JP3973098B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, or a composite machine using an electrophotographic method, and in particular, a clutch is provided on a recording paper conveyance roller shaft to transmit and cut a driving force. The present invention relates to an image forming apparatus configured to perform grounding for releasing static electricity generated on a recording paper conveying roller in the image forming apparatus and preventing the clutch from coming off with the same member.
[0002]
[Prior art]
In an image forming apparatus such as a copying machine, a printer, a facsimile, or a complex machine using an electrophotographic system, a pickup roller for picking up recording paper from a paper feeding cassette, and for feeding paper from a manual paper feeding unit Various rollers are used for conveying the recording paper, such as a manual paper feeding roller, an intermediate roller that relays the recording paper fed by the pickup roller and the manual paper feeding roller, and a registration roller. These transport rollers generate static electricity due to contact with the recording paper and cause problems such as double feeding of the recording paper and adverse effects on the control circuit. Therefore, it is necessary to provide a grounding means for releasing static electricity. In addition, there are many image forming apparatuses configured to connect a driving force transmission and cutting clutch to these conveying rollers so that the driving force is applied only when the recording paper is sent. When it is inserted directly into the transport roller shaft without going through a relay gear, it is necessary to prevent the roller shaft from being detached and the roller shaft is insulated by the clutch. Therefore, it is necessary to provide a grounding means for independently discharging static electricity.
[0003]
Conventionally, as a grounding means for such a conveying roller, one end of a leaf spring using a sintered alloy or the like is pressed against a conductive roller shaft, and the other end is applied to a metal frame of the conductive image forming apparatus main body. A method of pressing is used, and as a clutch disengagement prevention means, an E-ring or a disengagement prevention claw incorporated in the clutch has been used. However, the grounding means using leaf springs requires a mold for mass production of leaf springs. Also, as the shape of the leaf springs becomes more complex, the number of processes increases and the component unit price increases. There was a problem that the space was required and the mechanism space was increased.
[0004]
Therefore, for example, in Patent Document 1, a hook for curving one end and hooking it to the end of the roller shaft, a winding portion for fastening the image forming apparatus main body to the center, and a conductive portion of the image forming apparatus to the other end are pressed. A configuration is shown in which a linear spring having a compression coil spring portion is used, one winding portion is fastened to the image forming apparatus main body, and the hook is pressed against the end of the conductive roller shaft to ensure grounding (grounding). Has been. Patent Document 2 discloses a meshing clutch provided on a photosensitive drum, but a plate-shaped ground plate (42b) and a retaining claw of a slider (CH22) constituting the meshing clutch include a slider. It is shown that it is used for the housing cylinder member (CH23).
[0005]
[Patent Document 1]
Registered Utility Model No. 2579898 [Patent Document 2]
JP-A-6-208322 gazette
[Problems to be solved by the invention]
However, the configuration shown in Patent Document 1 simply uses a linear spring having a single winding portion for grounding, and does not mention anything about retaining the clutch. The configuration shown relates to a grounding member using a leaf spring referred to as the conventional example, and a mechanism for preventing the grounding member from being separated from each other, which is complicated and requires a lot of man-hours for assembly and is expensive.
[0007]
Therefore, in the present invention, without making an initial investment such as a mold, it is possible to stably and stably prevent contact with the ground and the clutch at low cost, and it can be easily detached and cannot be detached even by vibration. An object is to provide an image forming apparatus having a grounding member.
[0008]
[Means for Solving the Problems]
Therefore, in the present invention,
An image forming apparatus in which a clutch inserted into a roller shaft having conductivity of a recording paper conveyance roller in an image forming apparatus is configured to prevent and ground with a retaining and grounding member constituted by a torsion spring,
The torsion spring having arm portions at both ends and having a crank at one end of the arm portion and holding the spring portion with a holding tool provided on the conductive frame structure of the image forming apparatus, and the frame structure An arm fixture that is provided in a part and fixes an end of another arm part in the torsion spring; and a part of the frame structure that is provided in a part of the frame structure, and a crank of the one arm part is inserted to prevent the arm from coming off The crank is inserted into the hole provided in the frame structure while the one arm is in contact with the groove provided in the roller shaft, and the retaining and grounding are performed. Features.
