JP3093323B2 - Ink jet recording head and ink jet recording apparatus using the head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head and an ink jet recording apparatus.

[0002] In particular, the present invention relates to a recording head and a recording apparatus in which ink paths are improved to improve durability and enable high-speed recording.

(Description of Related Art) A typical example of an ink jet recording head is to generate heat by giving a drive signal to an electrothermal transducer, thereby heating ink around a heat generating portion (hereinafter also referred to as a heater) to foam. Is applied to the ink, and the ink is ejected by the pressure generated at that time.An electrothermal converter, which is a heat energy generator that generates heat energy used for ejecting the ink, and an ink. An ink path (hereinafter also referred to as a nozzle) communicating with a discharge port for discharging (hereinafter also referred to as an orifice)
And

Conventionally, as shown in a sectional view of FIG. 10, for example, as shown in a sectional view of FIG. 10, except for a throttle portion on an ejection port side for ejecting ink, a nozzle rear end (supply port) on a common ink chamber side is formed. A typical configuration has a straight shape over the entire length up to) and achieves smooth outflow of ink.

[0005]

However, in the ink path having such a structure, the pressure generated by energization of the heater and the bubbling accompanying the heating is directly transmitted not only to the discharge port but also to the upstream of the ink flow. Back wave).

[0006] Since this back wave impedes the flow of ink from upstream during refilling, there is a problem to be solved in that it takes time for refilling and it is difficult to perform high-speed ink ejection.

In a head having a common liquid chamber upstream of the ink path, the back wave also affects other ink paths (crosstalk) via the common liquid chamber, thereby making the ink ejection state unstable. There was a problem to be solved.

Further, in the ink path having the above-described structure, the heater is greatly damaged by cavitation generated at the time of defoaming, and the durability is, for example, about 1 × 10 ⁸ pulses / nozzle.

To solve these problems, Japanese Patent Application Laid-Open No. 55-1001
No. 69, JP-A-61-40160, USP
Japanese Patent No. 4,882,595 discloses an example in which a fluid resistance element is provided upstream of a discharge heater in order to reduce back waves, improve responsiveness efficiency, and reduce meniscus vibration crosstalk. However, there has been a problem to be solved that damage to the heater (cavitation) and the like when the foamed foam disappears is not taken into account, and that a sufficient heater life has not been obtained. Japanese Patent Application Laid-Open No. Sho 59-138460, filed by the applicant of the present invention, discloses a type in which a discharge port is provided on a surface opposite to a surface on which a heater is arranged, and an ink discharge direction and a refill direction of the ink form a right angle. An example was shown in which the recording head described above deformed the flow path wall near the heater to move the position of the bubble at the time of defoaming, thereby preventing cavitation to the heater.

However, in JP-A-59-138460, since the impact force itself at the time of defoaming is not reduced by dividing the foamed foam or the like, the ink path wall or electrode near the heater is damaged. Was given. In particular, in a head in which the ejection port, the heater, and the ink supply port from the common liquid chamber are arranged substantially in a straight line, the flow of ink onto the heater at the time of defoaming is caused by the ink supply port side (upstream side). ) As well as from the discharge port side due to meniscus receding, there remains a problem to be solved that it is difficult to sufficiently shift the defoaming position from above the heater.

[0011]

SUMMARY OF THE INVENTION The above-mentioned problems are caused by a discharge port for discharging ink, an ink path provided corresponding to the discharge port, and the generation of bubbles by heating the ink in the ink path. Heat energy generating means for generating heat energy for causing the ink path to be upstream by the heat energy generating means, at a position where a part of the bubble passes when the bubble is maximally foamed. A fluid resistance portion for locally minimizing the cross-sectional area of the ink path, and a ratio of the cross-sectional area of the ink path to the minimum cross-sectional area of the ink path in the fluid resistance section is 27% ≦ H2 ≦ 55% ( H2: the minimum cross-sectional area of the ink path / the cross-sectional area of the ink path in the fluid resistance section), wherein the bubble is divided by the fluid resistance section. It is determined.

