JP3434542B2 - Friction charging member for electrostatic image development - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic method and an electrostatic printing method.
Friction belt for electrostatic image developing toner
A triboelectric charging member having a function of applying electric charge.
Carrier or toner that gives a triboelectric charge to the toner.
Transfer restricting members such as
The present invention relates to another frictional charging member for negative charging. [0002] 2. Description of the Related Art Conventionally, Japanese Unexamined Patent Publication No.
Develop electrostatic image with toner as disclosed
The method is roughly divided, and the toner and carrier are mixed
Using a so-called two-component developer and a carrier
One-component developer used alone with toner without being mixed
Is used. The above method uses a toner and a carrier.
A.
To the opposite polarity by this charged toner.
The electrostatic charge image is visualized, and the toner and key
Magnets using iron powder carriers depending on the type of carrier
Brush method, cascade method using bead carrier,
-There is a brush method. In the latter one-component developing method, toner particles are
Powder cloud method used in spray state, toner particles
Contact development method in which the toner is brought into direct contact with the electrostatic latent image surface and developed
(Also called touch-down development), magnetic conductive toner
There is an induction development method of contacting the electrostatic latent image surface. these
As a toner applied to various development methods of
A carbon bra is added to the binder resin made of grease or synthetic resin.
Fine powder in which a colorant such as a paint is dispersed is used.
For example, a colorant is dispersed in a binder resin such as polystyrene.
The particles obtained by finely pulverizing the powder to about 1 to 30 μm
Used as In addition, these components
Those containing magnetic materials such as magnetite are magnetic
Used as a knives. [0004] As described above, it is used in various developing methods.
Toner is correct depending on the polarity of the electrostatic charge image to be developed.
Or negative charge, but retains the charge on the toner.
To do this, the friction band of the resin
Although electrical conductivity can be used, this method
Due to the low chargeability, images obtained by development
Easy and unclear. Therefore, the desired frictional charging
Dye for imparting chargeability, in order to impart the property to the toner,
Pigments or charge control agents can be added.
Has been done. However, these toners
Dye or pigment or charge control agent
Therefore, it must be exposed to the toner surface to some extent. So
Toner friction, collision with carrier, electrostatic latent
Due to friction with the image carrier,
Additives fall off, contamination of carrier, etc., electrostatic latent image holder, example
For example, contamination of the photoreceptor belt or drum occurs.
As a result, the chargeability deteriorates and the number of copies increases.
Eventually, deterioration progresses, image density decreases, fine line reproducibility,
Fogging and the like become a practical problem. Therefore, the toner is provided with a binder resin and chargeability.
Affinity and dispersibility with dyes and pigments or charge control agents
To improve the above problems.
ing. For example, use these additives to increase affinity
There is a method of surface treatment.
In many cases. To improve dispersibility,
There is also a method of increasing the mechanical shear force and dispersing finely
However, the ratio of additives that appear on the toner surface decreases,
It tends not to be given sufficiently. From these facts,
Very limited additives for imparting sufficient charge
There are only a few that have been put into practical use. In addition, not only black and white images but also color images can be obtained.
To be added to the toner is colorless
Is preferred, but conventionally used dyes, pigments or
Many of the charge control agents are dark,
At present, there is almost no research, and intensive research continues.
Have been killed. Therefore, charging is performed with the toner additive.
Instead of carriers, sleeves and doctor blades
Which transport regulating member or other triboelectric charging section
It has been proposed to do with wood. Here, the triboelectric charging member is in contact with the toner.
Touch to provide the necessary charge for development or to supplement
Means a member that can be added to
It is referred to as an abrasion charging member. As described above, the electrostatic latent image
In various electrophotographic methods to visualize,
Proper charging of the toner is a key to obtaining good quality images.
Is important for Here, “appropriate” means that the charge amount
That is, the distribution is narrow and the film is appropriately charged. Therefore, as a member for negatively charging the toner,
Liamide 12 (nylon 12) was considered. Examples and
The development sleeve is made of amorphous polyamide resin and crystalline
Products made of a mixed material of polyamide resin (Japanese Unexamined Patent Publication No.
247478). However, the polyamide 12
Then, the negative charge imparting property is too strong, and
Could not be given. [0009] SUMMARY OF THE INVENTION The present invention overcomes the disadvantages of the prior art.
Overcoming frictional charging to give the toner an appropriate negative charging property
The purpose is to provide a member, and yet another object is low water absorption
To provide a stable negative charge to the toner.
And a friction band suitable for charging vivid color toner
Even after providing a charging member and continuous copying,
Provide a triboelectric charging member that gives the same image quality as an image
It is to try. [0010] Means for Solving the Problems The present inventors have made intensive studies.
