KR101299448B1 - Electro-photographic image forming apparatus - Google Patents

Abstract

An electrophotographic image forming apparatus comprising: a rotating roller having a rotating shaft made of a conductive material; A high voltage generator; A frame supporting the rotating roller; An elastic material made of a conductive material interposed between the frame and the rotating roller to elastically press the rotating roller in a predetermined direction, and being connected to the rotating shaft of the rotating roller to receive the high voltage of the high voltage generator and transmit the received high voltage to the rotating shaft. And a member. As a result, the structure of the connecting device connecting the high voltage generator and the rotating roller can be simplified, and the productivity and assembly can be improved.

High voltage generator, HVPS, charging device, high voltage, connection, roller

Description

Electrophotographic image forming apparatus {ELECTRO-PHOTOGRAPHIC IMAGE FORMING APPARATUS}

1 is a perspective view of a high voltage connection device of a conventional image forming apparatus;

2 is a schematic view showing a connection relationship between a rotating roller and a high voltage generator of the image forming apparatus according to the present invention;

3 is a perspective view of a high voltage connection device of the image forming apparatus according to the present invention;

4a and 4b are assembled views of the high voltage connector of FIG.

5 is a cross-sectional view of a high voltage connection device installed at one end of the rotating roller of the image forming apparatus of FIG.

6 is a cross-sectional view of the other end of the rotary roller of FIG.

Explanation of symbols on the main parts of the drawings

100: image forming apparatus 103: frame

105: photosensitive drum 110: rotary roller

111: charging roller 113: developing roller

115: transfer roller 117: cleaning roller

120: high voltage generator 130: high voltage connection device

131: first elastic member 131a: circumferential contact

131b: elastic pressing portion 131c: connection extension portion

133: bushing 133a: insertion cylindrical portion

133b: bearing part 135: holder

135a: bushing accommodation portion 135b: protrusion

135c: circumferential contact portion crimping portion 135d: circumferential contact portion accommodating portion

141: second elastic member

The present invention relates to an electrophotographic image forming apparatus, and more particularly, to an electrophotographic image forming apparatus having improved connection structure between a rotating roller and a high voltage power supply.

BACKGROUND ART An electrophotographic image forming apparatus is an apparatus for forming an image on a print medium through charging, exposure, development, transfer, and fixing steps, and includes a scanner, a laser printer, and a multifunction printer. In the charging step, the charging roller contacts and charges the photosensitive drum surface to a predetermined potential. In the developing step, the negatively charged developer on the surface of the developing roller moves to an electrostatic latent image on the surface of the photosensitive drum in a relatively high potential state, thereby forming a visible image on the surface of the photosensitive drum. In the transfer step, the visible image of the surface of the photosensitive drum formed with such a developer is transferred to the print medium side by a transfer roller charged at a positive potential of several hundred volts. Finally, in the fixing step, the developer is fixed to the print medium by heat and pressure to form a complete image.

Therefore, the electrophotographic image forming apparatus electrically connects the high voltage generator (HVPS) and the rotary roller to the photosensitive drum side to charge the rotary rollers such as the charging roller, the developing roller, and the transfer roller to a predetermined potential. It is provided with a connecting device for elastically pressing.

The high voltage connection device of the conventional image forming apparatus, as shown in FIG. 1, has a coil spring 12, a bushing 13, and a holder 14. The holder 14 has a receiving groove 14a in which one end 13b of the bushing 13 is accommodated, and has a protrusion 14b protruding in the horizontal direction of the length of the rotary roller 11 at the lower side. At one end 13b of the bushing 13 is formed a bearing hole 13a for receiving and supporting the end of the rotating shaft 11a of the rotary roller 11, and the other end 13c is a protrusion 14b of the holder 14. Is inserted into The coil spring 12 is inserted into the protrusion 14b of the holder 14 and connected to the other end 13c of the bushing to transfer the electric potential generated from the high voltage generator to the bushing 13. In addition, the coil spring 12 elastically presses the holder 14 in the protruding direction of the protrusion 14b. As a result, the predetermined potential generated by the high voltage generator (not shown) is transferred to the rotating shaft 11a of the rotating roller 11, so that the surface of the rotating roller 11 is charged to the predetermined potential. The rotary roller 11 is also elastically pressed in the direction K of the protrusion 14b by the coil spring 12 which elastically presses the holder 14.

