JPS6329257B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developer for developing an electrostatic latent image formed on, for example, a photoconductor, an insulator, etc., and particularly relates to an improvement in a developer using a carrier liquid.

The liquid development method, which uses a liquid as a carrier, can reduce the particle size of the toner compared to so-called dry development methods, so it has excellent image gradation, reproducibility, and resolution, and can produce extremely excellent image reproduction. In addition, the developing device and the fixing device can be treated as liquids themselves, or can be made to have so-called self-fixing properties by evaporating the liquid, so they can be made extremely simple, low-cost, and compact. It is also possible to clean the photoreceptor for reuse or to transfer it to other recording materials for permanent preservation, and application to so-called PPC copying machines using the transfer method is also extremely useful. It is a method.

The developer of this type is one in which a coating material such as a colorant or a resin is dispersed in a carrier liquid which is a dispersant. Generally, products made in this form do not have sufficient charging characteristics or stability, so it is necessary to add surfactants such as metal soaps or add special functional groups to the coating material. Its characteristics have been improved through the introduction of

However, conventional liquid developers still have insufficient charging characteristics, and a sufficient density cannot be obtained unless the latent image is formed at a high potential, and they are also insufficiently stable, resulting in complete deterioration after long-term storage of six months or several years. The dispersibility was insufficient, resulting in uneven images, or the images changed during continuous use. Equipment that uses conventional developer using the earlier transfer method, so-called
When used in PPC equipment, etc., the transfer characteristics may change after long-term use. Furthermore, the biggest drawback of conventional developers is that when used continuously, for example, even if clear images can be obtained for several hundred to several thousand sheets, if used continuously beyond that, the images become faint or blurred. This means that the developer becomes unusable and the developer must be replaced. In this respect, it was fundamentally inferior to dry development.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid developer that has excellent image reproducibility, and in particular can provide a clear image even with a low voltage electrostatic latent image. A second object is to provide a liquid developer with particularly excellent dispersibility.

A third object is to provide a liquid developer with excellent storage stability.

A fourth object is to provide a liquid developer with excellent durability.

A fifth object is to provide a liquid developer that is not affected by environmental changes such as temperature. Its feature lies in an electrostatic latent image developer containing a carrier liquid, a colorant, a binder resin insoluble in the carrier liquid, and polyaminopolybutenyl succinimide.

Polyamide polybutenyl succinimide is synthesized by maleating polybutene with a molecular weight of around 1000 to form polybutenyl succinic anhydride, and reacting this with a polyamine. It is used as an ashless detergent and dispersant in engine oil additives, for example. It has a structure like this.

Conventionally, it has been synthesized from transition metals such as calcium, barium, manganese, cobalt, nickel, copper, zinc, lead, and zircon with naphthenic acid, octenoic acid, and stemaric acid for the purpose of charge control to improve the dispersibility of developers. So-called metal soaps, organophosphorus compounds such as triphenyl phosphite and triotadecyl phosphite, organotin compounds such as butyltin malate and dibutyltin oxide, epoxy compounds, organic acid esters or anions of polyhydric alcohols, or It is known and has been put into practical use to add small amounts of cationic and nonionic surfactants. However, all of the conventionally known additives have insufficient charge control, insufficient dispersion, and even if they are sufficiently effective when preparing developers, they cannot be stored for long periods of time. The effect has disappeared. Furthermore, especially when the developer is used repeatedly,
When any of the additives was used, the performance of the developer deteriorated, resulting in a decrease in image density, deterioration in image quality, poor cleaning, etc., and the developer had to be replaced. Conventionally, this phenomenon of developer deterioration has been considered to be a fateful phenomenon of liquid developers, and it has been thought that it would be impossible to obtain a developer with long-term durability and a liquid developer that does not need to be replaced. Ta.

The present inventor has conducted intensive research to improve these conventional drawbacks, and by using polyaminopolybutenyl succinimide, the conventional drawbacks were completely resolved without using conventional additives. We succeeded in obtaining a liquid developer that A liquid developer using polyaminopolybutenyl succinimide has excellent charging characteristics and excellent image reproducibility, and is a liquid developer that can provide a clear image even with a low potential electrostatic latent image. It also has excellent dispersion stability, its properties do not change even after long-term storage, and it is an extremely stable developer against environmental changes such as temperature. Furthermore, liquid developers using polyaminopolybutenyl succinimide have particularly excellent durability. That is, even if the same developer is used many times, the characteristics of the developer do not change, and it is possible to construct a developer that has the same developing characteristics as the initial one.

