JPH07160165A - Image forming device - Google Patents

Abstract

(57) [Summary] [Problem] To provide a copying machine suitable for downsizing while obtaining good cleaning performance and image quality even when a small-diameter, spherical toner is used. [Structure] To the toner used in the developing device 3, zinc stearate powder as a friction coefficient reducing agent on the surface of the photoreceptor 1 is externally or internally added, and a non-contact developing method is adopted. Zinc stearate may be applied by the charging roller 21 that is in contact with the photoconductor 1. Further, at a timing when the transfer operation is not performed, the photoconductor 1 may be rotated once or more, and the application may be performed by the transfer roller 41, the transfer belt 45, the intermediate transfer belt 402, or the like that comes into contact with the photoconductor 1. The ratio of the linear velocity of the transfer roller 41 and the like to the linear velocity of the photoconductor 1 during coating is preferably 1.5 to 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile and a printer, and more specifically, a charging device for uniformly charging an image carrier and an optical image on the image carrier. An exposure device that forms a latent image by irradiation, a developing device that visualizes the latent image, a transfer device that transfers the visible image on the image carrier to a transfer material, and a transfer member that uses a cleaning member. And an cleaning device for cleaning the surface of the image carrier.

[0002]

2. Description of the Related Art Conventionally, as a cleaning member in a cleaning device of this type of image forming apparatus, a cleaning blade made of an elastic member such as polyurethane rubber, a fur brush, a magnetic brush or the like can be used. Among these, the cleaning blade is widely used because of its simple structure, small size, and advantageous cost.

By the way, recently, in order to improve the image quality, the diameter and sphere of the toner have been reduced. When such a small-diameter, spherical toner is used, the fixing force of the toner to the image carrier becomes large, and cleaning failure may occur. In particular, in the image forming apparatus provided with the cleaning device using the cleaning blade, even if the tip of the blade is slightly turned up or vibrated, the cleaning cannot be performed by scraping off the toner, which may result in defective cleaning.

In order to solve such a problem of defective cleaning, Japanese Patent Laid-Open No. 1-229281 discloses that some toner is attached to a non-image portion on an image carrier,
Reversing (turning) the cleaning blade by reducing the friction coefficient between the cleaning blade and the image carrier
It has been proposed to prevent the above and improve the cleaning performance.

Further, in JP-A-57-111576, a cleaning aid as a friction coefficient lowering agent for reducing the friction coefficient between an image carrier and a cleaning blade, for example, a fatty acid metal salt such as zinc stearate is cleaned. It has been proposed that the cleaning performance is improved by adding an auxiliary agent to the developer and further applying a cleaning auxiliary agent onto the image carrier with a brush.

Further, Japanese Patent Laid-Open No. 60-225870,
JP-A-2-106780, JP-A-3-26947
According to Japanese Patent Laid-Open No. 8, the cleaning aid and the lubricant as the friction coefficient lowering agent are applied on the image bearing member, or the end of the cleaning blade is formed of a material having a small friction coefficient, so that the cleaning blade is curled or chattering occurs. It has been proposed to prevent the occurrence of cleaning failure and prevent the occurrence of cleaning failure.

[0007]

However, in the image forming apparatus proposed in Japanese Unexamined Patent Publication No. 1-229281, the toner is attached to the non-image portion on the image carrier, so that the number of copies increases. Accordingly, there is a problem that the consumption amount of toner that does not directly contribute to image formation increases. In an extreme case, the toner will be exhausted just by performing idling operation without performing the copying operation.

Further, the above-mentioned JP-A-57-111576, JP-A-60-225870 and JP-A-2-10.
In the image forming apparatus proposed in Japanese Laid-Open Patent Publication No. 6780 and Japanese Laid-Open Patent Publication No. 3-269478, since the surface of the image bearing member becomes slippery by applying the above friction coefficient lowering agent, when contact development is adopted, There is a problem that uneven development occurs due to rubbing in the developing section, and image deterioration such as blurring and white spots easily occurs. In particular, in the case of contact development, it is common to make the linear velocity of the developing roller, which is the developer bearing member, higher than the linear velocity of the image bearing member in order to prevent background stains, and the development unevenness easily occurs. .

In particular, recently, the downsizing of the apparatus has become mainstream, and it has become difficult to secure a space for disposing a device for applying a friction coefficient lowering agent by a fur brush or a roller in addition to a cleaning member such as a blade. .

The present invention has been made in view of the above problems, and an object thereof is to obtain good cleaning performance and high image quality even when a small-diameter, spherical developer is used. An object is to provide an image forming apparatus suitable for downsizing.

[0011]

In order to achieve the above object, the invention of claim 1 provides a charging device for uniformly charging an image carrier, and irradiating a light image on the image carrier. An exposure device that forms a latent image by means of a developing device, a developing device that visualizes the latent image, a transfer device that transfers the visible image on the image carrier to a transfer material, and a surface of the image carrier after the transfer is cleaned. An image forming apparatus including a cleaning device for cleaning with a member is provided with an application unit that applies a friction coefficient lowering agent that lowers a friction coefficient of a surface of the image carrier to the developing device. Is configured to visualize the latent image without contacting the image carrier. Here, as the friction coefficient lowering agent, a fatty acid metal salt such as zinc stearate or the like is effective. Further, as the coating means, for example, the friction coefficient lowering agent may be added internally or externally to the developer used in the developing device. A cleaning blade, a fur brush, a magnetic brush, or the like can be used as the cleaning member, and the cleaning blade is advantageous in terms of downsizing and cost reduction.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, which is provided with a charging device having a charging member that comes into contact with the surface of the image carrier, the charging member is used as the coating member. It is characterized by using a member. As the charging member, for example, a cylindrical charging roller having a surface portion formed of an elastic body having a medium resistance can be used.

