Electrostatic image developing toner for use in heat-roller fixing

An electrostatic image developing toner useful for the formation of a toner image by electrophotographic process which employs a heat-fixing method by the use of a heat roller under pressure, wherein said toner comprises as the essential constituents a nonlinear polymer, a low-melting polymer which has a melting point of from 50.degree. to 130.degree. C. and which is incompatible with said nonlinear polymer, a copolymer composed of a segment polymer which is at least compatible with the above nonlinear polymer and a segment polymer which is at least compatible with said low-melting polymer and a coloring agent.

FIELD OF THE INVENTION 
The present invention relates to an electrostatic image developing toner 
for use in developing electrostatic latent images formed in the 
electrophotographic process, electrostatic printing process, electrostatic 
recording process, and the like, and more particularly to an electrostatic 
image developing toner for use in heat-roller fixing. 
BACKGROUND OF THE INVENTION 
For example, there are various methods conventionally known as the 
electrophotographic process (reference can be made to U.S. Pat. No. 
2,297,691, and the like). 
Generally speaking, an electrostatic image carrier comprised of a 
photoconductive photoreceptor is charged and imagewise exposed to thereby 
form an electrostatic latent image thereon, the electrostatic latent image 
is then developed by either a two-component-type developer comprised of a 
toner and carrier or a one-component-type developer comprised of a 
magnetic material-containing toner alone, and the developed toner image is 
transferred onto a support such as a sheet of copying paper and fixed 
thermally or under pressure, whereby a visible image is formed. 
As for the toner fixing method, various methods have been used to date. 
Above all, the heat-roller fixing method is most useful. The heat roller 
fixing method is one in which a support, such as a sheet of paper, 
carrying a toner image is transported being in contact with a heated 
roller to thereby fix the toner image to the support. This method is 
advantageous in respect of safety and also in the energy saving because it 
reduces the loss of heat. 
However, where the heat-roller fixing method is used, at the time of the 
heat roller fixing, the toner in the molten condition is to come into 
contact with the surface of the heat roller, but, in any of conventional 
toners, its adhesiveness in its molten condition is so high that part of 
the molten toner is transferred and sticks onto the surface of the heat 
roller, resulfing in a trouble, the so-called offset phenomenon, that the 
toner on the heat roller is then retransferred onto and stains the 
subsequenty copying paper. 
Further, in recent years, the development of a toner capable of being fixed 
at a much lower temperature than ever before is strongly desired to meet 
the demand for the realization of high-speed copying apparatus or the 
miniaturization of copying apparatus. That is, in a high-speed copying 
apparatus, when copying is performed in successsion to make a large number 
of copies, the heat of the heat roller is absorbed by sheets of copying 
paper, so that the resupply of heat cannot overtake the necessary amount 
of heat therefor, and as a result the heat roller's temperature becomes 
lowered, tending to cause a fixing trouble. In a small-size copying 
apparatus, the apparatus needs to be of an energy-saving and compact type 
by reducing the capacity of the heater of the heat roller thereof, but if 
the capacity of the heater is reduced, it takes time to heat up the heat 
roller, so that a lengthy warming-up time is required or the resupply of 
heat cannot overtake the necessary amount of heat for running copying 
operations, resulting in the lowering of the heat roller's temperature to 
tend to cause a fixing trouble. 
Accordingly, in order to solve these problems, a toner which is capable of 
being fixed at a temperature lower than that heretofore in use and 
excellent in the antioffset property is required. 
A conventional technique of accomplishing fixation at a low temperature by 
using a binder for a toner a crystalline polymer having a melting point of 
50.degree. to 150.degree. C. and an activation energy of not more than 35 
kcal/mole for its fluidization is disclosed in, e.g, Japanese Patent 
Examined Publication No. 36586/1982. However, where this toner is used in 
the heat-roller fixing method to form an image, there occurs a problem 
that the toner is inadequate in the antioffset property. Therefore, in 
order to prevent the occurrence of the offset phenomenon, copying 
apparatus needs a means to supply an oil for providing mold releasability 
to the surface of its heat roller, but it leads to the problem that the 
apparatus becomes complex. In addition, the crystalline polymer is so soft 
that the toner and the carrier are hardly mixed uniformly, and as a result 
the triboelectrification property of the toner becomes unstable, leading 
to the problem that the resulting toner image is not clear. Further, the 
crystalline polymer constituting the toner is liberated to be transferred 
and sticks onto the carrier grains or to the photoreceptor's surface; 
i.e., the so-called `toner filming` phenomenon occurs, thus leading to the 
problem that it adversely affects the image formation. Furthermore, the 
use of the crystalline polymer deteriorates the durability of the 
resulting toner. 
As is described in, e.g., Japanese Patent Examined Publication No. 
23354/1976, the use of a resin of a cross-linked structure is known as a 
technique to improve the antioffset property. However, if an attempt is 
made to obtain an adequate antioffset property by increasing the 
cross-linking degree of the resin, then the fixing temperature increases 
to deteriorate the fixability at a low temperature, whereas if the 
cross-linking degree is lowered in order to obtain an adequate fixability 
at a low temperature, no adequate antioffset property can be obtained; 
after all, in the resin of the cross-linked structure it is difficult to 
satisfy both the antioffset property and the fixability at a low 
temperature. Providing the apparatus with a means to supply an oil for 
giving mold releasability to the surface of the heat-fixing roller is 
known as a technique to prevent the occurrence of the offset phenomenon, 
but this technique is disadvantageous in respect that the oil supply 
mechanism-provided copying apparatus is complex, and the oil is heated to 
be evaporated to give out a stench to mar the environmental sanitation. It 
is therefore desirable that the toner in itself, without the aid of an 
external means, have a high offset-producing temperature and a low minimum 
fixation temperature, thus having adequate antioffset property and 
fixability at a low temperature. 
Owing to such circumstances, we have been continuing our investigation of 
techniques for obtaining adequate antioffset property and fixabiity at a 
low temperature of the toner by using a resin formed by mixing a resin of 
the cross-linked structure with a low-melting resin. 
It has now been found, however, that there is an additional problem in such 
techniques; i.e., in such techniques, uniformly mixing the resin of the 
cross-linked structure with the low-melting resin is essential in order to 
obtain an adequate antioffset property and fixability at a low 
temperature, but it is difficult to mix such resins uniformly, and 
consequently the difficulty brings about various problems: 
Firstly, due to the not-uniform mixing of both resins, the low-melting 
resin tends to be liberated, so that in the toner the softeness 
characteristic of the low-melting resin appears largely, bringing about 
toner's agglomeration inside the developing device; the so-called blocking 
phenomenon, and the toner-carrier triboelectrification tends to become 
inadequate, and the fluidity of the resulting developer is lowered, thus 
bringing about the problem that, eventually, the obtained copy is of a 
fogged, unclear image. 
Secondly, in repeatedly making copies of an image, a phenomenon that the 
liberated low-melting resin is transferred onto and sticks to carrier 
grains and the phtotreceptor's surface; the so-called toner filming 
phenomenon, occurs at an early stage, and the consequently obtained image 
shows a low image density with much fog, and thus is an obscure image. 
Thirdly, due to the not-uniform mixing of both resins, it is difficult to 
disperse a coloring agent uniformly into a mixture of them, thus resulting 
in a copy image being deteriorated in the color tone. 