Although the cause of this effect of polyaminopolybutenyl succinimide has not been completely elucidated, it is believed to be due to the following reasons based on experimental facts.

A substance that provides charge control and a stable dispersion function must at least have excellent affinity with the carrier liquid, and must have excellent adsorption ability for toner particles and the ability to impart a charge while being adsorbed. , polyaminopolybutenyl succinimide is superior to conventional additives in both of these areas. This is thought to have a polybutenyl group, which is a much larger lipophilic group than the stearyl group of conventional metal soaps, and can be dispersed and dissolved in the carrier liquid in a favorable manner. In fact, polyaminopolybutenyl succinimide is extremely easily dispersed in conventionally known carrier liquids such as n-paraffin, isoparaffin, and chlorinated paraffin, and does not precipitate even after long periods of standing, cooling, etc. There is no change at all. Furthermore, polyaminopolybutenyl succinimide has a large adsorption ability for toner particles. For example, after polybutenyl succinimide is added to the toner dispersion, the carrier component is removed by centrifugal filtration, etc., and the carrier liquid is further removed. This is clear from the fact that it is still controlled even when it is redispersed. Such adsorption ability is presumed to be due to the fact that polyaminopolybutenyl succinimide has a strong polar group called an amino group.

Materials in which polar components are introduced into highly dispersible components through copolymerization reactions, addition reactions, etc., include materials in which sulfonate groups or amino groups are introduced into long-chain alkylphenols or higher esters of acrylic acid, for example. is known. However, compared to these materials, polyaminopolybutenyl succinimide seems to have superior solubility and adsorption power, and exhibits far superior control effects.

Furthermore, a major feature of polyaminopolybutenyl succinimide is that it is extremely stable and durable, but this is because polyaminopolybutenyl succinimide has extremely little effect on lowering the resistance of the carrier fluid. This seems to be caused by. In other words, if the amount necessary to obtain the same control effect is added to the same developer, the conventional so-called charge control agent has a resistance of 10 ¹⁴ to 10 ¹⁵ Ω without additives.
Resistance of carrier liquid with cm 10 ¹² ~ 10 ¹¹ Ωcm
It will be lowered to However, the resistance of polybutenyl succinimide is only about 10 ¹⁴ Ωcm at most, and even when a large amount is added, the resistance of the carrier liquid is
It is about 10 ¹³ Ωcm.

In general, the so-called liquid development method has a resistance of 10 ¹¹ to 10 ¹² Ωcm.
If the liquid resistance is below, the load will be dissipated to the carrier liquid during development, causing problems such as the image becoming faint or blurred. Furthermore, it is known that the resistance of the carrier liquid gradually decreases as development is repeated, and with conventional control agents, even a small amount of use causes the liquid resistance to decrease before the image changes, causing so-called deterioration of the developer. It has happened. However, when polyaminopolybutenyl succinimide is used, even after repeated use, the developer resistance decreases only slightly and does not cause any change in the image.
This effect is thought to be due to the fact that polyaminopolybutenyl succinimide is not completely ionically dissociated in the carrier liquid like conventional control agents.

Furthermore, polyaminopolybutenyl succinimide can be used extremely stably even when a developer is actually used in an apparatus. This is because polyaminopolybutenyl succinimide does not have double bonds or reactive groups such as sulfonate groups, and has no corona charge.
This is because it is extremely stable in an ozone atmosphere, which is another major feature not found in conventional control agents.

In order to form a developer using polyaminopolybutenyl succinimide, polyaminopolybutenyl succinimide is added to a toner particle dispersion liquid made of a coloring substance such as carbon black and a binder resin, as in the past. may be added in the form of a carrier solution.

The material constituting the toner particles is not particularly limited, and colorants include carbon black such as furnace black and channel black;
Various pigments and dyes can be used, and binder resins include acrylic polymers and copolymers such as polymethyl methacrylate, polystearyl methacrylate, and polylauryl methacrylate, polystyrene, polyvinyltoluene, poly(styrene-butadiene), etc. styrenic polymers and copolymers,
It is freely selected from halogen-containing polymers such as polyvinyl chloride and polyvinylidene chloride, rosin-based resins such as rosin-modified maleic acid and rosin-modified pentaerythritol, phenolic resins, styrene-based resins, and the like.