According to a third aspect of the present invention, in the image forming apparatus of the first aspect, the image forming apparatus includes a transfer device having a transfer member that comes into contact with the surface of the image carrier. It is characterized by using a member. As the transfer member, for example, a cylindrical transfer roller or a transfer belt suspended around a plurality of support rollers can be used.

According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, the image carrier is rotated once or more at a timing when the transfer operation by the transfer device is not performed, and the transfer member is rotated. It is characterized in that control means for controlling the coating means is provided so as to coat the friction coefficient lowering agent on the surface of the image carrier. For example, at the time of heat-up after turning on the main switch of the apparatus, before the start of the image forming operation, or after the end of the image forming operation, the friction coefficient lowering agent is controlled to be applied.

According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect, the image carrier is provided at a timing when the transfer material is not supplied to the transfer device during continuous image formation on the plurality of transfer materials. Is rotated one or more times, and control means for controlling the coating means is provided so as to coat the friction coefficient lowering agent on the surface of the image carrier using the transfer member.

Further, the invention of claim 6 is based on claims 3 to 5.
In the image forming apparatus, the linear velocity ratio of the surface of the transfer member to the surface of the image carrier at the time of applying the friction coefficient lowering agent is set to 1.5 to 3.

[0017]

According to the present invention, the friction coefficient on the image bearing member can be lowered by applying the friction coefficient lowering agent to the surface of the image bearing member by the coating means, and in particular, the cleaning member. When a cleaning blade is used for the blade, it is possible to prevent the blade from curling or chattering. Then, by performing the development in a non-contact manner, it becomes possible to suppress the occurrence of development unevenness due to the rubbing on the surface of the image bearing member which has become slippery by the friction coefficient lowering agent.

According to the second aspect of the present invention, a charging member that contacts the surface of the image carrier of the charging device is used as a member for applying the friction coefficient lowering agent in the applying means. This eliminates the need to separately provide a coating member in the coating means.

According to the third aspect of the present invention, the transfer member contacting the surface of the image carrier of the transfer device is used as the member for applying the friction coefficient lowering agent in the applying means. This eliminates the need to separately provide a coating member in the coating means.

According to another aspect of the invention, the image carrier is rotated by one or more revolutions at a timing when the transfer operation by the transfer device is not performed by the control means, and the image carrier is transferred by using the transfer member. By controlling the application means so as to apply the friction coefficient lowering agent to the surface of the body, it is possible to reliably apply the friction coefficient lowering agent to the surface of the image bearing member without affecting the image forming operation. Become.

According to a fifth aspect of the invention, the control means rotates the image carrier one or more revolutions at a timing when the transfer material is not supplied to the transfer device during continuous image formation on the plurality of transfer materials. Then, by controlling the coating means so as to coat the friction coefficient lowering agent on the surface of the image carrier by using the transfer member, the friction on the surface of the image carrier can be achieved without affecting the transfer operation. The coefficient lowering agent can be reliably applied.

In the invention of claim 6, the linear velocity ratio of the surface of the transfer member to the surface of the image carrier at the time of application of the friction coefficient lowering agent is set to 1.5 to 3.
A predetermined amount of the friction coefficient lowering agent can be surely applied to the surface of the image carrier.

[0023]

Embodiments Embodiments in which the present invention is applied to an electrophotographic copying machine (hereinafter referred to as a copying machine) which is an image forming apparatus will be described below. [Embodiment 1] FIG. 1 is a front view showing a schematic configuration of a copying machine according to Embodiment 1 of the present invention. The photoconductor drum having the photoconductor 1 as an image carrier on its surface is rotationally driven in the clockwise direction of the arrow at a predetermined linear velocity (for example, 120 mm / sec). The photoconductor 1 is an example of the configuration of the image carrier, and a belt-shaped image carrier can be used instead of the photoconductor 1 on the photoconductor drum. Around the photosensitive drum, a charging device 2 using a charging charger, an exposure device (not shown), a developing device 3, a transfer device 4 using a transfer charger, a discharging device 5 using a discharging charger, and a cleaning device for performing an electrophotographic process. The device 6 and the like are provided.

FIG. 2 is a front view showing a schematic structure of the developing device 3. As a developing method, the applicant of the present invention disclosed in Japanese Patent Laid-Open No. 4-1
27177, the non-magnetic one-component developer (hereinafter,
A developing method using a toner) is adopted. The developing device 3 includes a casing 31 having an opening facing the surface of the photoconductor 1 and a part of the casing 31 is exposed from the opening and is rotated counterclockwise at a predetermined linear velocity (for example, 132 to 144 mm / sec). A developing roller 32 as a developer carrying member, a toner supplying roller 33 as a developer supplying member which is rotationally driven in the counterclockwise direction of the arrow while being pressed against the right side portion of the developing roller 32, and a casing 31 The rotation of the developing roller 32 and the agitator 34 that stirs the toner in the hopper portion while supplying the toner 7 contained in the hopper portion as the developer storing means configured on the right side of the A layer thickness leveling plate 35 as a developer regulating member for leveling the thickness of the toner layer on the developing roller 32 conveyed to the developing area A, which is the portion facing the photoconductor 1.
And have. Here, the charging polarity of the toner 7 is positive.