According to the recording head and the recording apparatus of the present invention which the present inventors have intensively studied for the above-mentioned problems and have achieved,
The ink path is provided with a fluid resistance part (hereinafter also referred to as a fluid resistance element) at a position where a part of the foam (hereinafter also referred to as a bubble) formed by heating of the heater passes and is divided, so that the ink path after the foaming is formed. Can suppress the receding meniscus and reduce the back wave, so that the ink refill time can be shortened, and the influence of the back wave crosstalk on the ink discharge of other nozzles can be further reduced. . Further, since the foamed foam is cut, the energy itself at the time of defoaming can be reduced, cavitation to a heater, an electrode ink path, and the like can be reduced, and durability performance can be improved.

[0013]

Embodiments of the present invention for improving refill characteristics and durability will be described in detail with reference to the drawings.

FIG. 1 is a perspective view schematically showing an example of an ink jet recording head provided with a fluid resistance portion having a locally reduced cross-sectional area in the direction of the upstream side (common liquid chamber side) of the heater according to the present invention. is there.

In FIG. 1, reference numeral 11 denotes a heat-generating portion (discharge heater) of an electrothermal converter as a heat energy generator for generating heat by energization (application of a drive signal) to cause a bubbling phenomenon in the ink to discharge the ink. ). 12
Is a substrate, and the heat generating portion 11 is formed on the substrate through a manufacturing process similar to a semiconductor manufacturing process. Reference numeral 13 denotes an ink discharge port, which is shown with the same cross-sectional area as that of the flow path for simplification. Reference numeral 14 denotes an ink path communicating with the ejection port 13. Reference numeral 18 provided in the ink path 14
Is a fluid resistance part for locally reducing the cross-sectional area of the nozzle. Reference numeral 15 denotes an ink path forming member for forming the ejection port 13 and the ink path 14, and 16 denotes a top plate. Reference numeral 17 denotes an ink chamber commonly communicating with each ink path 14.

FIG. 2 is a schematic top view showing the function of the ink path shown in FIG.

In FIG. 1, reference numeral 1 denotes an ink path (nozzle);
Is a discharge port, 3 is a discharge heater, 4 is a fluid (concentration) resistance element as a fluid resistance portion, 6 is a bubble, 7 is a separated bubble, and 8 is a discharge ink.

FIG. 3 is a schematic view showing the nozzle of FIG. 2 from the side, and the same parts are denoted by the same reference numerals. Reference numeral 5 indicates a common ink chamber.

In FIG. 2, the thermal energy generated by the heater 3 heats the ink near the heater and causes a bubbling phenomenon. Since the cross-sectional areas of the ink paths near the heater are almost the same and are straight, the foamed bubbles grow in the direction of the common ink chamber downstream of the nozzle 1 and on the upstream side.
The pressure acting on the front of the nozzle 1 out of the pressure generated by the bubble growth causes the ink to be ejected from the ejection port 2.

On the other hand, the pressure in the upstream direction of the nozzle 1 receives a reaction force by the fluid resistance element 4 as a fluid resistance part, and the bubbles pass through the fluid resistance element 4 and are separated behind the concentrated resistance element 4. Remains. The separated bubble disappears when the bubble is defoamed after the bubble is maximally foamed.

In a nozzle having no fluid resistance element as shown in FIG. 10, bubbles grow to a maximum of 310 μm. However, as shown in FIG. 2 according to this embodiment, for example, a distance T from the rear end of the heater is 30 μm. Nozzle cross-sectional area 10
By providing the constriction resistance element 4 such that the cross-sectional area of 327Myuemu ² which corresponds to 30% of the 90 [mu] m ^2, the bubble separation by constriction resistance element portion during the bubble growth, is divided, maximum expansion length of bubbles on the heater is 230μm becomes The damage to the heater due to cavitation at the time of defoaming was reduced, and the durability performance was improved by about 30% as compared with the nozzle as shown in FIG.

In the nozzle provided with the fluid resistance element as in this embodiment, the fluid resistance (rear impedance) of the ink path from the center of the heater toward the common ink chamber is higher than that of the fluid from the common ink chamber to the center of the heater. It becomes higher than the resistance (forward impedance).

Table 1 shows the liquid resistance obtained by simulation for a nozzle having a fluid resistance element of the type shown in this embodiment and a straight nozzle not having the fluid resistance element.