[0009]
As described above, the clutch is prevented from coming off and grounded by the arm having the crank provided on the torsion spring, so that since the grounding member is a spring, it is not necessary to make an initial investment such as a mold like a conventional grounding member. . Further, by placing the crank in the hole provided in the frame structure while bringing the one arm into contact with the groove provided in the conductive roller shaft, stable grounding and prevention of clutch disconnection can be achieved, and An inexpensive clutch retaining and grounding member that can be easily detached and cannot be detached even by vibration can be provided.
[0010]
And, the spring part of the torsion spring is a torsion spring with both ends, and the center part is loosely wound, so that the amount of spring wire used can be reduced and the material cost can be reduced. Although there is a problem that workability is poor at the time of production because they are intertwined with each other, this problem can be cleared by tightly winding both ends.
[0011]
Further, the hole provided in the frame structure for inserting the crank of the one arm portion is formed in a fan shape along the rotation direction around the torsion spring of the arm, so that the setting of the retaining and grounding member is set. And can be easily removed.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. This is just an example.
[0013]
FIG. 1 is a conceptual diagram for explaining main components and a recording paper conveyance path in an image forming apparatus according to the present invention. FIG. 2 is a view from the driving force transmission mechanism side excluding an outer cover of the image forming apparatus according to the present invention. 3 is a side view of the image forming apparatus according to the present invention, and FIG. 4 is a view showing a set state of the grounding member for retaining and retaining in the image forming apparatus of the present invention. FIG. 5 is a view showing a retainer for a spring part of the retaining / grounding member in the image forming apparatus of the present invention, and FIG. 6 is a diagram illustrating a roller shaft having conductivity in the retaining / grounding member of the image forming apparatus of the present invention. FIG. 7 is a view showing a set state, and FIG. 7 is a view showing a set state of another embodiment of the grounding member for retaining and fixing in the image forming apparatus of the present invention.
[0014]
In the figure, 1 is a paper feed cassette containing recording paper 2, 3 is a pickup roller for picking up recording paper 2, 4 is a separation roller for separating the picked recording paper 2 one by one and feeding the paper one by one, and 5 is an intermediate roller , 6 is a second paper feed roller that feeds the recording paper placed in the manual paper feed unit one by one, and 7 is the posture of the recording paper 2 that has been fed and is adjusted to the timing of toner image formation on the photoreceptor 8. A registration roller for feeding the recording paper to the transfer position, 8 is a photosensitive member (image carrier), 9 is a transfer roller, 10 is a fixing roller, 11 is a discharge roller, 12 is a pickup roller 3, intermediate roller 5 and second feed roller. A motor for sending driving force to the paper roller 6, registration roller 7, photoconductor (image carrier) 8, fixing roller 10, discharge roller 11 and the like, 13 is a conveyance path for recording paper from the paper cassette 1, and 14 is manual feed Paper Manual feed conveying path of the recording paper al, 15 is a conveying path from the intermediate roller 5 to the discharge roller 11. Of these, the pickup roller 3, the intermediate roller 5, the second paper feed roller 6, and the registration roller 7 constitute a paper feed / conveyance system. An exposure opening, a developing device, a cleaning blade, and the like are arranged to form a process unit, and a fixing / discharge system is configured by the fixing roller 10, the discharge roller 11, and the like. Further, a conveyance guide and a conveyance roller (not shown) are provided from the paper feed roller 4 to the intermediate roller 5, from the intermediate roller 5 to the registration roller 7, from the photoconductor 8 to the fixing roller 10, and from the fixing roller 10 to the discharge roller 11. ing.
[0015]
20 is a main body of the image forming apparatus with the outer cover removed, 21 is a base frame of the image forming apparatus provided with a driving force transmission mechanism, 22 is a paper feeding / conveying system, process unit, and fixing unit described above. A drive plate having a gear train to be conveyed to a paper discharge system, which is made of a conductive metal plate and fixed to a resin frame, 23 is a control box of the image forming apparatus, and 24 is a recording from the manual feed path 14 A flapper solenoid that controls the spring clutch 25 that transmits and cuts the driving force to the second paper feed roller 6 for feeding the paper to the registration roller 7, 26 is an intermediate clutch that controls the rotation and stop of the intermediate roller 5, and 27 A registration clutch assembly member (hereinafter simply referred to as registration) comprising a registration clutch body and a clutch holder for controlling the rotation and stop of the registration roller 7. A referred to Tokuratchi), 28 the rotation of the pickup roller 3, a paper feed clutch which controls the stop.
