JPS63256965A - Toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To prevent generation of damaging and fusing of a photosensitive body by making combination use of two kinds of toners which are different in gel component. CONSTITUTION:This toner is obtd. by mixing a 1st magnetic toner A having 5-40wt.% gel component of the toner and a 2nd magnetic toner B having 20-60wt.% gel component of the toner with the gel component of the toner A< the gel component of the toner B. Offset is liable to arise in a fixing stage if the gel component of the toner A is <=5wt.% and fixability is poor if said component is >=40wt.%. Fusing is liable to arise on the surface of the photosensitive body if the gel component of the toner B is <=20wt.% and the photosensitive body is liable to be flawed by the hardness of the toner if the gel component of the toner B is >=60wt.%. Namely, the intrinsic function of the toner and the function to maintain the life of the photosensitive body are separated by mixing the toner A and the toner B. A long life is thereby provided to the photosensitive body without generating the flawing, fusing, etc., in the photosensitive body.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a toner used in electrophotography, electrostatic printing, magnetic recording, and the like.

[Prior Art] Conventionally, as an electrophotographic method, US Pat.
A number of methods are known, such as those disclosed in Japanese Patent Publication No. 43-24748, etc., but in general, an electrical latent image is formed on a photoreceptor by various means using a photoconductive substance. Next, the latent image is developed using toner, and if necessary, the toner image is transferred to a transfer material such as paper, and then fixed by heat, pressure, solvent vapor, or the like to obtain a copy. Furthermore, when a toner image transfer process is included, a cleaning process for removing residual toner is usually provided.

The remaining toner on the photoreceptor is generally removed by bringing a cleaning member into contact with the photoreceptor, such as a blade cleaning method, a fur brush cleaning method, or a magnetic brush cleaning method. In this case, since the cleaning member is in contact with the photoreceptor with an appropriate pressure, the photoreceptor may be scratched or the toner may be fused during repeated use. In order to avoid this phenomenon in which the toner fuses to the photoreceptor, Japanese Patent Laid-Open No. 48-47
No. 345, it is proposed to add both friction-reducing materials and abrasive materials to the toner.

However, if a friction-reducing substance is added to an extent that can avoid the toner fusion phenomenon, it becomes difficult to remove low electrical resistance substances such as paper dust and ozone adducts that form or adhere to the surface of the photoreceptor due to repeated use. Especially in high temperature and high humidity environments, the latent image on the photoreceptor is significantly damaged by low electrical resistance materials. Furthermore, the amounts of the friction-reducing substance and the abrasive substance to be added are delicate, making it difficult to obtain a toner with stable characteristics.

Incidentally, in recent years, copying machines have become faster and more diverse in their functions, and some copying machines have appeared that have the ability to perform multiplex and multicolor copying with a single touch.

Furthermore, copying machine bodies have become smaller and simpler, and many new problems have arisen that were previously unthinkable.

Furthermore, in recent years, OPc has been widely used as a photoreceptor, but as the speed increases, it is desired to have even higher durability. To this end, the OPC photoreceptor itself is being improved, but the cleaning process of scraping off the residual toner after transfer has a significant impact on the life of the photoreceptor. In this case, the remaining toner to be cleaned adheres to the cleaning device (cleaning blade, cleaning roller) and acts as a lubricant and abrasive.

That is, the toner needs to have the effect of preventing scratches, fusion, and filming on the photoreceptor.

Conventionally, PVDF, Zn5 were used to extend the life of the photoreceptor.
Inorganic fine particles such as lubricants such as T or abrasives such as silica and strontium titanate are used.
None of these methods is sufficient to prevent scratches, fusion, filming, image deletion, etc., and may actually have the opposite effect from the viewpoint of high speed and high durability. Furthermore, if the amount of charge, particle size, amount of magnetic material, gel content, molecular weight distribution, etc. are controlled in order to make the toner itself suitable for cleaning, various problems will occur in processes other than cleaning. For example, the amount of charge, particle size, and amount of magnetic material affect development and transfer, and the gel content, molecular weight distribution, etc. greatly affect fixing and offset properties.

