JP2003255645A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus having a process unit maintaining a stable power feeding state without generating a chattering oscilla tion when bias voltage is fed to a rotating roll which is in pressure contact with a connecting terminal and rotating in the same direction. <P>SOLUTION: In the rotating roll, a power feeding shaft end is formed in a round-end shape having an arc section. The arc state round-end shaft end is brought into pressure contact with the connecting terminal by an elastic body having vibration absorbing function and the bias voltage is fed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image recording apparatus represented by a copying machine, a printer, and a facsimile apparatus, and more specifically, a conduction mechanism for bias power supply to the recording apparatus related to image formation. It is about.

[0002]

2. Description of the Related Art Conventionally, in an image recording apparatus such as a copying machine, a printer and a facsimile machine, a developing section, a transfer section including a photosensitive drum, and the like are integrated into a process unit to form a main body of the image recording apparatus. The process unit is detachably mounted to simplify the maintenance.

It is necessary to apply a predetermined voltage to these process units, and when installing them in the image recording apparatus main body, it is necessary to electrically connect them to the main body power supply section provided in the apparatus.

In particular, when supplying power to the developing roller, it is necessary to supply a bias voltage to the shaft ends of the central axes of a pair of rotating rollers that rotate in the same direction in a pressure contact state, and the plate is energized from the main body power supply unit. Electrical connection is achieved by contact between the connection terminal composed of a spring and the end of the central shaft of the developing roller. (See JP-A-10-301465)

[0005]

However, between the developing roller and the toner supply roller in the developing unit, in which the outer peripheral portion having elasticity is pressed and rotated in the same direction,
Since they rotate in contact with each other while being rubbed in a pressure contact state, the contact between the leaf spring-shaped abutting portion and the planar shaft end portion in the electric connection portion at the central shaft shaft end repeats strength and weakness, which may cause chatter vibration.

Further, when the contact between the flat spring-shaped contact portion, which is a surface contact or a line contact, and the flat shaft end portion is repeatedly strong and weak, the contact portion may become non-contact, resulting in poor conduction or an electric circuit. Is causing the malfunction of.

An object of the present invention is to provide an image having a process unit capable of maintaining a stable power supply state without causing chatter vibration at a contact portion of a connection terminal when power is supplied to a central axis end of a rotary roller. A recording device is provided.

[0008]

In order to achieve the above object, the invention according to claim 1 provides a process unit having a rotating roller with a bias voltage from a power source of an apparatus main body and an axis of a central axis of the rotating roller. Press the end and the connection terminal together,
An image recording apparatus configured to supply power is characterized in that the shaft end of the central shaft is formed in a rounded shape with an arcuate cross section.

According to the invention of claim 1 having the above-mentioned structure, the central axis end portion is formed in a rounded shape with an arcuate cross section, so that the bias is not a surface contact or a line contact but a point contact. A voltage can be supplied, the torque that vibrates the connection terminal is reduced, and chatter vibration can be suppressed.

The invention according to claim 2 is characterized in that the connection terminal is a leaf spring-like member having a flat contact portion.

According to the second aspect of the present invention having the above-mentioned structure, the contact between the flat contact portion and the rounded tip end portion of the arcuate section (spherical shape) results in point contact, and due to the elasticity of the leaf spring. Since the contact force is applied, the contact is ensured regardless of the shape and accuracy of the leaf spring, and stable power supply is possible.

According to a third aspect of the present invention, an elastic body having a vibration absorbing property is elastically disposed on the back side of the contact portion, and the shaft end of the central shaft and the leaf spring-like connection terminal are in pressure contact with each other. The feature is that

According to the third aspect of the present invention having the above structure, even if chatter vibration occurs due to rotation of the rotary roller, the connecting terminal is pressed against the end of the central shaft by the elastic body having a vibration absorbing performance. Since the configuration is adopted, chatter vibration can be absorbed and a stable contact state can be maintained.

