JP3373376B2 - Image forming device - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to uses an amorphous silicon photosensitive member as an image bearing member, thereby developing the latent image on the photosensitive member, an image with a developing apparatus which performs also as a recovery of the remaining residual toner Forming apparatus

[0002]

2. Description of the Related Art In recent years, some photosensitive drums used in electrophotographic apparatuses use an a-Si drum for the purpose of improving durability and achieving free maintenance.
Since i has a higher hygroscopicity than organic semiconductors, and therefore the image flow easily occurs in the a-Si drum under high humidity, a sheet heater or other heating element is provided on the back side of the photosensitive drum. Is arranged and the photosensitive drum is heated to prevent the image deletion.

However, the provision of the heater not only complicates the construction because it also requires a heat control means, but especially when the heater is used in downsizing and personalization of copying machines and printers, the system becomes complicated. turn into.
Further, it takes a certain amount of time to raise the temperature of the heater, and the time from warming up to printing (warm-up time) is long, and power consumption for that is required. When the photoconductor is heated, the TG temperature of the toner (glass transition temperature)
Since the temperature is raised to near, the toner adheres to the surface of the photoconductor. Various problems occur.

Even in the case where the image deletion does not occur, in the electrophotographic apparatus of this type, toner is attached to the developing area of the electrostatic latent image formed on the photosensitive member in the developing process, and the toner is applied to the non-developing area. In order to prevent adhesion, the surface potential of the photoconductor is set to 400 V or more in the charging step, and the difference between the high potential portions of the electrostatic latent image formed in the exposure step is set to 400 V.
In addition, the development potential needs to be 200 V or higher. Therefore, a photoconductive material having a charging ability of 400 V or more is required for the photoconductor, and there are great restrictions in selecting the material and setting the film thickness.

Further, a-Si is apt to cause a so-called "fogging" phenomenon in which toner adheres to a white background portion. This is a phenomenon in which toner in the device adheres to the surface of the photoconductor due to image force or the like. The mirror image force of the toner is greatly affected by the relative permittivity of the photosensitive layer, and the higher the relative permittivity, the greater the mirror image force. This relative dielectric constant is usually 3 to 3 for organic photoconductors.
Since it is 3.5, which is as large as 10 to 12 for a-Si, the "fog" phenomenon is likely to occur in a-Si.

Conventionally, a pulverized toner has been used. In this pulverized toner, a kneaded material in which small particles such as a resin, a colorant and a charge control agent are mixed is cooled and then coarsely pulverized by a hammer mill, a cutter mill, etc. Particle size 8 to 1
It is made by finely pulverizing to about 5 μm. Although it is relatively easy to create, it is created in a distorted shape with irregularities, and the charge tends to concentrate on the convex parts, and there are cases where multiple convex parts contact one particle with the photoreceptor surface. At that time, the image power becomes large.

[0007]

As a technique for solving the above-described image deletion by using an abrasive, Japanese Patent Publication No. 7-113787.
Japanese Patent Publication (Prior Art 1) is known. In this technique, the abrasive particles (B) are fixed to the colored particles (A) having a binder resin and a colorant by mechanical impact, and the colored particles (A) are spherical particles having few protrusions. It is disclosed as preferred.

However, in this prior art example 1, W1: weight of particles (A), W2: weight of particles (B), R1: average particle diameter of particles (A), R2: average particle diameter of particles (B). , M
1: where the true density of the particles (A) and M2: the true density of the particles (B), the coverage% of the abrasive particles (B) on the colored particles (A) = (W2
XR1xM1x100) / (4xW1xR2xM2) is set to 0.1 to 10%, and a high level of technology is required to control this coverage. is there.

As a technique for preventing the above-mentioned "fog" phenomenon, Japanese Patent Laid-Open No. 7-295388 (Prior example 2) is known. This technology uses polymerized toner,
Amorphous silicon photoconductor and developing roller carry out contact development, and one or more additives such as fluidity-imparting agent, abrasive, lubricant, charge control particles are used together, and 0.1 to 10% by weight based on the weight of toner. It is to be added.

However, in the second prior art, the residual toner is collected by the fog removing bias, and the prevention of the "fog" phenomenon is not always sufficient.

[0011] The present invention has been made in view of the above circumstances, a-Si, while the drum consideration the simplicity and safety of the structure using the image flow and image capable of forming a clear image is not to be 'head' phenomenon An object is to provide a forming device .

