JPH0458627B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for developing an electrostatic image formed on the surface of an electrostatic image carrier, and particularly to a method for developing an electrostatic image formed on the surface of an electrostatic image carrier. It relates to a method of forming and developing a layer.

Conventionally, saturation magnetization was 10 emu/g in an external magnetic field of 5000 O¨e.
The following methods are known as developing methods using single-component toners that do not have magnetism or have weak magnetism. The first method includes a movable toner carrying means that carries and conveys the toner and supplies it to a latent image (electrostatic image) holder, and a toner replenishing means that applies the toner to the movable toner carrying means. a movable applicator, the movable applicator having a fiber brush that carries toner on its back surface, which abuts the movable toner carrier and moves at a higher speed than the movable toner carrier in this abutting portion; Prepare,
uniformly applying toner to the surface of the movable toner carrying means using the movable application means to form a toner coating layer;
This is a method of developing by bringing this coating layer close to the electrostatic latent image area.

The second method uses a rotatable magnetic roller that attracts a magnetic carrier to charge toner particles to form a magnetic brush, and transfers the toner particles from the roller to form an electrostatic image on an electrostatic image carrier. A developing roller is provided for developing the electrostatic image, and a gap is maintained between the electrostatic image holder and the developing roller in the developing section, and the gap length is set larger than the thickness of the toner coating layer on the developing roller. This is a method of developing.

The third method is to pump up the toner under the toner carrier stored in the toner storage means onto the toner carrier, and activate it by applying vibration to only the pumped-up portion of the toner, so that a predetermined amount of toner is applied to the surface of the toner carrier. In this method, a toner layer having a thickness of 1 is formed, and an electrostatic image on the surface of the electrostatic image carrier is developed by placing a toner carrier carrying this toner layer facing the electrostatic image carrier.

However, these methods are methods in which the insulating toner is carried on a carrier mainly by non-magnetic force in the developing section and developed. Electrostatic attraction and physical adhesion force are dominant, and this has various disadvantages compared to the conventional developing method using insulating magnetic toner, in which toner is supported on a carrier by magnetic force, electrostatic force, etc. occurs. For example, a phenomenon occurs that many toners are not applied relatively thinly and uniformly on the carrier. Furthermore, for example, even if the toner is applied relatively uniformly, toner adheres to non-image areas, resulting in so-called background fog. Furthermore, even if 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, even when applied thinly and evenly, can produce very poor images with low fidelity and low resolution. Furthermore, repeated use of more toner results in decreased image density and lower quality images.

However, even though there are such problems to be solved, in developing methods using one-component magnetic toner, magnetic toner particles contain a large amount of magnetic powder, so non-magnetic or weakly magnetic toner can be used. Since it is not only more expensive than conventional toners, but also difficult to produce beautiful colors, there is a great demand for a developing method using toner that is insulative and substantially non-magnetic.

An object of the present invention is to provide a new developing method using an insulating specific magnetic or weakly 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 the above-mentioned developing method which has excellent durability such as continuous use characteristics.

Another object of the present invention is to provide the above-mentioned developing method which provides images with sharp hues.

The present inventors investigated various developing methods using conventionally known non-magnetic or weakly magnetic toners, and found that in order to solve the above-mentioned drawbacks, compared to the developing method using magnetic toner, It was discovered that more precise control of the amount of electrostatic charge possessed by the toner on the toner carrier is important. That is, in a developing method using an insulating and substantially non-magnetic toner, for example, if the amount of charge is low, the toner will not be uniformly coated on the toner carrier, and development will not be possible. ,
Even if the coating is applied evenly, if the value is not appropriate, background fogging will easily occur.
On the other hand, if the value is too high, the electrostatic attraction with the toner carrier will be too strong, making it difficult for the toner to transfer to the electrostatic image carrier, resulting in a decrease in image density and the appearance of low-quality images. I end up having to wake him up. Furthermore, for the same reason, image quality is greatly affected by changes in toner charge amount due to repeated use. Therefore, it is extremely important to ensure the stability of the amount of charge.

From this point of view, the present inventors conducted extensive research and found that by incorporating a resin having a quaternary ammonium salt in the side chain into the toner, the amount of charge of a non-magnetic or weakly magnetic toner becomes extremely stable. , which led to the present invention.

