JP2532920B2 - Bias application mechanism of developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a bias applying mechanism of a developing device, and is used in, for example, an electrostatic transfer copying machine, a laser printer, and the like.

<Prior Art> Generally, as shown in FIG. 7, a developing device of an electrostatic transfer type copying machine has a developing device main body 1 made of a synthetic resin containing toner.
A developing roller 2 is built in the developing roller 2, and the developing roller 2 is a magnet body 4 fixed to the developing device main body 1 by a fixed shaft 3.
And a sleeve 5 rotating on the outer peripheral surface of the magnet body 4.
It is composed of The rotational force of the sleeve 5 is
Is transmitted integrally to the drive shaft 6 coaxial with the fixed shaft 3. Reference numeral 7 in the drawing denotes a coupling fixed to the drive shaft 6 for transmitting the rotational drive force from the main body of the copying machine to the drive shaft 6.

Further, in the bias applying mechanism of the developing device, the lead wire 8 for applying bias is connected to the fixed shaft 3,
Is applied to the sleeve 5 via the bearing 9 or 10.

<Problems to be Solved by the Invention> In the conventional bias applying mechanism, the connection of the bias to the main body of the copying machine is normally made by the connector located on the same side as the coupling of the drive connection of the developing device main body 1. However, it is necessary to route the lead wire from this connector to the fixed shaft 3 on the opposite side of the apparatus main body 1, which complicates the lead wire processing.

Further, it is desired to reduce the size of the entire developing device by arranging the lead wire 8 only on the drive shaft 6 side, and further, stable conductivity, durability and cost reduction are also desired.

In view of the above, it is an object of the present invention to provide a bias applying mechanism that can achieve downsizing of a developing device, stable conductivity, durability, and cost reduction.

<Means for Solving the Problems> In the means for solving the problems according to the present invention, as shown in FIGS. 1 and 2, the developing roller 2 is built in the developing device main body 1, and the conductive drive shaft 6 of the developing roller 2 is provided. In a developing device in which is rotatably supported on the outer surface 1a of the developing device main body 1, a fixing plate 13 for bias application, which penetrates the drive shaft 6, is fixed to the outside of the developing device main body 1, and the fixing plate A conductive rotary slide plate 14 facing and in contact with 13 is fixed to the drive shaft 6, and the slide plate 14 is a disc softer than the fixed plate 13 and cut along the circumferential direction. A contact body (cut-and-raised piece 31) that is raised and slidably contacts the smooth surface of the fixed plate 13 is formed.

Further, as another means for solving the problem, as shown in FIG. 4, the developing device main body 1 is internally provided with the developing roller 2, and the conductive drive shaft 6 of the developing roller 2 is rotated to the outer surface 1a of the developing device main body 1. In a freely supported bearing developing device, the developing device body 1
A fixed plate 13 for bias application, which penetrates the drive shaft 6, is fixed to the outside of the drive shaft, and a conductive disk-shaped rotary sliding plate 14 that faces and contacts the fixed plate 13 is fixed to the drive shaft 6. The sliding plate 14 has a plurality of contact bodies (cut-and-raised pieces 31) that are cut and raised along the circumferential direction thereof and are in sliding contact with the smooth surface of the fixed plate 13 at different radial positions. A plurality of contacts 32a to 32d are formed on the contact body, the tips of which are divided in the circumferential direction to come into contact with the fixed plate 13, and if the distances from the contacts 32a to 32d to the center of the drive shaft 6 are different from each other. It has been squeezed.

<Operation> In the above means for solving the problem, the sliding plate 14 is in pressure contact with the fixed plate 13, and when the drive shaft 6 is rotated, the contact body of the sliding plate 14 slides on the smooth surface of the fixed plate 13. At the same time, the sleeve 5 of the developing roller 2 rotates.

In addition, the bias from the body side is fixed plate 13, sliding plate 1
4, applied to the sleeve 5 via the drive shaft 6.

By providing the sliding plate 14 on the drive shaft 6 of the developing roller 2 as described above, it is not necessary to apply a bias to the fixed shaft 3 far from the drive source as in the conventional example of FIG. Since the bias can be applied from the side and the fixing plate 13 can be connected to the power connector 19 on the same side as the drive source via the lead wire 24, the lead wire processing is also simplified.

In addition, the sliding plate 14 is a soft material rich in elasticity,
Since the contact body cut and raised along the circumferential direction comes into pressure contact with the smooth surface of the fixed plate 13, the contact body absorbs the vibration regardless of the vibration of the sliding plate 14 and the pressure change is reduced. Stable conductivity is obtained without damaging the smooth surface.