[0012]

The present invention is amorphous
The latent image on the silicon photoconductor was developed and remained.
An image with a developing device that also collects residual toner after transfer
In the forming device, the toner particles obtained by the polymerization method are
Immobilized abrasive particles by mechanical impact or thermal treatment
Later, using a toner formed by adding fine silica powder,
The surface layer of the photoreceptor is gradually hardened from the outermost surface side to the inner side.
Degree is increased, to develop the latent image into contact with the photosensitive member
Transfer residual toner remaining on the photoconductor by the developing roller
And the photoconductor by the abrasive particles.
It is characterized by polishing the surface.

Further, the polymerized toner is constituted by containing the abrasive particles in an amount of 0.3 to 5% by weight based on the toner weight, and the silica fine powder is added in an amount of 0.3 to 5% by weight based on the toner weight.
It is also effective means of forming the polymerized toner contains 2 wt%.

According to the present invention, the toner particles obtained by the polymerization method are fixed by the mechanical impact or the thermal treatment to fix the abrasive particles, and the fine silica powder is added to the toner particles. The abrasive particles are not electrostatically attached to the toner particles, but the abrasive particles are surely held by the toner particles in such a manner that a part of the abrasive particles is embedded in the toner particles,
A toner particle combination is formed.

Therefore, since the abrasive particles are held by the toner particle combination, even if the toner particles and the abrasive particles have the same polarity, they are separated from the toner particles by stirring in the developing device and the like, and the developing device is removed. Rarely stays inside, the surface of the photoconductor is abraded by the abrasive particles when scraping off the transfer residual toner remaining on the photoconductor by a developing roller that contacts the photoconductor to develop a latent image, It is possible to prevent fogging.

Further, since the present toner has a spherical shape (spherical shape or a shape close to a spherical shape) by the polymerization method, the curved surface of the toner particles is uniformly charged and comes into point contact with the surface of the photosensitive member. Both the image force and the van der Waals force are small, and the occurrence of fogging can be prevented.

Further, since the toner formed by adding fine silica powder to the toner particle combination is used, stable chargeability and fluidity are imparted to the toner, and good image formation can be performed. .

When the toner is formed by mixing abrasive particles charged to the opposite polarity to the toner particles and silica fine powder charged to the same polarity as the toner particles, the toner particles and the abrasive particles are mixed. In the adhesion, an electrostatic force other than the holding force in which a part of the abrasive particles is intruded into the toner particles is applied, and the toner particles can be prevented from falling off.

At this time, 0.3 to 5% by weight of the toner weight
Containing at least 3 to 2% by weight of toner of silica fine powder, and at least a plurality of abrasive particles and silica fine powder are attached to one toner particle. Is desirable.

[0020]

[0021]

[0022]

[0023]

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described in the present embodiment are not specifically intended to limit the scope of the present invention, and are simply described unless otherwise specified. It's just an example.

FIG. 1 shows an embodiment of an image forming apparatus to which the present invention is applied, in which a-Si rotating clockwise in the drawing.
An optical system including an LED LED head 2 for exposure and a SELFOC lens 3, a developing unit 4, a transfer roller 5, a discharging lamp 7, and a charging unit 8 are arranged around the photosensitive drum (photosensitive member) 1 along the rotation direction. It is set up.

Next, each component will be described.
As shown in A, the photosensitive drum 1 has a conductive support 1a.
A photoconductive layer 1b and a surface layer 1c are stacked on top of each other, and a carrier injection blocking layer 1e is provided between the conductive support 1a and the photoconductive layer 1b, and a photoconductive layer 1b and a surface layer 1c.
The transition layers 1f are respectively interposed between these. As the support 1a, an aluminum cylinder is generally used.
It is made of a metal material such as S, Ti, Ni, Au, Ag, an inorganic material such as glass having a conductive film deposited on the surface thereof, a transparent resin such as epoxy, or the like, and has a thickness of 3 in this embodiment.
mm and set the outer diameter to 30 mm, and 2 in the axial direction.
An aluminum cylinder having a length of 54 mm is used.

The carrier injection blocking layer 1e is the photoconductive layer 1
Although various materials are used depending on the material of b, when an a-Si based material is used for the photoconductive layer 1b, it is preferable to use the a-Si based carrier injection blocking layer 1e.

