JPH0611958A - Developing device - Google Patents

Abstract

PURPOSE:To stably operate a developing device without toner leakage for a long time by positioning the extreme ends of both ends pinchedly holding part of an clastic regulating member on the upper stream side in the rotational direction of a developer bearing member. CONSTITUTION:A developing vessel 5 which is the stuck part of a seal member 4 is formed with a recessed part of a proper size on the position opposite to a blade end part 3b, and the seal member 4 is brought in contact with a developing roller 2 and the blade end part 3b by appropriate pressing force. It is prevented that the seal member 4 comes in contact with both end parts 3b of the elastic blade 3 by excessive pressure so as to deform the blade part 3a. In this case, the passage through which toner accumulated on the edge part of the elastic blade 3 flows to both end parts, in lengthwise direction, of the elastic blade 3 can be intercepted by the cutout part 3c formed on the elastic blade 3. Hereby, spill of toner to an image forming device or a copy paper taking place by invasion of toner to both end edge parts of the elastic blade 3 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a copying apparatus, a printer,
The present invention relates to a developing device that visualizes a latent image formed on the surface of an image bearing member such as an electrophotographic photosensitive member or an electrostatic recording dielectric in an image forming apparatus such as a facsimile, and particularly develops using toner particles. The present invention can be effectively applied to a dry developing type developing device that performs

[0002]

2. Description of the Related Art Conventionally, various types of dry one-component developing devices have been proposed and put into practical use. However, it is extremely difficult to form a thin layer of the dry one-component developer by any of the developing methods. However, at the present time when improvements in the resolution and sharpness of developed images are required, it is essential to develop a method and apparatus for forming a thin layer of a dry type one-component developer that can meet this demand, and in response to this, Several measures have been proposed.

For example, as disclosed in Japanese Unexamined Patent Publication No. 54-43038, a rubber or metal elastic regulating member, that is, an elastic blade, is brought into pressure contact with a developing roller which is a developer carrying member, and toner is applied to this contact nip portion. To form a thin toner layer on the developing roller and to give sufficient tribo to the toner by friction there.

Further, when the application of the non-magnetic toner is regulated with the above configuration, a separate toner supply member is required. The magnetic toner can supply the toner onto the developing roller by the magnetic force of the magnet in the developing roller, but the non-magnetic toner requires a mechanical supplying means. Therefore, the applicant of the present invention, in Japanese Patent Application Laid-Open No. 58-116559, arranges the toner supply roller 6 in contact with the developing roller 2 on the upstream side of the elastic blade 3 in the rotating direction of the developing roller, as shown in FIG. However, there is proposed a developing device for stripping the undeveloped toner on the developing roller 2 and supplying the toner to the developing roller 2.

As described above, by using the elastic blade 3, it is possible to favorably form a uniform thin layer of the one-component developer on the developing roller 2. However, with this configuration, toner easily leaks from the end portion of the elastic blade 3 in the longitudinal direction, and it is important to prevent this. If the sealing property of this end portion becomes insufficient, the toner layer corresponding to this portion in the longitudinal direction of the developing roller 2 will be formed thicker than other portions regulated by the elastic blade 3, and as a result, There arises a problem that these excessive developers spill out of the developing device and stain various components in the image forming device and the transfer paper. In particular, this phenomenon becomes remarkable when a non-magnetic toner that cannot use the action of the magnetic field is used to hold the toner on the developing roller 2.

In order to prevent this problem, conventionally, as shown in FIGS. 7 and 8, the seal member 4 is brought into contact with the edge surfaces of both ends of the elastic blade 3, that is, the hatched area in FIG. It is arranged to be placed.

That is, in FIG. 8, the elastic blade 3 is pressed against the developing roller 2 from above, except for both ends in the longitudinal direction of the developing roller 2. The seal member 4 is
The seal is provided in the opening of the developing container 5, and seals the gap formed between the outside of both ends of the press contact portion of the elastic blade 3 with the developing roller 2 and the container 5, and as shown in FIG. By preventing the toner from leaking from both ends of the elastic blade 3 in the longitudinal direction, the side surface of the member 4 and the both edges of the elastic blade 3 in the longitudinal direction, that is, the regions shown by hatching in FIG. is doing.

In such a conventional example, it is not possible to suppress the dimensional tolerance of the components themselves such as the elastic blade 3, the seal member 4, the developing container 5 and the variation in the mounting position of the elastic blade 3 and the sticking position of the seal member 4. However, it is extremely difficult during mass production of the apparatus, and a gap may occur between the end of the elastic blade 3 in the longitudinal direction and the seal member 4, and the toner 7 may leak out immediately after the start of the developing operation.

Therefore, as a more reliable sealing method, as shown in FIG. 9, the longitudinal ends of the elastic blade 3 are sandwiched between the developing roller 2 and the sealing member 4 to improve the sealing performance. It has been proposed to shorten the free length of both ends of the elastic blade 3 in the longitudinal direction.

[0010]

However, even in the structure in which both longitudinal ends of the elastic blade 3 are sandwiched between the developing roller 2 and the seal member 4, the sealing property is insufficient and the developing operation is repeated many times. However, toner leakage occurs from both ends in the blade longitudinal direction, and the problem of contamination of the inside of the machine and the transfer paper cannot be completely solved. The cause is considered to be as follows.

That is, since the elastic blade 3 has a function of regulating the thickness of the toner layer thickly coated on the developing roller 2 by the rotation of the toner supply roller 6, the elastic blade 3 rotates with the rotation of the developing roller 2. The toner sent to the contact portion of the elastic blade 3 collects at the edge portion of the elastic blade 3. Then, as the developing operation is repeated many times, the toner accumulated on the edge portion of the elastic blade 3 is
It is sent along the edge portion to the end portion of the developing container 5. That is, it is the direction of arrow B in FIG. for that reason,
As a result, the toner invades into a slight gap between the seal member 4 and both end portions of the elastic blade edge portion, and the toner leaks out from both end portions of the elastic blade.

Therefore, an object of the present invention is to prevent the toner accumulated at the edge (tip) of the elastic regulating member from being transmitted to the edge portion of the elastic regulating member and being sent to both ends in the longitudinal direction of the elastic regulating member. However, it is another object of the present invention to provide a developing device capable of preventing the inside of the apparatus and the transfer paper from being contaminated due to toner leakage from both ends of the elastic regulation member.

[0013]

The above object can be achieved by the developing device according to the present invention. In summary, the present invention has a developing container that has an opening at a portion facing the image bearing member, and stores a one-component developer, and the image bearing member that bears a latent image face each other at the opening. To form a developing section for supplying a one-component developer, and a developer carrying member carrying and carrying the developer from the developing container to the developing section; and a surface of the developer carrying member which is pressed against the surface of the developer carrying member. An elastic regulating member for regulating the amount of developer to be applied, wherein the length of the elastic regulating member in the longitudinal direction is longer than the developer supply opening of the developing container but shorter than the developer carrying member. Further, in a developing device having a seal member between the developer carrying member and the developing container, both ends in the longitudinal direction of the elastic regulating member are sandwiched between the seal member and the developer carrying member, Both ends in the longitudinal direction of the elastic restriction member Of the pinch portion located upstream in the rotation direction of the developer carrying member is at least upstream of the tip end of the elastic regulating member adjacent to the tip end of the pinching part in the developer carrying member rotation direction. Is a developing device. Preferably, the free length of the tip portion of the elastic restriction member is formed to be short only in the portion adjacent to the tip portion of the sandwiching portion. Further, the developing device is provided with an elastic roller rotatably supported while being in contact with a position on the upstream side of the elasticity regulating member in the rotation direction of the developer carrying member, and the developer is composed only of non-magnetic toner. A one-component developer is used.

