JPH04201345A - Liquid jet recording device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application 1] The present invention relates to a liquid jet recording device, and particularly to a liquid jet recording device having a multi-nozzle type liquid jet recording head.

[Conventional technology]

This type of liquid jet recording device is capable of high-speed printing and high-density recording with low noise, and because it does not require processing such as developing and fixing on plain paper, the device itself can be made smaller. It is also attracting particular attention as it has good productivity during mass production (manufacturing costs can also be kept low).

In particular, on-demand liquid ejecting devices have been viewed as promising applications because they do not require a high voltage generator and an unnecessary ink recovery device that are required in continuous liquid ejecting recording devices, and the devices can be miniaturized.

Among them, the type described in Japanese Patent Publication No. 61-59914 heats a part of the recording liquid in the liquid path to cause film boiling, thereby recording from a discharge port communicating with the liquid path. It is attracting the most attention as a liquid jet recording apparatus that ejects liquid to form flying droplets and makes the droplets adhere to a recording material for recording. Moreover, since the above-mentioned liquid jet recording head has the characteristic that it is easy to increase the density of the ejection ports and make them multiplied, it is possible to increase the recording speed and obtain high-quality images by increasing the length of the head.

By the way, when high-density recording is performed using a multi-nozzle type recording head as described above, when a flying droplet lands on a recording material, it deviates from the position where it should originally land.
In the following, this is called impact error. ) is known to affect image quality.

Originally, in order to improve image quality, it is necessary to create a liquid jet recording head that does not cause landing errors of flying droplets, but it is necessary to create a multi-nozzle liquid jet recording head that has these characteristics to maintain high yield. However, it is difficult to mass produce, resulting in expensive liquid jet recording heads and devices.

Therefore, in order to solve the above-mentioned problems, a liquid jet recording method was proposed in Japanese Patent Application Laid-open No. 62-22, which combines a multi-nozzle liquid jet recording head with static electricity generation means, as shown in FIG.
5353 and Japanese Patent Application Laid-Open No. 62-240559. In FIG. 5, lO is the liquid jet recording head main body, 1
1 is the multi-droplet ejection port, 12 is the counter electrode 1
This is a recording material held by 3. Now, when an image recording signal enters the recording head IO, a high potential difference of several thousand volts is formed between the recording head main body 10 and the counter electrode 13.
Droplets from the liquid ejection port 11 of the recording head IO reach the counter electrode 13
The ink is ejected and flies, and an image is recorded on the recording material 12. Thus, according to this method, high-speed, high-density recording, which is a feature of multi-nozzles, can be performed without landing errors and high-quality images can be obtained.

[Problem to be solved by the invention]

However, in the conventional example described above, droplets ejected from the ejection port 11 of the liquid jet recording head IO due to static electricity fly over the shortest distance between the recording head 10 and the recording material 12, and form an image on the recording material 12. Recording is performed, but in order to form droplets with no landing error (flying them and recording an image on the recording material 12), a high potential difference of several thousand volts is applied to the recording head 10.
and the recording material 12, which increases the power consumption and manufacturing cost of the apparatus, and makes it difficult to miniaturize the apparatus.

In order to solve these problems, the present invention enables mass production while maintaining a high yield, does not cause landing errors of flying droplets (high quality images can be obtained, is inexpensive, small, Another object of the present invention is to provide a liquid jet recording device that can reduce power consumption.

[Means to solve the problem]

In order to achieve such an object, the present invention provides a plurality of ejection ports for ejecting recording liquid, and an energy source disposed in a liquid path communicating with the ejection ports and used for ejecting the recording liquid. a liquid jet recording head having an energy generating element that generates energy, and a liquid jet recording head having a plurality of fine electrodes arranged in an array facing each of the ejection ports, and a substrate that holds the recording material at the position. A recording material holding member is provided, and a bias voltage is generated between the recording liquid discharged from the discharge port and the fine electrode arranged at a position opposite to the discharge port in accordance with a recording signal. It is characterized by

[For production]

According to the present invention, when the energy generating means is energized to eject the recording liquid from the ejection port, the fine electrodes disposed opposite the ejection port are also energized by simultaneous energization. A potential difference of, for example, only a few hundred volts is created by a bias voltage between the recording liquid that is about to be ejected from the ejection port and the fine electrode, so that the ejected droplet can fly toward the fine electrode. This eliminates landing errors and allows high-quality image recording to be achieved with less power consumption.

[Examples] Examples of the present invention will be described below in detail and specifically based on the drawings.

