DE1923307A1 - Electrostatic charging process - Google Patents

Description

PENSION LAWYERS
8 MUNICH 2. HILBLESTHASSE 2O

Dr. Berj Dipl.-Inj. Stapf, 8 M flnchen 2, H ilbleslraOa 23 · Your mark "-" Our mark date

vii / Gd 18 4'io, 7, May 1969

Lawyer file no. 18 430

KABUSHIKI iiCAISHA RICOH, Tokyo / Japan.

Electrostatic charging process.

The invention relates to an electrostatic charging method and, more particularly, to a method for use in electrophotography to produce a electric charge on a photosensitive layer to apply a copying surface material.

909883/1487

(OBM) -5 U 20 Sl telegram ·: PATENTEUIE MOnihnt Bonkt Bayadtdi · Vereinsbank Mttndten «3100 PoshdMdii MOndien 653 43

BATH ORIGINAL

In electrophotography with the application of electrostatic charges, it is generally necessary that an electrostatic charge is transferred to the photosensitive layer of a copier surface, hereinafter always referred to as copier paper, immediately before it is exposed; that is, the photosensitive layer is electro- 3 ta table is charged. In the conventional '/ learn the type described above is a pair of wire - or Madelelektroden in an expedient spaced from one, between them copying paper, and _f between the pair of electrodes, a voltage in the range from T> -7 kV applied to generate the corona discharge. As a result, the sensitive layer is electrostatically charged by the ions generated by the corona discharge. In that case, the positive electrode generates the positive corona discharge, ie, the positive ions, while the negative electrode generates the negative corona discharge, ie, negative ions. Depending on the type and dPM properties of the sensitive layer of the copy paper, either the positive corona discharge or the negative corona discharge is used. For example, when the sensitive layer is mainly composed of ZnO, the negative corona discharge is used, while the positive corona discharge is used when the sensitive layer is made of Se. In the case of an electrically conductive one

80S883 / U87 .- /,

BATH ORIGINAL

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Co v> if - r paper ^ with a layer of ZnO on its one surface, the copy paper is first placed on an electrically conductive base or carrier, with the sensitive layer facing upwards, and a crazy wire electrode is in one A distance of about 10-20 * m \ vertically above the sensitive layer, so that an electrostatic charge can be transferred to the sensitive layer by the negative corona discharge generated by the wire electrode. On the other hand, the conductive base or such a carrier can be omitted. Then the wire electrode is placed vertically at a distance of 10-20 mm below the back surface, d, '].' that of the sensitive layer -les copy paper *: * is arranged against the surface lying against the surface, so that the positive corona discharge can be generated, whereby the electrostatic charge is transferred to the copy paper. In both of the methods described above, a high DC voltage is applied between a pair of electrodes. According to the invention, the waveforms of the voltages applied to the electrodes have been studied intensively and it has been found that the full DC voltage is not required for the transfer of the electrostatic charge to the sensitive layer * and that for this purpose also . a pulsating voltage can be used. The results of the invention have been confirmed by experiments.

909883 / UOf

BATH

If the sensitive layer is made of ZnO, the electrostatic charge is transferred to the layer by the negative corona discharge, as described above. In this case, even if a wire electrode is used, punctiform corona discharges are generated along generated by the wire electrode, so the sensitive layer Nir-ht is charged uniformly. To eliminate this The disadvantage is that the electrode has to be at a greater distance be placed by the sensitive layer or it a plurality of wire electrodes must be used, which leads to increased energy consumption. This appearance occurs with DC voltage and also with pulsating voltage with 5ü - 1GÜ Hz.

In short, the present invention provides an electrostatic charging method for electrophotography according to FIG which on a photosensitive layer of a copy paper an electrostatic charge by corona discharge is transmitted, which is generated by periodically or non-periodically recurring voltage pulses, each Voltage pulse a waveform with a steep rise and has a steep drop and a sharp point. . \.

The invention achieves the following advantages %

9098 83/1487

ORIGINAL BATHROOM

1323307

1 »els kaiki a smooth charge ensured t" tinxi ^; the consumption of utilities can be reduced

2. Inf.oige of the pointed Spannuixgawellenfvajrifl can be the beginning. the corona discharge accelerated werieaa ,, and the lü.ederho _; The cooling cycle can be shortened so that rapid charging is not possible. . .