According to a second aspect of the present invention, a developing container having an opening at a portion facing the image carrier and containing a one-component developer; the image carrier carrying a latent image; A developer holding member that forms a developing unit that supplies the one-component developer facing each other at the opening, and a developer holding member that carries and conveys the developer from the developing container to the developing unit, and an elastic member for the developer holding member And a rotatable developer supply / separation member for supplying the developer to the developer-carrying member and separating the developer, and a downstream side of the developer-supplying / separating member in the rotation direction of the developer-carrying member. A developing device having a developer regulating member that abuts against the developer carrying member to regulate the layer thickness of the developer on the developer carrying member, and imparts an electric charge to the developer. The rotation center axis of the developer supply / separation member is set to the developer Coordinates positioned below the rotation center axis of the holding member and having a contact portion of the developer regulating member with respect to the developer carrying member with a vertical line and a horizontal line passing through the rotary shaft of the developer carrying member as axes. A straight line which is located in the first quadrant of the space and which passes through the most downstream point in the rotation direction of the developer carrying member and the rotation center of the developer carrying member of the contact portion of the developer supply / peeling member with respect to the developer carrying member. And an angle θ formed by the straight line passing through the rotation center of the developer carrying member and the most upstream point of the developer carrying member contacting portion in the rotation direction of the developer carrying member is 50 ° ≦ θ ≦ 80 °. Further, there is provided a developing device characterized in that the developer regulating member and the developer supplying / peeling member are arranged with respect to the developer carrying member. Preferably, the rotation direction of the developer supply / peel member is opposite to that of the contact portion with the developer carrying member. Also, preferably, the outer peripheral diameter of the developer supply stripping member (R _1), the relationship between the outside diameter of the developer carrying member (R ₂₎ includes a 0.7R ₂ ≦ R ₁ ≦ R ₂ . Further, the developer supplying / peeling member is formed of an elastic body having a foam skeleton structure or a fur brush. Furthermore, the developer regulating member is an elastic regulating blade that is elastically biased to the developer carrying member, and its contact state is counter abutting with respect to the rotation direction of the developer carrying member. To be done.

According to the third aspect of the present invention, a developing container having an opening at a portion facing the image carrier and containing a developer, the image carrier carrying a latent image, and the opening. And a developing section for supplying the developing agent to the developing section, and a developing agent carrying member for carrying and carrying the developing agent from the developing container to the developing section, and a developing method for supplying the developing agent to the developing agent carrying member. In a developing device having an agent supply means,
The developer supplying means is formed of a single foam foam rubber, and the foam rubber has a rubber hardness of 8 ° to 15 °.
A developing device characterized by being (Asker C) is provided. Preferably, the supply unit supplies the developer by contacting the developer carrying member and rotating. Further, the developing container includes a toner storage container and a developing device including the developer carrying member, and the supply unit is provided in a toner supply section of the toner storage container and is rotated to The toner in the toner container is supplied into the developing device.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The developing device according to the present invention will be described in more detail below with reference to the drawings.

(First Embodiment of the Present Invention) Embodiment 1 FIG. 1 shows a developing device according to a first embodiment of the present invention.
In this embodiment, the developing device develops an electrostatic latent image formed on an image carrier that rotates in the direction of arrow a in the drawing, for example, an electrophotographic photosensitive member 1 to form a visible image (toner image). Is.

The developing device has a developing roller 2 as a developer carrying member in a developing container 5 having an opening facing the photoconductor 1. The developing roller 2 is rotatably carried by a bearing (not shown) and is rotationally driven in the direction of arrow b.
Further, the developing roller 2 is located at the opening of the developing container 5, and in FIG. 1, the substantially right half peripheral surface thereof projects into the developing container 5,
A generally left half peripheral surface is exposed outside the developing container 5. The exposed surface of the developing roller 2 outside the container is facing or in contact with the photoconductor 1 with a small gap. The developing roller 2 can be made of, for example, a sleeve-shaped metal material such as aluminum, and in some cases, a conductive rubber roller may be used.

In this embodiment, as shown in FIG. 2, the elastic blade 3 as the elastic regulating member is attached to the blade supporting sheet metal 8, and the notches 3c are formed in the vicinity of both ends of the elastic blade 3. It Also, of the elastic blade 3,
Both ends 3b on the further outside of the notch 3c are sandwiched between the seal member 4 and the developing roller 2.

The blade portion 3a of the elastic blade 3 located in the center of the cutout portion 3c is in pressure contact with the outer surface of the developing roller 2 by surface contact.

Further, as will be described in detail later, an elastic roller 6 which is a developer supply / separation member for the developing roller 2 is rotatably supported and is in contact with the outer surface of the developing roller 2. In this elastic roller 6, the contact point between the elastic roller 6 and the developing roller 2 is larger than that of the blade portion 3a.
It is arranged so as to be located on the upstream side in the rotation direction of.

Next, the operation of the developing device of this embodiment constructed as described above will be described.

The elastic roller 6 rotates in the direction of arrow c in FIG. 1, and the toner 7 is carried to the vicinity of the developing roller 2 by this rotation, and on the elastic roller 6 at the contact portion between the developing roller 2 and the elastic roller 6. The toner 7 carried on the developing roller 2 is frictionally charged by being rubbed against the developing roller 2 and adheres to the developing roller 2.

After that, as the developing roller 2 rotates, the toner 7 attached to the developing roller 2 enters the contact portion between the elastic blade 3 and the developing roller 2, and when passing there, the surface of the developing roller 2 and the blade portion. It is rubbed by both 3a and is sufficiently frictionally charged.

The toner 7 thus charged escapes from the contact portion between the elastic blade 3 and the developing roller 2, whereby a thin toner layer is formed on the developing roller 2. This thin toner layer is conveyed to the developing unit facing the photoconductor 1.

The developing roller 2 and the photoconductor 1 have a minute gap in the developing section, and an AC voltage having a DC superimposed thereon is applied between them. As a result, the toner 7 formed in a thin layer on the developing roller 2 is transferred to the photoconductor 1 corresponding to the electrostatic latent image on the photoconductor 1 to form a toner image as a visible image.

The undeveloped toner that has not been consumed in the developing section is collected from the lower portion of the developing roller 2 as the developing roller 2 rotates. A seal member 9 is provided in the collecting portion to allow passage of undeveloped toner into the developing container 5 and to prevent the toner 7 in the developing container 5 from developing.
Prevent leakage from the bottom of the. The collected undeveloped toner on the developing roller 2 is peeled off from the developing roller 2 at the contact portion between the elastic roller 6 and the developing roller 2. Most of the peeled toner is conveyed as the elastic roller 6 rotates, and is mixed with the toner 7 in the developing container 5, and the charge of the charged toner is dispersed. At the same time, new toner is supplied onto the developing roller 2 by the rotation of the elastic roller 6, and the above-described operation is repeated.

Preferably, the peripheral surface of the developing roller 2 is provided with an appropriate rough surface, and the surface of the developing roller 2 and
The probability of rubbing against the toner 7 is increased, and the transportability of the toner 7 is improved. This rough surface has a surface roughness R _Z of 1 μm.
The amorphous sand blasting treatment is performed with alundum abrasive grains as much as possible, and the fixed sand blasting treatment with glass beads is performed. Further, in order to form the rough surface of the convex portion, conductive particles such as particles of metal oxide, graphite, carbon, etc. which can independently form the convex portion are used, and these particles are bound to form the concave portion. The rough surface may be formed by using a resin such as phenol or fluorine.

In this embodiment, as the developing roller 2, an aluminum sleeve having a diameter of 16 mm is used, and the surface of this sleeve is subjected to a fixed blast treatment with glass beads (# 600), and R _Z is set to about 4 μm. Using.

The elastic roller 6 is made of a metal cored bar with fibers such as nylon and rayon, and is made into a brush roller, a urethane foam is wound, a sponge is covered with a rubber skin. It is desirable to cover with a layer, and in this embodiment, an Everlite (trade name) sponge is wrapped around a stainless steel core having a diameter of 5 mm,
A roller having a diameter of 14 mm was used. Further, the elastic roller 6 is rotated in the same direction as the rotation of the developing roller 2,
That is, the abutting portions of the two should be in opposite directions, and
It is desirable that the relative speed with respect to the developing roller 2 be 50 to 300 mm / sec, and in this embodiment, it was set to 70 mm / sec.

In this embodiment, the toner 7 is a non-magnetic one-component type developer, which is a dispersion of a pigment such as carbon in various thermoplastic resins such as styrene resin, acrylic resin or polyethylene resin. Therefore, in this embodiment, a developer obtained by externally adding 1.5% by weight of colloidal silica to a toner powder having an average particle diameter of 10 μm and composed of a copolymer of styrene / acrylic resin and styrene-butadiene resin and a pigment was used.

Next, the elastic blade 3 will be described in more detail.

As described above, as the elastic blade 3, a plate-shaped rubber material such as silicon or urethane, a metal elastic body such as SUS or phosphor bronze, or a rubber material lined with a metal material is used. In this embodiment, silicon rubber is used, and as shown in FIG. 2, the elastic blade 3 is provided with the notches 3c near both ends thereof.

The silicone rubber blade 3 is
The blade supporting sheet metal 8 was attached using a silicone adhesive or the like, and both ends 3b of the elastic blade 3 were sandwiched between the seal member 4 and the developing roller 2.