1 and 2 show one embodiment of the invention. In these figures, 1 is a liquid jet recording head, 2 is a liquid path, and 3 is a liquid jet recording head.
are electrothermal conversion elements (hereinafter referred to as discharge heaters) provided in each of the liquid paths 2; 4A and 4B are electrodes that supply recording signals to the discharge heaters 3; 5 is a liquid discharge port that opens at the tip of the liquid path 2; A conductive recording liquid 6 is supplied to the liquid path 2 from a recording liquid supply section (not shown). For such a liquid jet recording head 1, 7 is a holding member (hereinafter referred to as an electrode array head) that holds an array of fine electrodes 8 (hereinafter referred to as a fine electrode array) at a position facing the ejection surface of the recording head 1. be. Here, the arrangement spacing of the fine electrodes 8 is made to match the spacing of the liquid ejection ports 5 as shown in FIG. They are kept at a predetermined distance.

The above-mentioned fine electrode 8 is for forming a predetermined electrostatic field between the liquid ejection port 5 and the recording material 12, and in this example,
Settings were made so that a potential difference of about 500 volts was obtained between the recording liquid 6 guided to the liquid discharge port 5 and the microelectrode 8. In addition, with respect to the arrangement of the liquid jet recording head 1 and the electrode array head 7, the recording material 12 is sheet-fed in a direction perpendicular to the arrangement direction of the ejection ports 5 by, for example, a recording material feeding means (not shown). During this time, recording liquid is selectively discharged from the liquid discharge ports 5 in accordance with the timing of sheet feeding, and a recorded image is formed on the recording material 12.

Therefore, in this example, recording signal pulses corresponding to image formation are supplied to the discharge heater 3 provided in the liquid path 2, and at the same time, signal pulses are supplied to the fine electrode 8 located at the opposite position. As a result, bubbles 6A are generated in the recording liquid 6 in contact with the discharge heater, as shown in FIG.
At the same time that the liquid 6 is about to be ejected from the liquid ejection port 5, the ejected liquid is attracted to the opposing microelectrode 8 and becomes a flying droplet, which correctly lands on the recording material 12.

The present inventors conducted a comparative experiment to examine the landing error between a liquid jet recording device equipped with a microelectrode array according to the present invention and a conventional liquid jet recording device that does not have such an electrode, and the results are shown in Fig. 3. I got it. Note that the intersection point of the broken line indicates the determined correct landing position on the recording material.

As shown in FIG. 3, by using the fine electrode array head 7, it was possible to almost eliminate landing errors and obtain high-quality, high-quality recording. Further, since the above-mentioned effect can be obtained with a potential difference between the liquid path 2 of the liquid jet recording head 1 and the microelectrode 8 of the microelectrode array head 7 of several hundred volts, power consumption can be reduced. can, and
Accordingly, it becomes possible to downsize the device.

FIG. 4 shows another embodiment of the invention. In this example, the liquid discharge port 5
This is an example in which the present invention is applied to a recording head 100 having a hole formed at a position opposite to the ejection heater 3, and the ejection operation and effects are the same as those in the previous example, so a description thereof will be omitted.

As another embodiment of the present invention, an example will be shown below in which the position of the electrode relative to the ejection port is shifted by a predetermined amount from the position facing the ejection port shown in the above embodiment.

This is because in normal printing operations, the recording material is continuously conveyed while ink is ejected from the recording head, and in this case, it is more suitable for improving landing accuracy. . In other words, at the position where the ink droplet is expected to land on the recording material at the time of ejection 8, it takes a predetermined time from the time the ink is ejected until the ink lands, and during this time the recording material is transported. Therefore, the position is shifted by a predetermined amount from the position facing the ejection port. Therefore, if the fine electrodes shown in the above embodiments are provided in correspondence with the positions shifted by the predetermined amount, it is possible to cause the ink to land at the assumed impact position. At this time, if the ejection speed of the ink droplet is V, the conveyance speed of the recording material relative to the recording head is V, and the gap between the ejection port and the recording material is d, then the above deviation amount is 1×d
It can be expressed as:

Furthermore, when recording materials with various thicknesses are used, the gap d changes. Therefore, corresponding electrode positions can be considered. That is, for example, the thicker the recording material used, the smaller the gap d (becomes), and the smaller the amount of deviation (becomes).

Therefore, it is also possible to provide a configuration in which the position of the electrode relative to the ejection port is shifted depending on the thickness of the recording material.

If the configuration shown above in which the electrode position is shifted from the position facing the ejection port is not used, for example, when newly recording on recording paper, the recorded image as a whole will be shifted from the desired position. There is no problem. However, when recording later on a format paper on which ruled lines etc. have been recorded in advance or on a paper on which images have been recorded in advance, the above-described configuration can prevent images from overlapping.