[0024]

[Table 1]

As shown in Table 1, the nozzle having the fluid resistance element has a high rear impedance, so that the flow rate of the ink to the common ink chamber side during foaming and when the foam grows is reduced, and unnecessary. Suppress backflow of ink. For this reason, the amount of ink required for ink refilling (refilling) is reduced, the refilling characteristics (response frequency) are also improved, and the kinetic energy of the ink moving in the bubble contraction direction immediately before the bubble disappears is reduced. This kinetic energy is also considered to correlate with the cavitation intensity. In Table 4, since the simulation was performed with the nozzle length kept constant, the position of the heater was moved slightly forward by providing the fluid resistance element, so that the forward impedance became a value slightly reduced. I have.

It is considered that the kinetic energy immediately before the defoaming of the ink, which correlates with the cavitation intensity, is generated by converting the potential energy of the system when the bubble volume is the maximum to the kinetic energy. Therefore, as in the present embodiment, by providing the fluid resistive element at a position where a part of the bubble passes when the bubble is maximally foamed, dividing the bubble and reducing the volume of the bubble on the heater, the kinetic energy of the ink immediately before defoaming can be reduced. The cavitation can be effectively reduced. The kinetic energy of the ink in the nozzle, which increases from the time when the bubble volume reaches the maximum to the time when the bubble disappears, can be taken as a physical quantity correlated with the cavitation intensity. The results obtained by simulating the amount of increase in the kinetic energy in the nozzle and the straight type according to the present embodiment are shown.

[0027]

[Table 2]

As shown in Table 2, in this embodiment in which the fluid resistance element is provided at the position where the foamed foam is divided, the nozzle having no fluid resistance element or the fluid resistance element is provided at the position where the foam is not divided. It can be seen that the amount of increase in kinetic energy is smaller than that of the nozzle, that is, the cavitation intensity is reduced.

In the nozzle of this embodiment, the volume of the bubble on the heater is reduced by the fragmentation of the bubble, and the ink moves toward the defoaming point at the time of refilling. Kinetic energy is not concentrated because it has a defoaming point, and some of the divided bubbles are defoamed by being defoamed upstream of the fluid resistance element, that is, at a position other than on the heater. Damage to the heater, electrodes, etc. due to the cavitation was significantly reduced.

Further, by providing the fluid resistance element at a position where a part of the bubble passes at the time of maximum foaming, the nozzle itself can be designed to be short, and the fluid resistance of the nozzle at the time of ink refill can be reduced. The frequency is further improved. Table 3 shows the response frequencies of the nozzle of the present invention in which the lumped resistance element is provided at the position where the bubble passes when the bubble is maximally bubbled and the nozzle of the comparative example in which the lumped resistance element is provided at a position far from the heater through which the bubble does not pass.

[0031]

[Table 3]

As described above, the response frequency can be further improved by the present invention.

FIG. 4 shows another embodiment in which the fluid resistance element 4 is provided in a columnar shape at the center of the nozzle 1 and the cross-sectional area of the ink path of the fluid resistance element section is set to 30% of the cross-sectional area of the nozzle.
FIG. 5 shows this cross-sectional view. At the time of bubble growth, some of the bubbles pass through and are separated from both sides of the fluid resistance element 4. At this time, the maximum foaming length on the heater was 220 μm, and damage to the heater and electrodes due to cavitation at the time of defoaming was reduced as in the case of the previous embodiment, and the durability performance, refill characteristics, etc. were improved.

FIGS. 6, 7 and 8 show still another embodiment of the present invention, in which a fluid resistance element is provided at a lower portion, an upper portion, and an upper and lower portion of an ink path, respectively. FIG. FIG. 9 is a schematic top sectional view of these. Also in these embodiments, as in the embodiment shown in FIGS. 1 to 5, bubbles are separated at the fluid resistance element portion, the maximum foaming length becomes approximately 220 μm, and damage to the heater due to cavitation at the time of defoaming is reduced. As a result, the durability performance was improved and the refill characteristics were improved. The relationship between the position of the fluid resistance element and the minimum cross-sectional area of the ink path of the fluid resistance element portion is determined by various conditions.
It is as follows. The head and its driving conditions are as follows: nozzle length 340 μm, nozzle cross-sectional area 1090 μm 2 (almost uniform), heater size 28 × 133 (μm), discharge port
The distance between the heaters was 120 μm, the pulse width was 3 μs, and the driving voltage was 28 V. As a result, the durability performance was L3 × 108 pulses / nozzle, and a 30% life improvement was observed.

