JP2022127357A - Sheet conveying device, image forming apparatus, and assembling method for grounding unit - Google Patents

Abstract

To provide a sheet conveying device, an image forming apparatus, and an assembling method for a grounding unit that can improve the assemblability of components for grounding the rotation shaft in the transport roller and properly conduct the components to each other.SOLUTION: In the inventive embodiment, a grounding unit 7 for grounding a resist roller 35b to a grounding member 4 comprises: a first ground spring 71 that conducts to the resist roller 35b; a second ground spring 72 that conducts to the grounding member 4; and a spring holder 73 that holds both the first ground spring 71 and the second ground spring 72 and is attached to a device body 2, wherein the spring holder 73 has a first holding portion 73a holding the first ground spring 71 and a second holding portion 73b holding the second ground spring 72, and, in a state where the first ground spring 71 is held by the first holding portion 73a and the second ground spring 72 is held by the second holding portion 72b, the first ground spring 71 and the second ground spring 72 are in contact with each other and are electrically connected.SELECTED DRAWING: Figure 3

Description

The present invention relates to a sheet conveying device, an image forming apparatus, and a method for assembling a grounding unit.

Conventionally, in a sheet conveying device provided in an image forming apparatus, a conveying roller is used for conveying a sheet, and when the rotating shaft of the conveying roller is made of metal, it is necessary to ground the rotating shaft. .

Various configurations for grounding the rotating shaft have been devised. For example, in Japanese Unexamined Patent Application Publication No. 2002-100000, the rotating shaft is grounded by electrically connecting the rotating shaft of the conveying roller and a metal reinforcing member using a grounding member made of spring steel or the like.

Further, in Patent Document 2, a metal plate spring that is grounded on a metal structure is directly pressed against a metal rotating shaft, so that the rotating shaft and the structure are electrically connected to each other. I am grounded.

JP 2019-026406 A Japanese Patent Application Laid-Open No. 2001-341881

As described above, when grounding the rotating shaft of the transport roller, it is necessary to connect a plurality of members to establish electrical continuity. may occur, which may complicate the assembly of the parts. In addition, if the assembly of the members becomes complicated, the connected members are not properly connected to each other, and the grounding of the rotating shaft becomes incomplete. may cause it to occur.

Therefore, in the present invention, an assembly of a sheet conveying apparatus, an image forming apparatus, and a grounding unit is provided, which is capable of improving the assembling property of the members for grounding the rotating shaft of the conveying roller, and allowing the members to be properly connected to each other. provide a mounting method.

The problems to be solved by the present invention are as described above, and the means for solving the problems will now be described.

That is, a sheet conveying apparatus according to the present invention has a housing and a metal rotating shaft, is held by the housing via the rotating shaft, and includes a conveying roller that conveys a sheet and a roller that is held by the housing. and a grounding unit that connects the conveying roller and the grounding member and grounds the conveying roller to the grounding member, wherein the grounding unit is a first grounding member electrically connected to the conveying roller. a ground spring; a second ground spring electrically connected to the ground member; and a spring holder that holds both the first ground spring and the second ground spring and is attached to the housing, wherein the spring holder holds the first ground spring. and a second holding portion for holding the second earth spring, wherein the first holding portion holds the first earth spring, and the second holding portion holds the second earth spring. In the closed state, the first earth spring and the second earth spring are in contact with each other and are electrically connected.

Thus, in the sheet conveying device according to the present invention, the spring holder is provided with the first holding portion that holds the first earth spring and the second holding portion that holds the second earth spring. and the second ground spring can be attached to the housing through the spring holder in a state of being integrally held in advance by the spring holder.
Therefore, the first and second earth springs, which are the plurality of members provided for grounding the conveying roller, can be easily assembled to the housing, and the work of assembling the first and second earth springs can be easily performed. It is possible to improve the quality.
In addition, since the first and second earth springs are held by the spring holder, they come into contact with each other and are electrically connected. Continuity can be properly ensured.
Furthermore, as described above, when the first and second earth springs are held by the spring holders, the state of continuity between the first and second earth springs is established. The conduction state can be easily confirmed without waiting for.

Further, in the sheet conveying device according to the present invention, the first earth spring is a cylindrical compression coil spring, and the first holding portion is adapted to move the first earth spring in a first direction that is a radial direction of the first earth spring. It is preferable to have a pair of ridges arranged at a sandwiching position and opposed to each other with a gap smaller than the outer diameter of the first earth spring in the natural state.