According to a fourth aspect of the present invention, in the image recording apparatus configured to press the axial end of the central axis of the rotary roller and the connection terminal to supply the bias voltage, the axial end of the central axis is flat. And the connecting terminal is a leaf spring-like member, and an elastic body having vibration absorbing performance is disposed in a resilient state on the back side of the contact portion where the connecting terminal contacts the shaft end of the central shaft, and the central shaft The shaft end and the leaf spring-like connection terminal are brought into a pressure contact state.

According to the invention of claim 4 having the above-mentioned structure, even if the shaft end of the rotary roller is flat, the elastic body having a vibration absorbing property allows the connecting terminal of the leaf spring-like member to have a central axis. Since the end portions are pressed against each other, chatter vibration can be absorbed and a stable contact state can be maintained.

The invention according to claim 5 is characterized in that the rotating roller is a rotating roller which rotates in the same direction while being pressed against another rotating roller.

According to the invention of claim 5 having the above structure, even if a large frictional force is generated between the pair of rollers rotating in the same direction and chatter vibration occurs, the power feeding portion is in point contact. Moreover, since the contact force is applied by the elastic body having the vibration absorbing performance, chatter vibration can be absorbed and stable power supply can be performed.

The invention according to claim 6 is characterized in that the process unit is a developing unit, the rotating roller is a developing roller, and another rotating roller is a toner supply roller.

According to the sixth aspect of the present invention having the above-mentioned structure, a predetermined bias voltage can be stably applied to the developing unit in which the developing roller and the toner supply roller are in pressure contact with each other and rotated in the same direction. It is possible to obtain an image recording apparatus having a stable printing function in order to prevent chatter vibration.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an image recording apparatus according to the present invention will be described below with reference to FIGS.

FIG. 1 shows a bias voltage applying section at the end of the central shaft of a rotary roller according to the present invention, and FIG. 1A is a plan view showing the connection of a round shaft end having an arcuate section and a flat connecting terminal. And (b) is a plan view showing a connection in which a planar shaft end and an elastic body apply pressure contact force, and (c) shows a connection in which a cross-section arcuate tip round shaft end and an elastic body apply pressure contact force. FIG. FIG. 2 is a plan view showing an end portion of the developing roller having the bias voltage applying portion according to the present invention. Figure 3
FIG. 3 is an overall perspective view of a developing unit. FIG. 4 is a schematic explanatory view showing the layout of each unit of the image recording apparatus.
FIG. 5 is an overall sectional view showing the inside of the image recording apparatus.

As shown in FIGS. 4 and 5, the image recording apparatus A is provided with respective units such as a developing unit 10, a drum unit 20, a fixing unit 30, etc. In particular, the developing unit 10 and the drum unit 20 are integrated as a process unit. It is configured to be removable. Further, a paper storage unit 60 for storing the recording paper P is disposed below the main body of the image recording apparatus A. Above the recording device A is A
A DF (automatic document feeder) 40 is provided and has a fax function and a copy function. To record an image on the recording paper P, one sheet of the recording paper P is picked up by the separating and feeding means, conveyed toward the developing unit 10, the image is transferred by the drum unit 20, and fixed by the fixing unit 30, The recording paper P on which the image is recorded is sent to the paper discharge unit 50.

A developing unit 10, a drum unit 20, and a fixing unit 3 which are integrated as a unit.
0 is detachably attached to the apparatus main body for maintenance or parts replacement. Further, each of the units 10, 20, and 30 is configured such that the upper part of the image recording apparatus A is opened and the unit can be freely inserted and removed from the upper part for ease of operability.

The developing unit 10 includes the toner 12, the toner supply roller 6, the supply roller 6 and the drum unit 2.
The developing roller 1 is disposed between the photosensitive drum 21 and the photosensitive drum 21, and the toner regulating blade 11 is elastically contacted with the peripheral surface of the developing roller 1 on the downstream side in the conveying direction of the toner 12. ing.

