JPH02258264A - Liquid jet recording device - Google Patents

Abstract

PURPOSE:To prevent the excess regression from a meniscus and thereby enable constantly stable ejection by connecting one or more auxiliary signals after a double-element signal which is entered to a thermal energy generating element for the generation of bubbles. CONSTITUTION:For example, a microsecond-wide pulse at 20V is applied as a drive signal. In addition, the second 3 microsecond-wide pulse at 20V is applied for a time t1 to prevent the excess regression from a meniscus. The second pulse application time t1 should be within a range of tp1<=tp2 as proved experi mentally (tp1 is a time when the first bubble grows to a maximum size, tp2 is a bubble disappearance time when only a drive signal is connected). that is, the time t1 is a time when the bubble has grown to a maximum size and remains shrunk). Furthermore, the time t1 should preferably be within a range of tp1<t1<=(2tp2+tp1)/3. Consequently, the bubble contracts quite smoothly with out shrinking excessively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid jet recording device, and more particularly to an inkjet printer.

The non-impact recording method with a rice plate has recently attracted attention because the noise generated during recording is so small that it can be ignored. Among them, high-speed recording is possible,
What about rR1? The so-called inkjet recording method is an extremely powerful recording method that allows recording without the need for special fixing processing during paper feeding.

Various methods have been proposed, some have been improved and commercialized, and efforts are still being made to put some into practical use.

Such an inkjet recording method involves jetting droplets of a recording liquid called ink.

Recording is performed by attaching the recording liquid to a recording member, and it is roughly divided into several methods depending on the method of generating recording liquid droplets and the control method for controlling the flight direction of the generated recording liquid droplets. Ru.

First, the first method is the one disclosed in US Pat. No. 3,060,429 (Tale type method), in which small droplets of recording liquid are generated by electrostatic attraction. Recording is performed by controlling the droplets with an electric field in accordance with a recording signal to selectively attach recording liquid droplets onto a recording member.

To explain this in more detail, an electric field is applied between the nozzle and the accelerating electrode to eject a negatively charged recording liquid droplet from the nozzle, and the ejected recording liquid droplet is converted into a recording signal. Accordingly, the droplet is caused to fly between x and y deflection electrodes configured to be electrically controllable, and the droplet is selectively deposited on the recording member by changing the intensity of the electric field to perform recording.

The second method is a method (Sweat method) disclosed in, for example, U.S. Pat. No. 3,596,275, U.S. Pat. Recording is performed on a recording member by generating droplets with a controlled amount of charge and flying the generated droplets between deflection electrodes to which a negative electric field is applied.

Specifically, the orifice (discharge port) of a nozzle, which is a part of the recording head to which the piezo vibrating element is attached.
A charged electrode configured to have a recording signal applied thereto is arranged at a predetermined distance in front of the piezo vibrating element, and an electric signal of a constant frequency is applied to the piezo vibrating element to mechanically vibrate the piezo vibrating element, A small droplet of recording liquid is ejected from the ejection port. At this time, discharge 81. A charge is electrostatically induced in the recording liquid droplet, and the droplet is charged with an 11F charge in accordance with the recording signal. A droplet of recording liquid with a controlled amount of charge is deflected by a constant electric field uniformly applied. When flying between i, the droplet is deflected according to the amount of charge added, so that only the droplet carrying the recording signal can adhere to the recording member.

The third method is, for example, US Pat. No. 3,416,153
1HIF (Hertz method).

In this method, an electric field is applied between a nozzle and a ring-shaped charged electrode, and small droplets of recording liquid are generated and atomized using a continuous vibration generation method to perform recording. That is, in this method, the atomization state of small droplets is controlled by modulating the electric field intensity applied between the nozzle and the charging electrode in accordance with the recording signal, and the M114 characteristic of the recorded image is produced.

The fourth method is the method disclosed in, for example, US Pat. No. 3,747,120 (Stapenzene method), and this method is fundamentally different in principle from the above three methods.

That is, in all three methods, the droplets of recording liquid ejected from the nozzle are electrically controlled while they are in flight, and the droplets carrying the recording signal are selectively attached to the recording member. In contrast, the Kome Stamme method records
Recording is performed by ejecting small droplets of recording liquid from an ejection port in response to a recording signal.

In other words, in the Stamms method, a piezo vibrating element attached to a recording head having an ejection port for ejecting recording liquid is used. Applying an electrical recording signal, converting the electrical recording signal into mechanical vibration of a piezoelectric vibrating element, and ejecting small droplets of recording liquid from the ejection port according to the mechanical vibration to attach them to the recording member. Recording is performed using .

These four conventional methods each have their own advantages, but there are also points that can be solved in the other method.

That is, in the first to third methods, the direct energy for generating droplets of the recording liquid is electrical energy, and the deflection control of the droplets is also electric field control.

Therefore, although the first method has a simple structure, it requires a high voltage to generate droplets, and it is difficult to use a multi-nozzle recording head, making it unsuitable for high-speed recording.

The second method allows the recording head to have multiple nozzles and is suitable for high-speed recording, but it has a complicated structure, and the electrical control of recording liquid droplets is sophisticated and difficult, and satellite dots are placed on the recording member. There are problems such as easy occurrence of.

The third method has the advantage that images with excellent gradation can be recorded by atomizing recording liquid droplets, but on the other hand, it is difficult to control the atomization state.

There are various problems such as fogging in the recorded image, difficulty in forming a recording head with multiple nozzles, and unsuitability for high-speed recording.

The fourth method has relatively many advantages compared to the first to third methods. That is, the configuration is simple, and in order to perform recording by ejecting the recording liquid from the ejection opening of the nozzle on-demand, the ejection is carried out as in the first to third methods. There is no need to collect droplets that are not needed for recording an image among the droplets, and there is no need to use a conductive recording liquid as in the first and second methods. It has great advantages such as a large degree of material freedom. On the other hand, it is difficult to make the recording head multi-nozzle because there are problems in processing the recording head, and it is extremely difficult to miniaturize the piezoelectric vibrating element having the desired resonance number. Since the recording liquid droplets are ejected into flight using the mechanical energy of the mechanical vibration of the piezo vibrating element, it has the disadvantage that it is not suitable for high-speed recording.

