method, any method can be used as long as it can measure a dynamic surface tension of 1 second or less by a conventionally known method described in JP-A-63-131237. In the present invention, a Wilhelmy type suspension plate type surface is used. Measurement was performed using a tensiometer. When the value of the surface tension is preferably 40 mN / m or less, more preferably 35 mN / m or less, excellent fixing properties and drying properties can be obtained.

The polyol or glycol ether having 8 to 11 carbon atoms used in the present invention is a partially water-soluble polyol and / or glycol having a solubility of preferably less than 0.1 to 4.5% by weight in water at 25 ° C. By adding 0.1 to 10.0% by weight, preferably 0.1 to 10.0% by weight based on the total weight of the recording ink, the wettability of the ink to the thermal element is improved. Frequency stability is obtained.
The following are mentioned as these preferable examples.
(I) 2-ethyl-1,3-hexanediol Solubility: 4.2% by weight (20 ° C.)
(II) 2,2,4-Trimethyl-1,3-pentanediol Solubility: 2.0% by weight (25 ° C.)
A penetrant composed of a polyol or glycol ether having a solubility of less than 0.1 to 4.5% by weight in water at 25 ° C. has an advantage that it has a very high permeability instead of a low solubility. Therefore,
A highly penetrating ink can be obtained by combining a penetrant having a solubility of less than 0.1 to 4.5% by weight in water at 25 ° C. with another solvent or another surfactant. It becomes possible to create.

Conventionally known additives can be added to the ink of the present invention in addition to the colorant, solvent, surfactant and the like.
For example, as a preservative and antifungal agent, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol and the like can be used.
As the pH adjuster, any substance can be used as long as the pH can be adjusted to 7 or more without adversely affecting the prepared ink.
Examples thereof include amines such as diethanolamine and triethanolamine, hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide and potassium hydroxide, ammonium hydroxide, quaternary ammonium hydroxide, and quaternary phosphonium. Examples thereof include carbonates of alkali metals such as hydroxide, lithium carbonate, sodium carbonate, and potassium carbonate.
Furthermore, as a chelating reagent, for example, sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate and the like can be used.
Further, as the rust preventive agent, for example, acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite and the like can be used.
Depending on the purpose, a water-soluble ultraviolet absorber, a water-soluble infrared absorber, or the like can be added.

  Examples and Comparative Examples of the present invention are shown below, but the present invention is not limited to these.

<Create ink>
Colorant Example 1
Preparation of phthalocyanine pigment-containing polymer fine particle dispersion Preparation Example 3 of JP-A No. 2001-139849 was additionally tested, and specifically, the following operation was performed.
(1) Preparation of polymer solution After thoroughly substituting nitrogen gas into a 1 L volume flask equipped with a mechanical stirrer, thermometer, nitrogen gas inlet tube, reflux tube and dropping funnel, 11.2 g of styrene, acrylic acid 2 0.8 g, 12.0 g of lauryl methacrylate, 4.0 g of polyethylene glycol methacrylate, 4.0 g of styrene macromer (manufactured by Toa Gosei Co., Ltd., trade name: AS-6) and 0.4 g of mercaptoethanol are charged to 65 ° C. did.
Next, styrene 100.8 g, acrylic acid 25.2 g, lauryl methacrylate 108.0 g, polyethylene glycol methacrylate 36.0 g, hydroxyethyl methacrylate 60.0 g, styrene macromer (manufactured by Toagosei Co., Ltd., trade name: AS-6) ) A mixed solution of 36.0 g, mercaptoethanol 3.6 g, azobisdimethylpareronitrile 2.4 g and methyl ethyl ketone 18 g was dropped into the flask over 2.5 hours.
After completion of dropping, a mixed solution of 0.8 g of azobisdimethylvaleronitrile and 18 g of methyl ethyl ketone was dropped into the flask over 0.5 hours. After aging at 65 ° C. for 1 hour, 0.8 g of azobisdimethylvaleronitrile was added, and further aging was performed for 1 hour.
After completion of the reaction, 364 g of methyl ethyl ketone was added to the flask to obtain 800 g of a polymer solution having a concentration of 50% by weight.
(2) Preparation of aqueous dispersion of polymer fine particles 28 g of polymer solution obtained in (1) above, phthalocyanine pigment (manufactured by Dainippon Ink & Chemicals, Inc., trade name: TGR-SD) 26 g, 1 mol / L of water After sufficiently stirring 13.6 g of an aqueous potassium oxide solution, 20 g of methyl ethyl ketone and 30 g of ion-exchanged water, the mixture was kneaded 20 times using a three-roll mill. The obtained paste was put into 200 g of ion-exchanged water and sufficiently stirred, and then methyl ethyl ketone and water were distilled off using an evaporator to obtain a blue polymer fine particle dispersion.
The average particle diameter (D50%) of the fine polymer particles measured by Microtrac UPA was 93 nm.

