DE1597900A1 - Electrostatic latent image developing device - Google Patents

Description

Patent attorneys Dipl-Ing. F. Weickmann, Dr. Ing.A.Weickmann

Dipl.-Ing. H. "WEfCKUANN, Dipl-Phys. Dr. K. Fincke Dipl.-Ing. F. A. Weιckmann, Dipl.-Chem, B. Huber

Q-Q S MUNICH 27, DEN

MOHLSTRASSE 22, CALL NUMBER 413921/22

RANK XEROX LIMITED
Rank Xerox House
338, Euston Road
London, NW Λ
England

The invention relates to a developing device for latent electrostatic images for the generation of electrostatic reproductions with no background drawings.

In the conventional xerographic technique, continuously tinted surface portions of an image can be made with a xerographic selenium plate can only be reproduced after very careful preparation and when using additional facilities. Has the Surface load over a large area a uniform density, thus there are electric pads only in the air space near the edges of the charge pattern present where the change in surface charge density or there is a potential difference. In the middle parts, the field is entirely within the dielectric or dtr. photoconductive layer and therefore creates the middle 'Part of such a surface charge pattern no attraction for oppositely charged developer particles, among the

τΐ-ΟΟ 9 8 3 5JJ JS 20

Under these circumstances, electrical unfortunately appear close to the air - ■ the image area only where there are irregularities or changes the surface charge density are present. For the development of continuously tinted parts of the surface, various additional items are used. devices such as fluorescent screens, multiple development electrodes and related Circuits used «all main frames for improvement However, the development of continuously tinted areas generally affects the development of the line drawings.

A device for developing latent electrostatic images on a moving photoconductive plate with finely divided electrostatic toner particles is characterized according to the invention by an endless dielectric belt in the form of a (jitter, which is moved close to the latent electrostatic image, through a device for applying the finely distributed! toner particles on the belt and to create a bond between these! particles on the belt _K du | "ch an electrode arranged close to the photoconductive sheet behind the belt and biased in the same direction as the charge polarity of the toner particles to repel the toner particles from the belt onto the latent image , and by means of a device for moving the electrode in such a way that its distance from the tape determines the amount of toner particles transferred from the tape onto the tentative image.

The present invention refers to φί a device of in the üS-Eateitschrift 3 257 223 described in the likewise an endless arrangement provided with toner for over * transfer of the toner to a latent electro-static image

turns wigrd. However, the device according to the invention is much

easier, it needs a simple mesh belt instead of one .! more complex manufactured flexible, leW. efficient tape and the generation of powder clouds. For optimal development for A movable electrode is used for line drawings or tinted parts of the surface.

In the following exemplary embodiments of the invention are based on the Figures described. It aeigeni -

Fig. 1 shows the schematic sectional view of a according to the invention trained xerographic reproduction machine, '.

and

-Fig. 2 is a schematic representation of one according to another

• xerographic viewing

Embodiment of the invention trained / reproducing machine.

For a general understanding of a typical xerographic process sequence, in which the invention can be applied, is the device shown in Fig. 1, in which the various Components of a typical xerographic machine are shown in detail are shown. The surface of a xerographic drum 12 rotates on the axis I3E-1 in the direction indicated by the arrow direction shown, is with the corona discharge device Ί4 charged and via the lens 10 to generate a the latent electrostatic image with the light image of a document D exposed. Then the exposed IrommeToberflache arrives by a defecation point A, which will be explained in the following

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Licher is described, an image transfer point B and a component part C. At the image transfer point B, an image carrier tape P is guided from a supply roll 22 via cones 18 to the drum and, after detachment, onto the receiving roll 20. The length of the image carrier tape between the rollers 18 is in intimate contact with the developed surface of the drum 12, and by applying a charge by means of the corona discharge device 23, the developer material a is transferred to the tape P. The developer material is melted on the belt P with the heat-fixing device 25 arranged in relation to the second sleeve 18 and the take-up roller 20. All of the unification point 0 is another corona discharge series 26 forget "which applies a charge with a polarity opposite to that of the device 14", furthermore, a two rotating "brushes k" ( and a iiüfcip.e 2ö aur ^ htl & duhg (Lq ^ 'i'romiiieJLoüerflaöhe \' l before «jjecehen«