However, as shown in FIG. 1, the shape of the bushing 13 and the holder 14 of the conventional high voltage connecting device of the image forming apparatus is inferior in manufacturability. In addition, since the bushing 13 must be inserted into the receiving groove 14a and the protrusion 14b of the holder 14 at the same time, the assemblability is also reduced.

Accordingly, it is an object of the present invention to provide an electrophotographic image forming apparatus having a high voltage connection device having improved single product manufacturing and assembly properties.

According to the present invention, there is provided an electrophotographic image forming apparatus comprising: a rotating roller having a rotating shaft made of a conductive material; A high voltage generator; A frame supporting the rotating roller; An elastic material made of a conductive material interposed between the frame and the rotating roller to elastically press the rotating roller in a predetermined direction, and being connected to the rotating shaft of the rotating roller to receive the high voltage of the high voltage generator and transmit the received high voltage to the rotating shaft. It is achieved by an electrophotographic image forming apparatus comprising a member.

In addition, the elastic member is preferably in contact with the outer circumferential surface of the rotary shaft of the rotary roller so that the contact with the rotary shaft can be smoothly maintained even if the rotary roller rotates.
The apparatus may further include a crimping part provided on the frame to compress both ends of the contact part of the elastic member contacting the outer circumference of the rotating shaft.

In addition, the elastic member is one end of the coil spring is in contact with the outer circumferential surface of the rotating shaft in the circumferential direction of the rotating shaft of the rotating roller, the other end is supported by the frame, extending from the other end to the high voltage It may have a connection extension electrically connected to the generator.

In addition, it further comprises a cylindrical bushing for receiving the end of the rotary shaft of the rotary roller, the elastic member is preferably in contact with the outer peripheral surface of the bushing.

Here, further comprising a holder having a bushing receiving portion for receiving the bushing, and a projection protruding from the bushing receiving portion, wherein the elastic member is in contact with the outer peripheral surface of the bushing in the circumferential direction of the bushing A contact portion, an elastic pressing portion extending from the circumferential contact portion and inserted into the protrusion of the holder to elastically press the rotating roller in a predetermined direction, and a connecting extension portion extending from the elastic pressing portion and electrically connected to the high voltage generator. It is desirable to have.

In addition, the circumferential contact portion of the elastic member may be contacted in the circumferential direction to the outer peripheral surface of the bushing protruding in the longitudinal direction of the rotary roller from the bushing receiving portion of the holder.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the electrophotographic image forming apparatus 100 according to the present invention.

The image forming apparatus 100 according to the present invention includes a photosensitive drum 105, as shown in FIG. An exposure unit 102 for scanning light onto the surface layer 105b of the photosensitive drum 105; A rotating roller 110 including a charging roller 111, a developing roller 113, a transfer roller 115, and a cleaning roller 117; A high voltage generator (HVPS) 120 for generating a high voltage to respectively charge the surface of the rotary roller 110 to a predetermined potential; Interposed between the rotary roller 110 and the high voltage generator 120 to elastically press the rotary roller 110 to the photosensitive drum 105 at the same time to transfer the potential generated by the high voltage generator 120 to the rotary roller 110. It comprises a high voltage connection device 130.

The photosensitive drum 105 has a surface layer 105b coated with a photosensitive material on the outer circumferential surface of the metallic support 105b.

The rotary roller 110 includes a charging roller 111 for charging the surface of the photosensitive drum 105 to a predetermined potential; A developing roller 113 for applying a developer (toner) to an electrostatic latent image of the surface of the photosensitive drum 105 formed by the light scanned by the exposure unit 102; A transfer roller 115 for transferring the toner to the print medium P; And a cleaning roller 117 to remove residual toner debris on the surface of the photosensitive drum 105 after being transferred. When a cleaning blade (not shown) for scraping and removing residual toner on the surface of the photosensitive drum 105 is used, the cleaning roller 117 can be omitted.

The rotary roller 110 is an elastic surface layer (111b, 113b, 115b, 117b) of a conductive or semiconductive material surrounding the rotating shafts (111a, 113a, 115a, 117a) of the conductive material and the rotating shafts (111a, 113a, 115a, 117a). Has The surface layers 111b, 113b, 115b, and 117b rotate in contact with the photosensitive member 105b formed of the photosensitive material of the photosensitive drum 105.

