JP3434530B2 - One-component developer and developing device using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-component developer used for visualizing an electrostatic latent image in an image forming process such as an electrophotographic system or an electrostatic recording system, and a method using the same.
Development device .

[0002]

2. Description of the Related Art In the image forming processes such as electrophotography and electrostatic recording, a two-component developer mainly containing toner particles and carriers has been widely used for visualizing an electrostatic latent image. Came. However, when the two-component developer is used for a long period of time, the carrier surface is contaminated by the toner particles and the mixing ratio of the carrier and the toner particles varies, so that the toner particles are charged by the carrier. Tended to become insufficient.

On the other hand, in recent years, a one-component type developer mainly composed of toner particles containing a binder resin, a colorant and the like has been attracting attention in place of the two-component type developer. Thus, in the image forming process using such a one-component developer, a uniform thin layer of the one-component developer is usually formed on the developer carrier, and this thin layer is conveyed by the developer carrier. After that, the electrostatic latent image is visualized. Therefore, in a one-component developer,
In order to form a uniform thin layer of the one-component developer on the developer carrier without agglomeration, it is required that the fluidity is particularly good. Further, in the one-component developer, since the toner particles need to be sufficiently charged without using a carrier, extremely excellent chargeability is also required. For this reason, with regard to conventional one-component type developers, studies have been actively conducted on additives capable of imparting excellent fluidity and chargeability. For example, a binder resin and a colorant are contained, A one-component type developer containing hydrophobic silica for improving the property and various charge control agents for improving the charging property has been developed.
However, these one-component type developers still do not fully satisfy the fluidity and the chargeability, and there is a problem that it is difficult to obtain an image with less fog especially in a high humidity environment. Further, a paraffin wax that is a solid hydrocarbon is added as an additive during the melt-kneading of the binder resin and the colorant, and the fixing property of the one-component developer is
Attempts have also been made to improve offset resistance,
Even with such a technique, the fluidity and charging property of the one-component developer could not be improved so much.

[0004]

As described above, it is difficult to obtain an image with less fog in a high-humidity environment with the conventional one-component type developer, and further improvement in fluidity and charging property is desired. It was rare. An object of the present invention is to solve such problems and to provide a one-component type developer which has good fluidity and chargeability, and is capable of always forming an image with little fog without being affected by the external environment.

[0005]

One-component developer of the means and functions to an aspect of the present invention, the non-containing at least a binder resin and a colorant
The toner is mainly composed of magnetic toner particles, and 0.5 to 3.0 wt% of a non- volatile hydrocarbon which is liquid and non-volatile at room temperature and normal pressure is internally added to the non-magnetic toner particles. . That is, the present invention enhances the dispersibility of the colorant in the toner particles and the hydrophobicity of the toner particles by internally adding a liquid hydrocarbon to the toner particles, and thus improves the fluidity and chargeability of the one-component developer. It is to improve.

The one-component developer of the present invention will be described in detail below. The binder resin that can be used in the present invention is not particularly limited as long as it is contained in toner particles, and polystyrene, polyester, unsaturated polyester, polyethylene, epoxy resin, acrylate resin, and methacrylate are generally used. Examples thereof include resins, silicone resins, polypropylene, fluororesins, polyamide resins, polyurethane resins and copolymers thereof.
These may be used alone or in combination of two or more. As the colorant, all known dyes and pigments, for example, carbon black, phthalocyanine blue, indanthrene blue, peacock blue, lake red, permanent red, rhodamine lake, Hansa yellow, permanent yellow, benzidine yellow, etc. Alternatively, two or more kinds may be mixed and used. It should be noted that such a colorant is usually mixed in the binder resin in an amount of about 0.1 to 10 wt%. If the blending amount of the colorant is less than 0.1 wt%, the image density of the formed image may be low, and if the blending amount of the colorant exceeds 10 wt%, it becomes difficult to produce toner particles. Because it will be.

In the present invention, the hydrocarbon internally added to the toner particles is not particularly limited as long as it is a liquid and non-volatile at normal temperature and pressure, and saturated or unsaturated aliphatic hydrocarbon, saturated or It may be either an unsaturated alicyclic hydrocarbon or an aromatic hydrocarbon. Further, it is not necessarily required to be a pure and single-component hydrocarbon, and a substance containing a small amount of a sub-component or a mixture of a plurality of types of hydrocarbons is acceptable. For example, the main component is a liquid at room temperature and normal pressure and is non-volatile. As long as it is a hydrocarbon, a lubricating oil such as engine oil or machine oil, liquid paraffin, or the like can be used. However, in the present invention, the kinematic viscosity at 37.8 ° C. is 2.0 to 6.
It is preferable to use a hydrocarbon having a viscosity of about 0 mm ² / s.