The a-Si photoconductive layer 1b is formed into a film by a glow discharge decomposition method, a sputtering method, an ECR method, a vapor deposition method or the like. In forming the film, an element for dangling bond termination, for example, (H) is used. And halogen 5-40w
It is preferable to contain t%. That is, the photoconductive layer 1b has a-
A photoconductor made of Si: H is used, and when the developing bias is positive, non-doped or a Va group element is contained in order to increase the mobility of electrons, and when the developing bias is negative, hole movement occurs. In order to increase the degree, it is preferable to include a Group IIIa element. If necessary, elements such as C, O and N may be contained in order to obtain desired characteristics such as electrical characteristics such as dark conductivity and photoconductivity, and optical bandgap.

The film thickness of the entire photoconductive layer 1b is
The thickness is preferably about 3 to 50 μm in order to secure the necessary charging and withstand voltage, absorb the exposed light, and suppress the above-mentioned residual potential.

The surface layer 1c has a thickness of 25 μm.
Glow discharge decomposition method, sputtering method, ECR
Film is formed by a vapor deposition method, a vapor deposition method, etc., and the element ratio composition formula (a-
Sil- xC_x: H), x is 0.95 ≦
Dynamic indentation of x <1 and the outermost surface (free surface layer)
Hardness is 50 to 200 Kgf / mm² Ammo hydroxide
It consists of rufus silicon carbide, especially
Resistance value 10¹²-10¹³Set the resistance value in the Ω · cm range.
It The surface layer 1c is the photoconductive layer 1b from the outermost surface side.
The hardness is gradually increased toward the inner side of the
Set.

To provide the above-mentioned hardness gradient (gradient in which the hardness gradually increases from the outermost surface side toward the inner side of the photoconductive layer 1b), for example, the surface layer 1c is glowed. In the case of forming a film by the discharge decomposition method, the ratio of the C-containing gas to the Si-containing gas in the source gas is gradually increased, the gas pressure during film formation is gradually increased, and the hydrogen gas of the source gas is used. It is formed by means such as gradually reducing the dilution rate by, gradually reducing the discharge power, and gradually lowering the temperature of the base of the aluminum cylindrical drum.

Further, between the photoconductive layer 1b and the surface layer 1c,
It is preferable to provide the transition layer 1f in which the C content in the a-SiC: H is smaller than the C content in the surface layer 1c. Further, the C content of the transition layer 1f may be changed in the layer so as to have a content gradient. Such a transition layer 1
By providing f, the traveling of the photocarriers generated in the photoconductive layer 1b becomes smooth, the photosensitivity is high, the residual potential is low, and the image characteristics are good.

The developing unit 4A shown in FIG. 2 includes a developing container 41 accommodating a non-magnetic one-component toner, a developing roller 40 including an elastic body 42 made of an elastic material such as urethane rubber, and toner for the roller 40. The developing roller 17 is provided with a developing blade 17 that regulates the layer thickness, and a supply roller 45A that supplies toner to the developing roller 40.
The supply roller 45, the developing blade 17 and the like have, for example, 50 to 50
DC developing bias power sources E1 (350V), E2 (350V), E3 (not shown) that can be arbitrarily set between 500V
It is connected to (120V) and is configured to perform development.

The outer circumference of the supply roller 45 is formed of a sponge which rotates in contact with the elastic body 42 of the developing roller 40. The supply roller 45 has a nip width of 1 mm or more and is in contact with the developing roller 40.

In the developing unit 4, as shown in FIG. 2, the supply roller 45A which rotates counterclockwise contacts and rubs against the development roller 40 which also rotates counterclockwise. 45, new toner 5
0 is supplied to the developing roller 40, and the toner layer thickness is 0.3 mg / cm by the developing blade 17 that regulates the toner layer thickness.
^It is regulated to ² to 0.9 mg / cm ² and supplied to the photoconductor 1.

On the other hand, the residual toner 49 of the toner which is not transferred to the recording paper 9 comes into contact with the elastic body 42 of the developing roller 40 again, and the developing roller 40 at the contact position with the photosensitive member 1 has a peripheral speed higher than that of the photosensitive member 1. , The residual toner 49 is scraped off by the elastic body 42 of the developing roller 40 as indicated by reference numeral 51, and new toner 48 develops the latent image on the surface of the photoconductor 1.

Further, as indicated by reference numeral 51, the developing container 41
The residual toner 52, which does not drop to the lower part inside and adheres to the developing roller 40, does not develop in the nip region where the developing roller 40 and the supply roller 45 influence each other.
The supply roller 45, which rotates in the direction opposite to 0, drops the developer container 41 and collects it, as indicated by reference numeral 53.

