DE1047616B - Process for developing electrostatic images - Google Patents

Description

The invention relates to development methods for electrophotography and electroradiography as well as for Xerography and Xeroradiography. In particular, it relates to certain improvements that '' the picture easily and quickly with a greater degree of certainty and durability can be made and developed.

It is known for electrophotography to use a plate or paper that has a layer of a material with photoconductivity, such as amorphous selenium, this layer in the In the dark picks up and holds an electrostatic charge. This plate is then used for differentiation exposed charge in any way to a light pattern or other influence and subsequently "developed" by applying an electrically charged powder, so that if the powder has been applied to the plate, this in accordance with the charge on the different parts of the plate is absorbed by the plate, thereby creating a powder through this visible image is created.

With this type of development, it is difficult to distribute the powder in an even consistency, since if the powder is applied unevenly, the image is built up similarly unevenly, of course and does not represent the true reflection of the original exposure.

Furthermore, it is difficult to permanently fix the powder on the plate. For industrial use In electrophotography it is essential to achieve a permanent image. This permanence is currently usually achieved by the inclusion of a resin, which when it is in the form of dust has been applied to the plate can be fixed by subjecting it to heating will.

However, all these known methods have the disadvantage that it, regardless of the method the powder has been applied, it is extremely difficult to achieve an even coverage of the plate to ensure a build-up of the powder in the exact ratio is related to the image left by exposing the charged plate. To these difficulties too overcome is z. B. has been proposed to blow the powder onto the plate or by means of a corresponding to roll on a charged roller or small beads carrying the powder or to use a liquid, which is sprayed onto the plate, but the droplets dry as soon as they reach the plate, like this that they adhere to the plate only in those parts of the surface in which the powder thus formed is the correct one Has polarity with respect to the charge on the plate.

Method of development
electrostatic images

Applicant:

Commonwealth of Australia,
Melbourne, Victoria (Australia)

Representative: Dipl.-Ing. E, Rathmann, patent attorney,
Frankfurt / M., Neue Mainzer Str. 40-42

Claimed priority:
Australia, December 29, 1955

Kenneth Archibald Metcalfe, Graymore,

and Robert John Wright, South Payneham (Australia), have been named as inventors

The object of the invention is to improve the image, i. H. to develop in a better way. This is achieved by a process called "wet development" here. The invention aimed at producing an electrostatic image on a corresponding surface, which then developed on this or transferred to another surface and by wetting the same with a Carrier liquid is developed whose electrical resistance is so great that a destruction of the electrostatic Image is prevented, and in which a pigment or dye carrier is dispersed. Of the Dye carrier has a charge of the correct polarity. The carrier liquid can also be a controlling one Substance to change the charge can be added in connection with the electrostatic Image on the surface causes the image to develop. In addition, an agent can be present in the developer liquid be dispersed, which fixes the pigment on its carrier indelibly when the liquid evaporated or removed. The fixing agent can also be used at the same time with the appropriate selection be the controlling substance.

It is clear that where the pigment is in a neutral position, the charge on the plate is non-destructive Liquid with great electrical resistance is embedded, at least during the entire picture

809 700/486

3 4

the duration of the development evenly of the single-acting desiccant

is subjected to a liquid in which the cobalt naphthenate 0 5 ° -

Dye uniform and in general proportion- Manganese naphthenate ''. '.'. '.'. '.'. '.'. '.'. '.'. '. θ! δ J

is dispersed over a distance. This causes a _ toluene 100 ° ·

rapid deposition of the dye in a density, 5 ""' ^ö

that of the strength of the various parts of the

Picture exactly corresponds to the charge held. These substances are ground together for 8 hours in a spherical vaporization of the liquid from the developed image, until it becomes a mixture with, if it is relatively highly volatile, that of a smooth consistency. After mixing, quickly leave the image in a dry state, so about 100 g of toluene can be used for the purpose of atomization, if a fixing agent is added or for exercise or for application by means of rollers, for which, if the developer has this property, the coloring Print, for spatula or for the overlay that adheres firmly to the surface that has now been developed. draw can be added by immersion.
The high-resistance insulating liquid also makes it possible. This paper is now lent to a spray discharge that the particles carried by it are subjected to the required.

