JP2000347446A - Toner and developing device - Google Patents

Abstract

(57) [Summary] [Problem] To blur printing part due to deterioration of charging characteristics of toner, agglomeration due to lowering of fluidity of toner, occurrence of stains due to the aggregation, and fine print collapse due to abnormal rise in toner potential. And unevenness in print density are eliminated, and a clear image is formed. SOLUTION: A toner supply roller 4 has an elastic layer having an Asker F hardness of 40 ° to 60 °, and a compression deformation amount at a contact portion between a developing roller 2 and the toner supply roller 4 is 0.5 m.
m to 2.0 mm. The elastic layer of the toner supply roller 4 is formed of closed cells and has a cell diameter of 0.15 mm to 0.4 m.
m is preferred.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner and a developing device in an electrophotographic printer used in a printer, a facsimile, a copying machine, and the like. More specifically, the present invention relates to a toner and a developing device for visualizing an electrostatic latent image.

[0002]

2. Description of the Related Art In recent years, electrophotographic printers have been widely used for printing output images in printers, facsimile machines, copiers and the like. In such an electrophotographic printer, a developing device using a toner is used in order to reduce the size, weight, and cost of the printer and improve reliability. In addition, in order to colorize an electrophotograph, a developing device using a toner having a high transparency and a non-magnetic one component is considered to be advantageous, and the developing device is expected to be more widely used. I have.

FIG. 2 is a cross-sectional view showing a general configuration of the entire developing device. As shown in FIG. 1, the developing device includes a photosensitive drum 1, a developing roller 2, a toner supply roller 4, and a developing blade 6. Then, the toner 3 is supplied from the toner supply roller 4 to the surface of the developing roller 2 against which the roller 4 is pressed, is thinned by the developing blade 6, and has a predetermined polarity by both rollers 2, 4. After being triboelectrically charged, the electrostatic latent image is electrostatically transferred to the electrostatic latent image formed on the surface of the photosensitive drum in contact with or in proximity to the developing roller, and the electrostatic latent image is visualized.

In this developing apparatus, the toner supply roller 4 is used to supply the toner to the developing roller 2 as described above, and at the same time, frictionally charges the supplied toner and scrapes and collects unused toner. Have been.

If the pressing force of the toner supply roller 4 against the developing roller 2 and the nip of the elastic layer are set to be small, it is considered that the toner supply roller does not sufficiently supply the toner onto the developing roller and scrape unused toner. Become. If the supply of the toner is insufficient, a desired print density cannot be obtained, or the entire print becomes unclear. In addition, when the toner collection is insufficient, especially in low-density printing, the toner remaining on the developing roller is friction-charged many times, so that the toner potential rises abnormally,
Due to the excessive charging, toner adheres more than necessary. As a result, the toner also adheres to the non-printing portion to cause stains, and fine print dots are connected to blur the image. Further, since the occurrence of excessive charging is not uniform, there is a problem that unevenness in print density is apt to occur.

Therefore, in the conventional developing device, the toner supply roller is required to be 70 mm in order to smoothly supply and recover the toner.
It is formed of an elastic layer having a relatively high Asker F hardness of 、 to 80 °, for example, a silicone foam or a urethane foam, and is pressed against a developing roller with a large pressure. The amount (hereinafter referred to as nip) is usually set to a large value of 0.3 mm to 0.5 mm.

[0007]

However, if the hardness and nip of the elastic layer of the toner supply roller are set to be large,
When the toner receives a large pressing force between the elastic layer and the developing roller, the toner particles are gradually deformed and the like, and the charging characteristics of the toner are deteriorated. When the charging characteristic of the toner is deteriorated, the toner may not be electrostatically attached to the photosensitive drum, so that the print density is reduced or so-called blurring occurs.

Further, when a large pressing force is applied to the toner, the fluidizing agent attached to the toner particles to impart fluidity to the toner is buried in the toner particles or separated from the toner particles. . For this reason, there is a problem that the fluidity of the toner is reduced and the supply to the developing roller becomes insufficient, or the toner particles are easily aggregated, so that the supply of the toner is further insufficient.

In order to prevent the deformation of the toner particles, the amount of adhesion of the fluidizing agent is increased, but in this case, the amount of the fluidizing agent separated from the toner particles is increased. And since the separated fluidizing agent adheres to the developing roller, it is not possible to give a sufficient triboelectric charge to the toner,
This causes background fogging. Further, since the fluidizing agent has a large specific surface area, it is easily affected by the surrounding environment, particularly humidity. Therefore, when the amount of the adhering agent is increased, the water content of the toner greatly changes.
The charging characteristics of the toner greatly depend on the surrounding environment, and the printing quality becomes unstable.

[0010]

Means for Solving the Problems As a result of continuing research on toner, the present inventors have obtained the following findings. The toner produced by the conventional pulverization method has irregular toner particles having corner portions and has a plurality of contact points with the roller surface, so that the toner is moved from the surface of the toner supply roller to the roller surface of the developing roller. Requires a lot of energy. In the conventional developing device, the pulverized toner is
Since it is indefinite, it is apt to be deteriorated by receiving a very large pressing force between the developing roller and the toner supply roller, resulting in remarkable deterioration of print quality. Further, inorganic fluidizing agents such as various silicas externally added to the surface of the toner particles are buried or separated on the surface of the toner when subjected to a pressing force, so that the fluidity of the toner is lost. Due to agglomeration, the fluidity is further impaired, and image blurring occurs especially in high duty printing. Conventionally, in order to secure the fluidity of the toner, an excessive amount of an inorganic fluidizing agent has been added to the toner as described above.

