JPH034258A - One-component developing device - Google Patents

Abstract

PURPOSE:To prevent printing blur and fog and to improve the development characteristic by providing a developing unit with a driving source which drives a developing roller. CONSTITUTION:The driving source 11 is provided on the developing unit 2, and positional relations between the driving source 11 and the developing roller 7 of the developing unit 2, etc., are fixed irrespective of the moving operation of the developing unit 2. Moment produced by the drive of the driving source 11 is not applied to the entire developing unit 2, but is processed in the inside of the unit 2, therefore the pressure of the developing roller 7 does not vary even if driving load torque varies. Since the positional relations are fixed and all moments in the axial direction are processed in the unit 2, horizontal pressure in the axial direction of the developing roller 7 is uniformized, and an extra auxiliary means is not required.

Description

[Detailed description of the invention] [Table of contents] Overview Industrial field of application Prior art (Figure 7) Means for solving the problem to be solved by the invention (Figure 1) Working example (a) Section Explanation of the first embodiment (Figures 2, 3, and 4) (b) Explanation of the second embodiment (Figure 5) (C) Explanation of the third embodiment (Figure 6) ( d) Description of other embodiments Effects of the invention [Summary] Regarding a single-component developing device that uses a single-component toner and develops the image by pressing the developing roller against the image bearing member, the variation in the overall developing pressure due to the driving of the developing roller can be reduced. In order to prevent this, a developer unit is provided with a developing roller for supplying monocomponent toner to an image carrier on which an electrostatic latent image is formed, and the developer unit is biased toward the image carrier. In the one-component developing device including a biasing means for pressing the developing roller against the image carrier, a driving source for driving the developing roller is provided in the developing unit.

[Industrial application field]

The present invention relates to a one-component developing device that uses one-component toner and develops the image by pressing a developing roller against an image carrier.

A single-component developing device performs development using a single-component toner, and can be easily maintained and made compact.

In such a one-component developing device, it is necessary to perform development by pressing the developing roller against the image carrier, and it is necessary that the pressure be uniform and constant in order to obtain good development characteristics.

[Conventional technology]

FIG. 7 is an explanatory diagram of the prior art.

In the one-component developing device, as seen in Japanese Patent Laid-Open No. 46-86819, a developing unit 2 having a developing roller 7 is attached to a photosensitive drum 1 as an image carrier using a biasing means 10 such as a spring. Developing is performed by pressing the developing roller 7 against the photosensitive drum 1 with appropriate pressure.

The developing unit 2 is movable relative to the photosensitive drum 1, and is configured to always come into contact with a constant pressure by a biasing means 1O against eccentricity of the photosensitive drum 1.

By the way, the drive source (
The motor II has conventionally been provided outside the developing unit 2 and drives the developing roller 7 and the like via a power transmission mechanism such as a gear.

In such a conventional drive system, since the drive is performed from one side and from the outside, an axial moment is generated, the developing unit 2 rotates, and the axial pressure distribution of the developing roller rough becomes uneven.

For this reason, conventionally, as shown in FIG. 7(B), a structure has been used in which the shaft 70 opposite to the driving side of the developing roller 7 is pressed in the direction of the photosensitive drum 1 with a lever L. ), drive gears 71 and 72 are provided on both sides of the drive shaft 70 of the developing roller rough, and the driving force of the drive source 11 is transferred to the auxiliary shaft 110.
A device is used that transmits the image using gears 111 and 112 provided on both sides of the developing roller and drives both sides of the developing roller (such as Japanese Utility Model Publication No. 62-63758).

[Problem to be solved by the invention]

Incidentally, the driving load torque tends to fluctuate due to fluctuations in the amount of developer in the developing unit 2 and bearing wear.

In particular, since the developing unit 2 is configured to be movable, the positions of the drive source 11 fixed to the apparatus and the movable developing unit 2 are likely to fluctuate. The moment force applied to 2 itself changes, and the overall developing pressure (pressing force) changes.

Such fluctuations in developing pressure will cause blurred printing if the driving force works in the direction of decreasing the developing pressure, and will cause fogging of developer adhering to the white background if the driving force works in the direction of increasing the developing pressure. occurs.

Therefore, in the prior art, even if the developing pressure can be made uniform in the axial direction, the overall developing pressure fluctuates, resulting in misaligned printing and fogging.

Therefore, an object of the present invention is to provide a one-component developing device that can prevent fluctuations in the overall developing pressure due to the driving of the developing roller.

[Means to solve the problem]

FIG. 1 is a diagram showing the principle of the present invention.

As shown in FIG. 1, the present invention comprises a developing unit 2 including a developing roller 7 for supplying monocomponent toner 4 to an image bearing member 1 on which an electrostatic latent image is formed; A drive for driving the developing roller 7 in a one-component developing device including a biasing means 10 for urging the developing roller 7 toward the image carrier 1 and pressing the developing roller 7 against the image carrier 1. A source 11 is provided in the developing unit 2.