In the one-component developer of the present invention, since the above-mentioned hydrocarbon can be used as the dispersion medium of the colorant at the time of producing the toner particles, the toner particles having a good dispersibility of the colorant. It is possible to improve the chargeability of the one-component developer and form an image with excellent color tone. Moreover, since such a hydrocarbon has a low polarity, the toner particles to which the hydrocarbon is internally added have increased hydrophobicity, and as a result, the characteristic change of the one-component developer under a high humidity environment can be prevented, It is possible to form an image that is not affected by the external environment.

In the present invention, when the binder resin, the colorant and the like are melt-kneaded to produce the toner particles, the hydrocarbons are blended and kneaded at the same time so that the hydrocarbons are internally added to the toner particles. It Specifically, a binder resin, a colorant, a hydrocarbon and, if necessary, other additives are mixed, and a double-arm kneader, a triple roll, a kneader, and a pressure kneader are mixed. -Melting and kneading with the like, and then crushed with a crusher such as a hammer mill, jet mill, and ball mill, and the obtained powder is classified with a sieve, an air classifier, etc., preferably 50% volume average Toner particles having a diameter of about 5 to 15 μm are manufactured. At this time, if the particle size of the toner particles is made too small, it becomes difficult to control the characteristics such as fluidity in the one-component developer, and conversely, if the particle size of the toner particles is too large, the resolution of the image formed decreases. Tend to do.

Generally, as a method of compounding the additives, as described above, the binder resin and the colorant are melted and kneaded at the same time when the toner particles are manufactured, and the internal addition method in which they are simultaneously kneaded and the toner particles are manufactured. Although there is an external addition method in which mixing and stirring are performed later, in order to obtain a one-component developer which has good fluidity and chargeability and can always form an image with less fog in the present invention, it is liquid and non-volatile at room temperature and atmospheric pressure. It is necessary to blend the above hydrocarbons by the internal addition method. That is, Japanese Patent Publication No.
JP-B No. 52-30855 and JP-B No. 52-30855 report that an image free from fog can be obtained by externally adding liquid paraffin, which is a non-volatile hydrocarbon, to a two-component developer. However, when the hydrocarbon is externally added in this way, the cohesiveness tends to increase and the fluidity tends to decrease, so that it cannot be applied to the one-component developer which requires particularly excellent fluidity as described above. Moreover, the external additive method
When the particles are manufactured, the dispersibility of the colorant cannot be increased to improve the charging property, etc., and the hydrocarbons easily fall off due to the surface peeling of the toner particles due to external factors such as friction, It is difficult to form an image with less fog over a long period of time. On the other hand, in the one-component developer of the present invention in which the liquid and non-volatile hydrocarbons are internally added to the toner particles at room temperature and atmospheric pressure, the hydrocarbons are uniformly dispersed even inside the toner particles. Also, since this hydrocarbon is non-volatile, it is stabilized in the toner particles. Therefore, even if the surface separation of the toner particles as described above occurs, the hydrocarbon bleeds from the inside of the toner particles and exerts its effect again,
The fluidity and chargeability of the one-component developer do not deteriorate at all, and it is possible to always form an image with less fog.

In the one-component developer of the present invention, the content of the above-mentioned hydrocarbon is preferably 0.5 to 3% by weight. The reason for this is that if the hydrocarbon content is less than 0.5 wt%, the reduction of fog in the formed image is small, and conversely, if it exceeds 3 wt%, an image with less fog can be formed. This is because the fluidity of the component-based developer tends to decrease, and the image density of the image formed tends to decrease.

Further, in the present invention, an additive such as a charge control agent or hydrophobic silica can be added internally or externally. According to the one-component developer of the present invention, magnetic powder such as magnetite can be blended in toner particles to be used in the one-component magnetic development system, but it is used in the one-component non-magnetic development system. Is more preferable. Needless to say, the one-component developer of the present invention may be either a positive charging type or a negative charging type.

[0013]

EXAMPLES Examples of the present invention will be shown below. Examples 1 to 5 and Comparative Example 1 First, 975 g of a styrene-acrylic copolymer (manufactured by Mitsui Toatsu Almatex Co., Inc.) was used as a binder resin, and 25 of a black pigment carbon black MA-11 (manufactured by Mitsubishi Kasei) was used as a colorant.
g When preparing and melting and kneading these with a pressure kneader,
Table 1 shows n-tetradecane (manufactured by Wako Pure Chemical Industries, Ltd.) as a non- volatile hydrocarbon that is liquid, non-volatile at room temperature and atmospheric pressure.
The ingredients were blended so as to have the content shown in, and kneading was continued for 30 minutes. Next, these kneaded materials are cooled and coarsely pulverized by a hammer mill, finely pulverized by a jet mill, and further classified by an air classification method to obtain a one-component developer of the present invention having a 50% volume average diameter of about 10 μm. Got Also, for reference, Comparative Example 1 which is completely the same except that n-tetradecane was not added.
A one-component type developer was also manufactured.

