DE2336338C3 - Either positively or negatively chargeable electrophotographic recording material - Google Patents

Description

Copolymer with 50 to 95 percent by weight photographic recording material, the optional acrylic acid ester units, 1 to 5 percent by weight is positively or negatively chargeable. There were units of an unsaturated carboxylic acid and 0 to extensive investigations with regard to the Er-49 Weight percent units of any mono-30 targeting the ability to selectively charge the contains mers and a polymer. electrophotographic photosensitive layer

The known method for electrophotogra- carried out, the influences of binder and The phical production of images includes the following substrates have been tested, the stages: (1) electrostatic charging of a light- There are numerous types of binder resins

sensitive photoconductive layer, (2) imagewise 35 for the production of electrophotographic Exposure to form electrostatic photosensitive layers using latent images, (3) development by means of charged zinc oxide known. Typical examples of such colored toner particles. When the known binders are exposed to light, silicone resins are different charged photoconductive layer, the charge goes into polyester resins including alkyd resins and the exposed areas due to the 40 different vinyl resins such as vinyl acetate and poly produced therein Conductivity lost while the unexposed acrylate and polystyrene.

areas retained the charge, which means that acrylic resins have also been used as binding agents.

Electrostatic medium resin for zinc oxide corresponding to the original picture for the production of eleklatentes Image obtained by means of toner particles, trophotographic recording materials an opposite electrostatic charge 45 is set. Acrylic resins generally include those through wear, is developed. The toner particles can polymerize acrylic acid, methacrylic acid, as a powder developer or as dispersed acrylic acid esters, methacrylic acid ester ^ derivatives sion in a highly insulating liquid used the ester, mixtures of monomers and styrene, will. Styrene derivatives and other monomers with poly-

In general, the electrophotographic 5 ° merizable vinyl group produced resins, photosensitive layer by means of a corona agent Charge from 6000 to 8000 volts, with dispersing properties of the zinc oxide, the Hafeine DC high voltage source for application properties on the substrates, the dung. By changing the poles, mechanical properties, the size of the charge, the direct current source a positive or a negative 55 the sensitivity of the light-sensitive layers, tive charge can be applied. the moisture resistance, the heat resistance

It was found that if a common elec- tricity, the monomer composition and the polytrophotographic light-sensitive material degree of merization with regard to achieving the gemal was positively charged, satisfactory reproduction desired electrophotographic properties ductions could be made while when 60 examined. So are different types of acrylic glass same electrophotographic photosensitive resins as binders for electrophotographic Material has been negatively charged, not reproducing recording materials in Japanese patents could be obtained. Therefore publications 6 395/66, 6 392/59, 6 393/69, charge to be applied depending on the characteristic 6 394/69, 17 316/69, 11636/71 and 18 116/71 Behavior of the electrophotograph.

phischen light-sensitive material can be selected For example in DT-AS 15 97 862 a styrene,

the. Containing acrylic acid methyl ester and acrylic acid

It is known that when using selenium copolymer as a binder for ZnO in an electronic

3 4

Photographic recording material described- Original of a positively charged electrophotograph Furthermore, DT-OS 18 15 472 describes the phical recording layer.

tion of an acrylic resin with a Skurewwert 15, With reference to Fig. 1, the surface of the

α the following components, namely butyl electrophotographic photosensitive layer 3 vlat styrene, methyl acrylate and acrylic acid, um- 5 initially uniformly negative by means of the corona ⁰ Rt as a binder for zinc oxide in electrophoto-discharge device 2, which is connected to an electrical recording material. Finally, direct current high voltage source 1 is connected, the DT-OS 210 158 the use of loaded. The negatively charged electrophotographic η is tvl or ethylhexyl methacrylate or acrylate corresponds photosensitive layer 6 then through an I iZnden copolymers as binder for a positive original electron-io 4, if necessary by a Käonaphisches recording material. Lens S, exposed, the exposed areas of the

in the publications mentioned above, layer 6 lose their charge and the unbelicn-K, however, there is no indication that these areas retain their charge. Using these tVe acrylic resins as a binder for ZnO in an optional manner, an electrostatic latent bud of a positive or negatively chargeable electrophoto-negative charge is obtained on the layer. The electron! "HUehen recording materials used trophotographische recording material 7 wira ^ß A *! You can then use a positively charged toner to

Either positively or negatively chargeable electrically, the toner in the image areas being attracted by electrostatic attraction. Here, Sch in Japanese Patent Publication a °, the developed positive image is obtained Ϊ -VlO wherein the use of a vinyl chloride With reference to FIG. 2 is made using a