3A to 3C are plan views of a part of the surface of the developing roller 32 used in the first embodiment, a sectional view of the roller 32, and the surface of the roller 32, respectively. The explanatory view of a minute closed electric field is shown. This developing roller 3
2 is a resin dispersion type developing roller, which is a metal roller 320.
Dielectric particles 322 are dispersed in the upper conductive resin 321. Dielectric particles 322 of this developing roller 32
Has a particle size (d) of 50 μm or more, and a sufficient minute closed electric field can be obtained by charging the dielectric particles 322. The upper limit of the particle diameter (d) of the dielectric particles 322 is 200 μm as a size on a plane due to restrictions from the image and the roller method.
The extent is limited. When the dielectric particles 322 become large, the spatial distribution of the gradient force due to the minute closed electric field on the developing roller 32 becomes coarse, and the toner adheres sparsely, resulting in an uneven image. In addition, the dielectric particles 32
The dimension of 2 in the depth direction is limited to about 100 μm due to the limitation of the roller construction method.

As shown in FIG. 1, the developing roller 32 opposes the surface of the photosensitive member 1 in the developing area A with a predetermined gap to perform non-contact developing. The surface of the developing roller 32 that has passed the developing area A reaches a contact portion B with the toner supply roller 33. Further, a DC voltage or the like is applied to the developing roller 32 by a bias power source (not shown).

The toner supply roller 33 is provided with a sponge layer which is an elastic foam on a core metal, and a large number of holes are opened on the surface so that the toner can be retained at least inside the surface of the sponge layer. is doing. By using a sponge layer having an apparent density of 0.1 g / cm ³ or less, a cell number of 100 cells / inch or less, and an electric resistance of 10 ¹⁰ Ωcm or less, it is possible to satisfactorily hold a sufficient amount of toner. . As a material for the sponge layer, for example, urethane sponge can be used. Further, the toner supply roller 33 is supported, for example, at a position where it comes into contact with the surface of the developing roller 32 by a predetermined amount and is pressed against it, and is rotated so that the surface moves in the direction opposite to the surface of the developing roller 32 at the contact portion with the developing roller 32. Driven. The linear velocity of the toner supply roller 33 is about 0.
It is set to 5 to 1.5 times. Further, by the bias power source, the core metal of the toner supply roller 33 is also connected to the developing roller 3
A voltage similar to that applied to 2 is applied.

The agitator 34 supplies the toner 7 contained in the hopper portion to the surface of the toner supply roller 33 and agitates the toner 7 contained therein. However, due to the shape of the hopper portion, the fluidity of the toner 7 and its own weight, If the toner can be supplied to the surface of the toner supply roller 33, it may be omitted.

The layer-thickness leveling plate 35 is, for example, 10-2.
It is arranged so as to come into contact with the developing roller 32 with a light contact pressure of about 0 g / cm.

In the cleaning device 6, a cleaning blade 61 as a cleaning member is brought into contact with the surface of the photoconductor 1. In the first embodiment, the cleaning blade 61 is arranged so that its contact direction is opposite to the moving direction of the surface of the photoconductor 1.

In the first embodiment, the cleaning blade 6 is increased due to the increase in the adhesion of the toner 7 to the photoconductor 1.
In order to prevent cleaning failure due to curling of the tip of No. 1 and the like, as the toner 7 used in the developing device 3, a toner to which a friction coefficient lowering agent is added is used. Specifically, JP-A-57
As disclosed in Japanese Patent Application Laid-Open No. -111576, 0.5 wt% zinc stearate powder (average particle size 1 μm) as a friction coefficient lowering agent was externally added. As the friction coefficient lowering agent, in addition to zinc stearate, many materials such as fatty acid metal salts having the same effect can be used.

As described above, in the structure of the first embodiment, the toner 7 contained in the hopper is supplied to the surface of the toner supply roller 33 by the agitator 34. The toner 7 supplied to the toner supply roller 33 is carried on the surface of the sponge layer or in the holes, and is directed toward the contact portion B between the toner supply roller 33 and the developing roller 32 by the counterclockwise rotation of the toner supply roller 33. Be transported.

Then, due to the friction between the developing roller 32, the toner 7 and the toner supplying roller 33, the dielectric particles 322 on the surface of the developing roller 32 are charged with a polarity opposite to the desired toner charging polarity (photoreceptor charge in normal development). The same polarity is charged, and in the reversal development, the polarity is opposite to that of the photoconductor charge). In the first embodiment, the regular development using the toner 7 that is positively charged is adopted, and the dielectric particles 3 are used.
22 is negatively charged. Then, the dielectric particles 32
A large number of minute closed electric fields (E) are formed between 2 and the grounded conductive resin 321.

On the other hand, the toner 7 carried on the toner supply roller 33 is slid between the developing roller 32 and the toner supply roller 33, and most of it has a desired polarity (in the normal development, the polarity is opposite to the photoconductor charge, In reversal development, it has the same polarity as the photoconductor charge). In the first embodiment,
The toner 7 is positively charged.

The charged toner 7 on the toner supply roller 33 is electrostatically attracted by the minute closed electric field (E) formed on the developing roller 32, and the developing roller 32
After adhering to the surface in a sufficient amount, it leaves the contact portion B. The toner layer on the developing roller 32 that has passed through the contact portion B is rubbed uniformly by the layer thickness leveling plate 35, which is in light contact with the developing roller 32, to form a uniform thin layer, and a stable multi-layer. It becomes a thin layer and is conveyed to the developing area A by the rotation of the developing roller 32. In the first embodiment, the developing roller 3
The amount of adhesion on No. ² was 0.8 to 1.5 mg / cm ² (measured by tape transfer method), and the amount of charge was 10 to 20 μc / g (measured by suction method).