The seal member 4 is preferably made of Teflon (trade name) felt or the like, which has a belt-like body and has appropriate elasticity. In addition to this, sponge, urethane foam, etc. can also be applied. In this embodiment, as the elastic blade 3,
Silicon rubber having a thickness of 1 mm was used, and Teflon felt was used as the seal member 4.

Further, in the developing container 5 which is the sticking portion of the seal member 4, a proper amount of concave portion (not shown) is formed at a portion facing the blade end portion 3b, so that the seal member 4 has an appropriate pressure contact force. Then, the developing roller 2 and the blade end portion 3b are brought into contact with each other. With this configuration, it is possible to prevent the seal member 4 from contacting both end portions 3b of the elastic blade 3 with excessive pressure and deforming the blade portion 3a.

With such a configuration, the toner 7 accumulated on the edge portion of the elastic blade 3 travels toward the both ends in the longitudinal direction of the elastic blade 3, that is, the path in the direction of arrow A in FIG. It is possible to prevent the toner from spilling in the image forming apparatus or on the transfer paper, which can be blocked by the notch 3c formed, which is a conventional problem, and which is caused by the toner wrapping around the both edges of the elastic blade 3. It becomes possible.

The shaded portion m in FIG. 2 indicates the contact nip portion between the elastic blade 3 and the developing roller 2. However, in order to obtain a proper toner layer thickness on the developing roller 2, the shaded portion m is elastic. The edge portion of the blade 3 has a contact nip portion m
From the upstream side to the upstream side in the rotation direction of the developing roller 2 by about 0.2 to 2
It extends for about mm. Therefore, a small amount of toner is present in the blade free end on the upstream side in the rotation direction of the developing roller 2 from the contact nip portion m and the wedge-shaped space surrounded by the developing roller 2, and these toners are also at both ends of the elastic blade 3. A phenomenon occurs that is transmitted to the department. Therefore, the elastic blade 3
The edge portion of the elastic blade 3 corresponding to the cutout portion 3c is more preferably located in the contact nip portion m, and a reliable toner leakage prevention effect can be obtained.

In this embodiment, the distance from the contact nip portion m to the elastic blade edge portion is about 2 mm, the contact nip portion width is about 1 mm, and the notch length in the developing roller rotating direction is 1.
Good results could be obtained by setting the notch length in the longitudinal direction of the developing roller to 1 mm.

Since the toner layer is formed on the surface of the developing roller 2 corresponding to the cutout portion 3c in an amount less than an appropriate amount, the cutout portion 3c is preferably provided in the non-image area. The blast region is also preferably located between the notches 3c in the vicinity of both ends of the blade in terms of leakage prevention.

Further, the set pressure of the blade portion 3a with respect to the developing roller 2 is preferably 5 g / cm to 200 g / cm (the linear pressure in the generatrix direction of the developing roller 2), and in this embodiment, the hardness is 60 ° (JISA). 50 g / c of silicone rubber
It was pressed against the developing roller 2 with a linear pressure of m.

The blade set pressure is measured at 20 μm.
Three thick SUS thin plates are used to press the nip portion m of the blade portion 3a.
One of the sheets was pulled out with a spring, and the set pressure per cm was calculated from the friction coefficient of the SUS thin plate.

The incorporation of such constructed developing apparatus Canon Corp. FC-5 copier, frequency 1800H _Z, peak-to-peak voltage 1200 as a bias power source
A latent image potential on the photoconductor 1 is set to a dark portion of −540 V and a light portion of −1 by using a DC voltage of −250 V superimposed on an AC voltage of V.
50V, and the distance between the developing roller 2 and the photoconductor 1 is 250μ
After setting to m and developing about 3000 sheets,
Toner did not leak from both edges of the elastic blade 3 in the longitudinal direction, and a good image without contamination of the toner inside the apparatus and on the transfer paper could be obtained.

Embodiment 2 FIG. 3 shows an elastic blade 3 used in the developing device of the present invention.
Another embodiment will be described.

In this embodiment, the free ends 3b of the elastic blade 3 in the longitudinal direction are formed longer than the blade 3a, and the ends 3b are sandwiched between the seal member 4 and the developing roller 2. .

In the case of such a configuration,
Since the blade portion 3a and the both end portions 3b have a step, and the edge portion of the both end portions 3b of both edge portions is located on the upstream side in the rotation direction of the developing roller 2, the blade portion 3
By blocking the toner path from the edge portion to the edge portion of a, the same effect as that of the first embodiment can be achieved.

If the free length of the both end portions 3b is set to be 1 to 2 mm longer than the blade portion 3a, it is possible to prevent the toner from traveling along the edge portion and reaching the end portion. Since the contact area with the roller 2 becomes large, the driving torque of the developing roller 2 is likely to become excessive, and it is desirable to minimize the driving torque.

Embodiment 3 FIG. 4 shows an elastic blade 3 used in the developing device of the present invention.
Another embodiment will be described.

In this embodiment, both longitudinal end portions 3b of the elastic blade 3 are formed so as to continuously extend outward, and the both end portions 3b are provided between the seal member 4 and the developing roller 2. It gets caught.

Even in such a configuration, the blade portion 3
Since the edge portions of both end portions 3b are located on the upstream side in the rotation direction of the developing roller 2 toward the both end portions with respect to the edge portion of a, the toner is prevented from moving from the edge portion of the blade portion 3a to both end portions 3b. This can be prevented, and the same effect as that of each of the above-described embodiments can be obtained.

Incidentally, in the above-mentioned Examples 1 to 3, the developing device using the non-magnetic one-component toner has been described.
The present invention is also applicable to a developing device that uses the elastic blade 3 for magnetic one-component toner.

Embodiment 4 FIGS. 5A to 5E show various forms of the elastic blade 3 which can be used in the developing device of the present invention. The blade at one end of the elastic blade 3 is shown in FIG. Part 3a, notch 3c
3 is a front view showing the end portion 3b and the end portion 3b, and a hatched portion formed on the end portion 3b indicates a holding portion by the seal member 4. FIG.

These figures show the state before the elastic blade 3 is brought into contact with the developing roller 2. In the first embodiment of the present invention, the free lengths of the blade both-ends sandwiching portion 3b and the free length of the blade portion 3a are formed to be equal to each other.
As shown in (a) and (b), both ends of the blade holding portion 3b
The free length of the shaded area in the figure is the cutout 3c adjacent to it.
Can be made longer or shorter than the blade portion 3a as long as it is formed longer than the free length.

Further, the shape of the cutout portion 3c is not limited to the concave shape shown in the first embodiment, and the shape shown in FIG.
As shown in, it may be cut out in a substantially semicircular shape. This shape has an advantage of being strong against tearing of the cutout portion 3c due to rotation of the developing roller. Further, it can be formed in a triangular shape as shown in FIGS. 5 (d) and 5 (e), and various changes can be made, and the same leak prevention effect can be obtained in any case.

As described above, in the developing device according to the first aspect of the present invention, both ends in the longitudinal direction of the elastic blade are
In the configuration of being sandwiched between the seal member and the developing roller, the tip of the elastic blade at both end clamping portions is at least upstream with respect to the tip of the elastic blade at the inner portion of the blade both edge clamping portions inwardly of the longitudinal container. Since the elastic blade is configured to be positioned at, it is possible to prevent the toner accumulated at the tip of the elastic blade from traveling along the tip and heading to the nip on both ends of the long side, and even if the developing operation is repeated many times, the toner leaks for a long time. It is possible to perform stable operation without

(Second Aspect of the Invention) As described above, the developing device shown in FIG. 6 includes the elastic blade 3, the developing roller, and
That is, the supply roller 6 as a developer supply / separation member is arranged in contact with the developing sleeve 2 on the upstream side of the contact portion of the developing sleeve 2 in the developing sleeve rotation direction, and the toner is supplied to the developing sleeve 2 and the developing sleeve. The undeveloped toner on 2 is stripped. With such a simple configuration, it is possible to faithfully reproduce a solid black image of high density and a large area, and always provide a stable image.

However, in the case where the toner as the developer is quantitatively supplied to the developing sleeve 2 from above or laterally of the developing sleeve 2, the elastic blade 3 and the supplying roller 6 are applied to the developing sleeve 6. Depending on the contact position and contact state, the following image problems occurred.