In another problem solving means, the contact 32a of the sliding plate 14 is
32d and the fixed plate 13 are in contact with each other, their positions are different in the radial direction and the distance from the center of the drive shaft 6 is also different. Therefore, even if the sliding plate 14 vibrates, the sliding plate 14 and the fixed plate 13 are constantly in contact with each other somewhere, and the stability of conduction can be obtained. Also, the fixed plate
There is no concentrated contact with one surface of the surface of 13, the surface is less scratched and scratched, and durability is improved.

<Example> Hereinafter, an example of the present invention is described based on a drawing. FIG. 1 is an exploded perspective view of a bias applying mechanism portion showing a first embodiment of the present invention, FIG. 2 is a front view of a sliding plate, and FIG. 3 is a side view of the sliding plate. The same functional components as those of the conventional component shown in FIG. 7 are designated by the same reference numerals.

As shown in the figure, in the bias applying mechanism, in the developing device in which the conductive drive shaft 6 of the developing roller 2 is rotatably supported by the developing device body 1, the drive shaft 6 penetrates the outer surface of the developing device body 1. And a fixed plate 13 for bias application mounted so as to face the fixed plate 13 so as to make contact with the drive shaft 6.
And a conductive rotary sliding plate (14) that is crimped and fixed to.

The developing device main body 1 and the developing roller 2 have the seventh construction.
It is similar to the prior art shown in the figure.

The drive shaft 6 is rotatably projected through a bearing 16 to a boss 15 projecting on the outer surface 1a of the developing device main body 1 and transmits a rotational driving force from a copying machine main body (not shown) to its tip. The coupling 7 is fixed.

The fixed plate 13 is a thin disk-shaped one in which a bearing fitting hole 17 is formed in the center slightly larger than the outer diameter of the bearing 16, and a lead wire connecting piece 18 is projected from one end thereof. ing.

A power supply connector 19 for applying a bias is fixed to the bosses 20 and 21 on the outer surface of the developing device main body 1 by screws 22 adjacent to the connection piece 18. Then, the round terminal 25 of the lead wire 24 from the power supply connector 19 and the screwing hole 26 of the connecting piece 18 are fitted to the boss 27 on the outer surface of the developing device main body 1 and fixed by the screw 28.

The sliding plate 14 is formed in a thin disk shape, and a center hole 30 for fitting the drive shaft 6 is formed at the center thereof. Also,
The sliding plate 14 is formed with a pair of arcuate cut-and-raised pieces 31 around the center hole 30. The cut-and-raised pieces 31 have elasticity, and the tip of the cut-and-raised piece 31 is attached to the plate surface of the fixed plate 13. A contactor 32 that contacts is formed. The sliding plate 14 is arranged closer to the coupling 7 of the drive shaft 6 than the fixed plate 13 so that the contact 32 comes into pressure contact with the plate surface of the fixed plate 13.

In addition, a pair of protrusions 33 project in the center hole 30 of the sliding plate 14 in the center direction. On the other hand, the drive shaft 6 is formed with a pair of V-shaped grooves 34 in the axial direction for fitting and press-contacting the protrusions 33.

The fixed plate 13 and the sliding plate 14 are structured to stabilize the contact state. That is, the fixing plate 13 has a plate thickness of 0.5 mm in order to improve the flatness, and a hard material such as a stainless steel plate is used in order to improve the surface smoothness.

On the other hand, the sliding plate 14 is rich in elasticity (plate thickness 0.3 mm) so that the pressure change in pressure contact with the fixed plate 13 is small, and is made of a material softer than the fixed plate 13 so as not to damage the fixed plate 13 by contact sliding. For example, a phosphor bronze plate is used.

In the above structure, the fixed plate 13 and the sliding plate 14 are assembled as follows. That is, the fitting hole 17 of the fixed plate 13 is the bearing
Since it is slightly larger than the outer diameter of 16, the bearing 16 of the drive shaft 6 is fitted into the fitting hole 17 of the fixed plate 13, and the back surface of the fixed plate 13 is set to a position where it comes into contact with the boss surface of the developing device main body 1. Then, the screwing hole 26 of the fixing plate 13 is aligned with the boss of the developing device main body 1 and is screwed simultaneously with the terminal 25 of the bias lead wire 24.
Tighten with 28.

