JPH0157906B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of developing an electrostatic image formed on the surface of an electrostatic image carrier, and particularly to a method of forming and developing a thin and uniform insulating nonmagnetic toner layer on a toner carrier. Conventionally, the following methods are known as developing methods using a one-component nonmagnetic toner. a movable developer carrying means that carries and conveys the developer and supplies it to the latent image carrier; a developer replenishing means; and a movable developer carrying means that receives the developer from the developer replenishing means and supplies the developer to the movable developer carrying means. A movable applicator for coating, which has a fiber brush that carries developer on its back surface, contacts the movable developer carrier, and moves a movable developer in the same direction as the movable developer carrier at this abutting portion. A method in which toner is uniformly coated on the surface of the movable developer carrier means using a movable coating means that moves at a higher speed than the developer carrier means, and development is carried out by bringing this coated layer close to the electrostatic latent image area. A rotatable magnetic roller that attracts a magnetic carrier to charge non-magnetic toner particles to form a magnetic brush, and a rotatable magnetic roller that transfers the toner particles from the roller to develop an electrostatic image on an electrostatic image carrier. A gap between the electrostatic image holder and the developing roller is maintained in the developing section, and the gap length is set larger than the thickness of the toner coating layer on the developing roller to develop the electrostatic image. and an electrostatic image developing method in which a developer holding member holding a developer on the surface thereof is opposed to the electrostatic image carrying member to develop an electrostatic image on the surface of the carrier. When pumping up the developer stored under the developer holder onto the developer holder, vibration is applied to only the developer in the pumped up portion to activate it, and a predetermined thickness of development is applied to the surface of the developer holder. There is a developing method in which a layer of agent is formed and then subjected to development. However, in the method of developing these insulating non-magnetic toners by supporting them on a carrier using non-magnetic force in the developing section, the force that causes the non-magnetic toner to be supported on the toner carrier around the developer is mainly electrostatic attraction. and physical adhesion is dominant,
In this respect, there are various drawbacks compared to the conventional developing method using insulating magnetic toner in which toner is supported on a carrier by magnetic force, electrostatic force, etc.
For example, a phenomenon occurs that many toners are not applied relatively thinly and uniformly on the carrier. Furthermore, for example, so-called background fog occurs in which toner adheres to non-image areas even though the toner is applied relatively uniformly. Furthermore, even though the toner is applied thinly and uniformly, the amount of toner adhering to the image area is insufficient, resulting in an image with low density. Additionally, many toners produce very poor images with low fidelity and low resolution even though they are applied thinly and evenly. Furthermore, repeated use of more toner results in decreased image density and lower quality images. Furthermore, many toners have the disadvantage that they sometimes cause a decrease in image density when subjected to environmental changes such as high temperature and high humidity, low temperature and low humidity, and sometimes cause background fog. In addition, in the development method using one-component magnetic toner, since the magnetic toner particles contain a large amount of magnetic powder, it is not only more expensive than non-magnetic toner, but also difficult to produce beautiful colors. It was difficult. An object of the present invention is to provide a new developing method using an insulating non-magnetic toner, which improves the above-mentioned drawbacks. That is, an object of the present invention is to provide a developing method with high fidelity and stable image quality. Another object of the present invention is to provide a developing method that eliminates the background fog phenomenon and provides a high-resolution image that is uniform and has sufficient density in the image area. Another object of the present invention is to provide a developing method with excellent durability such as continuous use characteristics. Another object of the present invention is to provide a developing method that is stable against environmental changes such as high temperature and high humidity, and low temperature and low humidity. Another object of the present invention is to provide a developing method that provides images with sharp hues. Specifically, an electrostatic image carrier that holds an electrostatic image on the surface and a positively charged insulating nonmagnetic toner in which silicone oil having an amine in the side chain is added to the toner particles are supported on the surface. A toner carrier is disposed with a certain gap between the toner carrier and the toner carrier, a positively charged insulating non-magnetic toner is carried on the toner carrier to a thickness thinner than the gap, and the toner is disposed in the developing unit with a certain gap between the toner carrier and the toner carrier. The present invention relates to a developing method characterized in that the image is transferred to an image holder and developed. Preferably, a developing method is used in which the toner is transferred while applying an alternating current and/or direct current bias between the toner carrier and the electrostatic image holder in the developing section. The present inventors investigated various developing methods using conventionally known non-magnetic toner, and found that in order to solve the above-mentioned drawbacks, compared to the developing method using magnetic toner, it is necessary to It has been found that more precise control of the amount of electrostatic charge possessed by toner is required. For example, if the amount of charge is low, a phenomenon occurs in which the toner is not evenly applied onto the carrier, and development cannot be achieved. Next, even if the amount of charge is increased to create a state where the toner is evenly applied, if the value is not appropriate, background fogging will easily occur, and conversely, if the value is too high, electrostatic interference with the toner carrier will occur. If the attractive force is too strong, it becomes difficult for the toner to transfer to the electrostatic image carrier, resulting in a decrease in image density and the appearance of a low-quality image. Furthermore, for the same reason, these developing methods have an extremely large effect on the image due to changes in the toner charge amount during repeated use or environmental changes, and ensuring the stability of the charge amount is more important than ever. In these development methods, the physical adhesion between the toner and the toner carrier clearly affects the transfer of the toner from the toner carrier. We have learned that when the packing density of toner particles in a layer is high, it is extremely important to prevent the physical adhesion from increasing, as this results in low-quality images with low image density and low resolution. Ta. The present invention achieves these characteristic requirements due to the method of developing an insulating non-magnetic toner by supporting it on a carrier using non-magnetic force in a developing section by using a toner containing a specific silicone oil. It is something. As the silicone oil having an amine in its side chain, silicone oil containing a structural unit represented by the formula () can generally be used. (Here, R ₁ is hydrogen, alkyl group, aryl group,
It represents an alkoxy group, R ₂ represents an alkylene group or a phenylene group, and R ₃ and R ₄ represent hydrogen, an alkyl group or an aryl group. However, the above alkyl group, aryl group, alkylene group, and phenylene group may contain an amine, or may have a substituent such as halogen within a range that does not impair chargeability. ) Preferred commercially available silicone oils having an amine in their side chains include, for example, amino-modified silicone oils represented by the following structural formula. it is (Here, R ₁ and R ₅ represent an alkyl group or an aryl group, R ₂ represents an alkylene group, a phenylene group, or an alkyl group containing an amine, and R ₃ represents hydrogen, an alkyl group, or an aryl group. m, n is a number of 1 or more.) Specifically, the following are preferred, and these may be used alone or in a mixture of two or more.

【table】

[Table] Manufactured by the company)
The amine equivalent in the above table is the equivalent per amine (g/eqiv), which is the value obtained by dividing the molecular weight by the number of amines per molecule. As mentioned above, especially when the amine equivalent is 25,000 or less (e.g., amine equivalent
320 to 8800) is preferred, and 5000 or less is particularly preferred. Further, it is preferable to use a silicone oil having a viscosity of 20 to 3,500 cps at 25° C. and having an amine as a chain marker in terms of positive charge control, environmental stability, and development characteristics. Since the modified silicone oil containing amino groups of the present invention is colorless or pale white, when applied to a positively charged color developer, a color developer with a very clear tone can be obtained. In addition, the modified silicone oil containing amino groups of the present invention is stable and has a heat resistance temperature of about 300°C, so it is extremely unlikely to decompose or change in quality due to thermal or mechanical shock, and has excellent charge controllability. There is no problem such as a decrease in the toner, and toner deterioration during durability is significantly reduced. Furthermore, the modified silicone oil containing amino groups of the present invention has strong positive chargeability and high humidity stability, so it has good positive chargeability even under high humidity.
A clear image can be obtained. In the present invention, a modified silicone oil containing amino groups can be added to the toner, and favorable results are obtained when 0.01 to 30% by weight is used, particularly when 0.02 to 10% by weight is used. , gives particularly good results. Examples of the binder resin of the toner that can be used in the present invention include monopolymers of styrene and substituted products thereof such as polystyrene, polyP-chlorostyrene, and polyvinyltoluene; styrene-P-chlorostyrene copolymers, and styrene-propylene copolymers. Copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate Copolymer, styrene
Methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-alpha chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer Copolymer, styrene-vinylethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer , styrenic copolymers such as styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin , rosin, modified rosin, terpene resin, phenolic resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. can be used alone or in combination. Coloring materials used in toner include known dyes and pigments such as carbon black, phthalocyanine blue, indanthrene blue, peacock blue,
Permanent red, lake red, rhodamine lake, Hansa yellow, permanent yellow, benzidine yellow, etc. can be widely used. The present invention will be explained in detail below using figures and examples. FIG. 1 is an explanatory diagram showing an example of an embodiment of an electrostatic latent image developing method using an insulating nonmagnetic toner.
