JPS6213379A - Ink jet recording method - Google Patents

Abstract

PURPOSE:To enable stable recording to be performed irrespective of resistance of a liquid ink, by a method wherein a pulse of voltage having negative polarity based on 0V as reference and a specified pulse width ratio is impressed on a counter electrode opposed to a recording electrode. CONSTITUTION:A pulse of voltage having negative polarity with based on 0V and a pulse width ratio of 2/5-3/5 is impressed on the counter electrode opposed to the recording electrode. The figure shows the pulse width of a pulse form DC potential impressed on a roller form back electrode 7 provided as the counter electrode. For example, where the resistance of the ink is as low as 10<6>-10<7>OMEGAcm, the ink 9 is selectively driven to fly when the pulse width ratio l/n is less than 3/5 (preferably, 1/20-1/2), and where the resistance of the ink is as high as 10<10>-10<11>OMEGAcm, the ink 9 is efficiently driven to fly when the pulse width ratio is more than 3/5 (preferably, 1/2-1). Namely, when the pulse width ratio l/n is 2/3-3/5 (optimally, 1/2), favorable ink jet recording through selective flying of the ink can be performed irrespective of the resistance of the ink.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention includes, for example! It relates to recording devices used in linters, facsimiles, etc.

[Technical background of the invention and its problems]

As for this type of recording device, the inkjet recording method is conventionally known as a plain paper recording method that does not require developing or fixing operations, but electronic flat scanning has been adopted to improve high-speed recording performance and simplicity. desired.

However, converting the inkjet recording system to electronic plane scanning has mainly been studied by using multiple nozzles, but in this case, the problem of reduced reliability due to ink smudges in each recording nozzle has prevented its practical use. The current situation is that this is not the case.

On the other hand, electrophotographic methods such as xerography require at least a drum-shaped photoreceptor and a charger, developer, transfer device, purifier, and static eliminator arranged around it, making it more compact. Currently, there are limits to how low prices can be reduced.

Therefore, as a planar scanning inkjet system that does not have the disadvantages of the nozzle system, a slit noette system as shown in FIGS. 2 to 5 has been proposed. That is, in the figure, 1a is an insulating substrate constituting the lower recording head A, and on this substrate la there are, for example, 8 or 1 recording head.
Multiple settered individual electrodes 2a with 6 pieces...
. , 2b . . . are provided. The individual electrode 2a.
..., 2b... are one-to-one via a predetermined gear lug d3.
A photoconductive film 3 of, for example, amorphous selenium (hereinafter referred to as a-8e) or amorphous silicon (hereinafter referred to as a-8i) is deposited between the gaps fd3. Further, a first common electrode 4 is electrically connected to the individual electrodes 2b.

Further, an upper recording head section B having a second common electrode 5 is provided on the substrate 1b with a slight distance d2 from the lower recording head section A having the above structure. A slit-shaped opening 6 is formed at the tip of the recording head H consisting of the lower and upper recording head portions A1B, and a roller-shaped counter electrode is formed at a slight distance d from the recording head H. 7
is provided, and a recording medium 8 such as plain paper is interposed between the recording head H and the counter electrode 7.

Also, No. 0 is an ink storage container, and this ink storage container 1
Ink 9 is supplied from 0 to the tip opening 6 of the recording head H.

Further, above the photoconductive film 3, a lens array 11, a light source 12, and a document table 13 are arranged, and as the document table 13 moves in the direction of the arrow, the optical image of the document passes through the lens array 11. The photoconductive film 3 is irradiated with light.

Next, the recording principle of this slit soet recording method will be explained.

The original platen 13 and the recording medium 8 operate in synchronization with the switch ON, the light beam 12 lights up, and the optical image of the original is irradiated onto the photoconductor film 3 through the fiber lens array 11.

For example, a direct current (e) is connected to the lower common electrode 4, a direct current voltage (3) is connected to the upper common electrode 5, and the recording electrodes 2a, which are irradiated with light, are connected to the recording head H A potential e is output to the tip of the image, and a potential ■ is output to the dark area.

The principle of the above signal output is explained using the equivalent circuit shown in FIG. That is, the resistance of the photoconductor film 3 when irradiated with light is ρ
The resistance in the dark is ρI) ar, both on the upper side ph The resistance ρ of the ink 9 between the communication electrode 5 and the recording electrode 2a...
1NK, the ink resistance ρINK is adjusted so that the relationship ρph <pINy<ρDark holds true, so ρINK is dominant during light irradiation, and the electric potential of the source e is applied to the recording electrodes 2a and 2a by the power supply 15. .

Next, a pulsed voltage is applied to the e side of 0 V to the roller-shaped back electrode 7, and when a potential of ■ is output to the tip of the recording electrode 2a, the ink menicus 9a is
This is the principle in which the ink 9 is injected and flies toward the back electrode 7, and selective recording can be performed on the recording medium 8 in accordance with the original image.

As a result of studies by the present inventors, it has been found that sufficiently good recording by ink flying is possible under the following setting conditions. That is, the voltage applied to the lower common electrode 4 e50 V-el kV The voltage applied to the upper common electrode 5 O~■1 kV The voltage applied to the roller-shaped surface electrode 7 0-02. OkV frequency
10~10kHz gear, 7'
dt loam~500μm, d, 10μm~300
The value of 1Jrn gap fd3 varies depending on the specific resistance of the photoconductor film 3, but for example, when the photoconductor film 3 is an a-5t film, the value is 20 μm to 80 μmXa-8s, a-
In the case of 3eTe, the thickness is 5 μm to 50 μm.