[Effect]

The present invention deals with fluctuations in driving load torque of the developing device unit 2;
The pressing of the developing roller rough is made to be independent of pressure.

That is, the drive source 11 is provided in the developer unit 2, and the positional relationship between the drive source 11 and the developing roller 7, etc. of the developer unit 2 is fixed regardless of the movable operation of the developer unit 2.

Therefore, the moment caused by the drive of the drive source 11 is processed internally regardless of the entire developing device unit 2, so that even if there is a fluctuation in the driving load torque, the pressing pressure of the developing roller does not change.

Also 1. Since the positional relationship is fixed in this way and all axial moments are processed within the unit 2, the pressure on the left and right sides of the developing roller 7 in the axial direction is made uniform, and no special auxiliary means is required.

That is, when the drive load torque fluctuates, in the conventional technology, for example, when the drive force from the motor is transmitted through the gear train, the gear on the developing unit 2 side and the gear on the apparatus main body (motor) side may not mesh. The developing rollers are separated from each other and the distance between them varies, and since the motor serving as the driving source is fixed to the main body of the apparatus, the pressing force of the developing roller also varies. However, in the present invention, the driving source is inside the developing unit,
Even if the interval changes, it is absorbed by the urging means, and the pressing force of the developing roller does not change.

〔Example〕

(a) Description of the first embodiment FIG. 2 is a block diagram of a developing device according to an embodiment of the present invention.

In the figure, reference numeral 1 indicates the OPC photosensitive drum as the image bearing member, which has a diameter of 60 mm and a surface speed of 70 mm/
s, and after its surface is charged to 1650 V by a corona discharger (not shown), light irradiation is performed according to the information to be recorded by a laser scanning optical system, an LED exposure optical system, etc. (not shown). An electrostatic latent image is formed.

Reference numeral 2a denotes a one-component developing device, which has the following configuration in order to visualize an electrostatic latent image by supplying one-component non-magnetic toner onto the OPC photosensitive drum 1.

That is, the developer container 3 stores mono-component non-magnetic toner 4 having an average particle size of about 10 μm, and the agitator 5 rotates in the six directions of arrows within the developer container 3 to store the mono-component non-magnetic toner 4. The one-component non-magnetic toner 4 is charged to a negative polarity (-) by causing friction between the toner and the one-component non-magnetic toner.

The paddle roller 6 is a first roller formed at the bottom of the developer container 3.
By rotating in the direction of arrow B, one-component non-magnetic toner to 4 present at the lowest position in the developer container 3 is pumped up and supplied in the direction of a developing roller 7, which will be described later.

The aforementioned developing roller 7 rotates in the direction of arrow C, and conveys the one-component non-magnetic toner 4 conveyed by the paddle roller 6 to the contact portion with the OPC photosensitive drum 1 while adsorbing it to its surface, and transfers it to the contact portion with the OPC photosensitive drum 1. This is for visualizing the electrostatic latent image on the photosensitive drum 1.

The developing roller 7 has, for example, a diameter of 20 mm, a volume resistance value of IO4 to 1010 Ω·m (optimally 106 Ω-m),
Polymer foamed polyurethane (open-cell state) with a hardness of 10 to 35° (measured with an Asker-C hardness meter: optimally 10')
A developing bias voltage (-300 V) is applied through the central axis of the conductive layer 7b made of a single layer 7b and a rigid body (not shown).

Further, the developing roller 7 is pressed with a linear pressure of 22 to 50 g/cm (optimal 43 g/cm), and is pressed against the OPC photosensitive drum rotating in the direction of the arrow so that the nip has a width of 1 to 3.5 mm.

The layer thickness regulating bias blade 8 is made of aluminum or stainless steel, etc., and is rotatably provided around a shaft 8a, and applies a linear pressure of 26 g in the direction of arrow X to the developing roller rough by a biasing means such as a spring (not shown). /mm, the thickness of the toner layer on the developing roller 7 is regulated to a constant value, and a voltage of ~400V is applied.
In this embodiment, the one-component non-magnetic toner 4 is charged to a negative polarity by frictional charging, and a voltage is applied to prevent the charge from leaking.

The collection roller 9 has a volume resistivity lO similar to the developing roller 7.
It is made of high-molecular foam polyurethane with a hardness of approximately 10 to 70 degrees, and is disposed within the second recess 3b of the developer container 3.

This collection roller 9 has a diameter of 11 mm and a circumferential speed of 70 mm.
/s, the nip thickness is set to 1 mm, and further,
Recovery bias voltage (-300V to -
250 V) is applied to mechanically and electrically collect the one-component non-magnetic toner 4 from the surface of the developing roller rough, and eliminate mechanical and electrical history from the developing roller 7.

