DE2165901C3 - Process for the re-enlargement of microfilm originals - Google Patents

Description

and or

CH,

wherein

Xi and X2 are identical or different and are hydrogen, Alkyl or alkoxyl with 1 to 4 carbon atoms each, halogen.

X3 and X4 are identical or different and are alkyl, Alkoxyl each having 1 to 4 carbon atoms, halogen and

η is an integer between 6 and 10

mean,

consists,

the development of the latent electrostatic image with a suspension developer, the one Toner with a vinyl-toluene-acrylate copolymer, a styrene-acrylate copolymer or a butadiene-styrene copolymer as High molecular weight resin in a short chain hydrocarbon carrier fluid with a Kauri · butanol number below 30 and

the transfer of the toner image to an image receiving material.

2. The method according to claim 1, characterized in that a photoconductor is used which contains a polynuclear, carbocyclic aromatic substituted by chlorine or bromine.

3. The method according to claim i, characterized in that that a photoconductor is used, the polynuclear carbocyclic aromatic 3-bromopyrene contains.

4. The method according to claim 1, characterized in that there is a suspension developer is used to which a minor amount of a tackifying resin is added.

5. The method according to claim 4, characterized in that the suspension developer as a tackifier Resin α- or /? -Pinene, polyolefins, heat-reactive synthetic hydrocarbon polymers or pentaerythritol ester of hydrogenated rosin is added.

6. The method according to any one of claims 1,4 or 5, characterized in that there is a suspension developer is used to which a plasticizer for the high molecular weight resin is added is.

7. The method according to any one of claims 1 or 4 to 6, characterized in that one Suspension developer used, which is a pigment compatible with the high molecular weight resin of contains a mean particle size of 25 ιτιμ.

8. The method according to claim 7, characterized in that carbon black is used as pigment.

2j 9. The method according to any one of claims 1 or 4

to 8, characterized in that a suspension developer is used which is a suspension vca 03 to 1.4 percent by weight of finely divided Pigment with electrophoretic properties and

jo 1.5 to 4.5 percent by weight of a high molecular weight Resin in the carrier liquid in which the resin is essentially insoluble.

10. The method according to claim 1, characterized in that when using one and the same

π suspension developer, the sign of the charge on the photoconductor is simply reversed, if, instead of a negative microfilm original, a positive microfilm original is re-enlarged.

11. The method according to claim 1, characterized in that that the development of the charge image in the presence of an external, essentially perpendicular to the photoconductor layer extending additional electric field takes place.

12. The method according to claim 1, characterized in that it transfers the developed latent image from the photoconductor to a preheated to 30-100 ⁰ C paper as the image-receiving material.

13. The method according to any one of claims 1 to 12, characterized in that there is a photoconductor used, which contains 0.1 to 0.4 moles of activator per mole of basic monomer unit.

14. The method according to any one of claims 1 to 13, characterized in that a photoconductor layer is used, which is based on 1 g of polyester as a binder, 2 g of 3-bromopyrene resin as a photoconductor and 0.22 g of dicyanomethylene-2,7-dinitrofluorene as an activator.

The present invention relates to a method for back enlargement of microfilm templates.

Such methods are known and have been used successfully. There is, however, a strong one What is needed for a microfilm re-enlargement process that can be used to make positive copies of can use both negative and positive templates.

It is also known that with different chargeable toners from one and the same original negative or positive image can be formed electrophotographically, but such could Process not enforce because it is technically and economically extremely complex to use a device to build that can work with two different toner containing developers.

In DE-AS 15 22 610 an electrophotographic process is described in which /.ur Errröglichung eic-ϊΓ positive copy starting from a Positive or from a negative as a template, a photoconductor layer coated with a liquid and the photoconductor layer coated in this way is charged and then developed as a liquid. This method is extremely complex and prone to failure.

Devices are also available that work with zinc oxide as a photoconductor layer on paper and that are positive and enable negative charging. However, these devices have all the known disadvantages of the zinc oxide process. It is particularly annoying that normal paper cannot be used.