Now, as shown in FIG. 14, the elastic blade 3
The angle between a straight line passing through the most upstream point D of the contact portion and the rotation center O ₁ of the developing sleeve 2 and a straight line passing through the most downstream point E of the contact portion of the supply roller 6 and the rotation center O ₁ of the developing sleeve 2 is θ. And

The toner supplied by the supply roller 6 to the vicinity of the surface of the developing sleeve is conveyed to the elastic blade abutting portion by the rotation of the developing sleeve 2, where it is regulated to have an appropriate layer thickness and is conveyed to the developing portion. And those returned to the container.

Here, the supply roller 6 is the developing sleeve 2
When rotating in the same direction as, and the angle (θ)
Is small, the toner returned to the inside of the developing container 5 directly drops on the supply roller 6 and is supplied to the contact portion with the developing sleeve 2 again, forming a small circulation.

It is difficult for the toner in such a state to be replaced with new toner 7 in the developing container, and an excessive load is repeatedly applied from the supply roller 6 and the elastic blade 3 so that the toner gradually increases. The physical properties change, and as a result, the density of the image is reduced and toner adheres to the non-image portion (fogging).

This phenomenon occurs when the central axis position of the supply roller 6 is above the central axis position of the developing sleeve 2 or when the contact position of the elastic blade 3 is a vertical line and a horizontal line passing through the developing sleeve shaft. This occurs remarkably when the coordinate space is in the fourth quadrant, or when the outer diameter of the supply roller 6 is larger than the outer diameter of the developing sleeve 2.

Further, as shown in FIG. 15, when the above-mentioned angle (θ) is extremely large, the elastic blade contact portion D
Since the distance between the supply roller abutting portion E and the supply roller abutting portion E is wide, the toner circulation, which should occur due to the rotation of the developing sleeve 2, the regulation of the elastic blade 3, and the rotation of the supply roller 6, is easily delayed.
A blocking phenomenon occurs in which the toner sent from the lateral direction is gradually clogged in the vicinity of the developing sleeve, and also in this case, a phenomenon such as density or fog occurs in terms of image. Then, this phenomenon becomes remarkable when the outer diameter of the supply roller 6 is much smaller than the outer diameter of the developing sleeve 2 or when the fluidity of the toner deteriorates under high temperature and high humidity.

According to the second aspect of the present invention, the positional relationship between the elastic blade 3 contacting the developing sleeve 2 and the supply roller 6 and the ratio of the outer peripheral diameters of the developing sleeve 2 and the supply roller 6 are set within appropriate ranges. By the definition, a developing device is provided which can prevent image density loss due to changes in toner physical properties over time and fogging due to toner blocking.

Next, an example of the developing device according to the second aspect of the present invention will be described.

Embodiment 5 FIG. 10 shows an embodiment of the developing device according to the present invention. In this embodiment, the developing device develops an electrostatic latent image formed on an image carrier that rotates in the direction of arrow a in the drawing, for example, an electrophotographic photosensitive member 1 to form a visible image (toner image). Is.

The developing device has the same structure as that described above with reference to FIG. 1 and the like.
And includes a developing container 5, a developing roller as a developer carrying member, that is, a developing sleeve 2, an elastic blade 3 as an elastic regulating member, and a supplying roller as a developer supplying / peeling member. ing.

The developing container 5 has an opening extending in the longitudinal direction of the developing device, that is, a direction perpendicular to the paper surface of FIG. 14, and the developing sleeve 2 is rotatable in the direction of the arrow b in this opening. It is installed in. The developing sleeve 2 is made of a non-magnetic material such as aluminum and has a surface shape as described later. Further, the developing sleeve 2 is the developing container 5
1, the roughly right half peripheral surface thereof projects into the developing container 5 and the roughly left half peripheral surface thereof is exposed outside the developing container 5 in FIG. The exposed surface of the developing sleeve 2 outside the container is facing or in contact with the photoconductor 1 with a small gap.

Behind the developing sleeve 2, a supply roller 6 is provided.
Are arranged so as to rotate in sliding contact with the projecting surface of the developing sleeve 2 in the developing container. The supply roller 6 is the developing sleeve 2
In the same direction, the developer is supplied to the developing sleeve 2 by rotating in the direction of arrow c in the figure, and the toner on the developing sleeve 2 is peeled off by elastically contacting the developing sleeve 2.

An elastic blade 3 is disposed in contact with the developing sleeve 2 downstream of the sliding contact portion between the supply roller 6 and the developing sleeve 2 in the rotational direction of the developing sleeve 2. In, the passage of the developer on the developing sleeve 2 is regulated.

First, in this embodiment, the supply roller 6
Toner supplied near the developing sleeve 2 by the rotation of the
Is conveyed to the sliding contact portion with the supply roller 6 by the rotation of the developing sleeve 2, and then enters the contact portion between the elastic blade 3 and the developing sleeve 2, and is carried on the surface of the developing sleeve 2.

Further, when the toner 7 passes through the contact portion between the elastic blade 3 and the developing sleeve 2, the toner 7 is slidably contacted by the surface of the developing sleeve 2 and the elastic blade 3 and is further subjected to frictional charging, so that the toner 7 is sufficiently charged. Is frictionally charged.

The toner 6 thus sufficiently triboelectrified is formed as a thin toner layer on the developing sleeve 2 by passing through the contact portion between the elastic blade 3 and the developing sleeve 2, and the developing sleeve 2 The upper part is conveyed to the developing section facing the photosensitive drum 1. In the developing section, a part of the toner is consumed by the developing operation, and the other toner is collected from the lower part of the developing sleeve 2 as the developing sleeve 2 rotates. A seal member 9 is provided in the collecting portion to allow the toner not consumed in the development to pass into the developing container 2 and prevent the toner 6 in the developing container 2 from leaking from the lower portion of the developing container 2. To prevent. The collected toner on the developing sleeve 2 is scraped off by elastic contact at the sliding contact portion between the supply roller 6 and the developing sleeve 2.

Most of the toner 6 scraped off is
The toner is conveyed as the supply roller 6 rotates, mixes with the toner in the developing container 2, and the charge of the charged toner is dispersed. At the same time, new toner is supplied onto the developing sleeve 2, and the elastic blade 3 and the developing sleeve 2 are again supplied.
Tribo is applied and the layer is thinned at the contact portion of the sheet, and the sheet is conveyed to the developing portion.

As described above, the undeveloped toner on the developing sleeve 2 that has not been consumed for the development is scraped off by the supply roller 6, so that the toner on the developing sleeve 2 is replaced and the toner is excessively charged, that is, charged up. Is prevented.

Next, the elastic blade 3 in this embodiment.
The positional relationship between the supply roller 6 and the supply roller 6 will be described in detail.

FIG. 11 is an enlarged view of the developing sleeve 2, the elastic blade 3 and the supply roller 6 in the vicinity of the abutting portion of the developing device in this embodiment. In this figure, the straight line v is
A vertical line passing through the sleeve rotation center (O ₁ )
Is a horizontal line passing through the sleeve rotation center (O ₁ ). Then, in the first quadrant of the coordinate space with these two straight lines as axes,
The contact portion of the elastic blade 3 with respect to the developing sleeve 2 is positioned. Also, the center of rotation of the supply roller 6 (O ₂ )
Are positioned below the center of rotation (O ₁ ) of the developing sleeve 2.

The angle θ is defined by a straight line passing through the most upstream point (point “D” in the figure) of the elastic blade contact portion and the developing sleeve rotation center (O ₁ ), and the most downstream point of the supply roller contact portion (point in the figure). It is an angle formed by "E") and a straight line passing through the developing sleeve rotation center (O ₁ ).

When the outer diameter of the supply roller 6 is R ₁ and the outer diameter of the developing sleeve 2 is R ₂ , the angle θ, the outer diameter R ₁ and the outer diameter R ₂ preferably satisfy the following conditions.

50 ° ≦ θ ≦ 80 ° (1) 0.7R ₂ ≦ R ₁ ≦ R ₂ (2)

Under these conditions, the toner sent from the developing container 5 is circulated by the rotation of the supply roller 6 and the developing sleeve 2 and the contact of the elastic blade 3 as shown by an arrow F in the figure. Do.

As a result, the toner that could not pass through the contact portion of the developing blade returns to the developing container side without immediately falling onto the supply roller 6, and therefore does not repeat the continuous circulation. The toner is not overloaded.

Further, by forming such a toner circulation, the replacement of new toner from the developing container side can be performed smoothly, so that the toner in the vicinity of the developing sleeve is blocked even in a high temperature and high humidity environment. Can be prevented.