In the case of forming the image by causing the toner to be negatively charged, the surface of the charging roller 111 is usually charged with (−) thousands of V (for example, (−) 1500 V), and thus the photosensitive drum 105 ) Surface layer 105a is charged to a uniform surface potential of lower (-) several hundred V (eg, (-) 800 V). An electrostatic latent image is formed on the photosensitive drum 105 by exposing only the portion corresponding to the image area to be printed by the exposure unit 102. At this time, the surface potential formed by charging is maintained in the unexposed portion, and the exposed portion is changed in potential, thereby forming an electrostatic latent image having a potential difference between the non-exposed portion and the exposed portion. For example, the exposure region has a potential of + 40V to -40V, while the non-exposure region has a negative potential of 800 V, which is the original surface potential. On the other hand, the charging potential of the developing roller 113 is determined by the value between the potential of the exposure area and the potential of the non-exposed area. For example, in the case of having the potential difference between the exposure and non-exposure regions, the developing roller 113 can be charged to about -450 V between +40 to -40 V to (-) 800 V. This value is the value selected by experiment or experience. On the other hand, the negatively charged toner buried in the developing roller 113 moves to a relatively high potential exposure area, and a toner image is formed on the outer circumferential surface of the surface layer 105a of the photosensitive drum 105. Since the transfer roller 115 is usually charged at (+) 800 to (+) 1500 V, the toner image on the surface of the photosensitive drum 105 is transferred to the print medium P by electrical attraction. . The toner image on the transferred print medium P is fixed to the print medium P by heat and pressure by a fixing roller (not shown) and then discharged to the outside of the image forming apparatus.

The high voltage generator 120 generates a high voltage to charge the surface of each of the rotary rollers 110 to a predetermined potential. Since the electric potential required for each rotary roller 110 is different, it is preferable that a high voltage of various sizes can be output correspondingly. The high voltage generator 120 is implemented in the form of a board in which a plurality of electronic devices are mounted on a circuit board and installed in the image forming apparatus 100.

Meanwhile, as shown in FIGS. 2 and 3, the high voltage connection device 130 not only receives and transmits the high voltage generated by the high voltage generator 120 to each rotary roller 110, but also transmits the rotary roller 110. It serves to elastically press the photosensitive drum 105 side. Of course, unlike shown, it is also possible to elastically press the rotating roller 110 in a predetermined other direction other than the photosensitive drum 105 side. For example, when the cleaning roller 117 is used as a means for cleaning the remaining toner of the transfer belt other than the photosensitive drum 105, it serves to elastically press the transfer belt side. That is, the high voltage connection device 130 is elastically pressurized to the target side to be in contact with each rotary roller 110 in accordance with the function of each rotary roller 110. As shown in FIG. 2, the high voltage connection device 130 is preferably provided in each rotating roller 110 in terms of component compatibility, but may be applied only to some rotating rollers 110 in some cases.

3 to 6 will be described with an example that the high voltage connection device 130 is installed on the cleaning roller 117 of the rotating roller 110 as an example. Of course, it can be applied to other rotating rollers 113 and 115 in addition to the cleaning roller 117.

As shown in FIGS. 3 and 4B, the high voltage connection device 130 includes a cylindrical bushing 133 that receives an end portion of the rotating shaft 117a of the cleaning roller 117, a bushing 133, and a high voltage generator ( The first elastic member 131 for elastically pressing the bushing 133 while electrically connecting 120. If the bushing 133 is omitted as necessary, the first elastic member 131 may be directly connected to the rotating shaft 110a of the cleaning roller 117. The first elastic member 131 serves to transfer the high voltage of the high voltage generator 120 to the rotating shaft 117a, and thus is provided with a conductive material.

In addition, the first elastic member 131 has a circumferential contact portion 131a, an elastic pressing portion 131b, and a connection extension portion 131c, as shown in Figs.