Next, the pair of protrusions 30 of the center hole 30 of the sliding plate 14 are fitted into the pair of grooves 34 of the drive shaft 6 of the sleeve 5, and the sliding plate 14 is press-fitted. Then, the coupling ring 7 for drive connection is similarly attached by press fitting or the like.

Further, the power supply connector 19 for bias is attached to the bosses 20 and 21 of the developing device main body 1 with screws 22.

Assembled as described above, the contactor 32 of the sliding plate 14 is pressed against the fixed plate 13. When the developing device is mounted on the main body of the copying machine, the coupling 7 is connected and the coupling 7 rotates, whereby the sliding plate 14, the drive shaft 6 and the sleeve 5 integrated with the sliding plate 14 rotate.

Further, the power supply connector 19 is connected to the bias power supply on the main body side, passes from the power supply connector 19 through the lead wire 24, and is fixed to the fixing plate 1.
A bias is applied to the sleeve 5 through the sliding plate 14 and the drive shaft 3.

In this way, by providing the sliding plate 14 on the drive shaft 6 of the developing roller 2, it becomes possible to apply a bias to the fixed shaft 3 without applying a bias as in the conventional example shown in FIG.
Since the lead wire 24 is connected to the fixed plate 13 on the same side as the power supply connector 19, the lead wire processing is also simplified.

Since the fixed plate 13 and the sliding plate 14 are made to face each other and are brought into contact with each other over as wide an area as possible, stable conductivity and durability can be obtained. In addition, sliding plate 14
If the area can be increased, the more contacts 32, the more stable conductivity can be obtained.

Further, since the fixed plate 13 and the sliding plate 14 are opposed to each other and are arranged on the drive shaft 6, the space for the bias applying mechanism may be minimized, and the space in the longitudinal direction of the developing roller 2 may be reduced. The dimensions can be made very small. Also, the number of parts is small, and the cost can be reduced.

Further, as in the above embodiment, the fixed plate 13 is made thicker than the sliding plate 14, and the material of the fixed plate 13 is harder, while the sliding plate 14 is elastic. If a soft material is used, the pressure contact force of the sliding plate 14 during rotation and sliding is stabilized, and the contact surface of the fixed plate 13 is not scratched or scratched, so that stable conduction and durability are improved.

Next, a second embodiment of the present invention will be described. FIG. 4 is a front view of a sliding plate showing a second embodiment of the present invention, and FIG. 5 is a side view of the sliding plate.

As shown in the figure, in this embodiment, a slit 35 is provided on the cut-and-raised piece 31 of the sliding plate 14 to increase the contact portion with the fixed plate 13, and the radius r1 to r4 from the center of each contact portion is changed and fixed. The sliding plate should be in contact with different parts of the plate 13, and the contact pressure should be necessarily different due to the different radii.
It is intended to improve the stability and durability of contact electric conduction by the rotation of 14.

That is, the slit 35 is formed at the tip of the cut-and-raised piece 31 of the first embodiment, the contactors 32a to 32d are formed on both sides thereof, and the radius from the rotation center of the contact portion of each contactor 32a to 32d.
Make r1 to r4 different (r1 <r2 <r3 <r4). Other configurations are the same as those of the first embodiment.

In the above configuration, the contact portions between the contacts 32a to 32d and the fixed plate 13 are increased and the pressure contact force of each contact portion is changed, so that the contact stability is good.

In addition, since the position of each contact portion in contact with the fixed plate 13 is changed, the surface of the fixed plate is not scratched or damaged, and the durability can be improved. Other functions and effects are similar to those of the first embodiment.

The present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

For example, the fixed plate 13 does not have to be fitted to the drive shaft 6, and may have a certain contact area with the sliding plate 14.
The sliding plate 14 is not limited to the cut-and-raised type as in the above embodiment, but may be a disc spring type as shown in FIG. 6 (a). In this case, the contact area between the sliding plate 14 and the fixed plate 13 can be increased.

Further, the fixing plate 13 may be arranged not on the developing device main body 1 side but on the copying machine main body side. In this case, the fixed plate
Although 13 must have a structure for escaping the coupling 7 of the drive shaft 6, if the coupling 7 has a shape as shown in FIG. 6 (b), a bias can be easily applied even when the developing device is fitted to the main body of the copying machine. it can.

Further, the fixing plate 13 and the power supply connector 19 are connected to the developing device main body 1
If it is arranged on the side, it is good to obtain a bias applied voltage specific to the developing device. That is, it is possible to attach a variable resistance or a specific resistance to the power supply connector 19 and set the resistance value according to the developing device.

