CS196505B1 - Appliance for the electric charging of the electrophotographic layers - Google Patents

Abstract

Device for charging electrophotographic surfaces with at least one corona discharge zone, where at least one corona discharge wire that can be connected with a high-voltage source is surrounded by a conductive screen, contains a screen that can be linked to the mass potential of the device or the back of the potential of the back of the layer by way of at least one discharge resistance. Value of discharge resistance is adjustable to parameters influencing the charging.

Description

The invention relates to a device for charging electrophotographic layers.

Equipment of this kind must meet a number of requirements. It must have high efficiency in terms of useful current and charging rate, must be accurately controllable and give reproducible results, must be structurally simple and protect electrophotographic material from damage and overload by high voltage jumps. Chargers of this kind are known under the names Scorotron and Corotron. They are designed to include at least one thin wire which is connected to a high voltage, beginning with a grounded metal screen and transmitting charge carriers to an electrophotographic layer moving near the wire. Although the Scorotron meets the requirement of accurate controllability and reproducibility and material protection, it is structurally complex and costly and has insufficient useful current yield, making it unsuitable for high charging speeds. Although Corotron is simple in design and protects the material, it also has insufficient useful current yield and does not allow accurate control and reproducibility of results.

SUMMARY OF THE INVENTION The object of the present invention is to overcome these drawbacks and to provide a charging device such that

it was structurally simple and safe against jumps, achieved a high yield of useful current and allowed high charging speed ·

196 SOS

Invention is a device for electrically charging the electrophotographic layers, with at least one corona track PES ^t ávaj ^s c ^s a NEJM ^E do not unity ^to oronov ^eh of wire ^kt era is connected to a high voltage source and is partially surrounded by a grounded - conductive diffuser open towards to the charged layer. The essence of the invention is that the screen is grounded via an optional resistor. The selectable resistor may consist of a single continuously adjustable leakage resistor. Alternatively, the selectable resistor may consist of a system of at least two leakage resistors switchable by a switch. The effective value of the leakage resistance - can in this case adjust a.vlastnostem type electrophotographic layer, the charge rate at a high voltage, shape and dimensions of the shield and its distance from charging of etetorofote ^ and ^ cm layer ^d AnyMem ateosifertekým podmtokám currencies and ^I C ^s is ⁱ n ^t enzit light conditions ^of electrophotographic layers. When it is at each of the electrophotographic obou.stran recharged vrstey- umtetěna orónov ^to one ^and you ojová path ^{b, the DE} and S ^ ^E No nttto grounded p es ^of a ^lit e ^l in the resistance.

The advantage of the device according to the invention lies in the fact that the efficiency of the charging device is substantially increased. The ratio of the useful-discharge current, directly used for charging, to the total discharge current is higher than in the prior art devices, without the need to increase the applied high-voltage and cause the disadvantages associated therewith. ZAMZE ^ -based VYN & Cutting subsidized fulfills all of ^{w s} s ^h ora Uve ^de n ^{e Z} and ^da Posts.

The invention is further explained hereinafter with reference to the accompanying drawings, in the N ^and C ^Hz O ^b r. 1 Zn ^and zor ^ò U is ^p RVN ^{even when} KLA ^dp rove ^d en ^d of ^y n and ^l cut with fine leakage resistance with ^{Ti Itk} and n, Fig. 2 illustrates the second · ^ò U is ice ^^ ^p rove en ^{d s} for zinetaaté paptoy invention, with - several leakage resistance, and FIG. 3 is a diagram of the efficiency of the charging device according to the invention pro- -svodového different values of resistance of the shield .

In the apparatus of FIG. 1 is a per se known manner disposed within the electrically conductive with ^{the tup} Units 1 corona ^d £ r ^ate, which is connected to the ^{y l} sokonapě AC source 1% · StUnítko

It is grounded via an adjustable leakage resistor 6. Under the charging device travel at U is ^b e ^l e ^kt ro ^f o ^t o ^g r ^f ic ^ka vrstea £, wipe-on nosiLčí. - to be charged by the Koranic discharge. The electrophotographic layer 6 is guided by means known per se.

In the apparatus of FIG. 2, one U-shaped screen 2 > 10 is disposed on each side of the zinc oxide layer 8 of the electrophotographic layer J. Within each of the two screens 2, 10, two mutually parallel ^{to the} blower are positioned to increase the discharge current. ^The wires 21, 12 and 13, 15 are shown. Qoranic wires 21> 12 are for ^p to ^{y kl} Ojen None hair dryers ^Ké voltage ur ^{ng kids Cite} toovně, zaWmco ^to OR ^and DR novel ^sulfates 23rd 14 are for ^p to ^y Ojen negative high voltage of a different level. Diffuser 2 J® Proper grounding switch to ground 15 and subtopics in a ^lb y ^- Bu represents ^{n BC} EC leakage resistor 16 or ^p res leakage from the 12th ^P or ^- Similarly, the grounding of the conductive shield 20 to ground through a discharge resistor 18 or through discharge resistor 12 as shown in the drawing.

