JPH0256573A - Developing device - Google Patents

Abstract

PURPOSE:To improve the durability of a toner conveying member by pressing a toner conveyance member against a driving roller by a flexible belt guide at a part except an opposition part facing an image carrier and projecting the toner conveyance member to the image carrier side from the driving roller at the opposition part facing the image carrier. CONSTITUTION:The flexible belt guide 12 is extended along the outer periphery of the toner conveyance member 10 except the opposition part facing the image carrier 2 at both axial end parts of the toner conveyance member 10 provided to the outer periphery of the driving roller 9. Then this belt guide 12 is only tensed to press the conveyance member 10 against the driving roller 9 at the part except the opposition part facing the image carrier 2 and the driving roller 9 is projected to the image carrier 2 at the opposition part facing the image carrier 2. Consequently, even if the driving roller 9 deflects or becomes eccentricity, the deflection or eccentricity is absorbed by the deflection of the flexible belt guide 13 and the toner conveyance member 10 is used stably for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a developing device used in an electrophotographic device, etc., and in particular, a developing device that uses a one-component developer as a developer and develops the outer periphery of a drive roller. A toner conveying member provided so as to cover the surface of an image carrier such as a photoreceptor drum is brought into contact with the surface of the image carrier, and
The present invention relates to a developing device that applies toner to an image carrier from this toner conveying member.

[Prior art and its problems] Conventionally, in a developing device using a -component developer,
As disclosed in Japanese Patent Application Laid-Open No. 52-143831, non-magnetic toner is supplied to the surface of an elastic roller that conveys the toner, and this toner is pressed against the surface of the elastic roller by a toner regulating member such as a blade. , which charges the toner and regulates the thickness of the toner layer on the surface of the elastic roller.

Then, the surface of the elastic roller on which the toner layer of the required thickness has been formed is brought into contact with the surface of an image carrier such as a photoreceptor drum, and the toner is applied to the latent image portion formed on the surface of the image carrier. It is supposed to be done.

In such a developing device, since a toner regulating member such as a blade is brought into pressure contact with the surface of the elastic roller to charge the toner, the surface of the elastic roller is required to have relatively high hardness; In order to supply toner by bringing the surface of the elastic roller into contact with the surface of the image carrier, it is necessary to bring the surface of the elastic roller into soft contact with the surface of the image carrier throughout its axial direction. .

However, as mentioned above, it is very difficult to bring the surfaces of the elastic rollers, which have relatively high hardness, into soft contact with the surface of the image carrier in the entire axial direction, and the image carrier may be damaged. There were problems such as a decline in image quality.

In order to solve such problems, the present applicant disclosed a developing device (1,) as shown in FIG. 8 in a previous application.

In this developing device (11), a toner storage tank (3)
A sleeve-shaped member having a diameter larger than that of the drive roller (9) is used as the toner conveying member (10) for conveying the toner (4) contained in the toner (4) to the image carrier (2). 10) to cover the outer periphery of the drive roller (9).

A rigid guide member (121) formed in a semicircle having an inner diameter approximately the same as the outer diameter of the drive roller (9) is provided on both sides of the toner conveying member (10) in the axial direction, This guide member (12+) brings the toner conveying member (10) into pressure contact with the driving roller (9) at a portion excluding the facing portion facing the image bearing member (2), while also bringing the toner conveying member (10) into pressure contact with the driving roller (9) at a portion facing the image bearing member (2). At the facing part where the toner conveying member (
10) is protruded from the drive roller (9) toward the image carrier (2), and this protruded toner conveying member (10) is brought into soft contact with the surface of the image carrier (2), so that the image carrier ( 2
) The toner (4) was applied to the surface of the toner (4).

However, in such a developing device (11), the toner conveying member (10) is guided by a semicircular rigid guide member (12z) having an inner diameter that is approximately the same as the outer diameter of the drive roller (<6). The inner diameter of the guide member <12□) must be accurately matched with the outer diameter of the drive roller (6) in order to press the guide member (<12□) onto the drive roller (9) except for the facing part facing the image carrier (2). In order to avoid eccentricity or eccentricity, the accuracy of these central axes, etc., must be accurate, and manufacturing them has been extremely difficult.

If a misalignment occurs in the manufacturing of the guide member (121), drive roller (6), etc., the drive roller (9)
The torque applied to the toner conveying member (1
0), and the toner conveying member <10)
There was a problem in that the durability of the material decreased.

[Problems to be Solved by the Invention] The present invention has been made with an object of solving the above-mentioned problems.