In the developing area A, the surface of the developing roller 32 to which the optimum developing bias is applied by the non-contact developing method and the surface of the photosensitive member 1 have a predetermined linear velocity ratio Rd (first embodiment 1).
In the case of, Rd = 132/120 to 144/120 =
1.1 to 1.2) to move the photoconductor 1 and the developing roller 32.
The toner 7 is caused to fly to the surface of the photoconductor 1 by the electric field between and, and development is performed.

As described above, by forming a stable multi-layered toner layer on the developing roller 32 and developing at the linear velocity ratio Rd, the linear velocity ratio Rd is set to 2 to 4 on the developing roller. The uniformity of solid images, reproducibility of fine lines, and high speed are improved as compared with the conventional one in which toner is carried in a single layer.

The friction coefficient lowering agent externally added to the toner 7 adheres to the surface of the photoconductor 1 together with the toner 7 in the developing process.

The toner image formed on the photosensitive member 1 is transferred by the transfer device 4 onto the transfer paper 8 as a transfer material.
In the present Example 1, a stable image having an image density of 1.3 to 1.4 with no background stain on the transfer paper 8 was obtained. After the transfer, the photoconductor 1 on which the toner remains is further rotated and the charge is removed by the charge removing device 5, and the residual toner on the photoconductor 1 is cleaned by the cleaning blade 61 of the cleaning device 6.

As described above, according to the first embodiment, zinc stearate powder can be applied to the surface of the photoreceptor 1 by externally adding the zinc stearate powder as the friction coefficient lowering agent to the toner 7. By using this zinc stearate, the friction coefficient of the surface of the photoconductor 1 can be reduced, and the occurrence of curling or chattering at the tip of the cleaning blade 61 can be suppressed. Therefore, good cleaning performance can be obtained. (Hereafter, margin)

By using the non-contact development in the developing step, the occurrence of uneven development due to the friction between the surface of the photosensitive member 1 and the developing roller 32, which is easily slipped by the friction coefficient lowering agent, is suppressed, and the image is deteriorated. I was able to get an image without.

As described above, according to the first embodiment, good cleaning performance can be obtained, and high image quality can be obtained due to good developing characteristics.

[Embodiment 2] FIG. 4 is a schematic block diagram of a copying machine according to another embodiment 2 of the present invention. In the first embodiment, the friction coefficient lowering agent is externally added to the toner 7, but instead of this, in the second embodiment, a coating member for applying the friction coefficient lowering agent to the surface of the photoconductor 1 is provided in the cleaning device 6. It is provided. The toner 7 has a volume average particle size of 7 to 10 μm.
A toner having a particle size distribution of 5 to 20 μm was used. Since other configurations are common to those of the copying machine of the first embodiment, common members, devices and the like are designated by the same reference numerals, and detailed description thereof will be omitted.

In the cleaning device 6 of the second embodiment, an application member for applying a friction coefficient lowering agent to the surface of the photoconductor 1 is provided upstream of the contact portion of the cleaning blade 61 in the rotation direction of the photoconductor 1. It is provided. This coating means rubs the block-shaped zinc stearate 9 as a friction coefficient reducing agent attached to the inner surface of the lower wall of the casing 60 of the cleaning device 6, and the surface of the zinc stearate 9 and the surface of the photoconductor 1. Meanwhile, the fur brush 62 and the like are driven to rotate in the direction of the arrow.

According to the second embodiment, by rotating the fur brush 62 in the direction of the arrow, part of the block-shaped zinc stearate 9 is applied to the surface of the photoconductor 1.
As a result, it was possible to obtain the same effect as that of the first embodiment.

[Embodiment 3] A copying machine according to another embodiment 3 of the present invention has the same construction as that of the copying machine shown in FIG. 4, except that a polymerized toner is used as the toner 7 in order to obtain high image quality. This is different from the second embodiment. Specifically, the applicant of the present invention has disclosed that
A dispersion-polymerized toner having the formulation presented in -137372 was used. Here, a polymerized toner having a volume average particle diameter of 10 μm or less is preferable in that the toner is less likely to aggregate and higher image quality can be obtained.

According to the third embodiment, by rotating the fur brush 62 in the direction of the arrow, a part of the block-shaped zinc stearate 9 is applied to the surface of the photoconductor 1 and the surface of the photoconductor 1 is rubbed. Since the coefficient is reduced, even when conditions are bad for cleaning with a blade, such as when using a polymerized toner whose particle size is as small as around 5 μm and whose shape is almost spherical, It was possible to obtain good cleaning performance by suppressing the occurrence of curling of the tip of the cleaning blade 61.

OPC is used as the photosensitive member 1, and 0 to -1 kV with respect to the latent image potential of -500 to -700 V.
Good development characteristics were obtained by performing non-contact development using a development bias voltage of a pulse having a repetition frequency of 1.5 to 2.0 kHz.

[Embodiment 4] FIG. 5 shows a schematic configuration diagram of a copying machine according to another embodiment 4 of the present invention. In the first embodiment, the friction coefficient lowering agent is externally added to the toner, but instead of this, in the fourth embodiment, the charging device is used as a coating member of the coating means for coating the surface of the photoconductor 1 with the friction coefficient lowering agent. Is used. Further, as the toner 7, the applicant of the present invention has disclosed in
A dispersion-polymerized toner having the formulation presented in 137372, having an average particle size of about 5 μm and a particle size distribution of 4 to 7 μm was used. When this toner 7 is used, the developing roller 3
It was possible to obtain an adhesion amount of 0.8 to 1.5 mg / cm ² (measured value by the tape transfer method) and an electrification amount of 20 to 30 μc / g (measured value by the suction method). Since other configurations are common to those of the copying machine of the first embodiment, common members, devices and the like are designated by the same reference numerals, and detailed description thereof will be omitted.