Now, a method of manufacturing the toner used in this embodiment will be described. First, in the step of polymerizing a polymer from a monomer, a colorant, a charge control agent and the like are included in the polymer particles to produce spherical (spherical or nearly spherical) polymerized toner particles by a polymerization method. After the abrasive particles are fixed to the particles by mechanical impact or thermal treatment, fine silica powder is added to produce a toner.

In this embodiment, the photosensitive member 1 and the developing roller 40 are used.
Since it is a rubbing type, the toner leaks when the resistance value is too low. Therefore, as the toner, a polymerized toner having a high resistance of 10 ⁶ Ωcm or more or an insulating toner is used. Therefore, the resistance of the abrasive particles fixed to the toner particles is 10 ⁶
A resistance value of Ωcm or more is required, and as described later, it is preferably 10 ¹² Ωcm or less, and more preferably 10 ¹⁰ Ωcm or less.

Therefore, as shown in FIG. 3, the volume resistivity of the abrasive particles was measured by using the pressing electrode 21 having the positive electrode 21 at the center and the weight 25 on the upper surface and the negative electrode. A predetermined amount of the abrasive particle sample 26 is placed between the pedestal 28 and the pedestal 28, the current flowing between the samples is measured by the ammeter 23, and the abrasive particle is detected from the current value and the voltage / voltage value of the power supply 24. Calculate the resistance value, 10 ⁶ Ωcm to ^{10 10} Ω
Prepare cm abrasive.

1. Toner Production by Mechanical Impact (1) Weighing and Mixing Stirring Step of Polymerized Toner Particles and Abrasive
Add 5.0 wt% and stir with a Henschel mixer. The stirring conditions are a peripheral speed of 20 to 60 m / sec, a temperature of 15 to 50 ° C (depending on the concentration), and a time of 1 to 15 m.
in. In the treatment here, abrasive particles not larger than the polymerized toner particles are mixed and stirred so that one or two or more toner particles are sprinkled on the surface of the polymerized toner particles.

(2) Surface treatment step of polymerized toner particles For example, mechanical impact (mechanofusion) treatment is performed by a hybridization system manufactured by Horiba.
The conditions are a peripheral speed of 60 to 120 m / sec and a temperature of 10 to 60.
C (depending on the concentration), time 1-10 min. The treatment here is to immobilize the abrasive on the surface of the polymerized toner particles to produce a toner particle combination.

(3) Weighing / mixing stirring step of toner particle combination and silica fine powder 0.3 to 2.0% by weight of silica fine powder is added to the toner particle combination and the same stirring as in the above (1) is performed. Mix and stir under the conditions. In this treatment, silica fine powder, which is not larger than the polymerized toner particles, is added to the toner particles one by one or two.
One or more are electrostatically attached to the surface of the toner particle combination and its vicinity.

2. Toner Production by Thermal Treatment (a) Surface Treatment Step of Polymerized Toner Particles and Abrasive For example, a raw toner powder and an abrasive are simultaneously mixed in an air stream by a surffusion system (Nippon Pneumatic Mfg. Co., Ltd.). Keep the airflow temperature high (100-350 ° C),
The surface of the polymerized toner particles is semi-melted, and 0.5 to 5.0% by weight of the abrasive having the above resistance value is fed into the surface of the polymerized toner particles to adhere to the surface of the polymerized toner particles. When the temperature of the air flow is lowered at the moment of the adhesion, the surface of the semi-molten polymerized toner is cooled and solidified, and the abrasive particles are fixed on the surface of the polymerized toner.
A toner particle combination is produced.

(B) Weighing and Mixing Stirring Step of Toner Particle Binder and Silica Fine Powder As in the above (3), 0.3 to 2.0% by weight of silica fine powder is added to the toner particle binder. Then, the mixture is agitated under the same agitation conditions as the above (1). In this treatment, silica fine powder which is not larger than the polymerized toner particles is electrostatically adhered to the toner particles on the surface of the toner particle combined body and in the vicinity thereof.

As described above, in the polymerized toner, the toner particles are produced by incorporating the colorant, the charge control agent and the like into the polymer particles in the step of polymerizing the polymer from the monomer, so that spherical particles are obtained, Since the electric charge is evenly charged on the spherical particles, point contact with the surface of the photoconductor prevents fogging because there are few contact points for one particle and the image force is small, and high resistance of 10 ⁶ Ωcm or more or insulation Since a photosensitive toner is used, the photoconductor 1 and the developing roller 40
Even if the sliding type is a rubbing type, leakage does not cause image deletion.