The circumferential contact portion 131a is in contact with the outer circumferential surface of the bushing 133 or the rotating shaft 117a along the circumferential direction of the rotating shaft 117a of the bushing 133 or the cleaning roller 117, respectively. The circumferential contact portion 131a is preferably provided in an annular ring shape so that the connection state with the bushing 133 or the rotating shaft 117a can be maintained even if the cleaning roller 117 rotates. As a result, even when the high voltage generator 120 and the cleaning roller 117 rotate, the electrical connection state between them can be maintained without being interrupted. In addition, both ends of the circumferential contact portion 131a are crimped and supported by the circumferential contact portion crimp portion 135c of the holder 135 to be described later. Accordingly, even if the circumferential contact portion 131a is deformed due to other reasons such as long time use, the contact state with the outer circumferential surface of the bushing 133 or the rotating shaft 117a can be maintained.

3 and 4, the elastic pressing portion 131b extends from the circumferential contact portion 131a to elastically press the rotating shaft 117a of the cleaning roller 117 in a predetermined direction A. As shown in FIG. The predetermined direction A is in the direction of the photosensitive drum 105, and preferably in the radial direction passing through the center of rotation of the photosensitive drum 105. In some cases, the predetermined direction A may vary depending on the function of each rotating roller 110. The elastic pressing unit 131b is preferably provided in a coil shape to be inserted into the protrusion 135b of the holder 135 to be described later in terms of manufacturability and assembly. If necessary, it may be provided in a plate shape and other shapes capable of elastic pressing in a predetermined direction. As shown in FIG. 5, the elastic pressing unit 131b is mounted on the seating unit 103a of the frame 103. If necessary, an accommodating groove (not shown) may be formed in the frame 103 so that one end of the elastic pressing portion 131b may be inserted into the accommodating groove (not shown). As long as the elastic pressing unit 131b is capable of applying an elastic force to the cleaning roller 117, the elastic pressing unit 131b may be supported by the frame 103 in any manner.

The frame 103 is provided inside a main body (not shown) of the image forming apparatus 100. It may be provided to be detachable from the main body (not shown) of the image forming apparatus 100 as part of the developer cartridge. The frame 103 is provided to support the rotating roller 110, as shown in Figs. If necessary, the frame 103 may accommodate the high voltage generator 120. When the high voltage generator 120 is not accommodated in the frame 103 and is outside, as shown in FIGS. 5 and 6, the high voltage generator 120 and the first elastic member 131 are connected to the frame 103. An opening 103b may be provided for the connection extension part 131c for electrically connecting the s.

3 to 4b, the connection extension part 131c is preferably extended from the elastic pressing part 131b in terms of productivity and is provided integrally with the elastic pressing part 131b. The connection extension part 131c may extend from the circumferential contact part 131a without being extended from the elastic pressing part 131b, as illustrated. Since the entire first elastic member 131 is made of a conductive material, a high voltage can be transmitted to the rotating shaft 117a of the cleaning roller 117, and thus may be connected to any portion of the first elastic member 131.

The connection extension part 131c may be provided to protrude into the opening 103b of the frame 103, as shown in FIGS. 5 and 6. The high voltage of the high voltage generator 120 may be transmitted to the first elastic member 131 by connecting the end of the protruding connection extension portion 131c and the high voltage generator 120. When the frame 103 is provided to be attached to or detached from the main body (not shown) of the image forming apparatus 100, an electrical connection part (not shown) made of a conductive material is provided in one region of the frame 103 as needed to connect with the electrical connection part. The extension 131c may be connected. In addition, the main body (not shown) of the image forming apparatus 100 may be provided with a high voltage applying part through which a high voltage of the high voltage generating device 120 is transmitted to correspond to the electrical connection part (not shown). It can also be electrically connected and disconnected. In addition, the connection extension part 131c and the high voltage generator 120 may be connected by a conventional method known in the art.

The high voltage connection device 130 of the image forming apparatus 100 according to the present invention may further include a bushing 133 and a holder 135.

3 to 4B, the bushing 133 may include a cylindrical portion 133a and a rotating shaft 110a of the rotary roller 110 inserted into the insertion hole 135f of the holder 135 to be described later. It has a bearing part 133b which accommodates one end part. It is preferable that the edge 133c of the insertion cylindrical portion 133a is curved, so that the insertion cylindrical portion 133a can be easily inserted into the circumferential contact portion 131a of the first elastic member 131 during assembly.