Furthermore, Japanese Patent Application Laid-Open No. 48-9622 (corresponding to the above-mentioned US Pat. No. 3,747,120) discloses, as a modification,
It is described that thermal energy is used instead of using mechanical vibration energy by means such as the piezo vibration element described above.

That is, the above-mentioned publication describes a so-called bubble jet liquid jet recording device that uses a heating coil that directly heats liquid as a pressure increasing means instead of a piezo vibrating element to generate steam that causes a pressure increase. There is.

However, in the above publication, the liquid ink in the bag-shaped ink chamber (liquid chamber), which has only one opening through which liquid ink can enter and exit, is directly heated and vaporized by energizing a heating coil as a pressure increasing means. However, when discharging liquid continuously and repeatedly, it is not clear how to heat it.
There is no suggestion whatsoever.In addition, the heating coil is located at the deepest part of the bag-shaped liquid chamber, far from the liquid ink supply path, so the head structure is complicated. In addition, for continuous repeated use at high speeds,
It is not suitable.

Moreover, based on the technical content described in the above publication.

After ejecting liquid, it is not possible to quickly prepare for the next liquid ejection due to the heat generated, which is important for practical use.

In this way, conventional methods have problems in terms of structure and high-speed recording.

The use of multi-nozzle recording heads has advantages and disadvantages in terms of the generation of satellite dots and fogging of recorded images, and there is a restriction that it can only be applied to applications that take advantage of these advantages.

Bubbles are generated in the recording liquid using thermal energy.

The method of ejecting the recording liquid by the force exerted during the volumetric expansion has a problem that must be solved as described in Japanese Patent Application Laid-Open No. 58-36464. That is, when the bubble disappears, the meniscus rapidly retreats, the surface condition of the meniscus is destroyed, and air inflow from the meniscus destruction port causes the meniscus to retreat too far into the liquid path, causing the size of the droplet to become inadequate. The droplets may become uniform, or there may be variations in the flying speed and direction of the droplets, and sometimes the recording liquid may not be ejected.
This method has the drawback of causing a significant drop in print quality.

Japanese Unexamined Patent Publication No. 58-36464 attempts to solve this drawback, but it does not disclose anything about the energy of the driving electric pulse, and it is difficult to actually prevent the meniscus from receding too much. , how much voltage should I apply and for how long?

Furthermore, various experiments conducted by the present inventors have shown that when the driving voltage is increased, the driving pulse width is lengthened, and the falling edge of the thermal signal is extended, the main bubbles that form droplets (thermal Following the first bubble (after applying the target signal), the second bubble (second bubble)
This secondary bubble has enough volume to move the receding meniscus toward the ejection port again, and as a result, the recording liquid is released from the ejection port in the form of a mist. We have discovered that the problem is that it is ejected and scattered (splash phenomenon). The above-mentioned drawbacks are also observed in various driving electric pulses as shown in Japanese Patent Application Laid-Open No. 58-36464, which have the drawback of deteriorating printing quality.

In addition, JP-A-58-11169 only provides a plurality of driving pulses for the reliability and long-term stability of the heating element, but does not disclose the above-mentioned drawbacks, and does not disclose the above-mentioned drawbacks by using multiple pulses. As a result, secondary bubbles and even tertiary bubbles were generated, resulting in a deterioration in print quality.

The present invention was made in view of the above-mentioned circumstances.
To prevent the meniscus from receding too much and to find the optimal energy timing for stable ejection at all times, to clarify them, to record high-quality images, and to propose a liquid jet recording method that achieves the above objectives at low cost. It was done for that purpose.

In order to achieve the above object, the present invention provides an ejection port for ejecting a recording liquid, a liquid path for guiding the recording liquid to the ejection port, and a method for applying thermal energy to the recording liquid. In a liquid jet recording device, a thermal energy generating body is used to generate bubbles, and the recording liquid is caused to fly from the ejection port by the acting force caused by the increase in the volume of the bubbles. inputting at least one or more auxiliary signals after the pixel signal inputted to the thermal energy generator in order to generate the thermal energy; The auxiliary signal is inputted before the bubble disappears, and further, the auxiliary signal is
A signal of v p N・tp>Vs”・ts (Vp: voltage of pixel signal, tp: pulse width of pixel signal e V @:
The voltage of the auxiliary signal, ts: the pulse width of the auxiliary signal);
(n-1)>Vsn”・tsn (n=2
.

3.) signal (Vs(n-1): voltage of the n-1th auxiliary signal, ts(n-1): pulse width of the n-111th auxiliary signal.

Vsn: voltage of the n-th auxiliary signal; tsn: pulse width of the n-th auxiliary signal).

First, the principle of ink ejection using a bubble jet will be explained based on FIG. 5 in FIG.

21 is a lid board, 22 is a heating element board, 27 is a selection (independent)
28 is a common electrode, and 29 is a heating element.

30 is ink, 31 is a bubble, and 32 is a flying ink droplet.

(,) is a steady state, in which the surface tension of the ink 30 and the external pressure are in equilibrium on the orifice surface.

In (b), the heater 29 is heated until the surface temperature of the heater 29 rises rapidly and boiling development occurs in the adjacent ink layer, and microbubbles 31 are scattered.

(Q) shows a state in which the adjacent ink layer that is rapidly heated on the entire surface of the heater 29 is instantaneously vaporized to form a boiling film, and the bubbles 31 grow. At this time, the pressure inside the nozzle increases by the amount of bubble growth, and the balance with the external pressure on the orifice surface is lost, causing an ink column to begin to grow from the orifice.

