JPH01164979A - Developing device for electro-photographic device - Google Patents

Abstract

PURPOSE:To prevent a toner from being blown off by generating a sealing function at the separating plane of a guide member by abutting the napping of a developer formed at the outer peripheral part of a magnet roll by a magnetizing part with the separating plane of the guide member. CONSTITUTION:The guide member 35 is provided at the downstream side of a developer regulating member 34 in such a way that the upstream side part of the confronting plane with the magnet roll 32 is separated than the downstream side part, and the magnetizing part S is provided or a part corresponding to the separating plane 35a in the magnetic roll 32. In the carrying process of the developer, the amount of the developer being attracted on the outer peripheral part of the magnet roll 32 is regulated. At this time, at the downstream side of the developer regulating member 34 in the carrying direction of the developer, pressure drops, and the toner is blown off from the developer regulating member 34 at the downstream side. However, since the napping 36 of the developer formed at the outer peripheral part of the magnet roll 32 by the magnetizing part S is abutted with the separating plane 35a of the guide member 35, the toner is sealed and is prevented from being blown off.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device for an electrophotographic apparatus such as an electrostatic transfer copying machine.

[Conventional technology]

Conventionally, an electrophotographic apparatus such as an electrostatic transfer copying machine is equipped with a developing device 1, as shown in FIG.
Toner supplied from the upper toner transport box 2 is stirred and mixed with a carrier such as iron powder by stirring rollers 3 and 4, and is sent to a magnet roller 5 as a developer. This magnet roller 5 includes, for example, three main poles N1, N2, and N that are magnetized parts, and two main poles that are provided between these main poles N1 to N3 and that assist the developer to be transported smoothly. It has commutative poles S1 and S2. The main poles N1 to N3 and the subpoles S1 and S2 attract and transport the developer to the outer circumference of the magnetic roller 5, and the magnetic brush formed by the main pole N1 transfers the toner to the photoreceptor drum 6. supply.

Further, a doctor 7 as a developer regulating member is provided above the magnet roller 5, and a D2 cover (developer cover) 8 is provided on the side of the doctor 7 in the developer transport direction.

The tip of the doctor blade 7 is close to the outer periphery of the magnet roller 5, and controls the amount of developer attracted to the magnet roller 5 so that an appropriate amount of developer is conveyed.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional structure, toner blows out from the tip of the doctor 7 toward the DV cover 8 due to a pressure drop on the downstream side of the doctor 7 in the developer transport direction, that is, on the DV cover 8 side. do. Since the toner here is a dynamic powder, it is not held between the DV cover 8 and the magnet roller 5, and is ejected to the outside. Therefore, there is a problem that toner cannot be appropriately supplied to the photoreceptor drum 6.

[Means for solving problems]

In order to solve the above problems, a developing device for an electrophotographic apparatus according to the present invention includes a stirring roller that stirs and mixes toner and carrier and supplies the mixture as a developer to a magnetic roller, a main pole, and a main pole. It has each magnetized part as a complementary pole which has a different polarity from the main pole, and these magnetized parts attract the developer to the outer circumferential part to form a magnetic brush, thereby supplying the developer to the photoreceptor. An electronic device comprising a magnetic roller, a developer regulating member that regulates the amount of developer attracted to the outer circumference of the magnetic roller, and a guide member provided downstream of the developer regulating member in the developer transport direction. In the developing device of a photographic device, the surface of the guide member facing the magnet roller forms a separation surface in which the upstream portion in the developer conveyance direction is farther from the magnet roller than the downstream portion, and the downstream side The portion forms a proximate surface that is close to the magnet roller, and the proximal surface is formed so that the gap between the magnet roller and the magnet roller is approximately uniform over a predetermined length in the developer transport direction. A magnetized portion is provided at a portion corresponding to the separation surface of the guide member, and the spikes of developer formed on the outer peripheral portion of the magnet roller are brought into contact with the separation surface by the magnetization portion.

