JPH08112903A - Ink jet recording method - Google Patents

Abstract

PURPOSE: To carry out the high speed recording by reducing the irregularity of a dot diameter or misdirection, in an ink jet recording method, by suppressing the vibration of an ink meniscus after the emitting force applied to ink is cut off. CONSTITUTION: An orifice plate 22 is provided to the front of a recording head and a control electrode 21 is arranged to the periphery of each of the openings thereof. A medium 25 to be recorded is arranged in a movable manner in opposed relation to the recording head and a rear electrode 24 is provided on the rear surface side thereof. The recording head is filled with a hot-melt ink. (A) shows such a state that no pulse voltage is applied across the control electrode 21 and the rear electrode 24 and (B) shows such a state that pulse voltage is applied across both electrodes and ink forms stringing to fly by an applied voltage pulse to apply printing to the material 25 to be recorded. As the pulse voltage, a waveform reducing gradually after the completion of the application of the max. pulse voltage is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording method, and in particular, a recording head is filled with ink, the recording head has an ejection port for ejecting the ink, and the ink forms a meniscus at the ejection port. The present invention relates to an ink jet recording method in which recording is carried out by causing the recording head to generate a towing thread and causing the ink to fly.

[0002]

2. Description of the Related Art A so-called inkjet recording apparatus for recording an image on a recording medium by ejecting ink from an orifice or a slit is widely used because of its simplicity and high speed. Various methods have been proposed as inkjet recording methods. Among them, the so-called electrostatic suction type inkjet recording apparatus, in which an electric field is applied between the control electrode inside the print head and the back electrode on the back surface of the recording medium to draw out the ink by the Coulomb force and print, is particularly configured. It is simple, the head can be easily manufactured, a page width head can be easily created, high-speed printing is possible, and the dot diameter can be controlled by pulse width modulation.
It has attracted attention because of its features such as.

The recording head of the electrostatic suction type ink jet recording apparatus is described in "Journal of the Institute of Image Electronics Engineers," Vol. 5, No. 2 (1971).
6), pp. 43-51, using a nozzle, for example, "Collection of IEICE Transactions"'8.
3- / 1, Vol. J66-C, No1, 47th to 54th
Those using slits are known as described in the page.

The electrostatic suction type ink jet recording method will be described with reference to FIG. In the figure, 21 is a control electrode, 22 is an orifice plate, 23 is an insulating protective layer, 24 is a back electrode, and 2 is a back electrode.
Reference numeral 5 is a recording medium, and 26 is ink. FIG. 5 shows a cross section of one pixel of the recording head. The orifice plate 22 is provided as a front plate of the recording head and has an opening for ejecting ink. The control electrode 21 is arranged around the opening of the orifice plate 22 to lead out to the outside, but an insulating protective layer 23 is provided on the lead portion. Orifice plate 22
The recording medium 25 is arranged so as to face the recording head so as to be movable relative to the recording head, and the back electrode 24 is provided on the back surface side thereof. The back electrode 24 is provided as a common electrode for all pixels. The ink 26 filled in the recording head is a heat-melting type ink in this example, but it does not have to be a heat-melting type ink.

FIG. 5A shows a control electrode 21 and a back electrode 2.
4 indicates a state in which both are connected to the ground potential and no voltage is applied between both electrodes. The ink 26 does not contact the recording medium 25 in a state where a meniscus is formed in the opening of the orifice plate 22.

FIG. 5B shows a state in which a voltage is applied between both electrodes. In this example, +400 is applied to the control electrode 21.
V, -400V is applied to the back electrode 24, and a potential difference of 800V is applied between both electrodes. Due to the electric field due to this potential difference, the ink forms a towing thread and flies to print on the recording medium 25. When the recording speed for printing is increased, that is, the time for forming the ink meniscus is shortened, the meniscus of the ink after the pulse voltage is cut off for printing becomes a steady state as shown in FIG. 5B. It becomes unstable before.