With such a configuration, one end of the first ground spring in the axial direction can be sandwiched between the pair of ridges, and the first ground spring can be securely held in the spring holder via the first holding part.

Further, in the sheet conveying device according to the present invention, the second holding portions are arranged at positions sandwiching the first earth spring in a second direction perpendicular to the first direction, respectively. It is preferable to have a part and a second hook part.

With such a configuration, the second earth spring is held in the spring holder by the second holding portion composed of the first and second engaging portions in a state where the second earth spring crosses the first earth spring. , the first earth spring and the second earth spring can be reliably brought into contact with each other, and the conductive state between both members (the first earth spring and the second earth spring) can be easily ensured.

Further, in the sheet conveying device according to the present invention, in the second holding portion, the first hooking portion has a groove into which the second earth spring can be fitted, It is preferable to have a protrusion that can be engaged with two earth springs.

With such a configuration, it is possible to easily regulate the arrangement position of the second earth spring with respect to the spring holder by fitting it into the groove provided in the first engaging portion, and the second earth spring provided in the second engaging portion can be easily regulated. The second earth spring can be securely held in the spring holder by engaging the projection on the spring holder.

Further, in the sheet conveying device according to the present invention, the protrusion of the second hooking portion is inclined in a direction away from the first hooking portion toward the side on which the second earth spring is hooked. It is preferable to have an inclined surface for guiding the second earth spring when engaging the earth spring.

With such a configuration, when the second holding portion holds the second earth spring in the spring holder, the second earth spring is guided to the projection via the inclined surface, and the second earth spring can be easily hooked to the projection. can be made

Also, in the sheet conveying device according to the present invention, the second earth spring includes a first extending portion that extends along the first direction and is latched by the first latching portion, and the second latching portion. a second extending portion that is hooked to the stop portion; and a third extending portion and a fourth extending portion that extend along the second direction; The distance between the projecting portion and the fourth extending portion is smaller than the outer diameter of the first earth spring, and the distance between the first extending portion and the second extending portion in the second direction is The distance is preferably greater than the outer diameter of the first earth spring.

With such a configuration, when viewed in the axial direction of the first earth spring, both the third extension and the fourth extension of the second earth spring intersect with the first earth spring, and the axis of the first earth spring It is arranged in a state in which it has two points of contact with each of the directional tip portions, so that the conductive state between the first earth spring and the second earth spring can be ensured more reliably.

Further, in the sheet conveying apparatus according to the present invention, the spring holder has a projecting portion that is inserted into the inner diameter portion of the first ground spring and regulates the position of the first ground spring, and the projecting portion A pair of regulating surfaces may be provided on both sides in the direction, respectively, which abut against the third extension and the fourth extension of the second earth spring to regulate the position of the second earth spring in the first direction. preferable.

By having such a configuration, the arrangement positions of the first earth spring and the second earth spring held by the spring holder are regulated so as to be at a predetermined position, and the conduction state between the first earth spring and the second earth spring is It can be secured more reliably.

Further, an image forming apparatus according to the present invention includes any one of the sheet conveying devices described above and an image forming section that forms an image on the sheet conveyed by the sheet conveying device.
Further, a method for assembling a grounding unit according to the present invention is a method for assembling a grounding unit provided in any one of the above-described sheet conveying apparatuses or the above-described image forming apparatus, wherein the second grounding spring 2 a first step of holding the first earth spring in the spring holder by the holding portion and then holding the first earth spring in the spring holder by the first holding portion to assemble the earth unit; and the earth assembled in the first step. and a second step of assembling the unit to the housing.

As described above, in the image forming apparatus and the method for assembling the grounding unit according to the present invention, the spring holder is provided with the first holding portion that holds the first ground spring and the second holding portion that holds the second ground spring. The first earth spring and the second earth spring can be attached to the housing through the spring holder in a state in which they are integrally held in advance by the spring holder.
Therefore, the first and second earth springs, which are the plurality of members provided for grounding the conveying roller, can be easily assembled to the housing, and the work of assembling the first and second earth springs can be easily performed. It is possible to improve the quality.
Further, since the first earth spring and the second earth spring are held by the spring holder, they are brought into contact with each other and are in an electrically conductive state. Conduction of the member can be properly ensured.
Furthermore, as described above, when the first and second grounding members are held by the spring holders, the conductive state between the first and second grounding members is established. The conduction state can be easily confirmed without waiting for assembly.