In the figure, 1 is a cylindrical electrostatic image holder;
For example, the Carlson method, which is a known electrophotographic method, or
An electrostatic latent image is formed on this using the NP method,
The insulating non-magnetic toner 5 in the hopper 3, which is a toner supply means, is applied onto the toner carrier 2 by the application means 4 with the thickness of the toner layer regulated.
Develop it with The toner carrier 2 is a cylindrical developing roller made of stainless steel. The developing roller may be made of aluminum or other metals. Alternatively, a metal roller coated with resin or the like may be used in order to triboelectrically charge the toner to a desired polarity. Further, the toner application means 4 may be a blade as shown in FIG. 1, or may be an elastic roller. When the application means 4 is an elastic roller, the amount of toner charge on the carrier can be changed by changing the pressing pressure of the elastic roller against the toner carrier. Moreover, the electrostatic image carrier 1
It is preferable that the distance between the toner carrier 2 and the toner carrier 2 is set to be greater than or equal to the thickness of the toner layer coated on the toner carrier 2. Furthermore, it is preferable that a bias power source as shown in 6 is provided and a developing bias is applied between the electrostatic image carrier 1 and the toner carrier 2. FIG. 2 is an explanatory diagram of another example. In the figure, 1 is an electrostatic image carrier, 2 is a toner carrier, 5 is toner, 3 is a hopper, 16 is a vibration member, 17 is a vibration generating means, 16a is a permanent magnet, 19 is a cleaning blade, and 10 is a toner. A supply member is shown. That is, the vibrating member 16 is vibrated with an appropriate amplitude and frequency to form a uniform toner coating layer on the toner carrier 2 rotating at a constant speed, and the toner carrier 2 and the electrostatic image carrier 1 are The electrostatic image is developed by facing the electrostatic image with a gap larger than the thickness of the toner coating layer, and causing the non-magnetic toner to fly onto the electrostatic image. The vibration of the vibrating member 16 may be at any level as long as it does not come into direct contact with the toner carrier 2. It is also possible to apply an AC and/or DC developing bias voltage between the toner carrier 2 and the electrostatic image holder 1. FIG. 3 is an explanatory diagram of another example. In the figure, 1 is an electrostatic image carrier, 2 is a toner carrier,
35 is a coating roller, 36 is a fiber brush fixed to its surface, 6 is a developing bias power source, 38 is a developing device, 9 is a toner cleaning member, and 40 is a coating bias source. That is, toner No. 5 is uniformly applied onto the toner carrier 2 by rotating an application roller No. 35 and conveyed by a brush No. 36, and is caused to fly onto the electrostatic image No. 1 to be developed. The gap between the toner carrier 2 and the application roller 35 may be adjusted so as to form a uniform toner layer on the toner carrier 2, and a bias voltage indicated by 40 may be applied to uniformly apply the toner. The gap between the electrostatic image carrier 1 and the toner carrier 2 may be made larger than the above-mentioned toner layer thickness, and a developing bias of 6 may be applied during development. FIG. 4 is an explanatory diagram of another example. In the figure, 1 is an electrostatic image carrier, 2 is a toner carrier, and 4 is a toner carrier.
3 is a developing device, 5 is a one-component non-magnetic toner, 6 is a bias power supply, 48 is a magnetic roller, 49 is a non-magnetic sleeve, 50 is a magnet, 52 is a magnetic brush, 53
represents a one-component non-magnetic toner or a two-component developer in which a non-magnetic toner and a magnetic carrier are mixed.
That is, a magnetic carrier is magnetically held on a non-magnetic sleeve 49 to form a brush, and by rotating 49, the carrier brush 53 draws up the toner or developer 53 and contact-coats it onto the toner carrier 2. This forms a uniform toner layer. At this time, since the carrier is held on the toner carrier 48 by magnetic force, it does not move onto the toner carrier 2. Next, the nonmagnetic toner is transferred from the toner carrier 2 onto the electrostatic image carrier 1 and developed. The gap between the toner carrier 2 and the electrostatic image carrier 1 may be made larger than the toner layer thickness, and a developing bias voltage may be applied between the toner carrier 2 and the electrostatic image carrier 1. FIG. 5 is an explanatory diagram of another example. In the figure, 1 is an electrostatic image carrier, 2 is a toner carrier, and 3 is a toner carrier.
