JPH0339980A - developing device - Google Patents

Abstract

PURPOSE:To permit toner to be adhered on a toner carrying member so as to be carried by large quantity by removing the toner on the toner carrying member after development by means of a triboelectrostatic charging member and triboelectrostatically charging an insulating layer which is provided on the circumferential plane of the toner carrying member to the opposite polarity of the electrostatically charged polarity of the toner. CONSTITUTION:For the toner carrying member 1, on the circumferential surface of a cylinder-shaped conductive base 10, the thin insulating layer 11 is formed by coating, the toner T after the development is scraped away and removed from the circumferential surface by the contact of the triboelectrostatically charging member 8 with the circumferential surface and the insulating layer 11 is electrostatically charged to the opposite polarity of the toner polarity. Then, the toner carrying member 1 comes into contact with the toner being carried on the circumferential plane of a toner supplying member 3 and the toner T is adhered on the toner carrying member 1 and is carried. Thus, the large quantity of the toner T is supplied to the toner carrying member 1 under stable condition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device using a -component developer, and more particularly, to a developing device suitable for a development method using a non-magnetic one-component developer. It is related to the device.

[Problems to be solved by conventional technology and inventions] Recently,
In image forming devices such as electrophotographic copying machines and electrostatic recording devices,
Non-magnetic one-component developers that do not contain carriers have come to be used to make them more compatible with color development and the like.

FIG. 6 shows a conventional example of a developing device suitable for a developing method using such a non-magnetic component developer.

In the figure, a non-magnetic component developer (non-magnetic toner) (not shown) in a developer container 104, which is agitated by an agitator 102, is placed on a roller-shaped toner carrying member 101 rotating counterclockwise. The toner is triboelectrically charged to a predetermined polarity by a roller-shaped toner supply member 103 that rotates in the direction of the toner.

The toner thus supplied and carried is regulated in layer thickness by the dogta blade 105 to form a single layer with a uniform thickness, and its treelectricity is further improved, and the toner is transferred to the developing section 1.
06, where the electrostatic latent image formed on the photoreceptor bell l-107 is visualized.

In this conventional example, the toner carrying member 101 is made of If!, such as chloroprene, on the peripheral surface of a conductive substrate 101a made of aluminum or the like, as illustrated in FIG. Insulation J made of a material
'11O1b, and on top of that, a large number of electrode particles (carbon) 1.01C1 are electrically connected to each other! It is constructed by stacking electrodes N101c which are dispersed in front of the edge.

The dogta blade 105 that thins the toner has an insulating film 105a made of a rubber-like fluorine material such as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) deposited on a substrate. ing. Further, the toner supply member 103 is made of a sponge material such as polyurethane foam, which has a triboelectrification series separated from the toner. Such a developing device.

For example, it is shown in Japanese Patent Application Laid-Open No. 61-4.2672''8-.

By the way, in a developing device that uses magnetic toner for boat fishing,
When carrying toner on a toner carrying member, the magnetic force of an internal magnet is used. However, in a developing device that uses the above-mentioned one-component non-magnetic toner and is easily compatible with color development, such magnetic force is used to carry toner. [Hener supply member 103 and toner support member 101]
and 1-S- to charge the toner by friction,
This is electrostatically adhered and carried on the toner carrying member 101, and the toner-attached member 101.1
03 and the toner, the toner cannot be sufficiently charged, and it is inevitable! Toner carrying member 1
The amount of toner adhering to 01 tends to be insufficient.

In addition to the above-mentioned known techniques, techniques related to toner supply members have been proposed, such as in Japanese Patent Laid-Open No. 60-229057, which uses a conductive foam with a resistance of 10@2 to 10@Ω. Furthermore, the technique disclosed in Japanese Patent Application Laid-open No. 60-229060 uses an elastic roller as a toner supply member, but the technique disclosed in Japanese Patent Application Laid-open No. 6↓-52663,
Techniques using a fur brush as a toner supply member have been disclosed.

In either method, a toner supply member made of a sponge roller, an elastic roller, a fur brush, etc. is rotated in contact with a toner carrying member so as to create a relative speed difference, and the toner is charged by these members. At the same time, the toner is supplied to the toner carrying member, the toner is electrostatically adhered to the toner carrying member by friction with the toner carrying member, and the toner is transported, and the layer thickness of the toner is controlled by a layer thickness regulating member such as a doctor blade. Development is carried out by thinning the layer while controlling it. In addition to using an insulating layer on the surface of the toner carrying member as illustrated in FIG. 7, it has also been proposed to use a medium resistance layer on the surface of the toner carrying member.

