JPS6242848A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To permit recording to be performed by ink flying with good selectivity even in case where the resistance and viscosity of ink are low or the applying environment is of high humidity, by covering the surface of the opposite electrode with an insulating film. CONSTITUTION:A heat-shrink polyester resin film 21 uniformly covers the surface of a roller-type opposite electrode 8 in a thermally shrunk manner. The thickness of the resin film 21 is 1-100mum. Using the roller type opposite electrode 8 coated with the polyester film, photo-ON-OFF operation is made on the photo-conductive film to obtain an electric signal by the photo-electric conversion, and ink 5 is selectively flown by the electric signal. Hereupon, the implantation of charge from the electrode 8 can be prevented, and sharp recording corresponding to the photo-ON-OFF operation can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an inksheet type recording device provided in, for example, a printer or a facsimile machine.

[Technical background of the invention and its problems]

Inkjet recording devices are currently used in printers and facsimile machines as plain paper recording devices that do not require a fixing operation, but electronic flat scanning is desired to improve high-speed recording performance and simplicity. . This electronic plane scanning has been studied mainly by using multiple nozzles, but at present it has not been put into practical use due to the problem of reduced reliability due to ink clogging of each recording nozzle.

Therefore, the following slit-jet method has been proposed as a plane scanning ink-jet method that does not have the disadvantages of the nozzle method.

That is, FIGS. 4 and 5 show diagrams of the principle of the slit jet recording method already proposed by the present inventors.

In the figure, reference numeral 1 denotes an insulating substrate. On this substrate 1, there are a plurality of individual electrodes 31° 3b patterned with, for example, 8/= or 16/■, and the individual electrodes 3m, 3b have a predetermined gap fa. , and face each other one-on-one.

For example, amorphous selenium (hereinafter referred to as 1a-8) or amorphous silicon (hereinafter referred to as a-81) is used between the shirts 163.
It is written as ) A photoconductive film 18 is deposited. Further, the individual electrodes 3b are electrically connected to the first common electrode 14.

Also, there is a minute gap d between the lower recording head section and the above.

An upper recording head section 2 is provided having a second common electrode 4 spaced apart by . The tip of the recording head section 12 is opened in the shape of a slit with a small slit gap. In addition, a roller-shaped counter electrode 8 is provided opposite to the recording head section 12 by a minute gap d, and a recording medium 11 such as plain paper is provided between the recording head section 12 and the counter electrode 8. It has become.

Ink 5 is supplied from the ink storage container 13 to the tip of the recording head 12. Further, above the photoconductive film 18, there are a lens array 17, a light source 15, and a document table 16.
6 moves in the direction of the arrow, the optical image of the document passes through the lens array 17 and is irradiated onto the photoconductive layer 18.

Next, the recording principle of the slit jet recording method will be explained. The document table 16 and the recording medium I are operated synchronously by turning on the switch, the light source 15 is turned on, and the optical image of the document is irradiated onto the photoconductor film 18 through the fiber lens array 17.

For example, a DC power source 6 of θ is connected to the first common electrode 14, and a DC power source 7 of ■ is connected to the second common electrode 4. The potential of O is applied to the tip 3c of the recording head, and the potential of ■ is applied to the dark area.
The potential of is output.

The principle of the above signal output will be explained using the equivalent circuit shown in FIG. That is, the resistance of photoconductor 1 [18 when irradiated with light is ρp
h, the resistance in the dark is ρpark, and the resistance of the ink between the second common electrode 4 and the recording electrode 3 is 6'=ρINK,
Since the ink resistance ρlN1C is adjusted so that the relationship ρph<ρweight NK<ρD□ holds, ρlNK becomes dominant during light irradiation, and a potential of θ is outputted to the recording electrode tip 3C by the power source 6. When it is dark, ρDark becomes dominant, and the power supply 7 outputs a potential of 2.

Next, a pulse-like voltage is applied to the roller-shaped counter electrode 8 on the O side with respect to 0■, and when the potential of ■ is output to the recording electrode tip 3C described above, the ink meniscus 12 is
The principle is that the ink 5 is injected, and the ink 5 flies toward the counter electrode 8, thereby enabling selective recording on the recording medium 11 corresponding to the original image.

As a result of studies by the present inventors, it has been found that recording by ink flying can be performed satisfactorily under the process setting conditions shown below. That is, the applied voltage of the first common room &4; ■50 to ■1kV the second
Applied voltage to the common electrode 14: 0 to 1 kV Applied voltage to the roller-shaped counter electrode 8: 0 to θ2. OkV Frequency: 10 to 10 kHz Gear, d110 μm to 500 μm Gear y7'dllO μm to 300 μm The value of Gap 7°d1 varies depending on the resistivity of the photoconductor film 18, but for example, if the photoconductor film 18 is an a-81 film In the case of 20 firr~80 μmm-Be.