[0035]

[Table 4]

In the case where the fluid resistance element shown in the embodiment of FIG. 1 to FIG. 3 is provided for the nozzles A and B described below, the position of the fluid resistance element and the bubbles in the fluid resistance element portion Table 5 shows the relationship between the minimum cross-sectional area of the ink path and the ink path.

A. Nozzle length 320μ, nozzle cross-sectional area (other than fluid resistance element part) 1750μm ² (35 × 50), heater size 28 × 133 (μm), distance between discharge port and heater 120μ, discharge port cross-section area 1155μm ² (35 ×
33). B. Nozzle length 320μ, nozzle cross-sectional area (other than fluid resistance element) 1150μm ² (23 × 50), heater size 28μ × 133 (μm), distance between discharge port and heater 12
0 μ, discharge port sectional area 575 μm ² (23 × 25).

Both A and B are provided with a fluid resistance element as shown by the cross-sectional shape in FIG. 2 for improving refill characteristics and suppressing back waves, and the length of the fluid resistance element in the ink path direction is set to 20 μm. . The ink path minimum sectional area (region) of the fluid resistance element has an acute angle (90 °> θ).

[0039]

[Table 5]

According to the above configuration, the durability was further improved as compared with the experimental example.

The size of the foam generated by heating the heater depends on the size of the discharge heater.

Therefore, in order to efficiently separate the foamed foam, these must also be considered.

In particular, when a fluid resistance element for regulating the width direction of the ink path is used as shown in FIGS. 1 to 3, the width of the discharge heater and the width of the flow path grow in the width direction of the ink path. Since it greatly affects the size of the foam, it is desirable to determine the width of the fluid resistance element portion at the minimum flow path width position (minimum width position) based on these conditions.

When the width of the fluid resistance element portion at the minimum width position is extremely narrower than the discharge heater width, it is difficult to efficiently guide bubbles to the minimum width position. On the other hand, when the width is extremely wide, the turbulence generated near the minimum width position is reduced, so that it is difficult to break the bubbles. Therefore, the ratio of the preferable discharge heater to the minimum width position width of the fluid resistance element (minimum width position width / heater width =
H1) is about 60% ≦ H1 ≦ 95%, preferably 68% ≦ H1 ≦ 87%, more preferably 74% ≦ H1 ≦
82% is sufficient.

The relationship between the width (cross-sectional area) of the ink path at the position where the fluid resistance element is not provided and the minimum cross-sectional area of the ink path at the position where the fluid resistance element is provided is represented by the minimum breakage of the ink path. If the area is too large for the cross-sectional area of the ink path,
It becomes difficult to efficiently divide the bubbles, and the effect of suppressing the back wave is reduced. On the other hand, if it is too narrow, it will be difficult to guide the bubbles to the position of the fluid resistance element, and the refill time will be long. Therefore, the ratio of the cross-sectional area of the ink path to the minimum cross-sectional area of the ink path in the fluid resistance element portion is 27% ≦
H2 ≦ 55% (H2: the minimum cross-sectional area of the ink path in the fluid resistance element portion / the cross-sectional area of the ink path) is sufficient, and preferably 30% ≦ H2 ≦ 43%.

As shown in FIG. 4, in the case where the fluid resistance element is provided at the center of the ink path, the flow path of the ink is divided. Therefore, H1 should preferably be about 70% ≦ H1 ≦ 90%. May be 75% ≦ H1 ≦ 87%.

The above-mentioned width may be considered as the cross-sectional area when the shape of the cross section of the ink path is not rectangular or square.