The toner supply roller 6 is arranged so that the developing roller 1 and the roller portions are in pressure contact with each other, and rotates in the same direction as the developing roller 1 as shown by the arrow in the figure. Due to this rotational movement, the toner supply roller 6 functions to supply the toner 12 to the developing roller 1, frictionally charge the toner at the contact portion with the developing roller 1, and scrape unused toner on the developing roller 1. To do.

The drum unit 20 includes a photosensitive drum 21,
The transfer roller 22, the charging brush 23, and the memory removal brush 24 are provided to form a unit. A recording head (LED head) 25 is disposed around the photosensitive drum 21, and the recording head 25 causes the photosensitive drum 21 to move.
The image written on the photosensitive drum 21 is transferred onto the recording sheet P conveyed by the conveying roller 13 and recorded.

A fixing unit 30 for fixing the toner image transferred onto the recording paper P is disposed downstream of the drum unit 20. The fixing unit 30 includes a heat roller 31 and a pressure roller 32 that are in pressure contact with each other, a discharge roller 33 that discharges the fixed recording sheet P, and a separation unit that prevents the recording sheet P from winding around the heat roller 31. And a claw 34.

The recording paper P on which the image is transferred is heated and pressed by passing through the nip portion between the heat roller 31 and the pressure roller 32 to fix the image and form a permanent image. The recording paper P on which the image has been fixed is ejected by a paper ejection roller 33 to a paper ejection unit 50 outside the apparatus.

A bias voltage supplied to the developing unit 10 and a power supply method will be described with reference to FIGS. 1 to 3. As shown in FIG. 1A, the developing roller 1, which is a rotating roller supplied with a bias voltage, has conductive butadiene on the peripheral surface of the central shaft 1a made of a conductive metal material such as stainless steel. A roller formed by covering the NBR layer 1b made of acrylonitrile rubber or the like,
The surface of the NBR layer 1b is finished to be smooth. A bias voltage (for example, -300 V to -40) is applied to the developing roller 1 from a shaft end 2 which is a thin end of the central shaft 1a.
0V, preferably -350V) is applied. Further, the toner supply roller 6 is configured by covering the peripheral surface of the central shaft body formed of a conductive metal material such as stainless steel with a foam layer having conductivity, for example, a foam layer made of urethane foam. ing. A bias voltage (for example, -600V to -700V, preferably -6) is applied to the toner supply roller 6.
50V) is applied.

The axial distance between the toner supply roller 6 and the developing roller 1 is set to be slightly smaller than the total of the respective roller radii, so that the abutting portions of both rollers are in a pressure contact relationship. The frictional action between the toner supply roller 6 and the developing roller 1 due to this pressure contact relationship and rotation in the same direction and the bias voltage applied to each roller are combined to charge the toner 12 existing in the vicinity of both rollers 6, 1. And
The toner 12 filled in the bubbles of the foam layer is transferred to the developing roller 1 side by the rotation of the toner supplying roller 6, and at the pressure contact portion between the toner supplying roller 6 and the developing roller 1, due to the potential difference between the two rollers, the toner is Adhere to the surface of the developing roller 1. The toner attached to the surface of the developing roller 1 is conveyed to the photosensitive drum 21 side by the rotation of the developing roller 1. On the way, the layer thickness of the toner adhered to the surface of the developing roller 1 is made uniform by the toner regulating blade 11.

Next, a bias voltage feeding method will be described. FIG. 3 shows a developing unit 10, in which a spacer 7 is attached to the shaft end portion 2 of the developing roller 1 so that the distance between the developing roller 1 and the photosensitive drum 21 is constant and the contact force is uniform. Is configured to. A plurality of connection terminals 3 are provided on the lower portion of the side surface of the main body of the developing unit 10 so as to elastically contact the main body power source (not shown) of the image recording apparatus to supply electric power. A member is projected from the side wall to the outside. When the developing unit 10 is attached to the main body of the image recording apparatus, the connection portions 3A, 3B and 3C of the connection terminal 3 with the main body power source are elastically contacted with the main body side power source connection terminals (not shown) to supply a predetermined bias voltage. To be done.