However, the excess inorganic fluidizer is particularly likely to peel off from the toner particles having corners, and a part of the peeled inorganic fluidizer adheres (fixes) to the surface of the developing roller, so that the developing roller has sufficient toner. Since it prevents the application of a triboelectric charge, it causes background fog. Also,
Since the inorganic fluidizing agent has a large specific surface area, there is a problem that the moisture content of the toner as a whole changes greatly due to a change in the humidity of the surrounding environment, and the electrophotographic printing becomes unstable.

Accordingly, the present invention provides a toner containing toner particles and a fluidizing agent added to impart fluidity to the toner particles, wherein the toner particles having a curved surface are used. The amount L of toner particles added to the toner particles is represented by n for the type of fluidizing agent and M
(N), when the particle size of the fluidizing agent n alone is K (n),
Set by the following formula. L = 0.007 <Σ (M (n) / K (n)) <0.060

The present inventors have considered that the optimal amount of the fluidizing agent depends on the particle size of the simple substance of the fluidizing agent, and the number of the fluidizing agent affects the fluidity and the separation amount of the toner. . For this purpose, it is necessary to determine the amount of the fluidizing agent to be added based on a value that can be normalized (standardized) by the particle size of the simple substance. That is, the relationship between the particle size and the weight is such that the weight is proportional to the cube of the particle size. For example, when the particle size is doubled, the weight becomes 2 to the third power = 8 times. Therefore, the addition amount of the fluidizing agent can be expressed as follows. Addition parts by weight / (particle size of simple substance) ³

When two or more fluidizers are added, the amount of the fluidizer is represented by 種類 (parts by weight of fluidizer n) / (plasticizer n) Particle size of ³ ). However, it was found that the print quality fluctuated even when the added amount of the fluidizing agent was fixed.

Then, as a result of further intensive studies by the inventors, the following has been found. That is, the simple substance of the fluidizing agent has a particle size of a submicron unit, and the simple substance rarely exists alone. In other words, the simplex exists in an aggregated state. For this reason, even if the addition amount of the fluidizing agent is fixed, it can be estimated that the print quality does not fluctuate and become constant. Therefore, when the type of the fluidizing agent is n, the added weight part thereof is M (n), and the particle size of the simple substance of the fluidizing agent n is K (n), the ratio of the added weight part to the particle size of the simple substance is It can be expressed by the following equation. Σ (M (n) / K (n)) When the addition amount of the fluidizing agent was fixed based on this ratio, printing could be performed with a constant print quality.

Next, assuming that a value obtained by normalizing the added parts by weight of the fluidizing agent based on the particle diameter thereof is an optimum addition amount L of the fluidizing agent to the toner particles, this L is obtained by an experiment. 0.007 <Σ (M (n) / K (n)) <0.060. When the addition amount L is smaller than 0.007,
In addition to the poor flow characteristics of the toner, the deformation of the toner particles on the curved surface occurs frequently.
In addition, it is easily affected by humidity.

In the present invention, the fluidizing agent can be used without particular limitation as long as it is conventionally used for toner. Examples of preferred inorganic fluidizers include silica, titanium oxide, and alumina. The fluidizing agents can be used alone or in combination of two or more.
The average particle size of the aggregate of the inorganic fluidizer is 1 nm to 1,000 nm.
And preferably 5 nm to 500 nm. When the particle size is limited to less than 1 nm, the particle diameter is easily fixed to the developing roller or the photosensitive drum, and
If it is larger than 0 nm, the fluidity of the toner is reduced.

Further, in the present invention, together with the inorganic fluidizing agent,
Abrasives can be added. The abrasive is added for preventing the fluidizing agent from adhering to the developing toner and for removing the adhered fluidizing agent, and may be used without particular limitation as long as it is conventionally used for toner. it can. Examples of preferred organic abrasives include particles prepared by polymerizing a methyl methacrylate monomer or the like. The organic abrasive may have a single-layer structure or a capsule structure having a plurality of layers. The average volume particle size of the organic abrasive is suitably from 5 nm to 500 nm, preferably from 10 nm to 400 nm. The reason for limiting the particle size in this way is that if it is smaller than 5 nm, there is no polishing effect of removing the fluidizing agent of the developing roller, and if it is larger than 500 nm, the fluidity of the toner is reduced. The amount of the organic abrasive used is 0.05 to 5 parts by weight, preferably 100 parts by weight of the toner particles.
It is appropriate to use 0.1 to 3 parts by weight. The reason for limiting the amount of use in this way is that if the amount is less than 0.05 part by weight, the polishing effect is lost, and if the amount is more than 3 parts by weight, the fluidity of the toner is reduced.

Further, the present inventors conducted research on a developing device. As a result, the Asker F hardness of the elastic layer of the toner supply roller was reduced and the toner supply was performed so as not to hinder the supply and recovery of the toner. The inventors have found a range in which the pressing force of the roller against the developing roller can be reduced, and have completed the developing device of the present invention.

That is, the present invention provides a toner supply comprising a toner containing toner particles and a fluidizing agent added to impart fluidity to the toner particles, and a toner supply having an elastic layer for adhering the toner on the peripheral surface. In a developing device including a roller and a developing roller to which the toner supply roller is pressed and toner attached to the elastic layer is supplied, the elastic layer is formed by Asker F
The hardness is set to 40 ° to 60 °, and the average contact pressure between the toner supply roller and the developing roller is 1.0 × 10 ^{−3 to} 4.4 × 10 ⁻³ Kg / mm ²
Characterized by being pressed so that

Another aspect of the present invention is a toner having toner particles and a fluidizing agent added to impart fluidity to the toner particles, and a toner having an elastic layer for adhering the toner on a peripheral surface. In a developing device including a supply roller and a developing roller to which the toner supply roller is pressed and toner attached to the elastic layer is supplied, the elastic layer has an Asker F hardness of 40 ° to 60 °, The toner supply roller is pressed against the developing roller so that the amount of compressive deformation of the elastic layer is 0.5 mm to 2.0 mm.