(d) shows a state in which the bubble has grown to its maximum, and ink 30 corresponding to the volume of the bubble is pushed out from the orifice surface. At this time, no current is flowing through the heater 29, and the surface temperature of the heater 29 is decreasing. The maximum value of the volume of the bubble 31 is slightly delayed from the timing of electric pulse application.

(e) shows a state where only bubble 3 has been cooled by ink etc. and has begun to contract.The tip of the ink column moves forward while maintaining the extruded speed, and the rear end of the column moves forward as the bubble contracts. Due to the decrease in internal pressure, ink flows back into the nozzle from the orifice surface, creating a constriction in the ink column.

In (f), the air bubbles 31 are further contracted, the ink comes into contact with the heater surface, and the heater surface is cooled even more rapidly. At the orifice surface, the external pressure is higher than the nozzle internal pressure, so the meniscus is largely moving into the nozzle. The tip of the ink column becomes a droplet and drops 5 to 1 droplets toward the recording paper.
It is flying at a speed of 0 m/sec.

In (g), the air bubbles have completely disappeared in the process of refilling the orifice with ink by capillary action and returning to the state of (a).

Next, the structure of the recording head will be explained based on the above principle diagram.

FIG. 6 is an overall perspective view of a recording head used in the present invention, and FIG. 7 is an exploded configuration diagram of the recording head, in which (a) is a lid substrate, (b) is a heating element substrate, and (C) is a lid. In Figure 6, which is a back view of the board, 23 is an ink supply port, 24 is an ink discharge port,
25 is a flow path, and 26 is a region for forming a liquid chamber.

Moreover, FIG. 8 is a configuration diagram of the above-mentioned heat generating body substrate, in which a heat storage Nj9, a heat generating body layer 10. The electrode layers 11 and 12, the heating element protection layer 13, and the electrode protection layer 14 are formed by photofabrication and semiconductor process technology.

Substrate materials include silicon, ceramics, glass, etc., but silicon is optimal in terms of high frequency response, heat resistance, heat dissipation, and mounting when the drive circuit described later is provided on the same substrate as the heating element. It is. In particular, thin film transistors (TFTs) that can be mounted with drive elements in high density are used.
It is extremely excellent when formed using NSISTOR). A thermal oxide film of Sin is formed as a heat storage layer on a silicon substrate. The heat storage layer is required to have contradictory characteristics, such as appropriately suppressing the escape of heat to the silicon substrate when the heating element is ON, and appropriately transmitting heat to the silicon substrate when the heating element is OFF. For this reason, since the thickness of the heat storage layer has a large effect on the generation and disappearance of bubbles, an appropriate thickness must be selected, and a thickness of 0.1 to 10 μm is usually preferred.

As a method for forming the heat storage layer, a sputtering method, a CVD method, a plasma CVD method, or the like may be used.

After forming a heating element layer and an electrode layer on the heat storage layer by a thin film forming method such as a sputtering method, a CVD method, a plasma CVD method, or a vacuum evaporation method, a desired pattern is obtained by selective etching.
Examples of materials constituting the heating element layer include tantalum nitride, nichrome, silver-palladium alloy, silicon semiconductor, metallic glass, tin oxide, and also hafnium and lanthanum.

Examples include metals such as zirconium, titanium, tantalum, tungsten, molybdenum, niobium, chromium, and vanadium, alloys thereof, and borides thereof. Among them,
In particular, metal borides are excellent as heating elements. Among them, the most excellent are hafnium boride, followed by zirconium boride, lanthanum boride, tantalum boride, and vanadium boride.

The resistance value of the heating element cannot be made high because the temperature must be raised rapidly and the current waveform must be a so-called unrounded waveform, that is, it must immediately follow the input drive signal. Furthermore, it is disadvantageous if the size is too small compared to reducing power consumption.

Therefore, it is usually 10 to 500Ω, preferably 15 to 150Ω.
The film thickness of one heating element layer, which is Ω, is generally 1000 to 3 μm, preferably 1 μm, considering the above resistance value, durability, etc.
The thickness is preferably 500 to 1 μm.

As the constituent material of the electrode layer, many commonly used electrode materials can be used, for example.

These include Afi, Ag, Pt, Cu, etc.

After forming the electrode, a protective layer 1 is applied so as to cover at least the heating element.
2 will be provided. The properties required of the protective layer are to effectively transfer the heat generated by the heating element to the recording liquid, to protect the heating element from the recording liquid, and to protect the heating element from damage when bubbles disappear. . Examples of materials constituting the protective layer include silicon oxide, silicon nitride, magnesium oxide, aluminum oxide, tantalum oxide, zirconium oxide, hafnium oxide, lanthanum oxide, yttrium oxide, manganese oxide, calcium oxide, aluminum nitride, boron nitride, etc. Examples include oxides, nitrides, and complexes thereof. Using these materials, a protective layer is formed by a film forming method such as a vapor deposition method, a sputtering method, a CVD method, a plasma CVD method, a gas phase reaction method, or a liquid coating method. After that, an electrode protection layer 14 is formed. The characteristics required of the electrode protective layer include excellent liquid resistance and heat resistance, and good electrical insulation. Therefore, it is required to have good film-forming properties, have few pinholes, and not swell or dissolve in the ink used. The materials constituting the electrode protective layer include:
Many materials that meet the above conditions can be used. For example, silicone resin, fluororesin, aromatic polyamide, addition polyimide, metal chelate polymer, titanate ester, epoxy resin, phthalate resin, thermosetting phenol resin, There are resins such as P-vinylphenol resin, Zylock resin, and triazine resin.

Furthermore, various organic compound monomers such as thiourea,
Thioacetamide, vinylferrocene, 1.3.5-trichlorobenzene, chlorobenzene, styrene, ferrocene, viroline, naphthalene, pentamethylbenzene,
Nitrotoluene, acrylonitrile, diphenylselenide, p-toluidine, p-xylene, N,N-dimethyl-p-toluidine, toluene, aniline, diphenylmercury, hexamethylbenzene, malononitrile, tetracyanoethylene, thiophene, benzeneselenol, tetra Fluoroethylene, ethylene, N-nitrosodiphenylamine, acetylene,! , 2,4-trichlorobenzene, propane, etc. can also be formed into a film by a plasma polymerization method.