From DE-OS 19 33 362 a suspension developer for electrophotography is known from a Dispersion of 1 to 50 parts by weight of a toner in 1000 parts by weight of carrier liquid, the toner consists of pigment particles and two or more resinous layers covering the surface, of which the layer closest to the pigment is made of a resin that is insoluble in the carrier liquid, such as styrene or Styrene-butyl methacrylate copolymer, the outermost layer of something in the carrier liquid swellable resin, such as styrene-lauryl methacrylate copolymer or styrene-butadiene copolymer. However, it does not appear from this that this Suspension developer can be used for positively and negatively charged layers with special photoconductors is.

It is also known (DE-OS 14 97 152) for the production of copies on electrophotographic paper Devices with guide and movement devices for the paper strip, a charging, Use exposure and development stations, in which the development with the help of an immersion roller takes place and a squeegee roller and a dryer are provided for drying. Also from this script does not go into the special combination of back magnification with positive or negative charge Connection with a special photoconductor and a special suspension developer.

A photoconductor made from a polymer, in particular for electrophotographic purposes, has also been used Condensation product of formaldehyde or paraformaldehyde and at least one polynuclear carbocyclic, optionally substituted aromatics proposed (DE-OS 2t 37 288), the recurring unlinked units of the formulas

CH,

and or

wherein

Xi and X2 are identical or different and are hydrogen, Alkyl or alkoxyl with 1 to 4 carbon atoms each, halogen, preferably chlorine or bromine,

X3 and X4 are identical or different and are alkyl or Alkoxyl each having 1 to 4 carbon atoms, halogen, preferably chlorine or bromine and

π is an integer between about 6 and 10

mean,

consists.

However, this earlier application is not related to a specific use of the photoconductor with a back enlargement process and with special suspension developers.

The object of the present invention is to provide a microfilm re-enlargement method with which is a positive magnification on plain paper, both a negative and a positive Microfilm image is possible using one and the same suspension developer.

According to the invention, this object is achieved by a method for re-enlarging microfilm pre-

Cf rlm * / "* V»

tion of the enlarged image of the original on a positive (negative) original evenly negatively (positively) charged photoconductor layer, which is a polymeric condensation product of formaldehyde or paraformaldehyde and at least one polynuclear, carbocyclic aromatic as a photoconductor in the Contains mixture with at least one activator and a binder, the condensation product from recurring, non-networked units of the formulas

CH,

and or

CH,

wherein

Xi and X.2 are identical or different and are hydrogen, Alkyl or alkoxyl with 1 to 4 carbon atoms each, halogen,

X3 and X4 are identical or different and are alkyl, Alkoxyl each having 1 to 4 carbon atoms, halogen and

η is an integer between about 6 and 10

mean,

consists,

developing the electrostatic latent image with a suspension developer containing a toner a vinyl toluene-acrylate copolymer, a styrene-acrylate copolymer or a butadiene-styrene copolymer as a high molecular weight resin in a carrier liquid from a short chain Contains hydrocarbons with a kauri-butanol number below 30 and

the transfer of the toner image to an image receiving material.

This creates a method with which for the first time there is the possibility of any To obtain microfilm master positive copies by adjusting the sign of the corona voltage, whereby the same developer is used.

A photoconductor is preferably used, which is a polynuclear carbocyclic, chlorine or Contains bromine substituted aromatics. In particular, 3-bromopyrene is used as a polynuclear carbocyclic aromatic compound used.

It has proven to be advantageous if the photoconductor also co-condenses bianthryl units contains. The best results can be achieved if one uses a photoconductor that per mole Monomer basic building block contains 0.1 to 0.4 moles of activator. The photoelectric and mechanical Properties of the photoconductor are particularly good if the photoconductor is up to 200 percent by weight, based on the photoconductor, contains binder.

The photoconductor layers used according to the invention result in high contrast. It is believed that this is due to the high chargeability is due to these layers. In addition, the photoconductor layers are extremely sensitive, see above that can be copied much faster than in the process with zinc oxide layers.

The suspension developers have a resin with a high molecular weight from the group of vinyl toluene-acrylate copolymers, styrene-acrylate copolymers or butadiene-styrene copolymers on.

In order to achieve particularly good transfer of the toner image to the image receiving material, it is it is preferred to add a minor amount of a tackifying resin to the suspension developer. Preferred resins are α- or α-pinene, polyolefin, and heat-reactive synthetic hydrocarbon polymers or pentaerythritol ester of hydrogenated rosin.