That is, in the present invention, a toner conveying member having a diameter larger than that of the driving roller is pressed against the driving roller at a portion other than the facing portion facing the image carrier, and the toner conveying member is pressed against the driving roller at a portion excluding the facing portion facing the image bearing member. In a developing device in which a member is made to protrude toward the image carrier side from a drive roller, and the toner conveying member is brought into soft contact with the surface of the image carrier to apply I/toner, the toner conveying member is placed on the surface facing the image carrier. It is an object of the present invention to provide a developing device that can be easily and reliably brought into pressure contact with a drive roller at a portion other than the portion where the developing device is attached.

[Means for Solving the Problems] In the developing device according to the present invention, the drive roller is covered with a toner transport member having a diameter larger than that of the drive roller, and the image carrier is mounted on both sides of the toner transport member in the axial direction. A visible belt guide is provided on the outer periphery of the toner conveying member excluding the facing portion facing the image carrier, and this belt guide presses the toner conveying member against the drive roller at a portion excluding the facing portion facing the image carrier, and The toner conveying member is made to protrude toward the image carrier from the driving roller at the portion facing the carrier.

Here, as a flexible belt guide as mentioned above,
Polyester Polymer resin film with a thickness of about 20 to 200 μm made of synthetic resin such as polyethylene, polyacetate, polyimide, etc., or based on this polymer resin film, polytetrafluoride is applied to the surface that comes into contact with the toner transport member. Use a film laminated with a slippery film such as a fluororesin film made of ethylene or polyvinylidene fluoride.

[Operation] In the developing device configured in this way, flexible belt guides are arranged to face the image carrier on both sides in the axial direction of the toner conveying member provided so as to cover the outer periphery of the drive roller. By simply stretching this belt guide along the outer periphery of the toner-1 general conveying member excluding the facing part, the toner conveying member is pressed against the drive roller at the part excluding the facing part facing the image carrier. At the same time, at the facing portion facing the image carrier, the toner conveying member is projected toward the image carrier from the driving roller.

Furthermore, vibrations, eccentricity, etc. in the drive roller are absorbed by the deflection of the flexible belt guide.

Note that if you use a flexible belt guide that is based on a polymer resin film and has a slippery resin film stretched over the surface that comes into contact with the toner conveying member, the flexible belt guide will prevent the gap between the toner conveying member and the guide member. This improves the slippage and allows the toner conveying member to be driven smoothly.

[Example] Hereinafter, an example of the present invention will be specifically described based on the drawings.

First, an example of the developing device (1) shown in FIG. 1 will be described.

As shown in the figure, this developing device 1) has an image carrier (
2) is provided in a position close to the photoreceptor drum (2), and in a toner storage tank (3) provided at a rear position away from the photoreceptor drum (2), a -component type developer is installed. Toner (4), which is an agent, is stored therein.

Here, as shown in the figure, the toner storage tank (3) has a large first agitating portion located at the rear, away from the photoreceptor drum (2), by a mountain portion (3a) provided at the bottom of the toner storage tank (3). (5) and a small second stirring section (6) located closer to the photoreceptor drum (2) than the first stirring section (5). Part (5), (
6) is provided with first and second stirring members (7) and (8) for stirring the toner 4), respectively.

Then, the first stirring member (7) provided in the first stirring part (5) is rotated to stir the toner (4) in the first stirring part (5), and the toner (4) is stirred in the second stirring part (5). Stirring part (6)
It is supposed to be sent to

Further, the toner (4) thus sent to the second stirring section <6) is further rotated by the rotation of the second stirring member (8) provided in the second stirring section <6). It is designed to be stirred.

The photoreceptor drum (2) is then accessed from the toner storage tank (3).
) side is provided with a toner conveying member (10) driven by a drive roller (9), and the toner (4) stirred in the second agitating section (6) is transferred to the toner conveying member (10). It is adapted to be supplied to the surface of the member (10) by contact or electrostatic force.

Here, the drive roller (9) may be one made of a conductive member such as aluminum or stainless steel, or one made of a conductive material such as aluminum or stainless steel, or a base body formed in a cylindrical shape with a conductive layer or a conductive rubber layer provided on the outer peripheral surface. things etc. are used.

This driving roller (9) is connected to the photosensitive drum (2).
It is rotatably housed in the vicinity of the opening (11) of the developing device (1) facing the photoreceptor drum (2), and the photoreceptor drum (2) is rotated by a motor (not shown). ) is designed to rotate in the opposite direction.