Furthermore, in order to improve the landing accuracy, the size of the fine electrode can be made more suitable by taking into account the electric field and the like that will be formed. That is, it is preferable that the size of the microelectrode is approximately the same as the size of the ejection port. For example, when the size of the ejection port is 50 μm×50 μm, the size of the electrode is preferably in the range of 60 μm×60 μm to 30 μm×30 μm. Furthermore, since the shape of the ejected ink droplet is a so-called teardrop shape, its cross-sectional area is smaller than the cross-sectional area of the ejection port. Therefore, more preferably, the area of the fine electrode is smaller than the area of the ejection port, specifically 50
% is good. In addition, the electrode shape is preferably a circle or a regular polygon, similar to the cross-sectional shape of an ink droplet.

Furthermore, it goes without saying that the arrangement of the liquid paths and liquid discharge ports and the arrangement of the corresponding fine electrodes are not limited to the linear arrangement described above, but may be a staggered arrangement. Furthermore, the recording liquid discharge energy generating means is not limited to an electrothermal transducer or the like (it may also be a piezoelectric element, a mechanical means, or a combination of these).

(Others) In particular, the present invention is an inkjet recording method that includes a means (for example, an electrothermal converter, a laser beam, etc.) for generating thermal energy as energy used for ejecting ink, This provides excellent effects in recording heads and recording apparatuses that use energy to cause changes in the state of ink. This is because such a system can achieve higher recording density and higher definition.

As for typical configurations and principles thereof, it is preferable to use the basic principles disclosed in, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740,796. This method can be applied to both the so-called on-demand type and continuous type, but especially in the case of the on-demand type, it is necessary to arrange the liquid (ink) in accordance with the sheet and liquid path that hold it. The electrothermal converter that is
Generating thermal energy in the electrothermal transducer and producing film boiling on the thermally active surface of the recording head by applying at least one drive signal that corresponds to recorded information and provides a rapid temperature rise above nucleate boiling. This is effective because, as a result, bubbles in the liquid (ink) can be formed in pairs corresponding to the drive signals. The growth and contraction of this bubble causes the liquid (ink) to be ejected through the ejection opening to form a small droplet (at least one droplet).If this drive signal is in the form of a pulse, the growth and contraction of the bubble will occur immediately and appropriately. Because you will be exposed to
Particularly responsive liquid (ink) ejection can be achieved,
More preferred. This pulse-shaped drive signal is described in U.S. Pat. Nos. 4,463,359 and 4,345,262.
Those described in the specification are suitable. Furthermore, if the conditions described in US Pat. No. 4,313,124 concerning the invention regarding the temperature increase rate of the heat acting surface are adopted, even more excellent recording can be performed.

The configuration of the recording head includes, in addition to the combination configuration of ejection ports, liquid paths, and electrothermal converters (straight liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specifications, a heat acting section. The present invention also includes configurations using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose configurations in which the wafer is placed in a bending region. In addition, Japanese Patent Application Laid-Open No. 1989-5 discloses a configuration in which a common slit is used as a discharge part of a plurality of electrothermal converters.
No. 9-123670 and Japanese Patent Application Laid-Open No. 59/1989 which discloses a configuration in which a discharge portion is made to correspond to an opening that absorbs pressure waves of thermal energy.
The effects of the present invention are also effective even if the structure is based on the publication No.-138461. That is, regardless of the form of the recording head, according to the present invention, recording can be performed reliably and efficiently.

Furthermore, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium that can be recorded by a recording apparatus.

Such a recording head may have either a configuration in which the length is satisfied by a combination of a plurality of recording heads, or a configuration as a single recording head formed integrally.

In addition, even with the serial type shown above, the recording head is fixed to the device body, or by being attached to the device body, electrical connection to the device body and ink supply from the device body are possible. The present invention is also effective when using a replaceable chip type recording head or a cartridge type recording head in which an ink tank is integrally provided in the recording head itself.

Further, it is preferable to add recovery means for the recording head, preliminary auxiliary means, etc., which are provided as a configuration of the recording apparatus, to the present invention, because the effects of the present invention can be further stabilized. Specifically, these include capping means for the recording head, cleaning means, pressure or suction means, preheating means using an electrothermal transducer or another heating element, or a combination thereof; It is also effective to perform a preliminary ejection mode in which ejection is performed separately from printing in order to perform stable printing.