However, if a high-density multi-orifice type recording head is to be produced, it is desirable to use an organic material, which is extremely easy to process using fine photolithography, as the material for forming the electrode protective layer, in addition to the above-mentioned organic materials. Specific examples of such organic materials include polyimide isoindoquinazolinedione (trade name: PIQ, manufactured by Hitachi Chemical), polyimide resin (trade name:
PYRALIN, manufactured by DuPont), polybutadiene oxide (
Preferred examples include (trade name: JSR-CBR, CBR-MOOI, manufactured by Japan Synthetic Rubber Co., Ltd.), Photonice (trade name: Toshi II), and other photosensitive polyimide resins.

Examples of materials for the lid substrate include glass, ceramic,
Silicon wafers, metal plates, etc. Among them, glass is excellent because it can be used in a large area, and because it is transparent, the state of bonding with the heating element substrate and the state of the flow path can be visually observed. As the glass, not only ordinary soda quartz glass but also silicate glass, high silicate glass, borosilicate glass, aluminosilicate glass, lead glass, and aluminoborosilicate glass can be used. l! Fine grooves that serve as flow channels are formed in the substrate. These fine grooves can be arbitrarily cut and formed using a microcutter, with a width of several μm or more, a depth of about 10 μm to 250 μm, and a pitch of 10 μm or more. Therefore, according to this manufacturing method, it is easy to obtain a multi-array type recording head in which extremely fine ink flow channels are integrated at a higher density than ever before (8 ZII- or more), and it is possible to easily obtain a multi-array type recording head in which extremely fine ink flow channels are integrated at a higher density than before (8 ZII- or more). It can considerably satisfy the current demands of the industry. Alternatively, the grooves can be formed by etching the glass substrate using photolithography and etching. The lid substrate thus produced is adhered to the heating element substrate.

The adhesion method is as follows.

After cleaning the flat plate, an anchor layer mainly composed of epoxy resin is applied to one side of the plate, and baked at 100° C. for 20 minutes.

Next, a bonding agent layer having the following composition is coated on the anchor layer to a thickness of approximately 3 μm to 10 μm.

Epicoat #1007 (trade name): 500 overlap parts Aromatic amine curing agent: 5 overlap parts Silane coupling agent 25 overlap parts Methyl ethyl ketone = 300 overlap parts After preliminary drying and semi-curing at 100°C for 5 minutes, apply to the coated surface. Diamond blade cutter [e.g. Disco
21115 model (product name), manufactured by Disco],
A predetermined number of long narrow grooves are formed by cutting. Note that the cut wall surface of this platform and flat plate, that is, the wall surface of the elongated narrow groove, can be obtained as a rough surface with a surface roughness of about 2 to 5 μm. It is almost impossible for chipping to occur.

After cutting the flat plate in this way, it is cut into a predetermined size as part A.

Incidentally, the groove is approximately 10 μm x 10 μm to 15 μm.
Cross-sectional area of 0μm x 150μm, pitch 30μm~
It is cut to 200 μm.

In addition, the bonding agent is not limited to those having the above-mentioned composition, but the bonding agent suitable for use here is a material that produces a bonding effect when heated, such as an epoxy resin adhesive,
These are organic compound adhesives such as phenolic resin adhesives, urethane resin adhesives, silicone resin adhesives, triazine resins, and BT resins, and inorganic compounds such as molten silver salts and low-melting glasses. .

15, which describes a method of making a channel wall that forms a channel on a heating element substrate using a photosensitive resin based on FIG. 9.
16 is a lower layer, and 16 is a photosensitive resin.

17 is a channel groove, 18 is a lid substrate, and 19 is a titanium-based coupling agent layer. Using a coating means such as a spinner or a roll coater, a photosensitive resin 16 containing a resin having cavitation erosion resistance according to the present invention, such as photosensitive polyamide varnish or photosensitive polyimide varnish, is laminated. . Although there is no particular restriction on the laminated thickness of the photosensitive resin 16, in consideration of practicality as an inkjet recording head, it is preferable to have a relatively thick layer of at least about 10 to 100 μm. Also used as photosensitive resin.

It is preferable that the photosensitive resin 16 can be laminated to such a thickness, and as the commercially available photosensitive resin 16, the above-mentioned photosensitive polyamide varnish, ie, Printite EF95. Toplon, nylon print (Nylonpr)
int), or photosensitive polyimide varnishes, i.e. Photonice VR-3140, Selectilux W
TR-2 is preferably used.

The substrate on which the photosensitive resin 16 is laminated in this way is subjected to a process such as exposure or development as described below to form an ink channel 17 made of the photosensitive resin. In addition, as shown below, the photosensitive resin 16 is Photoneese VR-3140.
The processing operation will be explained using the case where the ink flow path is formed as an example.
Needless to say, it can be any arbitrary value depending on the type of the item 6.

In other words, photosensitive resin Photoneese VR-3140
The conditions for the prebeta are not particularly limited, but in this example, the conditions were 80° C. for 80 minutes.

After completion of the preliminary beta, a photomask having a desired pattern is placed on the Photonease VR-3140, and then exposure is performed through this photomask.

After the exposure, the unexposed part of Photonice VR-3140 is treated with developer DV-505 for Photonice VR-3140.
Grooves that are to be used as ink flow channels are formed by developing the film using a etchant and dissolving and removing the unexposed portions.

After dissolving and removing the unexposed portions in this manner, post-baking is performed to harden the exposed portions of Photoneese VR-3140 remaining on the substrate 8, and the Photoneese VR-3140, which is an ink channel wall having a desired pattern, is formed on the substrate 8. A cured film of 3140 is formed. Post-bake conditions are not particularly limited, but in this example, 100°C, 30 minutes → 300°C,
It was carried out in three steps: 30 minutes → 400°C for 30 minutes.

