JPH0344651A - Developer - Google Patents

Abstract

PURPOSE:To prevent the sticking of a toner to a sensor window by using the developer which contains a nonmagnetic toner contg. a specific pigment and binder resin and a resin coated carrier. CONSTITUTION:The developer which contains the nonmagnetic toner contg. at least the non-rake type insoluble azo pigment and 'C.I. Pigment Yellow 81(R)' and the binder resin and the resin coated carrier is used as the developer of a developing device having a device for automatic photodetection and control of the toner concn. Excessive electrostatic charge and the secure sticking of the toner to the carrier do not arise with the toner constituted in such a manner even if continuous copying is executed in low-temp. low-humidity environment. The electrostatic charge rising is fast and even the replenished toner immediately has the adequate electrostatic charge quantity by agitating and mixing with the carrier and, therefore, the toner does not stick to the window part of the toner sensor 20 and the stable control of the toner concn. to an adequate value is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is applicable to a developing device having a photo-sensing toner density control device in electrophotographic copying devices and electrostatic recording devices used for various purposes. This invention relates to color developers.

[Prior Art] In a developing device using a two-component developer consisting of toner and carrier, the mixing ratio of toner and carrier is an extremely important factor in terms of the developing effect. In other words, if the toner density is below the appropriate level, the image density will be low; if the toner density is above the appropriate level, the image density will be low; and if the toner density is higher than the appropriate level, the toner will not be sufficiently charged and fog will occur. This may cause other inconveniences. Therefore, in order to obtain a good image, it is necessary to accurately detect the developer concentration and control the toner concentration to an appropriate value.

Regarding toner density control (ATR) methods, various proposals have been made in the past, and one proposed in particular in Japanese Patent Publication No. 38-17245, etc. detects the color of the developer and controls the amount of toner replenishment. The means is a stable detection means that is not easily affected by changes in physical properties such as high density of the developer due to environmental changes or durability.

As a toner concentration detection section for the above photodetection ATR method, for example, the one shown in FIG. 5 is generally known. This is a lamp (light source) 1 that irradiates light onto the developer in the transport path A from a sensor window 13 made of a transparent material provided in a predetermined space in the transport path of the developer consisting of toner and carrier.
0, a first sensor 11 that receives the light reflected by the developer, and a second sensor 12 that directly receives the light from the lamp IO.

In this toner concentration detection method, the first sensor 11
receives the reflected light reflected by the developer and outputs the voltage,
The second sensor 12 directly receives the light from the lamp 10 and detects the toner concentration from the difference between the received light and the output voltage. In this photodetection ATR method, since the developer comes into contact with the toner concentration detection device, there is a problem that the detection device is scratched by the carrier. Therefore, the carrier is coated with resin on the surface that does not damage the sensor window surface. carriers are preferred.

However, a carrier whose surface is coated with a resin has a high electrical resistance, and when copying is continued in a low-humidity environment, the toner has an excessive charge and adheres firmly to the carrier surface.

Even if toner is newly replenished into the developer in this state, the replenished toner will not have a chance to come into contact with the carrier due to the toner adhering to the carrier, and will not be able to be sufficiently charged. , toner with a small amount of charge is
The developer adheres to the surface of the sensor window, which is charged to the opposite polarity to the toner.

When toner adheres to the sensor window, the ATR device malfunctions and controls the toner concentration of the developer below an appropriate value, resulting in problems such as a decrease in image density and fogging.

On the other hand, in current copying machines, the importance of copying in chromatic colors other than black is increasing.

It has been proposed to use a monoazo pigment as a coloring agent for chromatic toners, especially red toners (Japanese Patent Application Laid-Open No. 1986-56
-140357).

However, with a developer that combines a toner containing only these pigments and a resin-coated carrier, when continuous copying is performed in a low-humidity environment, the toner tends to adhere to the surface of the ATR sensor window, making it difficult to adjust the toner concentration of the developer to an appropriate level. It was difficult to control the value.

[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned conventional problems and to provide a developer suitable for a developing device having a photodetection automatic toner density control device.

[Means and Effects for Solving the Problems] As a result of intensive research, the present inventor has discovered that at least a non-lake-based insoluble azo pigment and a developer for use in a developing device having a photodetection automatic toner density control device have been developed. C,1,Pigme
By using a developer containing a non-magnetic toner containing nt Yellow 81 and a binder resin, and a resin-coated carrier, it is possible to prevent the toner from adhering to the sensor window, and
We have discovered that malfunctions of RT devices can be prevented.