Thus, it is the status quo that there has still not been obtained any 
satisfactory toner for use in heat-roller fixing, which has adequate 
fixability at a low temperature and antioffset property, excellent 
antiblocking and triboelectrification properties, and excellent color 
tone, and which is capable of forming a fogless, clear image, and also 
capable of repeatedly forming excellent copies of an image. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an electrostatic image 
developing toner for use in heat-roller fixing which satisfies all the 
following requirements: the toner shall (1) have adequate fixability at a 
low temperature, (2) have an adequate antioffset property, (3) have an 
excellent antiblocking property, (4) have an excellent 
triboelectrification property, (5) enable to obtain an excellent 
color-tone image, (6) enable to obtain a fogless, clear image, and (7) 
enable to obtain a number of repeated excellent copies of an image. 
The present invention specifically relates to an electrostatic image 
developing toner for use in heat-roller fixing which comprises the 
following Constituents (A), (B), (C) and (D) as the essential Constituents 
thereof: 
Constituent (A): A nonlinear polymer, 
Constituent (B): A low-melting polymer which is incompatible with 
Constituent (A) and whose melting point is from 50.degree. to 130.degree. 
C., 
Constituent (C): A copolymer formed by the chemical combination of a 
segment polymer which is at least compatible with the above Constituent 
(A) and a segment polymer which is at least compatible with the above 
Constituent (B), 
Constituent (D): A coloring agent. 
DETAILED DESCRIPTION OF THE INVENTION 
Since the above polymer as Constituent (A) and the polymer as Constituent 
(B) are incompatible with each other, it is difficult to obtain a 
uniformly mixed toner from these polymers alone. The toner of this 
invention, however, comprises also a copolymer as Constituent (C) 
comprised of two segment polymers that are compatible with Constituent (A) 
polymer and Constituent (B) polymer, so that in this toner the copolymer 
as Constituent (C) is coordinated at the boundary between Constituent (A) 
polymer and Constituent (B) polymer to play, so to speak, a 
surfactant-like role, and consequently the Constituent (B) polymer comes 
to be uniformly micorscopically dispersed and mixed into the Constituent 
(A) polymer. As a result of the respective polymers being uniformly 
dispersed and mixed, the dispersiblity of a coloring agent into them also 
is improved. 
Accordingly, this toner displays both the excellent property based on the 
nonlinear polymer as Constituent (A) and the excellent property based on 
the low-melting polymer as Constituent (B); namely, the polymer as 
Constituent (A) is linear and hard and plays chiefly a role of increasing 
the triboelectrification property and durability of the toner, and at the 
same time a role of increasing the antioffset property by having the toner 
show a high viscoelasticity to have a high mold releasability even when 
heated to be molten by the heat roller. The polymer as Constituent (B) has 
a melting point of from 50.degree. to 130.degree. C. and plays chiefly a 
role of increasing the fixability at a low temperature of the toner, but 
this Constituent (B) polymer, since it is soft, tends to lower the toner's 
antiblocking property or antioffset property, or deteriorate the toner's 
triboelectrification property to lower the durability. The toner of this 
invention, however, further comprises a copolymer as Constituent (C) 
comprised of two segment polymers which are compatible with both the 
polymer as Constitutent (A) and the polymer as Constituent (B), so that 
the respective segment polymers are partially dissolved into the polymer 
as Constituent (A) and the polymer as Constituent (B), respectively, and 
therefore the copolymer as Constituent (C) is coordinated at the boundary 
between the Constituent (A) polymer and the Constituent (B) polymer to 
play, so to speak, a surfactant-like role. Consequently, the Constituent 
(B) polymer comes to be microscopically uniformly dispersed and mixed into 
the Constituent (A) polymer. 
As a result, a toner having adequate fixability at a low temperature and 
antioffset property and excellent in the triboelectrification property as 
well as in the antiblocking property can be obtained, whereby a fogless, 
clear image can be stable formed. Also, displaying such excellent 
properties stably, the toner can form stably repeatedly excellent copies 
of an image. And, being satisfactory in the mixed condition of the 
respective polymers as well as in the dispersibility of a coloring agent 
thereinto, the toner can form an excellent color tone-having image. 
The present invention will be illustrated in detail. 
The above Constituent (A) is a non linear polymer. The linear polymer is 
desirable to be one that is capable of strongly retaining the low-melting 
polymer as Constituent (B) in the toner and of providing the toner with a 
high mold releasability. From this point of view, the linear polymer had 
better have a glass transition point Tg of preferably from 40.degree. to 
80.degree. C., more preferably from 50.degree. to 80.degree. C., and most 
preferably from 55.degree. to 70.degree. C. If the glass transition point 
Tg is extremely low, the antiblocking property can be lowered, while if it 
is extremely high, the fixability at a low temperature can be lowered. 
The glass transition point Tg herein, when measurement is carried out at a 
temperature-increasing speed of 10.degree. C./min by using a differential 
scanning calorimeter `Low-Temperature DSC` (manufactured by Rigaku Denki 
K.K.), is a temperature at an intersecting point of the extension of the 
base line below the glass transition point and the tangential line 
indicating the maximum inclination of the curve formed from the start of 
the peak up to the top of the peak. 
The nonlinear polymer is desirable to be of a weight average molecular 
weight Mw of not less than 50,000. If the weight average molecular weight 
Mw is extremely small, the antioffset property can be lowered. 
The nonlinear polymer content of the toner is preferably from 50 to 99% by 
weight, and more preferably from 55 to 95% by weight. When the content is 
extremely small, the antioffset property can be lowered, while then the 
content is extremely large, the fixability at a low temperature can be 
lowered. 
As for such the nonlinear polymer, and amorphous polymer may be suitable 
used. Usable examples of the amorphous polymer include those formed by 
nonlinearizing vinyl-type polymers, polyesters, epoxy resins, polyamides, 
polyurethanes, phenol resins, and the like, by using a cross-linking 
agent. Of these polymers, the nonlinearized vinyl-type polymers and the 
nonlinearized polyesters are particularly suitable. 
The nonlinear vinyl polymer can be obtained by the polymerization reaction 
of a vinyl group-having monomer with a polymerizable bifunctional or 
polyfunctional vinyl group having monomer for nonlinearization. Examples 
of the vinyl group-having monomer include sytrenes such as, e.g., styrene, 
o-methylstyrene, p-methylstyrene, p-ethylstyrene, .alpha.-methylstyrene, 
2,4-dimethylstyrene, p-tert-butylstyrene, p-n-octylstyrene, 
p-n-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 
3,4-dichlorostyrene, etc., and derivatives of these styrenes; vinyl esters 
such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, 
etc.; vinyl chloride; .alpha.-methylene aliphatic monocarboxylic acid 
esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl 
acrylate, tert-butyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl 
acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, 
phenyl acrylate, methyl .alpha.-chloroacrylate, dimethylaminoethyl 
acrylate, diethylaminoethyl acrylate, methyl methacrylate, ethyl 
methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl 
methacrylate, tert-butyl methacrylate, n-octyl methacrylate, dodecyl 
methacylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl 
methacrylate, etc.; acrylic acids or methacrylic acid derivatives such as 
acrylonitrile, methacrylonitrile, acrylamide, etc.; vinyl ethers such as 
vinyl-methyl ether, vinyl-ethyl ether, vinyl-isobutyl ether, etc.; vinyl 
ketones such as vinyl-methyl ketone, vinyl-hexyl ketone, vinyl-isopropenyl 
ketone, etc.; N-vinyl compounds such as N-vinylpyrrole, N-vinylcarbazole, 
N-vinylindole, N-vinylpyrolidone, etc.; vinylnaphthalenes; and the like. 