A flat plate 18 serving as a cover for the ink flow path is laminated on the substrate 8 on which the ink flow path wall 16 made of the cured film of the photosensitive resin 16 is formed in this manner.

After forming a thermal oxide film of SiO to a thickness of 1 μm on a silicon substrate, hafnium boride was laminated to a thickness of 1500 μm as a heat generating layer by sputtering, and an AQ electrode was further formed to a thickness of 5000 μm by electron beam evaporation. The dimensions of the zero-heating part were 30 μm in width and 100 μm in length, and the resistance value including the resistance of the AQ electrode was 60Ω.

Next, keep! ! After forming the 11th layer of SiO to a thickness of 2 μm by sputtering, a second protective layer of T
A was sputtered to a thickness of 0.5 μm. Then electrode protection In
As such, photosensitive polyimide (trade name: PHOTONES manufactured by Toshi) was formed on the parts excluding the heat generating part. As described above, channel walls were formed on the heat generating substrate thus produced using a photosensitive dry film. On the other hand, as a lid substrate, a 50 μm thick photosensitive dry film was formed on glass as an adhesive layer (a binder layer to strengthen the bonding force with the photosensitive dry film in the channel), and the channel walls were provided. A head was formed by adhering to the heating element substrate using a UV curable adhesive.

The following recording liquid was supplied to this head.

The recording liquid used in the present invention is different from the recording liquid used in conventional recording methods, in addition to the selection of materials and the ratio of composition components so that it has the thermophysical properties and other physical properties described below. In addition to being chemically and physically stable, it also has excellent responsiveness, fidelity, and thread-forming ability, does not solidify in the liquid path, especially at the discharge port, and flows through the flow path at a speed that corresponds to the recording speed. The physical properties are adjusted so as to give the following properties, such as quick fixation on the recording member after recording, sufficient density, and good shelf life.

The recording liquid used in the present invention is composed of a liquid medium, a recording agent that forms a recorded image, and additives added to obtain desired characteristics. By selecting the type and composition ratio, it is possible to obtain any of aqueous, non-aqueous, soluble, conductive, and insulating properties.

Liquid media are broadly classified into aqueous media and non-aqueous media, but the liquid media used are those that are combined with other selected constituents so that the recorded recording liquid has the above-mentioned physical properties. The combination is selected from the following.

Such non-aqueous media include, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, 5ee-
Butyl alcohol, tart-butyl alcohol, isobutyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, etc. with 1 to 10 carbon atoms
Alkyl alcohol; for example, hydrocarbon solvents such as hexane, octane, cyclopentane, benzene, toluene, and quidylol; halogenated hydrocarbon solvents such as carbon tetrachloride, trichloroethylene, tetrachloroethane, and dichlorobenzene; for example.

Ether solvents such as ethyl ether, butyl ether, ethylene glycol diethyl ether, and ethylene glycol monoethyl ether; ketone solvents such as acetone, methyl ethyl ketone, methyl propyl ketone, methyl amyl ketone, and cyclohexanone; ethyl formate,
Methyl acetate, propyl acetate, phenylacetate.

Examples include ester solvents such as ethylene glycol monoethyl ether acetate; alcohol solvents such as diacetone alcohol; and petroleum hydrocarbon solvents.

These enumerated liquid media are appropriately selected and used so as to satisfy the compatibility with the recording agent and additives used and the characteristics described below as a recording liquid. Within the range where a recording liquid having the characteristics can be prepared, two or more types may be mixed as necessary, or these non-aqueous media and water may be mixed within the above conditions. May be used.

Among the above-mentioned liquid media, water or water/alcohol-based liquid media are preferred in consideration of pollution, ease of availability, ease of preparation, and the like.

As a recording agent, in addition to ensuring that the recording liquid to be prepared has the above-mentioned physical properties, it also prevents sedimentation in liquid channels and recording liquid supply tanks due to long-term storage, WX collection, and furthermore, transport pipes and liquids. Materials must be selected and used in relation to the liquid medium and additives so as not to cause clogging of the channels. From this point of view, it is preferable to use a recording agent that is soluble in the liquid medium, but even if the recording agent is dispersible or poorly soluble in the liquid medium, the particles of the recording agent when dispersed in the liquid medium are It can be used if the diameter is made sufficiently small.

The recording material that can be used is appropriately selected depending on the recording member so as to fully suit the recording conditions. Recording agents include dyes and pigments.

The dye that can be effectively used is one that satisfies the characteristics described below for the prepared recording liquid, and the dyes that are preferably used are 1, for example, direct dyes as water-soluble dyes, basic dyes, and acid dyes. Dyes, soluble vat dyes, acidic mordant dyes, mordant dyes, sulfur dyes as water-insoluble dyes, vat dyes, alcohol soluble dyes, oil soluble dyes 1 disperse dyes, etc., as well as thren dyes, naphthol dyes, and reactive dyes. Dyes, chromium dyes, 1:2 type complex salt dyes.

It is selected from 1:1 type complex salt dyes, azoic dyes, cationic dyes and the like.

Specifically, for example, Resolin Lil Blue PRL, Resolin Yellow PCG, Resolin Pink PRR, Resolin Green PB (manufactured by Bayer), and Sumikaron Blue 5.
-BG, Sumikaron Red E-EBL, Sumikalon Yellow E-4OL, Sumikalon Brilliant Blue 5-B
L (manufactured by Sumitomo Chemical), Diamond X Yellow-HG
-5E, Diamond Thread BN-8E (manufactured by Mitsubishi Chemical), Kayalon Polyester Light Flavin 4GL
, Kayalon Polyester Blue 3R-5F, Kayalon Polyester Yellow YL-8E, Kaya Set Turquis Blue 776, Kaya Set Yellow 902, Kaya Set Red 026, Prodion Red H-2B, Prodion Blue H-3R (Japan) (made by Kayaku), Revafix Golden Yellow P-R, Revafix Pril Red P
-B.