have the same electrical parameters and load it. The parameters can, however, be placed by a metallic plate electrode and immediately below Changing the composition of the liquid also placed a metal tip attached to the negative terminal can be varied. The change can be, for example, a direct current source with a voltage of 10 by adding one connected to either the liquid or 20 to 20 kV. The flat metal plate The controlling agent acting on the suspended substance is connected to the positive electrode. That The substance. With this paper means the spray discharge is then 10 seconds can be exposed to an extremely sharp and fine-grained long, with the tip 5 cm above the Achieve a picture because, unlike the dry process, paper is held. This can be through a wire Ren, which is due to the limitation by the particle 25 or a group of wires or a sharp size and due to the agglomeration ratio- knife edge about steel can be replaced. In Provides moderately coarse-grained images, a liquid ent- in this case can be the distance between the wire winder for the deposition of the pigments in colloidal or knife and the paper and shredded the chipoder approximately colloidal form or for a diminution in order to achieve a uniform electrolytic possible extend to colloidal form - to achieve 30 Irish field strength, measured in volts / cm, the deposit was found. It has been shown, In another arrangement, a charge can do this of the images developed in this way are applied by that the paper between Extraordinarily strong enlargements without damaging capacitor plates or the like. Placed and then thereby borrowed grain effect can be produced. irradiated or exposed that it is then in a

Without going into these advantages in detail, the camera or the like is exposed to light

be aware of the various difficulties, or that an image is imposed on him or in one

indicated that previously occurred when the application is imposed in a different way, which is based on the elec-

a dry, extremely fine powder can be generated in a trisch charged surface of the paper

Air was necessary, as this is an additional carrier and subsequently developed

means necessary, whereas such particles 40 It has been found that the electrostatic

easily held in a suitable liquid, and charge can in some cases also be generated

from this in the required uniform after the paper is made of the image-forming means

division can be deposited. has been set.

To explain the main features of the process The development then follows by simple construction

According to the invention, examples are given below for applying a liquid to the paper. This can

wrote. ·· ■ by immersing the paper in the liquid or

In these examples, certain substances are applied by pouring them on, spraying them on or spreading them out

which are in the trade under a special name. a roller, another application device or

There are: an electrode to be made. The developers-

»Rhodene L 6/100«, a linseed oil-modified alkyd liquid consists of an insulating liquid

medium oil length resin; Fabric that carries the colored particles. This liquid

"Pentarol 20", a phenol-modified pentacy, can be, for example, a cyclohexane, the

Erythritol resin ester; - a very high resistance and a low dielectric

"Fusis A", a highly aromatic solvent, has a tricity constant. In this liquid becomes

high boiling point, and 55 carbon black or other dye and a controlling agent

"Monolite Yellow" and "Monolite Red", two solid substances dispersed that give the dye the necessary

organic dyes in yellow or red color. given electric charge or modifying this charge

For example, a piece of paper or another is fied. For example, if the dye has a positive

suitable surface with a mixture of zinc oxide, tive charge should have, the liquid is called

an alkyd resin and a drying agent (siccative) 60 controlling substance and an alkyd resin as a fixing agent

coated, which is suspen- added in a diluent, while then when a negative charge

are dated, and after the mixture has been applied, linseed oil is required as a control and fixing agent

dried. is used.

A typical coating mixture contains e.g. B .: The following is an example of a positively

Zinc oxide (produced in an indirect 65 loaded developer paste:
drive, mostly non-fluorescent, with a refractive index of 2, »Pentarol 20« 15 g

such as the painter's dye, known as "RhodeneL6 / 100" 15 g

Durham special zinc oxide is known) 150 g "Fusis A", 25 g

Alkyd resin, such as "" RhodeneL9 / 50 "100 g 70 phthalocyanine blue, 150 g

The "Pentarol 20" is unlocked in "Fusis A" - emphasized that the development time with the

sen, heated to 232 ° C until it is dissolved. above concentrations when developing in

After dissolving, "RhodeneL6 / 100" will pull shells for about 15 seconds. But if the

give. The phthalocyanine blue is then very low with the concentrations, can be longer Resins in either a ball mill or about 30 seconds development may be required

The triple roller mill is completely mixed until the required full color saturation is achieved.

Bring the color particle size to the required fineness.

is brought, d. H. on average to about 0.5 microns. For if a conductive during development

For most purposes, an 8-hour grinding surface, such as a metal plate, is sufficient; an applicator roller in a ball mill. Is used as an example of a negative od. The movement of the

Loaded developer paste is indicated: _ Dye particles accelerated to the image. Such

Boiled linseed oil 25 ° - surface can even be used to absorb and continue

Lead chromate ■ '75 «■ these dye particles serve, which. from the electro

Desiccant (lead naphthenate) "! 0.5 g static image are thrown back. This causes

15 em a cleaner picture.

The components are ground together for 8 hours in a The drawing represents, in simplified form, the development ball mill. Operation represented by a liquid medium. The bottom In both cases, the paste is used as the basis for the bowl is 1, the surface charge carrying a dispersion in a liquid with a high paper with 2, the liquid with 3 and a roller volume resistance. Denoted by 4 as an example of the 20.

Dispersion method serve the following instruction: When the paper 2 is immersed in the liquid 3

A small portion of the paste will be required in which will occur a flow of the dye particles, which as

Liquid, the n-pentane or carbon tetrachloride dots are shown, roughly in the direction of the

can be stirred in and to remove the arrows. The particles move naturally

Completely disperse parts of the strained paste. 25 Hch free under the action of those known genes

Before use, the mixture is to achieve a set that is suspended in insulating liquids

fine grain developer filtered through paper. Master the particle. However, you will because of her

The filtrate is used as a developer. The concentration polarity preferably to the charged areas 5

tration of the dispersion can be varied at will. The paper 2 moves to which it is held.

will. A typical concentration of one should. This movement exposes the fluid

Added dispersion consists of a suspension of at the points 6, whereby the surface at these points

0.5 g developer paste in 100 ml liquid. stays clean. The effect of the roller supports

One of the advantages of a developer of this type is rapid development in that it is used as a

it says that, because the dye particles in an electrode to enhance particle movement and

Contain liquid with high resistance and 35 also for the displacement of the particles into the neighbors -

Therefore, all particles are isolated, the special property of the charged surface of the paper 2 acts,

male of the controlling substance, such as the alkyd - whereby it picks up particles at the points 7, where-

resin or linseed oil, which also removes the fixing agent from the areas 6 by the particles

can be medium. This ensures that there will be a filing.

40 The use of wet developers of this type moderately and directly proportional to the positive or causes the production of an image with extremely negative, as a result of the application of the image on a fine grain size. The picture thus shows a higher charge on the paper. Degree of sharpness than with other means, i.e. a mixture of, for example, cyclohexane and either by electrophotography with dry twick carbon black paste in the ratio of 0.5 g paste to 45 lung or by halogen silver photography with equal to -100 ml of cyclohexane or generally in the range of value sensitivity is achievable .. For the S elen-0.05 to 5 g carbon black paste to 100 ml cyclohexane delivers plate easily a dissolving power of not a very fast drying mass, which, if it reaches less than 1000 lines per millimeter, It is clear that it is also possible to achieve two wear resistance, since the cyclohexane evaporates 50 dene dyes or two different colored dyes and the carbon black is as firmly adhering as ink or the like to disperse the liquid leaving it behind. The invention therefore provides a method of selecting that both have opposite electrical properties, which have a very rapid development of electrical properties. They are therefore made possible on a static image that has a high degree of resistance to different parts of the irradiated or exposed and does not deposit any further treatment area, and so at the same time requires the positive and development to improve this property. Negative sections of the area in various It has been found that the use of wet paints will develop. In the following, an example is given to developers of this type and the above-mentioned combination of a developer which contains two dyes decentration, a complete development in 15 opposite polarity, which can be selected when the dispersion has been achieved by one 60 that the Negatively and positively charged dipping the paper or the plate into a shell made of metal, glass or enamelled so that picture elements are simultaneously unfilled in different colors: metal is applied. p _{aste A> neo} . _ativ o- _e load

If the developer is applied while, ', ^Ö _T. ^. «-

the plate or the paper between conductive or 65 geKocntes .Lemoi ^ a ₀

relatively good conductive rollers passes through it, ^ aamiumseienia, «« .... / O ^

,. ,, ... j · ·. TM ·· · 1 "-x. U χ. Χ, -j · i j · dryer (blemaphthenate) 0.5 g

which are completely wetted with liquid, the \ r> &

Development time reduced to less than 1 second - Paste B, positively charged

set. However, it gets better in meters per second "Monolite Yellow" G, N. S 75 g

and is then about 60 m / sec. Let it be 70 cyclohexane 100 g

Claims (1)

7 8 0.5 g of each of this paste is brushed onto the surface for 100 ml X-ray purposes. ZyMohexane given and fully dispersed. let the following composition be given: _ It is also possible to use this method for over- »Rhodene-L9 / 50« resin 100 g Emanderlagerung of pictures of different Jt ¹ arben Zinkox vd! 130 s? to use. In this context, let there be 5 black lead '* 20 « pointed out that repeated irradiation of a Cobataapbthenat ". '.'. '.'. '.'. ','. '.'. '. 0.5 g Paper and by developing each time with a manganese naphthenate Q-, 5 g * other Jbarbe em multicolored picture can be built up toluene 100 s which can ultimately lead to a " new kind of color photography can be achieved. io These substances are placed in a ball ais for 8 hours Example of a way to make colored mill ground together. Developer is applied to the composition specified above. The mixture can be applied to a surface made of paper, media Set for a positively charged, Pbthalocyaninblau tall or other substance brushed, sprayed or Referring to containing dispersion. by immersion, electrophoresis or after a The phthalocyanine blue will be applied by a number 15 other methods different colored dyes, such as by »Monolite Another substance for painting on surfaces Red "and" Monolite Yellow "or by certain are composed as follows: knew inorganic dyes, such as cadmium "Rhod: ene-L 9 / 5O" resin 50 g red or chrome yellow, replaced. Care should be taken to keep sheet metal 200 ^ that these colored developers mixed properly 20 cobaltoaphthenate 0 25 g xverden to make mixed colors such as Maagantiaplrtheiat ''.'.'.'.'.'.'.'.['. 0 ^ 25 g Purple, prange. Brown or the like. Carbon black diluents can also be used: toluene, to achieve shadow, white dyes, such as _w j _e erforderiicb
such as zinc oxide or the like, to achieve halftones. or black and white dyes to achieve 25 It should be emphasized that a principle for the shadow effect is added. The possible selection of metal oxides or other substances for the production of multicolor images by X-ray purposes depends on the use of a substance that contains an element that naturally has an absorption as well as in multicolor printing from the line in the frequency pool , which is particularly desirable for spoiling the transparency of the dyes used and for use for X-ray purposes. In the composition given above of the electrical resistance of the dry pigment, for example, after deposition on the paper or plate, contains. wise the lead oxide, which forms the active substance, lead, but greater difficulties arise when it has an absorption line that absorbs an X-ray beam superimposition of the usual dyes to produce from a voltage of 70 kV,
does not set up a multicolored image. In addition, it is of course possible to use paper or the like around which it is possible to wrap the color density of each individual object and develop it. Partial image can also be controlled individually by exposure or development, with normal radiological sub-images or together, ie color correction searches, for example for clinical purposes, one is still easily possible. more effective method insofar as that It is also possible in a new way to develop a 4.0 paper simply treated in the manner described in three or more colors. and then immediately to produce the X-ray. The development in a color, e.g. B. in red, the image can be developed. The final termination before sufficient electrical charges are formed is permanent so that it can be stored on the paper or plate without fear of deterioration.
after which the paper or plate is moved to another 45
Developer, for example blue, is immersed and part of the image turns blue. This treatment becomes ρ _K ,., .. _{N,. v χ s} ,, _{R (} . _{cu E.}
then continued with yellow, for example. The result is a color image which, however, does not necessarily have to show the correct colors of the object. characterized in that the electrostatic It is clear that the invention can also be applied to the already image-bearing surface with a liquid developer known selenium plate can be applied, on is exposed, whose liquid phase has a so who develops the image easily with the liquid or has high electrical resistance so that a disintegration Mi * another pretreated area advertising transferred ₅₅ case des'elektrostatischen image is prevented, which can then be developed in this way. _un dj _n the one elec- If the invention disperses pigment with an antic selective effect on the electroradiogran and is turned, the X-rays become an electrically selective one of the pigment subjecting surface containing a heavy metal oxide, controlling substance, such as lead oxide, which is capable of 60 2. Method according to claim 1, characterized in that to absorb larger amounts of radiation. The area shows that a developer is used that or the paper is then, in the same way, containing an agent which indelibly acts so that on it an image of an electrostatic bar is fixed on the surface when the liquid Pattern remains, which is then evaporated in the same way out-phase. can be wrapped. As a result, the object, 65 3. The method according to claim 1, characterized in which is to be x-rayed, are treated by oneself, so draws that a fixative is used which that the X-ray image, after completion of the penetration, simultaneously acts as a controlling substance for the charge treatment and after treatment of the object with that of the pigment is effective. Developer liquid on the outside of the counter- 4. The method according to claims 1 to 3, there- state appears. As an example of the substance, which is characterized by the fact that a developer is used, in which a substance acting as a dryer is present. 5. The method according to claims 1 to 4, characterized in that the controlling and at the same time fixing agent an alkyd resin is used. 6. The method according to claims 1 to 4, characterized in that an oil as the control substance is used. 7. The method according to claims 1 to 6, characterized in that a developer liquid is used, in which at least two coloring substances are dispersed, which act on the different Parts of the image charge are electrically selective. 8. A method for developing electrostatic images in multiple colors according to claims 1 to 7, characterized in that the development is initially carried out with a liquid in which a uniform dye is dispersed, followed by another electrostatic on the surface Image is created which is then developed with a liquid containing a dye a different shade than the first is dispersed. 9. The method according to claim 8, characterized in that that the process steps of image formation and development with black, white and different colored pigments are arbitrary be repeated many times. 10. The method according to claims 1 to 9, characterized by the use of glaze dyes. 11. The method according to claims 1 to 10, characterized in that the development is carried out by immersing the surface carrying the electrostatic charge in the liquid. 12. The method according to claims 1 to 10, characterized in that the developing thereby causes the developer liquid over the surface carrying the electric charge is moved away. 13. The method according to claims 1 to 10, characterized in that the application of the Liquid on the surface carrying the electrostatic charge by means of a special device he follows. 14. The method according to claims 1 to 13, characterized in that for development uses a conductive surface located near the surface carrying the electrostatic image will. 15. The method according to claim 14, characterized in that a conductive, with developer covered surface is passed over the area to be developed. 16. The method according to claim 15, characterized in that the developer applying Apparatus part is designed so that it repels the electrostatic image color particles attracts and continues. 17. The method according to claims 1 to 16, characterized in that for generating the electrostatic image a selenium plate is used. 18. The method according to claim 17, characterized in that the electrostatic image before Development from a selenium plate is transferred to another surface, which is responsible for the charge distribution holds, and is developed on this. 19. The method according to claims 1 to 18, for application to electroradiography, thereby characterized in that the electrostatic image is generated on a surface which is a heavy metal oxide contains. 20. Liquid developer for carrying out the method according to claims 1 to 19, characterized through a liquid phase with one to prevent the decomposition of the electrostatic Image charge sufficiently high electrostatic resistance and a dye dispersed therein, which acts electrically selectively on the image charge, and one the dye over the Electrically selective control substance for image charge. 21. Developer according to claim 20, characterized by a fixative for fixing the Dye on the surface after evaporation of the liquid phase. 22. Developer according to claim 21, characterized in that it contains a control substance, which is also the fixative for the dye. 23. Developer for performing the method according to claim 1, characterized in that that the liquid phase is a volatile substance with a low dielectric constant, in particular cyclohexane or toluene, that contains a dye, in particular carbon black or zinc oxide, is dispersed, and that they are a fixing and a control agent for achieving an electrical Selectivity of the dye with respect to the image charge and for the fixation of the dye Contains evaporation of the carrier liquid, for example from an alkyd resin or an oil and that a drying agent, in particular cobalt or manganese naphthenate, is also added is. References considered: U.S. Patent No. 2,726,166. 1 sheet of drawings