When polyaminopolybutenyl succinimide is used as a developer, the appropriate amount is
The amount is 0.001-1% (more preferably 0.005-0.5%). When actually applied to a copying machine, replenishment is performed in the form of a condenser containing a large amount of toner and a replenisher to absorb changes due to usage conditions, but in this case either or both contain polyaminopolybutenyl. Succinimide is added so that the effect does not change significantly even if the usage conditions change. Even in such cases, since polyaminopolybutenyl succinimide has a wide appropriate range, it is extremely easy to always obtain consistent image quality.

Production Example 100 g of polybutenyl succinic anhydride obtained by maleating polybutene (trade name HV-100, manufactured by Furukawa Chemical Co., Ltd.) and 18 g of tetrastyrene pentamine are refluxed in a toluene solvent under a nitrogen atmosphere for 3 and a half hours. The reaction product was filtered under reduced pressure, the solvent was removed,
Furthermore, to remove unreacted amine, 180℃, 1mm
Distilled under reduced pressure under Hg conditions. The reaction product is N: 6.8
%, alkaline value: 159.0, molecular weight: 2110, and the characteristic absorption of the IR spectrum is C=0 stretching vibration,
1700cm ^-1 , 1760cm ^-1 1660cm ^-1 , N-H stretching vibration
There is a 3300cm ^-1 NH bending vibration of 1550cm ^-1 . The above produced substance is Isopar H (aliphatic hydrocarbon manufactured by Etsuso).
The control agent solution was prepared by diluting it to 10% in water.

Example 1 Super Betsukasite 1126 (rosin modified phenol) 50 parts by weight AC polyethylene #6 (low molecular weight polyethylene)
50 parts by weight Regal 400R (carbon black) 15 parts by weight Isopar H 250ml After mixing the above substances, heat them and confirm that they are completely and uniformly dispersed in a solution, then cool them separately.
The mixture was mixed with 500 ml of Isopar H and finely dispersed, and this liquid was further dispersed for 24 hv using a ball mill, and then an additional 500 ml of Isopar was added to obtain a condenser.

After 200 ml of this condenser was mixed and dispersed in Isopar 2, 2 ml of the polyaminopolybutenyl succinimide solution prepared in Production Example 1 was added to prepare a developer. When this developer was applied to a liquid development type transfer copying machine NP-6 manufactured by Canon Inc., a very clear and high density image (Dmax=1.2) was obtained.

When 10 ml of the above polyaminopolybutenyl succinimide solution was added to the above Condenser 1 and used as a refilling compactor, continuous copying was continued while controlling the concentration to always be constant, and the density did not change even after using 10,000 sheets. (Dmax=1.1)
The images were also clear.

When the initial developer was filtered and the resistance of the solution was measured, it was 4.2×10 ¹⁴ Ωcm. Furthermore, the resistance of the liquid after the durability test was 1.3×10 ¹⁴ Ωcm.

Example 2 Pentacite P423 (rosin-modified pantaerythritol manufactured by Nippon Reich) 10 parts by weight Hiwax 220P (low molecular polyethylene manufactured by Mitsui Petrochemical) 80 parts by weight DQDJ6169 (ethylene ethyl acrylate manufactured by Nippon Unicar) 5 parts by weight Raven 1040 (carbon manufactured by Columbia Carbon) Black) 15 parts by weight A toner was prepared from the above substance in the same manner as in Example 1, and a developer was prepared. On the other hand, Caronite Chemical
A developer was prepared by adding 2.5 ml of a 10% solution of Oloa 1200 (polyaminopolybutenyl succinimide) to Isopar H. When we added 5 ml of Conctner to a durability test, there was no change in the image up to 20,000 copies.

Example 3 Pentacite P423 10 parts by weight AC polyethylene #6 90 parts by weight DQDJ6169 5 parts by weight Raven 1040 25 parts by weight A toner was prepared using the above materials in the same manner as in Example 1. To this, 3 ml of a 10% solution of Isopar H of Oloa373A (polyaminopolybutenyl succinimide manufactured by Caronite Chemical Co., Ltd.) was added to prepare a developer.
When we added 10 ml of Conctner to a durability test, there was no change in the image up to 50,000 copies.

Claims (1)

[Claims] 1. An electrostatic latent image developer containing a carrier liquid, a colorant, a binder resin insoluble in the carrier liquid, and polyaminopolybutenyl succinimide.