As effects of the present invention, the following effects are obtained.
According to the sheet conveying apparatus, the image forming apparatus, and the method for assembling the grounding unit according to the present invention, it is possible to improve the assembling property of the member for grounding the rotating shaft of the conveying roller, and to properly conduct the members. be able to.

1 is a cross-sectional side view showing the overall configuration of an image forming apparatus according to one embodiment of the present invention; FIG. 2 is an enlarged cross-sectional side view mainly showing the configuration in the vicinity of a grounding unit in the image forming apparatus; FIG. FIG. 4 is a side view showing the configuration of the grounding unit; It is a perspective view showing the configuration of the ground unit. FIG. 4 is an enlarged perspective view mainly showing the configuration of the first hooking portion and the holder-side projecting portion in the grounding unit. FIG. 6 is a diagram mainly showing the configuration of a second holding portion in the grounding unit, viewed from one side in the first direction in FIG. 5 ; FIG. 10 is a view showing the configuration of the grounding unit, viewed from the projecting direction side of the holder-side projecting portion. It is a figure for demonstrating the assembly|attachment method of an earth unit.

Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 8. FIG.
1 to 3, the direction in which the sheet S is ejected onto the paper ejection tray 23b is defined as the front side in FIGS. , the directions of the arrows shown in each drawing define and describe the front-back direction, the left-right direction, and the up-down direction of the image forming apparatus 1 .

[Image forming apparatus 1]
First, the overall configuration of an image forming apparatus 1 according to this embodiment will be described with reference to FIGS. 1 and 2. FIG.
In FIG. 1, an image forming apparatus 1 is an embodiment of the image forming apparatus according to the present invention, and is a color laser printer that forms images of multiple colors on a sheet S by electrophotography.

The image forming apparatus 1 includes a sheet feeding unit 3 having a sheet feeding tray 10 for supporting a sheet S and a sheet conveying device 30 for conveying the sheet S, and an image forming unit for forming an image on the sheet S conveyed by the sheet conveying device 30. a part 5; The sheet conveying apparatus 30 includes an apparatus main body 2 as an example of a housing, a registration roller 35b as an example of a conveying roller for conveying the sheet S and described later, a metal grounding member 4, and a registration roller 35b. A grounding unit 7 is provided for grounding the grounding member 4 .

The apparatus main body 2 is formed in a substantially rectangular parallelepiped shape, and accommodates the paper feeding section 3 and the image forming section 5 . An opening 2A is opened in the upper surface of the apparatus main body 2, and the apparatus main body 2 has a top cover 23 capable of opening and closing the opening 2A.

The top cover 23 is configured to be rotatable about a rotating shaft 23a at its rear end, and rotates about the rotating shaft 23a to move between a closed position for closing the opening 2A and a closed position for closing the opening 2A. It is movable between an open position to open 2A. A top cover 23 of the apparatus main body 2 is formed with a discharge tray 23b that slopes downward from the front side to the rear side.

The sheet conveying device 30 also has a conveying frame 24 which is a part of the device main body 2 . The conveying frame 24 extends in the left-right direction and has a substantially L-shape in a side view with a lower end protruding rearward, and is attached to the front portion of the apparatus main body 2 .

The conveying frame 24 holds a registration roller 35a and a registration roller 35b, an earthing unit 7, etc., which will be described later, thereby forming the sheet conveying device 30. As shown in FIG.

The grounding member 4 is made of a substantially rectangular sheet-metal-processed plate-like member, and is held by the apparatus main body 2 in the upper front portion of the apparatus main body 2 in a state in which the plate surface faces in the front-rear direction and is laterally suspended in the left-right direction. It is The ground member 4 is grounded.

The paper feeding section 3 is arranged in the lower part of the apparatus main body 2 and conveys the sheet S supported by the paper feeding tray 10 to the image forming section 5 by the sheet conveying device 30 . The paper feed tray 10 is configured to be slidable in the front-rear direction, and is configured to be movable between an accommodation position accommodated in the apparatus main body 2 and a separation position pulled forward from the accommodation position.