This unstable state will be described with reference to FIG.
The solid line shows the applied pulse voltage waveform, and the broken line shows the liquid surface position at the center of the ink meniscus. By applying the pulse voltage, the ink meniscus extends and forms a string, reaches the position of the recording medium, and printing is performed. After the pulse voltage is cut off, the ink meniscus vibrates and returns to the steady position in the final state. There is no problem if the next pulse voltage is applied when the ink meniscus returns to the steady position, but if the recording speed of printing is increased, the next pulse voltage should be applied in the vibration state of the ink meniscus. become. In the vibrating state, since the position of the ink meniscus fluctuates, the formation of the ink tug by the next pulse voltage is not constant, so that the dot diameter variation and misdirection ( There is a problem that a phenomenon in which dots are formed at positions deviating from the positions where they should be originally formed occurs.

In order to shorten the vibration time of the ink meniscus, it is possible to increase the viscosity of the ink, reduce the nozzle opening diameter and slit width, increase the nozzle length and slit length, and the like. Both of these are factors that delay the supply of ink, and do not lead to an increase in recording speed as a whole. Therefore, it only indicates that there is a limit to the recording speed.

In the above-mentioned "Electronic Electronics Society of Japan", Vol. 5, No. 2, (1976), pp. 43-51, by applying a bias voltage having a constant magnitude even after the pulse voltage for printing is cut off, A method is disclosed in which the electrostatic attraction force exerted by the bias voltage accelerates the re-supply of the ink meniscus to improve the high-speed response.

Such a voltage application method improves the high-speed response to some extent as compared with the conventional method. However, FIG.
As shown in (B), when the pulse voltage is switched to the bias voltage, the ink meniscus vibrates due to the difference between the pulse voltage and the bias voltage. In the case of printing, the high-speed response also deteriorates, and if the difference between the pulse voltage and the bias voltage is made small, the ink will continue to fly even after the pulse voltage is cut off and the dots will become large, so that dots of the desired size can be obtained. I can't.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and in an ink jet recording method, the vibration of the ink meniscus after the interruption of the ejection force applied to the ink is suppressed to reduce the dot diameter. The purpose is to realize high-speed recording by reducing variations and misdirection.

[0012]

According to a first aspect of the present invention, the recording head is filled with ink,
The recording head has an ejection port for ejecting the ink, the ink is held so as to form a meniscus at the ejection port, and a recording yarn is ejected from the recording head by causing a thread to be generated in the ink. In the inkjet recording method to be performed, after the ink is ejected, a force facing the return of the ink having the towed string to the ejection port is applied to the ink.

According to a second aspect of the invention, the recording head is filled with ink, the recording head has an ejection port for ejecting the ink, and the ink is held so as to form a meniscus at the ejection port. In an ink jet recording method in which a potential difference is applied between the recording head and a counter electrode which is arranged to face the ink, a string is generated in the ink to fly the ink to perform recording, and a pulse voltage for ejecting the ink is a maximum pulse voltage. It is characterized in that it has a waveform that gradually decreases after the voltage application is completed.

In the ink jet recording method according to the first aspect of the present invention, electrostatic attraction, static pressure, air flow or magnetic force, or a combination of these forces can be used as the ink attraction force.

Further, in the ink jet recording method according to the first aspect, the force of sucking the ink can be gradually reduced after the ink has been ejected. In the inkjet recording method according to the first or second aspect, as the ink, a hot melt ink that is solid at room temperature and melts by heating can be used.

[0016]

According to the present invention, as a result of the inventors' earnest research on the flying condition of the ink, it is opposed to the ink returning from the state of the towed thread to the ink ejection port side after the ink flying. The inventors have found a method of reducing the vibration of the ink meniscus by applying a force.

Further, by controlling the waveform of the pulse voltage for ejecting the ink, the maximum pulse voltage is applied so as to gradually decrease from the end of the application, and the vibration of the meniscus due to the surface tension of the ink is forcibly reduced. It has been found that the meniscus of the ink can be in a steady state by the time the next pulse voltage is applied.

The operation of the present invention will be described with reference to FIG. 7 by taking the case where the present invention is applied to an ink jet recording method of the electrostatic suction type as an example. As described above, FIG. 6A is an explanatory diagram showing the pulse voltage waveform and the vibration of the liquid surface at the center of the ink meniscus when the pulse voltage for ejecting ink is instantly turned off. As described above, the problem caused by the vibration of the liquid surface of the ink meniscus is as described above. FIG. 7A is an explanatory diagram showing a pulse voltage waveform and fluctuations in the liquid level at the center of the meniscus when the pulse voltage for ejecting ink is applied so as to gradually decrease from the end of application of the maximum pulse voltage to the minimum voltage. is there.