The developing roller 40 is the surface layer 1 of the photoreceptor 1.
While contacting c with a nip width of 1 mm or more (preferably 1 to 2 mm) and rotating in the same direction at the contact position, the peripheral speed difference at that position is 1.1 times or more that of the photoconductor 1 (preferably Is a toner layer thickness of 0.3 mg / cm ^{2 to} 0.9 mg /
The speed is set to 1.1 to 6.0 times the cm ² . Further, more preferably, the toner layer thickness is 0.7 mg.
The speed is set to 1.2 to 5.0 times that of / cm ² .

The layer thickness of the toner particles is 0.3 mg / c.
m ^{2 to} 1.0 mg / cm ² , preferably 0.3 mg /
cm ^{2 to} 0.9 mg / cm ² , more preferably 0.4 m
It is set to ^{g / cm 2 ~0.8mg / cm 2} . As the transfer roller 5, a conductive roller is used in order to improve the transfer efficiency onto the recording paper 9, a transfer bias having a polarity opposite to the charging potential of the toner is applied, and the transfer roller 5 is uniformly pressed against the peripheral surface of the photosensitive drum 1. , And is rotatable in synchronization with the drum 1.

The charging unit 8 was uniformly charged on the photoreceptor by a known scorotron charger. In the figure, 81 is a corona discharge line, 82 is a control grid, 8
3 is a discharge bias, and 84 is a charge control bias.

In this embodiment having such a configuration, the charging device 8 has the charging control bias appropriately set to a bias of about 400 V. Therefore, by applying this high voltage discharge bias, After charging the surface potential Vo of the photosensitive drum 1 to the above-mentioned set value, the exposure head 2 exposes a predetermined latent image. After that, + on the developing roller
100V, + 350V is applied to the supply roller to attach the toner image formed by the polymerization method to the latent image of the photoconductor, and transferred to the recording medium (recording paper) 9 inserted between the photoconductor 1 and the transfer roller 5. Let

The recording paper 9 is delivered from a storage (not shown), inserted between the photoconductor 1 and the transfer roller 5, and sent to a fixing step (not shown) after the transfer.

On the other hand, in FIG. 2, the residual toner 49 of the toner not transferred to the recording paper 9 comes into contact with the elastic body 42 of the developing roller 40 again. The developing roller 40 is the photoconductor 1.
Since the peripheral speed is rotating faster than the photoconductor 1 at the contact position with, the residual toner 49 is scraped off by the elastic body 42 of the developing roller 40 as indicated by reference numeral 51, and a new toner 48 is removed. Develop the latent image on the surface of.

The residual toner indicated by reference numeral 51 contains a small amount of photoconductor powder obtained by polishing the surface of the photoconductor 1. That is, the residual toner 51 is scraped off by the developing roller 40 and falls below the developing container 41.
In some cases, the residual toner 52 may be attached to the surface of the developing roller 40 and transferred as shown in FIG. 2 by the supply roller 45 rotating in the opposite direction to the developing roller 40 in the nip area where both rollers influence each other. , Reference numeral 53
As shown in FIG. 3, the toner is dropped and collected below the developing container 41.

On the other hand, the dropped residual toner 53 mixes with the new toner in the developing container 41, but since it is a small amount with respect to the amount of the new toner, it is diluted. Therefore, it is preferable that the residual toner 53 is recirculated in the developing container 41, and is injected into the new toner near the inlet to which the new toner is supplied and agitated.

Here, the cause of the image deletion will be explained. As shown in an enlarged view in FIG. 1A, in the a-Si photosensitive member, the photoconductive layer 1b and the surface layer are formed on the conductive substrate 1a which is generally an aluminum cylinder. The surface layer 1c is formed by stacking 1c, and the surface layer 1c is made of an α-SiC-based inorganic high resistance or insulating material to maintain the surface potential Vo and the latent image potential distribution on the photoconductive layer 1b. .

Therefore, discharge products such as nitrate ions and ammonium ions generated by corona discharge during the image forming process are adsorbed on the surface layer 1c, and these are deposited on the photoconductive layer 1b in a high temperature and high humidity environment. Based on the surface potential Vo and the latent image potential distribution, the latent image charges formed on the surface layer 1c move in the surface direction, and a charge flow, that is, an image flow occurs. Further, it is considered that the continuous printing causes the surface of the photoconductor to be oxidized and deteriorated so that the surface becomes hydrophilic, which is also a factor of image deletion.

