GB2030307A

GB2030307A - Black Line Diazo Copying Material

Info

Publication number: GB2030307A
Application number: GB7843328A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-09-18
Filing date: 1978-11-06
Publication date: 1980-04-02
Also published as: JPS5540471A; DE2848488B1; JPS579055B2; GB2030307B; FR2436417A1; BE871582A; FR2436417B1

Abstract

A photosensitive layer on a paper substrate, or a photosensitive solution, useful in black line diazo copying, contains certain high and medium speed blue coupling components, certain high and medium speed yellow coupling components and a certain medium speed brown coupling component together with one or more diazo compounds and can give high speed copying with neutral black tone in both high and low density areas without the necessity to include a high speed brown coupling component.

Description

SPECIFICATION High-speed Two-component Type Black Line Diazo Copying Paper The present invention is concerned with highspeed two component type black line diazo copying and provides such copying paper and corresponding photosensitive liquid. Such copying paper may be provided, according to the invention, with photosensitivity similar to that of blue line high-speed diazo copying paper and with both the high density areas and the low density areas having a neutral black image.

In general, in black line diazo copying paper a blue coupling component, a yellow coupling component and a brown coupling component are jointly used, the mixing ratio of these components being empirically decided by trial and error. It is well known to select as such coupling components, components which have substantially the same coupling speeds so as to form neutral black both in areas of high density and areas of low density in the image. When the photosensitivity of black line copying paper is low, ammonia works effectively at the time of development and the paper is developed at a high pH, and differences in coupling speeds between the coupling components are not substantial so that, at low density areas, rarely does any of the coupling components have enough priority over the other two to give an overal colour other than neutral black.However, a highly photosensitive paper is generally subjected to a low pH during the initial stages of development, and differences between the coupling speeds of the various coupling components are sufficiently pronounced that neutral black cannot be obtained at low density areas. It may generally be regarded as impossible to select a combination of coupling components, which have identical coupling speeds at both high pH and low pH.

I have now found that it is possible to give a neutral black tone over an entire image by forming a high density area comprising a combination of coupling components whose coupling speeds are substantially the same at high pH, and also providing a second combination of coupling components whose coupling speeds are substantially the same at low pH to form a neutral black image at a low density area, and surprisingly I have found that the colour controlling effect of a brown coupling component is not so substantial so that it is not necessary to provide two kinds of this component, for high pH and low pH, but that in practice only one kind of this component can be sufficient.

In my invention as photosensitive layer on paper substrate, or as photosensitive liquid, I use certain diazo compound(s), certain high and medium speed blue coupling components, certain high and medium speed yellow coupling components and a certain medium speed brown coupling component.

As diazo compound in the present invention, at least one compound of the general formula

(wherein R is an alkyl group having 1 to 4 carbon atoms, R1 and R2 are the same or different substituted or non-substituted alkyl, aralkyl or cyclo-alkyl groups or R, and R2 together form a heterocyclic group with the nitrogen atom to which they are both joined, and X is an anion) may be used and these compounds have sufficiently high photosensitivity.

Examples of such useful diazo compounds are:~ 1 -diazo-2,5-diethoxy-4-morpholinobenzene chloride, 1 -diazo-2,5-dibutoxy-4-morpholinobenzene chloride, 1 1-diazo-2,5-dibutoxy-N,N-dibutylaniline chloride and 1 -diazo-2,5-diethoxy-N-benzyl-N-ethylaniline chloride.

As blue coupling component becoming a main body of an area of high density there is used in the present invention the compound:

which has a medium coupling speed.

As blue coupling component becoming a main body of an area of low density, one or more high speed coupling compounds of the general formula

(wherein R3 denotes -H, an alkyl group having 1 to 4 carbon atoms or a halogen atom, R4, denotes -H, -(CH2), OH or-(CH2)#

wherein n is 2, 3 or 4, R5 and R6 may be the same or different alkyl group of 1 to 4 carbon atoms or may together form a heterocyclic group with the nitrogen atom to which they are both joined) is appropriate. Specific examples of such compounds are: 2-hydroxy-3-naphthoic acid diethylamino ethyl amide, 2-hydroxy-3-naphthoic acid morpholino propyl amide, 6-butoxy-2-hydroxy-3-naphthoic acid morpholino propyl amide, and 2-hydroxy-3-naphthoic acid amide.