Here, the equation showing the vibration of the meniscus when ink is re-supplied through the circular tube is shown as the first equation.

[Equation 1] Where h is the height of the meniscus, μ is the viscosity of the ink, and ρ
Is the ink density, a is the tube radius, γ is the surface tension, l is the tube length, and ΔP is the ink supply pressure. The first term on the left side is the inertial term, the second term is the viscous term, and the third term is the surface tension term.

This solution is divided into three cases according to the positive / negative of the discriminant D shown as the second equation below.

[Equation 2] In the second formula, in order to record at high speed, when the ink viscosity μ is reduced and D <0, vibration of the liquid surface of the meniscus occurs. Conversely, the ink viscosity μ is increased and D> 0.
Then, it takes time for the meniscus liquid surface to reach a steady state, and the recording speed decreases. The feature of the present invention is to reduce the liquid surface vibration and bring the liquid into a steady state in a short time at a low ink viscosity that causes the vibration of the liquid surface of the meniscus.

In the second equation, D is brought close to 0 in order to reduce the meniscus liquid surface vibration and bring it to a steady state in a short time. Therefore, in the present invention, the maximum pulse voltage is applied so that it gradually decreases from the end, and the first equation,
It is preferable to apply an electrostatic attraction force that cancels the surface tension γ of the second equation.

That is, in FIG. 7A, since the ink meniscus is always controlled by the force of ejecting the ink to the recording medium side even after the application of the maximum pulse voltage, the ink is recorded on the recording medium. It is possible to maintain the balance of the force with the surface tension that tends to pull the ink meniscus to the opposite side, and the ink meniscus can be brought to a steady state as shown in FIG. 5A in a short time.

The minimum voltage shown in FIG. 7A is a voltage whose magnitude is equal to or greater than 0 and equal to or less than the magnitude of the maximum pulse voltage.
FIG. 7B is an explanatory diagram when the minimum voltage is a constant value other than 0. As shown in this figure, the maximum pulse voltage may be gradually reduced to 0 V after the end of application, but more preferably, in order to suppress unnecessary vibration due to noise of the ink meniscus, it is shown in FIG. 7 (A). like,
It is better to give a minimum voltage greater than zero.

Further, the maximum pulse voltage and the minimum voltage in the present invention may be voltages formed by the sum of the voltages applied to the control electrode and the counter electrode of the recording head. When it is grounded, the voltage is applied to the other electrode. Also,
Even if there are more than two electrodes, such as a third electrode,
The present invention can be applied as the sum of the voltages applied to the respective electrodes.

The magnitude of the minimum voltage Vmin and the time Pe from the end of application of the maximum pulse voltage to the minimum voltage Vmin gradually decrease from the end of application of the maximum pulse voltage to the end of application of the next maximum pulse voltage. In addition, Vmin and Pe may be determined so that the flight of the ink is temporarily stopped.

The waveform of the time from the end of application of the maximum pulse voltage to the minimum voltage of the pulse voltage is the first
Since the surface tension term in the equation is proportional to the height h of the meniscus, it is considered that the surface tension term should be smaller than the height h.
That is, the pulse voltage waveform may be linearly reduced from the end of application of the maximum pulse voltage until the pulse voltage reaches the minimum voltage. Further, it may not be a perfect straight line, and may be an exponential function, a higher-order function, an exponential function, a step function, or the like, or an appropriate combination thereof. Furthermore, the voltage decrease does not necessarily start from the voltage value of the maximum pulse voltage, and may decrease from an intermediate value between the maximum pulse voltage and the minimum voltage. After returning to step 1, the voltage pulses that are successively reduced may be superimposed. Further, it may be a triangular waveform having no width in the maximum pulse voltage portion. Therefore, this method does not require complicated pulse voltage waveform control.

However, the present invention is not limited to the above, and a pulse voltage waveform may be applied in consideration of the inertia term, the viscosity term, the ink supply pressure and the like. By adjusting the ink viscosity, the ink density, the radius of the tube, the surface tension, the length of the tube, and the like so that D of the second equation approaches 0 in advance, it is possible to further solve the problem.