According to the developing devices shown in these examples, the adhesion of toner to the carrying member in items 1 to 1 is performed by mutual friction between the toner supply member and the toner carrying member, and the toner is not allowed to adhere to the toner carrying member. However, since the toner is charged by friction, the toner tends to be insufficiently charged as described above, resulting in a small amount of toner adhering to the toner carrying member.

If the amount of toner adhesion becomes small in this way, it becomes impossible to achieve a predetermined image density. In particular, when comparing black toner and color toner, in order to obtain a predetermined image density (in the case of a solid image), the toner adhesion amount for black is 0.4~
0.5+IIg/-, 1.5~ for color
This requires 2.0 times as much toner adhesion, and it has been difficult to employ the conventional structure, especially in a developing device using color toner.

Therefore, as shown in Japanese Unexamined Patent Publication No. 54-51841, after scraping off the toner on the toner carrying member after passing through the developing section, corona discharge is applied to the insulating layer of the toner carrying member. A technique has been proposed in which a charge is applied to the toner by a toner supply member, and then the toner is electrostatically and actively deposited on the toner carrying member by a toner supply member. Since the structure is installed inside the corona discharger, it is necessary to take various measures to prevent toner from entering the corona discharger, especially its charge wire. However, even if various sealing means are used, since the charge wire itself has a dust collection function, toner tends to adhere to the internal charge wire, causing uneven charging.

In view of the above-mentioned points, an object of the present invention is to make it possible to sufficiently and uniformly fffi toner and to make it possible to adhere and carry a large amount of toner on a toner carrying member, thereby obtaining a high-quality image. An object of the present invention is to provide a developing device.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention includes a toner carrying member that carries toner on its peripheral surface and visualizes an electrostatic latent image formed on a latent image carrier with the carried toner in a developing section. A developing device including a toner supplying member that supplies toner to the toner carrying member.

The toner carrying member is a toner carrying member provided with an insulating layer on its circumferential surface that is charged to a polarity opposite to the charging polarity of the toner, and the toner carrying member is provided on the downstream side in the rotational direction of the toner carrying member with respect to the developing section, and is configured to supply toner. A frictional charging member that removes the toner on the toner carrying member after development and triboelectrically charges the absolute a layer to a polarity opposite to the charging polarity of the toner, with respect to a peripheral surface portion of the toner carrying member on the upstream side of the member. We propose a configuration in which the two are in contact with each other.

Furthermore, in order to achieve the same object, the present invention includes a toner carrying member that carries toner on its peripheral surface and visualizes an electrostatic latent image formed on a latent image carrier with the carried toner in a developing section. , a developing device having a toner supplying member that supplies toner to the toner carrying member, wherein the toner carrying member is provided with an insulating layer on one circumferential surface that is charged to a polarity opposite to that of the toner; We propose a structure in which microscopic irregularities are formed on the surface of the insulating layer.

〔Example〕

Embodiments of the present invention will be described below with reference to one drawing.

In the drawing, a roller-shaped toner carrying member 1 is provided with a thin insulator [11,
In other words, it is made of a material covered with a dielectric layer.

The toner carrying member 1 constructed in this manner is driven to rotate in the direction of the arrow in the figure at a linear velocity that is 1 to 4 times the linear velocity of the belt-shaped photoreceptor 7, which is an example of the configuration of a latent image carrier. The agitator 2 agitates the toner carrying member 1 which is actively rotated. Non-magnetic toner (-component developer) (not shown) in the developer container 4 is supplied and carried by the toner supply member 3 . That is, due to the friction between the toner and the toner supply member 3, the toner charged to a predetermined polarity, in this example, to a positive polarity, adheres to the surface of the toner carrying member 1 due to its electrostatic force. The layer thickness of the supported toner is regulated by the layer thickness regulating blade 5 and thinned to a uniform thickness, and then the developing section 6
Here, the electrostatic latent image formed on the photoreceptor 7 is visualized.

The toner carrying member 1 and the photoreceptor 7! - Conductive substrates 10 of the toner carrying member 1 facing each other in contact or non-contact with each other via the lunar.
By applying a predetermined bias voltage of alternating current, direct current, or a combination of alternating current and direct current to the electrostatic latent image, an amount of toner corresponding to the amount of charge of the electrostatic latent image can be attached to the latent image.

Note that the layer thickness regulating blade 5 is formed on the surface of the elastic base body that faces the surface of the toner carrying member 1 .