In the development parts α there is a jiihtwiajElunjöexnriohtung, the housing of which; O in its lower part ^{contains a supply of 2oner r} J * Furthermore there is an endioao :; dielectric grid »band 31 is provided * which is guided on the lobes 32 and 33 and runs past the circumference of the drum 12 * Die ^ ot; Band is also led around the iiolle 34 _? those in thy untore part of öehüuyos 30 ir. Sntv / icklerstci'fvi. rrat arranged i: .t »- A dor Hollen Vd or;> can be nit a ^ x -triebocystem to the kcnt ^ KUVend movement of the .Band 31 vei / o-üaien» Ur ;, oine;: cv; eerun ^ des Benöeü 31 in contact with the unxsrcn -Jc! .1 of the u? Rci .., u "l uui. gioicJi zoi t: 'g a lie der Helle 34 lnnorriclc des Hntv; lc ": lunj ^ jd-. v.uccc. ku ev: noß-

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The roller 34 is preferably equipped with a pressure roller 35 combined, which acts on the outer surfaces of the belt 31 and the axis of which is not aligned with the axes of the lumps 32 and 33 is.

iiiischen AEEN by the toner running parts of the band; · 1 i.jt. a triboelectric generator 3b is arranged, which applies a triboelectric charge to the toner particles within the toner supply.

The belt moves in the line shown by the arrow and is guided into the toner after a development process. While the band moves through the toner, the band and the toner particles are charged by the frictional electrical generator, which consists of a suitable frictional electrical generator. x> el represents reversal of Baiiaec is made to two flange surfaces and in the holes or CJfhungc-n of gitterformit _, 's band toner on. As it emerges from the toner, the band av / iuc-hen sv? Ei ooliabern 37 is carried out, which smooths the toner on the jana and transfers excess toner into the lattice-shaped Gev / eoe other UE;.. e_v ΔΪΛ-j sigen Tonerteilohen -verden of band scraped and f .- ΙΙόΐι iu the Tonervo'rarat of iiintv'ieklungogeLüuses> 0 aurüol :.

The band, which is uniformly provided with toner, is now passed under the xerographic drum 12 either in direct motion with it or at a small distance below the tangent point. ; n.ra the "latente- jild an die iinx v / i cklungö et eile A. uer-

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BATH ORIGINAL

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stated, it is developed by the toner particles present on and in the belt. The tape returns to its original housing and takes older tones in the manner already described . Advantageously, the movement of the base 31 is synchronized with the circumferential speed of the drum when the ana vjxv. Confesses to a gray material and with the 'i'rcinmel in ^ eraiirung comes to avoid a blurring or a destruction of latent or developed Jildes on a drum. i.je 'from strips of Zcrni ::> egg fur, ^ v ε: ο! 1 it preferably a / en minor.'. üst ^ nd vun ler CroiaiElflLiaho habjx,., or. .zx ■ • ji'iaü ^ lijheri , dL. _; , just let Haarüpifcz ü. " -... n '"or Tr ..;" iisioberfläcl.a vritlanj 3treiolion, v / o ^ u. the Ü-you: viL.di _o i; eit de .; iianaes greater than those of the

The rilddialrue and the ^r Jönung dar äurchgäi ena to be sounded Plächent "-ile v / erdsii by a moving development electrode ZQ "; j ^! ; imm-j, which is located under the _ur.dteii passing directly on the tangent enp arict. ^ pannun _o r.iit der dor polarity of vsnerlüdun ^ ^ ieicjhen polaritytrsüugt. i'er-iier lot rait der 31e-.:troae; 'o ^ ino retainer 4-0 aiechuiiijüh vsr-buiiuon, the üd 1,1 ^: " l ~ z :: - z oe -iLlher an 'Ii.o ^ UiI 1 oaer -..- 3:. "" jer of ΙΙ ^ οβΐ :. \ veg be'.vegt. Dieje .-, i.ricntung icanii through an ilncpf & uf lern ^ idisnungsfe ^ d ler -loprDcLul: ticnsma -.-: hiiie εχη _ο ΐ ^ τ ^ 11τ · "earth. _f ; iri di & ^ le.itrodo relatively close to ...: _. land hc: - ..: - jeuT (i.:hx, co ir .; -.- in--,. ^ urjligelivi .-. e fxäjheatou

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the layout of the line drawings is improved. Zv.'i ..; cheii The i £ Le, -: troae with e: tr actuating device can handle these two extreme positions 40 to control the teniuijüücftto de :: developed latent image. Audi can have an attitude on the different tint values o for identification or line drawings vorgL ^ .muen .- / earth.