In the present invention, the suction force for ejecting the ink is not limited to the electrostatic attraction method of ejecting the ink by the electrostatic attraction force, and the pulse-on-demand method using a piezoelectric element or the electrostatic attraction method is used. A thermal electrostatic attraction method in which ink is ejected by a combination of attractive force and thermal energy, a static control method in which ink is raised by electrostatic attraction force and the raised ink is ejected by an air flow, and ink is magnetic When the body is included, various methods such as a method of ejecting ink by using magnetic force can be used.

Further, in the present invention, the attraction force applied to the return of the ink having the towed threads to the ejection port after the ink has been ejected is not limited to the electrostatic attraction force by the applied voltage. , Various forces that can act on the ink meniscus, such as using static pressure to form the ink meniscus, flowing an air stream around the ink meniscus, or magnetic when the ink contains magnetic material By applying a force to the ink meniscus as described above by using force, or by combining these forces, including the electrostatic attraction force, the vibration of the ink meniscus is suppressed, and the time to shift to the steady state is reduced. It can be shortened.

[0030]

FIG. 1 is a schematic diagram showing the overall structure of a color ink jet recording apparatus to which the ink jet recording method of the present invention is applied. In the figure, 1 to 4 are four-color recording heads, 1 is a black recording head, 2 is a yellow recording head, 3 is a magenta recording head, and 4 is a cyan recording head. Reference numeral 5 is an intermediate transfer member, 6 is an intermediate transfer member heater, 7 is a cleaner, 8 is a recording medium, and 9 is a back roller.

Four color recording heads 1 to 1 for color printing
Reference numerals 4 are arranged in parallel with each other so as to face the intermediate transfer body 5, and output inks of respective color components onto the intermediate transfer body 5 in accordance with an image signal from a host computer (not shown). The shape of the intermediate transfer body 5 is a drum shape, but an appropriate shape such as a belt shape is used. Intermediate transfer member 5
Is an ink which is heated by the intermediate transfer body heater 6 provided inside and printed by the recording heads 1 to 4.
It is pressed against the intermediate transfer member 5 and transferred onto the recording medium 8.
The cleaner 7 is provided to remove residual ink on the surface of the intermediate transfer member 5, paper dust, foreign matter, dust, and the like.

FIG. 2 is a configuration diagram showing an example of the recording heads 1 to 4 in FIG. 1, and FIG. 3 is an explanatory diagram of a printing state by the recording head of FIG. In the figure, 5 is an intermediate transfer member, 10 is powder ink, 11 is molten ink, 12 is a head heater,
Reference numeral 13 is a pixel drive board, 14 is a control electrode, 15 is a flexible substrate, 16 is an orifice, 17a is an ink thread, 17b is an ink dot, 18 is a drum base material of an intermediate transfer body, and 19 is a surface of an intermediate transfer body drum. It is a layer.

In the embodiment shown in FIGS. 2 and 3, the powder ink 10 is supplied to the ink chambers of the recording heads 1 to 4 by a powder ink supply device (not shown). The powder ink 10 can be prepared, for example, by using linear polyethylene as a main component and adding each color dye as a colorant, an antioxidant, a viscosity modifier, and the like. As a result of differential thermal analysis (DTA),
The melting point of this ink was endothermic from 100 ° C to 104 ° C, and the peak was 102 ° C. The surface tension during melting was 26 dyne / cm (120 ° C.). The composition of the ink used in this example is shown below. Oxidized polyethylene wax 98% by weight Black dye PEW BLACK (Mitsui Toatsu Co., Ltd.) 2% by weight

A major feature of this ink is that it has a property of plastically flowing even after being solidified at room temperature, and it can be crushed without destroying ink dots once formed on a recording medium by applying pressure. In addition to polyethylene, fatty acid metal salts, carnauba wax, and wax can be used as the main component of the ink.

The head heater 12 is a thick film resistor formed on a flexible substrate 15 made of PI (polyimide), and is energized by a head heater driving circuit (not shown) during standby of the recording apparatus and during printing operation. Then, the powder ink 10 is heated above its melting point to form the molten ink 11.

On the other hand, an orifice 16 is formed in the flexible substrate 15 of PI. In this embodiment, the flexible substrate 15 can be made of photosensitive polyimide, and the orifice 16 is formed by a photosensitive polyimide developing process. A liquid-repellent layer (not shown) is formed on the surface of the flexible substrate 15 facing the intermediate transfer member 5 to prevent the molten ink 11 from flowing out of the recording heads 1 to 4 due to power or surface tension. ing. The liquid repellent layer can be formed of, for example, a fluororesin thin film,
The critical surface energy obtained by measuring the contact angle is 1
It was 5 dyne / cm.