In the case of a-8@T., it is 5 μm to 50 μm.

If the photoconductor film 18 is, for example, a-8i1, ρD
ark is 10~10Ω, ρpbat is 10~108Ω
Since it is a country, ink resistance 5' = ρINK is 10' to 1
I have to choose 010Ωtan.

Of the light image irradiated onto the photoconductor film 18, there are 50 bright areas.
Lux ~500 LuX.

However, it has been found that the above-mentioned slit jet recording method has the following drawbacks.

That is, when the resistance of the ink 5 is as low as 1070 steel or less, and when the viscosity of the ink 5 is low, as shown in FIGS. A charge of ■ is injected from the electrode 8, and the charge of the ink 5, which is originally ■, is reversed to θ, and even when the electric signal at the end of the recording electrode 3a is turned off, the 5 ink drops are not cut off and the ink 5 is recorded. The end of the electrode 31 and the roller-shaped back electrode 8 are connected.

Furthermore, even if the ink resistance is as high as 107Ωm or more, the resistance of the recording medium 11 such as plain paper decreases to less than 1090Ω when the humidity is 85Ω or higher, so the same phenomenon occurs. The matter was confirmed.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to:
Another object of the present invention is to provide an inkjet recording apparatus that can perform recording by selectively ejecting ink even when the environment in which it is used is humid at 85% or higher.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention covers the surface of the counter electrode with an insulating film, thereby preventing injection of ◯ charges into the jetted ink.

[Embodiments of the invention]

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

Note that the same parts as those shown in FIG. 2 are given the same numbers, and the explanation thereof will be omitted. In the figure, reference numeral 21 denotes a resin as an insulating film overcoated on the surface of the roller-shaped counter electrode 8. The film thickness of this resin 21 is 1 μm to 1100 μm.
It is said to be 1t.

Note that if the film thickness of the resin 21 is less than 1 μm, there will be problems with the insulation itself or pinholes, and if it is more than 100 μm, the capacitance will increase and the roller-shaped counter electrode 8
The frequency response of the pulsed DC voltage becomes slow due to the time constant CR.

Therefore, the film thickness of the resin 21 is preferably 5 μm or more.
Less than μm is better.

The resin 21 was a heat-shrinkable polyester film that was heat-shrinked over the surface of the roller-shaped counter electrode 80 to uniformly coat it. The thickness of the film on the surface of the roller-shaped counter electrode 8 at this time is about 20 μm.

Light is turned on and off on the photoconductive film 18 using the roller-shaped counter electrode 8 coated with the above-mentioned polyester film with a thickness of 2 μm, and the photoelectrically converted electric signal is used to ink 5 (steel with resistance of 105Ω, viscosity of 7.5 μm). When a selective flight experiment was carried out using the method 3/As), charge injection from the counter electrode 8 was prevented, and sharp recording corresponding to light ON/OFF could be performed.

In addition, using ink 5 with a resistance of 10 Qcm and a viscosity of 14.5 poise, an original image was recorded using a Surin)-/Et recording apparatus having the configuration shown in FIGS. 2 and 3 under high humidity of 85 cm. When we performed so-called copying, we were able to record clear images with good resolution.

〔Effect of the invention〕

As explained above, since the surface of the counter electrode is coated with an insulating film, the present invention prevents charge from being injected from the counter electrode into the flying ink, and it is possible to use ink with low resistance and low viscosity. Moreover, even in humid conditions of 85% or more, recording can be performed by selectively ejecting ink droplets with good sharpness in response to light on/off signals.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a part of a recording device that is an embodiment of the present invention, FIGS. 2 to 6 show a conventional example, and FIG. 2 is a schematic configuration diagram showing a recording device. 3 is a plan view showing the electrode section, FIG. 4 is an equivalent circuit diagram showing signal output to the electrode section, and FIG. 5 is a survey diagram showing ink continuous between the recording electrode end and the roller-shaped counter electrode. FIG. 6 is a plan view thereof. 3... Individual electrode, 8... Counter electrode, 11... Recorded object, 5... Ink, 21... Resin (insulating film).

Claims (2)

[Claims] (1) In an apparatus that records information by spraying ink onto a recording medium supported by a counter electrode by selectively applying a voltage to a plurality of individual electrodes according to recording information, the An inkjet recording device characterized in that the surface of an electrode is coated with an insulating film. (2) The inkjet recording apparatus according to claim 1, wherein the insulating film has a thickness of 1 μm to 100 μm.