Here, when the angle θ is θ <50 °, the toner that has not passed through the developing blade contact portion drops onto the supply roller 6 and immediately returns to the developing sleeve side. The toner is supplied and circulates in a small amount, which tends to cause changes in the physical properties of the toner. At this time, if R ₁ > R ₂ , the physical property changes further.

Further, when the angle θ is θ> 80 °, it is difficult for the toner to circulate as shown by the arrow F in FIG. 11, and as a result, toner blocking easily occurs near the developing sleeve. At this time, if R ₁ <0.7R ₂ , the blocking degree is further increased.

Even if the angle θ is 50 ° ≦ θ ≦ 80 °, if R ₁ > R ₂ , the toner supply in the developing sleeve direction becomes excessive when the toner remaining amount in the developing container is large. If R ₁ <0.7R ₂ , the toner supply failure to the developing sleeve 2 may occur when the toner remaining amount in the developing container is small. Therefore, the above conditions (1) and (2)
Are preferably satisfied at the same time.

Next, an experimental example conducted under the following conditions based on this embodiment will be described.

In this embodiment, an aluminum developing sleeve 2 having a diameter of 16 mm was used, and the surface was blasted with regular particles having a grain size of # 600 to have Ra of 0.5 to 1.0 μm and Rz.
Was roughened to 2.0 to 3.5 μm.

Next, as a material of the elastic blade 3, at least a contact portion with the developing sleeve 2 has a JIS hardness of 40 °.
A rubber of -80 °, preferably 50-70 ° is good for stable formation of a thin developer layer. Also, as the material,
Urethane, silicone, fluorine, neoprene, and various other rubbers can be used, but it is preferable that the toner used is far from the charging series to improve the charge amount of the toner.

In this embodiment, a silicon HTV rubber having a hardness of 60 ° is integrally molded on an end portion including a contact portion with the developing sleeve 2 on a SUS thin plate having a thickness of 0.06 mm.
Using a so-called chip blade, the contact pressure with the developing sleeve 2 is 5 to 30 g / cm, preferably 10 to 20 g / cm.
Set to. In the present embodiment, the "contact pressure" means that the contact portion is 2
The pull-out force per unit width when three 0 μm SUS thin plates are inserted and the central thin plate is pulled out with a spring pad. The abutting direction is counter abutting against the rotation of the developing sleeve 2, and the point D on the most upstream side of the abutting portion in the developing sleeve rotation direction is from the vertical line v passing through the rotation center O ₁ of the developing sleeve 2. It was positioned at a position inclined downward by 30 °.

In this embodiment, the material of the supply roller 6 is a sponge roller having a skeleton structure with a low degree of foaming, that is, a high density, more specifically, a urethane foam having a thickness of 5 mm (a density of 0.025 g / cm ³ ) Is formed on the core metal, and the outer diameter is 12 mm, that is, 0.75 of the diameter of the developing sleeve 2.
The doubled one was used. The sponge roller 6 softly abuts the developing sleeve 2, and the abutting width of 1 to 10 mm is effective, and it is 4 mm in the embodiment. In order to improve the peeling of the undeveloped toner on the developing sleeve 2, it is preferable that the peripheral speed of the sponge roller 6 and the peripheral speed of the developing sleeve 2 have a relative speed. ~ 600 mm / sec
Is effective, and in this embodiment, it is set to 150 mm / sec.

Further, the rotation direction of the supply roller 6 is the same as that of the developing sleeve 2, the position of the rotation center O ₂ of the supply roller 6 is positioned below the rotation center O _{1 of} the development sleeve 2, and the development sleeve 2 The position of the contacting portion with, that is, the position of the angle θ in FIG. 11, was set to θ = 60 °.

As the toner, a toner powder having an average particle diameter of 12 μm, which is composed of a copolymer of styrene / acrylic resin and styrene-butadiene resin, and a pigment, and colloidal silica 2.0.
% So-called one-component non-magnetic toner was used.

The developing method in this embodiment is, for example, the method described in JP-B-58-32375, that is,
An alternating current, in which a direct current is superposed, is applied between the photoconductor 1 and the developing sleeve 2 to transfer the thin layer toner on the developing sleeve 2 to the electrostatic latent image on the photoconductor 1 imagewise, that is, so-called " The non-contact developing method was used.

The developing device having the above-described structure was incorporated in an FC-2 copying machine manufactured by Canon Inc., and a bias power source was used in which a DC voltage of -300V was superimposed on an AC voltage of 1800Hz in frequency and 1200V in peak / peak voltage. The surface potential of the latent image on the photoconductor 1 was set to -600 V for the dark part and -150 V for the light part, and the distance between the developing sleeve 2 and the photoconductor 1 was set to 200 [mu] m to perform the non-contact development.

As a result, the developing sleeve 2 has about 30 μm.
A uniform coating layer of m was obtained, and the charge amount of this layer was measured by the blow-off method. As a result, the charge amount was +15 μc / g. This charge amount is sufficient to obtain a good image. The obtained image was a good image with a reflection density of 1.3.

Further, when 2,000 sheets of images were continuously formed, the charge amount of the toner was maintained at 15 to 20 μc / g, and a good image without density reduction and fog was formed until the final image formation. I was able to get

The present invention is not limited to the above-described embodiments, and for example, as the developer carrying member 2, a conductive elastic rubber roller is used instead of the developing sleeve, and the developer is brought into contact with the photosensitive member 1 to develop. You may employ the contact development method which performs. Also, not only AC + DC as the developing bias,
It is also possible to apply only a DC voltage.

Example 6 In this example, a one-component magnetic toner was used as a developer. According to the developing device of this embodiment, as shown in FIG. 12, the developing roller 2 includes a developing sleeve 2a and a magnet roller 2b held and fixed in the developing sleeve 2a.
And that the toner is conveyed by utilizing the magnetic force of the magnet roller 2b.
In other respects, it has the same configuration as the developing device of the fifth embodiment.

Further, in this embodiment, the magnetic force can be utilized also in the developing section, and in particular, by positioning one of the magnetic poles within the angle θ described in the above-mentioned Embodiment 5,
In the area, the spikes of the magnetic toner are formed, and as a result, the effect of improving the toner circulation efficiency and blocking can be enhanced.

Embodiment 7 This embodiment is different from the developing device of Embodiment 1 in that the supply roller 6 has a fur brush structure, and is otherwise the same.

That is, in this embodiment, the supply roller 6 is made of, for example, rayon fiber or the like, and the scraper 21 is arranged to prevent the toner clogging in the fur brush 6 with time. .

According to the developing device of this embodiment, each fiber of the fur brush 6 behaves independently at the contact portion of the developing sleeve 2, so that the toner is disturbed near the roller contact portion.
Swing is activated. As a result, the blocking prevention effect in the vicinity of the developing sleeve is further improved as compared with the case where a sponge is used as the roller material, and the latitude of the angle θ is widened.

As described above, according to the developing devices of Examples 5 to 7, a one-component developer is used to form a thin layer of toner and apply and strip toner by the developer regulating blade and the supply roller. By performing the configuration and further defining the positional relationship between the developer regulating blade and the supply roller with respect to the developing sleeve, it is possible to reduce the excessive load on the toner near the developing sleeve and prevent the toner clogging with a simple configuration. it can. This positional relationship is particularly effective when the rotation direction of the supply roller is in the same direction as the developing sleeve, and the outer diameter of the supply roller is 0.7 to 1.0 times the outer diameter of the sleeve. Then, the effect is further enhanced.

(Third Aspect of the Invention) As described with reference to FIG. 6, in the developing device using the non-magnetic toner, the developing roller is provided in the opening of the developing container 5 containing the non-magnetic toner 7, That is, the developing sleeve 2 is provided, and the developing sleeve 3
On the other hand, a supply roller 6 having a fur brush structure as a toner supply / separation member and an elastic blade 3 made of rubber or metal are in contact with each other.

The toner 7 in the developing container 5 is supplied to the supply roller 6
Is supplied to the developing sleeve 2, and is sent under pressure contact with the developing blade 3 as the developing sleeve 2 rotates. Here, the toner 6 is thinned and given sufficient tribo, and then developed in a portion facing the photoconductor 1, that is, a developing portion. After that, the toner 7 remaining on the developing sleeve 2 without being developed is peeled off by the supply roller 6 and the developing container 5 is removed.
The new toner 7 in the inside is again supplied to the developing sleeve 2 by the supply roller 6, and the above-described operation is repeated.