FIG. 3 is an explanatory diagram of the amount of compressive deformation. The amount of compressive deformation in the present invention is, as shown in the drawing, the bearing distance (c) between the developing roller bearing shaft and the toner supply roller shaft from the sum (a + b) of the radius a of the development roller 2 and the radius b of the toner supply roller 4. ), Which is the size of the depression caused by the contact pressure at the contact portion between the toner supply roller 4 and the developing roller 2. Further, the toner used in the developing device of the present invention is not particularly limited, but a toner produced by a polymerization method in which particles are more spherical is preferable, and the above-mentioned toner of the present invention is particularly optimal.

According to the present invention, by preventing the deterioration of the toner, the printed portion is blurred due to the deterioration of the charging characteristics of the toner, the aggregation due to the decrease in the fluidity of the toner, the occurrence of the stain caused by the aggregation, and the toner potential It is possible to provide a developing device capable of eliminating fine print collapse and uneven print density due to an abnormal rise in image quality, and as a result, capable of forming a clear image even when used continuously for a long period of time.

Further, by using the toner of the present invention, a sufficient amount of toner can be supplied and collected with a minimum amount of the fluidizing agent, and the afterimage of the developing roller pitch does not occur.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments. (Embodiment 1) FIG. 1 is a sectional view showing the structure of the developing device of the present invention. The portion indicated by reference numeral 1 in FIG. 1 is a photoconductor drum, which comprises a conductive base layer of aluminum or the like and a photoconductor layer formed on the outer peripheral surface thereof. The photosensitive drum 1 is driven to rotate at a predetermined process speed in the direction of the arrow. Reference numeral 2 denotes a developing roller. The developing roller 2 has a rubber elastic body layer having high hardness such as semiconductive silicone rubber or urethane rubber around a conductive shaft, and a surface of the rubber elastic body layer. Is polished to (ten-point average roughness) = about 6 to 12 μm so that a good print density can be obtained. Reference numeral 3 denotes a toner. The toner 3 is obtained by pulverizing or polymerizing a thermoplastic resin such as a styrene resin and a polyester resin. Reference numeral 4 denotes a toner supply roller. The toner supply roller 4 has a foamed rubber elastic layer such as a silicone sponge or a urethane sponge formed around a conductive shaft.

The toner supply roller 4 is arranged so as to be pressed against the developing roller 2 and rotates in the same direction as the developing roller 2 as indicated by an arrow. The toner supply roller 4 functions to supply the toner 3 to the developing roller 2 by this rotational movement, to frictionally charge the toner at a contact portion with the developing roller, and to scrape unused toner 5 on the developing roller.
Reference numeral 6 denotes a developing blade made of a thin plate made of metal such as stainless steel. When the toner supplied onto the developing roller 2 passes through the developing blade 6, the toner is thinned and is further charged by friction with the developing blade 6.

In the present invention, a toner supply roller 4 having a rubber elastic layer having an Asker F hardness of 40 to 60 degrees is used, and the average contact pressure between the developing roller 2 and the toner supply roller is reduced.
It is characterized by being set to 1.0 × 10 ^{−3 to} 4.4 × 10 ⁻³ Kg / mm ² . In the present embodiment, it was found that it is preferable to set the average contact pressure to set the amount of compressive deformation at the contact portion between the developing roller and the toner supply roller to 0.5 mm to 2.0 mm in order to compensate for the decrease in frictional charge of the toner. Based on the evaluation, the developing device of the present invention was evaluated.

That is, using an Asker F hardness meter, a plurality of toner supply rollers each having a hardness of 30 ° to 60 ° at the point where the surface of the elastic layer and the pressing surface of the hardness meter become uniform, are prepared. A developing device was prepared in which the amount of compressive deformation at the contact portion between the developing roller and the toner supply roller was from 0.3 mm to 2.0 mm, and printing was actually performed. The results are shown in Table 1. The amount of compressive deformation refers to the size of a depression caused by a contact pressure at a contact portion between the toner supply roller 4 and the developing roller 2 as shown in FIG.

[0029]

[Table 1]

As is clear from Table 1, when the Asker F hardness of the elastic layer of the toner supply roller is smaller than 40 °, and the amount of compressive deformation at the contact portion with the developing roller is 0.5 mm
If it is smaller, dirty printing has occurred. This is because the hardness of the elastic layer and the pressing force were reduced, and the force of the toner supply roller to scrape off unused toner on the developing roller was reduced. it is conceivable that.

On the other hand, the Asker F hardness of the elastic layer is 40 °-
It is in the range of 60 ° and the amount of compression deformation with the developing roller is 0.
In the case of 5 mm or more, there are no defects such as fading, toner drop, and stain printing. This is because the elastic layer is set to the optimal hardness and the pressure at the contact portion between the developing roller and the toner supply roller is set to the minimum pressure necessary for toner supply and recovery, so that damage to the toner is reduced. This is because the. In addition, by increasing the amount of compressive deformation of the elastic layer of the toner supply roller, the time during which the toner is rubbed is increased, the unused toner on the developing roller is sufficiently scraped off, and the toner is newly supplied. This is because sufficient triboelectricity can be obtained for the toner.