In addition, when small-sized paper is continuously passed, there is a difference in the amount of abrasion due to the abrasive force of the toner between the non-paper passing area and the paper passing area of the drum, resulting in uneven halftone density, filming, etc.
This can cause serious problems such as scratches.

As mentioned above, toners are required to have a wide variety of properties and properties.

[Problems to be Solved by the Invention] The first object of the present invention is to provide a toner that can provide a long service life without causing scratches, fusion, filming, image deletion, etc. on the photoreceptor even in high-speed copying machines. It is in.

A second object of the present invention is to provide a toner that can provide clear copied images without fluctuations in image density or fog even after repeated use.

A third object of the present invention is to provide a toner that does not cause blocking even when a temperature rise occurs in a high-speed, small-sized copying machine and can provide stable, high-quality copied images.

A fourth object of the present invention is to create a toner that is suitable for constant wear on the heated roller, that is, it can be sufficiently fixed with a relatively low capacity heat source, has almost no offset of the toner to the heated roller, and can be easily ejected from the roller. The aim is to provide an excellent toner with uniform properties that can be applied smoothly.

[Means and effects for solving the problems] The present invention combines the original function of the toner and the function of maintaining the life of the photoreceptor with the toner A.
Functional separation is achieved by mixing toner B and toner B.

Toner A and toner B are charged to opposite polarities in a developing device due to interparticle friction, and toner A is developed on the image area on the photoreceptor, and a copied image is formed through the steps of transfer, separation, and fixing. Further, toner B is developed on the non-image area and non-paper passing area on the photoconductor, and since the transfer efficiency is toner A>) toner B, much of the toner B is not transferred and is cleaned in the cleaning process. Therefore, even when small-sized paper is continuously passed, the drum can be polished uniformly and its magnetic properties can be maintained.

The toner of the present invention includes a first magnetic toner A in which the gel content of the toner is 5 to 40% by weight, preferably 5 to 30% by weight of the toner weight, and a first magnetic toner A in which the gel content of the toner is 20 to 60% by weight of the toner weight. It is obtained by mixing a second magnetic toner B in an amount by weight, preferably 25 to 50% by weight, and the gel content of toner A is the gel content of toner B. When the gel content of toner A is less than 5% by weight, offset tends to occur in the fixing process, and when it is more than 40% by weight, fixing performance deteriorates. Further, if the gel content of toner B is less than 20% by weight, fusion will easily occur on the surface of the photoreceptor, and if it is more than 60%, the photoreceptor will be easily damaged due to its hardness.

In addition, the peak value of the GPC curve obtained from the gel permeation chromatography (hereinafter abbreviated as GPC) chart after the gel content of toner A was removed was 5,000 to 2.
0,000, preferably e,ooo to 17,000, and the peak value of toner B is 10,000 to 30,000.
, preferably 12,000 to 25,000, which is the peak value of toner A minus the peak value of toner B. Toner A
If the peak value is less than 5,000, offset tends to occur in the fixing process, and if it is more than 20,000, the fixing performance becomes poor. Further, when the peak value of toner B is 10,000 or less, fusion tends to occur on the surface of the photoreceptor, and when it is 30,000 or more, the photoreceptor is likely to be damaged.

The mixing ratio of toner A and toner B is A:B=1.000
: 1-10: 1, preferably 500: 1-20
:1 is preferable.

If the content ratio of toner B is less than 1.000:1, the effect on photoreceptor maintenance will be small, and if it is more than 10:1, there will be too much toner in the non-image area, leading to an increase in toner consumption.

Further, the amount of magnetic material contained in toner A is preferably 25 to 50% by weight with respect to the weight of toner A, and the amount of magnetic material contained in toner B is preferably 20 to 40% by weight with respect to the weight of toner B. Further, it is preferable that the amount of magnetic material in toner A is greater than the amount of magnetic material in toner B.

It is necessary to prevent toner B from accumulating in the developing device and maintain the initial image quality even after a large number of sheets are used.

The particle size of toner A and toner B is 5p to 20IL on average by volume.
Preferably, those having substantially the same particle size distribution are used.