The present invention will be explained in detail below.

The developer carrier used in the present invention is constructed by providing a coating layer made of resin on the surface of magnetic particles.

As the material of the carrier core material used in the present invention, for example, surface oxidized or unoxidized metals such as iron, nickel, cobalt, manganese, chromium, rare earths, and their alloys or oxides can be used, but preferably Metal oxides, more preferably ferrite particles can be used.

In addition, the surface of these ferrite particles can be coated with zinc oxide, manganese oxide, nickel oxide, etc., which have lower hardness than ferrite.
Ferrite particles coated with a metal oxide such as cerium oxide or tungsten oxide are more preferable because they are less likely to damage the ATR sensor window.

The average particle size of the carrier core material is generally preferably from 30 to 90 gm, more preferably from 35 to 70 pm. If the average particle size is less than 30 pm, the carrier is likely to be developed (transferred together with the toner) onto the latent image holding member, and the latent image holding member and the cleaning blade are likely to be damaged. On the other hand, if the average particle diameter of the carrier is larger than 70 pm, the toner retention ability of the carrier is reduced, and non-uniform solid images, toner scattering, fogging, etc. are likely to occur. Also, A
The surface of the TR sensor window will be easily damaged.

Further, such a carrier core material may be a mixture of two or more types of magnetic particles.

As the resin used for coating the carrier of the present invention, known resins can be used, but fluororesins and styrene resins are particularly preferred.

Examples of fluororesins include halofluoropolymers such as polyvinyl fluoride, polyvinylidene fluoride, polytrifluoroethylene, polytrifluorochloroethylene, polytetrafluoroethylene, polyperfluoropropylene, vinylidene fluoride, and acrylic monomers. copolymer with vinylidene fluoride and trifluorochloroethylene, copolymer with tetrafluoroethylene and hexafluoropropylene, copolymer with vinylidene fluoride and vinylidene fluoride, fluoride Fluoro terpolymers such as copolymers of vinylidene and tetrafluoroethylene, copolymers of vinylidene fluoride and hexafluoropropylene, terpolymers of tetrafluoroethylene and vinylidene fluoride, and non-fluorinated monomers, etc. Preferably used.

In order to impart sufficient chargeability to the toner, these fluoropolymers are preferably used in combination with other polymers, particularly styrene-acrylic polymers.

Also, the ratio of fluoropolymer to other polymer is 20:
80-80: 20% by weight is preferred. More preferably, it is 40:, 60:40 wt%.

In addition, the weight average molecular weight of the fluoropolymer is 50.000~
400.000 is preferred. More preferably 100.0
00-250.000.

On the other hand, styrene is a styrene resin.

α-methylstyrene, p-methylstyrene, p-t-
Styrenic monomers such as styrene derivatives such as butylstyrene and p-chlorostyrene are used.

Various other copolymerization components can be used, and acrylic monomers are particularly preferred. For example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, hebutyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, undecyl methacrylate, dodecyl methacrylate. , glycidyl methacrylate, methoxyethyl methacrylate, propoxyethyl methacrylate, butoxyethyl methacrylate, methoxydiethylene glycol methacrylate, ethoxydiethylene glycol methacrylate, methoxynigelyl gelyl methacrylate, butoxytriethylene glycol methacrylate, methoxydipropylene glycol methacrylate , phenoxyethyl methacrylate, phenoxydiethylene glycol methacrylate, phenoxytetraethylene glycol methacrylate, benzyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, dicyclopentenyl methacrylate, dicyclopentenyloxyethyl methacrylate, N- methacrylate Vinyl-2-pyrrolidone, methacrylonitrile, methacrylamide, N-
Methylol methacrylamide, ethyl morpholine methacrylate, diacetone acrylamide, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, acrylic polymer, hexyl acrylate, hebutyl acrylate, octyl acrylate, nonyl acrylate, Decyl acrylate, undecyl acrylate, dodecyl acrylate, glycidyl acrylate, methoxyethyl acrylate, propoxyethyl acrylate, butoxyethyl acrylate, methoxydiethylene glycol acrylate, ethoxydiethylene glycol acrylate, methoxyethylene glycol acrylate, butoxy acrylate Triethylene glycol, methoxydipropylene glycol acrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, phenoxytetraethylene glycol acrylate, acrylic, benzyl acid, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, dicyclopentenyl acrylate, acrylic dicyclopentenyloxyethyl acid, N-vinyl-2-pyrrolidone acrylate, glycidyl acrylate,
Reaction of vinyl monomers having one vinyl group in each molecule such as acrylonitrile, acrylamide, N-methylolacrylamide, diacetone acrylamide, ethylmorpholine acrylate, vinylpyridine, divinylbenzene, glycol and methacrylic acid or acrylic acid. products such as ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1
．． 4-butanediol dimethacrylate, 1.5-bentanediol dimethacrylate, 1.6-hexanediol diacrylate, neopentyl glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, tripropylene glycol dimethacrylate Methacrylate, hydroxypivalic acid neopentyl glycol ester dimethacrylate, trimethylolethane trimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, trismethacryloxyethyl phosphate,
Tris (methacryloyloxyethyl) isocyanurate.

Ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, L,4-butanediol diacrylate, 1,5-bentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate , triethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene diacrylate, hydroxypivalic acid neopentyl glycol diacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, trisacryloxyethyl phosphate, Tris (methacryloyloxyethyl) isocyanurate, half ester of glycidyl methacrylate and methacrylic acid or acrylic acid, half ester of bisphenol-type epoxy resin and methacrylic acid or acrylic acid, half ester of glycidyl acrylate and methacrylic acid or acrylic acid Acrylic monomers having two or more vinyl groups in one molecule such as compounds, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, hydroxybutyl acrylate, 2-hydroxy-acrylate
3-phenyloxypropyl, 2-hydroxylethyl methacrylate, 2-hydroxypropyl methacrylate,
Acrylic monomers having a hydroxyl group such as hydroxybutyl methacrylate and 2-hydroxy-3-phenyloxypropyl methacrylate can be mentioned.

Among the monomers, styrene, styrene derivatives, methacrylic esters, acrylic esters, etc. are preferable as monomers having one vinyl group in one molecule, and in particular methacrylic acid or acrylic acid having 1 to 5 carbon atoms in the alkyl group. Alkyl esters of acrylic acid are preferred. In vinyl monomers having two or more vinyl groups in one molecule,
Preferred are divinylbenzene, dimethacrylate and diacrylate made of methylene glycol having 2 to 6 carbon atoms, and the like.

In addition, the ratio of the styrene-based component to other components is the monomer ratio (styrene-based) = (other) = 100:O ~ 1
0:90, preferably 90:10-30:70
is good.

These vinyl monomers are copolymerized by known methods such as suspension polymerization, emulsion polymerization, and solution polymerization. These copolymers preferably have a weight average molecular weight of 10,000 to 70,000. This copolymer may also be crosslinked with melamine aldehyde or isocyanate.

As a method for coating the surface of the carrier core material with the coating resin, the resin is dissolved or suspended in a solvent and applied to the surface of the core material, and the resin is adhered to the core material made of magnetic particles or the like. The method is preferred.

The processing amount of the above-mentioned coating resin depends on the film-forming properties and durability of the coating material.
Generally, the total amount is 0.1 to 30% by weight based on the carrier core material,
Preferably it is 0.5 to 20% by weight.

The toner used in the present invention includes at least a binder resin, a non-lake-based insoluble azo pigment, and C.I.

Pigment Yellow81.

Non-lake type insoluble azo pigment and C, r, Pigment
The toner containing Yellow 81 uses a resin-coated carrier with high electrical resistance, so even when continuous copying is performed in a low-temperature, low-humidity environment, the toner does not become excessively charged and the toner firmly adheres to the carrier. There's nothing to put away.

Further, a non-lake type insoluble azo pigment, and C,I.

The toner containing Pigment Yellow 81 has a quick charge build-up, so that the replenished toner quickly acquires an appropriate amount of charge upon stirring and mixing with the carrier.

For the above reasons, toner does not adhere to the sensor window, and the toner concentration of the developer can be stably controlled to an appropriate value. On the other hand, a toner using a lake-based azo pigment has a slow charge build-up and is likely to wake up a person wearing a window.

Specific examples of non-lake-based insoluble azo pigments include C, 1, P
pigment Red 12, C, 1, Pigment
Examples include Red 18.

The content of the non-lake-based insoluble azo pigment is preferably 2 to 10 parts by weight based on 100 parts by weight of the binder resin. More preferably, it is 3 to 8 parts by weight.

Further, the content of C, 1, Pigment Yellow is preferably 0.1 to 5 parts by weight based on the binder resin.