As apparent from the first embodiment of the present invention, the elastic layer of the toner supply roller is
Hardness is 40 to 60 mm, and the amount of compressive deformation at the contact point of the toner supply roller with the developing roller is 0.5 to 2.0 mm
As a result, an image free from blurring, toner removal, and smear printing was obtained even after printing 30,000 sheets.

(Embodiment 2) In Embodiment 1, the developing device of the present invention improved by setting the hardness of the elastic layer of the toner supply roller and the contact pressure between the toner supply roller and the developing roller was described. In the second embodiment, in addition to this, the elastic layer of the toner supply roller is formed of closed cells having cells of an appropriate size, instead of continuous cells, and is excellent even when printing with higher resolution is performed. An attempt was made to obtain an image without blurring, detoning, and smearing printing in print quality. Here, the open cells refer to a structure in which the individual cells constituting the elastic layer are connected to each other by holes in the partition walls, and are in a state where gas and toner can move in the elastic layer. In contrast, closed cells refer to a structure in which individual cells constituting an elastic layer are separated by partition walls without holes,
In this state, gas and toner cannot move in the elastic layer.

In the second embodiment, the hardness of each elastic layer is set to Asker F hardness of 50 °, one is provided with an elastic layer having closed cells having different cell diameters, and the other is provided with continuous cells having different cell diameters. A plurality of toner supply rollers each having an elastic layer having bubbles were prepared, and a developing device having the same configuration as that of Example 1 was manufactured. That is, the amount of compressive deformation of each elastic layer is 1.
It was set to 0 mm. Cell diameter of each elastic layer is 0.1mm to 0.5mm
The printing was actually performed using such a toner supply roller and evaluated. Table 2 summarizes the results.

FIG. 4 is a conceptual diagram of an apparatus for examining the surface structure of the toner supply roller. In this example, the cell diameter of the elastic layer was measured by the following method. That is, as shown in FIG. 4, the surface of the toner supply roller 4 is irradiated with light from the light sources 8 on both sides, and the CCD camera 9 captures an enlarged image of the elastic layer surface of the toner supply roller 4.

FIG. 5 is an enlarged view showing the surface of the elastic layer having closed cells. In the photographed image, only the wall portion of the cell is photographed as shown in FIG.
The inside of the cell hole is shaded and blackened.

FIG. 6 is an explanatory diagram of a graph obtained by drawing a straight line AB at an arbitrary position on the image of FIG. 5 and measuring the luminance at each point on the straight line. In FIG. 6, when the average luminance 11 is set to be linear, the portion 12 having a higher luminance than the average luminance indicates a cell wall, and the average distance between the walls is calculated as the cell diameter.

[0038]

[Table 2]

As is clear from Table 2, when the closed cell elastic layer is formed, if the cell diameter is from 0.15 mm to 0.4 mm, no print collapse occurs even in high-resolution printing. Became. If the cell diameter is larger than 0.4 mm, the unused toner on the developing roller is scraped off at the hole of the cell and the toner supply becomes insufficient. As a result, image collapse and halftone unevenness occur on the image. Conversely, when the cell diameter was smaller than 0.15 mm, print fading and toner dropping occurred. On the other hand, when printing is performed by forming an elastic layer of open cells, the toner enters the elastic layer, and print blurring or the like increases.

As a result of using the developing device of Example 2, 30,000
Even if you print sheets at high resolution, there is no image collapse,
Further, it was possible to obtain an image without blurring of the print or toner drop to the end.

(Embodiment 3) In this embodiment, the toner of the present invention produced by the polymerization method is applied to the developing device of the present invention described in the first embodiment.

Hereinafter, the method for producing the toner of the present invention will be described. First, toner particles having a two-layer structure were produced by a suspension polymerization method. That is, 75 parts by weight of styrene, acrylic acid-
To 25 parts by weight of n-butyl, 1.5 parts by weight of low molecular weight polyethylene as an anti-offset agent, 1 part by weight of a charge control agent "Eizen Spiron Black TRH" (manufactured by Hodogaya Chemical Co., Ltd.), and 7 parts by weight of carbon black (manufactured by Printex L Degussa) Department and
One part by weight of 2,2'-azobisisobutyronitrile was added and charged into an attritor ("MA-01SC", manufactured by Mitsui Miike Kakoki Co., Ltd.). Next, these materials are heated at 15 ° C by an attritor.
The mixture was dispersed for 10 hours to obtain a polymerizable composition.

On the other hand, 600 parts by weight of distilled water was added to 180 parts by weight of ethanol in which 8 parts by weight of polyacrylic acid and 0.35 part by weight of divinylbenzene were dissolved to prepare a dispersion medium for polymerization. Next, the polymerizable composition is added to the dispersion medium,
Using a TK homomixer (“M type”, manufactured by Tokushu Kika Kogyo Co., Ltd.), the mixture was dispersed at 15 ° C. and 8,000 rpm for 10 minutes. The obtained dispersion solution was transferred into a 1-liter separable flask, and stirred at 100 rpm under a nitrogen stream.
The reaction was performed at 5 ° C. for 12 hours. At this stage, the dispersoid obtained by the polymerization reaction of the polymerizable composition is called an intermediate particle.