The gel content of the toner in the present invention is measured as follows.

First, approximately 1 g of toner is weighed, placed in a Soxhlet extraction filter paper, and weighed accurately. Also, put chloroform 15hj+ into a Soxhlet flask, set the equipment, and perform extraction for 6 hours in an oil bath kept at 100°C (at this time, asbestos tape is wrapped around the Soxhlet extractor to keep it warm).

After that, the chloroform solution containing the dissolved resin was taken out of the Soxhlet flask, transferred to an eggplant flask (AG) that had been accurately weighed in advance, and the chloroform was separated using an evaporator.
After sufficiently drying at ~80°C, return to room temperature and accurately weigh (bg). Furthermore, since the toner contains a large amount of inorganic components such as magnetic materials, the weight is subtracted and calculated using the following formula.

Gel content (weight %) = The main peak value of the molecular weight by GPC in the present invention is measured under the following conditions.

That is, the column was stabilized in a heat chamber at 40°C, and THF (
Tetrahydrofuran) per minute/III! flow at a flow rate of
A THF sample solution of the resin adjusted to a sample concentration of 0.05 to 0.1% by weight is injected at 50 to 200 liters and measured.

In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithm value and the count number of a calibration curve prepared using several types of monodisperse polystyrene standard samples. The standard O polystyrene sample for creating a calibration curve is, for example, a polystyrene sample manufactured by Pressure Chemical or Toyo Tsudani Gyogyo with a molecular weight of 6 x 1.
02.2. IX 103,4 X 103.1.75
X 104°5, I X 104. 1. IX 105
．． 3.9X 105.8.6X 105゜2 X 10
6.4.48 x 106, at least 1
It is appropriate to use a standard polystyrene sample with a score of about 0. Further, an R2 (refractive index) detector is used as a detector.

In addition, in order to accurately measure the molecular weight range of 103 to 2X106, it is recommended to use a combination of multiple commercially available polystyrene gel columns, such as g-styragel 500.10'' manufactured by Waters.

104.105 combination and 5hodex manufactured by Showa Denko ■
A-8 (IM and 5hodex A-802, 803,
Combination of 804 and 805, TSKge manufactured by Toyo Soda■
l G 2500H, G30001 (, G4 (100N
.

05000)1. A combination of G6000H and G30001 is desirable.

Furthermore, the binder used in the present invention has the following composition.

For example, monopolymers of styrene and its substituted products such as polystyrene, poly p-chlorostyrene, and polyvinyltoluene; styrene-p-chlorostyrene copolymers, styrene-propylene copolymers, styrene-hinyltoluene copolymers, Styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-acrylic ethyl copolymer, styrene-butyl acrylate copolymer,
Styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methyl methacrylate copolymer, styrene-acrylic-aminoacrylic copolymer, styrene-amino Acrylic copolymer, styrene-α-methyl chloromethacrylate copolymer, styrene-acrylonitrile [f polymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer Styrenic copolymers such as styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, and styrene-maleic acid ester copolymer; Methyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyacrylic resin, rosin, modified rosin, terpene resin, phenolic resin, aliphatic or Alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes, etc. can be used alone or in combination.

Further, during the polymerization of these binders, the following crosslinkable polymers may be present for the purpose of controlling the molecular weight.

Divinylbenzene, divinylnaphthalene, divinyl ether, divinyl sulfone, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butylene glycol diacrylate methacrylate, 1.
6-hexane gelicol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2.2'-bis(4-methacryloxyjethoxyphenyl)propane, 2.2'-bis(4 -acryloxyjethoxyphenyl)propane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, dibromneopentyl glycol dimethacrylate, allyl phthalate, 1,2-propylene glycol, 1,3- Common crosslinking agents such as butanediol can be used as appropriate.

Any suitable pigment or dye can be used as a colorant in the toner of the present invention. For example, carbon black,
Known pigments and dyes include iron black, phthalocyanine blue, ultramarine blue, quinacridone, and benzidine yellow.