As a result of stacking,Less surface in contact with electrophotographic toner
Polyamide and Polytetra as negative charge control agents
Block copolymers copolymerized with methylene oxideYes
That the above object can be achieved by the triboelectric charging member
Was found. Polyamide and poly used in the present invention
Block copolymer obtained by copolymerizing tetramethylene oxide
Is represented by the following general formula.     [-CO- (PA)_l-COO- (PTMO)_m-O-]_n Here, PA is a polyamide component, and PTMO is
It is a tramethylene oxide component. The above polyamide and tetramethylene oxide
The block copolymer obtained by copolymerizing is synthesized by a known method.
You. For example, a polyamide synthesized in advance and a
Condensate the literamethylene oxide. Pre-combined
Polyamide and polytetramethylene oxide
Coupling in the presence of a coupling agent. A pre-synthesized port
Litetramethylene oxide as polyhydric alcohol component
To be polycondensed with a polyvalent amino acid. A pre-synthesized port
In the presence of literamethylene oxide, caprolactam or
The ω-amino acid is subjected to ring-opening polymerization. And so on. The block copolymer used in the present invention has a
The tetramethylene oxide component is tetramethylene oxide.
Ring-opening polymerization of sides, which is carried out in the presence of a catalyst
It is performed under or in the presence of active hydrogen. Range of its degree of polymerization
Is about 500 to 1000. Also used in the present invention
The polyamide component of the block copolymer is
Polycondensation of basic acids and polycondensation of ω-amino acids
Of the ring-opening polymerization of caprolactam
Called nylon mn or nylon n (m and n are integers)
Is what it is. A specific example is nylon 6 (ε-cap
Lactam ring-opening polymer), nylon 66 (hexamethyl
Condensed polymer of diamine and adipic acid), nylon 61
0 (condensation polymerization of hexamethylenediamine and sebacic acid
Body), nylon 11 (condensation polymerization of ω-aminoundecanoic acid)
Body), nylon 12 (ring-opening polymerization of ω-laurolactam)
And their copolymers. The degree of polymerization is
It is about 500-1000. The block ratio l / m is 0.
5-3.0 is preferred. [0013] The present invention is used as a charge control agent
Said block copolymer, as it is in a solvent or dispersion medium
It may be used by being dispersed, or it may be used by being dispersed in a resin.
Good. As such a resin, a general resin can be used.
They are, for example, polystyrene, polyacrylate
Ter, polymethacrylate, polyacrylonitrile
Rubber-based trees such as polyisoprene and polybutadiene
Fat, polyethylene, polypropylene, polyester, polyester
Polyurethane, polyamide, epoxy resin, polycarbonate
Sheet, rosin, phenolic resin, chlorinated paraffin,
Silicone resin, fluororesin and their derivatives, or
Are these copolymers, and mixtures thereof. The above coating liquid is applied to the base material of the triboelectric charging member.
Apply by tapping, spraying, brush coating, etc., and dry
Then, the triboelectric charging member of the present invention is obtained. Ma
In addition, a resin in which the above compound is dispersed is directly molded and rubbed.
It may be a triboelectric charging member. In this case, reinforcement,
Silica, carbon, carb
Fiber, glass fiber, etc.
No. As a base material of the carrier-type triboelectric charging member,
All known carriers are available, iron, nickel
Metals or alloys such as aluminum and aluminum, metal oxides, etc.
Metal compound particles, glass, silicon carbide, etc.
Which ceramic particles are used. Further sleeves and do
As the base material of the triboelectric charging member in the form of a collector blade
Is a metal or alloy such as iron, aluminum, stainless steel, etc.
Non-metallic compounds such as gold, plastic, rubber, etc.
The used sleeve and doctor blade can be used.
You. According to the present invention, as a result of repeating various experiments,
Polyamide and tetramethylene oxide for triboelectric member
By using a block copolymer obtained by copolymerizing
Good negative charge and good copy
It is based on knowledge. Applying triboelectric charging as described above
The following are examples of charge-imparting agents that are supplementarily added to members.
There are things. For example, metal complexes of monoazo dyes, nitro
Lofamic acid and its salts, salicylic acid, naphthoic acid, dika
Metal complexes of rubonic acid such as Co, Cr and Fe, sulfonation
Introduced copper phthalocyanine pigment, nitro group and halogen
Styrene oligomer, chlorinated paraffin, melamine
There are resins and the like. The frictional charging member of the present invention as described above and
The toner used in combination is the conventional electrophotographic toner.