Colorant Example 2
Preparation of dimethylquinacridone pigment-containing polymer fine particle dispersion Colorant Example 1 A reddish purple polymer fine particle dispersion was obtained in the same manner as in Colorant Example 1 except that the phthalocyanine pigment was changed to Pigment Red 122. The average particle diameter (D50%) of the polymer fine particles measured by Microtrac UPA was 127 nm.

Colorant Example 3
Preparation of Monoazo Yellow Pigment-Containing Polymer Fine Particle Dispersion Colorant Example 1. A yellow polymer fine particle dispersion was obtained in the same manner as in Colorant Example 1 except that the phthalocyanine pigment was changed to Pigment Yellow 74. The average particle diameter (D50%) of the polymer fine particles measured by Microtrac UPA was 76 nm.

Colorant Example 4
Carbon black dispersion treated with diazo compound (self-dispersion type)
100 g of carbon black having a surface area of 230 m ² / g and a DBP oil absorption of 70 ml / 100 g and 34 g of p-amino-N-benzoic acid are mixed and dispersed in 750 g of water, and 16 g of nitric acid is added dropwise thereto and stirred at 70 ° C. did. After 5 minutes, a solution of 11 g of sodium nitrite dissolved in 50 g of water was added, and the mixture was further stirred for 1 hour. The resulting slurry was diluted 10 times and centrifuged to remove coarse particles, the pH was adjusted with diethanolamine to pH 8-9, desalted and concentrated with an ultrafiltration membrane, and a carbon black dispersion having a pigment concentration of 15% by weight. It was. This was made into carbon black dispersion 1 with a polypropylene 0.5 μm filter. The average particle size (D50%) measured by Microtrac UPA was 99 nm.

Colorant Example 5
Carbon black dispersion treated with hypochlorous acid (self-dispersion type)
After mixing 300 g of commercially available acidic carbon black having a pH of 2.5 (trade name Monarch 1300, manufactured by Cabot Corporation) with 1000 ml of water, 450 g of sodium hypochlorite (effective chlorine concentration: 12%) was added dropwise, and 100 to 105 ° C. For 8 hours. To this solution, 100 g of sodium hypochlorite (effective chlorine concentration 12%) was further added and dispersed for 3 hours with a horizontal disperser. The resulting slurry was diluted 10 times with water, pH was adjusted with lithium hydroxide, desalted and concentrated with an ultrafiltration membrane to a conductivity of 0.2 mS / cm, and a carbon black dispersion having a pigment concentration of 15% It was. Coarse particles were removed by centrifugation and further filtered through a 1 micron nylon filter to obtain a carbon black dispersion 2. The total content of Fe, Ca and Si was 100 ppm or less as measured by ICP. The chlorine ion concentration was also set to 10 ppm or less. The average particle size (D50%) measured by Microtrac UPA was 95 nm.

Ink a
An ink composition having the following formulation was prepared and adjusted with a 10% aqueous solution of lithium hydroxide so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and obtained the ink composition.
Colorant Example 4 Carbon black dispersion 1 treated with diazo compound 1 8.0 wt% (as solids)
1,4-butanediol 22.5% by weight
Glycerin 7.5% by weight
N-methyl-2-pyrrolidone 2.0% by weight
Surfactant of specific example (II-2) 2.0% by weight
2,2,4-Trimethyl-1,3-pentanediol 2.0% by weight
Proxel LV (preservative) 0.2% by weight
Remaining amount of ion-exchanged water