Next, using an ultrasonic oscillator (US-150, Nippon Seiki Seisakusho), 9.5 parts by weight of methyl methacrylate, 0.5 part of n-butyl acrylate, and a polymerization initiator were used.
A water emulsion A comprising 0.5 parts by weight of 2,2'-azobisisobutyronitrile, 0.1 part by weight of sodium lauryl sulfate and 80 parts by weight of water was prepared. Then, 9 parts by weight of the water emulsion A was dropped into the aqueous suspension of the intermediate particles to swell the intermediate particles. Observation with an optical microscope immediately after dropping confirmed that no emulsion droplets were observed and that swelling was completed in a very short time.

Then, the reaction was carried out at 85 ° C. for 10 hours as a second stage polymerization while stirring was continued in a nitrogen environment. After cooling, the dispersion medium was dissolved in a 0.5N hydrochloric acid aqueous solution, filtered, washed with water, air-dried, dried at 40 ° C. for 10 hours under reduced pressure of 10 mmHg, and classified using an air classifier to obtain a toner having an average particle diameter of 7 μm. Particles were obtained. In the following Examples and Comparative Examples, the toner of the present invention was manufactured by adding a predetermined amount of an inorganic fluidizing agent and / or an organic abrasive to the toner particles.

In this embodiment, the hydrophobic silica fine particles R202.
0.3 parts by weight of Nippon Aerosil Co., Ltd.) were added and mixed to obtain a toner of the present invention. As a result, the amount L of the inorganic fluidizing agent (R202) added to the toner particles was 0.021. Here, when the initial flow characteristics of the toner of the present invention were measured by a cohesion degree method, it was 90. That is, in this example, the fluidity of the toner was measured as follows. First, 20 g of the sample toner was placed on a sieve having a mesh of 45 μm, and vibration was applied at a frequency of 1 KHz for 30 seconds. Then, the remaining amount of the toner remaining on the sieve was measured, and the fluidity was calculated by the following equation. Fluidity (%) = (1−Remaining amount of toner remaining on sieve)
(g)) / Sample toner weight (g) x 100

(Evaluation of Initial Print Density) 130 g of the toner obtained in this example was charged into the developing device shown in FIG. 1, and continuous printing was performed using A4 paper at a print duty (proportion of print dots) of 2.5%. The toner supply roller of the developing device used has an elastic layer made of silicone foam, and is made of the same material and has the same thickness.
A surface layer having a thickness of 0.1 μm and a ten-point average roughness of 0.1 μm is formed. The elastic layer of the toner supply roller has an Asker F hardness of 50 ° and the amount of compressive deformation with respect to the developing roller is 1.
It is set to 0mm. The initial print density was 1.3 with a Macbeth densitometer, which was a sufficient print density.

For comparison, a toner supply roller having an elastic layer having a different hardness and a plurality of toners having different addition amounts of an inorganic fluidizing agent were prepared. Table 3 shows the relationship between the combination with the amount of the fluidizing agent (R202) and the presence / absence of density unevenness.

As is apparent from Table 3, Asker F hardness
When a toner supply roller having an elastic layer of 30 mm is used,
Irrespective of the amount of the inorganic fluidizer, concentration unevenness occurred. This is considered to be because the supply and recovery of the toner were not performed uniformly because the contact pressure between the toner supply roller and the developing roller was insufficient. In a system using a toner supply roller having an elastic layer having an Asker F hardness of 30 ° or less, this tendency did not change even if the amount of compressive deformation was 2 mm or more. Next, when a toner supply roller having an elastic layer having an Asker F hardness of 40 to 60 mm is used, regardless of the amount of the inorganic fluidizing agent added, the density unevenness is reduced up to a compression deformation amount of 0.5 mm to 2.0 mm. When the thickness was 0.4 mm or less, density unevenness tended to occur.

[0050]

[Table 3]

(Evaluation after continuous printing) Using the same toner supply roller and toner as used for the evaluation of the initial print density, continuous printing was performed on 8,000 sheets.
6 is shown. Table 4 shows the presence or absence of blurring of the image after continuous printing. That is, when the Asker F hardness of the elastic layer of the toner supply roller is set to 30 ° to 60 ° and the amount of compressive deformation is set to 0.5 mm to 2.0 mm, even if the addition amount of the inorganic fluidizing agent (R202) is different, Image blurring did not occur. Further, as shown in Table 5, it was confirmed that the fluidity of each toner was maintained at 70 to 79 even after continuous printing, and there was no deterioration.

However, the Asker F hardness of the elastic layer is 40 ° or more.
When the amount of compressive deformation was set to 2.5 mm or more even in the 60 mm system, blurring was observed in the continuously printed image, and the toner fluidity at this time was found to be about 30 or less. From this result, it was found that even with a toner supply roller having a soft elastic layer, if the pressing force against the developing roller is excessive, the deterioration of the toner is accelerated.

When the elastic layer of the toner supply roller is set to Asker F hardness 70 °, the amount of compressive deformation is 1 mm.
Print fading occurred even when set to. The fluidity at this time was 35 or less. On the other hand, even if the Asker F hardness of the elastic layer is set to 70 °, the inorganic fluidizer (R202)
Is added to the toner particles, that is, when the addition amount L of the inorganic fluidizing agent (R202) to the toner particles is set to 0.086, the occurrence of print fading can be prevented, and the fluidity of the toner at that time is reduced.
It was relatively high at 46.

As described above, the Asker F hardness of the elastic layer of the toner supply roller is 30 ° to 60 °, and the amount of compressive deformation is
In the range of 0.5 mm to 2.0 mm, the addition amount L of the inorganic fluidizing agent is 0.
For each of the toners 004 to 0.086, the fluidity was maintained at 70 or more, and no deterioration of the toner was observed even after continuous printing. On the other hand, when the Asker F hardness of the elastic layer was 70 °, the fluidity of the toner was significantly reduced.