It is preferable that the distance between the heater end and the minimum width position of the fluid resistance element portion is provided up to about 80 μm upstream from the heater end, but it is desirable to set the distance to 55 μm since the separation of bubbles becomes difficult as the distance increases. Hereinafter, it is more preferable that the thickness be 42 μm or less. The lower limit may be at the end of the heater, but it is preferably 5 μm or more, more preferably 25 μm or more, since it is easier to break up bubbles to some extent upstream. FIG.
In the configuration as shown in the above, when the fluid resistance element is in contact with the heater, the growth of bubbles in the upstream direction is strongly hindered, so that the above-described distance is about 10 μm in order to efficiently induce and divide the bubbles. You should open it.

It is preferable that the separation of the bubbles is performed during the growth of the bubbles from the viewpoint of suppressing the growth of the bubbles (reducing the amount of ink required at the time of refilling). Therefore, in terms of timing, it is desirable that the bubble be divided before the ejected ink is completely separated from the ink path.

The shape of the fluid resistance element is not limited to the above-described shape, and may be any shape that can efficiently separate foamed bubbles. It is preferable that the fluid resistance is large because the back wave can be reduced and the refill characteristics can be further improved. Needless to say, the fluid resistance element may be formed integrally with the ink path or may be formed separately. The fluid resistance element is not limited to the same material as the ink path, and may be any material that is insoluble in the ink and does not alter the quality of the ink. Examples of the material include glass, ceramics, plastic, metal, and these materials. Anything is fine.

In the above-described embodiment, it has been described that a particularly large effect can be obtained when the ink path from the common liquid chamber to the discharge port is substantially straight. By applying the configuration of the present invention to a nozzle that is not straight, a sufficient effect can be obtained.

FIG. 11 is a perspective view schematically showing an external configuration of an ink jet recording apparatus which carries a divided drive by mounting a recording head to which the present invention is applied. In FIG. 1, 1
Denotes an ink jet recording head (hereinafter, referred to as a recording head) for ejecting ink based on a predetermined recording signal and recording a desired image, and 2 scans in the recording row direction (main scanning direction) with the recording head 1 mounted thereon. It is a moving carriage. The carriage 2 is slidably supported by guide shafts 3 and 4, and reciprocates in the main scanning direction in conjunction with the timing belt 8. The timing belt 8 engaged with the burries 6 and 7 is driven by the carriage motor 5 via the burries 7.

The recording paper 9 is guided by a paper pan 10 and is conveyed by a paper feed roller (not shown) pressed by a pinch cola. This conveyance is performed using the paper feed motor 16 as a drive source. The transported recording paper 9 is tensioned by the discharge roller 13 and the spur 14 and is pressed against the heater 11 by the paper pressing plate 12 formed of an elastic member. It is conveyed while being performed. Head 1
The recording paper 9 to which the ink ejected by the ink is adhered is heated by the heater 11, and the adhered ink evaporates the solvent and is fixed on the recording paper 9. In addition. The heating and fixing by the heater 11 is not always necessary, and may be provided in the recording apparatus as appropriate according to the characteristics of the ink and the like.

Reference numeral 15 denotes a unit called a recovery system, which removes foreign substances and ink having increased viscosity attached to the discharge ports (not shown) of the recording head 1 to maintain the discharge characteristics in a normal state. belongs to.

Reference numeral 18a denotes a cap which constitutes a part of the recovery system unit 15, and serves to cap the discharge port of the ink jet recording head 1 to prevent clogging. An ink absorber 18 is provided inside the cap 18a.

On the recording area side of the recovery system unit 15, a cleaning blade 17 is provided for contacting the surface of the recording head 1 on which the discharge port is formed and cleaning foreign substances and ink droplets attached to the discharge port surface. ing.

The present invention provides an excellent effect particularly in a recording head and a recording apparatus of an ink jet recording system in which a flying liquid droplet is formed by utilizing thermal energy and recording is performed. .

The representative configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 474.
No. 0796, and the present invention is preferably performed using these basic principles. This recording method can be applied to both so-called on-demand type and continuous type.