Furthermore, the toner of the present invention may also contain iron, such as ferromagnetic elements and alloys and compounds containing them, such as magnetite, hematite, and ferrite.
It may also contain magnetic powders conventionally known as magnetic materials, such as alloys and compounds of cobalt, nickel, and manganese, and other ferromagnetic alloys. Furthermore, carbon black, nigrosine, metal complex salts, colloidal silica powder, fluororesin powder, etc. may be added for the purpose of charge control, prevention of aggregation, etc.

The surface hardness of the photoreceptor used in the present invention is preferably 5 g or more, preferably 8 to 20 g, as measured by the method shown below. If the hardness is low, the photoreceptor is easily scratched, and the scratches may cause disturbances in latent images in high humidity or generate toner that is not cleaned.

Furthermore, if the hardness is too high, it becomes impossible to remove the low-resistance material formed on the surface of the photosensitive plate, resulting in disturbance of the latent image at high humidity.

Hereinafter, a case where an OPC photoreceptor is measured will be described as an example of hardness measurement.

The OPC photoreceptor was fixed on the sample stage of HEIDON 14 type surface property measuring machine (manufactured by Manabu Shinkimura), and the OPC photoreceptor was attached to a diamond needle (conical, with a cone angle of 90°. However, the tip had a diameter of 0. , a hemispherical shape of 01mm), a vertical load of Xg is applied to the sample stage, and
Move at a speed of 1 inch to scratch the surface of the OPC photoreceptor.

The depth of this scratch is measured using, for example, a surface roughness meter.

Perform the above operation with the load Xg being 10g or 15g, for example.

20g, 25g, 30g, 35g, 40g,・
. . . The load that causes a scratch at the depth of Igm is calculated from the linear regression relationship between the depth of the scratch and the load, and is taken as the hardness of the OPC photoreceptor. If the OPC photoreceptor is a drum, it is necessary to set the OPC photoreceptor on the sample so that scratches can be made in the axial direction of the drum.

An example is shown in FIGS. 1 and 2.

In the figure, numeral 1 indicates a photoreceptor, and this photoreceptor is designed to be rotated in the direction indicated by an arrow in the figure. During operation of the apparatus, an electrostatic latent image is formed on the photoreceptor 1 by a well-known method, the latent image is visualized by using toner, and this visible image is transferred to a transfer material. A cleaning device is provided to remove toner 6 remaining on photoreceptor 1 after transfer.

The cleaning device shown in FIG. 1 includes a cleaning member 2 for scraping off toner 6 on the photoreceptor 1, and a collection member 5 for collecting the toner detached from the photoreceptor 1 by the cleaning member 2. Generally, the collecting member 5 is a photoreceptor l.
The cleaning member 2 prevents the toner scraped off by the cleaning member 2 from scattering outside the cleaning device.

The cleaning device shown in FIG. 2 includes a cleaning roller 3 that scrapes off the toner 6 on the photoreceptor 1 and a cleaning member 2 that scrapes off the toner 7 that cannot be removed by the cleaning roller. The toner scraped off by the member 2 falls onto the cleaning roller 3, and the toner scraped off by the cleaning roller falls onto the scraper 4.
recovered in the cleaner.

The cleaning member 2 is made of J15-A, such as urethane rubber.
An elastic rubber blade having a hardness of 60 DEG to 80" is preferable, and can be brought into contact with the photoreceptor 1 at different angles. At this time, a linear pressure of 5 to 20 g/cm is ideal for the contact pressure.

The developer of the present invention can be applied to various developing methods. For example, a magnetic brush development method, a cascade development method, a method using a conductive magnetic toner described in U.S. Pat. A method using
Examples include methods described in Japanese Patent Nos. 4-42141, 55-18656, and 54-43027, fur brush development methods, powder cloud methods, and impression development methods.

Further, as the cleaning method used in the present invention, a blade cleaning method, a fur brush cleaning method, a magnetic brush cleaning method, etc. are used.

Immediately before the cleaning process, a static elimination process or the like may be provided, if necessary, to facilitate toner cleaning.