Vinvlacem copolymers is indicated, and in the usual electrophotographic photosensitive See Patent Publication 40 133/70, wherein recording layer containing a positive copy through ColeHer from the series of cadmium compounds has a certain charge, for example a negative one Ln are described. * 5 charging, can supply, the electrophotographic

⁸ However, also in these publications, paper 3, as shown in FIG. 1 shown, negative gdadenjiei ι ί, «, satisfactory way indicated, after which an exposure of the electrophotographic paper S ^" oil "negatively ^ chargeable electro- or recording material 6 with -nem negative recording material with an original 4, possibly through a lens , 5, ver ^ * ^ of high quality , ^^^^^^ S ^^ f

^We Mf ⁿ _g abe of the invention is therefore to provide parts, as shown in Figure 2, an optional oositiv or negatively chargeable characteristic properties lekUhotographischen recording material retained with their charge ™ ^^

Binder, a polystyrene with a molecular 55 Lms ^^ 5, the ^ ^ ^^ lose _their ih t 5000 contains jnendei »^ eiie, Jα. π _i l ih Ldg

Binder, yy ^^ l ^ ^ ^^

Contains weight less than 5000. jnendei »^ eiie, Jα. π _{büd {reien Tei} l _e its charge

The invention is formed below using the ^^^^^ '^ _latent image

Drawing explained in more detail: ^ ¹ "' _fn ■ _{di charge} on the picture-

Fig. 1 illustrates the manufacture of a will. In "•" em fail "ι u β ^

Positive copy by exposure with a po »Uven«. re.en Γ. ej ^^^ w ^ m _$

Original of a negatively charged electrophotogra posm g ^^ _{used This is the opposite} .

phical recording layer; "u < en" working method shown at

Fig. 2 illustrates the preparation of a salt to the "n t ig. feg ^ _Ε ^. ^ _

Positive copy by exposure with a negative welch_er en negative ge a ^ _{1 an osi} . Original of a negatively charged electrophotogra- * ₅ ^ ^ »« ducks ^ ldes ^^ ^ ^ ^

_ph . _ch en Aufze, chnun _S hich; ^^ _{Joner w} . _{that shown in FigA}

Pn ^ ivkooie IZ ^ h exposure used with a negative working method.

The above embodiment is electric potential thereof upon exposure just an example of the practical use of light to obtain applied electrical potential of the electrophotographic recording material. However, they fall by means of the potential characteristic the. Invention, the optionally positive or curve determined results not always with the can be charged negatively. The applicability- 5 real properties of electrophotography and usefulness of the electrophotographic phical images related to the practical However, as can be seen, recording material can be obtained. When examining the self-very large. shafts for either positive or negative

In accordance with the invention, it has been found that charging an electrophotographic record is optional positive and negative chargeability of ionizing material becomes just that mentioned above the amount of acrylic ester in the acrylic resin compositions, the difference in properties is noticeable. When is determined. For the optionally positive or e.g. an electrophotographic photosensitive negatively chargeable electrophotographic layer on - 500 V negatively charged and on Drawing materials according to the invention, it is + 500 V is positively charged, and at the same time the damping is necessary, that the copolymer component of the 15 tendency towards exposure in both cases fully binder 50 to 95 percent by weight and preferably always the same, d. i.e., the potential characteristic curve in 70 to 90 percent by weight acrylic acid ester in both areas from the zero potential baseline contains units. Furthermore, if 1 to 5 percent by weight is symmetrical, it is often observed that when of the mixed polymer from units of an unsaturated negative charge of the layer a sharp electroting Carboxylic acid obtained with the acrylic ester mixed "photographically developed image that is polymerizable, exist, for example acrylic does not show any haze on the non-image areas, acid, methacrylic acid, fumaric acid, maleic acid, while with a positive charge a matt Itaconic acid, maleic anhydride, itaconic acid - electrophotographic image with heavy haze anhydride, and monoesters of the above listed on the non-image areas is obtained. In this ten divalent acids. The remaining units of the * 5 case can be such an electrophotographic Copolymer can of any with acrylic layer not as either positive or negative ester copolymerizable monomers derived from chargeable electrophotographic layer be, for example methacrylic acid esters ^ like Me, even if this layer is negative or positive ethyl methacrylate, ethyl methacrylate, butyl methacrylate can be charged to the same amount of charge Od. Like., methacrylic ester derivatives, such as hydroxyethyl 3 ° can.