That is, as is apparent from Tables 4 and 5, the Asker F hardness of the elastic layer is 30 ° to 60 °, and the amount of compressive deformation is 0.1 mm.
When it is set to 5 mm to 2.0 mm, the addition amount L of the inorganic fluidizing agent is 0.
In the range of 004 to 0.086, image blurring does not occur, and the fluidity of the toner is good. From the above, it can be seen that, after continuous printing, there is a strong correlation between the presence or absence of print blur shown in Table 4 and the measured value of the fluidity of the toner remaining in the developing device shown in Table 5.

[0056]

[Table 4]

[0057]

[Table 5]

Next, the background on the photosensitive drum after continuous printing was measured. Table 6 shows the results. This background fog was measured using a spectrophotometer Minolta CM-
It measured by the following method using 1000. A 3M scotch tape was attached to A4 paper used for printing, and the reflectance was measured with the same colorimeter. Next, the image forming apparatus during printing is momentarily interrupted, and the EP cartridge (developing device) is taken out. Here, a 3M scotch tape was stuck on the surface of the photoconductor drum before the development process was completed and before the transfer process was started, and the background fog toner adhering to the surface was transferred to the tape. Next, this tape is attached to the A4 paper, and the reflectance is measured by the spectrophotometer. The value of this reflectance is B. And numerical value AB (%)
Is defined as background fog. The fog is desirably 10% or less, and thus 10% is used as a criterion for the quality of print.

As is clear from Table 6, when the total amount of the inorganic fluidizer (R202) added was 0.8 parts by weight or less, the fog was 2%.
-5%, which means that the printing quality is good even when printing is performed thereafter. In contrast, inorganic fluidizers
At 0.9 parts by weight or more, the fog exceeded 10% and the print quality was clearly deteriorated. This is because the excess inorganic fluidizing agent is separated from the toner particle surface during continuous printing, and the separated inorganic fluidizing agent is firmly attached to the surface of the developing roller, thereby preventing frictional charging of the toner. Can be estimated. In other words, after cleaning the surface of the developing roller after continuous printing by rubbing it strongly with alcohol, and printing again using the toner used in continuous printing, fogging was almost completely returned to the initial state. It is clear from that.

Therefore, as is apparent from the present embodiment, by using the toner supply roller according to the present invention with a predetermined pressing force and utilizing the toner of the present invention, the print quality in continuous operation can be improved. Can be kept. Further, as is clear from Table 6, the use of the toner of the present invention in which the addition amount L of the inorganic fluidizing agent to the toner particles is set to 0.007 to 0.057 can effectively prevent background fog. The same result was obtained by using a toner supply roller having an elastic body layer made of urethane and having a surface layer having a thickness of 0.1 μm and a ten-point average roughness of 0.1 μm.

[0061]

[Table 6]

As described above, by setting the hardness of the elastic layer of the toner supply roller to the Asker F hardness of 40 ° to 60 ° and the amount of compressive deformation of the roller to 0.5 mm to 2.0 mm, toner supply and recovery can be performed. The smoothing can be performed, and the mechanical stress applied to the toner can be minimized. Further, when the toner of the present invention in which a predetermined amount of the inorganic fluidizing agent is added to the toner particles having a curved surface is used, background fog can be prevented while ensuring the fluidity of the toner, and therefore, the occurrence of print blur in continuous printing can be prevented. Can be suppressed.

(Example 4) To 100 parts by weight of the toner particles having the same curved surface as in Example 3, 0.3 part by weight of an inorganic fluidizing agent RX50 (silica, particle size of 40 nm, manufactured by Nippon Aerosil Co., Ltd.) was added and mixed. A toner of the present invention was produced. Therefore, the addition amount L to the toner particles is 0.008 (see Table 7). The initial fluidity of the toner measured by the agglomeration degree method was 90. When the same evaluation test as in Example 3 was performed using this toner, the results shown in Tables 7 to 10 were obtained.

That is, as shown in Table 7, the Asker F hardness
When a toner supply roller having an elastic layer of 40 ° to 60 ° is used, in a range where the amount of compressive deformation is set to 0.5 mm to 2.0 mm,
Without being affected by the amount of inorganic fluidizer (RX50)
Density unevenness did not occur, and when it was 0.4 mm or less, density unevenness occurred. Further, Asker F hardness of the elastic layer is 30 ° to 60 °.
°, when the amount of compressive deformation is set to 0.5 mm to 2.0 mm, no image blur occurs even in continuous printing as shown in Table 8, and as shown in Table 9, even if continuous printing, The fluidity remained above 70. Further, when the addition amount L of the inorganic fluidizing agent (RX50) to the toner particles is in the range of 0.008 to 0.060, the amount of the inorganic fluidizing agent attached to the developing roller is small, and therefore, the toner can be sufficiently triboelectrically charged. Even after continuous printing, the background fog was extremely low, as shown in Table 10, as 1 to 4%, and thus the print quality could be maintained satisfactorily thereafter.

[0065]

[Table 7]

[0066]

[Table 8]

[0067]

[Table 9]

[0068]

[Table 10]

(Example 5) The same toner particles 10 as in Example 3
0 parts by weight, 0.2 parts by weight of silica RX50 (individual particle diameter 40 nm, manufactured by Nippon Aerosil Co., Ltd.) and 0.1 parts by weight of silica R202 (individual particle diameter 14 nm, manufactured by Nippon Aerosil Co., Ltd.) In addition, they were mixed to produce the toner of the present invention. Therefore, the addition amount L to the toner particles is 0.012 (see Table 11). The initial fluidity of this toner was measured by the cohesion degree method, and was found to be 90. The same evaluation test as in Example 3 was performed using this toner.
~ The results shown in Table 14 were obtained.