The charging device according to the fourth embodiment includes a cylindrical charging roller 21 formed of an elastic body having a medium resistance as a charging member that contacts the surface of the photosensitive member 1. A DC voltage of 2 to 3 kV is applied to the charging roller 21 by the charging power source 22. Block-shaped zinc stearate 9 and zinc stearate 9 arranged above the charging roller 21 so as to contact the surface of the roller 21 are pressed against the surface of the charging roller 21 in the arrow direction. A pressing means 23 is provided. For example, as shown in FIG. 5, the pressing means 23 can be composed of a spring 23b as an urging member having one end fixed to the zinc stearate 9 and the other end fixed to the fixed end member 23a.

As described above, according to the fourth embodiment, the charging roller 21 rotating in the direction of the arrow rubs the zinc stearate 9 pressed against the surface, and temporarily holds the zinc stearate 9 on the surface. Then, when further rotated, zinc stearate 9 is applied to the surface of the photoconductor 1 at the contact portion with the photoconductor 1. As a result, the coefficient of friction of the surface of the photoconductor 1 is lowered, so that the cleaning blade 61 is prevented from being turned over, and good cleaning performance can be obtained.

By using non-contact development in the developing step, the occurrence of uneven development due to the friction between the surface of the photosensitive member 1 and the developing roller 32, which is easily slipped by the friction coefficient lowering agent, is suppressed, and blurring and white spots occur. It was possible to obtain an image without image deterioration such as.

As described above, according to the fourth embodiment, good cleaning performance can be obtained, and high image quality can be obtained due to good developing characteristics.

In particular, according to the fourth embodiment, by using the charging device 2 as the coating member of the coating means, it is not necessary to provide a separate device such as a fur brush as the coating member, and therefore, it can be saved. It is advantageous in terms of space saving and cost reduction.

In the fourth embodiment, by changing the linear velocity ratio of the surface of the charging roller 21 to the surface of the photoconductor 1, the amount of zinc stearate 9 applied to the surface of the photoconductor 1 can be controlled. . According to the experiments by the inventors,
Under the conditions that the pressing force of the spring 23b was set to 30 gf-cm and the linear velocity ratio was set to 1.2 to 2.0, zinc stearate having a thickness of 10 to 50 μm could be applied to the surface of the photoconductor 1. Therefore, at least when zinc stearate is applied, it is preferable to control the rotation speed of the charging roller 21 so that the linear velocity ratio becomes 1.2 to 2.0.

[Embodiment 5] FIG. 6 is a schematic structural diagram of a copying machine according to another embodiment 5 of the present invention. This copying machine is different from the copying machine of the fourth embodiment in that the charging device as the coating means is configured to supply the fine powder of zinc stearate onto the charging roller 21. Since other configurations are common to those of the copying machine of the fourth embodiment, common members, devices and the like are designated by the same reference numerals, and detailed description thereof will be omitted.

In the charging device of the fifth embodiment, the charging roller 2
A container 25 sealed by two rollers 24 and an upper lid 25a is provided above the container 1, and the container 25 is filled with zinc stearate fine powder.

According to the fifth embodiment, by rotating the charging roller 21 having fine zinc stearate powder adhered to the surface thereof in the direction of the arrow, the surface of the photosensitive member 1 is steared at the contact portion with the photosensitive member 1. Zinc acid is thinly coated. As a result, the same effect as in Example 4 above could be obtained.

[Sixth Embodiment] FIG. 7 is a schematic diagram of a copying machine according to a sixth embodiment of the present invention. In this copying machine, a charging roller as a coating means is configured to supply zinc stearate onto the charging roller 21 by using a coating roller in which fine powder of zinc stearate is formed in a cylindrical shape. , Which is different from the copying machine of the fourth embodiment. Since other configurations are common to those of the copying machine of the fourth embodiment, common members, devices and the like are designated by the same reference numerals, and detailed description thereof will be omitted.

In the charging device of the sixth embodiment, the charging roller 2
1, a coating roller 26 formed by solidifying fine powder of zinc stearate on a shaft 26a having a small diameter is provided.
The coating roller 26 is configured to come into contact with the surface of the charging roller 21 and follow the rotation of the charging roller 21. The coating roller 26 may be driven independently of the charging roller 21.

According to the sixth embodiment, as the charging roller 21 rotates in the direction of the arrow, the coating roller 26 rotates and zinc stearate is supplied onto the charging roller 21. Then, zinc stearate is thinly coated on the surface of the photoconductor 1 at the contact portion with the photoconductor 1. As a result, the same effect as in Example 4 above could be obtained.

The coating amount of zinc stearate on the photosensitive member 1 is the same as the coating roller 26 for the surface of the charging roller 21.
The optimum value can be controlled by changing the linear velocity ratio on the surface of the.

[Embodiment 7] FIG. 8 shows a schematic block diagram of a copying machine according to another embodiment 7 of the present invention. In the first embodiment, the friction coefficient lowering agent is externally added to the toner, but instead of this, in the seventh embodiment, a transfer device is used as a coating means for coating the surface of the photoconductor 1 with the friction coefficient lowering agent. . Also,
As the toner 7, the applicant of the present invention has disclosed in Japanese Patent Application Laid-Open No. 4-137372.
The dispersion-polymerized toner having the formulation presented in 1., having an average particle size of about 5 μm and a particle size distribution of 4 to 7 μm was used. When this toner is used, the adhesion amount on the developing roller 32 is 0.8 to 1.5 mg / cm ² (measured value by the tape transfer method), and the charge amount is 20 to 30 μc / g (measurement value by the suction method). I was able to get it. Since other configurations are common to those of the copying machine of the first embodiment, common members, devices and the like are designated by the same reference numerals, and detailed description thereof will be omitted.