methacrylate, glycidyl methacrylate or the like, styrene, It comes *, sometimes it happens that, if the content of the

Styrene derivatives, such as methyl styrene, chloromethyl styrene, methacrylic acid esters within the above

or the like, and similar materials. given electrophotographic photosensitive

Examples of usable acrylic acid esters are layer becomes larger, the amount of charge of the electro-

Ethyl acrylate, propyl acrylate and butyl acrylate. You 35 static charge on the layer both in the case of the

can be used individually or in combination negative charge greater than the positive charge

the. The choice of the acrylic acid ester or the acrylic is used as an electrophotographic light em-

acid ester is made up of the desired mechanically sensitive layer, which consists of an acrylic acid ester

Properties determined. resin was made on the basis of the

As can be seen from the following examples and 40 of the characteristic electric potential curve, comparative examples, the results obtained when used go. However, in one of the methacrylic acid esters, instead of the acrylic acid-like case, an electrophotographic image of the ester may retain the properties of optional positive good quality to some extent or lose negative chargeability. As examples, when the layer is practically treated in an electrophoto for methacrylic acid ester, which is treated as a further component 45 graphic process in the case of the negative in addition to the acrylic acid esters in the mixed charge of the layer, while the polymerized acrylic resin are usable, the image qualities are poor due to dullness de; listed methyl methacrylate, ethyl methacrylate, picture and the formation of a strong haze in propyl methacrylate and butyl methacrylate with vari- ous case of the positive charge of the layer coloring,
render chain length of the alkyl group and lauryl 50 However, the use of methacrylic acid methacrylate with a longer chain length in the ester in the context of the invention is not excluded from the alkyl group than in the case of methacrylic acid esters. If these sen. That is, if 50 to 95 V · of the acrylic acid ester amount of the methacrylic acid ester exceeds 50 percent by weight and 1 to 5% of one with the acrylic acid ester copolj, but the properties of visible organic acid as a component of the optional positive or negative charging 55 for the acrylic acid copolymer, which as electrophotc availability impaired graphic light-sensitive or photoconductive

As used herein, »optionally positive layer is used in accordance with the invention, eir

or negatively chargeable «describes the ability that can be set, methacrylic acid esters as Res

be used for the copolymer for both positive and negative electrical components static charge and after imagewise exposure 6 ° if no deterioration in both directions

and developing with a toner material sharp gene chargeable properties of the photosensitive

Images without fog can be obtained. Enter shift. Furthermore, other compt

As is known, the electrical potential characteristic curve is other than the methacrylic acid ester, for example

an electrophotographic photosensitive wise derivative of acrylic acid esters or Methacrj Recording material a measure to test 65 acid esters, styrene and styrene derivatives as residual koi

of the characteristic properties. Used by the potential characteristic for the acrylic acid copolymer

curve can be used for the charge of the light-sensitive. Especially when using a Mon

borrowed layer and for the damping state of the meren with high electrical insulating properties

wmm

substantial deterioration in the properties, which can also be charged negatively, ce.

We! Trrhin ^e it is going to be insane, the case of the emelun ^ on dectrophotographic

ilPifii Negative charge test

Layer can be increased, thereby

shows when the shift
imprecise images «
resources of low

They invented 35 under

_and

Posi toner as _creating a

acid, methacrylic acid, Acrylsaureeje acid ester and derivatives of such monomers

The following examples serve to further elucidate the invention.

Example 2
e the different amounts of ethyl

Maleic anhydride and

listed

^6O

_Gnm d-

fabric sensitizer

Sound waves mixed, and

Surface of an electrophot

paper, the surface of which e

lune had been subjected,

Stick (stick-shaped ** ™ E £ "üteag> -

coiled fine copper wire) rn emei ^ _

amount given as a solid, of 25 g hurry,

had read
more than
·. 65 ratio of

with on the '

ng
_{so that}

eu ™ ethyl acrylate r while, if it is used as 50

ma uiu »—Je, and those it became quantifiable on the bare areas.

609629/283

Table I.