What is used as a toner can be used. That is,
The knurl may be magnetic or non-magnetic. For more information
The toner is a colored fine particle containing a colorant in a binder resin.
Alternatively, a magnetic powder may be contained as necessary. Again
These toners provide more efficient charging
A small amount of a charge imparting agent, such as a dye or pigment, a charge control agent, etc.
May be contained, but may be considerably less than before. band
Examples of the charge imparting agent include nigrosine and C2 to C16.
Azine dyes containing an alkyl group of the formula (JP-B-42-162)
7), basic dyes, lake pigments of basic dyes, C.I. I.
Solvent Black 3, Hansa Yellow G, C.I. I. Mo
Ruderant Black 11, C.I. I. Pigment Black
1. Gilsonite, asphalt, quaternary ammonium
Salt, metal salt of higher fatty acid, metal complex of acetylacetone
Body, vinyl polymer containing amino group, amino group
Polyamine resins such as condensed polymers to be contained. [0017] If necessary, such as colloidal silica
Fluidizers, metallic acids such as titanium oxide and aluminum oxide
Abrasives such as silicon carbide and silicon carbide, and fatty acid metal salts.
And the like. Below, non-magnetic one-component developing equipment
The invention will be described by taking an example as an example. Magnetic one-component, two-component, etc.
However, it is clear that a similar material configuration is possible. In the apparatus as shown in FIG.
70, a supply roller 40, a developing roller 20, and
The blade 30 is arranged as shown. The toner is
Leasing, supply roller, developing roller and blade
Is rubbed and charged. Of these, the developing roller is supplied
Rub the toner at two points between the roller and the blade.
Since it is frictionally charged, it is the most dominant
You. [0019] The present invention will be further described below with reference to the following examples.
Although explained concretely, the present invention is not limited to this.
Absent. Example 1 Block copolymer of polyamide and polytetramethylene oxide
A typical polymer is one having the following structural formula
Was used. [-CO- (NH- (CH_Two)₁₁-CO)_l-C
OO-(-(CH_Two)_Four-O-)_m-O-]_n This is a block of nylon 12 and polytetramethylene oxide.
It is a lock copolymer. 1 / m = 0.5,1.0,1.
5, 2.0, 3.0 and 5 types with different composition ratios
Nylon 12 was used for the
Presented with a 100μm thickness fused to an aluminum core
An image roller was used. [0021] Toner: A (Styrene acrylic binder), B (Binder
Is polyester), C (polyol is binder) Blade: polyurethane Supply roller: conductive polyurethane sponge Casing: ABS resin Measurement environment: 20 ° C, 65% RH FIG. 2 shows the results of toner charging in the examples. Fig. 2
Compared with the case of using the Ron 12 alone.
When using a block copolymer, the toner is appropriately negatively charged.
It indicates that Also, using these developing devices
When the image evaluation was performed at the same time, the toner charge amount was -7.
When it is smaller than μc / g (absolute value), fog appears on the image.
Occurred. The toner charge amount is -30μgreater than c / g
(Absolute value)
Was seen. In addition, l / m = 2.0 and 3.0
About 10 ℃ 20% RH and low temperature and 30 ℃
The experiment was conducted under the high temperature and high humidity environment of 90% RH.
The fluctuation of the charge amount is within 20%, which is equivalent to that at normal temperature and normal humidity.
Images were obtained and no abnormal images were seen. In this embodiment, the block copolymer resin
Was used as a dielectric layer, but it was guided by additives such as carbon.
It may be electrically conductive, or combined with other components to form a composite surface
Even in this case, the charge imparting property can be handled by selecting the composition ratio. Further
In this example, the block copolymer resin was developed.
This resin was used as a roller.
Therefore, it can also be used as elastic rollers, belts and blades
Noh. [0023] As described above, in the present invention,
Polyamide and polytetramethylene oxide copolymerized
Using block copolymer resin as a triboelectric charging member
Therefore, by selecting the composition ratio, regardless of the toner,
Appropriate toner charging can be obtained. In addition, low water absorption
As a result, it is possible to obtain a toner charge amount with little
You.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view for explaining an example of an electrostatic charge developing device provided with a frictional charging member of the present invention. FIG. 2 shows the results of Examples of the present invention and Comparative Examples. DESCRIPTION OF SYMBOLS 10 Electrostatic latent image carrier 20 Developing roller 30 Blade 40 Toner supply roller 50 Agitator 60 Toner 70 Casing 80 Development area

Claims (1)

(57) [Claims] [Claim 1] The surface in contact with the toner for electrophotography is small.
Polyamide and polytet as at least negative charge control agents
A triboelectric charging member comprising a block copolymer obtained by copolymerizing ramethylene oxide .