JP3515262B2 - Power supply structure to transfer roller - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called transfer belt power supply structure for supplying power to a transfer roller for supplying electric charges to the transfer belt.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus, there has been corona transfer in which a toner image formed on a photoconductor is transferred onto a sheet by using corona discharge by a transfer charger.
On the other hand, there is provided a transfer belt system in which transfer is performed without generating ozone by using a transfer belt whose surface is charged. In this transfer belt method, an endless transfer belt has a function of transporting a sheet by passing through a photoconductor drum, but since the transfer belt is charged, the sheet is electrostatically adsorbed and transported. Become. Therefore, there is an advantage that there is no problem that the paper being conveyed is wound around the photosensitive drum side.

The above-mentioned transfer belt is charged through a transfer roller arranged on the back side (inside the endless side) and is pressed against the photosensitive drum by the transfer roller.
FIG. 7 shows a conventional power feeding structure for a transfer roller.
Referring to the figure, a support shaft 91 of the transfer roller 90 is supported by a side plate 93 via a cylindrical bearing 92. The support shaft 91 penetrates the bearing 92, and an end surface 94 of the support shaft 91.
On the other hand, the electrode body 95 made of a leaf spring is elastically in contact. The electrode body 95 is fixed to the side plate 93 with screws 96. Reference numeral 97 is a transfer belt, and 98 is a power supply line connected to the electrode plate 95.

[0004]

In the above power feeding structure,
The electrode body 95 is composed of a leaf spring and is biased toward the support shaft 91 by its own elastic repulsive force. By the way, a leaf spring generally has a short stroke length. Therefore, there is a problem in that the contact of the electrode body 95 with the support shaft 91 is likely to be poor due to the influence of the shape precision and the mounting precision of the electrode body 95 itself.

In order to prevent the occurrence of such contact failure, it has been necessary to preliminarily increase the biasing force of the leaf springs forming the electrode body 95. However, when the biasing force is increased in this way, there is a problem in durability that the electric contact becomes unstable as a result of the leaf spring sagging. Further, when the urging force is increased, the rotational torque of the transfer roller becomes large, and the load on the drive system increases.

Therefore, an object of the present invention is to provide a power feeding structure to the transfer roller which does not require severe mounting accuracy, can secure stable electrical contact for a long period of time, and does not increase the rotational resistance of the transfer roller. Is to provide.

[0007]

To achieve the above object, according to an aspect of invention according to 請 Motomeko 1 feed in contact with the end face of the support shaft of the transfer roller for charging the transfer belt, to the transfer roller In the power supply structure, a holding cylinder that holds the electrode body connected to the power supply line so as to be movable in the axial direction of the support shaft, and a holding cylinder that holds the electrode body in the support cylinder. A compression coil spring for biasing the end face is provided , and one end of the compression coil spring is attached to the electrode body.
The electrode body, compression coil spring and power supply line are
The holding cylinder has a compression coil spring and an electric
An introduction opening for introducing the polar body into the holding cylinder is formed.
It is characterized by that.

In the above structure, the compression coil spring is used to urge the electrode body mounted in the holding cylinder through the introduction opening toward the support shaft. Since the stroke length of the compression coil spring is longer than that of the leaf spring, even if the set length slightly changes due to rough mounting accuracy, the contact failure of the electrode body does not occur. Therefore, in the compression coil spring, unlike the leaf spring, it is not necessary to increase the biasing force, and as a result, the settling does not occur and stable electrical contact can be secured for a long period of time. Further, since it is not necessary to increase the biasing force, the rotation torque of the transfer roller does not increase .

Moreover, first, the compression coil spring is housed in the holding cylinder through the introduction opening, and then the electrode body is housed in the holding cylinder through the introduction opening while bending the compression coil spring. Further, the electrode body and the compression coil spring can be removed from the holding cylinder in the reverse order. Since the electrode body and the compression coil spring are unitized, it is easy to handle, and there is no need for screwing work as in the past,
The operability of attaching and detaching the electrode body is very good. The invention according to 請 Motomeko 2, in the feed structure to the transfer roller according to claim 1,
The holding cylinder is formed with a stopper portion that engages with the electrode body in order to prevent the electrode body that is in contact with the support shaft from coming off the holding cylinder. It is characterized in that a cutout portion for leading out is formed.