Revafix Pril Orange P-OR (Bayer I), Sumifix Yellow GR8, Sumifix B, Sumifix B, Sumifix Pril Red BS, Sumifix Pril Blue PB, Direct Black 40 (Jinmin Kagaku II), Diamond Mirror Brown 3G, Diamond Mirror Yellow G, Diamirror Blue 3R, Diamirror Prill Blue B, Diamirror Prill Red BB (manufactured by Mitsubishi Kasei), Remazol Red B, Remazol Blue 3R, Remazol Yellow GNL, Remazol Prill Green 6B (all manufactured by Hoechst) ), Cibaclon Pril Yellow, Cibaclon Pril Red 40E (manufactured by Ciba Geigy), Indico, Direct Tape Black E
-Ex, Diamine Black BH, Congo Red, Serious Black BH, Orange■, Amido Black IO
B, Orange RO, Metaneal Yellow, Pictoria Scarlet, Nigrosine, Diamond Black PBB
(manufactured by Egame), Diacit Blue 3G.

Diacitfast Green GW, Diacito Milling Navy Blue R, Indanthrene (Mitsubishi Kasei 11), Zapon dye (BASFI, Orazole dye (CII3AIl), Lanasin dye (manufactured by Mitsubishi Kasei),
Diacrylic Orange RL-E, Diacrylic Brilliant Blue 2B-E, Diacrylic Turkis Blue BG
-E (Mitsubishi Kasei M) and the like, those that provide the recording liquid with the above-mentioned physical properties can be preferably used.

These dyes are appropriately selected as desired and used after being dissolved or dispersed in the liquid medium used.

As pigments that can be effectively used, many of inorganic pigments and organic pigments are suitably used. Specific examples of such pigments include inorganic pigments such as cadmium sulfide, sulfur, selenium, zinc sulfide, cadmium sulfoselenide, yellow lead, zinc chromate, molybdenum red, Guinée green, titanium white, zinc white, and zinc white. Handle, chrome oxide green.

Red lead, cobalt acid, barium titanate, titanium yellow, iron black, #blue, litharge, cadmium red, silver sulfide, lead sulfate, barium sulfate, ultramarine blue, calcium carbonate,
Examples include magnesium carbonate, lead white, cobalt violet, cobalt blue, emerald green, and carbon black.

Most of the organic pigments are classified as dyes and often overlap with dyes, but specifically, the following are preferably used.

(,) Insoluble azo type (naphthol type) Brilliant Carmine BS, Lake Carmine FB, Brilliant Fast Scarlet, Lake Red 4R, Rose Red, Permanent Red R, Fast Red FO
R, Lake Bordeaux 5B, Vermilion No. 1, Vermilion No. 2, Toluidine Maroon.

(b) Insoluble azo type (anilide type) Diazo Yellow, Fast Yellow G, Fast Yellow 10G, Diazo Orange, Palkan Orange, Balazolone Red.

(c) Soluble azo type Lake Orange, Brilliant Carmilla 3B.

Brilliant Carmino 6B, Brilliant Scarlet G, Lake Red C, Lake Red D, Lake Red R
, Watching Red, Lake Bordeaux 10B, Bon Maroon L, Bon Maroon M.

(d) Phthalocyanine-based phthalocyanine blue, fast sky blue phthalocyanine green.

(e) Dyeing Lake Yellow Lake, Eosin Lake, Rose Lake, Violet Lake, Blue Lake, Green Lake, Sepia Lake.

(f) Mordant system Alizarin Lake, Madakamine.

(g) Vat-dyed type Industhrene series, Fast Blue Lake (GGS).

(h) Basic dye lake system Rhodamine Lake, Malachite Green Lake.

(i) Acid dye lake type Fast Sky Blue, Quinoline Yellow Lake, Quinacridone type, Dioxazine type.

The quantitative relationship between the liquid medium and the recording agent is determined based on conditions such as clogging of the liquid path, drying of the recording liquid in the liquid path, bleeding when applied to the recording member, and drying speed in addition to the formulation. The recording agent is usually 1 to 50 parts by weight, preferably 3 parts by weight, based on 100 parts of the liquid medium.
~30 parts, optimally 5 to 10 parts.

When the recording liquid is a dispersion system (a system in which the recording agent is dispersed in a liquid medium), the particle size of the dispersed recording agent depends on the type of recording agent, recording conditions, inner diameter of the liquid path, ejection opening diameter, and recording member. It is determined as desired depending on the type of recording material, etc., but if the particle size is too large, sedimentation of the recording material particles will occur during storage, resulting in uneven density and clogging of the liquid path. This is undesirable because it may cause the image to become distorted, or a density region may appear in the recorded image.

Taking these things into consideration, the particle size of the recording agent when used as a dispersion recording liquid is usually 0.01 to 30μ, preferably 0.01 to 20μ, and optimally 0.01 to 8μ. Furthermore, it is preferable that the particle size distribution of the dispersed recording agent be as narrow as possible, and usually D±3μ,
A preferable value is D±1.5μ (where D represents the average particle size).

Examples of the additives used include a viscosity & 11 agent 1 surface tension adjuster, a PH adjuster, a resistivity adjuster, a wetting agent, an infrared absorbing exothermic agent, and the like.

In addition to obtaining the above-mentioned physical property values, the viscosity modifier and surface tension modifier must also be able to flow through the liquid path at a sufficient flow rate depending on the recording speed, and prevent the recording liquid from going around at the discharge port of the liquid path. It is added for the purpose of preventing bleeding (spreading of the spot diameter) when applied to a recording member.

The viscosity modifier and surface tension modifier are selected from commonly known agents as long as they are effective and do not adversely affect the liquid medium and recording material used, so as to satisfy the desired properties. used.