The sheet conveying device 30 further includes a feed roller 32, a separation roller 33, a separation pad 33a, a conveying roller 34a, and a registration roller 35a. In the apparatus main body 2, a conveying path P for the sheet S is configured from the paper feed tray 10 to the paper discharge tray 23b via the image forming section 5. As shown in FIG.

The sheets S supported by the paper feed tray 10 are separated one by one by the paper feed roller 32, the separation roller 33, and the separation pad 33a, and sent to the transport path P. As shown in FIG. The paper feed roller 32 is a roller that conveys the sheet S from the paper feed tray 10 toward the image forming section 5 . The separation roller 33 and the separation pad 33a constitute separation means for separating the sheets S supported by the paper feed tray 10 one by one.

The sheet S sent to the conveying path P is conveyed to the image forming section 5 by a conveying roller 34a and a roller 34b arranged to face the conveying roller 34a, and a registration roller 35a and a registration roller 35b arranged to face the registration roller 35a. transported towards The registration rollers 35a and the registration rollers 35b regulate the movement of the leading edge of the conveyed sheet S in a sandwiched state and temporarily stop it, and then convey the sheet S toward the image forming unit 5 at a predetermined timing. . The registration rollers 35b are held by the conveying frame 24 of the apparatus main body 2 via a metallic rotary shaft 36 (see FIG. 2) while being pressed against the registration rollers 35a.

Here, as shown in FIG. 2, a plurality of grounding members (a first grounding spring 71 and a second grounding spring 72, which will be described later) are integrally held in advance at the end of the rotating shaft 36 of the registration roller 35b. , and the rotation shaft 36 of the registration roller 35b is connected to the ground member 4 through the ground unit 7 and grounded to the ground member 4. As shown in FIG.
A detailed configuration of the ground unit 7 will be described later.

In FIG. 1, the image forming section 5 is arranged above the paper feeding section 3 and has four process cartridges 50 arranged side by side in the front-rear direction. Each process cartridge 50 is provided for each color of black, yellow, magenta, and cyan. The process cartridge 50 is detachably attached to the apparatus main body 2 . The process cartridge 50 includes a photosensitive drum 51 , a developing roller 52 , a supply roller 53 and a charger 54 .

The process cartridge 50 is mounted in the apparatus main body 2 in such a posture that the axis of the photosensitive drum 51 extends in the horizontal direction. The horizontal direction is an example of the axial direction. The developing roller 52 is configured to be movable between a contact position where it contacts the photosensitive drum 51 and a separated position where it separates from the photosensitive drum 51 . The supply roller 53 supplies toner contained in the process cartridge 50 to the developing roller 52 .

The apparatus main body 2 has an exposure head 59 that exposes the surface of the photosensitive drum 51 . The exposure head 59 is supported by the top cover 23 . Four exposure heads 59 are provided corresponding to each photosensitive drum 51, and each exposure head 59 is arranged side by side in the front-rear direction. The exposure head 59 extends downward from the top cover 23 and has an exposure portion 59a at its lower end. The exposure unit 59a is arranged above and close to the photosensitive drum 51 when the top cover 23 is closed. The exposure unit 59a is configured by an LED array having a plurality of LED elements arranged side by side in the left-right direction.

A transfer belt 41 is arranged below the photosensitive drum 51 with the transport path P interposed therebetween. The transfer belt 41 is stretched between a drive roller 42 and a driven roller 43 arranged in front of the drive roller 42 . A belt device 40 is configured by the transfer belt 41 , the drive roller 42 , and the driven roller 43 . Transfer rollers 44 are arranged at positions facing the respective photosensitive drums 51 with the transfer belt 41 interposed therebetween.

In the image forming section 5 , the photosensitive drums 51 uniformly charged by the charger 54 are selectively exposed by the exposure heads 59 . This exposure selectively removes charges from the surface of the photosensitive drum 51 and forms an electrostatic latent image on the surface of the photosensitive drum 51 .

The toner contained in the process cartridge 50 is positively charged between the supply roller 53 and the developing roller 52 and carried on the surface of the developing roller 52 . A developing bias is applied to the developing roller 52 , and when the electrostatic latent image formed on the photosensitive drum 51 faces the developing roller 52 , the potential difference between the electrostatic latent image and the developing roller 52 causes the developing roller 52 to supplies toner to the electrostatic latent image. Thereby, a toner image is formed on the surface of the photosensitive drum 51 .