In addition, regarding the type and number of recording heads installed, for example, in addition to one type that corresponds to single-color ink, there is also a plurality of recording heads that correspond to multiple inks with different recording colors and densities. It may be something that can be done. In other words, for example, the recording mode of the recording device is not only a recording mode for only the mainstream color such as black (although the recording head may be configured integrally or by a combination of multiple heads, it can also be used for multiple colors of different colors). The present invention is also extremely effective for devices equipped with at least one of full colors, or mixed colors.

In addition, in the embodiments of the present invention not described above,
Although ink is described as a liquid, it is an ink that solidifies at room temperature or below, but softens or liquefies at room temperature, or in an inkjet method, the ink itself is
Generally, the temperature is adjusted within the range of 0°C or more and 70°C or less so that the viscosity of the ink is within the stable ejection range, so the ink becomes liquid when the recording signal is applied during use. That's fine. In addition, the temperature increase caused by thermal energy can be actively prevented by using it as energy for changing the state of the ink from a solid state to a liquid state, or
Alternatively, ink that solidifies when left unused is used to prevent ink evaporation, but in any case, the ink is liquefied by applying thermal energy in response to a recording signal, and the liquid ink is ejected, or the recording medium The present invention is also applicable to the case where an ink that is liquefied only by thermal energy is used, such as an ink that begins to solidify by the time it reaches . The ink for such cases is disclosed in Japanese Patent Application Laid-Open No. 54-56847 or Japanese Patent Application Laid-Open No. 60-7126.
As described in Japanese Patent No. 0, the porous sheet may be held as a liquid or solid in the recesses or through-holes of the porous sheet, facing the electrothermal converter. In the present invention, the most effective method for each of the above-mentioned inks is to implement the above-mentioned film boiling method.

In addition, the inkjet recording apparatus of the present invention can be used as an image output terminal for information processing equipment such as a computer, or as a copying apparatus combined with a reader or the like, or as a facsimile apparatus having a transmitting and receiving function. It may also be something that takes .

〔Effect of the invention〕

As described above, according to the present invention, a plurality of ejectors 80 for ejecting recording liquid and a liquid path communicating with the ejection ports are provided, and energy used for ejecting the recording liquid is provided. A recording material holding member having a plurality of fine electrodes arranged in an array facing each of the ejection ports is provided at a position opposite to the recording head having an energy generating element to generate energy. Since a bias voltage is generated between the element and the fine electrode facing it, the flying droplets ejected from the ejection port toward the recording material on the recording material holding member can be accurately directed. It can be made to land on the recording material, and high-quality, high-quality recording can be obtained.

Furthermore, according to the present invention, even if the flying direction of the droplets to be ejected deviates from the conventional normal direction, the electric potential difference generated between the recording liquid to be ejected and the fine electrodes allows By correcting the flight trajectory and landing the bullet on the recording material without any landing error, a high-quality recorded image can be obtained.
The yield rate can be increased for mass production, and it has become possible to provide an inexpensive and compact liquid jet recording device.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an example of the liquid jet recording device of the present invention. Fig. 2 is a cross-sectional view of Fig. 1. Fig. 3 is a diagram showing the results of a comparative experiment of the impact position according to the present invention. FIG. 5 is a cross-sectional view showing another embodiment of the present invention, and FIG. 5 is a cross-sectional view showing the configuration of a conventional example. 1.100...Liquid jet recording head, 2...Liquid path, 3...Discharge heater, 5...Discharge port, 6...Recording liquid, 7...Electrode array head, 8... - Microelectrode, 12... Recording material. Fig. 1 shows the structure of Fig. 11 (r) Fig. 2 shows the comparative experimental results of the present invention JS Gaga 5 landing hI Figure 4 Procedure Amendment (B1 March 25, 1991)

Claims (1)

[Scope of Claims] 1) A plurality of ejection ports for ejecting recording liquid, and energy disposed in a liquid path communicating with the ejection ports to generate energy used for ejecting the recording liquid. a liquid jet recording head having a generating element; and a recording material holding member having a plurality of fine electrodes arranged in an array facing each of the ejection ports and holding the recording material at the position. A bias voltage is generated in response to a recording signal between the recording liquid discharged from the discharge port and the fine electrode disposed opposite the discharge port. A liquid jet recording device. 2) The energy generating element of the liquid jet recording head and the fine electrodes disposed at opposing positions of the ejection opening of the liquid path in which the energy generating element is disposed are simultaneously energized by the recording signal. The liquid jet recording device according to claim 1. 3) The liquid jet recording apparatus according to claim 1 or 2, wherein the energy generating element is an electrothermal converter that generates heat when energized.