The inside of the developing unit 10 of the connection terminal 3 will be described with reference to FIGS. The shaft end portion 2 of the developing roller 1 is in contact with the contact portion 3a of the connection terminal 3 and is in a conductive state. The shaft end 2 of the developing roller 1 is rotatably arranged via a bush 5, and a gear 8 mounted on the opposite shaft end meshes with a gear (not shown) mounted on the photosensitive drum 21. Is driven to rotate. The connection terminal 3 is made of a plate-shaped conductive metal member (for example, phosphor bronze), and both the connection portion 3A with the main body power source portion and the contact portion 3a which is the connection end with the developing roller have elasticity. The developing unit 10 is detachable from the main body of the image recording apparatus and ensures reliable and stable electrical connection.

In the power feeding portion shown in FIG. 1A, the contact portion 3a of the connection terminal 3 is flat, and the power feeding portion of the shaft end portion 2 of the developing roller 1 has a rounded tip end having an arcuate cross section. This is an example formed on the end 2a. Since the abutting portion 3a is a leaf-spring-shaped conductive metal plate material and is in pressure contact with the rounded shaft end 2a, which is the shaft end of the power feeding part, by point contact, chatter vibration is generated in the developing roller. Even if it occurs, a stable contact state can be maintained.

In the power feeding portion shown in FIG. 1B, the elastic body 4 is arranged so that the contact portion 3a of the connection terminal 3 is brought into pressure contact with the flat shaft end 2b which is the shaft end of the power feeding portion of the developing roller 1. It is another example. The elastic body 4 is an elastic rubber body having a vibration absorbing performance, and chloroprene rubber is used in this embodiment. Further, the hardness of Asker C55 is preferably around 55 degrees. The elastic body 4 is compressed to the length L1 at the time of mounting with respect to the initial length L0 of the elastic body 4, and is pressed by the elasticity of the elastic body 4 in addition to the elasticity of the contact portion 3a of the connection terminal 3. . Since the elastic body 4 is a rubber body having a high elasticity, even if a large frictional force is generated between the pair of rollers which rotate in contact with each other and chatter vibration is generated, the chatter vibration is not amplified and the vibration is efficiently absorbed. Can be attenuated.

In the power feeding portion shown in FIG. 1 (c), the connection terminal 3 to which the elastic body 4 having the vibration absorbing performance is attached and the tip end rounded shaft end 2a having the arc-shaped cross section in the power feeding portion are connected. Show.
In this example, chatter vibration is absorbed and attenuated, and power is supplied by point contact, so that more stable electrical connection can be obtained.

Although the power supply mechanism to the rotating body according to the present invention has been described with respect to the developing roller of the developing unit, the mechanism is effective not only for the developing unit but also for supplying power to the shaft ends of the central axes of other rollers. That is clear.

[0037]

According to the invention described in claim 1, when the bias voltage is supplied from the power source of the apparatus main body to the process unit having the rotating roller, the central axis end of the rotating roller and the connecting terminal are pressed. In the image recording apparatus configured to supply power by doing so, since the central axis end is formed in a rounded shape with an arcuate cross section, a bias voltage can be supplied by point contact and the connection terminal is vibrated. The torque can be reduced and vibration can be suppressed. In this way, stable bias power supply can be achieved simply by processing the shaft end of the power supply section into a rounded shape.

According to the second aspect of the present invention, since the connection terminal is the leaf spring-like member having the flat contact portion, the flat contact portion and the end portion of the rounded shaft having the arcuate cross section are provided. The contact is point contact, and the contact force is applied by the elasticity of the leaf spring. The contact is ensured regardless of the shape and accuracy of the leaf spring, and stable power supply is possible.

According to the third aspect of the invention, an elastic body having a vibration absorbing property is elastically disposed on the back side of the contact portion, and the central shaft end and the leaf spring-like connection terminal are in pressure contact. Therefore, even if chatter vibration occurs in the rotating roller due to rotation, the elastic body having a vibration absorbing property can absorb the chatter vibration and maintain a more stable electrical connection state.