When the sheet S conveyed toward the image forming unit 5 reaches the transfer belt 41 , it is conveyed by the transfer belt 41 and sequentially passes between the transfer belt 41 and each photosensitive drum 51 . Then, the toner image on the surface of the photosensitive drum 51 is transferred onto the sheet S by the transfer bias applied to the transfer roller 44 when facing the sheet S. As shown in FIG.

In this embodiment, the transfer belt 41 is configured as a conveying belt that conveys the sheet S onto which the toner image is transferred. It is also possible to construct an intermediate transfer belt to be transferred to S.

The sheet S onto which the toner image has been transferred is conveyed to the fixing device 60 . The fixing device 60 has a heating roller 61 and a pressure roller 62 that presses against the heating roller 61 . The toner image is thermally fixed on the surface.

Then, the sheet S on which the toner image is thermally fixed is conveyed from the fixing device 60 to the downstream side in the conveying direction. It is conveyed by the paper roller pair 64 and discharged to the paper discharge tray 23b.

[Earth unit 7]
Next, the configuration of the earth unit 7 will be described in detail with reference to FIGS. 3 to 8. FIG.
As shown in FIG. 3, the grounding unit 7 mainly includes a first grounding spring 71 electrically connected to the rotating shaft 36 of the registration roller 35b, a second grounding spring 72 electrically connected to the grounding member 4, the first grounding spring 71 and the second grounding spring 72 electrically connected to the grounding member 4. and a spring holder 73 that holds the ground spring 72 together and is attached to the transport frame 24 of the apparatus main body 2 .

For example, in the present embodiment, the grounding unit 7 is provided on one side of the rotating shaft 36 in the axial direction (on the right side in the present embodiment). It may be provided on the other side in the direction (the left side in this embodiment), or may be provided on both sides (both left and right sides) of the rotating shaft 36 in the axial direction.

The first earth spring 71 is, for example, a cylindrical compression coil spring in this embodiment, held by a spring holder 73 at one end in the axial direction, and connected to the end of the rotating shaft 36 at the other end in the axial direction.

Here, both left and right ends of the rotating shaft 36 in the axial direction are rotatably supported by the conveying frame 24 of the apparatus main body 2 via bearings 37 formed of a conductive member.
Each bearing 37 is provided with a bearing-side protruding portion 37 a that protrudes in a direction perpendicular to the axial direction of the rotating shaft 36 .

The bearing-side protruding portion 37a of the one (right end) bearing 37 is inserted into the inner diameter portion of the first earth spring 71 on the other end side in the axial direction, and the bearing-side protruding portion 37a of the other (left end) bearing 37 is inserted. The portion 37a is inserted into the inner diameter portion of the compression coil spring (not shown) at the other end in the axial direction. 1).
Thereby, the first earth spring 71 is connected to the rotating shaft 36 via the bearing 37 and conducts with the rotating shaft 36 .

Similarly to the first earth spring 71, the second earth spring 72 is, for example, a cylindrical compression coil spring in this embodiment. provided to extend in the tangential direction of the The other axial end of the second earth spring 72 is in contact with the earth member 4 , whereby the second earth spring 72 is electrically connected to the earth member 4 .

The spring holder 73 has a first holding portion 73 a that holds the first earth spring 71 , a second holding portion 73 b that holds the second earth spring 72 , and a third holding portion 73 c that is held by the transport frame 24 .

As shown in FIGS. 4 and 7, the first holding portion 73a is arranged at a position sandwiching the first earth spring 71 in the first direction T1, which is the radial direction of the first earth spring 71 held by the spring holder 73. It has a pair of protrusions 73a1. That is, the pair of ridges 73 a 1 are provided at the center of the first earth spring 71 held by the spring holder 73 in the second direction T 2 orthogonal to the first direction T 1 and aligned with the axial center of the first earth spring 71 . , and are arranged to face each other with an interval H smaller than the outer diameter D of the first earth spring 71 in the natural state (D>H).

Between the pair of ridges 73a1, a protrusion (hereinafter referred to as , and “holder-side protrusion”) 73d are provided.

The holder-side projecting portion 73d is inserted into the inner diameter portion of the first earth spring 71 on the one end side in the axial direction, and the one end of the first earth spring 71 in the axial direction is inserted between the pair of ridges 73a1. It is arranged in the spring holder 73 .
As a result, the position of the first earth spring 71 with respect to the spring holder 73 is restricted by the holder-side projecting portion 73d, and one axial end of the first earth spring 71 is clamped by the pair of ridges 73a1. 73.