is a hopper, 52 is a magnetic brush using a carrier toner mixture, 58 is a blade for regulating toner thickness,
50 is a fixed magnet, 6 is a developing bias, and 5 is a one-component non-magnetic toner. That is, the magnetic brush 52 formed on the toner carrier 2 is circulated by rotating the toner carrier 2, takes in the toner in the hopper 3, and uniformly coats the toner 2 in a thin layer. Next, toner carrier 2
and an electrostatic image carrier 1 are opposed to each other with a gap larger than the toner layer thickness, and the one-component non-magnetic toner 5 on 2 is developed by flying onto the electrostatic charge image on 1. The total amount of charge in the toner layer can be controlled by the size or carrier amount of the magnetic brush 52 and the regulating blade 58. The gap between 1 and 2 may be made larger than the toner layer thickness, and a developing bias of 6 may be applied. Example 1 Styrene-butyl methacrylate (weight ratio 7:
3) 100 parts by weight of copolymer, 10 parts by weight of phthalocyanine blue pigment, 3 parts by weight of polyethylene wax,
Amino-modified silicone oil (viscosity at 25℃
70 cps, amine equivalent 830) and 1.2 parts by weight were mixed and melt-kneaded using a roll mill. After cooling, it is roughly pulverized in a hammer mill, and then finely pulverized in a jet pulverizer. Next, it was classified using an air classifier to obtain a fine powder with a particle size of approximately 5 to 20 μm. A toner was prepared by adding 0.4 parts by weight of colloidal silica to 100 parts by weight of this fine powder. Meanwhile, a mixture consisting of 100 parts by weight of zinc oxide, 20 parts by weight of styrene-butadiene copolymer, 40 parts by weight of n-butyl methacrylate, 120 parts by weight of toluene, and 4 parts by weight of 1% rose bengal methanol solution was dispersed in a ball mill for 6 hours. Mixed. This is 0.05
The coating was applied to a mm-thick aluminum plate using a wire bar to a dry coating thickness of 40 μm, and the solvent was evaporated with warm air to create a zinc oxide binder-based photoreceptor in the form of a drum. This photoreceptor was subjected to -6 KV corona discharge to uniformly charge the entire surface, and then an original image was irradiated to form an electrostatic latent image. The above toner was put into a developing device as shown in FIG. 1, and the electrostatic latent image described above was developed. Here, the toner carrier is a stainless steel cylindrical sleeve with an outer diameter of 50 mm, the distance between the photosensitive drum surface and the sleeve surface is set to 0.25 mm, and the sleeve has a 400Hz,
An alternating current of 1000V and a direct current bias of -150V were applied. Next, the powder image was transferred while irradiating -7 KV direct current corona from the back side of the transfer paper to obtain a copied image. For fixing, use a commercially available plain paper copier (product name, NP-
5000, manufactured by Canon). The resulting transferred image had a sufficiently high density of 1.5, no fogging, no toner scattering around the image, and a good blue image with high resolution. Durability was continuously investigated using the above developer.
The transferred image after 50,000 copies was also comparable to the initial image. In addition, when the environmental conditions were set to 35℃ and 85%, the image density was 1.40, a value that was almost unchanged from normal temperature and humidity, and a clear blue image was obtained without fogging or scattering, and the durability was up to 50,000 sheets. There was almost no change. Next, when a transferred image was obtained at a low temperature and low humidity of 10°C and 10%, the image density was as high as 1.40, solid black was developed and transferred extremely smoothly, and the image was excellent with no scattering or hollow spots. When durability was tested under these environmental conditions, the density fluctuation was ±0.2 up to 50,000 copies, which was sufficient for practical use, even though copies were made continuously and intermittently. Example row 2 Styrene-butyl methacrylate (weight ratio 7:
3) 100 parts by weight of copolymer, 10 parts by weight of phthalocyanine blue pigment, 4 parts by weight of polyethylene wax,
Amino-modified silicone oil (viscosity at 25℃
When the same procedure as in Example 1 was carried out except that 1 part by weight (3500 cps, amine equivalent 3800) was used, a clear blue image without fog was obtained. It also performed well under high temperature and high humidity conditions as well as under low temperature and low humidity conditions. Example 3 Styrene-butyl methacrylate (weight ratio 7:
3) 80 parts by weight of copolymer, 20 parts by weight of styrene-butadiene (weight ratio 85:15) copolymer, 5 parts by weight of phthalocyanine blue, 4 parts by weight of low molecular weight polypropylene
0.8 parts by weight of amino-modified silicone oil (viscosity 3500 cps at 25°C, amine equivalent 3800) were mixed and an image was obtained in substantially the same manner as in Example 1. A clear blue image without fogging was obtained. Examples 4 to 6 Amine equivalent and viscosity at 25°C are 2000 and 2000, respectively.