The recording method will be briefly described. An electrothermal transducer arranged corresponding to a sheet or a liquid path holding a liquid (ink) and a liquid (ink) corresponding to recording information are used. Heat energy is generated by applying at least one drive signal for providing a rapid temperature rise that exceeds the nucleate boiling phenomenon and causes a film boiling phenomenon, thereby causing film boiling on the heat acting surface of the recording head. . As described above, since bubbles corresponding to the drive signal applied to the electrothermal converter from the liquid (ink) can be formed one-to-one, it is particularly effective for an on-demand type recording method. By discharging the liquid (ink) through the discharge port by the growth and contraction of the bubble,
Form at least one drop. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. Examples of the drive signal in the form of a pulse include U.S. Pat. Nos. 4,463,359 and 4,345.
No. 262 are suitable. If the conditions described in U.S. Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface described above are adopted, more excellent recording can be performed.

As the configuration of the recording head, a configuration combining a discharge port, a liquid flow path, and an electrothermal converter as disclosed in the above-mentioned respective specifications (linear liquid flow path or right-angled liquid flow path)
In addition, the present invention also includes those having a configuration in which a heat acting portion is arranged in a bent region as disclosed in US Pat. No. 4,558,333 and US Pat. No. 4,459,600.

In addition, Japanese Unexamined Patent Publication (Kokai) No. 123670/1984, which discloses a configuration in which a common slit is used as a discharge port of a gas heat converter for a plurality of electrothermal converters, or a pressure wave of heat energy. The present invention is also effective in a configuration based on JP-A-59-138461, which discloses a configuration in which the holes to be absorbed correspond to the discharge portions.

Further, as a recording head in which the present invention is effectively used, there is a full line type recording head having a length corresponding to the maximum width of a recording medium on which a recording apparatus can record. The full line head may be a full line configuration by combining a plurality of recording heads as disclosed in the above specification, or may be a single full line recording head formed integrally.

In addition, the print head is replaceable with a print head of a replaceable chip type, which can be electrically connected to the main body of the apparatus and can supply ink from the main body of the apparatus. The present invention is also effective when a cartridge-type recording head provided in a fixed manner is used.

It is preferable to add recovery means for the printhead, preliminary auxiliary means, and the like to the recording apparatus of the present invention because the recording apparatus of the present invention can be further stabilized. More specifically, preheating of the recording head by capping means, cleaning means, pressurizing or suction means, an electrothermal transducer or another heating element, or a combination thereof. Means and means for performing a preliminary ejection mode for performing ejection other than printing are also effective for performing stable printing.

Further, the recording mode of the recording apparatus is not limited to the mode for recording only the mainstream color such as black, and may be either a mode in which the recording head is integrally formed or a mode in which a plurality of recording heads are combined. However, the present invention is also very effective for an apparatus provided with at least one of multiple colors of different colors or full color by mixing colors.

In the embodiments of the present invention described above, the description is made using the liquid ink. However, in the present invention, the ink which is solid at room temperature or the ink which becomes soft at room temperature is used. Can be used. In general, in the above-described ink jet apparatus, the temperature of the ink itself is controlled within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. It is sufficient if the ink is in a liquid state.

In addition, an excessive temperature rise of the head and the ink due to thermal energy can be positively prevented by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent evaporation of the ink. Alternatively, an ink that solidifies in a standing state may be used. In any case, the ink is liquefied for the first time by the application of heat energy, such as one in which the ink is liquefied and ejected as an ink liquid by application of the heat energy according to the recording signal, or one which already starts to solidify when reaching the recording medium. The use of an ink having the following properties is also applicable to the present invention.

Such an ink is disclosed in JP-A-54-568.
No. 47 or Japanese Patent Application Laid-Open No. 60-71260, while being held as a liquid or solid substance in a concave portion or a through hole of a porous sheet, facing the electrothermal converter. It is good also as a form.

In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

Further, the form of the ink jet recording apparatus of the present invention is not limited to the one used as an image output terminal of information processing equipment such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function. It may take a form.

[0071]

As described above, in the present invention, the bubbles are separated by the improved ink path, the maximum foaming length is reduced, and the damage to the heater ink path and the like due to cavitation at the time of defoaming is reduced. Therefore, a great effect is achieved in improving the durability performance of the head, and the response frequency can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an ink jet recording head provided with a fluid resistance unit according to the present invention.

FIG. 2 is a schematic top cross-sectional view of an inkjet recording head according to another embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of an ink jet recording head according to another embodiment of the present invention.