Ink b
An ink composition was prepared in the same manner as ink a except that the following composition was used, and the pH was adjusted to 9 with lithium hydroxide.
Colorant Example 1 Phthalocyanine pigment-containing polymer fine particle dispersion 15.0% by weight (as solids)
1,5-pentanediol 15.0% by weight
Glycerin 15.0% by weight
N-hydroxyethyl-2-pyrrolidone 2.0% by weight
Surfactant of specific example (II-3) 2.0% by weight
2-ethyl-1,3-hexanediol 2.0% by weight
Proxel LV (preservative) 0.2% by weight
Remaining amount of ion-exchanged water

Ink c
An ink composition was prepared in the same manner as ink a except that the following composition was used, and the pH was adjusted to 9 with lithium hydroxide.
Colorant Example 2 Dimethylquinacridone pigment-containing polymer fine particle dispersion 15.0% by weight (as solid content)
1,6-hexanediol 22.5% by weight
Glycerin 7.5% by weight
2-pyrrolidone 3.0% by weight
Surfactant of specific example (II-4) 2.0% by weight
2,2,4-Trimethyl-1,3-pentanediol 2.0% by weight
Proxel LV (preservative) 0.2% by weight
Remaining amount of ion-exchanged water

Ink d
An ink composition was prepared in the same manner as ink a except that the following composition was used, and the pH was adjusted to 9 with sodium hydroxide.
Colorant Example 3 Monoazo yellow pigment-containing polymer fine particle dispersion 15.0% by weight (as solids)
2-methyl-2,4-pentanediol 22.5% by weight
Glycerin 7.5% by weight
N-methyl-2-pyrrolidone 5.0% by weight
Surfactant represented by the general formula (III) (R = n-hexyl group, k = 5) 2.0% by weight
2-ethyl-1,3-hexanediol 2.0% by weight
Proxel LV (preservative) 0.2% by weight
Remaining amount of ion-exchanged water

  Table 2 below shows the concentrations of the color material solids (pigments and emulsions), the wetting agent concentration, and the ink viscosity of the ink compositions of inks a to d.

Description of recording medium Recording medium 1-1 (OHP sheet)
A coating solution was prepared by mixing 100 g of alumina sol having a solid content of 18% by weight synthesized by hydrolysis and peptization of aluminum alkoxide and 32 g of 6.2% by weight aqueous solution of polyvinyl alcohol. This coating solution is coated on a polyethylene terephthalate film (thickness 100 μm, white) using a bar coater so that the coating amount after drying is 20 g / m ² and dried to form a pseudo boehmite layer. did. Further, a solid content of 5% by weight (copolymer / SiO2) composed of a siligasol having a primary particle diameter of 10 to 20 nm and a polyvinyl alcohol copolymer having a silanol group (trade name R-polymer R-1130, manufactured by Kuraray Co., Ltd.). ₂ = 0.3) OHP sheet obtained by applying and drying the silica sol coating solution so that the thickness of the silica gel layer after drying is 1 μm, and heat-treating at 140 ° C.

Recording medium 1-2 (OHP sheet)
A coating solution was prepared by mixing 100 g of alumina sol having a solid content of 18% by weight synthesized by hydrolysis and peptization of aluminum alkoxide and 32 g of 6.2% by weight aqueous solution of polyvinyl alcohol. This coating solution is applied onto a polyethylene terephthalate film (thickness 100 μm, white) using a bar coater so that the coating amount after drying is 16 g / m ² and dried to form a pseudo boehmite layer. did. Further, a solid content of 5% by weight (copolymer / SiO2) composed of a siligasol having a primary particle diameter of 10 to 20 nm and a polyvinyl alcohol copolymer having a silanol group (trade name R-polymer R-1130, manufactured by Kuraray Co., Ltd.). ₂ = 0.3) OHP sheet obtained by applying and drying the silica sol coating solution so that the thickness of the silica gel layer after drying is 1 μm, and heat-treating at 140 ° C.

Recording medium 1-3 (OHP sheet)
A coating solution was prepared by mixing 100 g of alumina sol having a solid content of 18% by weight synthesized by hydrolysis and peptization of aluminum alkoxide and 32 g of 6.2% by weight aqueous solution of polyvinyl alcohol. This coating solution is applied onto a polyethylene terephthalate film (thickness 100 μm, white) using a bar coater so that the coating amount after drying is 30 g / m ² and dried to form a pseudo boehmite layer. did. Further, a solid content of 5% by weight (copolymer / SiO2) composed of a siligasol having a primary particle diameter of 10 to 20 nm and a polyvinyl alcohol copolymer having a silanol group (trade name R-polymer R-1130, manufactured by Kuraray Co., Ltd.). ₂ = 0.3) OHP sheet obtained by applying and drying the silica sol coating solution so that the thickness of the silica gel layer after drying is 1 μm, and heat-treating at 140 ° C.

