JPS59138472A - Liquid jet recording apparatus - Google Patents

Abstract

PURPOSE:To obtain a liquid jet recording apparatus of which the frequency limit in the formation of liquid droplets is not lowered even if the simaltaneous driving of all nozzles is performed, by specifying length from the end surface which is present at the center of a liquid flowline in the width direction thereof and in the side of a common liquid chamber to the center of a liquid supply orifice. CONSTITUTION:The longest distance from the center of one liquid supply orifice 102 to a liquid flowline (the longest distance to the center line to the width direction in the common liquid chamber end surface of the liquid flowline) is set to (l). When the adjacent liquid supply orifice 102 is present in the other place, the longest distance indicates the longest one among the distances to the liquid flowline each of which is shorter the distance from the center of the other liquid supply orifice to the liquid flowline. The liquid flowline indicates the part held between side walls 103 communicated with each emitting orifice. When the center line of the emitting orifice 101 from the end surface of the common liquid chamber side of the liquid flowline is set to ln, the height of the common liquid chamber to hc and the height of the liquid flowline to hn, the liquid supply orifice is provided so as to satisfy the formula l<=100X(hc/hn)<3>X ln. In order to more effectively achieve the object, (e) is desirably adjusted so as to form the formula l<=20.A.ln[A=(hc/hn)<3>], optimumly. l<=4.A.ln.

Description

[Detailed description of the invention] The present invention relates to a liquid jet recording device.

Non-impact recording methods have recently attracted attention because the noise generated during recording is so small that it can be ignored. Among them, high-speed recording is possible,
However, the so-called inkjet recording method (liquid jet recording method), which allows recording on plain paper without the need for special processing such as fixing, is an extremely powerful recording method, and various methods have been devised so far. Some have been improved and commercialized, while others are still being worked on to put them into practical use.

In this liquid jet recording method, recording is performed by causing droplets of a recording liquid called so-called ink to fly and adhere to a recording member, and the generation of droplets of the recording liquid is There are several types of methods depending on the control method used to control the flying direction of the generated droplets.

Among them, the so-called drop-and-amand recording method, in which droplets are ejected from an ejection orifice in response to a recording signal and recorded by adhering the droplets to the surface of a recording member, is a method in which only the droplets necessary for recording are used. Since it does not eject, there is no need to provide special means for collecting or processing ejected liquid that is unnecessary for recording, and the device itself can be simplified and downsized, and the flying direction of droplets ejected from the ejection orimeter can be controlled. Recently, it has been attracting particular attention because it does not require color printing and multicolor recording can be easily performed.

Also, in recent years, diop-on-demand
Full jine type high-density multi-orifice recording head using a recording method (liquid jet recording head)
Development has also been remarkable, and many liquid jet recording devices have been developed that can obtain higher resolution and higher quality images at higher speeds.

In the liquid jet recording method using the drop-on-demand recording method as described above, pressure energy (mechanical energy) or thermal energy is applied to the liquid in the energy application section to create a driving force for ejecting droplets. I am getting . Therefore, it is necessary to act on the liquid so that these energies are efficiently consumed for ejecting droplets.

Furthermore, when recording is performed continuously, the generation of energy needs to occur repeatedly in reliable response to the recording signal. Particularly in the case of high-speed recording, it is necessary that this repetition be performed faithfully to the recording signal applied to the energy application section.

Alternatively, in order to improve the quality of recorded images and enable high-speed recording, it is necessary to stabilize the ejection direction of droplets and prevent the generation of satellites, and to stably and continuously print them for a long time. It is necessary to perform repeated droplet ejection and to improve the droplet formation frequency (the number of droplets formed per unit time).

Hyakunen et al., when the recording head is a full jine type and is made longer, the liquid consumed by ejecting droplets is not immediately replenished, and in particular, the ejection orifice far from the liquid supply hole is not sufficiently refilled. There was a problem that the liquid droplet discharge unit (nozzle) arranged in a multi-lined manner could not be uniformly supplied with enough lid liquid, so when all the nozzles were driven at the same time. The problem arises that the droplet formation frequency limit is lowered.

This fact impairs the advantage of the liquid jet recording method that images can be recorded at high speed, and is a problem when multiple recording heads are used.

The present invention was created in view of the above problems, and it is possible to supply a sufficient amount of liquid into each nozzle arranged in a multi-line manner, and even if all nozzles are driven simultaneously, there is a limit to the droplet formation frequency. An object of the present invention is to provide a liquid jet recording device that does not cause a drop in performance.