On the other hand, the toner conveying member (10) is connected to the drive roller (9).
), and the toner conveying member (10) is provided so as to cover the outer periphery of the drive roller (9).

And in this example, the visible belt guide (12
) is made of a polymer resin film (12a), and this belt guide (12>) is connected to the photoreceptor drum (
The upper end of the belt guide (12) is pulled along the outer periphery of the toner conveying member (10) excluding the facing portion facing the developing device (1).
) and attach it to the front part of the belt guide (12).
The lower end of the toner conveying member (10) is attached to the bottom of the developing device (1), and the toner conveying member (10) is brought into pressure contact with the outer peripheral surface of the drive roller (9) at a location other than the facing portion facing the photosensitive drum (2). I have to.

In addition, in this way, the toner conveying member 10) is connected to the drive roller at a location other than the facing portion facing the photosensitive drum (2).
When the toner conveying member 10) is brought into pressure contact with the outer circumferential surface of the drive roller (9), the extra length of the toner conveying member 10), which is longer than the drive roller (9), is pressed against the outer peripheral surface of the drive roller (9).
9) protrudes toward the photoreceptor drum (2) side, and this protruding toner conveying member (10) comes into contact with the surface of the photoreceptor drum (2).

When the drive roller (9) rotates in this state, the drive roller (9) is rotated by the belt guide (12).
The toner conveying member (10) pressed against the drive roller (
Due to the frictional force with the drive roller (9), it is driven as the drive roller (9) rotates. In this case, even if there is vibration or eccentricity in the drive roller (9), the belt guide <12) absorbs this, and the torque applied to the drive roller (9) increases or the toner conveying member (10) No more force than necessary is applied to the

The toner conveying member (10) is driven in this way, and the toner (4) supplied to the surface of the toner conveying member (10) is transferred to the drive roller (9).
) is pressed by a small diameter round rod (14) provided at the tip of the blade (13),
The toner is applied thinly and uniformly to the surface of the toner conveying member (10) and is charged by friction.

Thereafter, the conveying members 1 to 10 (10) are further driven as the drive roller (9) rotates, and are guided to the facing portion facing the photoconductor drum 2), and the photoconductor The photoreceptor drum (2) protrudes toward the drum (2) side.
) to sufficiently and softly contact the surface of the photoreceptor drum (2) to apply toner (4 toner) to the surface of the photoreceptor drum (2).

Here, in the one shown in FIG. 2, the side portions of the blade (13) and the round bar (14) which press the toner (4) supplied to the surface of the toner conveying member (10) are cut out, Attach the bell I guide (12) below the notch.
), and the blade (13) and round bar (14) are
The toner (4) can be pressed into contact with the belt guide (12) without being obstructed by the belt guide (12).

In addition, in the device shown in FIG. 3, the blade (13) and the round bar (14) that press the toner (4) supplied to the surface of the toner conveying member (10) are used, similarly to the device shown in FIG. ) and place the belt guide (12) under this notch.
) and the round rod (14>), the belt guide (12) is provided with a toner suppressing portion (12c) that protrudes inward.

The toner suppressing portion (12c) allows the toners 1 to (4) supplied to both sides of the toner conveying member (10) to pass through the gap between the blade 13) and the belt guide <12). This is to prevent the liquid from spilling onto the photoreceptor drum (2) side.

Further, in the embodiment shown in FIG. 4, the belt guide (12) moves the toner conveying member (10) to the drive roller (9) at a location other than the facing portion facing the photoreceptor drum (2). To press the belt guide (12) against the outer circumferential surface, the belt guide (12) is placed along the outer circumference of the toner conveying member (10) except for the portion facing the photoreceptor drum (2), and this belt guide (
12) Attach the lower end of the belt guide (12) to the bottom of the developing device (1), and while the upper end of the belt guide (12) is pulled, use the biasing means (15) such as a spring to rotate the developing device (1). It is attached to the front part.

Then, when the belt guide (12) pulled by the biasing means (15) such as a spring brings the toner conveying member (10) into pressure contact with the outer peripheral surface of the drive roller (<9), the drive roller ( 9) are more efficiently absorbed by the expansion and contraction of the biasing means (15), preventing large torque from being applied to the drive roller (9) or excessive force from being applied to the toner conveying member (lO). It will be possible to more effectively suppress the

Further, in the embodiments shown in FIGS. 5 to 7, a belt is used that presses the toner conveying member (10) against the outer circumferential surface of the drive roller (9) at a location other than the facing portion facing the photosensitive drum (2). A polymer resin film (12a) is attached to the guide (12).
) and one side of which is laminated with a slippery film (12b) such as fluororesin film or film.