ίο

sample
1

Monomer

composition,

Weight percent

Ethyl acrylate 0

Butyl methacrylate 70

Methyl 26

methacrylate

Methacrylic acid 2

Maleic acid 2

anhydride

20th
50
26th

35 35 26

2 2 50
20th
26th

2 2

2 2

95 0 0

2.5 2.5

Test results with no veil, no veil, no veil, no veil, no veil, no veil

Negative charge properties

good picture quality

high density

good picture-good picture quality

high density slightly lower good image - good image - good image quality quality quality

Density about density low- density low _ the same as with slightly lower

Density than in sample 3 than in the

Samples 3
and 4

the samples and

Test result
Positive charge properties

Picture not
decipherable

Image difficult, rigorous, veil, barely blurred

of the picture minor no haze, no haze, haze, picture picture quality picture quality decipherable good good, low

density

Example 3 Tables

Six kinds of copolymers were prepared using methyl acrylate or butyl acrylate in place of ethyl acrylate as the monomer component of the copolymers of Example 2, and the same test as in Example 2 was carried out on the samples prepared using the copolymers as binders. From the data, it was found that the samples showed practically the same tendency as in the case of using ethyl acrylate, that is, when the ratio of the acrylic acid ester component was higher than 50% by weight, the sample showed good positive charging properties, while when the ratio of the acrylic acid ester was lower than 50% by weight, the positive charging properties of the samples were decreased.

Example 4

60

A series of copolymers having the monomer compositions as shown in Table Π, that is, copolymers having various proportions of styrene, were prepared and the same procedure as in Example 1 was carried out using the copolymers as binders for the electrophotographic photosensitive layers

70

11th

15th

Monomer component
(Weight percent)

Ethyl acrylate 70 Methyl acrylate 21

Styrene 5

Methacrylic acid 2 Maleic acid 2

anhydride

From the data, it is found that the image density was higher than that of Sample 2 in Example 2 without that both positive and negative charging properties of the samples worsened and the image density increased accordingly as the ratio of the styrene was increased.

Example 5

A resin having the same composition as Sample 10 of Example 4 was made with a low molecular weight polystyrene in which

Table III indicated, based on the weight Misehverhaltnissen mixed and samples using the resulting mixture as a binder for the light-sensitive layers made of the same elcktrophotographischen hs ^r; the results are also included in the table.

Table III sample 12th 13th 14th 15th 16 11th Harz after 8/2 6/4 4/6 2/8 0/10 Sample 10 10/0 Polystyrene from low Molecular Image sharp, Image sharp, Image sharp, Image weak Image weak Weight Image sharp, Density higher Denser higher Density low blurred, blurred, test Density usual than at than at docile higher than Density high Density low Negative- Sample 11 Sample 12 at sample 12 Cargo own Image sharp, Image sharp, Veil ge stronger Picture blurred, societies Image sharp, Density higher Density higher forms, image Veil, image Density low test density than at than at slightly blurred Positive charge normal Probell Sample 12 blurred properties

It can be seen from these values that when the mixing ratio of the polystyrene is increased from low molecular weight the image density increased, while if the content of polystyrene was low Molecular weight was higher than 50 weight percent, haze on the bare areas when Positive charge property tests were formed, and the image became dull.

Example 6

The procedure of Example 5 was followed using other commercially available polystyrene eggs of low molecular weight repeated. Dii the results obtained were practically the same as those of Example 5.

1 sheet of drawings

Claims (1)

as a photoconductor, the electrophotographic light sensor Patentansptuch: ^W-sensitive material provided with a positive charge must be, while when using ZnO optionally positively or negatively chargeable binder layer, the charge with negative polyelectrophotography Recording material 5 rity must be granted. It is assumed that with a ZnO binder layer, which acts as a binder, this different behavior depends on whether medium a mixture of a mixed polymer of the photoconductor belongs to the P-type or N-type, with 50 to 95 percent by weight acrylic acid ester- When using such a conventional elec- units, 1 to 5 weight percent units of a trophotographic photosensitive material, unsaturated carboxylic acid and 0 to 49 weight-i ° that only with a single specific, e.g. percent units of any monomer negative, charge can be charged, must be and contains a polymer, thereby achieving a positive-positive copy with a toner indicates that the binder can be used as a poly- a positive charge while merisat 10 to 50 percent by weight, based on a toner with a negative charge to achieve the total weight of the binder, one poly 15 one negative-positive copy are used styrenes with a molecular weight below 5000 must. In the same way, a negatively charged contains. Toner to achieve a positive-negative copy and a positively charged toner to achieve a Negative-negative copy in an electrophotographic 20 phischen material, which can only be positively charged, are used. So must according to the previous practice of the toner used changed The invention relates to an optional positive or, or it must two specific Einrichtunnegativ chargeable electrophotographic up gen JeWeI be provided with a positive toner S ₁ and with a recording material having a ZnO-binder "5 negative toner. Layer which, as a binder, is a mixture of an