Due to this image flow phenomenon, latent image charges flow around the latent image when there is no image flow, and "blurring" of the image occurs.
The phenomenon occurs. On the other hand, in this embodiment, the surface layer of the photoreceptor is formed of an a-Si layer, and the volume resistivity of the developing roller that is in contact with the surface layer can be set to 3 × 10 ⁷ Ωcm or less. By preventing an excessive voltage drop in the roller layer, and synergistically with the low relative dielectric constant of the a-Si photoconductor,
Even if the surface potential of the photoconductor and the developing potential of the developing roller are set low, a sufficient image density can be obtained. Further, since the developing roller is rubbing against the photosensitive member, the discharge product is scraped off, image deletion can be prevented, and good image formation can be performed.

As a result, in this embodiment, the surface potential of the photoconductor is approximately 400 V or less, preferably 300 to 350.
V, or the developing potential of the developing roller can be set to about 150 V or less, preferably 80 to 120 V, whereby the film thickness of the photoconductor can be reduced to 25 μm or less, which is low cost. It is possible to provide an image forming apparatus having the developing device. Further, by adopting such a configuration, it is possible to perform image formation without causing image deletion even in a state where a heater is not built in the substrate that supports the photoconductive layer 1b.

In the embodiment shown in FIG. 2, the developing roller 40 is rubbed against the surface of the surface layer 1c of the photoconductor 1, and the photoconductor 1 is provided with a peripheral speed difference. Since the surface layer is developed, the toner in the developing container 41 can be collected together with the developing in the developing container 41, and the residual toner not used in the developing can be reused. .

Further, the developing roller 40 is the photosensitive member 1.
The effective developing state of the developing roller 40 can be maintained by setting the nip width in contact with the developing roller 40 to 1.5 to 2.0 mm. Then, at the time of the above-described development, the present embodiment
Since the latent image on the photoreceptor 1 is developed while forming a thin layer of toner particles formed by the polymerization method on the developing roller 40, the spherical toner particles are uniformly charged, and Due to point contact with the surface of the photoconductor, there are few contact points for one toner particle, and the image force is small, resulting in'fog '.
There are few phenomena.

As described above in detail, according to the present embodiment, since fog does not occur even when image formation is performed without using a heater, power consumption is greatly reduced, and in addition to the heater and the drum, The thermistor that detects the surface temperature and the electrical components such as the heater control circuit based on the temperature detected by the thermistor reduce the electrical components and simplify the circuit configuration.Because the heater is not used, the warm-up time becomes unnecessary, and the equipment startup time Can be significantly reduced.

[0062]

【Example】

Example (1) An a-Si photosensitive member having a surface layer thickness of 25 μm was prepared, and charging was performed by a scorotron method V0: 350.
V, development is a non-magnetic one-component system, development roller is a conductive roller, diameter is 18 mm, volume specific resistance value: 5 × 10 ⁶ Ω · c
m, surface roughness of 10 microns or less, developing nip of about 1 mm,
Development linear velocity 120 mm / sec (photoconductor linear velocity 60 mm / s
ec), the developing blade has a thickness of 1.3 mm and a resistance value of 1
0 ⁴ Ω · cm or less, supply roll has a diameter of 12 mm, resistance value: 10 ⁴ Ω · cm or less, each bias value is a developing blade 350 V, a supply roller 350 V, and toner is a polymerization method based on a styrene-acrylic material. A toner layer having a mean particle size of 8 μm, an additive amount of 1.0% by weight and an additive amount of silica of 1.0% by weight has a toner layer thickness of 0.7 mg / cm.
^{2 is} used, transfer is a roller type transfer current 20 to 30
Set to microamps.

Under the above condition setting, the resistance of the polishing agent was changed and the measurement was performed. The results are shown in Table 1.

[0064]

[Table 1] From Table 1, it can be seen that when the abrasive resistance is 10 ⁴ Ω · cm, the image density is good at the time of transfer from the photoconductor to the recording medium, but it is separated from the toner at the time of transfer and the abrasive remains on the surface of the photoconductor. Therefore, in the process of collecting the transfer residual toner, the surface of the photoconductor is excessively polished to shorten the life of the photoconductor, and the abrasive collected in the developing device is agitated with the toner in the developing device. The fixed abrasive is stripped off, the amount of nonstandard toner increases, and the life of the toner is adversely affected.

[0065] those of the abrasive resistance 10 ⁴ ~10 ¹³ Ω · cm is not falling off from the toner during transfer, there is no recovery of the abrasive only to the developing device, those of 10 ¹³ Ω · cm, the toner The resistance increases, the toner charge amount increases, and the image density decreases. And abrasive resistance 10 ⁴ to 10 ¹⁰ Ω · cm
In the case of No. 1, the abrasive did not separate from the toner during transfer, and the image density was good.