It has proven very useful and is preferred that you use a suspension developer, the one Plasticizers for the resin with high molecular weight is added in particular come here as Plasticizers dialkyl phthalate, especially dibutyl phthalate, dioctyl phthalate, dimethyl phthalate, diethyl phthalate or chlorinated polyphenyls in question.

A special coloration or blackening can be achieved by using a suspension developer which contains a pigment compatible with the high molecular weight resin, in particular carbon black, with an average particle size of 25 μm.
A suspension developer with a suspension of 0.3 to 1.4 percent by weight of finely divided pigment with electrophoretic properties, 1.5 to 4.5 percent by weight of a high molecular weight resin, which is essentially in a liquid, short-chain hydrocarbon with a Kauri-butanol number of less than 30 Is insoluble, suspended in a liquid, short-chain hydrocarbon with a kauri-butanol number below 30, is preferred according to the invention. Suitable resins of high molecular weight are, for. B. a vinyl toluene-acrylate copolymer or a Ge mixture of heat-reactive synthetic hydrocarbon polymer with an iodine number of about 130 and butadiene-styrene copolymer.

It has surprisingly been found that the photoconductors mentioned for use in the Electrophotography can be charged equally positively and negatively, so that a method of the initially named type is created, with which by simply reversing the polarity of the charge on the photoconductor layer a negative as well as a positive microfilm produces a positive re-enlargement can be. In addition, it is possible to fix the transmitted image with normal power connection values perform.

A photoconductor layer is particularly preferred used on 2 g of 3-bromopyrene resin per 0.22 g of dicyanomethylene-2,7-dinitrofluorene as an activator and contains 1 g of polyester as a binder. With this photoconductor layer, copies of very good quality can be made large numbers can be produced without the photoconductor layer becoming unusable.

Particularly high-contrast re-enlargements are obtained if you look at the charge pattern on the Photoconductor layer with a suspension developer

4 (i developed as it is identified in more detail in the examples net is.

It is preferable to develop the charge image! in the presence of an outer, essentially perpendicular additional electrical elements running to the photoconductor layer tric field. The application of such an electric field is in the field of Electrophotography is known in principle. In the method according to the invention, the application brings however, the advantage that large ones are bright in the original

5 »Areas can then also be developed satisfactorily if the original is a negative, d. h if the big Areas of the photoconductor to be colored are completely or largely discharged.

To carry out the process, a Vorrich Device used, in which the photoconductor layer 1 according to the accompanying FIG gene pad is arranged and at a charging station 4 for uniform charging, a Beiich processing station 6, 7, '8 for an enlarged illustration of the dei Microfilm master 5 on the charged photoconductor layer at a development station 9 with developer electrode 11 for applying the suspension development lers 10 on the photoconductor carrying the charge pattern layer and at a transfer station for transferring the developed charge image to the image temp catch material! 13, is arranged to be movable past.

A required switchable Aufladungssta tion 4 is z. B. from US-PS 28 56 533 known

The invention is intended in the following on the basis of examples with reference to Figs. La and Ib further explained. There the re-enlargement process is schematically based on the various Station shown, which the photoconductor material 1 and the image receiving material 13 pass through. There is one Photoconductor path provided, which is initially guided between pairs of rollers 2 and 3 and up to one Charging and exposure station 6, 7,8 is moved. With the help of a through the photoconductor 1 in ι ο The charging station 4 moving in the direction of the arrow, the photoconductor layer is charged evenly. Simultaneously the back of this photoconductor layer is grounded. At the end of the charging process, when the charging station in the FIG. 1 a is the position shown in dashed lines, the imagewise exposure takes place. The microfilm original 5 is in this case with the aid of a lighting device consisting of a light source 6 and a condenser 7 illuminated and mapped with the help of optics 8. This creates the in a well-known way imagewise charge pattern.