Next, using the thus obtained one-component developer, a test image was output by a one-component non-magnetic developing device for negative charging (Rhodry 3301 remodeled by Toshiba). Of the output test image, the density of the solid image part was measured with a Macbeth reflection densitometer (RD-918 type), while the color difference between the non-image part and the white background of the reference was measured with the Minolta colorimeter. The density and fog were evaluated. Further, in the negative charging one-component non-magnetic developing device,
Measuring the amount of electric charge generated when a thin layer of a one-component developer uniformly formed on the surface of the developer carrier is sucked by a suction means by rotating the developer carrier in the form of a lath at a constant speed. Thus, the chargeability of each one-component developer was evaluated. A molten film having a thickness of about 10 μm was prepared for each one-component developer, and an optical micrograph (× 20
From 0), 100 agglomerated particles of the colorant were randomly selected, the diameter in the major axis direction was measured, and the average value was calculated to evaluate the dispersibility of the colorant. However, the above evaluations are all vapor pressure 1
It was performed in an environment of 0 mmHg. The results are shown in Table 1. Regarding the dispersibility of the coloring agent in the table, the average value of the major axis diameters of the agglomerated particles of the coloring agent is 10 μm or more × 5 μm or more 1
It is judged as Δ when it is less than 0 μm and as ◯ when it is less than 5 μm.

[0015]

[Table 1]

As is clear from Table 1, in the one-component type developers of Examples 1 to 5, by adding n-tetradecane as a liquid non-volatile hydrocarbon in the toner particles at room temperature and normal pressure, Both the charging property and the dispersibility of the colorant were improved, and an image with less fog could be formed by the above-mentioned one-component non-magnetic developing device for negative charging. Further in FIG.
The relationship between the image density and fog in the formed image and the content of n-tetradecane is shown. As shown in FIG. 1, the content of n-tetradecane is 0.5 to 3.0 wt%.
In this case, it can be seen that it is possible to form an image with a particularly high image density and less fog. Examples 6 to 10 and Comparative Example 2 Exactly the same as Examples 1 to 5 and Comparative Example 1 except that the blue pigment KET Blue 104 (manufactured by Dainippon Ink & Co., Inc.) was used as the colorant instead of carbon black MA-11. Thus, one-component developers of Examples 6 to 10 and Comparative Example 2 were obtained. Further, regarding the obtained one-component type developer, Example 1
The image density, fog, chargeability and dispersibility of the colorant were evaluated in the same manner as in Comparative Example 1. The results are shown in Table 2.

[0017]

[Table 2]

As is clear from Table 2, in the one-component type developers of Examples 6 to 10, n-tetradecane was internally added to the toner particles as a non-volatile hydrocarbon which was liquid at room temperature and normal pressure. Both the charging property and the dispersibility of the colorant were improved, and an image with less fog could be formed by the above-mentioned one-component non-magnetic developing device for negative charging. Further in FIG.
The relationship between the image density and fog in the formed image and the content of n-tetradecane is shown. As shown in FIG. 2, the content of n-tetradecane is 0.5 to 3.0 wt%.
In this case, it can be seen that it is possible to form an image with a particularly high image density and less fog. Examples 11 to 15 and Comparative Example 3 Instead of carbon black MA-11 as a colorant, a red pigment Hostaperm Pink-EBtra. VP
Example 11 to Example 5 are the same as Examples 1 to 5 and Comparative Example 1 except that 307 (manufactured by Hoechst) is used.
15 and a one-component developer of Comparative Example 3 were obtained. Regarding the obtained one-component type developers, Examples 1 to 5 and Comparative Example 1
The image density, fog, chargeability, and dispersibility of the colorant were evaluated in the same manner as in. The results are shown in Table 3.