FIG. 4 is a schematic top sectional view of an ink jet recording head according to another embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of an inkjet recording head according to another embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view of an inkjet recording head according to another embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view of an inkjet recording head according to another embodiment of the present invention.

FIG. 8 is a schematic cross-sectional view of an inkjet recording head according to another embodiment of the present invention.

FIG. 9 is an upper sectional view common to the ink jet recording heads of FIGS. 6 to 8;

FIG. 10 is a schematic top sectional view of an example of a conventional ink jet recording head.

FIG. 11 is a perspective view illustrating an example of a recording apparatus to which the inkjet recording head of the present invention can be applied.

[Explanation of symbols]

 Reference Signs List 1 nozzle 2 orifice 3 heater 4 concentrated resistance element 5 ink chamber 6 bubble 7 separated bubble 8 flying droplet

Claims (9)

(57) [Claims] A discharge port for discharging ink; an ink path provided corresponding to the discharge port; and heat energy generation for generating heat energy for heating ink in the ink path to generate bubbles. In the ink jet recording head, the ink path is localized by the thermal energy generating means, and the cross-sectional area of the ink path is localized at a position where a part of the bubble passes when the bubble is maximally foamed. And a ratio of the cross-sectional area of the ink path to the minimum cross-sectional area of the ink path in the fluid resistance section is 27% ≦ H2 ≦ 5.
5% (H2: minimum cross-sectional area of the ink path in the fluid resistance part / cross-sectional area of the ink path), wherein the bubble is divided by the fluid resistance part. 2. An ejection port for ejecting ink, an ink path provided corresponding to the ejection port, and thermal energy generation for generating heat energy for heating the ink in the ink path to generate bubbles. Means, wherein the ink path is upstream of the thermal energy generating means and faces two surfaces different from the surface on which the thermal energy generating means is disposed, at the time of the maximum foaming of the bubbles. A fluid resistance portion for locally minimizing the cross-sectional area of the ink path is provided at a position where a part of the bubble passes, and the difference between the cross-sectional area of the ink path and the minimum cross-sectional area of the ink path in the fluid resistance section. The ratio is 27% ≦ H2 ≦ 55% (H2: the minimum cross-sectional area of the ink path in the fluid resistance section / the cross-sectional area of the ink path), and it is characterized in that the bubble is divided by the fluid resistance section. An ink jet recording head according to. 3. The ink jet recording head according to claim 1, wherein the fluid resistance element has a shape in which a fluid resistance in an upstream direction is larger than a fluid portion in a downstream direction. 4. The ink jet recording head according to claim 1, wherein the ink path includes the fluid resistance portion at a center thereof. 5. The ink jet recording head according to claim 1, wherein the ink path includes the fluid resistance portion on a surface of the ink path on which the thermal energy generating unit is disposed. 6. The ink jet recording head according to claim 1, wherein the ink path includes the fluid resistance portion on a surface of the ink path opposite to a surface on which the thermal energy generating unit is arranged. 7. The ink jet recording head according to claim 2, wherein each of the opposed fluid resistance portions has an acute angle shape, and a tip portion of the acute angle shape has a minimum sectional area of an ink path. 8. A discharge port for discharging ink, an ink path provided corresponding to the discharge port, and thermal energy generation for generating heat energy for heating ink in the ink path to generate bubbles. Means, wherein the ink path locally minimizes the cross-sectional area of the ink path at a position upstream of the thermal energy generating means at a position where a part of the bubble passes when the bubble is maximally foamed. A ratio of the cross-sectional area of the ink path to the minimum cross-sectional area of the ink path in the fluid resistance section is 27% ≦ H2 ≦ 55% (H2:
(A minimum cross-sectional area of an ink path / a cross-sectional area of an ink path in a fluid resistance portion), comprising: an ink jet recording head that separates the bubbles by the fluid resistance portion; and transport means for transporting a recording medium. An ink jet recording apparatus characterized by the above-mentioned. 9. The ink jet recording apparatus according to claim 8, wherein the ink path includes a fluid resistance portion facing two surfaces different from the surface on which the thermal energy generating means is arranged.