That is, as shown in Table 11, when a toner supply roller having an elastic layer having an Asker F hardness of 40 ° to 60 ° is used, the density unevenness is limited in a range where the amount of compressive deformation is set to 0.5 mm to 2.0 mm. Did not occur, and density unevenness occurred below 0.4 mm. Further, Asker F hardness of the elastic layer is 30 ° to 60 °,
When the amount of compressive deformation is set to 0.5 mm to 2.0 mm, as shown in Table 12, no image blur occurs even in continuous printing, and as shown in Table 13, the fluidity of each toner maintains 70 or more. did. Further, when the addition amount L of the inorganic fluidizing agent (RX50, R202) to the toner particles is in the range of 0.012 to 0.058, the background fog is extremely low at 1 to 3% as shown in Table 14.

[0071]

[Table 11]

[0072]

[Table 12]

[0073]

[Table 13]

[0074]

[Table 14]

Further, the addition ratios of silica RX50 and R202 are (0.1, 0.2), (0.05, 0.25),
(0.25, 0.05) were added to produce the toner of the present invention, and the same evaluation test as in Example 3 was performed.
As is clear from these results, it was confirmed that the state of deterioration of the toner after continuous printing was not affected by the type of inorganic fluidizing agent and the mixing ratio thereof, but was determined by the total amount of addition.

Example 6 A toner supply roller having an Asker F hardness of 50 ° and an elastic layer having closed cells with a cell diameter of 30 mm was prepared, and the amount of compression deformation of the toner supply roller with respect to the developing roller was 3 × 10 ^−. A developing device set at ³ kg / mm ² was manufactured, and continuous printing was performed using the toner of the present invention shown in Example 3, and the results were evaluated. Table 15 summarizes the results.

In the developing device of the third embodiment, the initial print density was 1.3 with a Macbeth densitometer, whereas in the developing device of the present embodiment, the density was as large as 1.5 under the same conditions as in the third embodiment. This is considered to be because the toner supply roller of the present embodiment is superior in toner supply property to the toner supply roller of the third embodiment. Therefore, in the present embodiment, the rotation speed ratio of the toner supply roller to the developing roller is set to 1/2 of that of the third embodiment, and the same density of 1.3 as in the third embodiment is obtained.

When the same evaluation test as in Example 3 was performed under these conditions, the toner fluidity and the degree of print blurring were reduced to the levels of 8,000 sheets printed in Example 3 when the number of printed sheets was 12,000. When the number of printed sheets was 8,000, the deterioration of the toner was smaller than that of the third embodiment. Table 15 shows the results. The reason why the deterioration of the toner is small is that although the surface of the toner supply roller is in a foaming state, the mechanical surface roughness is increased, but the rotational speed of the toner supply roller can be reduced, so that the contact pressure applied to the toner at the time of friction charging is reduced. It is considered that the size of the toner can be reduced, and therefore the deterioration of the toner is small.

[0079]

[Table 15]

In this embodiment, when a plurality of toner supply rollers having elastic layers having different cell diameters were prepared and subjected to the same evaluation test, the optimum cell diameter was in the range of 0.15 mm to 0.40 mm. there were. When the cell diameter is smaller than 0.15mm,
In particular, when the thickness is 0.05 mm or less, toner clogging tends to occur near the surface of the elastic layer. If the clogging is large, the amount of supplied toner becomes unstable, and density unevenness occurs in an image. Further, when the cell diameter exceeded 0.4 mm, particularly when the cell diameter exceeded 0.5 mm, halftone mesh unevenness became noticeable on printing.

As described above, when the elastic layer of the toner supply roller has a closed cell shape and is set to a cell diameter of 0.15 to 0.40 mm, excellent toner supply properties can be ensured. , The desired print density can be obtained. As a result, the deterioration of the toner can be further suppressed, so that the occurrence of print blur due to continuous printing can be reduced. Further, as in Example 3, the amount of the inorganic fluidizing agent added could be reduced, so that fogging was small even when continuous printing was performed.

Example 7 In this example, the same suspension polymerization as in Example 3 was carried out once using a methyl methacrylate monomer as an abrasive raw material to obtain a single-layer structure and an average volume particle size.
An organic abrasive of 0.3 μm spherical particles was prepared. Then, as in Example 3, a plurality of toners were manufactured by adding 0.3 parts by weight of the organic abrasive to 100 parts by weight of each toner having a different amount of the inorganic fluidizing agent. When the same evaluation test as in Example 3 was performed using these toners, the same results as in Example 3 were obtained except for the evaluation of fogging after continuous printing. Table 16 shows the results.

As is clear from Table 16, when the continuous printing of 8,000 sheets was completed by using the toner to which the organic abrasive was added, when the toner having the inorganic fluidizing agent amount of 0.8 parts by weight or less was used, the fogging was performed. Was zero, and the fog after continuous printing of 12,000 sheets was almost the same as the fog at the end of continuous printing of 8,000 sheets in Example 3. This is presumably because the polishing effect of the organic polishing agent prevented the inorganic fluidizing agent from adhering to the surface of the developing roller, and the adhered inorganic fluidizing agent was removed. On the other hand, as is apparent from Table 16, even when an organic abrasive is added, it is difficult to suppress fog in continuous printing when a toner with a large amount of the inorganic fluidizing agent is used.