For example, it is advisable to attach an insulating film made of a fluororesin material such as TE-1-rafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), which is the same as the insulating layer of the toner-carrying member. The blade 5 comes into pressure contact with the toner carrying member 1 as shown in the figure, smoothing the toner layer into a uniform thin layer, and improving and stabilizing the charging characteristics of the toner. The entire layer thickness regulating blade 5 may be made of the materials mentioned above. Further, instead of the layer thickness regulating blade 5, a layer thickness regulating member such as a layer thickness regulating roller that rotates while contacting the toner carrying member may be used.

Here, assuming that the toner used in this example is positively charged, examples of the toner material include resins such as polystyrene, BMA, epoxy, and phenol. A polarity control agent or the like is externally or internally added to such a toner as necessary, and the amount of charge of the toner can be appropriately controlled by such a polarity control agent. External addition means mixing toner particles with a polarity control agent, etc., and internal addition means mixing a polarity control agent or the like into each toner particle to integrate them.

A blade-shaped frictional charging member 8 is provided near the peripheral surface of the toner carrying member 1 on the downstream side in the rotational direction of the toner carrying member 1 with respect to the developing section 6 and on the upstream side of the toner supplying member 3.
is arranged so as to be in constant contact with its peripheral surface.

This frictional 1iF electric member 8 scrapes and removes the toner remaining on a portion of the henna carrying member 1 after development, and at the same time removes the insulating layer 11 of the toner carrying member 1.

It is triboelectrically charged to a polarity opposite to that of the toner, that is, a negative polarity in this example.

As mentioned above, the toner carrying member 1 is made of a cylindrical conductive substrate 10 whose circumferential surface is coated with a thin absolute WJ11. The material of the insulating layer 11, which is negatively charged with the polarity opposite to the iF Ml polarity, is as follows:
Acrylic type, which is charged to the opposite polarity to toner in terms of charging series.
A wide variety of materials such as urethane-based, styrene-based, epoxy-based, and Teflon-based materials can be used. At that time, in order to improve the releasability of the toner, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (P
It is convenient to use fluorine-containing polymer materials or materials containing fluorine-containing polymers, such as FA), polytetrafluoroethylene (TFE), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP). In addition, various insulating materials exemplified in JP-A No. 61-42672 may also be used.

As the frictional charging member 8, the insulating layer 1 of the toner carrying member 1 is used.
It is preferable to use a material which has a triboelectrification series far from 1 and has good releasability from the toner. Examples include rubber-like materials such as silicone-based and urethane-based materials.

When such a frictional charging member 8 comes into contact with the circumferential surface of the toner carrying member 1, as schematically shown in FIG. 2, the toner T after development is scraped off and removed from the circumferential surface. The insulator/111 of the toner carrying member 1 is charged to a negative polarity opposite to that of the toner.

The toner carrying member 1 whose insulating layer 11 is negatively charged comes into contact with the toner carried on the circumferential surface of the toner supplying member 3, and at this time, the toner is adhered and carried on the toner carrying member 1. In this case, unlike the conventional example, since the insulating layer 11 of the toner carrying member 1 is charged to the opposite polarity to the toner by the frictional charging member 8, the toner carrying member 1
The amount of toner that adheres to the surface increases. That is, a large amount of toner can be supplied to the toner carrying member 1 in a stable state.

Due to its insulating properties, the insulating layer 11 has high load retention properties,
When this is triboelectrically charged, the charge is difficult to disappear, so that the toner can be reliably attached to the surface of the insulator/ill.

As the toner supplying member 3, since the electrostatic force due to friction with the toner carrying member 1 greatly contributes, it is preferable to use a urethane-based or acrylic-based sponge material impregnated with a fluorine-based resin. It is also possible to change the resistance value by adding carbon. A good range of specific volume resistivity is about 10 3 to 10 10 ΩO.

The toner supply member 3 may also be constructed of a fur brush, an elastic roller, or the like.

When a fur brush is used as the toner supply member 3, the toner can be triboelectrically charged stably, and toner is less likely to stick to the toner supply member.

In the conventional example shown in FIG. 4, the toner is attached to the toner carrying member by mutual friction between the toner supply member 103 and the toner carrying member 101, and the toner is frictionally charged. Inevitably, the amount of toner adhering to the toner carrying member will be small. In particular, in the case of color development, if the amount of adhesion decreases, it becomes impossible to obtain a predetermined image density.This example solves this technical problem.

Further, in this example, the toner on the toner carrying member 1 is scraped off by the frictional charging member 8, and then a large amount of toner is deposited on the member 1, and this toner is connected to the toner supplying member 3 and the layer thickness is controlled. In order to sufficiently and uniformly charge the toner with the blade 5, even if there is one or more layers of toner, for example, two or more layers as shown in FIG. 2, the sufficiently charged toner in both layers is developed. can be provided to
A high-density, high-quality visible image can be obtained, and background stains can be prevented.