Recording medium 2-1 (glossy paper)
Polyethylene resin coating layer (containing surface treated anatase-type titanium dioxide pigment and zinc stearate on the front side) is melt extruded on both sides of a base paper with a basis weight of 83g / m ² and smoothness of 200 seconds. The resin surface on the front side of the resin-coated paper support for an inkjet recording sheet provided by coating is subjected to corona discharge treatment, and 16.6 wt% of 5% aqueous solution of polyvinyl alcohol (saponification degree 98.5 mol%, average polymerization degree 1700). %, 1% by weight of a 2% mixture of methanol and water of sulfosuccinic acid-2-ethylhexyl ester salt, and 4.5% by weight of dry colloidal silica (based on acicular colloidal silica, silica ( Acicular colloidal silica cation-modified with about 6.2% by weight of hydrous aluminum oxide in terms of Al ₂ O ₃ relative to SiO ₂ Inkjet glossy paper obtained by coating and drying an ink-jet receiving layer coating solution comprising pure water of Nissan Chemical Co., Ltd.) and remaining weight% with a coater so that the dry weight is 28 g / m ² .

Recording medium 2-2 (glossy paper)
Polyethylene resin coating layer (containing surface treated anatase-type titanium dioxide pigment and zinc stearate on the front side) is melt extruded on both sides of a base paper with a basis weight of 83g / m ² and smoothness of 200 seconds. The resin surface on the front side of the resin-coated paper support for an inkjet recording sheet provided by coating is subjected to corona discharge treatment, and 16.6 wt% of 5% aqueous solution of polyvinyl alcohol (saponification degree 98.5 mol%, average polymerization degree 1700). %, 1% by weight of a 2% mixture of methanol and water of sulfosuccinic acid-2-ethylhexyl ester salt, and 4.5% by weight of dry colloidal silica (based on acicular colloidal silica, silica ( Acicular colloidal silica cation-modified with about 6.2% by weight of hydrous aluminum oxide in terms of Al ₂ O ₃ relative to SiO ₂ An inkjet glossy paper obtained by coating and drying an inkjet receptive layer coating solution comprising pure water of Nissan Chemical Co., Ltd.) and remaining weight% with a coater so as to have a dry weight of 20 g / m ² .

Recording medium 2-3 (glossy paper)
Polyethylene resin coating layer (containing surface treated anatase-type titanium dioxide pigment and zinc stearate on the front side) is melt extruded on both sides of a base paper with a basis weight of 83g / m ² and smoothness of 200 seconds. The resin surface on the front side of the resin-coated paper support for an inkjet recording sheet provided by coating is subjected to corona discharge treatment, and 16.6 wt% of 5% aqueous solution of polyvinyl alcohol (saponification degree 98.5 mol%, average polymerization degree 1700). %, 1% by weight of a 2% mixture of methanol and water of sulfosuccinic acid-2-ethylhexyl ester salt, and 4.5% by weight of dry colloidal silica (based on acicular colloidal silica, silica ( Acicular colloidal silica cation-modified with about 6.2% by weight of hydrous aluminum oxide in terms of Al ₂ O ₃ relative to SiO ₂ Inkjet glossy paper obtained by coating and drying an ink-jet receiving layer coating solution consisting of Nissan Chemical Co., Ltd.) and pure water of the remaining weight% with a coater to a dry weight of 10 g / m ² .

Recording medium 3-1 (matte coated paper)
“Image matte finish (super fine grade)” (inkjet paper; manufactured by Fuji Photo Film Co., Ltd.).

Recording medium 3-2 (matte coated paper)
"Superfine paper" (inkjet paper; manufactured by Seiko Epson Corporation).