Incidentally, toners were prepared by adding an inorganic abrasive having the same volume average particle diameter as the organic abrasive of the present embodiment. However, when these were printed on several hundred sheets, the abrasives were released from the toner. It did not endure practical use.

[0085]

[Table 16]

As described in the present embodiment, it can be seen that the addition of the organic abrasive to the toner can effectively suppress the occurrence of fogging in continuous printing as compared with the third embodiment. Further, by using the toner manufactured by the polymerization method in the same manner as in Example 3, it is possible to employ a toner supply mechanism which facilitates the toner supply property and minimizes the mechanical stress applied to the toner. The occurrence of print fading due to deterioration was also suppressed.

Comparative Example A pulverized toner material was prepared using a material having the same composition as the toner of Example 3, finely pulverized by a jet mill, and then classified so as to have the same particle size as the toner particles of Example 3. Thus, pulverized toner particles were obtained. This toner particles 100
In parts by weight, as in Example 3, silica as an inorganic fluidizing agent was used.
A pulverized toner was manufactured by adding 0.05 to 1.2 parts by weight of R202, and the same evaluation test as in Example 1 was performed. Inorganic fluidizer
With 1.2 parts by weight of added toner, no print fading occurred after continuous printing, but background fog was 30
%. In addition, in the toner in which the addition amount of the inorganic fluidizing agent was 1.0 part by weight or less, print fading occurred. further,
The fluidity of toner after continuous printing of 8,000 sheets is about 10
This was before and after, and was significantly lower than the corresponding toners of Example 3.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing a configuration of a developing device of the present invention.

FIG. 2 is a cross-sectional view illustrating a general configuration of the entire developing device.

FIG. 3 is a cross-sectional view illustrating the relationship between the configuration of a developing roller and a toner supply roller and the amount of compressive deformation.

FIG. 4 is a conceptual diagram of an apparatus for examining a surface structure of a toner supply roller.

FIG. 5 is an enlarged view showing an elastic layer surface of the toner supply roller.

FIG. 6 is an explanatory diagram of a cell of an elastic layer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor drum 2 Developing roller 3 Toner 4 Toner supply roller 5 Unused toner 6 Developing blade 7 Toner cartridge 8 Light source 9 CCD camera 11 Average brightness

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Koichi Ando 4--11-12 Shibaura, Minato-ku, Tokyo Inside the company offshore data (72) Inventor Takao Mizutani 4-11-22 Shibaura, Minato-ku, Tokyo Shares (72) Inventor Masao Isoda 4-11-11 Shibaura, Minato-ku, Tokyo In-office data

Claims (11)

[Claims] 1. A toner comprising toner particles and a fluidizing agent added to impart fluidity to the toner particles, wherein the toner particles are formed from a curved surface, and the toner particles of the fluidizing agent are provided. L added to
, The type of the fluidizing agent is n, and the
(N) When the particle size of the fluidizing agent n alone is K (n), the following formula is satisfied: L = 0.07 <Σ (M (n) / K (n)) <0.060. toner. 2. The toner according to claim 1, wherein the toner particles are produced by a polymerization method. 3. A polishing method according to claim 1, wherein said fluidizing agent separated from said toner particles is prevented from adhering to a developing roller, and said fluidizing agent is removed from said developing roller. A toner comprising an agent. 4. The toner particles and fluidity on the toner particles
Toner containing a fluidizing agent added to impart
Having an elastic layer for attaching the toner to the toner
A supply roller and the toner supply roller are pressed,
A developing roller to which the toner attached to the elastic layer is supplied;
Wherein the elastic layer has an Asker F hardness of 40 ° to 60 °.
Wherein the toner supply roller has an average contact pressure with the developing roller.
Is 1.0 × 10^-3~ 4.4 × 10 ^-3Kg / mm^TwoIs pressed to become
A developing device. 5. The developing device according to claim 4, wherein the elastic layer is made of a foam having closed cells, and a cell diameter is set to 0.15 mm to 0.4 mm. 6. The developing device according to claim 4, wherein the toner particles are formed from a curved surface. 7. The developing device according to claim 4, wherein the toner particles are formed from a curved surface, and the amount of the fluidizing agent added to the toner particles is L.
, The type of the fluidizing agent is n, and the
(N) When the particle size of the fluidizing agent n alone is K (n), the following formula is satisfied: L = 0.07 <Σ (M (n) / K (n)) <0.060. Developing device. 8. A toner supply comprising toner particles and a fluidizing agent added to impart fluidity to the toner particles, a toner supply roller having an elastic layer for adhering the toner on a peripheral surface, A developing roller to which the toner supply roller is pressed and to which the toner attached to the elastic layer is supplied, wherein the elastic layer has an Asker F hardness of 40 ° to 60 °, A developing device, wherein a supply roller is pressed against the developing roller so that an amount of compressive deformation of the elastic layer is 0.5 mm to 2.0 mm. 9. The developing device according to claim 8, wherein the elastic layer is made of a foam having closed cells, and a cell diameter is set to 0.15 mm to 0.4 mm. 10. The developing device according to claim 8, wherein the toner particles are formed from a curved surface. 11. The developing device according to claim 8, wherein the toner particles are formed from a curved surface, and the amount of the fluidizing agent added to the toner particles is L.
, The type of the fluidizing agent is n, and the
(N) When the particle size of the fluidizing agent n alone is K (n), the following formula is satisfied: L = 0.07 <Σ (M (n) / K (n)) <0.060. Developing device.