Then, the slippery film (12b) of this belt guide (12) is brought into contact with the toner conveying member (10), and as in the case of FIG. On both sides of the member (10) in the axial direction, pull the belt guide (12) along the outer periphery of the toner conveying member (10) excluding the facing portion facing the photoreceptor drum (2). ) is brought into pressure contact with the outer circumferential surface of the drive roller (9) at all locations except for the facing portion facing the photoreceptor drum (2).

In this way, in the belt guide (12), the slippery film (12b) is brought into contact with the toner conveying member (10>), and the toner conveying member (10) is moved to the driving roller (9).
), the belt guide (
12) and the toner conveying member (10),
Toner conveying member (10) accompanying rotation of drive roller (9)
The driving of the toner conveying member (10) is reduced, and the force applied to the toner conveying member (10) between the belt guide (12) and the drive roller (9) is reduced.
0) durability is improved.

In addition, in this embodiment, similarly to the one shown in FIG. A belt guide (12) is placed under the notch, and the blade (13)
At a position closer to the toner feed side than the round bar <14>, there is a toner suppressing portion (12) protruding inward from the belt guide (12).
c).

Then, this toner suppressing part (12c) is extended longer toward the blade <13) than the one shown in FIG. The toner (4) supplied to both sides of the member (10) is applied to the blade (13) and the belt guide (1).
This prevents the liquid from spilling out to the photosensitive drum 2) through the gap between the photosensitive drum 2) and the photosensitive drum 2).

[Effects of the Invention] As detailed above, in the developing device according to the present invention, flexible belt guides are provided on both sides in the axial direction of the toner conveying member provided so as to cover the outer periphery of the drive roller. , by simply tensioning the belt guide along the outer periphery of the toner conveying member excluding the facing portion facing the image carrier, the toner conveying member is brought into pressure contact with the drive roller at the portion excluding the facing portion facing the image bearing member. In addition, the portion facing the image carrier can be made to protrude from the drive roller toward the image carrier.

As a result, as in the past, the drive roller and the semicircular guide member having an inner diameter that is approximately the same as the outer diameter of the drive roller,
It is now possible to easily and reliably press the toner conveying member against the drive roller without having to manufacture it extremely precisely so that the diameter, center, etc. do not go out of order.

Furthermore, even if vibration or eccentricity occurs in the drive roller, the vibration or eccentricity of the drive roller is absorbed by the deflection of the flexible belt guide that presses the toner conveying member against the drive roller. As a result, the toner conveying member is not damaged due to large torque being applied to the drive roller or excessive force being applied to the toner conveying member, and can be used stably for a long period of time.

Furthermore, if a slippery resin film is used as the visible belt guide on the surface that comes into contact with the toner transport member, the toner transport member and the guide member will slip more easily and the toner transport member will not be driven. This allows the toner conveying member to be used stably for a longer period of time.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing the inside of a developing device according to an embodiment of the present invention, and FIG. 2 is a partial perspective view showing an example of a state in which a belt guide is disposed on the side of a toner conveying member in the same embodiment. , FIG. 3 is a partial perspective view showing an example of a change in the state in which the belt guide is disposed on the side of the toner conveying member in the same embodiment, and FIG. FIGS. 5 to 7 are partial schematic sectional views showing examples of state changes, and FIGS. 5 to 7 show developing devices according to other embodiments of the present invention. FIG. 6 and 7 are a partial perspective view and a partial cross-sectional view of a belt guide arranged on the side of a toner conveying member, and FIG. 8 is a partial schematic cross-sectional view showing the inside of a conventional developing device. (1)...Developing device, (2)...Image carrier (photosensitive drum), (9>...Drive roller, (10)...
...Toner conveying member, (12)...Belt guide. Patent applicant: Minolta Camera Co., Ltd. Figure 2 Figure Z Figure Z

Claims (1)

[Claims] 1. The drive roller is covered with a toner conveyance member having a diameter larger than that of the drive roller, and on both sides of the toner conveyance member in the axial direction, the outer periphery of the toner conveyance member, excluding the facing portion facing the image carrier, is flexible. A belt guide is provided, and this belt guide presses the toner conveying member against the driving roller at a portion excluding the facing portion facing the image carrier, and also presses the toner conveying member against the driving roller at the portion facing the image bearing member. A developing device characterized by projecting toward an image carrier.