The transfer device 4 of Example 7 is a transfer member that comes into contact with the surface of the photoconductor 1 and has a medium hardness of fluorine-based or silicone-based resin on the surface of the shaft having JIS hardness of 50 to 80 degrees. A cylindrical transfer roller 41 coated with an elastic body is provided. A direct current voltage of 2 to 3 kV is applied to the transfer roller 41 by the transfer power supply 42.

Below the transfer roller 41, a block-shaped zinc stearate 9 arranged so as to contact the surface of the roller 41, and zinc stearate 9 in the direction of the arrow with respect to the surface of the transfer roller 41. A pressing means is provided for pressing against. The pressing means may be composed of a plate spring-shaped pressing member 43 as shown in FIG. 8, for example.

As described above, according to the seventh embodiment, the transfer roller 41 rotating in the direction of the arrow rubs the zinc stearate 9 pressed against the surface thereof, and a part of this zinc stearate is applied to the surface. Supplied. Then, when further rotated, zinc stearate is applied to the surface of the photoconductor 1 at the contact portion with the photoconductor 1. As a result, the coefficient of friction of the surface of the photoconductor 1 is lowered, so that the cleaning blade 61 is prevented from being turned over, and good cleaning performance can be obtained.

By using non-contact development in the developing step, the occurrence of uneven development due to the friction between the surface of the photosensitive member 1 and the developing roller 32, which is easily slipped by the friction coefficient lowering agent, is suppressed, and blurring and white spots are prevented. It was possible to obtain an image without image deterioration such as.

As described above, according to the seventh embodiment, good cleaning performance can be obtained, and high image quality can be obtained due to good developing characteristics.

According to the seventh embodiment, in particular, by using the transfer device 4 as the coating member of the coating means, it is not necessary to provide another device such as a fur brush as the coating member. It is advantageous in terms of space saving and cost reduction.

In the seventh embodiment, zinc stearate cannot be applied at the time of transfer. Therefore, the application timing is the time of heat-up after the main switch of the apparatus is turned on, the interval of passage of the transfer paper 8 or the end of copying. It is preferable to set the time and the like, and rotate the photoreceptor 1 or more times at that timing so that zinc stearate is applied to the entire surface of the photoreceptor 1. The control unit of the apparatus main body can be used as the control means for controlling the application timing and the like.

By changing the linear velocity ratio of the surface of the transfer roller 41 to the surface of the photoconductor 1, the amount of zinc stearate applied to the surface of the photoconductor 1 can be controlled. According to experiments conducted by the present inventors, a stearin film having a thickness of 10 to 50 μm is formed on the surface of the photoconductor 1 under the condition that the pressing force of the pressing member 43 is set to 30 gf-cm and the linear velocity ratio is set to 1.5 to 3.0. The zinc acid could be applied. Therefore, at least when the zinc stearate is applied, the linear velocity ratio is 1.
It is preferable to control the rotation speed of the transfer roller 41 so as to be 5 to 3.0.

[Embodiment 8] FIG. 9 shows a schematic configuration of a copying machine according to another embodiment 8 of the present invention. This copying machine uses a transfer belt instead of the transfer roller 41 as a transfer member of the transfer device 4, and transfers zinc stearate by using a coating roller in which fine powder of zinc stearate is formed in a cylindrical shape. It is different from the copying machine of the above-mentioned Embodiment 7 in that it is supplied on a belt. Since other configurations are common to those of the copying machine of the seventh embodiment, common members, devices and the like are designated by the same reference numerals, and detailed description thereof will be omitted.

In the transfer device of the eighth embodiment, a transfer belt 45 is used as a transfer member, which is hung between two small-diameter support rollers 44 and rotationally driven in the arrow direction. The transfer belt 45 is arranged so as to sandwich the transfer paper 8 and come into contact with the photoconductor 1. The support roller 44 includes
If necessary, a transfer bias voltage can be applied by the transfer power supply 42. The transfer belt 45
May be suspended on more than two support rollers.

As the material of the transfer belt 45, a medium resistance material (about 10 ⁸ to 10 ¹² Ωcm) having excellent releasability is preferable. This is because if the electric resistance is too high, electric charges are likely to be accumulated on the belt 45, and conversely if the electric resistance is too low, electric charges in the bias applying section are likely to leak (transfer leak) through the belt 45. Examples of materials for the intermediate transfer belt 45 include polycarbonate and ETFE (tetrafluoroethylene-ethylene copolymer). In addition, PFA (tetrafluoroethylene-perfluoroalkyl ether copolymer), FE on a nickel belt
A material coated with a fluorine-based material such as P (tetrafluoroethylene-hexanefluoropropylene copolymer) can also be used.

Further, below the charging belt 45, there is provided a coating roller 46 formed by solidifying fine powder of zinc stearate on a shaft 46a having a small diameter. This coating roller 46
Is configured to come into contact with the surface of the transfer belt 45 and follow the rotation of the transfer belt 45. The coating roller 46 may be driven independently of the transfer belt 45.