The second holding portion 73b is arranged at a position sandwiching the first earth spring 71 held by the first holding portion 73a in the second direction T2. 73b2.

As shown in FIG. 5, the first hooking portion 73b1 has a groove portion 74 extending along the first direction T1. It has a configuration in which the projecting portion 72a1) can be fitted.
In addition, as shown in FIG. 6, the second hooking portion 73b2 has a projecting portion 75 that projects to the side opposite to the first hooking portion 73b1 side in the second direction T2 (arrow X side in FIG. 6). Then, the second ground spring 72 (more specifically, a second extension 72a2 described later; see FIG. 4) is attached to the projection 75 on the side opposite to the first ground spring 71 (the arrow Y side in FIG. 6). ) can be engaged.

The projecting portion 75 of the second engaging portion 73b2 has an inclined surface that inclines in a direction away from the first engaging portion 73b1 (arrow X side) as it goes toward the engaging side (arrow Y side) of the second earth spring 72. When engaging the second earth spring 72 , the second earth spring 72 is slid along the inclined surface 75 a and guided to the position where it engages with the protrusion 75 .

With such a configuration, when the second holding portion 73b holds the second earth spring 72 in the spring holder 73, the inclined surface 75a guides the second earth spring 72 to the protrusion 75 of the second hooking portion 73b2, The second earth spring 72 can be easily hooked on the portion 75 .

On the other hand, as shown in FIG. 4, the distal end of the bent portion 72a of the second earth spring 72, in a state of being held by the spring holder 73, has a first extending portion 72a1 extending along the first direction T1 and a second extending portion 72a1 extending along the first direction T1. It is formed in a substantially rectangular frame shape including an extension portion 72a2, and a third extension portion 72a3 and a fourth extension portion 72a4 extending along the second direction T2. In other words, the distal end of the bent portion 72a of the second earth spring 72 is extended by the second extending portion 72a2, the third extending portion 72a3, the first extending portion 72a1, and the fourth extending portion 72a4 which are continuously provided in this order. It is bent into a rectangular shape.

The second earth spring 72 engages the first extending portion 72a1 with the groove portion 74 (see FIG. 5) of the first engaging portion 73b1, and the second extending portion 75 of the second engaging portion 73b2. By hooking the protruding portion 72a2, the spring holder 73 holds the base portion of the holder-side protruding portion 73d in a state where the root portion is sandwiched between the third extending portion 72a3 and the fourth extending portion 72a4.

The holder-side protruding portion 73d has a pair of restricting surfaces 73d1 on both sides in the first direction T1 that contact the third extending portion 72a3 and the fourth extending portion 72a4 of the second earth spring 72. The position of the second earth spring 72 in the first direction T1 is regulated by holding the root portion of the holder-side projecting portion 73d between the third projecting portion 72a3 and the fourth projecting portion 72a4.

As described above, in the present embodiment, the first engaging portion 73b1 and the second engaging portion 73b2 are arranged at positions sandwiching the first earth spring 71 held by the spring holder 73. The ground spring 72 is held in the spring holder 73 by a second holding portion 73b consisting of a first hooking portion 73b1 and a second hooking portion 73b2 in a state where the ground spring 72 intersects the first ground spring 71 at the distal end portion of the bent portion 72a. As a result, the first earth spring 71 and the second earth spring 72 can be reliably brought into contact with each other, and the conductive state between the first earth spring 71 and the second earth spring 72 can be easily ensured.

Further, when the second earth spring 72 is held in the spring holder 73, the arrangement position of the second earth spring 72 with respect to the spring holder 73 is adjusted by fitting the first extending portion 72a1 into the groove portion 74 of the first hooking portion 73b1. The second earth spring 72 can be reliably held in the spring holder 73 by engaging the second extending portion 72a2 with the protrusion 75 of the second engaging portion 73b2.