With the above structure, the electrode body in the set state can be securely held in the holding cylinder without hindering the feeding of the power supply line to the outside of the holding cylinder. Invention according to claim 3
Of the support shaft of the transfer roller for charging the transfer belt.
A power supply structure for the transfer roller that contacts the end face and supplies power.
The electrode body connected to the power supply line.
Holding for holding the electrode body movably in the axial direction of the support shaft
The cylinder and the holding cylinder press the electrode body against the end face of the spindle.
And a compression coil spring for urging the supporting cylinder,
It is necessary to prevent the electrode body that has come into contact with the
A stopper part that engages with the electrode body is formed.
The par part has a notch that guides the power supply line to the outside of the holding cylinder.
It is characterized by being formed. The above configuration
Then, without hindering the derivation of the power supply line to the outside of the holding cylinder,
Make sure to hold the set electrode body in the holding cylinder.
You can

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 2 is a schematic side view showing a schematic configuration of an image forming unit of the image forming apparatus including a transfer belt power feeding structure according to an embodiment of the present invention. Referring to FIG. 1, in the image forming unit 1, a charging charger 3, a developing device 4, a transfer belt device 5 and a cleaning device 6 are arranged in this order around the photosensitive drum 2. In the image forming unit 1,
Photoreceptor drum 2 uniformly charged by the charger
After forming an electrostatic latent image by forming a document image on the peripheral surface of
The electrostatic latent image is visualized as a toner image by the developing device 4, the toner image is transferred to a sheet by the transfer belt device 5, and the residual toner is collected by the cleaning device 6.

The above-described transfer belt device 5 includes an endless transfer belt 10 slidably contacting the photosensitive drum 2, a driving roller 11 and a driven roller 12 wound around the transfer belt 10, and the transfer belt 10 as a photosensitive member. A transfer roller 13 sandwiched between the drum 2 and a pair of support rollers 14 and 15 which are disposed on both sides of the transfer roller 13 and movably support an upper track of the transfer belt 10, and a lower side of the transfer belt 10. And an auxiliary roller 16 that supports the track so that the track can travel freely.

The transfer belt 10 is made of, for example, polyurethane as a base material. In the transfer belt device 5, each of the rollers 11 to 16 is rotatably supported by a pair of side plates 17 (only one side plate 17 is shown in FIGS. 1 and 3) facing each other. The upper edge of each side plate 17 has a predetermined length in the traveling direction of the transfer belt 10,
A rib 37 having an L-shaped cross section (only one formed on one side plate 17 is shown) is integrally formed. This rib 3
Reference numeral 7 is for restricting the movement of the transfer belt 10 in the width direction to prevent the transfer belt 10 from meandering.

Conventionally, as shown in FIG. 8, a meandering prevention roller 121 pivotally supported by a support member 122 having a U-shaped cross section.
Was mounted so as to be pressed against the peripheral edge of the transfer belt 10 (see Japanese Utility Model Application Laid-Open No. 57-72037), the portions of the meandering prevention roller 121 and the support member 122 largely project upward and become an obstacle. However, there is also a problem that the manufacturing cost is increased due to the increase of the component cost and the assembly cost. On the other hand, in the present embodiment, since the ribs 37 are integrally provided on the side plate 17, the protruding height can be made extremely low (the upper surface of the rib 36 and the upper surface of the side plate 17 are flush with each other, and the ribs 36 are It is also possible not to project from 17 at all), and the manufacturing cost can be significantly reduced. Since the transfer belt 10 is made of a polyurethane base material or the like and is highly flexible, the transfer belt 10 can be easily attached to and detached from the rib 36 without being broken or scratched. it can.