And examples of the above monomer having a bifunctional or polyfunctional 
vinyl polymer for nonlinearization include aromatic divinyl compounds such 
as, e.g., divinylbenzene, divinylhapthalene, and derivatives of these 
compounds, etc.; double bond-having carboxylic acid esters such as 
ethylene glycol diacrylate, ethylene glycol dimethacrylate, 
trimethylolpropane triacylate, etc.; and the like. 
Examples of the nonlinear amorphous vinyl-type polymer formed by the 
polymerization of the above monomers include styrene-n-butyl 
acrylate-divinylbenzene copolymer, styrene-n-butyl acrylate-methyl 
methacrylate-divinylbenzene copolymer, styrene-n-butyl acrylate-ethylene 
glycol dimethacrylate copolymer, and the like. 
The foregoing nonlinear polyester can be obtained by the condensation 
polymerization reaction of a dihydric carboxylic acid monomer and a 
dihydric alcohol monomer with a trihydric or polyhydric carboxylic acid 
monomer and/or a trihydric or polyhydric alcohol monmer for 
nonlinearization. 
Examples of the dihydric carboxylic acid monomer include aromatic 
carboxylic acids such as, e.g., terephthalic acid, isophthalic acid, 
naphthalenedicarboxylic acid, etc.; aromatic oxycarboxylic acids such as 
p-(2-hydroxyethoxy)-benzoic acid; aliphatic polycarboxylic acids such as 
succinic acid, fumaric acid, adipic acid, maleic acid, sebacic acid, 
decamethylenedicarboxylic acid, mesaconic acid, citraconic acid, itaconic 
acid, glutaconic acid, malonic acid, etc.; alicyclic polycarboxylic acids 
such as 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic 
acid, hexahydrophthalic acid, tetrahydrophthalic acid, etc.; acid 
anhydrides of these acids; dimers of lower alkyl esters with linolenic 
acid; and other dihydric organic acid monomers. 
Examples of the foregoing dihydric alcohol monomer include diols such as, 
e.g., ethylene glycol, diethylene glycol, triethylene glycol, 
1,2-propylene-glycol, 1,3-propylene-glycol, 1,4-butanediol, neopentyl 
glycol, 1,4-butenediol, etc.; 1,4-bis(hydroymethyl)-cyclohexane; 
etherified bisphenols such as bisphenol A, hydrogenated bisphenol A, 
polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A, etc.; and 
other dihydric alcohol monomers. 
Examples of the trihydric or polyhydric alcohol monomer for 
nonlinearization include, e.g., sorbitol, 1,2,3,6-hexanetetrol, 
1,4-sorbitane, pentaerythritol, dipentaerythritol, tripentaerythritol, 
sugar, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 
2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, 
trimethylolpropane, 1,3,5-trihydroxymethylbenzene, and the like. Examples 
of the trihydric or polyhydric carboxylic acid monomer include, e.g., 
1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 
1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 
1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 
1,2,5-hexanetricarboxylic acid, 
1,3-dicarboxyl-2-methyl-2-methylenecarboxylpropane, 
tetra(methylenecarboxy)methane, 1,2,7,8-octanetetracarboxylic acid, 
empol-trimeric acids, and acid anhydrides or lower alkyl esters of these 
acids. 
The above trihydric or polyhydric monomer is desirable to be used in a 
quantity ratio of from 0.1 to 80 mole % to the alcohol or acid constituent 
as the structural unit of the nonlinear polyester. 
The foreging Constituent (B) is incompatible with the foregoing Constituent 
(A) and is a low-melting polymer having a melting poing of from 50.degree. 
to 130.degree. C., and preferably from 50.degree. to 120.degree. C. If the 
low-melting polymer is compatible with Constituent (A), the toner's glass 
transition point is lowered, deteriorating the toner's antiblocking 
property. And if the melting point of the low-melting polymer is extremely 
low, the toner is deteriorated in the antiblocking property as well as in 
the antifilming property, while if the melting point is extremely high, 
the toner is deteriorated in the fixability at a low temperature. 
The melting point Tmp in this invention is defined as a value obtained by 
measuring in the following manner: The melting peak value obtained when 10 
mg of a sample is heated at a given temperature-increasing speed 
(10.degree. C./min.) according to the differential scanning calorimetry 
(DSC) by using, e.g., a `DSC-20` (Seiko Electronic Industry Co.) is 
defined as a melting point Tmp. 
The clause that `Component (B) is incompatible with Constituent (A)` herein 
implies that, when both polymers are meltenly mixed and then cooled to be 
solidified, the solid appears opaque, or that both polymers being in the 
moltenly mixed state show the respective constituent polymers' glass 
transition points. 
Such the low-melting polymer is desirable to have a number average 
molecular weight Mn of from 1,000 to 20,000 and a weight average molecular 
weight Mw of from 2,000 to 100,000. By using such the suitable molecular 
weight range-having low-melting polymer, an even more excellent antioffset 
property-having toner can be obtained, and, in the manufacturing process 
of the toner, the pulverizability of the toner is improved, whereby the 
toner's productivity can be raised. 
Values of the foregoing weight average molecular weight Mw and number 
average molecular weight Mn can be found by various methods. The values, 
although they differ slightly according to the method used, are to be 
defined in this invention as ones that are obtained in the following 
measuring method: 
According to the gel permeation chromatography (GPC), the weight average 
molecular weight Mw and number average molecular weight Mn are measured 
under the following condition: A solvent (tetrahydrofuran) is flowed at a 
flow rate of 1.2 ml per minute at 40.degree. C., and 3 mg of a 
tetrahydrofuran solution of a sample in a concentration of 0.2 g/20 ml, as 
the weight of the sample, are poured into the column, and a measurement is 
carried out. In measuring the molecular weight of a sample, a measuring 
condition is selected so that the molecular weight of the sample falls 
under the range where the logarithm and count number of the molecular 
weight of a calibration curve prepared from several monodisperse 
polystyrene reference samples form a straight line. 
The reliability of the measured results can be confirmed by the fact that 
the NBS 706 polystyrene reference sample, when measured under the above 
measuring condition, shows a weight average molecular weight Mw of 
28.8.times.10.sup.4 and a number average molecular weight Mn or 
13.7.times.10.sup.4. 
The column to be used in GPC may be any column as long as it satisfies the 
foregoing condition. To be concrete, for example, TSK-GEL, GMH 
(manufactured by Toyo Soda Mfg. Co.), etc. may be used. 
The solvent and measuring temperature are not restricted by the described 
conditions, and may be changed otherwise properly. 
The low-melting polymer content of the toner is preferably from 1 to 50% by 
weight, and particularly preferably from 5 to 40% by weight. By using such 
the suitable content range-having low-melting polymer, an even more 
excellent characteristic can be obtained in the toner. On the other hand, 
if the low-melting polymer content of the toner is extremely small, the 
toner's fixability at a low temperature can be deteriorated, whereas if it 
is extremely large, the toner's triboelectrification property, antioffset 
property and durability can be deteriorated. 