By the way, as shown in FIG. 7, in this embodiment, the distance L1 between the third extending portion 72a3 and the fourth extending portion 72a4 in the first direction T1 is larger than the outer diameter D of the first earth spring 71. is smaller (L1<D), and the distance L2 between the first extending portion 72a1 and the second extending portion 72a2 in the second direction T2 is greater than the outer diameter D of the first earth spring 71 (L2>D). is set to be

With such a configuration, when viewed in the axial direction of the first earth spring 71, the third extending portion 73a3 and the fourth extending portion 73a4 of the second earth spring 72 both intersect the first earth spring 71, The contact points P1 and P2 are arranged in contact with one end of the first earth spring 71 in the axial direction at two points, respectively. can be secured.

As shown in FIG. 4, a pair of third holding portions 73c are provided on both sides of the first earth spring 71 held by the spring holder 73 in the first direction T1. Each third holding portion 73c extends in the direction in which the holder-side projecting portion 73d protrudes, and a hooking portion 73c1 is formed at the tip of the third holding portion 73c toward the inside (that is, toward the first earth spring 71). there is

As shown in FIG. 3, a pair of hooked portions 21 are provided at predetermined locations in the vicinity of the bearings 37 of the transport frame 24. By engaging the engaging portion 73c1, the spring holder 73 is held by the conveying frame 24 via the third holding portion 73c.

The grounding unit 7 having such a configuration is attached to the apparatus main body 2 in a state in which the first grounding spring 71 and the second grounding spring 72 are attached to the spring holder 73 to be integrally assembled in advance.
That is, as shown in FIG. 8, the method of assembling the grounding unit 7 according to the present embodiment is such that after the second grounding spring 72 is held by the spring holder 73 by the second holding portion 73b, the first grounding spring 71 is attached to the first spring holder 73b. A first step of assembling the earth unit 7 by holding it in the spring holder 73 by the holding portion 73a and a second step of assembling the earth unit 7 assembled in the first step to the transfer frame 24 are provided.

In the first step, by holding the first earth spring 71 and the second earth spring 72 by the spring holder 73, one end of the first earth spring 71 (more specifically, the end on the holder-side protrusion 73d side) is connected to the second ground spring. The first earth spring 71 and the second earth spring 72 are brought into contact with the bent portion 72a (more specifically, the first extension portion 72a1 to the fourth extension portion 72a4) of the earth spring 72, and are electrically connected to each other.
Further, in the second step, by assembling the assembled grounding unit 7 to a predetermined position of the device main body 2 via the third holding portion 73c, the other end of the first grounding spring 71 is attached to the bearing-side projecting portion 37a. The other end of the second ground spring 72 (the end opposite to the bent portion 72a side) is connected to the ground. It comes into contact with the member 4 (see FIG. 2) and is in a conductive state with the ground member 4 .
As a result, the resist roller 35b is grounded to the grounding member 4 through the grounding unit 7. As shown in FIG.

As described above, the sheet conveying device 30 in this embodiment has the device powder 2 and the metal rotating shaft 23a, and is held by the conveying frame 24 of the device main body 2 via the rotating shaft 23a. a metal grounding member 4 held by the transportation frame 24 of the apparatus main body 2; a unit 7;

Further, the grounding unit 7 holds a first grounding spring 71 electrically connected to the registration roller 35b, a second grounding spring 72 electrically connected to the grounding member 4, the first grounding spring 71 and the second grounding spring 72, and conveys the apparatus body 2. and a spring holder 73 attached to the frame 24 .

The spring holder 73 has a first holding portion 73a holding the first earth spring 71 and a second holding portion 73b holding the second earth spring 72. The first holding portion 73a holds the first earth spring 71. In addition, in a state where the second earth spring 72 is held by the second holding portion 72b, the first earth spring 71 and the second earth spring 72 are configured to contact each other and conduct.

As described above, in the sheet conveying device 30 according to the present embodiment, the spring holder 73 is provided with the first holding portion 73a that holds the first earth spring 71 and the second holding portion 72b that holds the second earth spring 72. , the first earth spring 71 and the second earth spring 72 can be assembled to the device main body 2 via the spring holder 73 in a state where they are integrally held by the spring holder 73 in advance.

Therefore, the first earth spring 71 and the second earth spring 72, which are the plurality of members provided for grounding the registration roller 35b, can be easily assembled to the apparatus main body 2, and the first earth spring 71 and the second earth spring 72 can be easily assembled. The assembling workability of the earth spring 72 can be improved.

Further, since the first earth spring 71 and the second earth spring 72 are held by the spring holder 73, they come into contact with each other and are electrically connected. The conduction of the first earth spring 71 and the second earth spring 72 can be properly ensured.