As shown in FIGS. 3 to 4B, the holder 135 includes a bushing accommodating part 135a for accommodating a part of the bushing 133, a protrusion 135b protruding from the accommodating part 135a, and a accommodating part. A circumferential contact portion 135d that extends in the longitudinal direction of the bushing 133 at 135a to receive the circumferential contact portion 131a of the first elastic member 131 and a circumference for crimping both ends of the circumferential contact portion 131a. A contact crimp 135c.

Holder 135 is formed of a non-conductive plastic material, preferably formed integrally with the productivity side.

Between the bushing accommodating part 135a and the circumferential contact part accommodating part 135d, the horizontal plate 135e which prevents longitudinal separation of the cleaning roller 117 is provided.

The bushing accommodating part 135a receives the insertion cylindrical part 133a of the bushing 133. The predetermined region of the end portion of the insertion cylindrical portion 133a accommodated in the bushing accommodation portion 135a may receive the circumferential contact portion 131a of the first elastic member 131 through the insertion hole 135f formed in the horizontal plate 135e. It protrudes to the circumferential contact part accommodating part 135d side.

The elastic pressing portion 131b of the first elastic member 131 is inserted into the protrusion 135b. The protrusion 135b prevents the first elastic member 131 from being separated and elastically presses the cleaning roller 117 in the protruding direction of the protrusion 135b.

The circumferential contact portion receiving portion 135d is provided to have an inner space having a shape corresponding to the shape of the circumferential contact portion 131a in order to suppress vibration or fine movement of the circumferential contact portion 131a during the rotation of the cleaning roller 117. desirable.

The circumferential contact portion crimping portion 135c compresses both ends of the circumferential contact portion 131a of the first elastic member 131, as shown in FIG. 4A. Preferably, the distance d2 between the circumferential contact portions crimping portion 135c is smaller than the distance d1 between the circumferential contact portions 131a. By pressing both ends of the circumferential contact portion 131a, even if the bushing 133 rotates, the circumferential contact portion 131a can be brought into contact with the outer circumferential surface of the insertion cylindrical portion 133a of the bushing 133. If necessary, the circumferential contact portion crimping portion 135c may be provided in the frame 103 instead of the holder 135.

Hereinafter, the assembling process of the high voltage connection device 130 will be described with reference to FIGS. 4A and 4B.

As shown in FIG. 4A, the elastic pressing portion 131b of the first elastic member 131 is inserted into the protrusion 135b of the holder 135.

Then, as shown in FIG. 4B, the circumferential contact portion 131a is pressed while contacting the circumferential contact portion compression portion 135c of the holder 135 as the elastic pressing portion 131b is inserted into the protrusion 135b. Finally, it is accommodated in the circumferential contact receiving portion 135d. Then, both ends of the circumferential contact portion 131a of the first elastic member 131 are squeezed by the circumferential contact portion crimp portion 135c so that the diameter of the circumferential contact portion 131a is accommodated in the holder 135 rather than in a single state. do. Thus, in the assembled state, the diameter of the circumferential contact portion 131a becomes somewhat smaller than the diameter of the insertion cylindrical portion 133a of the bushing 133.

Next, when the assembly of the bushing 133 inserted at the end of the rotating roller rotating shaft (not shown) is inserted into the bushing receiving portion 135a of the holder 135, the bushing 133 passes through the insertion hole 135f. The insertion cylinder portion 133a is protruded. In addition, the insertion cylindrical portion 133a may be easily inserted into the circumferential contact portion 131a of the first elastic member 131 because the entry side edge 133c is curved. As a result, the circumferential contact portion 131a of the first elastic member 131 comes into contact with the outer circumferential surface of the insertion cylindrical portion 133a of the bushing 133.

And, since the circumferential contact portion crimping portion 135c compresses both ends of the circumferential contact portion 131a, even if the bushing 133 rotates together with the rotary roller 110, the high voltage of the high voltage generator 120 without the contact failure is the rotation roller ( It may be transmitted to the rotating shaft 110a of the 110.