[For production]

According to the above configuration, the toner and carrier are stirred and mixed by the stirring roller and supplied as a developer to the magnet roller, and the developer supplied to the magnet roller is attracted to the outer circumference of the magnet roller by the magnetized portion. transported. During the developer transport process, the developer regulating member regulates the amount of developer attracted to the outer peripheral portion of the magnetic roller. At this time, a pressure drop occurs on the downstream side of the developer regulating member in the developer transport direction, and toner is blown out downstream from the developer regulating member. However, this toner is sealed by the spikes of developer formed on the outer periphery of the magnet roller by the magnetized portion coming into contact with the separated surface of the guide member, and the blowing out of the toner is suppressed. Furthermore, the surface of the guide member facing the magnet roller forms a separation surface in which the upstream portion in the developer transport direction is farther from the magnet roller than the downstream portion, so that the separation surface and the magnet roller are separated from each other. An air pocket is formed in the gap, and the blown toner becomes a turbulent flow, and the blowing force is suppressed. In addition, the downstream portion forms a proximate surface that is close to the magnet roller, and this proximal surface is formed so that the gap with the magnet roller is almost uniform over a predetermined length in the developer conveyance direction. , the space between the proximal surface and the magnet roller functions as a sealing portion to prevent toner from blowing out.

〔Example〕

An embodiment of the present invention will be described below based on FIGS. 1 to 3.

As shown in Figure 2, a copying machine, which is an electrophotographic device, has
The developing device 21 is provided with a toner box 23 which is a toner supply source containing toner, and a toner transport box 24 which supplies the toner sent from the toner box 23 to the developing device 21 while reciprocatingly transporting the toner. A toner hopper 22 is provided.

The toner box 23 has a toner stirring shaft 25 that stirs the toner inside, and a toner supply screw 26 that transports the toner and feeds it into the toner transport box 24 . On the other hand, the toner transport box 24 includes a pair of toner transport screws 27 and 28 that are parallel to each other and rotate in opposite directions at the same rotation speed to circulate and uniformize the toner inside. A toner replenishing roller 29 made of sponge is provided in parallel with these toner conveying screws 27 and 28, and supplies toner in the toner conveying box 24 to the developing device 21 through a long hole 24a formed in the lower wall when rotated. have.

Further, the developing device 21 produces a developer by stirring and mixing the toner supplied from the toner transport box 24 and a carrier made of iron powder, etc., and supplies this developer to the magnetic roller 32. Roller 30/31
and a magnet roller 32 that adsorbs the developer supplied from these stirring rollers 30 and 31 on its outer peripheral portion, conveys it, and supplies it to the photoreceptor drum 33.

The above magnet roller 32 has three main poles N.

・N!・N3, and two subpoles S1 and S2 that assist the developer to be transported smoothly, and these main poles N, ~N3 and subpoles S, -S2 are located at the magnetized portion, respectively. It consists of The above-mentioned subpole S1 is arranged between the main poles N1 and N2, the subpole S2 is arranged between the main poles N and N1, and the main pole N1 is arranged at a position corresponding to the photoreceptor drum 33, and the subpole S2 is arranged between the main poles N and N1. S
1 is arranged at a position corresponding to the separation surface 35a of the DV cover 35. Further, the magnet roller 32 has a rotatable sleeve (not shown) on its outer circumference. Then, the main poles N, -N and subpoles S+-SZ adsorb the developer onto the outer peripheral surface of the sleeve and convey it to the photoreceptor drum 3.
Toner is supplied to 3.

A doctor 34, which is a developer regulating member, is provided above the magnet roller 32. The tip of this doctor 34 protrudes downward and connects the magnet roller 32.
The magnetic roller 32 forms a regulating portion 34 a that regulates the amount of developer attracted to the magnetic roller 32 .