In order to achieve the above object, the inventors of the present application have made a sincere study and determined that the length/n from the center of the discharge orifice to the end face of the liquid flow path on the common liquid chamber side, and the widthwise center of the liquid flow path. In addition, an important relationship was found between the length 11 of the liquid flow path from the end face on the common liquid chamber side to the center of the liquid supply hole for supplying liquid to the common liquid chamber, the height hn of the liquid flow path, and the height heO of the common liquid chamber. Ta.

That is, the liquid jet recording device of the present invention that achieves the above object includes a liquid ejection port (discharge orifice) that forms flying droplets;
In a liquid jet recording device having a liquid flow path communicating with the liquid ejection port, a common liquid chamber communicating with the liquid flow path, and a liquid supply hole for supplying liquid (ink) to the common liquid chamber, l ≦100X (he/hn)”X/n --
The liquid supply hole is characterized in that the liquid supply hole is provided so as to satisfy equation (1).

Further, it is necessary to make the present invention more effective.

Hereinafter, the present invention will be explained using figures.

The lengths of the parts e, /n, he, and hn described above are specifically explained using the schematic plan view shown in FIG. 1 181 and the schematic cross-sectional view shown in FIG. 1 181. explain. FIG. 1 181 is a diagram cut along the dashed line xx' shown in FIG. 1 181.

In both figures, 101 is a discharge orifice, 102 is a liquid supply hole, and 103 is a side wall.

As shown in the figure, l is the longest distance in the liquid flow path 1 from the center of one liquid supply hole 102 (the longest distance from the center line in the width direction of the common liquid chamber end face of the liquid flow path) It is. If there are other adjacent liquid supply holes 102 (if there are multiple liquid supply holes 102), the distance to the liquid flow path that is less than or equal to the distance from the center of the other liquid supply hole to the liquid flow path. Indicates the longest part. /n is the length from the end surface of the liquid flow path on the common liquid chamber side to the center line of the discharge orifice 101, he is the height of the common liquid chamber, and hn is the height of the liquid flow path.

Furthermore, what is shown in Fig. 1 ta+ and Fig. 1 +bl is as follows.
Each of these shows one suitable recording head, and it goes without saying that the actual recording head will not take exactly the same form, but the parts indicated by e, /n, he, hn, etc. Indicate the length of the part as shown.

2 to 4 are diagrams for explaining a preferred first embodiment of the present invention, respectively, and FIG. 2 is a schematic perspective assembly view, and FIG.
The figure is a schematic plan view, and FIG. 4 is a schematic sectional view taken along the dashed line Y-Y' shown in FIG. 3. Second
In the figures to FIG. 4, 201 and 2 are discharge orifices, respectively.
02 is a liquid supply hole, 203 is a side wall, 204 is an orifice plate provided with the discharge orifice 201, and 205 is a second
common liquid chamber, 206 is a protective layer, 207 is an electrode layer, 208
209 is a heat generating resistance layer, 209 is a substrate, and 210 is an external wiring. (In addition, the discharge orifice 201 in FIG. 3 shows the position of an imaginary discharge orifice.) In this embodiment, as shown in the figure, the liquid supplied to the second common liquid chamber is The liquid is supplied from the supply hole 202 to the common liquid chamber, and the liquid is discharged from the discharge orifice 201 through the liquid flow path using thermal energy in accordance with an input signal.

Here, hn=hc=50μm, ln=1m1lr
32 discharge orifices 20 with a density of 8 per Jll (hereinafter referred to as 8/1jlII).
The recording head was manufactured in such a manner that the diameter of the ejection orifice 201 was 40 μm, the diameter of the 'M supply hole 202 was 200 μm, and /=4.

A liquid jet recording device having such a recording head is equipped with an applied voltage of 25 V (heater size for applying thermal energy to the liquid: 30 μm x 50 μm) + pulse width of 10 μsec,
Droplets were ejected under driving conditions of a frequency of 0.5 to 10 KH2 (variable).

As a result, the droplet formation frequency limit remained unchanged at 7 KHz even when droplets were ejected from only one ejection orifice and when droplets were ejected simultaneously from all 32 ejection orifices.

Furthermore, there was no difference in the ejection characteristics of the droplets ejected from the ejection orifice in any part of the recording head.

In this embodiment, which satisfies the conditions of the present invention, there was no difference in the droplet ejection state regardless of the position of the recording head (regardless of the difference in distance from the liquid supply hole). .