196 505

Described device of Fig. 1 operates as follows: ^p of corona ignition tries carrier portion n ^ÁB drawbar ODT ^Affairs sttnHhm] ,. SVO ^d £ AC resistance complicates the drainage and thereby reduces the flight time of the charge carriers to the screen 1. The action of the charge carriers that strike the screen 1, the screen 1 becomes the potential that is between the ground potential, high overvoltages microns interposed corona wire on the second ^p o ^t ENC ^IAL stenítka 1 ^{l p} otenciálu ISI from the ^{bark of} the more gears, the greater the value of the leakage resistance £. The increase of the potential difference of m ^{and a} ce for us ^l e ^d e ^k zmeráení ce ^o o ^eh the above ^b ojov ^eh o ^p rou ^d u, but ^plated Rove ⁿ increases ^p Omer useful discharge current to the total discharge current, so that the useful discharge current rises until the saturated state is reached. A useful discharge current means that part of the total discharge current, which is an open side of the shield 1 is transported at electrophotographic layer 6. Course of this ratio is shown in Fig. 3 is fully withdrawn in ^{the bush} and It depicted ^ò U is the ratio ^of r ^eh uMtečnéto discharges of ^p Rou ^d u ^{to the} total discharge current, tepování in ^{the bush,} and u is at ^least It depicted ^zit e ^No discharge Prou Nu ^ ^{c and} the curve erchovan zor ^least Zn ^and u is the total discharge current depending on the value of the leakage resistance £. On the horizontal axis of the diagram in Fig. 3, the resistance is applied in mega ohms, on the vertical axis the current is applied in micro-amperes. Fully extended curve gives dimensionless values, not nice? Amperes.

As the leakage resistance £ increases, the potential of the screen 1 increases, and the risk of a flashover between the screen 1 and the electrophotographic layer 6 and between the screen 1 and the grounded components of the device increases. £ leakage resistance is therefore necessary to set the ^h o ^d u ^{t no, kt ER} opttmátaš sptóuje DEMAND ^{y k} e ^f with ^Ké ektivi ^those devices and ^p ožadavek electrophotographic material, in order of protection against damage. The choice of the optimum leakage resistance 6 depends on the nature of the electrophotographic layer 6, the charging rate, the high voltage supply, the shape and dimensions of the screen 1, its distance from the electrophotographic layer 6, the atmospheric conditions and the intensity of the electrophotographic layer 6. To a certain extent, the quantities influencing the charging of the electrophotographic layer 6 can be compensated by simply adjusting the leakage resistance. For example, by using different layers of electrophotographic charging shovel 6 maintain ^hl axis ^t, and ^the level ^of power in the ^{y KEH} NAP ^EIT equal or unequal if the ^TLI material wasps ^t £ adjusting the leakage resistance.

£ leakage resistance can be steplessly adjustable resistance control may be used or several optional zapínatelných-invariant resistors, as shown in FIG. 2. In the charging device for zinc papers shown in Fig. 2, is disposed on each side of the elec ^t ro ^f o ^t o ^g r ^f ic ^Ké vrstey J on carriers ^or eight ^to one oronov ^{and the} discharge ^{and expensive,} hazy in ^s and ^K operates essentially the same as the apparatus of FIG. 1, with the only difference that instead of a leakage resistance £ are modified two pairs of switchable leakage resistors

16, 17 and J ⁸ »12 · Level ^of High to the ^e-voltage korónovýoh on wires 11, 12 is ^plated from ^l ISN from levels ^{of five} to vysokáho ^to oronovýc ^h dr ^sulfate ec ^h 13 £ 1 and ^p rote is ^kd improve to achieve ^p timálního nabjecíto of course desirable that leakage resistors 28, 19 have a value other than 16. for the leakage resistances ·

19β SOS

Claims (3)

OBJECT OF THE INVENTION 1. A device for electrically charging the electrophotographic layers, with at least one corona pathway sestávaj ^I C ^s nejnténě from one ^to him oronov ^s draft, j ^{e kt} projecting into the cavity connected to a high voltage source and is partially surrounded by a grounded conductive diffuser open towards recharged layer characterized in that the screen (1, 9, 10) is grounded via an optional resistor. Device according to claim 1, characterized in that the selectable resistance is formed by a single continuously adjustable leakage resistance (4). Device according to claim 1, characterized in that the selectable resistor consists of a system of at least two leakage resistors (16, 17, 18, 19) switchable by a switch (15).