As described above, according to the eighth embodiment, the transfer belt 4
As 5 rotates in the direction of the arrow, the coating roller 26 rotates and zinc stearate is supplied onto the transfer belt 45. Then, zinc stearate is thinly coated on the surface of the photoconductor 1 at the contact portion with the photoconductor 1. As a result, it was possible to obtain the same effects as those of Example 7 above.

[Embodiment 9] FIG. 10 is a schematic structural diagram of a copying machine according to another embodiment 9 of the present invention. This copier is
It differs from the copying machine of Example 7 in that an intermediate transfer member is provided between the photoconductor 1 and the transfer roller 41, and zinc stearate is supplied to the intermediate transfer member. Since other configurations are common to those of the copying machine of the seventh embodiment, common members, devices and the like are designated by the same reference numerals, and detailed description thereof will be omitted.

In the transfer device of the ninth embodiment, as the intermediate transfer member, the intermediate transfer belt 402 is hung between the two support rollers 401a and 401b and driven to rotate in the arrow direction.
Is used. The intermediate transfer belt 402 is arranged so as to come into contact with the photoconductor 1 on the side of one support roller 401a. Further, as the material of the intermediate transfer belt 402, the same material as the transfer belt 45 of the above-described Example 8 was used. The intermediate transfer belt 402 may be suspended on three or more support rollers.

A predetermined intermediate transfer bias voltage (for example, 2 to 3 kV) is applied to the supporting roller 401a of the intermediate transfer belt 402 on the side of the photoconductor 1 by the intermediate transfer power source 4032.
DC voltage) is applied. In addition, the intermediate transfer belt 402
A cleaning device 404 is provided for cleaning the surface of the sheet with a blade 404a. This cleaning device 4
04 is provided as needed.

On the right side of the support roller 401b, a block of zinc stearate 9 arranged so as to contact the surface of the intermediate transfer belt 402, and zinc stearate 9 on the surface of the intermediate transfer belt 402. A pressing means for pressing in the direction of the arrow is provided. This pressing means may be composed of a plate spring-shaped pressing member 406 as shown in FIG. 10, for example.

In the transfer process of the copying machine having the above structure, first,
The toner image on the photoconductor 1 is transferred to the intermediate transfer belt 4 by the intermediate transfer bias voltage applied from the intermediate transfer power source 403.
02 (first transfer step). Next, the toner image on the intermediate transfer belt 402 is transferred onto the transfer paper 8 by the transfer roller 41 (second transfer step).

As described above, according to the ninth embodiment, the intermediate transfer belt 402 rotating in the direction of the arrow rubs the zinc stearate 9 pressed against its surface, and a part of this zinc stearate is on the surface. Is supplied to. Then, when further rotated, zinc stearate is applied to the surface of the photoconductor 1 at the contact portion with the photoconductor 1. As a result, it was possible to obtain the same effects as those of Example 7 above.

In the ninth embodiment as well, since zinc stearate cannot be applied at the time of transfer, the application timing is such that heat is applied after the main switch of the apparatus is turned on, during the passage of the transfer paper 8 or during copying. It is preferable to set at the end or the like, and control so that the photoreceptor 1 is rotated once or more at that timing to apply zinc stearate to the entire surface of the photoreceptor 1.

By changing the linear velocity ratio of the surface of the intermediate transfer belt 402 to the surface of the photoconductor 1, the amount of zinc stearate applied to the surface of the photoconductor 1 can be controlled.

Although the transfer roller 41 is used in the ninth embodiment, the transfer charger of the first embodiment, the transfer belt 45 of the eighth embodiment, or the like may be used instead of the transfer roller 41. The intermediate transfer belt 4 is used as the intermediate transfer member.
Instead of 02, an intermediate transfer roller may be used.

Although each of the above-mentioned embodiments shows an example in the case of regular development using a negatively charged photosensitive member and a positively charged toner, the present invention is limited to the charged polarities of the photosensitive member and the toner. Image forming apparatus of other general electrophotographic type such as a copying machine adopting a developing method using a two-component developer in addition to the regular developing method and the reversal developing method. The same effect can be obtained. (Hereafter, margin)

Further, in each of the above-described embodiments, a non-magnetic single component using the developing roller 32 whose surface is composed of the conductive portion made of the conductive resin 321 and the dielectric portion made of the dielectric particles 322 in order to increase the adhered toner. Developing device 3 using system developer
However, the present invention is not limited to the copying machine provided with the developing device 3 of this kind, and is provided with a developing device using a magnetic one-component developer, for example. The same can be applied to an image forming apparatus such as a copying machine, and a copying machine including a developing roller not provided with a conductor portion and a dielectric portion on its surface portion, a developing roller having a magnet inside, and the like. It can be applied to an image forming apparatus, and the same effect can be obtained.

In each of the above embodiments, the blade 61 is arranged so that the contact direction of the tip of the cleaning blade 61 is opposite to the moving direction of the surface of the photoconductor 1, but the present invention is not limited to this. The arrangement is not limited to this arrangement. For example, the blade 61 may be arranged so as to contact the surface of the photoconductor 1 substantially vertically, or the contact direction of the tip of the blade 61 may be the same as the moving direction of the surface of the photoconductor 1. It can be applied to the case where they are arranged in substantially the same direction, and similar effects can be obtained.

In each of the above embodiments, the cleaning blade 61 is used as the cleaning member of the cleaning device 6.
However, the present invention can also be applied to an image forming apparatus such as a copying machine using a fur brush, a magnetic brush or the like as a cleaning member, and similar effects can be obtained.