The control electrode 1 is formed on the surface opposite to the PI flexible substrate 15 (the surface inside the recording heads 1 to 4).
4, the orifices 16 and the control electrodes 14 are arranged at a desired dot interval of the recording apparatus in a direction perpendicular to the paper surface over the maximum width of the recording medium, and operate in parallel. Improves printing speed. Further, in this embodiment, the control electrodes 14 are provided one by one so as to communicate with one orifice 16 and are processed into a shape surrounding the circular orifice 16. The control electrode 14 can be formed, for example, by adhering a copper foil to the flexible substrate 15 with an epoxy resin adhesive and performing a photoetching process.

Further, the control electrode 14 is pressed against the pixel drive board 13 via an anisotropic conductive film. here,
The pixel drive board 13 drives a large number of control electrodes 14 with a high voltage (in this embodiment, a pulse voltage waveform that linearly and gradually decreases from a voltage of about 400V).
In this embodiment, the pixel drive board 13 has a high withstand voltage drive element array and a shift register for serial / parallel conversion of image data formed on a glass substrate by a thin film transistor (TFT) technique.

On the other hand, the intermediate transfer member 5 can be formed of, for example, an aluminum metal roll. When formed from an aluminum metal roll, the critical surface energy was 50 dyne / cm or more in contact angle measurement.
A bias pulse of -1 KV is applied to the intermediate transfer member 5.

Based on such a configuration, + according to the image information
When a 400 V pulse signal is applied from the pixel drive board 13 to the control electrode 14, the melted ink 11 facing the orifice 16 receives the Coulomb force and is ejected from the orifice 16 to form the ink draw string 17a and the intermediate transfer member. Fly toward 5. Then, the molten ink 11 adhered to the intermediate transfer body 5 by the tug 17a is immediately solidified, so that a raised ink dot 17b is formed on the surface layer 19 of the intermediate transfer body 5.

When performing color recording, ink of each color is attached to the intermediate transfer member 5 from the recording head. At this time, subtractive color mixing is performed on the intermediate transfer member 5. The intermediate transfer body 5 has a precise feed amount, and a constant environment is set by the pressurizing means. Further, since the intermediate transfer body 5 is less likely to be stretched or contracted due to environmental changes as compared with paper or the like, dimensional changes due to external disturbances may occur. Few. Therefore, when a color image is formed, the registration of each color (registration) is performed.
When performed above, it is much easier than when subtractive color mixing is performed on paper, and moreover, it can be performed with high accuracy.

FIG. 4 is an illustration of an example of transfer fixing from the intermediate transfer body 5 to the recording medium 8. In the figure, parts similar to those in FIGS. 1 to 3 are designated by the same reference numerals, and description thereof will be omitted. 1
7c is an ink dot, 9a is a steel roll, and 9b is a resin layer. The ink dots 17b printed on the surface layer 19 of the intermediate transfer body 5 show how transfer and fixing from the surface layer 19 of the intermediate transfer body 5 to the recording medium 8 is performed. The recording medium 8 using plain paper or the like is fed between the intermediate transfer body 7 and the back roll 9 by a paper feeding device (not shown). The back roll 9 is, for example, a steel roll 9a whose surface is coated with a resin layer 9b made of an elastic material.
Is pressed against the intermediate transfer body 7 from the back side by a pressure device (not shown). For the resin layer, for example, polyacetal resin is used.

In this way, the recording heads 1 to 4 for each color are
The image of the ink dots formed by the transfer from the intermediate transfer body 7 to the recording medium 8. At this time, the ink dots 17b solidified on the surface layer 19 of the intermediate transfer body drum are crushed and spread by the pressure of the back surface roll 9, and the ink dots 17b are substantially flat on the recording medium 8. 10c is formed.

In one embodiment of the pulse voltage for ejecting ink in the recording head in the ink jet recording apparatus described in FIGS. 1 to 4 and the recording head described in FIG. 5, its voltage waveform will be described in FIG. Illustrated.