をドット倍率とした。結果を表３に示す。 Next, the following tests were performed on the recording medium and the inks a to d using the ink set A composed of cyan, magenta, yellow, and black shown in Table 2.
Ink jet printer with 384 piezo-type nozzles arranged at 300 dpi intervals, one for each of C, M, Y, and K, changing head drive voltage, frequency, pulse width, etc. Ink droplets were discharged and printing was performed on each of the recording media. Printing pattern is C, M, Y single-color solid pattern, B, G, R two-color solid pattern, K solid pattern, C, M, Y, K, B, G, R character patterns, each color The one having a dot pattern was used.
A multi-pass recording method in which the head is divided into eight in units of 48 nozzles, paper is fed in correspondence with the divided one block, and the same area of the recording medium is scanned eight times by the ink jet head to record at a resolution of 600 dpi. A multi-pass recording method was performed in which the paper was divided into 16 units in units of 24 nozzles, paper was fed corresponding to the divided one block, and the same area of the recording medium was scanned 16 times by the inkjet head and recorded at a resolution of 1200 dpi. .
After printing and drying, the dot diameter and shape factor were measured, and banding unevenness, character quality, and solid portion uniformity were evaluated.

Is the dot magnification. The results are shown in Table 3.

(Criteria)
Banding unevenness A: Almost unknown.
○: Slight unevenness is observed.
X: Uneven banding is clearly noticeable.
Character quality Character bleeding (feathering) was judged visually.
A: Excellent (no bleeding is observed).
○: Good.
Δ: Slightly inferior
X: Inferior.
Solid part uniformity The smoothness of the solid part was visually determined.
A: Excellent (smooth and not rough)
○: Good.
Δ: Slightly inferior
X: Inferior.

1 is a schematic front view showing a configuration example of a serial type ink jet recording apparatus equipped with an ink cartridge containing a recording liquid of the present invention. FIG. 3 is an external perspective view of the ink cartridge before being loaded into the recording apparatus of the present invention. It is a front sectional view of the ink cartridge of the present invention. 1 is an external perspective view of a recording unit integrated with a recording head of the present invention. It is an external appearance perspective view of another specific example of the ink cartridge of this invention. It is the schematic of another specific example of the inkjet recording device carrying the ink cartridge which accommodated the recording liquid of this invention. 1 is a perspective view schematically showing a configuration of a serial type ink jet printer which is an embodiment of an image forming method and an image forming apparatus according to the present invention. It is a figure which shows the multipass scanning method.

Explanation of symbols

(Figs. 1-4)
DESCRIPTION OF SYMBOLS 1 Side plate 2 Side plate 3 Main support guide rod 4 Sub support guide rod 5 Carriage unit 6 Head 6a Discharge surface (nozzle surface)
7 ink cartridge 7y yellow ink cartridge 7m magenta ink cartridge 7c cyan ink cartridge 7k black ink cartridge 8 main scanning motor 9 drive pulley (drive timing pulley)
10 Driven pulley (idler pulley)
DESCRIPTION OF SYMBOLS 11 Timing belt 12 Bottom plate 13 Sub frame 14 Sub frame 15 Conveyance roller 16 Paper 17 Sub scanning motor 18 Gear 19 Gear 21 Reliability maintenance recovery mechanism (subsystem)
22 Cap means 23 Holder 24 Link member 25 Engagement part 26 Suction tube 27 Suction pump 28 Wiping means (wiper blade)
29 Blade arm 30 Recording unit 31 Electrode 32 Nozzle 41 Cartridge body (ink tank)
42 Ink Absorber 43 Case 44 Upper Cover Member 45 Ink Supply Port 46 Seal Ring 47 Atmospheric Release Port 48 Groove 50 Cap Member 51 Ink Supply Port 52 Reinforcing Rising Portion 53 Hooking Portion 55 Film-like Seal Member 71 Cartridge Insertion Guide 81 Handle 81a Sliding Stop 82 Recess A Space (Fig. 5)
501 Ink cartridge 502 Ink bag (ink storage means)
503 Case 511 Case component member 512 Case component member 513 Case component member 525 Supply port 541 Recess 542 Hook portion 544 Guide portion 545 Guide portion 553 Open portion 564 Color identification means 582 Screw member (FIG. 6)
DESCRIPTION OF SYMBOLS 101 Inkjet recording apparatus 102 Paper feed tray 103 Paper discharge tray 111 Upper cover 112 Front cover front surface 131 Guide rod 132 Stay 133 Carriage 134 Recording head 135 Ink sub tank 141 Paper stacking section (pressure plate)
142 Paper 143 Feed roller 144 Separation pad 145 Guide 151 Transport belt 152 Counter roller 153 Transport guide 154 Press member 155 Tip pressure roller 156 Charging roller 157 Transport roller 158 Tension roller 161 Guide member 171 Separation claw 172 Discharge roller 173 Discharge Roller 181 Screen paper feed unit 182 Manual paper feed unit (Fig. 7)
711 (Serial type) Inkjet printer (image forming device)
712 Print head 713 Rail 715 Steel strip 716 Paper feed mechanism 717 Print head drive mechanism 719 Controller 7a Paper feed direction 7b Recording medium 7P Reciprocating motion direction