When the photoconductor film 3 is, for example, an a-8i film, ρDark
is io9~1012Qyn, ρ, 5゜゜105~108
Since it is a Ω port, ink resistance = ρ1NKFi, lO6~
Must be selected as 1010Ω.

Of the light image irradiated onto the photoconductor film 3, the bright area is 50 L.
It is ux ~ 500 Lux.

However, according to the studies of the present inventors, when the ink resistance = ρINK is as low as 10 to 10'Ω, as shown in FIG.
A problem occurred in that the signal of the glass leaked to the edge of the recording electrode 2a corresponding to the A area, which was entirely irradiated with light from other areas, causing the ink 9 to fly and causing so-called fog.

10m Also, if the ink resistance is as high as 10 to 10,
There also occurred a problem that the injection of charge from the ends of the recording electrodes 2 to the ink meniscus 9a was small, making it difficult for the ink 9 to fly.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to provide an in/out printing method that allows stable recording without being affected by the level of resistance of liquid ink. It is something.

[Summary of the invention]

In order to achieve the above object, the present invention applies a unipolar pulse voltage t to a counter electrode facing a recording electrode with reference to 0V.
- By applying the pulse width at a pulse width ratio of 215 to 315, electric charges can be injected into the ink menicus without leaking electrical signals to the recording electrodes.

[Embodiments of the invention]

The present invention will be explained below with reference to an embodiment shown in FIG.

FIG. 1 shows the nozzle width of a slightly lasing direct current potential applied to the roller-shaped back electrode 7 as a counter electrode.

As a result of the inventors' studies, for example, the ink resistance is 10 to
If the pulse width ratio J/n is as low as 10 Ω, the smaller the pulse width ratio J/n is than 315 (preferably 1/20 to 1/2), the ink 9 will be selectively ejected, and the ink resistance will be 10 Ω. ~10Ω
It has been found that the ink 9 flies more efficiently when the Solus width ratio is larger than 215 (more preferably 1/2 to 1).

In other words, when the pulse width ratio νn is 215 to 315 (optimally 1/2), good slit jet recording is possible due to selective ink flight regardless of the level of ink resistance. discovered.

This depends on the pulse frequency, but if the frequency is 10
It was found that the above tendency was even stronger in the range of 0 to 1 kHz, indicating that the pulse width of the present invention was effective.

[Example 1] Using ink with a resistance of 100 m, turn on the light only in the B region, which is the same as shown in Figure 5, under the Zorothe setting conditions shown below.
, OFF, and area A was irradiated over the entire surface to conduct a selective ink flight experiment.

Applied voltage of lower common electrode 4 -250v Upper common electrode 5
Applied voltage +250V Applied voltage of roller-shaped back electrode 7 -5oov Frequency 1 kHz Gear y f dt 150μ, dz IQQμm
, ds 40 μm photoconductor film 3 is a-8I B /'D10Ωα, ρ, , which is obtained by glow discharge decomposition of silane gas.
-10Ω photoconductor film surface photoconductor film surface height 100 Lu
No J in x? The l/n width ratio was varied from 0 to 1.

[Example 2] The pulse width ratio was set to 0/n under the same conditions as [Example 1] except that the ink resistance was set to 100.
It was varied by ~1.

Using the low-resistance and high-resistance inks of [Example 1] and [Example 2], the pull r+ shown in [Example 1] was set to 74' pulse width ratio 1/2 under 7 conditions. However, when we conducted an image reproduction experiment using a pick-and-jet recording device with the configuration shown in Figure 2, we were able to obtain copied images with no practical problems, although there was some fogging with the low-resistance ink. Ta. Regarding the high-resistance ink, although the overall density was slightly faded, a passable copy image was obtained.

〔Effect of the invention〕

As explained above, the present invention applies a unipolar pulse voltage to the counter electrode facing the recording electrode with Ov as a reference.
Since the ink was applied at a master pulse width ratio of 215 to 315, it is possible to stably record without being affected by the resistance level of the liquid ink.

[Brief explanation of drawings]

Fig. 1 is a graph showing the Nords voltage applied to the counter electrode according to an embodiment of the present invention, Figs. 2 to 5 show conventional examples, and Fig. 2 is a schematic diagram showing a recording device. configuration diagram,
Figure 3 is a plan view showing the electrode, Figure 4 is an electric circuit diagram, Figure 5
The figure is an explanatory diagram showing the flying state of ink. H... Recording head, 21L... Recording electrode, 7
. . . Counter electrode, 8 . . . Recorded object.

Claims (3)

[Claims] (1) A recording head having an opening at its tip, a recording electrode provided at the opening at the tip of the recording head, a counter electrode that faces the recording electrode and supports a recording object, and a recording electrode that supports the recording object. and an ink supply section that supplies liquid ink, and in the method of recording by causing the liquid ink to fly onto a recording medium in response to an electric signal output to the recording electrode, 0V is applied to the counter electrode. An inkjet recording method characterized by applying a pulse voltage of either positive or negative polarity as a reference. (2) An inkjet recording method characterized in that the pulse voltage has a pulse width ratio of 2/5 to 3/5. (3) The inkjet recording method according to claim 1, wherein the frequency of the pulse voltage is 100 Hz or more.