Example (2) The thickness of the surface layer was 25 μm.
A-Si photoconductor is prepared and charged by scorotron method V
0: 350V, development is non-magnetic single component system, development roller is conductive roller, diameter is 18mm, volume resistivity value: 5x1
0 ⁶ Ω · cm, surface roughness 10 μm or less, developing nip about 1 mm, developing linear velocity 120 mm / sec (photoconductor linear velocity 6
0 mm / sec), the developing blade has a thickness of 1.3 mm,
Resistance value: 10 ⁴ Ω · cm or less, supply roll has a diameter of 12 m
m, resistance value: 10 ⁴ Ω · cm or less, each bias value is the developing blade 350V, the supply roller 350V, and the toner is
A toner layer having a mean particle size of 8 μm and a polishing agent resistance of 10 ⁷ Ω · cm and a silica addition amount of 1.0% by weight is produced by a polymerization method based on a styrene-acrylic material and has a toner layer thickness of 0.7 m.
It is used at g / cm ² and the transfer method is a roller method and the transfer current is 2
It was set to 0-30 microamps.

In the above condition setting, the amount of abrasive added was changed to measure the image forming state. The results are shown in Table 2.

[0068]

[Table 2] From Table 2, when the amount of the polishing agent added is 0.2% by weight, a sufficient polishing / cleaning effect on the surface of the photoreceptor cannot be obtained,
No good image was obtained. When the amount of the polishing agent added was 6.0% by weight, the polishing agent was excessively added, and the polishing agent which was not retained in the toner existed from the beginning. The polishing agent was stirred with the toner in the developing device and fixed from the toner. The abrasives are stripped off, non-standard toner increases, and the life of the toner is adversely affected. When the amount of the abrasive added was 0.3 to 5.0% by weight, almost all of the abrasive was fixed to the toner and a good image was formed.

Example (3) The thickness of the surface layer was 25 μm.
A-Si photoconductor is prepared and charged by scorotron method V
0: 350V, development is non-magnetic single component system, development roller is conductive roller, diameter is 18mm, volume resistivity value: 5x1
0 ⁶ Ω · cm, surface roughness 10 μm or less, developing nip about 1 mm, developing linear velocity 120 mm / sec (photoconductor linear velocity 6
0 mm / sec), the developing blade has a thickness of 1.3 mm,
Resistance value: 10 ⁴ Ω · cm or less, supply roll has a diameter of 12 m
m, resistance value: 10 ⁴ Ω · cm or less, each bias value is the developing blade 350V, the supply roller 350V, and the toner is
A toner layer having a mean particle size of 8 microns produced by a polymerization method based on a styrene-acrylic material, an abrasive resistance of 10 ⁷ Ω · cm, and an abrasive additive amount of 1.0% by weight has a toner layer thickness of 0.7 m.
It is used at g / cm ² and the transfer method is a roller method and the transfer current is 2
It was set to 0-30 microamps.

Under the above condition setting, the running state of 5,000 sheets was tested by changing the amount of silica added and the state of image formation was measured. The results are shown in Table 3.

[0071]

[Table 3] From Table 3, when the amount of silica added is 0.1% by weight, the fluidity is poor, the specific charge (Q / M) stability is deteriorated, the toner charge amount is slowly increased with printing durability, and the image density is lowered. . When the amount of silica added is 3.0% by weight, the fluidity is good, but the amount of charge becomes unstable due to excess silica, the image becomes unstable, and the amount of charge of the toner decreases with printing durability.
Image density decreases. When the amount of silica added was 0.3 to 2.0% by weight, the fluidity of the toner was good, the toner was provided with stable chargeability, and good image formation was performed.