[0016]
30, 31, 32 is a retaining / grounding member constituted by a torsion spring, and 33, 34, 35 are drive plates 22 constituted by a conductive metal plate to hold a torsion spring constituting the retaining / grounding member. The spring holders 36, 37, 38 cut and raised in the form as shown in FIG. 5 are also used to fix the one end side arms 40, 41, 42 of the torsion springs 30, 31, 32 to prevent rotation. , A fixture cut and raised from the drive plate 22; 39, a shaft having conductivity of the intermediate clutch 26; 43, 44, 45; grounding of the conductive shaft of each clutch 25, 26, 27; An arm 46 for preventing the clutch 28 from coming off, and a drive plate 46 for rotating the arm of the torsion spring 31 around the spring by a certain width. 2 is a fan-shaped hole, 47 in FIG. 4 is a crank provided at the ends of the arms 44 and 45, 48 in FIG. 5 is a base of a spring retainer on the drive plate 22, and 60 in FIG. In FIG. 7, reference numeral 70 in FIG. 7 is a groove for contacting the arm of the retaining / combination grounding member provided on the shaft having the opposite ends, and both ends are closely wound and the central part is sparse as another embodiment of the present invention. A torsion spring 71 formed by winding, 71 is an arm for preventing and grounding the torsion spring of another embodiment, and 72 is a crank portion of this arm 71.
[0017]
First, an outline of the operation of an embodiment of an image forming apparatus using the present invention will be described with reference to FIG. FIG. 1 is a conceptual diagram for explaining main components and a recording paper conveyance path in an image forming apparatus. Recording paper stored in a paper feeding cassette 1 by a motor 12 provided on one surface of a drive plate 22 is shown. A pickup roller 3 for picking up 2, a separation roller 4 for separating the recording paper 2 one by one and feeding the paper, an intermediate roller 5, and a second paper feeding roller 6 for feeding the recording paper placed in the manual paper feeding section one by one. The registration sheet 7 that corrects the posture of the recording paper 2 that has been fed and sends the recording paper to the transfer position in accordance with the toner image formation timing on the photosensitive member 8, and the photosensitive member (image carrier) 8 are arranged around the periphery. A process unit including a charging device, an exposure opening, a developing device, and a cleaner (not shown), a fixing roller 10, and a discharge roller 11 are driven. Among them, the pickup roller 3, the intermediate roller 5, the second paper feed roller 6, the registration roller 7, the fixing roller 10, and the discharge roller 11 are the paper feed clutch 28 (corresponding to the pickup roller 3) as shown in FIG. An intermediate clutch 26 (corresponding to the intermediate roller 5), a spring clutch 25 (corresponding to the second paper feed roller 6), a registration clutch 27 (corresponding to the registration roller 7), and a fixing clutch and a discharge clutch (not shown) are attached. When necessary, the driving force is transmitted to rotate.
[0018]
Now, when an image formation instruction is received from a control device (not shown), the photosensitive member 8 is exposed by an exposure device (not shown) to form a latent image, and the latent image is developed by a developing device (not shown). Thus, a toner image is formed. On the other hand, the recording paper 2 stored in the paper feed cassette 1 is picked up by the pickup roller 3, sent to the intermediate roller 5 by the paper feed roller 4, and further sent to the registration roller 7. The registration roller 7 sends the toner image to the transfer position in synchronization with the timing at which the toner image is formed on the photoconductor 8, and the toner image on the photoconductor 8 is transferred by the transfer roller 9 to which a bias is applied. The recording paper 2 onto which the toner image has been transferred in this manner is sent to the fixing roller 10 to be fixed, and is discharged by the discharge roller 11. That is, the pickup roller 3 picks up the recording paper 2 contained in the paper feed cassette 1 when the image forming instruction is received, and the second paper feed roller 6 moves to the manual feed path 14. When the recording paper 2 is placed and the spring clutch 25 is engaged, the recording paper 2 is rotated and sent to the intermediate roller 5. On the other hand, the intermediate roller 5 enters the intermediate clutch 26 when the recording paper 2 is fed by the pickup roller 3 and the second paper feeding roller 6, and sends the recording paper 2 to the registration roller 7. The registration roller 7 The registration clutch 27 is engaged at the timing when the toner image is formed on the body 8 and the leading edge of the toner image reaches the position of the transfer roller 9, and the recording paper 2 is sent out to the transfer position.