<Effects of the Invention> As is apparent from the above description, according to the present invention, the fixing plate for bias application having the drive shaft penetrating therethrough is fixed to the outside of the developing device main body, and the conductive plate facing the fixing plate is in contact with the fixing plate. Since the rotary sliding plate of is fixed to the drive shaft, it is not necessary to apply a bias to the fixed shaft far from the drive source as in the conventional example of FIG. 7, and the bias can be applied from the side closer to the drive source. The fixing plate can be connected to the power supply connector on the same side as the drive source via the lead wire, and the lead wire can be shortened and the lead wire can be easily processed.

Moreover, since the fixed plate and the sliding plate are arranged outside the main body of the developing device, it will never happen that the developer is caught in the contact surface of each other and contact failure occurs, and it is easy to attach and detach for replacement. Can be done. In addition, use a hard material for the fixing plate, while using a soft, rich elastic material for the sliding plate to cut and raise the contact body that makes sliding contact with the smooth surface of the fixing plate along the circumferential direction. Since the pressure contact force of the sliding plate during rotation and sliding is stable, the contact body follows the contact body even if vibration occurs and a reliable contact state is obtained. Scraping and scratches are reduced, and conduction can be stabilized and durability can be improved.

Further, the sliding plate is provided with a plurality of contact bodies that are cut and raised along the circumferential direction thereof and are in sliding contact with the smooth surface of the fixed plate at different radial positions. Since a plurality of contacts that are divided into contact with the fixed plate are formed and the distance from each contact to the center of the drive shaft is different, the contact part between the sliding plate and the fixed plate during rotation. It is possible to increase the contact area and increase the contact area. Moreover, even if one contact body rolls laterally due to vibration or the like, the other contact body comes into contact with the fixed plate, so that the stability of conduction can be obtained and the fixed plate can be obtained. It is possible to prevent scratches and scratches on the surface of the steel sheet from concentrating on a part of the surface and further improve the durability.

In this way, by arranging the fixed plate and the sliding plate so as to face each other and slidably contact with each other, the rotation of the drive shaft is not hindered,
The space as a bias applying mechanism may be minimal, and the longitudinal dimension of the developing roller can be made extremely small,
In addition, when the number of parts is small and the cost can be reduced, an excellent effect can be obtained.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a bias applying mechanism portion showing a first embodiment of the present invention, FIG. 2 is a front view of a sliding plate, FIG. 3 is a side view of the sliding plate, and FIG. 5 is a front view of a sliding plate showing a second embodiment of the invention, FIG. 5 is a side view of the sliding plate, and FIG. 6 (a) is a side sectional view of a bias applying mechanism showing a third embodiment of the present invention. FIG. 6 (b) is a perspective view of the bias applying mechanism showing the fourth embodiment of the present invention, and FIG. 7 is a sectional view of a developing device using the conventional bias applying mechanism. 1: developing device main body, 2: developing roller, 6: drive shaft, 13: fixed plate, 14: rotary sliding plate, 19: power supply connector, 31: cut and raised piece, 3
2,32a to 32d: contacts.

Claims (2)

(57) [Claims] 1. A developing device in which a developing roller is built in the developing device main body, and a conductive drive shaft of the developing roller is rotatably supported by an outer surface of the developing device main body. A bias applying fixed plate penetrating the drive shaft is fixed, and a conductive rotary sliding plate facing and contacting the fixed plate is fixed to the drive shaft, and the sliding plate is
A bias applying mechanism for a developing device, wherein a circular plate that is softer than the fixed plate is formed, and a contact body that is cut and raised along a circumferential direction of the fixed plate to make a sliding contact with the smooth surface of the fixed plate is formed. 2. A developing device in which a developing roller is internally provided in a developing device main body, and a conductive drive shaft of the developing roller is rotatably supported by an outer surface of the developing device main body. A fixed plate for bias application penetrating the drive shaft is fixed, and an electrically conductive disc-shaped rotary sliding plate facing and in contact with the fixed plate is fixed to the drive shaft. A plurality of contact bodies that are cut and raised along the circumferential direction and are in sliding contact with the smooth surface of the fixing plate are formed at different positions in the radial direction, and the tips are divided along the circumferential direction to the fixing plate. A bias applying mechanism of a developing device, wherein a plurality of contactors that come into contact with is formed, and the distances from the contactors to the center of the drive shaft are made different.