Example (4) The thickness of the surface layer was 25 μm.
A-Si photoconductor is prepared and charged by scorotron method V
0: 350V, development is non-magnetic single component system, development roller is conductive roller, diameter is 18mm, volume resistivity value: 5x1
0 ⁶ Ω · cm, surface roughness 10 μm or less, developing nip about 1 mm, developing linear velocity 120 mm / sec (photoconductor linear velocity 6
0 mm / sec), the developing blade has a thickness of 1.3 mm,
Resistance value: 10 ⁴ Ω · cm or less, supply roll has a diameter of 12 m
m, resistance value: 10 ⁴ Ω · cm or less, each bias value is the developing blade 350V, the supply roller 350V, and the toner is
An average particle size of 8 microns was produced by a polymerization method based on a styrene acrylic material, and an abrasive resistance of 10 ⁷ Ω · cm, an abrasive additive amount of 1.0% by weight, and a charged abrasive of +30 μc / g were added. , + Polar silica 1% by weight was used at a toner layer thickness of 0.7 mg / cm ² ,
The transfer was performed by a roller method with a transfer current of 20 to 30 microamperes. In addition, the regulation of the charge amount and the addition amount of the abrasive is
The ratio of the charge amount before and after the addition of the polishing agent was 1: 1 to 1: 0.
The charge amount and the addition amount were set so as to be in the range of 5.

Under the above-mentioned condition setting, the specific charge (Q / M) of the abrasive and the toner charge amount were changed to measure the image forming state. The results are shown in Table 4.

[0074]

[Table 4] From Table 4, the polarity of the abrasive is the same as that of the toner (Q / M of the abrasive: +50, toner charge: +2).
In the case of 2), the adhesive force with the toner is weak, the toner is dropped from the toner by stirring or the like and stays in the developing device, the abrasive is stirred with the toner in the developing device, and the abrasive fixed from the toner is removed. Stripping and non-standard toner increase, adversely affecting the life of the toner.

Further, the charge polarity of the abrasive is opposite to that of the toner (Q / M of the abrasive: -50, toner charge amount:
+18, Q / M of abrasive: -100, toner charge: +
In the case of 20), in the adhesion with the toner, an electrostatic force is applied in addition to the physical force, and the adhesion force becomes strong.
Therefore, it was possible to prevent the toner from falling off and obtain a good image density.

If the charge polarity of the abrasive is too strong as the opposite polarity of the toner (Q / M of the abrasive: −150, toner charge amount: +2), the charge polarity of the toner itself is reversed. A good image could not be formed. In addition, in the transfer step, the repulsion with the transfer electric field becomes large, a good image cannot be formed, and the abrasive separates from the toner and remains on the surface of the photosensitive member. The surface of the photoreceptor is excessively polished to shorten the life of the photoconductor, and the abrasive collected in the developing device is agitated with the toner in the developing device. Toner increases, which adversely affects the life of the toner.

[0077]

As described above, according to the present invention, a
It is possible to provide an image forming apparatus that can form a clear image without using the image simplification and the'fog 'phenomenon while considering the simplification of the configuration and the safety by using the Si drum.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an embodiment of an image forming apparatus to which the present invention is applied.

FIG. 2 is a configuration diagram showing a structure inside a developing container.

FIG. 3 is a configuration diagram showing a method for measuring a volume resistivity of an abrasive.

[Explanation of symbols]

1 photoconductor drum 2 Exposure head 4 Development unit 40 developing roller 41 developer container 43 Cleaning member 45 Toner supply roller

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hisashi Mutaka Takano, Mino-ken, Tamaki-cho, Mino-ken 704-19 Kyocera Corporation, Mie-Tamagusi Plant (72) Inventor, Keiji Itsukushima, Mie-ken, Mitsu-ken, Mei-gun, Noshino 704-19 Kyocera Co., Ltd. Mie Tamaki Plant (56) References Japanese Patent Laid-Open No. 7-295388 (JP, A) Japanese Patent Publication No. 7-113787 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 9/08 G03G 5/08

Claims (4)

(57) [Claims] 1.The latent image on the amorphous silicon photoconductor
Along with developing, it also collects residual transfer residual toner
In an image forming apparatus equipped with a developing device, The toner particles obtained by the polymerization method are mechanically impacted or thermally
After fixing abrasive particles by treatment, silica fine powder
Using a toner formed by adding The surface layer of the photoconductor gradually hardens from the outermost surface side to the inner side.
The degree is increasing, By a developing roller that develops a latent image by contacting the photoconductor
When the transfer residual toner remaining on the photoconductor is scraped off,
It is possible to polish the surface of the photoconductor with the abrasive particles.
And an image forming apparatus. 2. The abrasive particles have a polarity opposite to that of the toner particles.
Are electrically charged, and the silica fine powder has the same polarity as the toner particles.
The image according to claim 1, wherein the image is electrically charged.
Forming equipment. 3. The abrasive particles have a toner weight of 0.3.
The content of 2 to 5% by weight
Image forming device. 4. The fine silica powder has a toner weight of 0.
The content is 3 to 2% by weight.
The image forming apparatus described.