[Example] After thoroughly mixing the materials shown in Table 1 with a blender, the temperature was 150°C.
The mixture was kneaded using two heated rolls. After allowing the kneaded mixture to cool naturally, it is coarsely pulverized using a cutter mill, then further pulverized using a pulverizer using a jet stream, and classified using an air classifier to obtain a fine powder with a volume average particle diameter of 1271 m. I got ■. Using this fine powder ■～0, prepare toner as shown in Table 2,
Examples 1 to 9 and Comparative Examples 1 to 6 were conducted.

Example 1 100 parts by weight of fine powder and 0.5 parts by weight of silica treated with silicone oil modified with an amine group were mixed in a sample mill to obtain toner A, and 4 parts by weight of fine powder (1) was added to 00 parts by weight of toner Al as toner B. A toner was prepared by mixing parts by weight. When this toner was subjected to a durability test using a modified Canon NP-3525 machine, the density was as high as 1.30 from the beginning, and the image quality did not deteriorate even after a durability test of 50,000 sheets.

The modified NP-3525 machine is equipped with a cleaning device of the type shown in Figure 2, but the blade contact pressure is 8 g/c.
When we conducted a durability test using an OPC drum with a photoreceptor hardness of 10 g, the amount of drum wear was 3.5 after 50,000 sheets.
grn, there were almost no drum scratches, no filming occurred, and the image quality was not affected at all.

Example 2 When Example 1 was carried out in the same manner as in Example 1 except that the type of cleaner shown in Fig. 1 was used, the amount of drum abrasion was 2.2 mm after 50,000 sheets were printed.
Similar good results were obtained, except that 5 p and m were obtained.

Examples 3 to 7 The same procedure as in Example 1 was carried out except that the type of fine powder to be mixed and the mixing ratio of toner were changed.

The results are shown in Table 2.

Example 8 100 parts by weight of fine powder [phase] as toner A was mixed with 0.5 parts by weight of silica treated with hexamethylene disilazane in a sample mill, and 4 parts by weight of fine powder 0 was added as toner B to 100 parts by weight of this toner. The mixture was mixed to obtain a toner.

OPC this toner to Canon NP-3525 modified machine.
A drum was used to perform image development and durability as reversal development. The image density was sufficiently high at 1.33 compared to the initial state, and the drum abrasion after 50,000 sheets was as low as 3.0 gm, with almost no scratches, no filming, and no deterioration in image quality.

Comparative Examples 1 to 4 Comparative Examples 1 to 4 were carried out in the same manner as in Example 1 except that the type of fine powder to be mixed and the mixing ratio were changed. However, the treated silica used in Example 8 was used.

The results are shown in Table 2.

Example 9. Comparative Example 5 The same procedure as in Example 7 was carried out except that the type of fine powder to be mixed and the mixing ratio were changed. However, the treated silica used in Example 8 was used.

The results are shown in Table 2.

Comparative Example 6 The same procedure as in Example 1 was carried out except that Toner B was not used and Toner A was used as the only toner.

As a result of a durability test of 50,000 sheets, the drum wear was 2.5.
Although the number was small (1L+1), there were many scratches, and especially when passing small-sized paper, the drum abrasion in the non-paper passing area was as small as 17zm, and the key was seen even in normal images.

[Effect of the invention J] By using two types of toner with different gel content, various problems such as scratches, fusion, and filming on the photoreceptor can be solved,
Moreover, it has become possible to obtain stable, high-quality copied images.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a cleaning device for a photoreceptor inside a copying machine, and FIG. 2 is an explanatory diagram of a cleaning device of a different type from that shown in FIG.

Claims (1)

[Scope of Claims] 1) A first magnetic toner A having a toner gel content of 5 to 40% by weight and a second magnetic toner B having a toner gel content of 20 to 60% by weight are mixed. obtained, the gel content of A<B
A toner for developing an electrostatic image, characterized by having a gel component. 2) The peak value of the GPC curve obtained from the gel permeation chromatography (hereinafter abbreviated as GPC) measurement chart after removing the gel component of Toner A is 5,000 or more.
20,000, and the peak value of toner B is 10,00
0 to 30,000, and the peak value of toner A is less than the peak value of toner B.