As a result, the non-magnetic toner 7 can be stably supplied onto the developing sleeve 2, a thin toner layer can be satisfactorily formed, the electrostatic latent image on the photoconductor 1 can be faithfully reproduced, and a high density wide area can be obtained. It became possible to develop a solid black image of satisfactorily.

In this developing apparatus, the supply roller 6 having a fur brush structure is used as the toner supply / separation member, but in addition to this, the supply roller is composed of an open-cell foam such as polyurethane foam having a foam skeleton structure. Is also commonly used, and due to the appropriate unevenness on the surface of the foam, it is possible to satisfactorily supply the toner to the developing sleeve and peel off the undeveloped toner in the same manner as the fur-roller structure supplying roller.

As described above, the structure in which the supply roller 6 is brought into contact with the developing sleeve 2 as the toner supply / separation member is effective not only when the non-magnetic toner is used but also when the magnetic toner is used. .

On the other hand, in the case of using the magnetic toner, since the toner is supplied to the developing sleeve 2 by the magnetic force of the magnet contained in the developing sleeve 2 as described above, the undeveloped toner on the developing sleeve 2 is used. It is difficult to remove the shavings sufficiently.

For this reason, among the toner thin layers formed on the developing sleeve 2, the toner which has been developed in the developing portion facing the photoconductor 1 and is then newly supplied onto the developing sleeve, and the developing portion. The undeveloped toner that has not been developed in 1. mixes on the developing sleeve, and a difference in developability between the two occurs, and uneven density is likely to occur.

Therefore, even when the magnetic toner is used, high image quality can be achieved by stripping the undeveloped toner by using the above-mentioned supply roller.

Further, in a developing device using a two-component developer consisting of toner and carrier, as shown in FIG. 18, development is carried out from a toner hopper 30 provided above the developing container 5 for accommodating only toner. Toner supply means 31 is required to supply a small amount of toner to the container 5 side. Conventionally, as the toner supply means, the toner replenishing roller 31 is formed of the above-described open-cell foam.

The toner supply roller 31 is used in the hopper 3
0 and the developing container 5 are arranged in the toner supply unit 32. The toner supply unit 32 has an opening 32 at two upper and lower positions.
A, 32B, that is, A is formed, and the toner replenishing roller 31 is formed.
Is rotatably disposed with its outer peripheral surface abutting on the pressing portions 32A and 32B. The toner replenishing roller 31 made of this foam contracts when passing through the pressing portion A,
Due to the expansion, the toner 6 in the hopper 30 is filled in the holes on the outer peripheral surface thereof, and at the time of contraction when passing through the downward pressing portion B, the toner 7 in the holes is discharged to a predetermined amount in the developing container 5. Supply toner.

The supplied toner 7 is sufficiently mixed with the developer composed of the toner and the carrier in the developing container 5 by the agitating means provided in the developing container 5, and the developing sleeve 2
And is conveyed to the developing unit facing the photoconductor 1 as the developing sleeve 2 rotates, and the electrostatic latent image is visualized.

As described above, conventionally, as the toner supplying means, the elastic supplying roller 6 which is made of a fur brush or an open-cell foam and supplies the toner by contacting the developing sleeve 2 is used. Alternatively, a toner replenishing roller 31 has been used, which is made of an open-cell foam and is provided at the opening of the hopper to supply the toner into the developing container.

However, in these rollers, especially when toner having a small particle size is used in a high temperature and high humidity environment, the toner gradually becomes clogged inside the roller during a large number of development operations, and the fur brush supply roller is fed. In the case of 6, the toner enters between the fibers, and in the case of the open-cell foam, since the air bubbles are in communication with each other, the toner enters the inside of the foam and causes the roller to be hardened. However, the inconveniences described in (1) above have occurred.

In the case of the supply roller contacting the developing sleeve The contact pressure of the supply roller 6 against the developing sleeve becomes excessive. The action of rubbing the toner on the developing sleeve is too strong, the toner is fused on the developing sleeve, the physical properties of the toner change (deteriorate), the fog increases, and the driving torque of the developing sleeve and the supply roller increases. To do. Also, since the degree of toner clogging in the supply roller becomes uneven in the longitudinal direction, unevenness occurs in the application and stripping of the toner on the developing sleeve by the supply roller, resulting in tribo and layer thickness of the thin toner layer on the developing sleeve. The unevenness occurs.

In the case of the toner replenishing roller provided in the opening of the hopper, since the elasticity of the toner replenishing roller 31 is remarkably reduced, the contraction and expansion of the pressing portions 32A and 32B become insufficient, and the toner replenishing roller 31 does not expand into the developing device. The toner supply amount is reduced, the developing density is lowered, and the driving torque of the toner supply roller is increased.

Inconvenience due to such hardened rollers,
In order to prevent this, conventionally, (a) a rubber skin layer is provided on the surface of the open-cell foam. (b) Use a cell foam. Etc. have been proposed.

However, the structure of the above (a), that is,
The following problems occurred when the rubber skin layer was provided on the surface of the open-cell foam.

(1) When this structure is adopted for the supply roller 6, the rubber skin layer rubs against the surface of the developing sleeve, so that the function of rubbing the toner onto the developing sleeve is too strong and the supplying roller is hard. When the developing operation is repeated a number of times, as in the case where the toner is changed, the toner is fused on the developing sleeve and the fog is increased due to the toner deterioration. Even when the surface of the skin layer is appropriately roughened, the hardness is locally higher than that of the surface of the foam, that is, the local pressure on the toner and the developing sleeve is high, and the same problem occurs.

(2) When this configuration is adopted for the toner replenishing roller 31, the toner is insufficiently filled in the holes on the outer peripheral surface of the roller at the time of contraction and expansion at the pressing portions 32A and 32B described above. Therefore, a certain amount of toner cannot be replenished into the developing container, and the sliding friction of the roller 31 on the pressing portions 32A and 32B with respect to the toner becomes excessive, so that the toner is deteriorated due to excessive pressure when the toner passes. invited. or,
Even when the skin layer surface is appropriately roughened, the toner replenishment was improved, but the above-mentioned toner deterioration could not be prevented because the local pressure was high.

On the other hand, the structure of the above (b), that is, by forming the rollers 6 and 31 with a foamed material having a single cell structure, the toner is applied to the developing sleeve, peeled off, and applied to the developing sleeve due to the appropriate unevenness of the roller surface. It is possible to satisfactorily replenish the toner and prevent the roller from being hardened due to toner clogging.

However, in the case of adopting the configuration of (b), it is necessary to pay sufficient attention to the influencing factors in order to perform a good function without any adverse effect.

According to the experiments conducted by the present inventors, the above-mentioned influencing factor for fully exerting the function of the roller is the rubber hardness of the foam, and conventionally, this factor was not taken into consideration. The following inconveniences have occurred.

That is, if the roller is made of a foam material having too high a rubber hardness, when the roller is used as the supply roller 6, the developing roller is arranged so as to surely abut against the developing sleeve. Also, as the contact pressure on the toner becomes too large, the torque increase similar to the case where the supply roller using the conventional open-cell foam is hardened, and the fogging increase phenomenon due to fusing of the developing sleeve and toner deterioration occurs. cause.

Also, when such a foam roller having a high rubber hardness is used as the toner replenishing roller 31, the contact pressure at the pressing portion becomes too large, the driving torque of the roller is remarkably increased, and the toner is slid on the toner. If the frictional force becomes excessively large, fog will increase due to toner deterioration.

On the other hand, if the roller is made of a foam having a too low rubber hardness, a large amount of the low molecular weight component of the rubber is contained in the foam, and the low molecular weight component of the rubber is applied as the developing operation and toner supply are repeated. It exudes and adheres to the object and the elasticity is significantly reduced. Therefore, when such a roller is used as the supply roller 6, the toner newly supplied onto the developing sleeve is provided with proper and sufficient tribo due to the adhesion (contamination) of the low molecular weight component of rubber to the developing sleeve. However, fogging occurs or the elasticity decreases, which causes a contact failure of the elastic roller with the developing sleeve, resulting in poor reproducibility of a solid black image due to insufficient toner supply and stripping. Even when it is used as a toner replenishing roller, a low molecular weight component of rubber adheres to the pressing portion, and toner adheres and accumulates on it, hinders toner replenishment, or reduces elasticity, and thus Contraction,
The expansion is insufficient and the toner cannot be satisfactorily replenished into the developing container, resulting in a low density.

In order to prevent such an adverse effect due to the exudation of the low-molecular weight component of the rubber, when a foam having a low rubber hardness in which the low-molecular weight component of the rubber is minimized is used, the tear strength is remarkably lowered and the roller Repeated use causes damage to the roller.