More preferably, it is 0.3 to 3 parts by weight.

The binder resin for the toner used in combination with the carrier of the present invention as a two-component developer includes polystyrene, poly-
Styrene and its substituted monomers such as p-chlorostyrene and polyvinyltoluene; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer combination, 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-methacrylic acid Butyl copolymer, styrene-acrylic-aminoacrylic copolymer, styrene-aminoacrylic copolymer, styrene-α-methyl chloromethacrylate copolymer, styrene-acrylonitrile copolymer, styrene-
Vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene- Styrenic copolymers such as maleic acid copolymers and styrene-maleic ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resins , polyvinyl butyral, polyacrylic acid resin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc., either alone or in two types as necessary. The above can be used in combination.

Furthermore, a charge control agent and a fluidity modifier may be added as necessary, and the charge control agent and fluidity modifier may be mixed (externally added) with the toner particles.

As the charge control agent, metal-containing dyes, quaternary ammonium salts, nigrosine dyes, etc. are used.

Examples of fluidity modifiers include colloidal silica and fatty acid metal salts. Further, for the purpose of increasing the amount, fillers such as calcium carbonate and finely divided silica may be incorporated into the toner in an amount of 0.5 to 20% by weight. Furthermore, in order to prevent toner particles from coagulating with each other and improve their fluidity, a fluidity improver such as fine Teflon powder may be added.
For the purpose of improving mold releasability during hot roll fixing, about 0.5 to 5% by weight of a waxy substance such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, carnauba wax, Sasol wax, etc. can be added.

Note that the present invention is not limited to the examples listed here.

The toner structure described above may be used for a toner produced by the mixing-pulverization method used in -M, or may be used for a microcapsule toner.

A commonly used mixing method can be applied to the mixing method of the carrier and toner of the present invention, but the toner concentration is 3 to 3
It is preferable to contain 0 parts by weight (more preferably 5 to 25 parts by weight). Within this range, the characteristics of the carrier of the present invention are well exhibited, and a sharp image with high image density can be obtained.

Next, a specific example of a developing device that can use the developer of the present invention will be described.

FIG. 1 is a schematic vertical sectional view of the developing device, and FIG. 2 is a schematic sectional view of the developing device shown in FIG.

In the figure, reference numeral 1 denotes a developer container, which is divided into a toner storage section that stores toner and a developer storage section C that stores developer consisting of toner and carrier. The toner in the toner storage section is supplied to the developer storage section C from the toner replenishment port 5 by the rotation of the toner conveyance member 6. The toner in the developer storage section C is used to develop a latent image formed on a photoreceptor (not shown) by a developing sleeve 2, and the developing sleeve 2 includes a magnetic roller 2a fixedly supported at both ends thereof; The sleeve 2b is made of a non-magnetic material and rotates around this in the direction of the arrow at a predetermined circumferential speed.

Further, in the figure, reference numeral 30 denotes a transport pipe installed in the developer container 1, and a screw 3 for transporting the developer in the direction of the arrow is provided inside the transport pipe. 31 is the lower right end (
1) to the right end of the conveying pipe 30,
Inside this is a screw 4 that transports the developer in the direction of the arrow.
is provided, and the developer transported by the screw 4 is transferred from the opening 32 to the transport pipe 30.

A screw 7 is provided at the bottom of the developer container 2 to transport the toner and carrier collected from the surface of the new toner sleeve 2b to the transport pipe 31 while uniformly mixing them.

A toner concentration detection device 20 is installed in the conveyance tube 31, and this toner concentration detection device 20 is installed in a housing B attached to the conveyance tube 31 as shown in FIGS. 3 and 4.
The interior includes a lamp 22 that irradiates light onto the developer in the transport tube 31 through a window 21 formed of a transparent material of the transport tube 31, a first sensor 23 that receives reflected light reflected by the developer, and a lamp. 22, and a second sensor 24 that directly receives the light of 22.

Above 1. The second sensor 23,24 outputs a voltage according to the intensity of the light it receives, and is composed of, for example, a photodiode.When the developer has a predetermined toner concentration, the first sensor 23 The voltage vb that receives and outputs the light reflected by the agent and the second sensor 24 are connected to the lamp 2.
The voltage Vc output by directly receiving the light of 2 is Vb=Vc
It is adjusted in advance so that

Next, the operation of the above-mentioned toner concentration detection device will be explained.