[0090]

According to the invention of claim 1, since the friction coefficient lowering agent is applied to the surface of the image bearing member by the coating means, the friction coefficient on the image bearing member can be lowered. In particular, when a cleaning blade is used as the cleaning member, it is possible to prevent the blade from curling or chattering. Furthermore, since the development is carried out in a non-contact manner, even though the surface of the image bearing member is slippery due to the friction coefficient lowering agent, unlike the case of the contact development, it is possible to suppress the development unevenness. It becomes possible to prevent the occurrence of image deterioration such as blurring and white spots. Therefore, even when a small-diameter, spherical developer is used, good cleaning performance can be obtained, and high image quality can be obtained due to good development characteristics.

In particular, according to the invention of claim 2 or 3, since the charging member or the transfer member which comes into contact with the surface of the image carrier is used as the member for applying the friction coefficient lowering agent of the applying means, It is not necessary to separately provide a device as a coating means. Therefore, there is an effect that the space can be saved and the device can be downsized.

Particularly, according to the invention of claim 4 or 5, the image carrier is rotated by one or more rotations at a timing when the transfer operation by the transfer device is not performed by the control means, and the transfer member is moved. By controlling the application means so as to apply the friction coefficient lowering agent to the surface of the image carrier, the friction coefficient lowering agent can be reliably applied to the surface of the image carrier without affecting the image forming operation. Can be applied to. Therefore, there is an effect that a better cleaning performance and a better image quality can be obtained.

In particular, according to the invention of claim 6, the linear velocity ratio of the surface of the transfer member to the surface of the image carrier at the time of applying the friction coefficient lowering agent is set to 1.5 to 3. Therefore, it becomes possible to reliably apply a predetermined amount of the friction coefficient lowering agent to the surface of the image carrier. Further, there is an effect that good cleaning performance can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a copying machine according to a first embodiment.

FIG. 2 is a schematic configuration diagram of a developing device of the copying machine.

FIG. 3A is a plan view of a part of the surface of the developing roller of the developing device. (B) is sectional drawing of the surface part of the same developing roller.
FIG. 6C is an explanatory diagram showing a state in which toner is attached to the surface of the developing roller.

FIG. 4 is a schematic configuration diagram of a copying machine according to other embodiments 2 and 3.

FIG. 5 is a schematic configuration diagram of a copying machine according to a fourth embodiment.

FIG. 6 is a schematic configuration diagram of a copying machine according to a fifth embodiment.

FIG. 7 is a schematic configuration diagram of a copying machine according to a sixth embodiment.

FIG. 8 is a schematic configuration diagram of a copying machine according to a seventh embodiment.

FIG. 9 is a schematic configuration diagram of a copying machine according to still another embodiment 8.

FIG. 10 is a schematic configuration diagram of a copying machine according to a ninth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging device 3 Developing device 4 Transfer device 6 Cleaning device 7 Toner 8 Transfer paper 9 Block-shaped zinc stearate 9a Fine zinc stearate powder 21 Charging roller 23 Pressing member 25 Container 41 Transfer roller 43 Spring-like pressing Member 45 Transfer belt 46 Coating roller 61 Cleaning blade 62 Fur brush 402 Intermediate transfer belt 405 Fur brush 406 Spring-like pressing member

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Reference number within the agency FI Technical display location G03G 15/02 101 15/08 507 L 15/16 (72) Inventor Mayumi Yoshida Nakata, Ota-ku, Tokyo Magome 1-36 in Ricoh Co., Ltd. (72) Inventor Hiroshi Yoshinaga 1-3-6 Nakamagome, Ota-ku, Tokyo In-house Ricoh Co., Ltd. (72) Kimitoshi Yamaguchi 1-3-3 Nakamagome, Ota-ku, Tokyo No. 6 In Ricoh Company (72) Inventor Tsukasa Adachi 1-3-3 Nakamagome, Ota-ku, Tokyo In Ricoh Company, Ltd.

Claims (6)

[Claims] 1. A charging device for uniformly charging an image carrier, an exposure device for forming a latent image by irradiating a light image on the image carrier, and a developing device for visualizing the latent image. An image forming apparatus comprising: a transfer device that transfers the visible image on the image carrier to a transfer material; and a cleaning device that cleans the surface of the image carrier after the transfer with a cleaning member. A coating means for coating the surface of the image bearing member with a friction coefficient lowering agent that lowers the frictional coefficient of the surface is provided, and the developing device is configured to visualize the latent image without contacting the image bearing member. An image forming apparatus having the above structure. 2. The image forming apparatus according to claim 1, further comprising a charging device having a charging member in contact with the surface of the image carrier, wherein the charging member is used as a coating member in the coating means. Image forming apparatus. 3. The image forming apparatus according to claim 1, further comprising a transfer device having a transfer member in contact with the surface of the image carrier, wherein the transfer member is used as a coating member in the coating means. Image forming apparatus. 4. The image bearing member is rotated once or more at a timing when the transfer operation by the transfer device is not performed, and the friction coefficient lowering agent is applied to the surface of the image bearing member using the transfer member. 4. The image forming apparatus according to claim 3, further comprising control means for controlling the coating means. 5. When continuously forming images on a plurality of transfer materials, the image carrier is rotated once or more at a timing when the transfer material is not supplied to the transfer device, and the image carrier is carried by the transfer member. 5. The image forming apparatus according to claim 4, further comprising control means for controlling the application means so as to apply the friction coefficient lowering agent to the surface of the body. 6. The linear velocity ratio of the surface of the transfer member to the surface of the image carrier when the friction coefficient lowering agent is applied is 1.
The image forming apparatus according to claim 3, wherein the image forming apparatus is set to 5 to 3.