Good results were obtained in the same manner as in Example 1, except that amino-modified silicone oils of 3500 cps, 8800, 90 cps, 22500, and 60 cps were used. Example 7 When the toner of Example 1 is put into the apparatus shown in FIG. 2, the vibrating member 16 is vibrated at a frequency of about 50 Hz and an amplitude of 0.2 mm, and the toner carrier 2 is rotated at a circumferential speed of 120 mm/sec. A uniform toner coating layer with a thickness of about 50 μm was formed on the toner carrier. The toner carrier 2 and the electrostatic image holder 1 are placed facing each other with a gap of approximately 300 μm, and the toner carrier 2 has a frequency of several hundred to several kilograms.
Hz, a bias AC electric field of -600 to -1200 V at a negative peak value and -400 to +800 V at a positive peak value was used for development, and similar good results were obtained. Example 8 The toner shown in Example 1 was applied using a fiber brush 36 with a gap of about 2 mm between the toner carrier 2 and the application roller 35.
The toner was placed in the developing device shown in Figure 3 whose length was set to approximately 3 mm, the gap between the developing roller and the electrostatic image holder was maintained at 300 μ, and a toner layer of approximately 80 μ was formed on the developing roller. Similar good results were obtained by adding a direct current component of 250 V to the peak value ±450 V of a voltage with a frequency of 200 Hz as a waveform to give peak voltage values of +700 V and -200 V. Example 9 The toner of Example 1 was put into the developing device shown in FIG. 4, which was set so that the gap between the toner carrier 2 and the magnetic roller 48 was about 2 mm, and the maximum thickness of the magnetic brush 52 was about 3 mm. The gap between the developing roller and the electrostatic image holder is maintained at 300μ, a toner layer of approximately 80μ is formed on the developing roller, and the frequency is expressed as an AC waveform.
200Hz, voltage peak value ±450V and DC component 250V
Similar good results were obtained by applying peak voltages of +700V and -200V. Example 10 20g of the toner of Example 1 was added to iron powder carrier 20g in advance.
g, and the mixture is put into the developing device shown in FIG. 5, which is set so that the gap between the regulating blade 58 and the toner carrier 2 is about 250μ, and the gap between the developing roller and the electrostatic image carrier is was maintained at 300μ, a toner layer of approximately 80μ was formed on the developing roller, and developed by adding a DC component of 250V to the voltage peak value ±450V at a frequency of 200Hz as an AC waveform, giving a voltage peak value of +700V and -200V. However, similar good results were obtained. Comparative Examples 1 to 3 Examples 1 to 3 were carried out in the same manner as in Examples 1 to 3 except that the amino-modified silicone oil was not used, but only poor images were obtained. Comparative Example 4 Dimethyl silicone oil (viscosity at 25°C: 50 cps) was used instead of amino-modified silicone oil, which is a silicone oil with amine in the chain.
A toner was prepared in the same manner as in Example 1, except that a toner was used, and an image was produced in the same manner as in Example 1. The result was a poor image with a lot of fog and an image density of 0.5 or less. .

[Brief explanation of drawings]

1 to 5 are explanatory views showing examples of embodiments of a developing method using insulating nonmagnetic toner. DESCRIPTION OF SYMBOLS 1... Electrostatic image holder, 2... Toner carrier, 4... Coating means, 5... Toner, 6... Bias power supply.

Claims (1)

[Scope of Claims] 1. An electrostatic image carrier that holds an electrostatic image on the surface, and a positively charged insulating non-magnetic toner in which a silicone oil having an amine in a side chain is added to the toner particles on the surface. A toner carrying member to be carried is arranged with a certain gap in the developing section, positively charged insulating non-magnetic toner is carried on the toner carrying body to a thickness thinner than the gap, and the toner is placed in the developing section. A developing method comprising transferring the electrostatic image to the electrostatic image holder and developing the image. 2. The developing method according to claim 1, wherein an alternating current and/or direct current bias is applied between the toner carrier and the electrostatic image holder in the developing section.