When the developer conveyed through the conveying pipe 31 by the screw 4 has a predetermined toner concentration or higher, the output voltage of the sensor 23.24 becomes Vb>Vc, and at this time, the toner concentration detecting device 20 turns off toner replenishment and maintains the predetermined toner concentration. When the toner concentration is less than or equal to , the output voltage becomes Vb<Vc, and at this time, the toner concentration detection device 20 turns on toner replenishment.

By repeating these operations, the toner concentration of the developer is kept constant.

Note that the present invention is not limited to the above-mentioned developing device configuration and the above-mentioned toner concentration detection device, but can also be applied to a general type of light detection ATR that uses the principle of measuring the reflected light of the developer through a transparent window material in contact with the developer. Applicable to all developing devices.

[Example] The above mixture was melt-kneaded in a two-screw ruder heated to 150°C, cooled, and the cooled material was coarsely pulverized in a mechanical pulverizer to the extent that it could pass through a wire mesh with an opening diameter of inm. It was pulverized to about 10 μm using a jet mill. This finely pulverized product was classified using a wind classifier 100MZR classifier so that the volume average particle size was 11 to 13H. To this, 1.0% by weight of positively charged silica was added to the classified product,
The mixture was mixed using a Henschel mixer to obtain a toner.

acetone:methyl ethyl ketone (1:l) mixed solvent 5
00n+i' to prepare a coating solution, and 1 kg of ferrite particles (Cu-Zn ferrite surface coated with ZnO) having an average particle size of 60 mm were coated with this coating solution using a fluidizing bed device. After removing the solvent, it was dried at 90° C. for 1 hour, and a coated carrier was obtained through a post-process.

8 parts by weight of the toner and the fluororesin-coated carrier 1
00 parts by weight were mixed to prepare a developer.

This developer was applied to a color developing device of a copying machine NP-4835 (manufactured by Canon) having a light detection ATR.

10,000 sheets were continuously copied in a low humidity environment of 15°C and loRH%, but the toner density of the developer was controlled without changing from the beginning to the end, and the reflected image density was around 1.3 without fog. Good quality images were obtained throughout.

A developer was obtained in the same manner as in Example 1, except that Comparative Example C.1 and Pigment Yellow 81 were not used, and images were produced in the same manner as in Example 1.

Initially, the reflected image density was 1.30, but because toner adhered to the sensor window and the ATR malfunctioned, the image density gradually decreased after 8,000 copies, and the image density after 10,000 copies was has fallen to 1.20.

A lake-based azo pigment (C, 1
A developer was obtained in the same manner as in Example 1, except that Pigment Red 4g-1) was used, and images were formed in the same manner as in Example 1.

Initially, the reflected image density was 1.30, but because toner adhered to the sensor window and the ATR malfunctioned, the image density gradually decreased after 5,000 copies, and the image density decreased to 1.30.
It went down to 10.

L school plate C, 1, Pigment Yellow 81 instead of C, I.

Except for using Pigment Yellow 10,
A developer was obtained in the same manner as in Example 1, and an image was formed in the same manner as in Example 1.

Initially, the reflected image density was 1.30, but because toner adhered to the sensor window and the ATR malfunctioned, the image density gradually decreased after 8,000 copies, and the image density decreased to 1.30.
It dropped to 20.

Kentodate 1 Non-lake type insoluble azo pigments C, T, Pigment R
In place of 1 g of ed, non-lake type insoluble azo pigment C,
I.

A developer was obtained in the same manner as in Example 1, except that Pigment Red 1 and 2 were used, and images were formed in the same manner as in Example 1.

Good results similar to those in Example 1 were obtained.

[Effects of the Invention] According to the present invention, it is possible to prevent toner from adhering to the sensor window and malfunction of the ATR, and therefore it is suitable for a developing device having an ATR device.

[Brief explanation of drawings]

Fig. 1 is a schematic longitudinal sectional view of the developing device, Fig. 2 is a schematic sectional view of the developing device shown in Fig. 1, Figs. 3 and 4 are explanatory diagrams of the toner concentration detection device, and Fig. 5 is a photodetection device. FIG. 3 is a diagram illustrating an example of a toner concentration detection section of the ATR method.

Claims (1)

[Claims] Used in a developing device having a photo-sensing automatic toner density control device, at least a non-lake-based insoluble azo pigment and a C.I. I
．． A developer containing a non-magnetic toner containing Pigment Yellow 81 and a binder resin, and a carrier formed by coating magnetic particles with the resin.