Specifically, in the present invention, a toner carrier carrying an insulating non-magnetic toner on its surface is opposed to an electrostatic image carrier holding an electrostatic image on its surface with a certain distance between them in a developing section. Place it using the following general formula [] [R ₁ : Hydrogen or lower alkyl group R ₂ : At least one of C ₁ to _{C 12} alkylene group, phenyl group, naphthyl group, or nitrogen-containing unsaturated heterocycle R ₃ , R ₄ , R ₅ : Hydrogen lower alkyl group Or phenyl group The toner is tribo-electrified, and a toner layer of the tribo-charged insulating non-magnetic toner is formed on the toner carrier to a thickness thinner than the gap, and the insulating non-magnetic toner is charged with the electrostatic charge in the developing section. The present invention relates to a developing method characterized by developing an electrostatic image by transferring it to a holder.

In the developing method of the present invention, the reason why the toner containing the resin achieves the desired effects such as realizing high-resolution development is not clear in detail, but the quaternary ammonium salt is This is thought to be due in part to the fact that the electrical polarity is clearly ionized, unlike those that have electrical polarity simply due to the bias of the electrons on the molecule; One reason is that due to the rapid ionization, the electrical resistance of the resin decreases due to the movement of counter ions, and a good balance is achieved between charge accumulation due to toner friction and discharge due to lower resistance. .

By using such a developing method, it is possible to obtain a chromatic toner having a stable positive charge, and it has become possible to take out images with stable image quality over a long period of time even when used for a long period of time. In the developing method of the present invention, it is preferable to apply an alternating current and/or direct current bias between the toner carrier and the electrostatic image holder in the developing section, if necessary.

As the resin contained in the toner used in the developing method of the present invention, the following general formula [] [R ₁ : Hydrogen or lower alkyl group R ₂ : At least one of C ₁ to _{C 12} alkylene group, phenyl group, naphthyl group, or nitrogen-containing unsaturated heterocycle R ₃ , R ₄ , R ₅ : Hydrogen lower alkyl group Alternatively, phenyl group X: A copolymer of a vinyl compound represented by an organic anion such as a halogen anion or a carboxylate anion and styrene can be mentioned.

The resin has the following properties depending on its molecular weight, softening point, etc.
The content in the toner can be adjusted arbitrarily, but
Generally, it is good to include 2 parts by weight or more, more preferably 5 parts by weight or more in the total resin of the toner. If it is less than that, the charge stabilizing effect of this resin may not be reflected in the entire toner.

As for the other binder resins for the toner used in the developing method of the present invention, it is of course possible to use the above-mentioned resins alone as binder resins, but it is also possible to use one or more other resins in combination. It is also possible to use

For example, styrene copolymers such as polystyrene, polystyrene/butadiene copolymer, styrene/acrylic copolymer, ethylene copolymers such as polyethylene, polyethylene vinyl acetate copolymer, polyethylene vinyl alcohol copolymer, and phenolic copolymers. These include resins, epoxy resins, allyl phthalate resins, polyamide resins, polyester resins, maleic acid resins, and the like. Furthermore, there are no particular restrictions on the manufacturing method of any of the resins. As a result, resins conventionally produced by emulsion polymerization or the like that tend to contain impurities and are difficult to use can now be easily used, and the range of resin selection is greatly expanded.

If the toner is to have some magnetic properties as an supplement, magnetic fine particles may be added to the toner. Magnetic substances exhibit magnetism, but any material that can be magnetized may be used, such as metals such as iron, manganese, nickel, cobalt, and chromium, magnetite, various ferrites, manganese alloys, and other ferromagnetic alloys. Can be used in fine powder form.

As the charge control agent used in the present invention, all conventionally known ones can be used, such as oxidized starch, metal-containing dyes, salicylic acid metal complexes, nigrosine dyes, triphenylmethane compounds, rhodamine dyes, and phthalocyanine compounds. .

As the coloring material used in the toner of the present invention, conventionally known coloring materials such as carbon black, dyes, and pigments can be used.

Further, a fluidity improver such as silica or alumina may be added to the toner.

It is also possible to implement the above structure in the wall or the core or both in the microcapsule toner.

Hereinafter, the present invention will be explained in detail based on embodiments using figures.