As will be described later, the drive all is provided in the developer 2a or the developer holding mechanism 2b of the developer unit 2, and is provided to rotate the agitator 5, paddle roller 6, recovery roller 9, and developer ports 7 to 7.

3 and 4 are configuration diagrams of the first embodiment of the present invention, FIG. 3(A) is a perspective view thereof, FIG. 3(8) is a top view thereof, and FIG. 4 is a sectional view thereof. It is.

In the figures, the same parts as those shown in FIGS. 1, 2, and 7 are indicated by the same symbols.

The developing device holding mechanism 2b includes a lock a that holds the developing device 2a.
A structure 20 is provided to center the developing device 2a and hold it together.

The holding mechanism 2b is provided with rollers 22 (FIG. 4) at its lower part, and is configured to easily move in the direction of pressing against the photosensitive drum 1 along a fixed guide rail 21.

The holding 81 structure 2b is applied with pressing force by the urging means 10 (FIG. 4), and is pressed against the photosensitive drum 1.
Develop the latent image on the photosensitive drum l.

At this time, the guide rail 21 is provided horizontally with respect to the moving direction, so that the weight of the developing device 2a and the holding mechanism 2b itself does not affect the pressing pressure.

This holding mechanism 2b is provided with a drive motor 11, and a gear G1 of the drive motor 11 rotates gears G2, G3, and G4 of each part of the developing device 2a, thereby rotationally driving each part.

In such a configuration, since the drive motor 2 is provided in the developer unit 2 (holding mechanism 2b), the moment applied to each drive gear due to the drive of the drive motor 11 is all processed within the developer holding mechanism 25. Therefore, the pressing pressure of the developing roller does not fluctuate.

Further, in this embodiment, since the developing device holding mechanism 2b is provided with the drive motor 11, even if the developing device 2a is replaced,
The drive motor 11 can be used as is.

(b) Description of the second embodiment FIG. 5 is a block diagram of a second embodiment of the present invention.

In the figures, the same parts as those shown in FIGS. 1, 2, 3, 4, and 7 are indicated by the same symbols.

In this embodiment, unlike the previous embodiment in which the drive motor 11 was provided in the holding mechanism 2b of the developer unit 2, the developing device i? A drive motor 11 is provided in S2a.

Even with this configuration, the same operations and effects as in the first embodiment can be achieved.

However, when replacing the developing device 2a, it is necessary to replace the entire drive motor 11, or to remove the motor 11 and reinstall it on another device.

(C) Description of the third embodiment FIG. 6 is a block diagram of a third embodiment of the present invention.

In the figures, the same parts as those shown in FIGS. 1 to 5 and 7 are indicated by the same symbols.

In this embodiment, the developing device holding mechanism 2b is of a swing type.

That is, a stand 23 is provided as the holding mechanism 2b, and the am 24 provided on the developing device 2a is engaged with the shaft of the stand 23, so that the developing device 2a is configured to be movable around the shaft of the stand 23. There is.

For this reason, the biasing means 10 directly biases the developing device 2a, and the drive motor 11 is provided in the developing device 2a.

Even in this case, the same operation and effect as in the first embodiment can be achieved.

(Mountain) Description of Other Embodiments In the above-mentioned embodiments, the developing device having the configuration shown in FIG.
The photoreceptor is not limited to a PC photoreceptor, but may be any other photoreceptor or dielectric material.

Although the present invention has been described above with reference to examples, the present invention can be modified in various ways according to the gist of the present invention, and these are not excluded from the present invention.

〔Effect of the invention〕

As explained above, according to the present invention, since the drive source for the developer is provided in the developer unit, fluctuations in the drive load torque of the developer do not affect the pressing pressure of the developing roller, resulting in blurred printing and This has the effect of preventing fogging, and contributes to improving the development characteristics of a one-component developing device in which the pressing pressure of the developing roller is a problem.

[Brief explanation of drawings]

Figure 1 is a diagram of the principle of the present invention, Figure 2 is a configuration diagram of an embodiment of the developing device of the present invention, Figures 3 and 4 are
The figure shows the configuration of the first embodiment of the present invention, Figure 5 shows the configuration of the second embodiment of the invention, Figure 6 shows the configuration of the third embodiment of the invention, and Figure 7 shows the configuration of the prior art. It is an explanatory diagram. In the figure, 1--image bearing member (photosensitive drum), 2--developing unit, 4--11-component toner 7---1 developing roller, 10-biasing means, 11--1 driving source.

Claims (1)

[Scope of Claims] A developing unit (2) comprising a developing roller (7) for supplying a monocomponent toner (4) to an image carrier (1) on which an electrostatic latent image is formed; and a biasing means (10) for biasing the developing roller (7) toward the image carrier (1) and pressing the developing roller (7) against the image carrier (1). A one-component developing device, characterized in that the developing unit (2) is provided with a drive source (11) for driving the developing roller (7).