[0019]
In the present invention, conductive rollers such as the second paper feed roller 6, the intermediate roller 5, and the pickup roller 3, such as the spring clutch, the intermediate clutch, and the paper feed clutch indicated by 25, 26, and 28 in FIG. The roller shaft that is directly attached to the shaft and consequently electrically insulated because the clutch is inserted into these conductive roller shafts, and the intermediate clutch 26 and the paper feed clutch 28 are prevented from coming off. Is for. Therefore, in the present invention, as shown in FIGS. 3 and 4, the torsion springs 30, 31, and 32 are provided with arms 40, 41, and 42 for stopping the rotation of the springs at both ends, and for grounding and retaining. Arms 43, 44, and 45 are provided, and a crank 47 (see FIG. 4) is provided in the arms 44 and 45 as shown in the case of the torsion spring 31 as an example. The crank 47 is placed in the hole 46 (see FIGS. 3 and 4) provided in the drive plate 22 and the arm is placed in the groove 60 provided in the roller shaft (conductive shaft) 39, so that grounding and retaining can be performed. It is what I did.
[0020]
Then, the holders 33, 34, and 35 holding the springs 30, 31, and 32 as the grounding members are cut and raised from the drive plate 22 as shown in FIG. 3, and the base 48 is formed as shown in FIG. It is made slightly smaller than the inner diameter of the spring, and the spring cannot be easily pulled out by lightly press-fitting the spring. In this case, since the number of turns of the torsion spring is sufficiently large as shown in FIG. 3, even if the base 48 shown in FIG. 5 is press-fitted, the press-fitted part is a part of the coil-wound spring. Yes, the spring force of the ground arm portions 43, 44, 45 can be set as designed. And grounding (earthing) is ensured by light press-fitting of the base 48. Further, the arm fixtures 36, 37, 38 for fixing the ends of the arms 40, 41, 42 in the torsion springs 30, 31, 32 are cut and raised from the drive plate 22 as shown in FIG. , 41 and 42 have notches for fixing the ends thereof. Further, as shown in FIG. 6, a groove 60 is provided in the conductive shaft (roller shaft) 39 so that the arm does not come off when the arm 44 is hung.
[0021]
As shown in FIG. 4, the retaining and grounding members 30, 31, 32 constituted by the torsion springs are lightly press-fitted into the base portions 48 of the spring holders 33, 34, 35 as shown in FIG. By applying 41 and 42 to the notches provided in the fixtures 36, 37, and 38, reliable grounding can be obtained as described above. In addition, when the number of turns of the spring is small (for example, 2 or less), the coiled portion is expanded by light press-fitting, and the spring force may change, which is not desirable. Then, the arms 43, 44, 45 at the other end are brought into contact with the grooves 60 provided on the shafts of the spring clutch 25, the intermediate clutch 26, and the paper feed clutch 28 as shown in FIG. The portion 47 is inserted into a fan-shaped hole 46 provided in the drive plate 22. The arm 45 is similarly provided with a crank portion and is inserted into a hole provided in the drive plate 22 like the hole 46, but is omitted in FIG. 3, and the shafts of the spring clutch 25 and the paper feed clutch 28 are also omitted. Is also omitted in FIG. As shown in FIGS. 3 and 4, the fan-shaped hole 46 has a width L ₂ that is smaller than the length L ₁ of the tip of the crank portion 47 of the arm 44. Is formed in a fan shape so that it can rotate with a constant width around the spring, so that it can be easily inserted into the hole 46 by twisting the tip of the arm 44. As a result, the arm 44 cannot be easily removed.