FIG. 8 is a specific example of the voltage waveform in the embodiment described in FIG. 7 (B). In this specific example, the print cycle T is 10 ms. Maximum pulse voltage value is 400V
The maximum pulse voltage application time Pmax is 1 ms.
After the maximum pulse voltage mark is applied for 1 ms, 400 V to 0 for 4 ms from the end of maximum pulse voltage application.
It is a pulse voltage waveform that linearly decreases to V.

In order to see the effect of reducing variations in dot diameter according to this specific example, 50 dots in diameter on the intermediate transfer member 5 were measured for each of the specific example and the conventional example. As a result, in the pulse voltage waveform of the conventional example, the average dot diameter on the intermediate transfer member 5 is 40 μm, and the variation of the dot diameter is ± 20%.
On the other hand, in the pulse voltage waveform of the specific example, the variation in dot diameter could be kept within ± 5%.

In the present invention, the process of decreasing from the end of application of the maximum pulse voltage to the minimum voltage is not limited to the linearly decreasing waveform. Exponential or higher-order function,
It may be a waveform that decreases in a curve such as an exponential function. Figure 9,
FIG. 10 is an example in which the voltage decreases with a curve of a higher-order function.
FIG. 11 shows a pulse voltage waveform that decreases with a step function.

As described above with reference to FIGS. 7 to 11, the waveform that gradually decreases from the end of application of the maximum pulse voltage decreases linearly, curvilinearly, stepwise, or the like. Waveforms can be used.
Of course, a waveform combining these may be used.

Furthermore, the voltage reduction does not necessarily have to start from the voltage value of the maximum pulse voltage. As shown in FIG. 12, the waveform may be a value that decreases from an appropriate value between the maximum pulse voltage and the minimum voltage, and as shown in FIG. You may superimpose the voltage pulse which decreases one by one. In addition, in FIG.
As shown in FIG. 15, the maximum pulse voltage may be a triangular waveform having no width. Therefore, in this example,
It is not necessary to control a complicated pulse voltage waveform.

FIGS. 16, 17 and 18 are explanatory views of a recording head according to another embodiment of the present invention. In the figure, the same parts as those in FIG. 27 is a hydrostatic pressure generating means, 27a is a hydrostatic pressure pump, 27b is a diaphragm,
28 is an air flow, 28a is a cover plate, and 29 is a magnetic force generating means.

FIG. 16 shows an embodiment using a hydrostatic pressure generating means. Inside the recording head, the ink can be in a liquid state even when the molten ink is used. Therefore, by applying a hydrostatic pressure to a part of this ink, it is possible to apply a force to the return of the towing thread of the ink. In FIG. 16A, a piezoelectric element is used as the hydrostatic pressure generation means 27, and the pressure applied to the ink can be changed by changing the drive voltage thereof. FIG.
In (B), the hydrostatic pressure was applied to the ink 26 through the pipe using the hydrostatic pump 27a. Hydrostatic pump 27a
Is to generate hydrostatic pressure in the liquid, and an appropriate liquid such as water or oil is used as the liquid. If necessary, the liquid 27 can be prevented from being mixed with the ink 26 by providing the diaphragm 27b at the interface with the ink 26. The pressure applied to the ink can be changed by changing the drive energy applied to the hydrostatic pump 27a. As the hydrostatic pump, a device that can change the hydrostatic pressure applied to the liquid by the drive voltage, for example, an electrostrictive element, a magnetostrictive element, an electromagnet, or the like can be used as appropriate means.

FIG. 17 shows an embodiment using an air flow.
In front of the orifice plate 22, a cover plate 28a having a hole for sending out air is provided, and an air flow 28 is introduced between the orifice plate 22 and the cover plate 28a to flow outside from the hole of the cover plate 28a. By changing the flow velocity distribution of the air flow depending on the air flow rate and the cross-sectional shape of the hole, it is possible to apply a desired force to the string.

FIG. 18 shows an embodiment using a magnetic force generating means. When an ink containing a magnetic material is used as the ink 26, magnetic force can be used as a means for generating a force applied to the string. In this embodiment, as the magnetic force generating means 29, an electromagnet is arranged on the back electrode 24 side so as to exert a suction force on the ink. The attraction force applied to the ink can be changed by changing the current applied to the electromagnet.