Specifically, viscosity modifiers include polyvinyl alcohol, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, water-soluble acrylic resin, polyvinyl pyrrolidone,
Gum arabic starch and the like can be exemplified as suitable examples.

It is suitably selected and used as desired.

Examples of surface tension modifiers include anionic, cationic, and nonionic surfactants.Specifically, as anionic surfactants, polyethylene glycol nitrile sulfuric acid,
Ester salts, etc., cationic types such as poly2-vinylpyridine derivatives, poly4-vinylpyridine derivatives, etc., nonionic types such as polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan monoalkyl Examples include ester, polyoxyethylene alkylamine, and the like.

In addition to these surfactants, amine acids such as jetanolamine, propatoolamine, and morpholinic acid, and basic substances such as ammonium hydroxide and sodium hydroxideff, N-
Substituted pyrrolidones such as methyl-2-pyrrolidone are also effectively used.

These surface tension modifiers do not adversely affect each other or other constituents, and provide the above-mentioned physical properties to the recording liquid being formulated, so that a recording liquid having a desired value of surface tension is formulated. If necessary, two or more types may be mixed and used within the range specified above.

The amount of these surface tension mvs agents added is determined as appropriate depending on the type, other constituent components of the recording liquid to be prepared, and desired recording characteristics, but for 1 part by weight of the recording liquid, Usually o, ooot ~ 0.1 parts by weight, preferably 0
．． The amount is desirably 0.001 to 0.01 parts by weight.

The pH adjuster is used to maintain a predetermined pH value in order to maintain the chemical stability of the prepared recording liquid. It is added at the right time and in an appropriate amount within a range that does not deviate from the physical property values.

As the PH adjuster suitably used in the present invention,
Almost any pH can be used as long as it can control the pH value to a desired level without adversely affecting the recording liquid being prepared.

Specific examples of such pH adjusters include lower alkanolamines, monovalent hydroxides such as alkali metal aqueous compounds, and ammonium hydroxide.

These pH adjusters are added in a necessary amount so that the recording liquid to be prepared has a desired pH value within a range that does not deviate from the above-mentioned physical property values.

The lubricant to be used is one that is more effective than those commonly known in the technical field related to the present invention, especially one that is thermally stable, as long as the recording liquid to be prepared does not deviate from the various physical properties listed below. are preferably used. Specific examples of such lubricants include polyalkylene glycols such as polyethylene glycol and polypropylene glycol; alkylene glycols in which the alkylene group has 2 to 6 carbon atoms such as butylene gellicol and hexylene glycol; for example, ethylene Lower alkyl ethers of diethylene glycol such as glycol methyl ether, diethylene glycol methyl ether, and diethylene glycol ethyl ether; Glycerin; Lower alcohol oxytriglycols such as methoxytriglycol and ethoxytriglycol; N-vinyl-2-
Examples include pyrrolidone oligomer; and the like.

These lubricants are added in the required amount as desired so that the recording liquid satisfies the desired characteristics.
The amount added is usually 0.1 to 1 1 based on the total weight of the recording liquid.
0 wt%, preferably 0.1-8 wt%, optimally 0.2
It is desirable that the content be ~7wt%.

In addition to being used alone, the above lubricants may be used in combination of two or more types provided that they do not adversely affect each other.

In the recording liquid used in the present invention, the above-mentioned additives are added in necessary amounts as desired, and in addition, additives that have excellent formation properties and film strength of a recording liquid film when attached to a recording member are used. For example, resin polymers such as alkyd resins, acrylic resins, acrylamide resins, polyvinyl alcohol, and polyvinylpyrrolidone may be added.

The recording liquid used in the present invention has specific heat, coefficient of thermal expansion, thermal conductivity, viscosity,
When recording using surface tension, pH, and charged recording droplets, it is desirable that the composition be prepared so that characteristic values such as surface tension, pH, and specific resistance fall within the range of characteristic conditions.

That is, these characteristics have important relationships with the stability of the stringing phenomenon, responsiveness and fidelity to thermal energy effects, image density, chemical stability, fluidity within the liquid path, etc. Therefore, in the present invention, it is necessary to pay sufficient attention to these matters when preparing the recording liquid.

It may be desirable to have the above-mentioned properties of the recording liquid that can be effectively used in the present invention as shown in Table 1 below, but all of the listed physical properties are shown in Table 1 below. It is not necessary to satisfy the numerical conditions shown, and it is sufficient that some of these physical properties take values that satisfy the conditions in Table 1, depending on the required recording characteristics. Ryōsei et al. specific heat,
Regarding the coefficient of thermal expansion, thermal conductivity, viscosity, and surface tension, it is desirable that the values shown in Table 1 be specified.Of course, among the above properties of the prepared recording liquid, the values shown in Table 1 should be specified. It goes without saying that the more satisfied you are, the better the recording will be.

Table 1 Using the above recording head and recording liquid, driving voltage 20
V, pulse width 5 usac, il! It was driven at a dynamic frequency of IKHz (*power method 1), and a graph of the drive signal and bubble volume change at this time is shown in FIG.

As shown in Figure 10, the time when bubbles reach their maximum tp□=10
, cisec, and the time to disappear, tp, = 244 sec, and the volume expansion time and contraction time were almost the same.

In order to prevent the meniscus from receding too much as disclosed in Japanese Patent Application Laid-Open No. 58-36464, when a drive signal as shown in FIG. A splash phenomenon was observed from the orifice, and the image quality deteriorated.

Furthermore, as shown in Fig. 12, a similar phenomenon was observed when the drive signal was formed using multiple pulses (driving method 2).
, will be described below based on embodiments of the present invention.

FIG. 1 is a diagram showing drive signals and changes in bubble volume for explaining an embodiment of a liquid jet recording apparatus according to the present invention. Here, tl is the auxiliary signal application time, and tPz is the first
The time when the bubble reaches its maximum, tP, is the bubble disappearing time when only the driving signal is applied - tPg is the bubble disappearing time when the auxiliary signal is input, tP4 is the time when the secondary bubble reaches its maximum - tPs is,
This is the time at which the volume between the first bubble and the secondary bubble becomes minimum.