Claims (9)

An ink jet recording method for forming an image by ejecting ink from an ink jet head to a recording medium, wherein the ink is a colorant, a wetting agent, a polyol or glycol ether having 8 to 11 carbon atoms, an anion or a nonionic type. Including a surfactant and a water-soluble organic solvent, the content of the colorant is 8% by weight or more, the content of the wetting agent is 10 to 50% by weight , and the viscosity at 25 ° C. is 8 mPa · sec or more . It is a certain aqueous ink, and the colorant is a pigment or a polymer emulsion in which polymer fine particles contain a water-insoluble or hardly soluble colorant, and the wetting agent is glycerin or glycerin and 1,3-butanediol. , Triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol, diethyl It is a high viscosity wetting agent mixed with at least one selected from lenglycol, dipropylene glycol, trimethylolpropane, trimethylolethane, 1,4-butanediol, and 2-methyl-2,4-pentanediol. The recording medium is a recording medium in which an ink receiving layer is provided on a support, and the resolution of a color image formed on the recording medium is 600 dpi or more and 1200 dpi or less, and is provided on the recording medium. The dot diameter Dd (μm) after the ink droplet is fixed is

(However, Dp (μm) is the distance between the centers of adjacent pixels, and if the resolution (printing density) is R (dpi), then Dp = 2.54 × 10 ⁴ / R) and the dot An ink jet recording method having a shape factor of 1.15 or more and 1.50 or less.   The color ink jet recording method according to claim 1, wherein the ink is a multi-color ink including at least three colors of yellow, cyan, and magenta. The ink-jet head, a color ink jet recording method according to claim 1 or 2, characterized in that it comprises a thermal energy generator for generating thermal energy for discharging ink. The ink-jet head, ink jet recording method according to claim 1 or 2, characterized by performing ink discharge by applying mechanical energy to the ink. The inkjet recording method according to any one of claims 1 to 4, wherein the recording medium is an OHP sheet. An image corresponding to image data by ejecting ink onto a recording medium while scanning an inkjet head having a plurality of ejection units for ejecting ink relative to the recording medium, and applying a single color dot to one pixel. Is formed on the recording medium, and the ink includes a colorant, a wetting agent, a polyol or glycol ether having 8 to 11 carbon atoms, an anionic or nonionic surfactant, and a water-soluble organic solvent. A water-based ink in which the content of the colorant is 8% by weight or more, the content of the wetting agent is 10 to 50% by weight , and the viscosity at 25 ° C. is 8 mPa · sec or more. A polymer emulsion in which a pigment or a polymer fine particle contains a water-insoluble or hardly soluble colorant, and the wetting agent is glycerin or Lysine and 1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, trimethylolethane, 1,4-butanediol And a high-viscosity wetting agent in which at least one selected from 2-methyl-2,4-pentanediol is mixed, and the recording medium is a recording medium provided with an ink receiving layer on a support. The resolution of the image formed on the recording medium is 600 dpi or more and 1200 dpi or less, and the dot diameter Dd (μm) after the ink dots (droplets) applied on the recording medium are fixed,

(However, Dp (μm) is the distance between the centers of adjacent pixels, and if the resolution (printing density) is R (dpi), then Dp = 2.54 × 10 ⁴ / R) and the dot An ink jet recording apparatus comprising: a drive unit that causes the ink jet head to perform recording based on the image data so that a shape factor is 1.15 or more and 1.50 or less. The inkjet recording apparatus according to claim 6 , wherein the inkjet head includes a thermal energy generator that generates thermal energy for ejecting ink. The ink-jet head, an ink jet recording apparatus according to claim 6 or 7, characterized in that ejects ink by applying mechanical energy to the ink. Wherein the conveyance unit for conveying the recording medium, ink jet recording apparatus according to claim 6 to 8, characterized in that it comprises a conveyor belt for conveying the recording medium by electrostatic adsorption.

Images