As shown in FIGS. 1 and 3, the transfer roller 13 includes a support shaft 13a having a reduced diameter portion 13c, and an elastic layer 13b made of silicon rubber or the like and supported around the support shaft 13a. Consists of. In FIG. 1, the transfer roller 13
Is shown, and the support shaft 13a is the bearing 3
It is supported by the side plate 17 via 6. Further, referring to FIG. 3, the support rollers 14 and 15 are the same as the ground plate 31.
And grounded through the bearings 30 and each ground plate 3
1 are connected to each other via the extending piece 31f and are collectively connected to the ground wire 34.

Referring to FIGS. 1 and 5, the side plate 17 is integrally formed with a holding cylinder 18 for accommodating and holding an electrode body 19. With reference to FIG. 1, the electrode body 19 is pressed against the end surface 13d of the reduced diameter portion 13 at the end of the support shaft 13a. With reference to FIG. 1, the electrode body 19 is a bottomed cylindrical body made of copper, and the screw hole 19 a of the electrode body 19 has a terminal winding 21 as a terminal end of the power supply line 20 and one end of the compression coil spring 22. A screw 24 for fixing is screwed in and fixed through the portion 23. Thereby, as shown in FIG. 4, the electrode body 19, the compression coil spring 22, and the power supply line 20 form an integral unit.

1 and 5, the end surface portion 18a of the holding cylinder 18 is closed, and the electrode body 19 and the compression coil spring 22 are held on a part of the peripheral surface of the holding cylinder 18. An introduction opening 26 that can be introduced into the cylinder 18 is formed. In addition, the electrode body 19 accommodated in the holding cylinder 18 and abutted on the support shaft 13a is partially provided on the peripheral surface of the holding cylinder 28.
However, a pair of stopper portions 27 for preventing the holder cylinder 18 from falling off are formed adjacent to the lead-out opening 26. At the center of the stopper portion 27, the holding cylinder 1
Notch portion 2 for allowing the power supply line 20 connected to the electrode body 19 held in 8 to escape from the holding cylinder 18
8 are provided. Reference numeral 29 is a connector connected to the power supply line 20.

Next, the procedure for setting the electrode body 19 will be described with reference to FIGS. First, as shown in FIG. 6A, the other end portion 25 of the compression coil spring 22 is inserted into the holding cylinder 18 through the introduction opening 26, and then, as shown in FIG. After bending the spring 22 and inserting the electrode body 19 into the holding cylinder 18 through the introduction opening 26, the compression coil spring 22 is allowed to expand. As a result, as shown in FIG. 1, the compression coil spring 22 causes the electrode body 19 to move toward the end surface 1 of the support shaft 13a.
It is pressed and urged by 3d to secure electrical contact. In addition,
With the electrode body 19 thus set, the electrode body 1
The stopper portion 27 prevents 9 from falling out of the holding cylinder 18. In addition, as shown in FIG. 1, the power supply line 20 connected to the electrode body 19 is led out of the holding cylinder 18 through a notch portion 28 formed in the stopper portion 27.

According to the embodiment having the above structure, since the compression coil spring 22 having a longer stroke length than that of the leaf spring is used, even if the set length varies a little, contact failure of the electrode body 19 is caused. There is no. Therefore, in the compression coil spring 22, it is not necessary to increase the biasing force as in the conventional leaf spring, and as a result, no settling or the like occurs, so that stable electrical contact can be secured for a long period of time. Further, unlike the conventional leaf spring, it is not necessary to increase the biasing force, so that the torque of the transfer roller 13 is not increased and the torque cross can be suppressed.

The electrode body 19 and the compression coil spring 22 are also provided.
Is attached to and detached from the holding cylinder 18 through the introduction opening 26, and it is not necessary to perform screwing work as in the case of the conventional leaf spring, so that the electrode body 19 is very easily attached and detached. Further, since the stopper portion 27 that prevents the electrode body 19 from falling off is provided with the cutout portion 28 for leading out the power supply line 20, the electrode body in the set state is not hindered from preventing the power supply line 20 from being led out of the holding cylinder 18. 19 can be securely held in the holding cylinder 18.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

[0022]

In the invention according to claim 1, since the compression coil spring having a longer stroke length than that of the leaf spring is used,
Even if the set length fluctuates to some extent, the electrode body will not cause poor contact. Therefore, the compression coil spring does not require severe mounting accuracy and does not need to have a strong biasing force unlike a leaf spring, and as a result, does not suffer from settling or the like, so that stable electrical contact can be secured for a long period of time.
Further, since it is not necessary to increase the biasing force, the rotation torque of the transfer roller does not increase.