It should be noted that the embodiments described with reference to FIGS. 16 to 18 may be combined to exert a force on the ink. In addition, by generating a towing thread of the ink and applying a force to fly the ink by the method described in FIGS. 16 to 18,
The ink may be given a flying force, and thereafter, the force may be gradually reduced. In that case, the electrostatic attraction force by the control electrode 21 and the back electrode 24 in FIGS.

[0055]

As is apparent from the above description, according to the ink jet recording method of the present invention, the ink can be ejected without being affected by the meniscus vibration at the time of the previous ink ejection, and therefore, the simple configuration is possible. Thus, there is an effect that variations in dot diameter of dots recorded on the recording medium and misdirection are reduced, and a good color image can be reproduced.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a color inkjet recording apparatus to which an inkjet recording method of the present invention is applied.

2 is a configuration diagram showing an example of recording heads 1 to 4 in FIG. 1, and FIG. 3 is an explanatory diagram of a printing state by the recording heads in FIG.

FIG. 3 is an explanatory diagram of a printing state by the recording head of FIG.

FIG. 4 is an explanatory diagram of an example of transfer fixing from the intermediate transfer member 5 to the recording medium 8.

FIG. 5 is an explanatory diagram of an electrostatic suction type inkjet recording method.

FIG. 6 is an explanatory diagram of an unstable state of the liquid surface after the pulse voltage is cut off.

FIG. 7 is an explanatory diagram of the operation of the present invention.

FIG. 8 is a specific example of the voltage waveform in the embodiment described in FIG. 7 (B).

FIG. 9 is an explanatory diagram of another example of the voltage waveform.

FIG. 10 is an explanatory diagram of another example of the voltage waveform.

FIG. 11 is an explanatory diagram of another example of the voltage waveform.

FIG. 12 is an explanatory diagram of another example of the voltage waveform.

FIG. 13 is an explanatory diagram of another example of the voltage waveform.

FIG. 14 is an explanatory diagram of another example of the voltage waveform.

FIG. 15 is an explanatory diagram of another example of the voltage waveform.

FIG. 16 is an explanatory diagram of a recording head according to another embodiment of the present invention.

FIG. 17 is an explanatory diagram of a recording head according to another embodiment of the present invention.

FIG. 18 is an explanatory diagram of a recording head according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Black recording head, 2 ... Yellow recording head, 3 ... Magenta recording head, 4 ... Cyan recording head, 5 ... Intermediate transfer body, 6 ... Intermediate transfer body heater, 7 ... Cleaner, 8 ... Recording medium , 9 ... Back roller, 9a ... Steel roll, 9b ... Resin layer, 10 ... Powder ink, 11 ... Molten ink, 12 ... Head heater, 13 ... Pixel drive board, 1
4 ... Control electrode, 15 ... Flexible substrate, 16 ... Orifice, 17a ... Ink string, 17b ... Ink dot,
18 ... Drum substrate of intermediate transfer body, 19 ... Surface layer of intermediate transfer body drum, 21 ... Control electrode, 22 ... Orifice plate, 2
3 ... Insulating protective layer, 24 ... Back electrode, 25 ... Recording medium,
26 ... Ink, 27 ... Hydrostatic pressure generating means, 27a ... Hydrostatic pressure pump, 27b ... Diaphragm, 28 ... Air flow, 28a ... Cover plate, 29 ... Magnetic force generating means.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuro Kodera 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Keizo Abe 2274, Hongo Ebina City, Kanagawa Prefecture (72) Fuji Xerox Co., Ltd. (72) Inventor Kazuo Maruyama 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.

Claims (2)

[Claims] 1. A recording head is filled with ink, the recording head has an ejection port for ejecting the ink, the ink is held so as to form a meniscus at the ejection port, and the ink is pulled from the recording head. In an inkjet recording method in which a yarn is generated and ink is ejected to perform recording, after the ink is ejected, a force is applied to the ink that opposes the return of the ink on which the towing yarn is formed to the ejection port. An inkjet recording method characterized by the above. 2. A recording head is filled with ink, the recording head has an ejection port for ejecting the ink, the ink is held so as to form a meniscus at the ejection port, and is arranged to face the recording head. In the inkjet recording method in which a potential difference is applied between the counter electrode and the counter electrode to cause the ink to fly and the ink is ejected to perform recording, the pulse voltage for ejecting the ink gradually decreases after the application of the maximum pulse voltage. The inkjet recording method is characterized in that