Furthermore, as described above, when the first earth spring 71 and the second earth spring 72 are held by the spring holder 73, the conductive state between the first earth spring 71 and the second earth spring 72 is established. The conductive state can be easily confirmed without waiting for assembly to the carrier frame 24 of the main body 2 .

2 Device main body (housing)
4 grounding member 5 image forming unit 7 grounding unit 23a rotary shaft 24 transport frame 30 sheet transport device 35b registration roller (transport roller)
71 first earth spring 72 second earth spring 72a1 first extension 72a2 second extension 72a3 third extension 72a4 fourth extension 73 spring holder 73a first holding portion 73a1 protruding portion 73b second holding portion 73b1 second 1 hooking portion 73b2 2nd hooking portion 73d holder side projecting portion (projecting portion)
73d1 Regulating surface 74 Groove 75 Protruding portion 75a Inclined surface D Outer diameter of the first earth spring H Spacing between the ridges L1 Distance between the third extending portion and the fourth extending portion L2 First extending portion and the second extending portion Distance between extensions S Sheet T1 First direction T2 Second direction

Claims (9)

a housing;
a conveying roller that has a rotating shaft made of metal, is held by the housing via the rotating shaft, and conveys a sheet;
a metal grounding member held in the housing;
a ground unit that connects the conveying roller and the grounding member and grounds the conveying roller to the grounding member;
The ground unit is
a first ground spring electrically connected to the conveying roller;
a second ground spring electrically connected to the ground member;
a spring holder that holds the first ground spring and the second ground spring together and is attached to the housing;
The spring holder is
a first holding portion that holds the first earth spring;
a second holding portion that holds the second earth spring;
In a state in which the first earth spring is held by the first holding portion and the second earth spring is held by the second holding portion,
the first earth spring and the second earth spring are in contact with each other and are electrically connected;
A sheet conveying device characterized by: The first earth spring is a cylindrical compression coil spring,
The first holding part is
A pair of ridges disposed at positions sandwiching the first earth spring in a first direction, which is the radial direction of the first earth spring, and opposed to each other with an interval smaller than the outer diameter of the first earth spring in a natural state. ,
The sheet conveying apparatus according to claim 1, characterized by: The second holding part is
In a second direction orthogonal to the first direction, a first hook and a second hook are arranged at positions sandwiching the first earth spring,
3. The sheet conveying apparatus according to claim 2, characterized by: In the second holding part,
the first hooking portion has a groove into which the second earth spring can be fitted;
The second hooking part has a protrusion that can be hooked with the second earth spring,
4. The sheet conveying device according to claim 3, characterized in that: The projecting portion of the second hooking portion,
having an inclined surface that is inclined in a direction away from the first engaging portion toward the engaging side of the second earth spring and guides the second earth spring when engaging the second earth spring;
5. The sheet conveying device according to claim 4, characterized in that: The second earth spring is
a first extending portion that extends along the first direction and is retained by the first retaining portion; and a second extending portion that is retained by the second retaining portion;
Having a third extension and a fourth extension extending along the second direction,
in the first direction,
the distance between the third extending portion and the fourth extending portion is smaller than the outer diameter of the first earth spring;
in the second direction,
the distance between the first extension and the second extension is greater than the outer diameter of the first earth spring;
The sheet conveying device according to any one of claims 3 to 5, characterized in that: The spring holder is
having a projecting portion that is inserted into the inner diameter portion of the first earth spring and that regulates the position of the first earth spring;
The protrusion is
on both sides in the first direction,
a pair of regulating surfaces that abut against the third extension and the fourth extension of the second earth spring and regulate the position of the second earth spring in the first direction;
7. The sheet conveying apparatus according to claim 6, characterized by: A sheet conveying device according to any one of claims 1 to 7;
an image forming unit that forms an image on a sheet conveyed by the sheet conveying device;
An image forming apparatus comprising: A method for assembling a ground unit provided in the sheet conveying device according to any one of claims 1 to 7 or the image forming apparatus according to claim 8,
a first step of holding the second earth spring in the spring holder by the second holding portion and then holding the first earth spring in the spring holder by the first holding portion to assemble the earth unit;
a second step of assembling the ground unit assembled in the first step to the housing;
A method for assembling a ground unit, characterized by:

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