[0019]

[Table 3]

As is apparent from Table 3, in the one-component type developers of Examples 11 to 15, n-tetradecane was added as toner to the toner particles at room temperature under normal pressure as a nonvolatile hydrocarbon. Both the charging property and the dispersibility of the colorant were improved, and an image with less fog could be formed by the above-mentioned one-component non-magnetic developing device for negative charging. Further, in FIG. 3, the image density and the fogging and n− in the formed image are shown.
The relationship with the content of tetradecane is shown. As shown in FIG. 3, the content of n-tetradecane is 0.5 to 3.0 w.
It can be seen that when t%, it is possible to form an image with a particularly high image density and less fog. Examples 16 to 20, Comparative Example 4 Exactly the same as Examples 1 to 5 and Comparative Example 1 except that the yellow pigment KET Yellow 403 (manufactured by Dainippon Ink & Co., Inc.) was used as the colorant instead of carbon black MA-11. Thus, one-component type developers of Examples 16 to 20 and Comparative Example 4 were obtained. Further, with respect to the obtained one-component type developer, the image density, fog, charging property and dispersibility of the colorant were evaluated in the same manner as in Examples 1 to 5 and Comparative Example 1. The results are shown in Table 4.

[0021]

[Table 4]

As is clear from Table 4, in the one-component type developers of Examples 16 to 20, charging was carried out by internally adding n-tetradecane as a non-volatile hydrocarbon which is a liquid and under normal temperature and pressure in the toner particles. And the dispersibility of the colorant were improved, and it was possible to form an image with less fog by the non-magnetic developing device for the position component for negative charging. Further, in FIG. 4, the image density and the fog and n− in the formed image are shown.
The relationship with the content of tetradecane is shown. As shown in FIG. 4, the content of n-tetradecane is 0.5 to 3.0 w.
It can be seen that when t%, it is possible to form an image with a particularly high image density and less fog. Examples 21 and 22, Reference Example 1 , Comparative Example 5 Epoxy resin SR-3888 (manufactured by Mitsui Petrochemical Co., Ltd.) as a binder resin, and a red pigment PermanentP as a colorant.
Example 1 except that ink-FBL (manufactured by Sanyo Dye Co., Ltd.) was used as a machine-use lubricating oil Shell Terrace Oil C-220 (manufactured by Shell) as a non-volatile hydrocarbon that is liquid at room temperature and pressure.
5, in the same manner as in Comparative Example 1, a one-component developer of Example 21 and Reference Example 1 was obtained. In addition, a polyester resin ER-101 (manufactured by Mitsubishi Rayon) as a binder resin, a blue pigment Milori Blue-671 (manufactured by Dainichiseika) as a colorant,
Example 1 except that liquid paraffin (first-class reagent manufactured by Wako Pure Chemical Industries, Ltd.) was used as a non-volatile hydrocarbon that was liquid at room temperature and normal pressure.
~ 5, in the same manner as Comparative Example 1, Example 22 and Comparative Example 5
A one-component type developer was obtained. Further, with respect to the obtained one-component type developer, the image density, fog, chargeability and dispersibility of the colorant were evaluated in the same manner as in Examples 1 to 5 and Comparative Example 1. The results are shown in Table 5.

[0023]

[Table 5]

As shown in Table 5, the toner is also used in this case.
By internally adding liquid non-volatile hydrocarbons to the particles at room temperature and atmospheric pressure, both charging properties and dispersibility of the colorant can be improved, and images with less fog can be formed. It was confirmed that a high image density can be obtained when is 0.5 to 3.0 wt%.

[0025]

As described in detail above, the one-component type developer of the present invention has good fluidity and chargeability, and can always form an image with less fog without being affected by the external environment. It has great industrial value.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing the relationship between image density and fog in a formed image and the content of n-tetradecane in an example of the present invention.

FIG. 2 is a characteristic diagram showing the relationship between image density and fog in a formed image and the content of n-tetradecane in another example of the present invention.

FIG. 3 is a characteristic diagram showing the relationship between the image density and the fog and the content of n-tetradecane in a formed image in still another example of the present invention.

FIG. 4 is a characteristic diagram showing the relationship between the image density and the fog and the content of n-tetradecane in a formed image in another example of the present invention.

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-59-187356 (JP, A) JP-A-2-240662 (JP, A) JP-A 58-10750 (JP, A) JP-A-4- 250460 (JP, A) JP 54-8534 (JP, A) JP 63-192055 (JP, A) JP 3-63660 (JP, A) JP 44-32470 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 9/08

Claims (2)

(57) [Claims] 1. A one-component developer mainly composed of non-magnetic toner particles containing at least a binder resin and a colorant, wherein the non-magnetic toner particles are liquid and non-volatile under normal temperature and normal pressure. And non-polar hydrocarbon is 0.5-3.0w
A one-component developer characterized by being internally added at t%. 2. A one-component developer mainly composed of non-magnetic toner particles containing at least a binder resin and a colorant, wherein the non-magnetic toner particles are liquid and non-volatile at room temperature and atmospheric pressure. And non-polar hydrocarbon is 0.5-3.0w
A developing device using a one-component developer internally added with t%.