Between the doctor 34 and the photosensitive drum 33, that is, on the downstream side of the doctor 34 in the developer transport direction, a guide member D is provided along the outer circumference of the magnet roller 32.
A V cover 35 is provided. The lower surface of this DV cover 35 is curved to have an arcuate cross section along the outer circumference of the cylindrical magnet roller 32. The upstream portion of the curved lower surface in the developer conveying direction has a large diameter from the center of the magnet roller 32 .
The downstream portion has a smaller diameter from the center of the magnet roller 32 and is a proximal surface 35b that is close to the magnet roller 32.

Therefore, the gap between the proximal surface 35b and the outer peripheral portion of the magnet roller 32 is uniform in the developer conveying direction, that is, in the length direction of the proximal surface 35b. Note that the diameter of the proximal surface 35b centered on the center of the magnet roller 32 is as small as possible without coming into contact with the developer, the more the toner scattering prevention function described below can be improved. Furthermore, D
A spacing surface 35a on the lower surface of the V-cover 35 is brought into contact with a spike 36 formed by the developer being attracted to the outer circumferential portion of the magnet roller 32.

In the above configuration, when the amount of toner in the toner transport box 24 falls below the appropriate value, the toner supply screw 26 in the toner box 23 rotates, as shown in FIG. It is supplied to the transport box 24. At the same time, the toner conveyance screws 27 and 28 rotate, and the supplied toner is conveyed back and forth within the toner conveyance box 24 and evenly supplied into the toner conveyance box 24.

On the other hand, when the toner concentration in the developing device 21 falls below the appropriate value, the toner replenishing roller 29 in the toner transport box 24
The toner conveyance screws 27 and 28 rotate, and the toner supply roller 29 supplies the developing device 2 through the elongated hole 24a.
Toner is replenished to 1.

The toner supplied to the developing device 21 is transferred to the stirring roller 30.
The developer is stirred and mixed with the carrier by the developer 31, and sent to the magnet roller 32 as a developer. The developer sent to the magnet roller 32 is distributed between main poles N1 to N, subpoles S, .
S2, the magnetic roller 32 is attracted to the outer peripheral surface of the sleeve of the magnetic roller 32. At this time, the main pole N, ~N3 and the complementary pole S, -
The developer is concentratedly attracted to the portion corresponding to S2, and the spikes 36 protrude in the radial direction of the magnet roller 32.
is formed. When the sleeve rotates, the developer is conveyed together with the sleeve toward the photosensitive drum 33. In this process, the amount of developer on the sleeve is regulated by the regulating portion 34a of the doctor 34, and an appropriate amount of developer is conveyed.

Here, a pressure drop occurs in a portion on the developer conveying direction side from the doctor 34, that is, in the gap between the separation surface 35a of the DV cover 35 and the magnet roller 32, and the pressure drop occurs between the regulating portion 34a of the doctor 34 and the magnet roller 32. Toner is blown out in the direction of the DV cover 35 from between.

However, since spikes 36 are formed on the outer circumferential surface of the sleeve on the commutating pole S1 of the magnet roller 32, and the spikes 36 are in contact with the separation surface 35a, the blown toner is blown out from the spikes 36. This seals the air and prevents it from blowing out. Furthermore, even if the toner passes through the seal of the stander 36 and blows out, the gap between the separating surface 35a and the magnet roller 32 is the same as the gap between the adjacent surface 35b and the magnet roller 32 on the downstream side of this gap. By being wider than the gap, the gap on the side of the separation surface 35a becomes an air pocket, and the toner blown out from the doctor 34 causes turbulence in the air pocket, making it difficult for the toner to blow out. Further, since the gap formed by the proximal surface 35b is formed to have a uniform width over a predetermined length, it functions as a sealing portion and reliably prevents toner from blowing out.