As described above, in the conventional developing device, when the rubber hardness of the foam is too high or too low, the function of the roller becomes insufficient and a defective image is generated. It occurred and was not preferable.

Therefore, according to the third aspect of the present invention, the toner supplying means is formed of a single foam foam rubber, and the rubber hardness of the foam rubber is 8 ° to 15 ° (asker).
By setting C), the developing device can be provided in which the function of the toner supply unit is fully exerted and the generation of a defective image that occurs when the rubber hardness is inappropriate.

Next, an example of the developing device according to the third aspect of the present invention will be described.

Embodiment 8 FIG. 16 shows an embodiment of the developing device according to the present invention. In this embodiment, the developing device has the same structure as that described above with reference to FIG. 1 and the like, and is formed on an image carrier that rotates in the direction of arrow a in the drawing, for example, the electrophotographic photosensitive member 1. The electrostatic latent image is developed into a visible image (toner image).

In this embodiment, the developing roller as the developer carrying member, that is, the developing sleeve 2 has a diameter of 16 as the base.
An aluminum sleeve of mm was used, and the surface thereof was blasted with glass beads (# 600) of a fixed shape to have a surface roughness Rz of about 3 μm.

The elastic blade 3 as the elastic regulating member is
As described above, the toner 7 that is pressed against the developing sleeve 2 and is in contact therewith, and the toner 7 that has entered between them under pressure is applied onto the developing sleeve 2 to form a thin layer of the toner 7.
The elastic blade 3 is formed of, for example, a rubber member such as silicone or urethane (the hardness specified by JISA is 40 ° to 90 °), and a part of the surface of the elastic blade 3 facing the developing sleeve 2 is in surface contact. And the developing sleeve 2 is pressed.

The contact pressure of the elastic blade 3 to the developing sleeve 2 in the present invention is preferably 5 to 200 g / cm in the linear pressure in the generatrix direction of the developing sleeve 2. In this embodiment, the elastic blade 3 has a hardness of 65 °, A urethane rubber blade having a thickness of 1.2 mm was used, and this blade was brought into contact with the developing sleeve 2 with a pressure contact pressure (linear pressure) of 50 g / cm.

In the same manner as described above, the linear pressure is measured by inserting three thin plates with known friction coefficients into the abutting portion between the elastic blade 3 and the developing sleeve 2 and by inserting the central thin plate. It was drawn out by a spring balance, and the drawing force at that time and the coefficient of friction were converted into the linear pressure.

Non-magnetic toner 7 used in this embodiment
Is used as a non-magnetic one-component developer, and is made by dispersing a pigment such as carbon in various thermoplastic resins such as styrene resin, acrylic resin and polyethylene resin. In this embodiment, as the toner 7, a toner powder having an average particle diameter of 8 μm, which is composed of a copolymer of styrene / acrylic resin and styrene / butadiene resin and a pigment, and externally added with 1.0% of colloidal silica is used. .

Next, the supply roller 6 as the developer supply / separation means will be described in detail.

As described above, the supply roller 6 strips off the toner 7 remaining on the developing sleeve 2 and supplies new toner 7.

In the present embodiment, the supply roller 7 has a metal cored bar 61 as a support shaft, and silicon rubber, EP
The OM rubber, CR rubber, and the like, in which the wall surface of the bubble portion communicates with the adjacent bubble portions and formed into a single-foam foam in the shape of a roller were used. Further, the surface of the supply roller 6 is rotationally driven in the direction of arrow c in the figure while being in pressure contact with the developing sleeve 2.

The present inventors conducted the following experiment in order to investigate the optimum range of rubber hardness. A silicone rubber foam having a rubber hardness (Asker C) of 5 °, 6 °, 8 °, 15 °, 17 °, and 20 ° was used, and a metal core 61 having an outer diameter of 5 mm was coated in a roller shape with a thickness of 5 mm. A supply roller 6 having an outer diameter of 15 mm was manufactured, incorporated into a developing device, and the developing device was installed in a copying machine FC-2 manufactured by Canon Inc. Under other conditions, the surface potential of the electrostatic latent image on the photoconductor 1 is set to the dark part -600.
V, bright part −150 V, a developing bias applied between the photoconductor 1 and the developing sleeve 2 was a frequency of 1800 Hz, and a peak-to-peak voltage of 1200 V was superimposed on a DC voltage of −250 V. While the process speed (peripheral speed) of the body 1 was 50 mm / s, the peripheral speed of the developing sleeve 2 was 70 mm / s, and the gap between the sleeve 3 and the photoconductor 1 was set to about 250 μm.

Table 1 shows the result of performing a copying operation of about 2000 sheets for each roller having different rubber hardness under this condition. In Table 1, toner 6 is fog at 2000 sheets.
Is due to the deterioration of the developing sleeve 3 or due to the adhesion of the low molecular weight component to the developing sleeve 3 after 2000 sheets have been developed.
After cleaning with the MEK, the image is printed. If the fog still occurs, it is determined that the toner 6 has deteriorated.
When the fog disappeared, it was judged that the low molecular weight component of the foam rubber adhered (contaminated) to the developing sleeve 3.

[0145]

[Table 1]

As is clear from Table 1, the rubber hardness is 5
When a foam of ° (Asker C) is used, a low molecular weight component of rubber adheres to the developing sleeve 2 to cause fog, and when a foam of rubber hardness of 20 (Asker C) is used, the toner 6 is applied. The contact pressure was excessive, the durability of the toner was deteriorated, and fogging occurred, which was not preferable.

Therefore, the usable range of the rubber hardness of the single-cell foam rubber forming the supply roller 6 is 6 ° to 17 °.
(Asker C), and the optimum range is 8 ° to 15 ° (Asker C). Within this range, adhesion of low molecular weight components of rubber and fogging due to toner deterioration do not occur at all, and the developing sleeve It is possible to stably and satisfactorily supply the toner 6 on the toner 2 and peel off the undeveloped toner 6 to obtain an image faithful to the electrostatic latent image on the photoconductor 1.

Embodiment 9 FIG. 17 shows a developing device according to another embodiment of the present invention.
In this embodiment, a flexible belt photosensitive member is used as the photosensitive member 1, and the developing sleeve 2 is in contact with the belt photosensitive member 1. This belt photoreceptor 1 is
For example, an OPC photosensitive layer is formed on the surface of a belt base layer such as polyethylene terephthalate (trade name Mylar) having aluminum vapor-deposited on the surface layer, and is driven to move in the direction of arrow a. In this embodiment, the peripheral speed of the belt photosensitive member 1 is about 50 mm / s, the developing sleeve 2 is faster than this, the peripheral speed is about 100 mm / s, and the toner on the developing sleeve 2 has a relative speed with the belt photosensitive member 1. The thin layer is rubbed, and tribo is positively applied to the toner 6 even at the contact portions on both sides.

In this embodiment, the bias applied to the developing sleeve 2 is DC (direct current) component only, and development is carried out by the potential difference with the belt photosensitive member 1.

Further, in the present embodiment, the developing sleeve 2
Since the belt photosensitive member 1 and the belt photosensitive member 1 are in contact with each other,
The usable range of the rubber hardness of the single-cell foam used as the supply roller 6 is expected to be narrowed, and the following experiment was conducted.

As in the case of Example 8, the rubber hardness of the silicone rubber foam was 5 °, 6 °, 8 °, 15 °, 17
When an image was formed using a material whose hardness was changed to 20 ° (Asker C), rubber hardness of 5 °, 6 °, which was low, was obtained.
When a foamed body of No. 1 is used, a low molecular weight component of rubber adheres to the developing sleeve 2 and is further transferred onto the photoconductor 1 so that the latent image on the photoconductor 1 is disturbed or the photosensitive layer on the photoconductor 1 is contaminated. However, new negative effects other than fog such as cracking occurred.

When a foam having a rubber hardness of 17 ° and 20 ° (Asker C) is used, the toner 6 on the developing sleeve 2 is used.
Since the rubbing against the toner is applied not only from the supply roller 6 but also from the photosensitive member 1, the toner is severely deteriorated and the toner is fused onto the developing sleeve 2.

When the photosensitive member 1 and the developing sleeve 2 are in contact with each other in this way, it is particularly necessary to keep the rubber hardness of the foam within the optimum range.

In the present embodiment, from the above results, the usable range of the rubber hardness of the foam forming the supply roller 6 is
8 ° to 15 ° (Asker C), and actually, Example 8
Usable range 6 ° to 17 ° (Asker C) when the photoconductor 1 and the developing sleeve 2 are not in contact with each other (the optimum range is 8
It is narrower than (15 °).