According to the fourth aspect of the invention, the shaft end of the central shaft is made flat, and the elastic body having the vibration absorbing property is placed in the elastic state on the back side of the abutting portion of the connection terminal made of the leaf spring member. Since the flat central shaft end and the flat spring-like connecting terminal are in pressure contact with each other, even if the central end of the rotary roller is flat, the elastic body having the vibration absorbing performance can be used. It is possible to absorb chatter vibration and maintain a stable electrical connection state.

According to the fifth aspect of the invention, the rotating roller is a rotating roller that rotates in the same direction while being pressed against another rotating roller. Therefore, between the pair of rollers that rotate in the same direction, Even if a large frictional force is generated and chatter vibration is generated, the chatter vibration of the connection terminal portion, which is the power feeding portion, is absorbed and attenuated, so that stable power feeding can be performed.

According to the invention of claim 6, since the process unit is the developing unit, the rotating roller is the developing roller, and the other rotating roller is the toner supplying roller, the developing roller and the toner supplying roller are It is possible to obtain an image recording apparatus having a stable printing function by stably applying a predetermined bias voltage and preventing chatter vibration in a developing unit which is brought into a pressure contact state and rotated in the same direction.

[Brief description of drawings]

FIG. 1 is a plan view showing a bias voltage applying portion at a central axis end portion of a rotary roller according to the present invention, and FIG. (B) is a plan view showing a connection in which a flat shaft end portion and a resilient body apply a pressure contact force, and (c) shows a connection in which a rounded arcuate end portion of the rounded shaft end portion and a resilient body apply a pressure contact force. It is a top view.

FIG. 2 is a plan view showing an end portion of a developing roller having a bias voltage applying portion according to the present invention.

FIG. 3 is an overall perspective view showing a developing unit.

FIG. 4 is a schematic explanatory diagram showing a layout of each unit of the image recording apparatus.

FIG. 5 is an overall sectional view showing the inside of the image recording apparatus.

[Explanation of symbols]

1 Development roller (rotating roller) 2 Shaft end (center axis) 2a Tip rounded shaft end (power supply shaft end) 2b Flat shaft end (power supply shaft end) 3 connection terminals 3A, 3B, 3C connection part 3a contact part 4 elastic body 10 Development unit 20 drum unit 30 fixing unit A image recording device P recording paper

Claims (6)

[Claims] 1. An image recording apparatus configured to supply a bias voltage from a power supply unit of an apparatus main body to a process unit having a rotating roller by press-contacting a shaft terminal of a central axis of the rotating roller and a connection terminal. An image recording apparatus, wherein the central axis end is formed in a rounded shape having an arcuate cross section. 2. The image recording apparatus according to claim 1, wherein the connection terminal is a leaf spring member having a flat contact portion. 3. An elastic body having a vibration absorbing property is disposed on the back side of the abutting portion in an elastic pressure state so that the shaft end of the central shaft and the leaf spring-like connection terminal are in a pressure contact state. The image recording device according to claim 2. 4. An image recording apparatus configured to supply a bias voltage from a power source of an apparatus main body to a process unit having a rotating roller by press-contacting a shaft terminal of a central axis of the rotating roller and a connection terminal. , The shaft end of the central shaft is flat, the connection terminal is a leaf spring member, and an elastic body having vibration absorbing performance is elastically pressed against the back side of the contact portion where the connection terminal contacts the shaft end of the central shaft. The image recording apparatus is arranged in such a state that the shaft end of the central shaft and the leaf spring-like connection terminal are in pressure contact with each other. 5. The image recording apparatus according to claim 1, wherein the rotating roller is a rotating roller that rotates in the same direction while being pressed against another rotating roller. 6. The image recording apparatus according to claim 5, wherein the process unit is a developing unit, the rotating roller is a developing roller, and another rotating roller is a toner supply roller.