〔Effect of the invention〕

As described above, the developing device of an electrophotographic apparatus according to the present invention includes a stirring roller that stirs and mixes toner and carrier and supplies the mixture as a developer to a magnetic roller, a main pole, and a polarity different from the main pole. The magnetic roller has magnetized parts that serve as commutating poles, and these magnetized parts attract the developer to the outer periphery to form a magnetic brush, thereby supplying the developer to the photoreceptor. A developing device for an electrophotographic apparatus, comprising a developer regulating member that regulates the amount of developer adsorbed on the outer circumference of a roller, and a guide member provided downstream of the developer regulating member in the developer transport direction. In,
The surface of the guide member facing the magnet roller forms a separation surface in which the upstream portion in the developer transport direction is farther from the magnet roller than the downstream portion, and the downstream portion is closer to the magnet roller. This proximity surface is formed so that the gap with the magnet roller is almost uniform over a predetermined length in the developer conveying direction, while the magnet roller has a gap with the separation surface of the guide member. The magnet roller has a magnetized portion at a corresponding portion, and the developer spikes formed on the outer peripheral portion of the magnet roller are brought into contact with the separation surface by the magnetized portion. - Therefore, even if a pressure drop occurs on the downstream side of the developer regulating member in the developer transport direction and toner blows out downstream from the developer regulating member, the guide member will not be separated. Since the spikes of developer formed on the outer periphery of the magnetic roller by the magnetized portion are in contact with the surface, a sealing function is generated at this portion, and the blowing out of toner is suppressed. Furthermore, an air pocket is formed in the gap between the separating surface of the guide member and the magnet roller, and the blown toner becomes a turbulent flow, the blowing force is suppressed, and the gap between the proximal surface of the guide member and the magnet roller becomes turbulent. It functions as a seal and prevents toner from blowing out. Therefore, the sealing function of each part prevents the toner from blowing out to the outside, and the developer can be appropriately supplied to the photoreceptor.

[Brief explanation of the drawing]

1 to 3 show one embodiment of the present invention, in which FIG. 1 is a vertical sectional view showing the internal structure of the developing device, and FIG.
The figure is a vertical sectional view showing the internal structure of the toner hopper and the developing device, FIG. 3 is an explanatory perspective view showing the flow of toner in the toner hopper shown in FIG. 2, and FIG. 4 is a conventional example. FIG. 2 is a vertical cross-sectional view showing the internal structure of the developing device. 21 is a developing device, 22 is a toner hopper, 30 and 31 are stirring rollers, 32 is a magnet roller, 33 is a photoreceptor drum (photoreceptor), 34 is a doctor (developer regulating member),
34a is a regulating portion, 35 is a D■ cover (guiding member), 35
a is a separation surface, 35b is a proximal surface, and 36 is a spike. Figure 1 Figure 3

Claims (1)

[Claims] 1. A stirring roller that stirs and mixes toner and carrier and supplies the mixture as a developer to a magnetic roller, a main pole, and each magnetized pole as a complementary pole having a different polarity from the main pole. a magnetic roller which supplies the developer to the photoconductor by attracting the developer to the outer circumference of the magnetic brush to form a magnetic brush; and a developer which is attracted to the outer circumference of the magnetic roller. In a developing device of an electrophotographic apparatus, which includes a developer regulating member that regulates the amount of developer, and a guide member provided downstream of the developer regulating member in the developer transport direction, the magnet roller of the guide member and the guide member are provided. The opposing surfaces of the developer are configured to form a separation surface in which the upstream portion in the developer transport direction is further away from the magnet roller than the downstream portion, and to form a proximal surface in which the downstream portion is closer to the magnet roller. The proximal surface is formed so that the gap with the magnet roller is almost uniform over a predetermined length in the developer transport direction, while the magnet roller has a magnetized portion at a portion corresponding to the separating surface of the guide member. 1. A developing device for an electrophotographic apparatus, wherein spikes of developer formed on the outer periphery of the magnet roller by the magnetized portion are brought into contact with the separating surface.