A driving signal of 20 V and a pulse width of 5 μsec was applied. Furthermore, in order to prevent the meniscus from retreating too much according to the present invention, a second pulse with a voltage of 20 V and a pulse width of 3 μsec is input at time t1 (1@power method 3), and the input time t1 of the second pulse is as follows: From the experimental results in Table 2, −tpx<
This is within the range of tl≦tPm, that is, when the bubbles are contracting after reaching the maximum volume. More preferably, tpx<
By setting t1≦(2tpz”tPI)/3, the bubbles can be more smoothly contracted without excessively contracting the bubbles.

As mentioned above, in addition to the normal drive signal, by applying a small pulse (hereinafter referred to as an auxiliary signal) to prevent the meniscus from receding too much at the above time, the bubble disappearance time jPa is equal to the bubble contraction time tP of the drive signal only. It was extended to 120 μsec, about 6 times as long, and the contraction was extremely smooth. Furthermore, as shown in Figure 2.

As the second auxiliary pulse between the bubble volume maximum time tP and jPs by the auxiliary signal, 20V, pulse width 3μsec.
By inputting the auxiliary signal, the meniscus could be further gradually retreated (driving method 4).

The above discharge results using the power method were very good as shown in Table 3 below. Also.

These are particularly preferred embodiments that can be implemented without changing the circuit configuration.

Table 3 Furthermore, in driving method 3, when the voltage of the auxiliary signal is 15V,
When the volume change of the bubbles was observed, the results were as shown in Figure 3, and a smoother contraction curve was obtained. Furthermore, the stability of droplet ejection speed and direction was investigated by changing the voltage and/or pulse width of the auxiliary signal, and the results shown in Table 4 were obtained. Here, O is extremely stable in both speed and direction, 0 is very slight variation but has little effect on image quality, Δ is variation and affects image quality, and × is extremely unstable due to satellites, splash phenomena, etc. Stable.

From this result, the voltage of the drive signal is VP, and the pulse width is tp.
It has been found that good printing quality can be obtained when the voltage V s and pulse width ts of the auxiliary signal satisfy Vp''tp≧Vs''ts.

In addition, in the driving method 4, the second. By applying the third auxiliary signal that satisfies the above-mentioned range, it was possible to achieve extremely smooth bubble contraction, and to prevent ejection failure due to rapid retreat of the meniscus.

These driving methods have the effect that the energy consumed by the auxiliary signal can be reduced compared to driving method 3 and driving method 4.

FIGS. 4(a) to 4(d) are examples showing the driving method of the present invention, and good ejection was obtained in all cases.

(a) shows two auxiliary signals applied between jPz and 1-Pa.

In (b), the second auxiliary signal has lower energy than the first auxiliary signal in (a).

(c) is Vp”tp≧Vs”ts between tpl and tpa
In addition, an auxiliary signal tp(ts) is applied.

(d) is the driving method 4, and Vs(n-1)”t
5(n-1)) Vs"nt-t 5n(n=2.3.-
) is applied with an auxiliary signal that satisfies

Here, Vs(n-1): Voltage t of the n-1th auxiliary signal 5(n-1): Pulse width Vsn of the n-1th auxiliary signal Voltage tsn of the Sn-th auxiliary signal: n
Pulse Width of the Auxiliary Signal - 11 As is clear from the above explanation, according to the present invention, the meniscus retreats without causing discharge failures such as splash phenomenon due to secondary and tertiary bubbles. We were able to solve the ejection failure caused by overflow. Therefore, stable ejection could be performed at all times, and the image quality could be significantly improved. Furthermore, the present invention has an extremely excellent effect in that a high-quality image can be obtained without requiring a special circuit and therefore without increasing costs.

[Brief explanation of drawings]

FIG. 1 is a diagram showing drive signals and bubble volume changes for explaining an embodiment of a liquid jet recording device according to the present invention;
Figure 2 is a diagram showing the change in bubble volume when the first and second auxiliary signals are used, Figure 3 is a diagram showing the change in bubble volume when the voltage of the auxiliary signal is changed, and Figure 4 is a diagram showing the change in bubble volume when the voltage of the auxiliary signal is changed. figure(,)~
(d) is a diagram showing the driving method of the present invention, FIG. 5 is a principle diagram of bubble jet ink ejection and bubble generation/disappearance in the recording head, FIG. 6 is a perspective view of the recording head, and FIG. 7 is a diagram showing the driving method of the present invention. , FIG. 8 is an exploded configuration diagram of the recording head, (a) is a lid substrate, (b) is a diagram showing a heating element substrate, (c) is a back view of the lid substrate of the recording head, and FIG. 8 is a configuration of the heating element substrate. FIG.
0 is a diagram showing driving method 1, FIG. 11 is a diagram showing generation of secondary bubbles, and FIG. 12 is a diagram showing driving method 2. 8... Substrate, 9... Heat storage layer, 10... Heat generating layer,
11゜12... Electrode, 13... Heating element protective layer, 14
... Electrode protective layer, 15 ... Lower layer, 16 ... Photosensitive resin, 17 ... Channel groove, 18 ... Lid substrate. Figure 1 Patent applicant Ricoh Co., Ltd.

Claims (1)

[Claims] 1. An ejection port for ejecting recording liquid, a liquid path for guiding the recording liquid to the ejection port, a thermal energy generator for applying thermal energy to the recording liquid, and the thermal energy generator. In a liquid jet recording device that generates air bubbles and causes the recording liquid to fly from the ejection port by the acting force accompanying the increase in the volume of the air bubbles, a pixel signal input to the thermal energy generator in order to generate the air bubbles. 1. A liquid jet recording device, wherein at least one or more auxiliary signals are input after the step.