Moreover, the electrode body and the compression coil spring are attached to and detached from the holding cylinder through the introduction opening, and there is no need to perform screwing work as in the case of the conventional leaf spring. Operability is very good. Claim 2,
According to the third aspect of the invention, the electrode body in the set state can be securely held in the holding cylinder without hindering the feeding of the power supply line to the outside of the holding cylinder.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a power supply structure for a transfer roller according to an embodiment of the present invention.

FIG. 2 is a schematic side view showing a schematic configuration of an image forming unit including a transfer belt device to which the power feeding structure is applied.

FIG. 3 is a partially cutaway perspective view of a transfer belt device.

FIG. 4 is a perspective view of a unit including an electrode body, a compression coil spring, and a power supply line.

FIG. 5 is a perspective view of a holding cylinder for housing an electrode body and a compression coil spring.

6A and 6B are schematic views sequentially showing a process of mounting the electrode body and the compression coil spring on the holding cylinder.

FIG. 7 is a partial cross-sectional plan view showing a conventional power feeding structure to a transfer roller.

FIG. 8 is a schematic perspective view showing a structure for preventing meandering of a conventional transfer belt.

[Explanation of symbols]

10 Transfer belt 13 Transfer roller 13a spindle 13d end face 18 Holding tube 19 electrode body 20 power lines 22 Compression coil spring 23 End winding (one end) 26 Introductory opening 27 Stopper 28 Notch

Front page continuation (72) Inventor Ryuji Wataki 1-2-2 Tamatsukuri, Chuo-ku, Osaka City, Osaka Prefecture Mita Industry Co., Ltd. (72) In-house Rio Uchida 1-2-2 Tamatsukuri, Chuo-ku, Osaka City, Osaka Prefecture Within Mita Kogyo Co., Ltd. (56) Reference Japanese Unexamined Patent Publication No. 1-250966 (JP, A) Actual development No. 1-250966 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 13 / 02 G03G 13/14-13/16 G03G 15/00 G03G 15/02 G03G 15/14-15/16 H01R 13/02

Claims (3)

(57) [Claims] 1. A power supply structure for supplying power to a transfer roller by contacting an end surface of a support shaft of a transfer roller for charging a transfer belt, wherein the electrode body connected to a power supply line is housed in the electrode body. A holding cylinder for holding the body movably in the axial direction of the support shaft, and a compression coil spring for biasing the electrode body against the end face of the support shaft in the holding cylinder, the electrode body being provided with a compression coil. One end of the spring is attached
The electrode body, compression coil spring, and power supply line as a unit.
The holding cylinder has a compression coil spring and an electrode body.
Has an opening for introducing the
Feed structure to the transfer roller, characterized in that that. 2. The transfer roller power feeding structure according to claim 1, wherein the holding cylinder holds an electrode body which is in contact with the support shaft.
Strokes that engage the electrode body to prevent it from coming off the cylinder.
A stopper is formed and the stopper holds the power supply line.
A power feeding structure to a transfer roller, characterized in that a cutout portion for leading out to the outside of the cylinder is formed . 3. A transfer roller for charging a transfer belt.
Feeding power to the transfer roller by contacting the end face of the spindle
In the structure, when the electrode body connected to the power supply line is accommodated,
A holding cylinder that holds the body movably in the axial direction of the support shaft, and presses and urges the electrode body to the end surface of the support shaft in the holding cylinder.
E Bei a compression coil spring, the said holding cylinder, a stopper portion electrode body in contact with the support shaft is engaged with the electrode body so as to prevent disengagement from the holding cylinder is formed on the stopper portion, It is characterized in that a cutout portion for leading out the power supply line to the outside of the holding cylinder is formed.
Power supply structure to the transfer roller .