When the high voltage connecting device 130 is installed at one end of the rotary roller 110, the opposite end of the rotating roller 110, as shown in Figure 6, the first elastic member of the high voltage connecting device 130 ( A device for elastically pressing the rotating roller 110 in the same direction as 131 is installed. That is, the device consisting of the bushing 133, the second elastic member 141 and the holder 135 is installed at the opposite end of the rotary roller 110. The second elastic member 141 is a coil spring and is inserted into the protrusion 135b of the holder 135. The second elastic member 141 only serves to elastically press the rotary roller 110 and does not perform a role of transmitting a high voltage of the high voltage generator 120. Therefore, it may be formed of a non-conductive material, and the circumferential contact portion 131a and the connection extension portion 131c of the first elastic member 131 need not be provided.

As shown in FIG. 6, the bushing 133 and the holder 135 of the high voltage connection device 130 installed at the opposite end of the rotary roller 110 are used to share parts in order to reduce manufacturing cost. If necessary, the members may be omitted or may be replaced with other members. That is, it is sufficient that the rotary roller 110 can be elastically pressed in the same direction as the first elastic member 131 of the high voltage connection device 130. The rotating roller 110 is not only elastically pressurized in a predetermined direction by the above-described components, but also a high voltage of the high voltage generator 120 is applied to allow the surface to be charged to a predetermined potential.

As described above, according to the image forming apparatus according to the present invention, the following effects can be obtained.

First, it is possible to simplify the structure of the high voltage connection device to improve the productivity and assemblability of the unit production. In addition, product cost can be reduced.

Second, the high voltage of the high voltage generating device can be stably transmitted to the rotating shaft of the rotating roller.

Claims (9)

In the electrophotographic image forming apparatus, A rotating roller having a rotating shaft made of a conductive material; A high voltage generator; A holder having a receptacle for supporting the rotating roller and a protrusion supported on the frame; A circumferential contact portion in contact with the outer circumferential surface of the rotating shaft, an elastic pressure portion extending from the circumferential contact portion, inserted into the protrusion of the holder, and elastically pressing the rotary roller in a predetermined direction, and extending from the elastic pressure portion to generate the high voltage. An electrophotographic image forming apparatus comprising an elastic member having a connecting extension electrically connected to the apparatus. The method of claim 1, And a crimping portion provided on the holder to press the circumferential contact portion of the elastic member to be in contact with the outer circumference of the rotating shaft. delete In the electrophotographic image forming apparatus, A rotating roller having a rotating shaft made of a conductive material; A high voltage generator; A cylindrical bushing for receiving an end portion of the rotating shaft of the rotating roller; A holder accommodating and supporting the bushing, and a holder formed with a protrusion supported by the frame; A circumferential contact portion in contact with the outer circumferential surface of the bushing, an elastic pressure portion extending from the circumferential contact portion, inserted into the protrusion of the holder, and elastically pressing the rotary roller in a predetermined direction, and extending from the elastic pressure portion to generate the high voltage. An electrophotographic image forming apparatus comprising an elastic member having a connecting extension electrically connected to the apparatus. delete delete In the electrophotographic image forming apparatus, A rotating roller having a rotating shaft made of a conductive material; A high voltage generator; A holder for supporting the rotating shaft of the rotating roller; A circumferential contact portion interposed between the frame and the holder, the circumferential contact portion contacting to surround the outer circumferential surface of the rotating shaft supported by the holder, an elastic pressing portion extending from the circumferential contact portion to elastically press the rotating roller in a predetermined direction, and the elasticity. An electrophotographic image forming apparatus comprising: an elastic member extending from the pressing portion and having a connection extension portion electrically connected to the high voltage generator. In the electrophotographic image forming apparatus, A rotating roller having a rotating shaft made of a conductive material; A high voltage generator; A cylindrical bushing for receiving an end portion of the rotating shaft of the rotating roller; A holder for receiving and supporting the bushing; A circumferential contact portion interposed between the frame and the holder, the circumferential contact portion contacting to surround the outer circumferential surface of the bushing supported by the holder, an elastic pressing portion extending from the circumferential contact portion to elastically press the rotating roller in a predetermined direction, and the elasticity An electrophotographic image forming apparatus comprising: an elastic member extending from the pressing portion and having a connection extension portion electrically connected to the high voltage generator. The method according to any one of claims 4 to 7, wherein And a crimping portion provided on the holder to press the circumferential contact portion of the elastic member.

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