As yellow coupling component becoming a main body of an area of high density the medium coupling speed compound.

is preferred but the compound:

may also be used.

As yellow coupling component becoming a main body of an area of low density one or more high-speed coupling compounds of the general formula:

(wherein R denotes -CH3 or -C2Hg are appropriate, that is to say one or both of the compounds:

and

As the brown coupling component, the medium coupling speed compound of the formula

is appropriate. Because this compound has a coupling speed at low pH close to the coupling speeds of the specified high speed blue and yellow coupling components this compound may participate in formation of either a high density area or low density area.

The weight ratio of a coupling component becoming a main body of areas of high density i.e.

component II or IV to a coupling component becoming a main body of areas of low density i.e.

component Ill or V is preferably 1 0:2 to 4.

In the preparation of a photosensitive liquid, such additives as solubiiizer(s), stabilizer(s), accelerator(s) and spreader(s) as are generally used may be used in this invention which also provides such photosensitive liquids comprising a mixture of the diazo compound and coupling agents specified above.

The following Example illustrates one embodiment of this invention.

A photosensitive liquid of the following composition was prepared, applied to a base paper and dried.

Water 75 ml Citric Acid 3 9 Isospropyl alcohol 1 ml Caffein 1 g Allylthiourea 2 9 Coupling component II 1 g Coupling component lil 0.3 g (2-hydroxy-3-naphthoic acid diethyl aminoethylamide) Coupling component IV 0.6 g Coupling component V(R=CH3) 0.2 g Coupling component VI 0.1 g Diazo compound 1 2.5 g (1 -diazo-2,5-dibutoxy-4-morpholino benzene chloride) Thiourea 2 9 Zinc chloride 2.5 g Methylene blue 0.002 g Saponin 0.01 g Added water to 100 ml Then copying paper thus obtained, after exposure to an image, was developed with ammonia vapour in accordance with the usual practice. A black image, both the high density area and the low density area of which were neutral, was obtained. The printing speed of this copying paper was the same as that of highspeed blue line copying paper and it was seen that the density was sufficiently high to be of practical value.

Claims

1. High-speed black line diazo copying paper comprising a photosensitive layer containing diazo compound, blue coupling components, yellow coupling components and a brown coupling component, on paper substrate, the photosensitive layer containing, I at least one diazo compound of the general formula:

(wherein R is a (C1 to C4)-alkyl group, R, and R2 are the same or different substituted or nonsubstituted alkyl, aralkyl or cycloalkyl groups or together form a heterocyclic group with the nitrogen atom to which they are both joined and X is an anion); II as a blue coupling component, the compound:

Ill as another blue coupling component, at least one compound of the general formula::

(wherein R3 is -H, a (C1 to C4) alkyl group of a halogen atom, R4 is-H, (CH2)nOH or~(CH2)n

wherein n is 2, 3 or 4, and R5 and R6 are (C1 to C4)-alkyl groups or together form a heterocyclic group with the nitrogen atom to which they are both joined: IV as a yellow coupling component, one or both of the compounds:

V as another yellow coupling component, one or both of the compounds of the general formula:

(wherein R is -CH3 or -C2H5); and VI as brown coupling component the compound:

2. A photosensitive liquid comprising a mixture of components I, lí, III, IV and V as specified in Claim 1.

3. Paper as claimed in Claim 1 or liquid as claimed in Claim 2 wherein the weight ratio of component II to component Ill and/or component IV to component V is or are 10:2 to 4.

4. Photosensitive paper as claimed in Claim 1 or photosensitive liquid as claimed in Claim 2 substantially as described in the foregoing Example.