In Fig. 2, an embodiment of the invention lndun ^ i-.eai .-. Äe.n 3inriehtung is shown, in which the development is carried out at a different point on the surface 12. The pictures ^ eudie picture transmission and the drum cleaning b ^ / r "Trcmmel" ϊβ & άβη As with · the arrangement shown in Hg * 1 through- nnä are deöiieXb Mt dejtis ^ lben Bezyg-s ^ eieheii ver An aev liötwiökitingsötelle "A in fig. 2 there is a 3i USe 41 to the side of the axis of the holy man. "13as EhtWicI 41 eöthäl-t vain supply of ion particles d? # Ptrner lot rushes the electric sitterbahd 4-2 provided , which the drum" tiüif afig at a point lying on a different upper circumferential semicircle

; * ■ Saa. Volume 42 runs between a-ivei rolls 4i and 44 ,. v / ouei butere Holle 43 iait a drive-in- ⁱ i: jh ', ung ßur kontlftuier «

!. Movement iet verbunien the tape * The lower "Olle -44 is located within the developer material is depleted in Sehäuse 4 '*' Mn deffl already described similar triboelectric generator 45 is swischen the two band parts inn ^ ia.11 · iss toner ^angeo2; dnet * As the point of contact of the sand 42 on the drum 12, behind the belt at a short distance there is a development electrode 46 which, in connection with the electrode "JS in? G. 1 described way works. '"■,' 009835/1520

BAD OfiiGlNAL

How the Pig. 2 corresponds to the device shown exactly that of Fig. 1, 'wherein the tape through the Toner supply is moved in the direction shown by the arrow through and takes up toner, which is electrostatically on Tape sticks. There are also the scrapers 47 are provided, which press the 'toner particles into the openings of the lattice-shaped belt, whereupon the tape is brought up to the periphery of drum 12 for latent image development.

From the foregoing it can be seen that the in Pig. 1 and 2 enable the development of continuously tinted surface parts and line drawings, indeir only the development electrode is adjusted relative to the moving dielectric development belt. A with the invention Installation in electrostatic copying machines The development process carried out enables the construction to be more compact Arrangements and does not require seals, which are generally used to prevent the leakage of toner from the developer housing. The developing device according to the invention can be at any point on the surface of an electrostatic Trdiaciel within a conventional electrostatic Copier are located.

The invention has been described on the basis of two execution sb ei spjele, however, it is not limited to these. Other embodiments will be apparent to those skilled in the art after knowing the above description and combinations possible, which err ^ esant through the basic idea of the invention includes grounding.

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Claims (9)

P a t a η t a η s ρ r ü c h e 1. Device for developing latent electrostatic images on a moving photoconductive plate with finely divided electrostatic! toner particles, g e k e η η ζ e i without t by an endless dielectric belt (31) in JPorra of a sitter, that close to the latent electrostatic Image is moved past by a device (3.6) for application the finely divided toner particles (T) on the belt (31) and to create a bond between these! particles (Q?) and the Belt (31), through a near the photoconductive plate (12) arranged behind the belt (31), the charge polarity of the Toner particles (T) pre-tensioned bleed ends (38) in the same direction for Repulsion of the toner particles (T) from the belt (31) onto the latent image, and by a device (40) for moving the Electrode (38) such that its distance from belt (31) determines the amount of toner particles transferred from belt (31) to the latent image (T) determined. ' 2. Device according to claim 1, characterized geke η η ζ eic Toi.ii et that the grid-shaped belt (31) on eiiier number of rollers (32, 33) 34, 35) is guided in such a way that it is within a first area the latent electrostatic: »image past and within a second area ^; is passed through a supply of toner particles (T). 9 ORIGINAL 009835/1520 3. Device according to claim 1 or 2, characterized in that g e k e η η that the device for applying the toner particles (ϊ) to the belt (31) is a triboelectric Generator (36) for the electrostatic binding of the toner particles (CT) to the belt (31) and a distribution device (37) for pressing in " of toner particles in the grid openings of the belt (31). 4. Device according to one of claims 1 to 3 »thereby ge indicates that the device (40) for moving the electrode (38) for developing latent images with relatively large, continuously tinted areas of the surface of the electrode (38) closer to the belt (31) and moved further away from the belt (31) for the development of line drawings « 5. Device according to one of claims 1 to 4 »thereby ge indicates that the photoconductive plate is the Porm a drum (12) and that the belt to the development point (A) the drum circumference is brought into continuous contact, the electrode (38) on the the drum (12) facing away from the Banles (31) near the Contact point is arranged. ^: . ■. ■ ■ l j- -ΙΟ " SAD 009835/1520