3. The impulse spamnumg is active feocfe to the generation of the corona discharging »However, the energy is low, so that an electrical sciilag is only of .little effect. So if a spark discharge should start, the sensitive kick is less damaged»

4. As well as the liocre-frequency harmonics as well as the

f iederaolungsfre <iueaa: z der, voltage impulses are feock, se— that the coils and other components can be constructed in a compact manner,

'5. If a sinusoidal voltage, such as the commercial one available voltage is used for control the hawser of the charge, that is, of the Bötsntlals of the sensitive ones Layer that increases voltage or the electrode gap changed »In this case the voltage tends to rise to a spark discharge potential, which leads to Penetration leads to the sensitive layer,

909883/1487 ,. ., ·, ·. = \ ,.

ORIGINAL

can I like Erf Indan? the above regulation elsafaefe by adjusting the repetition frequency of the executed. With this simple regulation, the device can also be designed with a simple lonstrufetton m®A compact design. ; .- ■>

nd the invention is further explained in relation to the fee ige added Zei.chnun.geii »

Fig. 1 shows for explanation aaad for comparison with the

Charging method according to the invention who ^ chledeaae for Corona discharges

Fig. 2 shows schematically generated by wire electrodes:. · K-orona dischargeein, where the wire electrradein .- = -.- · - ,. Tensions with the WeIlsnforaaea shown Ln Fig. 3. be supplied »-. ■. , - · ... _: -.-.-- ■

From Fi- ", 1 the ^ earsciiledejae-n __" waveforms can be seen for Vergielehsziweelceiai, which are fair to the Erzeaagaaag. ■

Corona discharges are used »Daibel, the Spannaio are plotted over time. The time is plotted on the axis and the voltage on the ordinate. The voltage waveform used in accordance with the invention has pulses of steep rise and fall, as is the case with @ . The waveform ^ is that of a k-omm & rz t

■ * "T ~"

original

Current source or an oinus wave generator opannunR, while waveform 3 is generated by a ripple generator is generated.

In the Fi < ^r . 2A, B and C are shown the forms of appearance of jxQron'-ientladuiißren on wire electrodes ο for explanation. With a positive corona discharge, like Qie in ¥ ± y. 2A shown i _; t, the corona discharge surrounds the drah ⁺ ii shaped electrode completely, regardless of the waveform of the voltage applied thereto. In the case of a negative corona discharge, as described in iig. 2B, punctiform corona discharges are observed along the wire electrode ή, so that electrostatic charges are not evenly transferred to the photosensitive layer, as described above. iiur avoid such uiiglG iehmässigen-charging must be the Drnhtelektrode at a greater distance from the sensitive layer arranged, or there must be provided a plurality of wire electrodes, which leads to increase in the required energy. The above undesirable phenomenon is particularly observed when the voltage applied to the wire electrode has a frequency of 50-100 Hz. Even if the waveforms and Q are changed as shown in FIG.

909883 / U87

BAD ORIGINAL «.

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According to the invention, voltage pulses φ according to - t'i'go 1 are used and in the case of a negative r-orona discharge, then T-ur> kt-shaped horona discharges similar to those in i'ig. 2b,. The number of these discharges is however, verrli '^ h-en mi 1 of the number in i-ir .. 2Ü pe ζ e igen number increased considerably " corona discharge per 1-2 am is generated, v / earth according to ii /. 2C with the method per / asr-, invention ? - 4 iintladuiigen per 1-2 cm he; .- .ugt. i / ar ^; iberhjnaus can according to krfindungi -uie positive r.orona discharge around the electrode according to iig. 2A \ «. 'e; ieiitli (ih can be approximated, oelist in the case of negative corona discharge by increasing the repetition frequency of the voltage impulses, thus a uniform, - at! charge can be secured, and the electrode can be placed close to the sensitive layer, whereby the required energy is reduced.

fc i, ie the invention has hitherto been given special reference to their preferred embodiment described, of course Variations and changes are possible without leaving the general idea of the invention, as he did has been described above and is defined in the appended claims.

The invention thus creates an electrostatic charging

909883 / U87- ^ =

BAD ORiGiNAL

1323307

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BATH

Claims (1)

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