[0022]
In the above description, the torsion spring has been described as a tightly wound spring. However, as shown by 70 in FIG. 7, both ends may be closely wound and the central portion may be loosely wound. In this way, the material cost of the spring can be reduced, and sparsely wound springs are intertwined with each other, resulting in poor workability during production. it can. Further, the arms 40, 41, 42 to be brought into contact with the conductive shaft 39 are worn by the rotation of the shaft when brought into contact with a strong force, and if a scrap is generated and enters a substrate or the like, a serious functional defect may occur. However, since the tip can be freely moved by the fan-shaped hole 46, it can be applied with a weak load, and such a problem can be avoided. In addition, since the arms 40, 41, and 42 are brought into contact with the conductive shaft 39 with a weak load, the number of springs may be increased.
[0023]
【The invention's effect】
As described above, according to the present invention, the arm portion is provided at both ends, the crank is provided at the end of one arm portion, and the spring portion is held by the holder provided in the conductive frame structure of the image forming apparatus. A torsion spring, an arm fixture provided at a part of the frame structure, for fixing an end of another arm part of the torsion spring, and provided at a part of the frame structure; The crank is inserted into a hole provided in the frame structure while the one arm is in contact with a groove provided in the conductive roller shaft. Since the grounding member is a spring, it is not necessary to make an initial investment such as a mold as in the case of a conventional grounding member. By inserting the crank into the hole provided in the frame structure while making contact with the groove provided on the conductive roller shaft, stable grounding and clutch disconnection can be prevented, and attachment / detachment is easy and vibrations, etc. However, an inexpensive clutch retaining and grounding member that does not come off can be provided.
[0024]
And, the spring part of the torsion spring is a torsion spring with both ends, and the center part is loosely wound, so that the amount of spring wire used can be reduced and the material cost can be reduced. Although there is a problem that workability is poor at the time of production because they are intertwined with each other, this problem can be cleared by tightly winding both ends.
[0025]
In addition, the hole provided in the frame structure for inserting the crank of the one arm portion is formed in a fan shape along the rotation direction around the torsion spring of the arm, so that the setting of the retaining and grounding member can be performed. Removal can be performed easily.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram for explaining main components and a conveyance path of a recording sheet in an image forming apparatus according to the present invention.
FIG. 2 is a side view of the image forming apparatus according to the present invention as viewed from the driving force transmission mechanism side excluding the outer cover.
FIG. 3 is a schematic view showing a state of attachment of a retaining and grounding member in the image forming apparatus of the present invention.
FIG. 4 is a schematic view showing a set state of a retaining and grounding member in the image forming apparatus of the present invention.
FIG. 5 is a schematic view showing the shape of a holder of a spring portion of a grounding member for retaining and retaining in the image forming apparatus of the present invention.
FIG. 6 is a schematic view showing a state in which a retaining and grounding member in the image forming apparatus of the present invention is set on a conductive roller shaft.
FIG. 7 is a schematic view showing a set state of another embodiment of the retaining and grounding member in the image forming apparatus of the present invention.
[Explanation of symbols]
22 Drive plate 24 Flapper solenoid 25 Spring clutch 26 Intermediate clutch 27 Registration clutch 28 Feed clutch 30, 31, 32 Retaining and grounding members 33, 34, 35 Spring holders 36, 37, 38 Fixing tool 39 Conductive shaft 40, 41, 42 One end side arm 43, 44, 45 Arm 46 hole

Claims (3)

An image forming apparatus in which a clutch inserted into a roller shaft having conductivity of a recording paper conveyance roller in an image forming apparatus is configured to prevent and ground with a retaining and grounding member constituted by a torsion spring,
The torsion spring having arm portions at both ends and having a crank at one end of the arm portion and holding the spring portion with a holding tool provided on the conductive frame structure of the image forming apparatus, and the frame structure An arm fixture that is provided in a part and fixes an end of another arm part in the torsion spring; and a part of the frame structure that is provided in a part of the frame structure, and a crank of the one arm part is inserted to prevent the arm from coming off The crank is inserted into the hole provided in the frame structure while the one arm is in contact with the groove provided in the roller shaft, and the retaining and grounding are performed. An image forming apparatus. The image forming apparatus according to claim 1, wherein the spring portion of the torsion spring is a close-contact torsion spring at both ends, and the central portion is loosely wound. 2. The image forming apparatus according to claim 1, wherein the hole provided in the frame structure in which the crank of the one arm portion is inserted is formed in a fan shape along a rotation direction around a torsion spring of the arm. apparatus.

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