Although the present invention uses the non-magnetic toner in Embodiments 8 and 9, it can be applied to a one-component developing device using a magnetic toner by providing a magnet in the developing sleeve 2. However, other various modifications are possible within the scope of the present invention.

Embodiment 10 In the present invention, the toner replenishing roller 31 for replenishing toner from the toner hopper 30 into the developing container 5 by using the two-component developer composed of toner and carrier as shown in FIG. It can also be applied to a developing device provided.

According to this embodiment, the toner supply roller 31
Is formed of a single cell foam. The function of the toner replenishing roller 31 provided in the toner supply unit 32 of the toner hopper 30 and the developing operation are as described in the conventional example.

Also in this embodiment, the toner supply roller 3
Silicon foam is used as the foam forming 1
The rubber hardness (Asker C) was changed and the optimum range was investigated.

As a result, as in the case of Example 8, when a foam having a rubber hardness of 8 ° to 15 ° (Asker C) was used, the toner supply from the hopper 30 to the developing container 5 was stabilized for a long period of time. The image density can be maintained constant.

As described above, according to the present invention described in Embodiments 8 to 10, the roller-shaped toner supply means rotatably provided in the developing container containing the toner is used to form a single bubble. Made of body rubber, the rubber hardness of the foam is 8 °
By setting the angle to -15 ° (Asker C), it is possible to prevent adverse effects due to hardening due to toner clogging in the toner supplying unit, prevent problems caused when the rubber hardness of the foam is inappropriate, and to prevent the developing sleeve When it is used as an abutting elastic roller, it supplies and removes toner onto the developing sleeve in a stable manner, and even when it is used as a toner replenishing roller located at the hopper opening, toner is replenished to the developing device. Can be performed constantly and stably, and there is an effect that a good image can be stably obtained for a long period of time.

[0161]

As described above, in the developing device according to the first aspect of the present invention, the elastic regulating member is structured such that both longitudinal ends of the elastic regulating member are sandwiched between the seal member and the developer carrying member. The member is such that the tip end of the elastic regulation member at both end clamping portions is at least upstream with respect to the tip end of the elastic regulation member in the longitudinal container inwardly adjacent portion of the both end clamping portions of the elastic regulation member in the rotational direction of the developer carrying member. Since it is configured to be located on the side, it is possible to prevent the toner accumulated at the tip portion of the elastic regulation member from traveling along the tip portion and going to the nip portion at both longitudinal ends. Stable operation without leakage can be performed.

According to the developing device of the second aspect of the present invention,
A one-component developer is used, and an elastic regulating member for regulating the developer and a developer supply / peeling member are used to form a thin layer of toner, apply and strip toner, and further By defining the positional relationship between the regulation member and the developer supply / peel member, a simple configuration
It is possible to reduce the excessive load on the toner in the vicinity of the developer carrying member and prevent the toner from clogging. This positional relationship is
This is particularly effective when the rotation direction of the developer supply / peel member is the same as that of the developer carrying member, and the outer peripheral diameter of the developer supply / peel member is 0.7 to 1 of the outer peripheral diameter of the developer carrying member. ．
The effect will be further enhanced by setting it to 0 times.

According to the developing device of the third aspect of the present invention,
The roller-shaped toner supply means rotatably provided in the developing container containing the toner is formed of a single foam rubber, and the rubber hardness of the foam is 8 ° to 15 ° (Asker C).
By this, it is possible to prevent adverse effects due to hardening due to toner clogging in the toner supply means, prevent problems caused when the rubber hardness of the foam is improper, and bring the elastic roller into contact with the developer carrying member. When used as a toner supply roller, the toner is stably supplied and removed onto the developer carrying member, and even when used as a toner supply roller located at the hopper opening, the toner supply to the developing device is kept constant. It is possible to carry out stable operation, and there is an effect that a good image can be stably obtained for a long period of time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of a developing device according to the present invention.

FIG. 2 is a perspective view showing a relationship between a developing roller, a seal member, and an elastic blade.

FIG. 3 is a perspective view showing a relationship between a developing roller, a seal member, and an elastic blade according to another embodiment.

FIG. 4 is a perspective view showing a relationship between a developing roller, a seal member and an elastic blade according to still another embodiment.

FIG. 5 is a front view of one end of the elastic blade showing various modifications of the elastic blade.

FIG. 6 is a sectional view of a conventional developing device.

FIG. 7 is a cross-sectional view of a conventional developing device.

FIG. 8 is a perspective view showing a relationship between a developing roller, a seal member and an elastic blade of a conventional developing device.

FIG. 9 is a perspective view showing a relationship between a developing roller, a seal member and an elastic blade of a conventional developing device.

FIG. 10 is a sectional view of another embodiment of the developing device according to the present invention.

FIG. 11 is a cross-sectional view for explaining the operation of the developing device according to the present invention.

FIG. 12 is a sectional view of another embodiment of the developing device according to the present invention.

FIG. 13 is a sectional view of still another embodiment of the developing device according to the present invention.

FIG. 14 is a cross-sectional view of a conventional developing device.

FIG. 15 is a sectional view of a conventional developing device.

FIG. 16 is a sectional view of another embodiment of the developing device according to the present invention.

FIG. 17 is a sectional view of still another embodiment of the developing device according to the present invention.

FIG. 18 is a sectional view of a conventional developing device to which the present invention can be applied.

[Explanation of symbols]

1 image carrier (photoreceptor) 2 developer carrying member (developing roller) 3 elastic regulating member (elastic blade) 4 seal member 6 developer supply peeling member (toner supply roller)

Claims (3)

[Claims] 1. A developing container having an opening at a portion facing the image carrier and containing a one-component developer, and a developing container facing the image carrier carrying a latent image at the opening. A developer carrying member which forms a developing unit for supplying a component developer and carries and conveys the developer from the developing container to the developing unit, and a developer carrying member which is pressed against the surface of the developer carrying member and is applied to this surface. An elastic regulating member for regulating the amount of the developer, the length in the longitudinal direction of the elastic regulating member is longer than the developer supply opening of the developing container, but shorter than the developer carrying member, and In the developing device, which has a seal member between the developer carrying member and the developing container, and both longitudinal ends of the elasticity regulating member are sandwiched between the seal member and the developer carrying member, the elasticity regulating member. The clamping of both ends in the longitudinal direction of The tip end portion of the portion located upstream of the developer carrying member rotation direction is located at the upstream side of the developer carrying member rotation direction at least with respect to the tip end portion of the elastic restriction member adjacent to the nipping portion tip end portion. A developing device characterized by the above. 2. A developing container having an opening at a portion facing the image carrier and containing a one-component developer, and a developing container facing the image carrier carrying a latent image at the opening. A developer carrying member, which forms a developing unit for supplying a component developer, carries a developer from the developing container to the developing unit, and conveys the developer elastically to the developer carrying member, A rotatable developer supplying / releasing member for supplying the developer to the member and separating the developer, and the developer carrying member on the downstream side of the developer carrying member rotating direction of the developer carrying / releasing member. A developing device having a developer regulating member that abuts against the developer and regulates the layer thickness of the developer on the developer carrying member and imparts an electric charge to the developer. The axis is below the rotation center axis of the developer carrying member. And a contact portion of the developer regulating member with respect to the developer carrying member is located within a first quadrant of a coordinate space having a vertical line and a horizontal line passing through a rotation axis of the developer carrying member as axes. At the same time, a straight line passing through the most downstream point of the developer carrying member rotation direction of the contact portion of the developer supply / peeling member with respect to the developer carrying member and the rotation center of the developer carrying member, and the developer regulating member contact. The developer regulating member and the developing device are so arranged that an angle θ formed by the most upstream point of the rotation direction of the developer carrying member at the contact portion and a straight line passing through the rotation center of the developer carrying member is 50 ° ≦ θ ≦ 80 °. A developing device, wherein a developer supplying / releasing member is arranged with respect to the developer carrying member. 3. A developing container having an opening at a portion facing the image carrier and containing a developer, and a developer container facing the image carrier carrying a latent image at the opening. Development comprising a developer carrying member for carrying a developer from the developing container to the developing unit and carrying the developer, and a developer supplying unit for supplying the developer to the developer carrying member. In the apparatus, the developer supply means is formed of a single foam foam rubber, and the rubber hardness of the foam rubber is 8 ° to 15 ° (Asker C). .