Then the photoconductor material is moved for development through a tub 9, the one Suspension developer 10 contains a visible image of the original. The quality of the Development is improved in that the photoconductor layer 1 in the developer bath between the Plates 11 and 12 of a capacitor passed through will. The aluminum-coated underside of the photoconductor layer represents one capacitor plate 12 The other capacitor plate 11 is preferably a sheet metal with many evenly distributed perforations 15 (Fig. Ib). The flow of developer is kept very even through these passages. The distance of the electrode 11 from the photoconductor layer is about 0.1-3 mm, preferably about 1 mm. The electrode 11 is arranged in an isolated manner, whereby the required potential adjusts itself. If desired, the However, electrode 11 can also be connected to a voltage source. The use of a developing electrode In addition to being veil-free, it has two major advantages: On the one hand, the required Reduced the amount of light and thus the exposure time and / or the stress on the microfilm template can be reduced because the discharge of the photoconductor layer can be less. On the other hand, the Developing electrode especially in the production of back enlargements of negative ones according to the invention Originals have the advantage that the voltage of the developing electrode prevents the toner from settling on it; for In this case, which is most common in practice, a separate cleaning of the developing electrode can be dispensed with.

In order to achieve a transfer of the developed image to the image receiving material 13, it is necessary to remove excess suspension developer by squeezing it with rollers 18, 19. the Removal can also be done, for example, by blowing off.

The developed toner image on the photoconductor layer is then brought into contact with an image receiving material 13, for example a paper web, and transferred to the paper. Where necessary, the transferred toner image in the fuser 14 is fixed according to the invention it is preferred to carry out any fixing, but to heat the Biidempfangsmaterial such as paper prior to the transfer to a temperature between about 30 and 100 ⁰ C, as shown schematically by the radiator 17 is shown

Very high-contrast images were obtained with a suspension developer comprising the following ingredients exhibited.

Components lot Commercially available black pigment 13.25 g Commercial blue pigment 1.68 g Commercially available vinyl toluene / acrylic 58 g Mixed polymer Commercially available styrene / butadiene 63.6 g Mixed polymer Aromatic hydrocarbon, 151g Boiling range from 160 to 180 ⁰ C Aliphatic branched coals 7.561 hydrogen, boiling range 159-179 ° C

The above ingredients are with the exception of the aliphatic hydrocarbon mixed on a three-roll mill until they have become a homogeneous paste. This paste is made in 0.471 of said hydrocarbon dispersed on a roller mill Then 1.421 des aliphatic hydrocarbon is added and the mixture is stirred for 10 minutes. Finally, the Put concentrate in a grinder and grind for 30 minutes. The concentrate obtained is before the Use in a volume ratio of 1 part of concentrate

jo joined to 3 parts aliphatic! Hydrocarbon diluted.

The resin represents the toner particles. By squeezing off the excess suspension developer, a homogeneous, sticky layer in the form of an enlarged microfilm original is formed on the photoconductor layer, which adheres well to the image receiving material, but has only poor adhesion to the photoconductor layer.
To produce the photoconductor layer, the amounts of resin, activator and polyester specified in the following examples were dissolved in 25 ml of tetrahydrofuran and the solution was then filtered. The solution obtained is poured onto a circumferential conductive tape made of aluminum-vaporized polyester.

The resulting layer was about 3 to 4 minutes at 110 ° C in a drying cabinet to remove the Solvent dried The term used to denote the properties of the photoconductor layer the half-life represents the time within which the voltage for a given exposure has decreased to half the output voltage. It can be clearly seen from the figures that the chargeability of the photoconductor layers is somewhat better in the negative than in the positive range however, the values are so high that a microfilm re-enlarger delivers perfect copies with a switchable corona voltage

example 1

bo It was in the manner indicated with 2 g Pyrene resin, 0.56 g 2,4,7-trinitrofluorenone, 1.2 g polyester worked The photoconductor layer obtained could be charged to + 1200V and -1500V. the associated half-lives were 35 and 32 msec, respectively

Example 2

2 g of 3-bromopyrene resin, 0.56 g of 2,4,7-trinitrofluorenone and 1 g of polyester

processed. The photoconductor layer obtained was charged to + 1250V and -1600V. The corresponding Half-lives were 32 and 28 msec, respectively.

Example 3

2 g of 3-bromopyrene resin and 0.22 g of dicyanomethylene-2,7-dinitrofluorene were processed as indicated with 1 g of polyester. The shift was on +1250 V and then charged to -1400 V. The half-life was 15 and 10 msec, respectively.

Example 4

2 g of 3-bromopyrene resin, 0.25 g of dicyanomethylene-2,4,7-trinitrofluorene and 1 g of polyester were encapsulated as indicated to form a photoconductor layer. The layer went to + 1100V and then to -1300V charged, resulting in a half-life of 15 or 10 msec.

With the described photoconductor layers and the specified developer, it was possible to use one and the same microfilm master to produce positive and negative re-enlargements by using the charging station only the sign of the corona voltage was reversed.

In this way, a method is created with which for the first time there is the possibility of any Microfilm master positive copies by adjusting the sign of the corona voltage also then obtained when many hundreds of copies are made of one and the same photoconductor material.

A particular advantage of the method according to the invention is the possibility of sensitization for certain spectral ranges by selecting different activators or their combination. This makes it possible to optimally adapt the photoconductor to the lighting conditions in the copier device as well to adapt to the respective template (silver film, diazo film). For explanation are in F i g. 2 and 3 the spectral Sensitivity distributions of some activated layers with negative and positive charging indicated, the sensitivity being shown as the reciprocal half-life. The ratio of monomer-basic building block / activator is 1: 0.1 in all cases, this ratio only for comparison purposes was chosen, but does not indicate the optimal activation in each case from the multitude of available standing activators were selected four different ones, viz

I. 2,4,7-trinitrofluorenone
11. 9-Dicyanomethylene-2-nitrofluorene

III. 9-dicyanometkylene-2,7-dinitrofluorene

IV. 9-dicyanomethylene-2,4,7-trinitrofluorene

The corresponding curves are provided with the associated Roman numerals.

From Fig. 2 it can be seen that the activator 9-dicyanomethylene-2-nitrofluoren (curve II) is a special one causes high sensitivity in the range between 350 and 600 nm. One with this activator sensitized layer is particularly favorable for lamps that have their emission maximum in this area, such as z. B. fluorescent lamps or xenon lamps or xenon flash lamps. This layer is not just optimal adapted to the lamps, it is also particularly suitable for the re-enlargement of microfilms based on diazo, since the contrast between blackened and non-blackened areas in this area is the greatest is highest.

A shift in the spectral sensitivity in the long-wave range of the spectrum can be caused by activation can be achieved with 9-Dieyanornethylen-2,7-dinitrofluoren (curve III). This layer has a very high sensitivity both when using fluorescent lamps or xenon lamps as well as from Tungsten or halogen lamps. The spectral sensitivity distribution allows the back magnification of Silver halide and diazo microfilms.

A further shift in the spectral sensitivity in the long-wave range results from Use of 9-dicyanomethylene-2,4,7-trinitrofluorene (curve IV). This photoconductor layer is special sensitive when using tungsten or halogen lamps, as they have a high red content Lamps can be exploited. This layer is excellent for re-enlarging silver halide films suitable. As shown in FIGS. 2 and 3 can be seen further, is a very even sensitization over a wider range of the visible spectrum through the use of 2,4,7-trinitrofluorene (curve I) to achieve. Such a layer has a very favorable adaptation to the xenon lamp or xenon flash lamp.

In the case of negative charging (Fig. 3), the picture is essentially the same. The difference is only in the fact that in the short-wave range the sensitivity only begins noticeably at 400 nm, that on the other hand, in the long-wave range of the visible spectrum, the sensitivity is somewhat greater a suitable choice of lamps, the emission of which covers a wide range of the spectrum, can be at The same sensitivity can be achieved with negative charging as with positive charging.

A particular advantage of the method according to the invention is that an almost 100 percent Transfer of the toner image from the photoconductor layer onto plain paper is therefore achievable at most, a little cleaning is still required, which leads to a reduction in mechanical stress A paper that is preferably used is characterized by high suction power and surface smoothness as well as low air permeability and has a suitable rigidity

For this purpose 3 sheets of drawings

Claims (1)

Patent claims: 1. Process for the re-enlargement of microfilm originals, characterized by the combination the enlarged image of the original on a positive (negative) original evenly negatively (positively) charged photoconductor layer, which is a polymeric condensation product of formaldehyde or paraformaldehyde and at least one polynuclear, carbocyclic aromatic as photoconductor in a mixture with at least one activator and a binder, the condensation product from recurring, non-networked units of the formulas