FIG. 1 shows an example of an embodiment of an electrostatic latent image developing method and a developing device using an insulating toner. In the figure, 1
is a cylindrical electrostatic image holder, and an electrostatic latent image is formed on it by, for example, a known electrophotographic method such as the Carlson method or the NP method, and the insulation inside the hopper 3, which is a toner supply means, is The toner 5 is applied onto the toner carrier 2 by a coating means 4 that controls the thickness of the toner layer and is used for development.
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. Additionally, the developer roller may be made of an electrically conductive non-metallic material. Although not shown, spacer rollers made of high-density polyethylene are inserted into the shafts of both ends of the toner carrier 2. This spacer roller is attached to the electrostatic image holder 1.
By fixing the developing device against both ends of the electrostatic image carrier 1 and the toner carrier 2, the distance between the electrostatic image carrier 1 and the toner carrier 2 is set and maintained to be equal to or greater than the thickness of the toner layer coated on the toner carrier 2. This interval is, for example, 100μ~
500μ, preferably 150μ to 300μ. If this distance is too large, the electrostatic force exerted on the non-magnetic toner coated on the toner carrier 2 by the electrostatic latent image on the electrostatic image carrier 1 will be weak, and the image quality will deteriorate, especially due to the development of glue lines. Visualization becomes difficult. Moreover, if this distance is too narrow, there is a great risk that the toner applied on the toner carrier 2 will be compressed and aggregated between the toner carrier 2 and the electrostatic image holder 1.
Reference numeral 6 denotes a developing bias power source, which is capable of applying a voltage between the conductive toner carrier 2 and the back electrode of the electrostatic image holder 1. This developing bias voltage is a developing bias voltage as described in Japanese Patent Application No. 53-92108.

FIG. 2 is another example of the embodiment. In the figure, 1 is an electrostatic image carrier, 2 is a toner carrier, and 5 is a toner carrier.
3 indicates the toner specified in the present invention, 3 indicates a hopper, 9 indicates a cleaning blade, and 10 indicates a toner supply member. 16 is a vibration member, 17 is a vibration generating means, 16
16b is a support spring, 17a is an iron core, and 17b is a winding wire. By applying an alternating current to the winding 17b, the vibrating member 16 is vibrated at an appropriate amplitude and frequency, and a uniform toner coating layer is formed on the toner carrier 2 which is rotating at a constant speed, thereby separating the toner carrier 2 and the electrostatic image. The electrostatic image is developed by making the non-magnetic toner fly onto the electrostatic image by opposing the holder 1 with a gap larger than the thickness of the toner coating layer. 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, but if the thickness of the toner coating layer is 5 to 100 μm.
It is best to control the frequency and amplitude so that they are uniform. 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 another example of the embodiment. In the figure, 1 is an electrostatic image carrier, 2 is a toner carrier, 3 is a developer container, 5 is an insulating toner specified in the present invention,
6 is a developing bias power source, 9 is a toner cleaning member, 35 is a coating roller, 36 is a fiber brush fixed to the surface thereof, and 40 is a coating bias power source. Rotate the application roller 35 to apply the toner 5,
The toner is conveyed by a brush 36 to be uniformly applied onto the toner carrier 2, and is then flown onto the electrostatic image on the electrostatic image holder 1 to be developed. The gap between the toner carrier 2 and the application roller 35 is adjusted so as to form a uniform toner layer of about 5 to 100μ on the toner carrier 2, and the application bias power supply 40 is used to apply a bias voltage to ensure uniform toner application. may be applied. During development, a development bias may be applied from a development bias power source 6 so that the gap between the electrostatic image carrier 1 and the toner carrier 2 is larger than the toner layer thickness.

FIG. 4 is another example of the embodiment. In the figure, 1 is an electrostatic image carrier, 2 is a toner carrier, 5 is a one-component toner specified in the present invention, 43 is a developing device, 48 is a magnetic roller, 49 is a non-magnetic sleeve thereof, and 50 is a magnet. , 52 is a magnetic brush, and 53 is a one-component toner or a two-component developer in which a toner and a magnetic carrier are mixed. Non-magnetic sleeve 4
By holding a magnetic carrier on the toner carrier 2 by magnetic force to form a brush and rotating the sleeve 49, the toner or developer 53 is drawn up by the carrier brush and is applied in contact with the toner carrier 2, thereby forming a uniform toner layer 5. form. At this time, since the carrier is held on the magnetic roller 48 by magnetic force, it does not move onto the toner carrier 2. Next, the toner is developed by flying from the toner carrier 2 onto the electrostatic image holder 1. The gap between the magnetic roller 48 and the toner carrier 2 is such that the toner layer thickness on the toner carrier 2 is 5 to 100 μm.
Adjust to the desired degree. 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 to the toner carrier 2.

FIG. 5 is a diagram showing another example of the embodiment.
In the figure, 1 is an electrostatic image carrier, 2 is a toner carrier, 3 is a hopper, 6 is a bias power source for development, and 5 is a toner carrier.
1 shows the one-component toner specified in the present invention, 50 a fixed magnet, 52 a magnetic brush made of a carrier toner mixture, and 58 a toner thickness regulating blade. A 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 carrier 2 in a thin layer. Next, toner carrier 2
and the electrostatic image carrier 1 are opposed to each other with a gap larger than the toner layer thickness, and the one-component toner 5 on the toner carrier 2 is developed by flying onto the electrostatic charge image on the electrostatic image carrier 1. The thickness of the toner layer depends on the size of the magnetic brush 52,
That is, it is controlled by the carrier amount and the regulating blade 58. The gap between the electrostatic image carrier 1 and the toner carrier 2 may be made larger than the toner layer thickness, and a developing bias may be applied from the bias power source 6.

Specific examples will be described below, but the present invention is not limited by these examples.
In the following description, all parts are by weight.

Example 1 A non-magnetic toner having an average particle size of 11 μm was prepared by a conventional method, consisting of 100 parts of styrene-BMA-trimethylammonium chloride ethyl methacrylate copolymer (molar ratio 85:15:5) and 2 parts of rhodamine dye. This toner is shown in FIG.
When the toner carrier 2 was placed in a developing device made of a stainless steel cylindrical sleeve with an outer diameter of 20 mm, the toner was coated neatly onto the sleeve. This developing device was used with a Canon PC-10 copying machine, the distance between the photosensitive drum surface and the sleeve surface was set to 0.25, and an alternating current of 400 Hz, 1000 V and a direct current bias of -150 V were applied to the sleeve to perform development.

Next, the powder image was transferred while irradiating a DC corona of -7 kV from the back side of the transfer paper to obtain a duplicate image.

The resulting transferred image was sufficiently high, had no fogging, had no toner scattering around the image, and was a good image with high resolution. Durability was continuously examined using the above toner, and the transferred images after 10,000 sheets were also completely uncolored compared to the initial images.

Comparative Example 1 A non-magnetic toner having an average particle size of 11 μm was prepared by a conventional method, consisting of 100 parts of styrene-BMA-dimethylaminoethyl methacrylate copolymer (85:15:5) and 2 parts of rhodamine dye. When this toner was used in the same manner as in Example 1, the toner charge amount increased significantly after about 1000 sheets, and development became impossible.

Example 2 Styrene-BMA-trimethylammonium chloride ethyl methacrylate copolymer (85:15:5) 95 parts Styrene-BMA-sodium vinylcarboxylate complex copolymer 5 parts Rhodamine dye 5 parts Average particle size 12μ For the non-magnetic toner, the gap between the toner holder 2 and the application roller 35 was set to about 2 mm, and the length of the fiber brush 36 was set to about 3 mm. It is inserted into the developing device shown in Fig. 3, the gap between the developing roller and the electrostatic image holder is maintained at 200 μ, and a toner layer of about 30 μ is formed on the developing roller, and an alternating current waveform is generated at a frequency of 200 μ.
Similar good results were obtained by adding a DC component of -250 V to the peak voltage value of ±450 V in Hz to give peak voltage values of -700 V and +200 V.

Example 3 20g of the toner from Example 1 was added to 20g of iron powder carrier in advance.
The mixture was put into the developing device shown in Fig. 5, which was set so that the gap between the regulating blade 58 and the toner carrier 2 was about 250μ, and the mixture was put into the developing device shown in FIG.
Using a copying machine, the gap between the developing roller and the electrostatic image holder is maintained at 300μ, a toner layer of about 80μ is formed on the developing roller, and the DC component is -250V as an AC waveform with a frequency of 200Hz voltage at its peak value of ±450V. In addition,
Similar good results were obtained when developing at peak voltages of -700V and +200V.

[Brief explanation of the drawing]

1 to 5 are cross-sectional views showing different forms of a developing device used to carry out the developing method according to the present invention. 1... Electrostatic image carrier, 2... Toner carrier, 3
... hopper, 4 ... toner application means, 5 ... monocomponent toner, 6 ... development bias power supply, 9 ... toner cleaning blade, 10 ... toner supply member, 35 ... application roller, 36 ... fiber brush , 40... Bias power supply for application, 48... Magnetic roller, 49... Non-magnetic sleeve, 50... Permanent magnet, 52... Magnetic brush, 53... Developer, 5
8...Regulation blade.

Claims (1)

[Scope of Claims] 1. A toner carrier carrying insulating non-magnetic toner on its surface is disposed opposite to an electrostatic image carrier holding an electrostatic image on its surface with a certain distance in between. , the following general formula [] [R ₁ : Hydrogen or lower alkyl group R ₂ : At least one of C ₁ to _{C 12} alkylene group, phenyl group, naphthyl group, or nitrogen-containing unsaturated heterocycle R ₃ , R ₄ , R ₅ : Hydrogen lower alkyl group Or phenyl group triboelectrically charging the toner and forming a toner layer of the triboelectrically charged insulating nonmagnetic toner on the toner carrier to a thickness thinner than the gap, and the insulating nonmagnetic toner being triboelectrically charged in the developing section. A developing method characterized by developing an electrostatic image by transferring it to a holding body.