If the remaining toner on the toner carrying member 1 after development is not scraped off and used again for development, this remaining toner will be subjected to the '41F electric action again by the layer thickness regulating blade 5, and the toner will be newly carried on the toner. The amount of IF charge is larger than that of the toner supplied to the member 1, and the amount of charge of the entire toner used for development varies and becomes non-uniform, leading to deterioration of the quality of the visible image. It is possible to prevent such problems and improve the image quality by performing development with uniformly charged toner.

Further, as described above, the frictional charging member 8 scrapes off the toner on the insulating layer 11 on the toner carrying member after development, collects it toward the developer container 4, and charges it to a predetermined amount. At the same time, the charge remaining on #4AmN11 of the toner carrying member 1 after development, that is, the charge on the toner carrying member that has become an afterimage due to contact with the photoreceptor 7, etc., is removed from the toner carrying member 1. Frictional contact with the toner carrying member 1 brings the amount of charge to saturation, making the amount of charge of the insulating layer 11 of the toner carrying member uniform, and also serves to improve the quality of the visible image.

That is, the frictional charging member 8 constitutes an example of the configuration of an initializing means that initializes the toner carrying member.

In this example, a blade-shaped member is used as the triboelectric charging member to achieve such an initialization function.
As indicated by reference numeral 80 in the figure, it may be a roller-shaped roller made of sponge material, for example, in the example of FIG.
At the portion where the roller-shaped frictional charging member 80 contacts the toner carrying member 1.

The toner carrying member is rotated in the opposite direction to the member 1, that is, in one counter direction, and the toner remaining on the surface of the toner carrying member after development is peeled off and cleaned.
By MWA with the toner carrying member 1, the insulating layer 11 is charged to a polarity opposite to that of the toner. With such a configuration, the contact force of the friction '4rF electric member 80 on the toner carrying member can be made uniform, uneven contact with the toner carrying member 1 can be eliminated, and the insulating layer 11 can be charged uniformly. be able to. The roller-shaped friction charging member 80 is also preferably separated from the insulating layer 11 of the toner carrying member 1 on the friction band surface and made of a material that has good releasability from the toner, such as silicone or the like. Urethane foams can be advantageously used. Also absolutely 11111
In order to increase the friction with the surface, it is possible to advantageously use a material impregnated with a fluororesin or a material with a resistance as low as 1012 to 103 Ω. Further, if a blade-shaped member shown in FIG. 1 is used as the frictional charging member.

The tip of this blade is easily damaged, and there is a risk that toner may adhere there and the charging function of the insulating layer 11 may deteriorate early. IIA for a long time
High chargeability against RJ[1 can be maintained.

The configuration, materials, etc. of each member are summarized as follows. Among these materials, practical materials are listed in consideration of releasability from toner and the like.

As mentioned above, the charge polarity of the toner can be controlled to a certain extent by the polarity control agent added to the toner.

Next, in the embodiment shown in FIG. 4, random minute irregularities are formed on the surface of the insulating layer 11 of the toner carrying member 1. The roughness of the unevenness, that is, the depth thereof, is set to 10 to 100μ, preferably 20 to 50μ. The other configurations are completely the same as those shown in FIGS. 1 to 3, and the blade-shaped friction charging member shown in FIG. 1 and the roller-shaped member shown in FIG. 3 are used as appropriate. (a roller-shaped triboelectric charging member 80 is shown in FIG. 4).

According to the above configuration, the toner T supplied to the surface of the toner carrying member by the toner supplying member 3 is carried not only by electrostatic force but also by mechanical action due to the unevenness of the surface of the toner carrying member. An amount of toner corresponding to the layer adheres to the toner carrying member 1. FIG. 4 schematically shows the state of the toner particles at this time, similar to FIG. 2. In this way, the effect of the unevenness is A large amount of toner is carried on the toner carrying member 1, its layer thickness is regulated by the layer thickness regulating blade 5, and the toner is further triboelectrically charged. ,
Even after regulating the layer thickness, it is possible to form toner layers in an amount equivalent to two or more layers on the toner carrying member 1. Moreover, it is possible to stabilize the charging of the toner, that is, increase the amount of charging per unit volume of the toner, and achieve uniform charging over the entire toner. Therefore, a high-quality visible image with high toner concentration can be formed on the photoreceptor 7 developed in the developing section 6, and even when color toner is used, the image quality can be significantly improved.