As such the low-melting polymer, crystalline polymers can be used. The 
crystalline polymer is a polymer at least part of which has a crystalline 
structure, and includes those homopolymers or copolymers whose at least 
one constituent is crystallilne, i.e., partially crystallized, showing a 
sharply clear melting point, and which, when in the solid state at a 
temperature lower than the melting point, show white turbidity in the 
crystallline portion thereof. 
Example of the crystalline polymer include 
at-least-partially-crystalline-structure-having crystalline polyesters, 
crystalline polyethers, crystalline polyamides, crystalline polyurethanes, 
crystalline polyacrylates, crystalline polymethacrylates, crystalline 
polyaldehydes, crystalline polyacids, crystalline polylactones, 
crystalline polyoxazoles, crystalline polyepihalohydrins, crystalline 
polysulfones, and the like. Of these, the crystalline polyesters are 
particularly preferred. 
Examples of the crystalline polyester include, e.g., polyethylene sebacate, 
polyethylene adipate, polyethylene suberate, polyethylene succinate, 
polyethylene-p-(carbophenoxy) undecaate, polyethylene-p-(carbophenoxy) 
butyrate, polyethylene-p-phenylene diacetate, polyhexamethylene carbonate, 
polyhexamethylene-p-(carbophenoxy) undecaate, polyhexamethylene oxalate, 
polyhexamethylene sebacate, polyhexamethylene decanedioate, 
polyoctamethylene dodecanedioate, polynonamethylene azelate, 
polynonamethylene terephthalate, polydecamethylene adipate, 
polydecamethylene azerate, plydecamethylene oxalate, polydecamethylene 
sebacate, polydecamethylene succinate, polydecamethylene dodecanedioate, 
polydecamethylene octadecanedioate, polytetramethylene sebacate, 
polytetramethylene-p-phenylene diacetate, polytrimethylene dodecanedioate, 
polytrimethylene octadecanedioate, polytrimethylene oxalate, poly-p-xylene 
adipate, poly-p-xylene sebacate, poly-4,4'-isopropylidenediphenylene 
adipate, poly-4,4'-isopropylidenephenylene malonate, 
polyhexamethylenedecamethylene sebacate, polydecamethylene 
sebacate-terephthalate, polydecamethylene-2-methyl-1,3-propanediol 
dodecanedioate, and other equivalents. 
The above crystalline polyester can be obtained by the condensation 
polymerization reaction of an alcohol monomer with a carboxylic acid 
monomer. Examples of the alcohol monomer include, e.g., ethylene glycol, 
diethylene glycol, 1,3-propylene-glycol, trimethylene glycol, 
tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, 
octamethylene glycol, nonamethylene glycol, decamethylene glycol, 
4,4'-isopropylidene-biphenol, p-xylene-glycol, neopentyl glycol, 
cyclohexanedimethanol, polyoxyethylenated bisphenol A, polyoxypropylenated 
bisphenol A, and the like. 
Examples of the carboxylic acid monomer include, e.g., malonic acid, 
succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, 
glutaconic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, 
decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic 
acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, 
isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, 
anhydrides of these acids, lower alkyl esters of these acids, and the 
like. 
The foregoing Constituent (C) is a copolymer formed by the chemical 
combination of a segment polymer which is at least compatible with the 
foregoing Constituent (A) and a segment polymer which is at least 
compatible with the foregoing Constituent (B). 
The term `compatible` herein implies that, when both polymers are moltenly 
mixed and then cooled to be in the solid state, the solid appears 
transparent, or that both polymers, in the moltenly mixed state, show a 
different glass transition point. 
The proportion of the copolymer as Constituent (C) to the toner is 
preferably from 1 to 50% by weight, and particularly preferably from 3 to 
40% by weight. If this proportion is extremely small, the dispersibility 
of a coloring agent as Constituent (D) can be deteriorated, while if it is 
extremely large, the durability of the toner can be deteriorated. 
The segment polymer which is compatible with Constituent (A) is desirable 
to be an amorphous segment polymer having a glass transition point Tg of 
from 50.degree. to 80.degree. C., and the segment polymer which is 
compatible with Constituent (B) is desirable to be a crystalline segment 
polymer having a melting point Tmp of from 50.degree. to 130.degree. C. 
The copolymer of these polymers is desirable to be a graft copolymer or a 
block copolymer. In the copolymer it is desirable that the segment polymer 
which is compatible with Constituent (A) and the segment polymer which is 
compatible with Constituent (B) be combined firmly by a covalent bond. 
The segment polymer which is compatible with Constituent (A) is desirable 
to be one selected from among these nonlinear polymers as Constituent (A), 
and particularly it is desirable that both be the same. And the segment 
polymer which is compatible with Constituent (B) is desirable to be one 
that is selected from among those low-melting polymers as Constituent (B), 
and particularly it is desirable that both be the same. 
As an example of concrete means to chemically combine the respective 
segment polymers for the formation of a copolymer as Constituent (C), the 
copolymer can be obtained by combining both the segment polymers by, e.g., 
the direct head-tail linkage of their terminal functional groups in the 
coupling reaction therebetween. 
In another example, the respective terminal functional groups of both 
polymers may be bound by the use of an at least bifunctional coupling 
agent. To be concrete, the copolymer can be obtained by such a linkage as, 
for example, the urethane linkage formed by the reaction between a polymer 
whose terminal group is a hydroxyl group and a diisocyanate; the linkage 
formed by the rection between a polymer whose terminal group is a hydroxyl 
group and a dicarboxylic acid; the ester linkage formed by the reaction 
between a polymer whose terminal group is a carboxyl group and a glycol; 
the linkage formed by the reaction between a polymer whose terminal group 
is a hydroxyl group and phosgene or dichlorodimethylsilane; or the like. 
Examples of such the coupling agent include isocyanates such as 
hexamethylene diisocyanate, diphenylmethane diisocyanate, tolylene 
diisocyanate, tolidine diisocyanate, napthylene diisocyanate, isophorone 
diisocyanate, xylilene diisocyanate, etc.; amines such as ethylenediamine, 
hexamethylenediamine, phenylenediamine, etc.; carboxylic acids such as 
oxalic acid, succinic acid, adipic acid, sebacic acid, terephthalic acid, 
isophthalic acid, etc.; alcohols such as ethylene glycol, propylene 
glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol, 
p-xylilene-glycol, etc.; acid chlorides such as terephthalic acid 
chloride, isophthalic acid chloride, adipic acid chloride, sebacic acid 
chloride, etc.; and other coupling agents such as diisothiocyanates, 
bisketenes, biscarbodiimides, and the like. 
The using proportion of these coupling agents is preferably from 1 to 10% 
by weight, and particularly preferably from 2 to 7% by weight to the total 
weight of the segment polymer. 
Other methods for obtaining the foregoing copolymer include, for example, 
the following methods: A segment polymer compatible with Constituent (A) 
is first sythesized in usual manner, and then to this is added a monomer 
necessary to form a segment polymer compatible with Constituent (B) to 
thereby combine both of them so as to have the segment polymer compatible 
with Constituent (B) extend from the terminal of the segment polymer 
compatible with Constituent (A), whereby a copolymer can be obtained. 
Alternatively, the copolymer may also be obtained in the manner that the 
segment polymer compatible with Constituent (B) is first synthesized in 
usual manner, and then to this is added a monomer necessary to form the 
segment polymer compatible with Constituent (A) to thereby combine both so 
as to have the segment polymer compatible with Constituent (A) extend from 
the terminal of the segment polymer compatible with Constituent (B). 
In the formation of the copolymer as Constituent (C), if necessary, an 
additional different segment polymer may also be used in addition to the 
segment polymer compatible with Constituent (A) and the segment polymer 
compatible with Constituent (B). 
The toner of this invention may also contain different other resins in 
addition to the above Constituents (A), (B) and (C). Examples of the 
additional different resin include, e.g., styrene-acryl-type copolymers, 
polyesters, polyamides, polyurethanes, epoxy resins, and the like. 
Examples of the coloring agent as Constituent (D) include, e.g., carbon 
black, Nigrosine dye (C.I. No50415B), Aniline Blue (C.I. No.50405), Calco 
Oil Blue (C.I. No. azoic Blue 3), Chrome Yellow (C.I. No.14090), 
Ultramarine Blue (C.I. No77103), DuPont Oil Red (C.I. No.26105), Quinoline 
Yellow (C.I. No.47005), Methylene Blue Chloride (C.I. No.52015), 
Phthalocyanine Blue (C.I. No.74160), Malachite Green Oxalate (C.I. 
No.42000), Lumpblack (C.I. No.77266), Rosebengal (C.I. No.45435), mixtures 
of these dyes or pigments, and others. 
In addition, various other organic or inorganic coloring dyes or coloring 
pigments may also be used. Particularly, organic coloring pigments vivid, 
clear in color, having a high resistance to light and a high crypticity, 
are suitable. To be concrete, for example, the following coloring agents 
may be used. The following exmplified materials each is indicated by the 
C.I. name and number described in the Color Index, 3rd ed., 1971 and its 
supplement 1975, along with an example of corresponding trade names: 
C.I. Pigment Red 5 
(Permanent Carmine FB, produced by Hoecht Japan) 
C.I. Pigment Red 48:1 
(Sumikaprint Red C, produced by Sumitomo Chemical Co.) 
C.I. Pigment Red 53:1 
(Chromophthal Magenta G, produced by Ciba Geigy) 
C.I. Pigment Red 57:1 
(Sumikaprint Carmine 6BC, produced by Sumitomo Chemical Co.) 
C.I. Pigment Red 123 
(Kayaset Red E-B, produced by Nippon Kayaku K.K.) 
C.I. Pigment Red 139 
(Kayaset Red E-GR, produced by Nippon Kayaku K.K.) 
C.I. Pigment Red 144 
(Chromophthal Red BRN, produced by Ciba Geigy) 
C.I. Pigment Red 149 
(PV Fast Red B, produced by Hoecht Japan) 
C.I. Pigment Red 166 
(Chromophthal Scarlet R, produced by Ciba Geigy) 
C.I. Pigment Red 177 
(Chromophthal Red A.sup.3 B, produced by Ciba Geigy) 
C.I. Pigment Red 178 
(Kayaset Red E-GG, produced by Nippon Kayaku K.K.) 
C.I. Pigment Red 222 
(Chromophthal Red Magenta G, produced by Ciba Geigy) 
C.I. Pigment Orange 31 
(Chromophthal Orange 4R, produced by Ciba Geigy) 
C.I. Pigment Orange 43 
(Hostaperm Orange GR, produced by Hoecht) 
C.I. Pigment Yellow 17 
(Fast Yellow GBFN, produced by Suimitomo Chemical Co.) 
C.I. Pigment Yellow 14 
(Benzidine Yellow OT, produced by DuPont) 
C.I. Pigment Yellow 138 
(Pariotol Yellow L0960HD, produced by BASF) 
C.I. Pigment Yellow 93 
(Chromophthal Yellow 3G, produced by Ciba Geigy) 
C.I. Pigment Yellow 94 
(Chromophthal Yellow 66, produced by Ciba Geigy) 
C.I. Pigment Green 7 
(Chromophthal Green GF, produced by Ciba Geigy) 
C.I. Pigment Green 36 
(Cyanine Green S537-2Y, produced by Dainichi Seika) 
C.I. Pigment Blue 15:3 
(Cyanine Blue A330, produced by Sanyo Shikiso) 
C.I. Pigment Blue 60 
(Chromophthal Blue A3R, produced by Ciba Geigy) 
C.I. Pigment Violet 23 
(Sumikaprint Fast Violet RLN, produced by Sumitomo 
Chemical Co.) 
If necessary, inorganic pigments such as red oxide, titanium oxide, carbon 
black, etc., may also be used along with the above materials. 
As the coloring dye, for example, azo dyes, anthraquinone dyes, indigo 
dyes, quinoneimine dyes, phthalocyanine dyes, etc. may be used. 
These coloring agents may be used either alone or in combination of two or 
more of them. The proportion of the coloring agent to the toner is 
desirable to be 1-20 parts by weight to 100 parts by weight of the toner. 
Where the toner is to be a magnetic toner, coloring capability-having 
magnetic materials can be used as the coloring agent. 
The essential constituents of the toner of this invention have been 
described above, but the toner of this invention may, if necessary, 
contain other additives. Such additives include, for example, magnetic 
materials, antioffset agents, fixability improving agents, fluidity 
improving agents, abrasives, charge control agents, and the like. These 
additives may be contained either in the mixedly dispersed state in the 
polymer or in the state of adhering to or eating into the polymer grains' 
surface. 
Examples of the foregoing magnetic material include ferrite, magnetite, 
ferromagnetic metals such as iron, cobalt, nickel, etc.; alloys of these 
metals; compounds containing these elememts; those alloys which do not 
contain any ferromagnetic elements but, when subjected to a proper heat 
treatment, show ferromagneticity; those manganese-and-copper-containing 
alloys called `whistler alloy` such as, for example, 
manganese-copper-aluminum, manganese-copper-tin, and the like; and 
chromium dioxide and others. Any of these magnetic materials is desirable 
to be in the fine powdery form having an average grains size of from 0.1 
to 1 .mu.m and to be contained in the uniformly dispersed state in the 
polymer. Where the toner is to be a magnetic toner, the proportion of the 
magnetic material to the toner is preferably from 20-70 parts by weight to 
100 parts by weight of the toner, and particularly preferably 25 to 50 
parts by weight. 
As the foregoing antioffset agent or fixability improving agent, for 
example, a wax having a melting point of from 50.degree. to 150.degree. 
C. may be suitably used. Examples of such the agent include liquid or 
solid paraffin, polyolefins such as polyethylene, polyrpopylene, etc., 
fatty acid metallic salts, fatty acid esters, partially saponified fatty 
acid esters, higher fatty acids, higher alcohols, silicone varnish, 
amide-type waxes, aliphatic fluorocarbons and their modified compounds, 
and the like. The proportion of the agent to the toner is preferably from 
0.1 to 30% by weight, and particularly preferably from 0.2 to 10% by 
weight. The use of such the antioffset or fixability improving agent as a 
constituent of the toner makes the toner's property even more excellent. 
For example, the heat roller fixing process usually uses a cleaning roller 
closely juxtaposed to the heat roller to thereby remove the toner stain 
from the surface of the heat roller, but where the toner contains the 
above antioffset or fixability improving agent, the toner material is 
effectively prevented from being transferred to adhere onto the heat 
roller, so thaat the use of the agent is advantageous in respect of 
lengthening the usable life span of both cleaning and heat rollers. 
As the foregoing fluidity improving agent or abrasive, for example, 
inorganic fine particulate materials or other equivalents may be used, and 
their primary particle size is preferably from 5 m.mu. to 2 m.mu., and 
more preferably from 5 m.mu. to 500 m.mu.. And their specific surface area 
according to the BET method is desirable to be from 20 to 500 m.sup.2 /g. 
The proportion of such the fine particulate material to the toner is 
preferably from 0.01 to 5% by weight, and particularly preferably from 0.1 
to 2.0% weight. These fine particles are desirable to be contained in the 
toner in the state of adhering to or eating into the toner grains' 
surface. Useful examples of the fine particulate material include silica, 
alumina, titanium oxide, barium titanate, magnesium titanate, calcium 
titanate, strontium titanate, zinc oxide, silica sant, clay, mica, 
wollastonite, diatom earth, chromium oxide, cerium oxide, red oxide, 
antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, 
barium carbonate, calcium carbonate, silicon carbide, silicon nitride, and 
the like. Out of these materials, the silic fine particulate material is 
particularly useful. 
The silica fine particulate material is one having the following structural 
formula, which may be one prepared by either the wet process or the dry 
process. 
##STR1## 
The silica may be in the form of any of anhydrous silica dioxide, aluminum 
silicate, sodium silicate, potassium silicate, magnesium silicate, zinc 
silicate, or the like, and is particularly preferably one containing more 
than 85% by weight SiO.sub.2. 
There are a variety of commercially available silica products, but among 
them those having a hydrophobic group on the surface thereof are suitable 
usable. Such useful products are, for example, `Aerosil R-972,` `Aerosil 
R-974,` `Aerosil R-805,` `Aerosil R-812,` (produced by Nippon Aerosil), 
and `Talanox 500` (produced by Talco), and the like. Besides, those silica 
fine particles surface-treated by a silane-coupling agent, 
titanium-coupling agent, silicone oil, or a silicone oil having amine on 
its side chain, or the like, may be effectively used. 
As the foregoing charge control agent any known materials may be used 
without being particularly restricted. Negatively chargeable ones of these 
materials includes those 2:1-type metal-containing azo dyes as disclosed 
in, e.g., Japanese Patent Publication Open to Public Inspection 
(hereinafter referred to as Japanese Patent O.P.I. Publication) Nos. 
141452/1982, 7645/83, 111049/1983, 185653/1983, 167033/1982, 6397/1969, 
etc.; those metallic complex salts of aromatic oxycarboxylic acids and 
aromatic dicarboxylic acids as disclosed in Japanese Patent O.P.I. 
Publication Nos. 104940/1982, 111541/1982, 124357/1982, 127726/1983, etc.; 
those sulfonylamine derivatives of copper-phthalocyanine dyes or 
sulfonamido derivative dyes of copper-phthalocyanines, and sulfonamides, 
sulfonic acid or sulfonic acid salt derivative dyes of 
copper-phthalocyanines as disclosed in Japanese Patent O.P.I. Publication 
No. 45931/1977; and the like. 
Positively chargeable ones of these materials as the charge control agent 
include those quaternary ammonium compounds as disclosed in Japanese 
Patent O.P.I. Publication Nos. 51951/1974, 10141/1977, etc.; those 
alkylpyridinium compounds as disclosed in Japanese Patent O.P.I. 
Publication Nos. 11461/1981 and 158932/1979, and U.S Pat. No. 4,254,205; 
nigrosine-type dyes such as Nigrosine SO, Nigrosine EX, etc.; those 
addition condensates as disclosed in Japanese Patent Examined Publication 
No. 80320/1974; and the like. 
The proportion of such the charge control agent to the toner is preferably 
from 0.1 to 10% by weight, and particularly preferably from 0.3 to 5% by 
weight. 
The softening point Tsp of the toner of this invention is preferably from 
90.degree. to 150.degree. C., and particularly preferably from 100.degree. 
to 140.degree. C. If the softening point Tsp is extremely low, the 
antioffset property of the toner can be deteriorated, while if it is 
extremely high, the fixability at a low temperature can be deteriorated. 
The terms `softening point Tsp` herein means a temperature at the time of 
h/2, the h being the height of the S-shaped curve, the plunger's descent 
amount-temperature curve (softening-fluidity curve), obtained when 1.0 
cm.sup.3 quantity of a sample (a weight expressed by absolute specific 
gravity.times.1 cm.sup.3) is measured and recorded by use of a flow 
tester CFT-500 (manufactured by Shimazu Seisakusho, Ltd.) under the 
conditions of a load of 20 kg/cm.sup.2, a nozzle diameter of 1 mm, 
preheating at 50.degree. C. for 10 minutes, and a temperature increasing 
rate of 6.degree. C./min. 
The toner of this invention may be produced by, e.g, the following method: 
To a specific polymer constituent as mentioned previously or to one formed 
by adding other resins thereto are added a coloring agent and, if 
necessary, further other additives, and these are then molten and kneaded 
by, e.g., an extruder. The kneaded product is cooled and then pulverized 
by means of a jet mill or the like and then classified, whereby a desired 
grain size-having powdery toner can be obtained. Further, if other 
odditives are additionally added and mixed into the toner, a toner 
improved on its characteristics may be obtained. 
Alternatively, if the toner moltenly kneaded by an extruder, with the 
molten state being kept intact, is sprayed by a spray dryer or dispersed 
into a liquid, any desired grain size-having toner can be obtained. 
The toner of this invention is for use in heat-roller fixing, and the image 
formation with this toner is carried out in, e.g., the following manner: 
That is, in the electrophotographic process, and electrostatic latent 
image formed on a latent image carrer photoreceptor is developed by a 
developer comprising the toner of this invention, and the obtained toner 
image is then transferred, e.g., electrostatically, onto a copying sheet 
made of paper or the like. The transferred toner image is then fixed by 
the heat-roller fixing process, whereby a visible image is formed. The 
heat-roller fixing device to be used in the heat-roller fixing process is 
comprised generally of a heat roller, a contact roller which is closely 
juxtaposed to the heat roller, and a heat source. And the fixing device, 
with the heat roller being heated by the heat souce so as to be kept in a 
specified temperature range, allows a support bearing the transferred 
toner image to pass between the pair of rollers to come into direct 
contact with the heat roller, whereby the toner image is thermally fixed 
to the support. 
The toner of this invention displays a remarkably excellent effect compared 
to conventional toners particularly in the case where a fixing operation 
is made at such a high speed that the time of contact of the toner image 
on a support with the heat roller is within 1 second, preferably not more 
than 0.5 second.

Examples 
Examples of the present invention and compartive examples will be 
illustrated in detail below, but the invention is not limited to and by 
the following examples. 
The respective compositions of the polymers used in the following examples 
of this invention and comparative examples are as given in Table 1, Table 
2 and Table 3 which will be hereinafter set forth. And in the examples and 
comparative examples, the respective polymers were used in the 
combinations and proportions given in Table 4. 
EXAMPLES 1 TO 6 AND COMATIVE EXAMPLES 1 TO 5 
In the examples and comparative examples, the respective toners therefor 
were prepared in the following manner: 
One hundred parts by weight of each total amount of the polymers given for 
each sample in Table 4, each coloring agent, 3 parts by weight of 
polypropylene `Viscol 660P` (produced by Sanyo Chemical Ind. Co.), 2 parts 
by weight of `Wax-E` (produced by Hoecht) and 2 parts by weight of a 
charge control agent `Bontron E-81` (produced by Orient Chemical Co.) were 
mixed and kneaded by means of a heat roll, then cooled and then 
pulverized, and further finely pulverized by an ultrasonic jet mill, and 
subsequently classified by a wind classifier, whereby a colored 
particulate material was obtained. 
To 100 parts by weight of the obtained colored particulate material was 
added 0.8 part by weight of a hydrophobic silica powder `Aerosil R-972` 
(produced by Nippon Aerosil), and these were mixed by a V-type mixer, and 
thus, in this manner, toners having a volume average size of 11.0 .mu.m 
were obtained. 
These toners obtained in Examples 1 to 6 and Comparative Examples 1 to 5 
were regarded as Toner-1 through Toner-6 and Compatative Toner-1 through 
Comparative Toner-5, respectively. 
Subsequently, 3 parts by weight of each of Toners-1 to -6 and Comparative 
Toners-1 to -5 were mixed with 97 parts by weight of a styrene-methyl 
methacrylate copolymer resin-coated carrier having an average grain size 
of 110 .mu.m, whereby 11 different developers were prepared. These 
developers each was used to perform a practical copying test in an 
electrophotographic copying apparatus `U-Bix 5000` (manufactured by 
Konishiroku Photo Industry Co.) to form an electrostatic latent image and 
then develope the image, and the thus obtained toner image was transferred 
onto a copying sheet of paper, and the transferred toner image was then 
fixed by the heat-roller fixing device to thereby obtain a copy image, and 
in the test, the minimum fixing temperature (fixable minimum temperature 
of the heat roller) and offset occurring temperature (offset phenomenon 
occurring minimum temperature) were measured, and at the same time the 
fixable temperature range was found. 
MINIMUM FIXING TEMPERATURE 
In the above-mentioned copying apparatus, an unfixed toner image by the 
sample toner was formed and then transferred onto a 64 g/m.sup.2 copying 
paper, and the formed toner image was fixed by a heat-roller fixing device 
comprised of a 50.phi. heat roller whose surface layer is formed with a 
Teflon coat (polytetrafluoroethylene, produced by DuPont) and a pressure 
roller whose surface layer is formed with a silicone rubber `KE-1300RTV` 
(produced by Shin'etsu Chemical Industry Co.) under the conditions of a 
heat roller's linear speed of 200 mm/sec., a linear pressure of 0.8 kg/cm, 
and a nip width of 8.0 mm; this fixing procedure was repeated at each 
staged temperature increase by 5.degree. C. within the range of from 
80.degree. to 230.degree. C., and these formed fixed images each was then 
subjected to a rubbing test using the same paper as that of the copy image 
by means of a fastness tester, and the minimum of temperatures set for the 
fixed image showing its adequate resistance to rubbing was regarded as the 
minimum fixing temperature. The heat-roller fixing device used herein is 
one having no silicone oil supply mechanism. 
OFFSET OCCURRING TEMPERATURE 
Measurement of the offset occurring temperature is similar to that of the 
above minimum fixing temperature: After the formation of an unfixed image 
in the foregoing copying apparatus, the toner image was transferred onto a 
copying paper and then fixed by the above heat roller fixing device. After 
that, a plain white paper sheet, under the same condition, was sent 
through the heat-roller fixing device to observe whether the paper is 
stained or not by the toner. This precedure was repeated, gradually 
increasing the temperature of the heat roller of the heat-roller fixing 
device, and the minimum of temperatures set when the toner stain appeared 
was regarded as the offset occurring temperature. 
FIXABLE TEMPERATURE RANGE 
The difference between the offset occurring temperature and the minimum 
fixing temperature measured in the above manner was regarded as the 
fixable temperature range. 
The results obtained in above are shown in Table 5. 
Further, the antiblocking property, color tone, and quqntity of charge 
(Q/M) of the toner were measured as follows: 
ANTIBLOCKING PROPERTY 
Each toner was allowed to stand for two hours under the environmental 
condition of a temperature of 50.degree. C. with a relative humidity of 
43% to judge whether agglomerated lumps are produced or not in the toner, 
and the toner, where no such lumps were found, is indicated with `O`, 
where such lumps were found to some extent, is indicated with `.DELTA.`, 
and, where such lumps were found remarkably, is indicated with `X` in 
Table 5. 
COLOR TONE 
It was judged by the eye. 
QUANTITY OF CHARGE (Q/M) 
This was measured by the blow-off method of the prior art, and the quantity 
of the triboelectrified charge per gram of the toner was regarded as the 
quantity of charge (Q/M). 
The results obtained in above are also given in Table 5. 
In addition, the image copies obtained in the practical copying tests with 
use of the foregoing copying apparatus were evaluated with respect to 
fogging and clearness as follows: 
FOG 
A SAKURA Densitometer (manufactured by Konishiroku Photo Industry Co.) was 
used to measure and evaluate the relative density of each developed image 
corresponding to the original's white background density being 0.0, 
provided the reflection density of the white background was regarded as 
0.0. The results of the evaluation are given in Table 5 by indicating a 
mark of `O` for one having a relative density of less than 0.01, a mark of 
`.DELTA.` for one having a relative density of not less than 0.01 and less 
than 0.03, and a mark of `X` for one having a relative density of not less 
than 0.03. 
CLEARNESS 
A line drawing chart was used as an original, and the reproducibility of 
each formed image from the original was enlarged to be judged visually. 
The results of the evaluation in the judgement are given in Table 5 by 
indicating a mark of `O` for one showing good reproduction, a mark of 
`.DELTA.` for one considered not good but practically usable, and a mark 
of `X` for one so poor in the reproduction that it is unacceptable for 
practical use. 
All the above results are as given in Table 5. 
Further, practical copying tests were repeated in succession in the 
foregoing copying apparatus to thereby examine the durability of each 
toner as follows: 
The image forming process was repeated 30,000 times in the copying 
apparatus, and the 30,000th copy image was measured and evaluated with 
respect to its fog and clearness in similar manner to the above. The 
obtained results are also given in Table 5. 
TABLE 1 
______________________________________ 
Glass tran- 
Soften- 
sition point 
ing point 
Polymer A (for the invention) 
Tg (.degree.C.) 
Tsp (.degree.C.) 
______________________________________ 
A-1 Styrene/n-butyl-acrylate/divinyl- 
66 134 
benzene copolymer 
(proportion by wt = 83.5:15:1.5) 
A-2 Styrene/methyl methacrylate/n- 
58 126 
butylacrylate/divinylbenzene 
copolymer 
(proportion by wt = 68:10:20:2) 
A-3 Polyoxypropylenebisphenol 
65 128 
A/terephthalic 
acid/trimellitic acid condensation 
polymerization product 
(molar ratio = 50:20:30) 
______________________________________ 
TABLE 2 
__________________________________________________________________________ 
Melting 
Wt average 
Number average 
point molecular wt 
molecular wt 
Polymer B Tmp (.degree.C.) 
Mw Mn 
__________________________________________________________________________ 
For B-1 
Polyhexamethylene 
65 14,000 4,600 
inven- sebacate 
tion 
B-2 
Polydecamethylene 
78 12,000 3,800 
adipate 
B-3 
polyethylene succinate 
95 8,900 3,100 
B-4 
Polyethylene sebacate 
72 10,400 3,300 
B-5 
Polytrimethylene sebacate 
53 6,300 2,000 
B-6 
Polydecamethylene 
129 8,700 2,400 
terephthalate 
Com- 
B-7 
Polyethylene adipate 
47 7,600 2,900 
para- 
B-8 
Polyhexamethylene 
160 9,100 3,200 
tive terephthalate 
__________________________________________________________________________ 
TABLE 3 
__________________________________________________________________________ 
Polymer a compati- 
Polymer b compati- 
Coupling agent for chemical combination of 
ble with Polymer A 
ble with Polymer B 
Polymer a with Polymer b 
Copoly- Proportion 
Proportion Proportion 
mer Type 
(parts by wt) 
Type 
(parts by wt) 
Type (parts by wt) 
__________________________________________________________________________ 
C-1 a-1 
80 B-1 
20 Hexamethylene diisocyanate 
4 
C-2 a-2 
70 B-3 
30 Toluylene diisocyanate 
4 
C-3 a-2 
75 B-2 
25 Hexamethylene diisocyanate 
4 
C-4 a-1 
75 B-4 
25 Toluylene diisocyanate 
4 
C-5 a-1 
80 B-5 
20 Hexamethylene diisocyanate 
4 
C-6 a-1 
80 B-6 
20 Hexamethylene diisocyanate 
4 
C-7 a-1 
80 B-7 
20 Hexamethylene diisocyanate 
4 
C-8 a-1 
80 B-8 
20 Hexamethylene diisocyanate 
4 
__________________________________________________________________________ 
Note: 
a1: Polypropylene isophthalate (glass transition point Tg = 54.5.degree. 
C., weight average molecular weight Mw = 13,400, Number average molecular 
weight Mn = 4,500) 
a2: Polyoxypropylenebisphenol A/fumarate/terephthalate (molar ratio = 
2:1:1) (glass transition point Tg = 67.degree. C., weight average 
molecular weight Mw = 13,300, number average molecular weight Mn = 4,600) 
B1 through B8 are the same as the Polymers B in Table 2. 
TABLE 4 
__________________________________________________________________________ 
Polymer A 
Polymer B 
Polymer C 
Coloring agent 
Type 
Ratio 
Type 
Ratio 
Type 
Ratio 
Type Ratio 
__________________________________________________________________________ 
Toner 1 A-1 
70 B-1 
20 C-1 
10 Carbon black `Mogal L` (Cabot) 
10 
Toner 2 A-2 
65 B-2 
25 C-3 
10 `PV Fast Red B` (Hoecht 
6pan) 
Toner 3 A-3 
65 B-3 
25 C-2 
10 `Benzidine Yellow OT` (DuPont) 
4 
Toner 4 A-1 
70 B-4 
25 C-4 
5 `Cyanine Blue A 330` (Sanyo 
5ikiso) 
Toner 5 A-3 
75 B-5 
15 C-5 
10 Carbon black `Mogal L` (Cabot) 
10 
Toner 6 A-3 
55 B-6 
35 C-6 
10 Carbon black `Mogal L` (Cabot) 
10 
Comparative Toner 1 
A-3 
65 B-7 
25 C-7 
10 Carbon black `Mogal L` (Cabot) 
10 
Comparative Toner 2 
A-3 
65 B-8 
25 C-8 
10 Carbon black `Mogal L` (Cabot) 
10 
Comparative Toner 3 
A-3 
75 B-3 
25 -- -- Carbon black `Mogal L` (Cabot) 
10 
Comparative Toner 4 
-- -- B-1 
100 -- -- Carbon black `Mogal L` (Cabot) 
10 
Comparative Toner 5 
A-1 
100 -- -- -- -- Carbon black `Mogal L` (Cabot) 
10 
__________________________________________________________________________ 
Note: 
The values shown in the `Ratio` columns are in parts by weight. 
TABLE 5 
__________________________________________________________________________ 
Minimum 
Offset 
Fixable Q'ty 30,000th 
fixing 
occurring 
temp. Anti- of copy image 
temp. 
temp. range blocking 
Color 
charge Clear- Clear- 
Toner (.degree.C.) 
(.degree.C.) 
(.degree.C.) 
property 
tone 
.mu.C/g 
Fog 
ness 
Fog 
ness 
__________________________________________________________________________ 
Toner 1 95 above 230 
above 135 
O Good 
-21 O O O .DELTA. 
Toner 2 105 above 230 
above 125 
O Good 
-23 O O O O 
Toner 3 100 above 230 
above 130 
O Good 
-22 O O O O 
Toner 4 95 above 230 
above 135 
O Good 
-21 O O O O 
Toner 5 95 230 135 O Good 
-19 O O O .DELTA. 
Toner 6 105 above 230 
above 125 
O Good 
-23 O O O O 
Comparative Toner 1 
100 135 85 X Good 
-10 X X X X 
Comparative Toner 2 
160 above 230 
above 70 
O Good 
-21 O O O O 
Comparative Toner 3 
110 above 230 
above 120 
O Bad -12 .DELTA. 
.DELTA. 
X X 
Comparative Toner 4 
90 90 None O Bad -5 X X X X 
Comparative Toner 5 
160 above 230 
above 70 
O Good 
-23 O O O O 
__________________________________________________________________________ 
As is understood from the results given in Table 5, any of Toners 1 to 6 is 
excellent in the fixability at a low temperature, antioffset property, 
antiblocking property, triboelectrification property, durability and color 
tone, and is capable of stably forming a clear image with no fog. 
In contrast, Comparative Toner 1, since the melting point of its 
low-melting polymer as Constituent (B) is extremely low, is so poor in the 
antiblocking property that the resulting copy image is unclear with much 
fog, and these shortcomings become more conspicuous after making 30,000 
image copies, so that the toner is eventually inferior in the durability. 
Comparative Toner 2, since the melting point of its low-melting polymer is 
extremely high to the contrary, is so poor in the fixability at a low 
temperature that it tends to cause an inadequate-fixation trouble. 
Comparative Toner 3, since it contains no copolymer as Constituent (C), 
shows inadequate dispersion of the coloring agent, so that the obtained 
copy image is poor in the color tone, and the toner's triboelectrification 
property is low, resulting in the copy image being unclear with much fog. 
These shortcomings become more conspicuous after making 30,000 image 
copies, so that the toner is eventually inferior in the durability. 
Comparative Toner 4, since it contains neither any linear polymer as 
Constituent (A) nor any copolymer As Constituent (C), is poor in the 
antioffset property and triboelectrification property as well as in the 
coloring agent's dispersibility, thus resulting in the copy image being 
nuclear image with much fog. 
And Comparative Toner 5, since it contains neither any low-melting polymer 
as Constituent (C) nor any copolymer as Constituent (C), is so poor in the 
fixability at a low temperature that it tends to cause an 
inadequate-fixation trouble.