As a second embodiment of the present invention, a liquid jet recording apparatus using a recording head having a schematic cross-sectional view shown in FIG. 5 will be described. The numbers of the leader lines shown in the figures are the same as the respective numbers shown in FIGS. 2 and 3. This embodiment is different from the first embodiment in that he and hn are not equal. The droplet ejection means and liquid supply were carried out in exactly the same manner as in the first case. In this embodiment, the dimensions of each part are hn=50 μm.

he=100 μm, /n==111. The hole diameter of the discharge orifice 201 is 30 μm, and the hole diameter of the liquid supply hole is 200 μm.
, l=1011 m. Further, 64 discharge orifices 201 were arranged at a density of 12/II.

A liquid jet recording apparatus having a recording head manufactured as described above was driven under the same driving conditions as in the first embodiment. As a result, in this embodiment as well, droplets were ejected satisfactorily.

The droplet formation frequency limit and the liquid supply hole of the ejection orifice when the position of the liquid supply hole is changed, that is, when l is changed, in the heads of the first and second embodiment examples that are tilted upward. Table 1 shows differences in droplet ejection characteristics and overall evaluation due to differences in distance from the droplet.

◎: 4&Good, Q: Good, △: Fair, ×: Bad In the first embodiment, 256 discharge orifices were arranged at a density of 8 pieces/xx, hc=hn=50 μn.

I! n = 141111, l = 2 am, the diameter of the discharge orifice is 40 μm, and the diameter of the liquid supply hole is 2.
00μm, and the liquid supply hole is 6! A recording head with four recording heads arranged at intervals of III was manufactured.

When a liquid jet recording apparatus having the above-mentioned recording head was driven under the same conditions as in the first embodiment, very good droplet ejection characteristics were obtained as in the first embodiment.

In the embodiments described above, an example is shown in which the ejection energy of droplets is provided by thermal energy provided by a heat generating resistor layer which is an electrothermal converter, but the ejection energy is
In addition to thermal energy, for example, mechanical energy such as a piezo element, which is an electromechanical converter, may be used. The droplet ejection means may be any method as long as it is a means for ejecting droplets from the ejection orifice in response to an input signal.

Furthermore, in the present invention, an orifice is not provided at the end of the liquid flow path, and the structure is shown in which the liquid flow path is bent and the droplets are ejected. It is also possible to have an orifice provided therein.

It goes without saying that in the present invention, the discharge orifice is provided in a plate-shaped member, but the discharge orifice does not need to be provided in the plate-shaped member at all, and may be changed depending on ease of manufacture or other circumstances. It can be set within a range that satisfies the optimum conditions.

Although it is not necessary to separately provide a second common liquid chamber, if the arrangement density of liquid supply holes is increased, many liquid supply pipes etc. connected to the liquid supply holes will be required, making it difficult to manufacture a liquid jet recording device. Therefore, when increasing the arrangement density of liquid supply holes, it is preferable to provide a second common liquid chamber and connect the liquid supply pipe etc. to it. A liquid jet recording device that satisfies the conditions of the invention has a high droplet formation frequency limit and does not cause any difference in the ejection characteristics of droplets ejected from each ejection orifice. Since there is no difference in ejection characteristics, it is possible to improve the accuracy with which droplets ejected from each ejection orifice land on the recording member.

Therefore, according to the present invention, it is possible to obtain a very useful liquid jet recording device that can record better images at higher speeds.

[Brief explanation of drawings]

Figure 1 (1) and Figure 1 1b+ are l and I!, respectively. n,
111 is a schematic plan view, and FIG. 1 1b+ is a schematic cross-sectional view taken along the dashed line shown in FIG. 1 111. 2 to 5 are diagrams for explaining embodiments of the present invention, respectively, in which FIG. 2 is a schematic perspective assembled view, FIG. 3 is a schematic plan view, and FIG.
FIG. 5 is a schematic cross-sectional view taken along the dashed line shown in the figure, and FIG. 5 is a schematic cross-sectional view when the common liquid chamber is modified. 101, 201...discharge oriswiss, 102, 20
2...Liquid supply hole, 103, 203...Side wall, 20
4... Orifice plate, 205... Second common liquid chamber,
206... Protective layer, 207... Electrode layer 1.208.
...Heating resistance layer, 209...Substrate, 210...External wiring. 2 male figures

Claims (1)

[Claims] A liquid discharge port for forming flying droplets, a liquid flow path communicating with the liquid flow path, a common liquid chamber communicating with the liquid flow path, and a liquid discharge port for supplying liquid to the common liquid chamber. A liquid jet recording device having a liquid supply hole, characterized in that the liquid supply hole is provided so as to satisfy l≦100×(he/hn)”×l!n. 〇In the above, l... Length from the end face of the liquid flow path on the common liquid chamber side to the center of the liquid supply hole I!n... From the center of the discharge orifice to the end face of the liquid flow path on the common liquid chamber side Length hn...Height of liquid flow path he...Height of common liquid chamber