As described above, it is possible to stably supply a large amount of toner onto the toner carrying member 1 and to stabilize the charging thereof. , $1 of the toner carrying member l by the triboelectric charging member 8.80 (Figs. 1, 3, and 4).
! charging the a layer 11 to a polarity opposite to that of the toner and electrostatically adhering the toner to the toner carrying member 1;
This is a synergistic effect of forming unevenness on the surface of the toner carrying member 1 and mechanically adhering the toner to the surface, but the toner can be effectively carried only by the unevenness without providing the frictional charging members 8 and 80. Even if it is configured to be supported on a member, the above-mentioned effects can be obtained.

In the example shown in FIG. 4, the surface of the conductive substrate 10 made of a roller with a smooth surface is roughened by sandblasting or the like to form minute irregularities, and the surface is coated with an insulating material 11.
is coated by spraying, for example, and dried to form irregularities on the surface of the insulating layer 11,
If the unevenness is formed by such a method, a predetermined toner carrying member 1 can be easily manufactured.

Further, as shown in FIG. 5, after a compaction layer 11 is laminated on the surface of a conductive substrate 10 made of a roller with a smooth surface, the surface of this insulating layer 11 is roughened by sandblasting, filing, etc. It is also possible to form unevenness.

As described above, in the developing section 6, the photoreceptor 7 and the toner carrying member 1 are separated from each other, and an alternating current, direct current, or direct current plus alternating current voltage is applied to the conductive substrate 10 of the toner carrying member 1. Although non-contact development can be performed by electrostatically flying the toner on the photoreceptor 7 onto the electrostatic latent image, it is possible to perform non-contact development by electrostatically flying the toner on the electrostatic latent image on the photoreceptor 7. In addition, since the I-ner conveyed to the developing section 6 can be multilayered and charged in a stable state,
The toner is easily caused to fly onto the electrostatic latent image in the developing section 6, and reliable non-contact development can be performed.

Conversely, if the photoconductor 7 and the toner carrying member 1 are configured to contact each other via the toner to perform contact development, the gap between the toner carrying member 1 and the photoconductor 7 can be managed as in a non-contact development system. However, when performing such contact development, if the toner carrying member 1 and the photoreceptor 7 are made of rigid bodies, there is a risk that one or both of them may be damaged. As shown in Figure 1,
It is advantageous to use a flexible bell 1 as the photoreceptor and to bring it into contact with the toner carrying member 1 with uniform pressure.

The present invention can be widely applied to developing devices in various image forming apparatuses other than those using electrophotography. Further, the present invention is also applicable to a developing device using a one-component magnetic toner developer.

〔Effect of the invention〕

According to the configuration of the present invention, toner easily adheres to the toner carrying member, and a large amount of toner can be triboelectrically charged stably and uniformly, so that an image with good density can be obtained. 1 image quality is further improved, and background stains are less likely to occur.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of the peripheral portion of the toner carrying member to explain that the toner carrying member is triboelectrically charged by a frictional charging member.
FIG. 3 is a schematic sectional view of a main part of another embodiment, and FIG. 4 is a diagram showing an example of a developing device in which unevenness is formed on the surface of a toner carrying member.
FIG. 5 is a cross-sectional view of a toner carrying member in which unevenness is formed using a method different from that shown in FIG. 4, FIG. 6 is a schematic cross-sectional view of a conventional example, and FIG.
The figure is a partially enlarged sectional view of a conventional toner carrying member. 1... Toner carrying member 3... Toner supplying member 6... Developing section 7... Photoreceptor as a latent image carrier 8. 80... Frictional charging member

Claims (2)

[Claims] (1) A toner carrying member that carries toner on its peripheral surface and visualizes the electrostatic latent image formed on the latent image carrier with the carried toner in a developing section, and supplies toner to the toner carrying member. In the developing device having a toner supplying member, the toner carrying member is a toner carrying member provided with an insulating layer on its circumferential surface that is charged to a polarity opposite to that of the toner, and the toner carrying member is rotated in a rotational direction relative to the developing section. The toner on the toner carrying member after development is removed from the peripheral surface of the toner carrying member on the downstream side and upstream of the toner supplying member, and the insulating layer is charged with a polarity opposite to that of the toner. A developing device comprising a frictional charging member that is brought into contact with a frictionally charging member. (2) A toner carrying member that carries toner on its peripheral surface and visualizes the electrostatic latent image formed on the latent image carrier with the carried toner in a developing section, and supplies the toner to the toner carrying member. In the developing device, the toner carrying member is a toner carrying member having an insulating layer on its circumferential surface that is charged to a polarity opposite to that of the toner, and a surface of the insulating layer is provided with minute irregularities. A developing device characterized in that: