JP2004238110A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus having a clutch removal preventing and grounding member that allows stable grounding and clutch removal prevention at a low cost without initial investment of a die or the like, is easily attached or detached, and does not come off even by vibration or falling. <P>SOLUTION: The image forming apparatus comprises a torsion spring that has arm units at both ends, has a crank at the end of one arm unit and holds a spring section with a holding tool disposed in a conductive frame structure, an arm fixing tool that is disposed in a part of the frame structure and fixes the end of the other arm unit in the torsion spring, and a hole that is formed in a part of the frame structure and prevents removal of the arm by inserting the crank of the one arm unit. The crank of the one arm unit is inserted into the hole formed in the frame structure while being contacted with a groove formed in a conductive roller shaft to perform the removal prevention and grounding. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, and a multifunction machine using the electrophotographic method, and in particular, a clutch is provided on a roller shaft for recording paper transport 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 in a recording paper conveying roller in an image forming apparatus and prevention of the clutch from being removed by the same member.
[0002]
[Prior art]
In an image forming apparatus such as a copying machine, a printer, a facsimile, and a multifunction machine using the electrophotographic method, a pickup roller for picking up a recording sheet from a sheet feeding cassette, and a sheet feeding section from a manual sheet feeding section. Various rollers are used for conveying the recording paper, such as a manual paper feeding roller, an intermediate roller that relays the recording paper sent by the pickup roller and the manual paper feeding roller, and a registration roller. Since 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, it is necessary to provide a grounding means for releasing the static electricity. Many image forming apparatuses are configured such that a clutch for transmitting and disconnecting a driving force is connected to these transport rollers so that a driving force is applied only when a recording sheet is fed, respectively. If the roller shaft is inserted directly into the transport roller shaft without using a relay gear, it is necessary to prevent the roller shaft from coming off and to insulate the roller shaft by the clutch.
[0003]
Conventionally, one end of a leaf spring made of a sintered alloy or the like is pressed against a conductive roller shaft, and the other end is pressed against a metal frame of a conductive image forming apparatus main body. A method such as pressing is used, and as a means for preventing disengagement of the clutch, an E-ring or a claw for preventing disengagement incorporated in the clutch has been used. However, the grounding means using a leaf spring requires a mold at the time of mass production of the leaf spring, and as the shape of the leaf spring becomes more complicated, the number of processes increases and the unit cost increases. There is a problem that the width is required and the mechanism space is increased.
[0004]
Therefore, for example, in Patent Document 1, a hook for bending one end and hooking it to the end of the roller shaft is pressed at the center with a one-turn portion which is fastened to the image forming apparatus main body, and the other end is pressed against the conductive portion of the image forming apparatus. A configuration is shown in which a linear spring having a compression coil spring portion is tightened, 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 so that the ground can be reliably grounded. Have been. Patent Document 2 discloses a meshing clutch provided on a photosensitive drum, but a plate-like ground plate (42b) and a stopper (CH22) for preventing the slider (CH22) constituting the meshing clutch from coming off. 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
[Problems to be solved by the invention]
However, the configuration disclosed in Patent Document 1 merely uses a linear spring having one winding portion to take the ground, but does not mention anything about retaining the clutch. The configuration shown relates to a grounding member using a leaf spring mentioned as the conventional example and a detachment prevention mechanism provided completely separately from the grounding member, and is complicated, requires many man-hours for assembly, and is expensive.
[0007]
Therefore, in the present invention, it is possible to stably prevent the clutch and the ground from coming off at low cost without making an initial investment such as a mold, and it is also easy to attach / detach and does not come off even by vibration. It is an object 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 conductive roller shaft of a recording paper conveying roller in the image forming apparatus is prevented from coming off and grounding by a retaining / grounding member formed of a torsion spring,
The torsion spring having an arm portion at both ends, a crank at one end of the arm portion, and a spring portion held by a holder provided on a conductive frame structure of the image forming apparatus; and An arm fixing tool provided on a part of the torsion spring to fix an end of another arm part, and an arm stopper provided on a part of the frame structure and inserting a crank of the one arm part 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 arm is prevented from falling off and grounding. Features.
[0009]
As described above, since the clutch having the crank provided on the torsion spring is used to prevent the clutch from coming off and ground, the ground member is a spring, so that there is no need to make an initial investment such as a mold as in a conventional ground member. . In addition, by inserting the crank into the hole provided in the frame structure while the one arm is in contact with the groove provided in the conductive roller shaft, stable grounding and clutch disengagement can be achieved, and It is possible to provide an inexpensive clutch-preventing / grounding member that can be easily attached and detached and does not come off even by vibration.
[0010]
The spring portion of the torsion spring is a contact torsion spring at both ends, and the center portion is sparsely wound, so that the amount of wire used for the spring can be reduced and the material cost can be reduced. There is a problem in that they are entangled with each other and workability is poor during production, but this problem can be solved by forming both ends in close contact winding.
[0011]
Further, the hole provided in the frame structure for receiving 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 / grounding member is also performed. And can be easily removed.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be illustratively 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 to them unless otherwise specified, and are merely mere descriptions. This is just an example.
[0013]
FIG. 1 is a conceptual diagram for explaining the main components of the image forming apparatus according to the present invention and the conveyance path of the recording paper. FIG. 2 is a view from the driving force transmission mechanism side of the image forming apparatus according to the present invention except for the outer cover. FIG. 3 is a side view of the image forming apparatus according to the present invention. FIG. 3 is a view illustrating a state of attachment of the retaining / grounding member in the image forming apparatus of the present invention. FIG. FIG. 5 is a view showing a holder for a spring portion of a retaining / grounding member in the image forming apparatus of the present invention. FIG. 6 is a view showing the retaining / grounding member in the image forming apparatus of the present invention on a roller shaft having conductivity. FIG. 7 is a view showing a set state, and FIG. 7 is a view showing a set state of another embodiment of a retaining / grounding member in the image forming apparatus of the present invention.
[0014]
In the drawing, reference numeral 1 denotes a paper feed cassette containing recording paper 2; 3, a pickup roller for picking up the recording paper 2; 4, a separation roller for separating the picked-up recording paper 2 one by one and sending out the paper; Reference numeral 6 denotes a second paper feed roller for feeding the recording paper placed in the manual paper feed unit one by one. Reference numeral 7 corrects the posture of the received recording paper 2 and adjusts the timing of forming the toner image on the photosensitive member 8. Registration roller 8 for transferring a recording sheet to a transfer position, reference numeral 8 denotes a photosensitive member (image carrier), reference numeral 9 denotes a transfer roller, reference numeral 10 denotes a fixing roller, reference numeral 11 denotes a discharge roller, reference numeral 12 denotes the pickup roller 3, intermediate roller 5, and second supply A motor for sending a driving force to a paper roller 6, a registration roller 7, a photoconductor (image carrier) 8, a fixing roller 10, a discharge roller 11, etc., 13 is a conveyance path of a recording paper from the paper supply cassette 1, and 14 is a manual feed. Paper section 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, a pickup roller 3, an intermediate roller 5, a second sheet supply roller 6, and a registration roller 7 constitute a sheet supply / transport system. Around the photosensitive member 8, a charging device (not shown) An exposure opening, a developing device, a cleaning blade and the like are arranged to constitute a process unit, and a fixing roller 10 and a discharge roller 11 constitute a fixing / discharge system. A transport guide and a transport 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, from the fixing roller 10 to the discharge roller 11. ing.
[0015]
Reference numeral 20 denotes an apparatus main body from which an outer cover of the image forming apparatus is removed, 21 denotes a base frame of the image forming apparatus having a driving force transmission mechanism, and 22 denotes a sheet feeding / transporting system, a process unit, and a fixing unit which transmit the driving force of the motor 12 as described above. A drive plate having a gear train for transmitting to a paper discharge system and the like, made of a conductive metal plate and fixed to a resin frame; 23, a control box of the image forming apparatus; A flapper solenoid that controls a spring clutch 25 that transmits and cuts a driving force to a second paper feed roller 6 for sending paper to the registration roller 7, 26 is an intermediate clutch that controls rotation and stop of the intermediate roller 5, 27 is A registration clutch assembly member (hereinafter simply referred to as a registration clutch) including a registration clutch body for controlling rotation and stop of the registration roller 7 and a clutch holder. A referred to Tokuratchi), 28 the rotation of the pickup roller 3, a paper feed clutch which controls the stop.
[0016]
Reference numerals 30, 31, and 32 denote retaining / grounding members formed of torsion springs, and reference numerals 33, 34, and 35 denote drive plates 22 of conductive metal plates for holding the torsion springs constituting the retaining / grounding member. The spring holders 36, 37, 38 cut and raised in the manner shown in FIG. 5 from FIG. 5 are also used to fix the one-side arms 40, 41, 42 of the torsion springs 30, 31, 32 to prevent rotation. , A fixing tool cut and raised from the drive plate 22, 39 is a conductive shaft of the intermediate clutch 26, 43, 44, 45 are grounding of conductive shafts of the clutches 25, 26, 27, the intermediate clutch 26, An arm for preventing the clutch 28 from coming off, and a drive plate 46 for rotating the arm of the torsion spring 31 by a fixed width around the spring. 2, a fan-shaped hole 2, a crank 47 provided at an end of the arms 44 and 45 in FIG. 4, a base 48 of a spring holder on the drive plate 22 in FIG. 5, and a conductive member 60 in FIG. A groove for contacting the arm of the retaining / grounding member provided on the shaft having a shaft. Reference numeral 70 in FIG. 7 denotes another embodiment of the retaining / grounding member according to the present invention. A torsion spring 71 formed by winding is an arm for preventing the torsion spring of the other embodiment from coming off and grounding, 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 the main components of the image forming apparatus and the transport path of the recording paper. The recording paper accommodated in the paper feed cassette 1 is driven by a motor 12 provided on one surface of a drive plate 22. A pickup roller 3 for picking up the recording paper 2; a separation roller 4 for separating the recording paper 2 one by one and feeding the paper; an intermediate roller 5; a second paper feed roller 6 for feeding the recording paper placed in the manual paper feed unit one by one. The registration roller 7 that corrects the attitude of the recording sheet 2 sent thereto and sends the recording sheet to a transfer position in accordance with the timing of forming a toner image on the photoconductor 8, and is disposed around the photoconductor (image carrier) 8 and the periphery thereof And a process unit including a charging device, an exposure opening, a developing device, and a cleaner (not shown), a fixing roller 10, a discharge roller 11, and the like. Of these, the pickup roller 3, the intermediate roller 5, the second paper supply roller 6, the registration roller 7, the fixing roller 10, and the discharge roller 11 are provided with a paper supply 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), a fixing clutch, a discharge clutch (not shown), and the like. The driving force is transmitted and rotated when necessary.
[0018]
Now, when an image forming instruction is received from a control device (not shown), the photoconductor 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 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. Then, the toner image is sent to the transfer position at the timing when the toner image is formed on the photoconductor 8 by the registration roller 7, and the toner image on the photoconductor 8 is transferred by the transfer roller 9 to which the bias is applied. The recording paper 2 onto which the toner image has been transferred in this manner is sent to a fixing roller 10 to be fixed, and is discharged by a discharge roller 11. That is, when the image forming instruction is received, the pickup roller 3 engages the paper supply clutch 28 to pick up the recording paper 2 stored in the paper supply cassette 1, and the second paper supply roller 6 moves to the manual feed path 14. When the recording paper 2 is placed and the spring clutch 25 is engaged, it rotates and sends the recording paper 2 to the intermediate roller 5. On the other hand, when the recording paper 2 is fed by the pickup roller 3 and the second paper feed roller 6, the intermediate roller 5 is engaged by the intermediate clutch 26 to deliver the recording paper 2 to the registration roller 7, and the registration roller 7 The registration clutch 27 is engaged at the timing when a toner image is formed on the body 8 and the leading end of the toner image comes to the position of the transfer roller 9, and the recording paper 2 is sent to the transfer position.
[0019]
The present invention relates to a roller having conductivity such as a second paper feed roller 6, an intermediate roller 5, and a pickup roller 3, such as a spring clutch, an intermediate clutch, and a paper feed clutch indicated by 25, 26, and 28 in FIG. The grounding of the roller shaft, which is directly attached to the shaft and, as a result, is electrically insulated by inserting the clutch into these conductive roller shafts, and prevents the intermediate clutch 26 and the paper feed clutch 28 from coming off. It is for. Therefore, in the present invention, as shown in FIGS. 3 and 4, the torsion springs 30, 31, and 32 are provided at both ends with arms 40, 41, and 42 for stopping the rotation of the springs, and for providing grounding and retaining. Arms 43, 44, and 45 are provided, and the arms 44 and 45 are provided with a crank 47 (see FIG. 4), as shown by way of example in the case of the torsion spring 31. The crank 47 is inserted into a hole 46 (see FIGS. 3 and 4) provided in the drive plate 22 and the arm is inserted into a groove 60 provided in a roller shaft (conductive shaft) 39, so that grounding and retaining can be performed. It is like that.
[0020]
Then, the holders 33, 34, 35 for holding the springs 30, 31, 32 as ground 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 inside diameter of the spring, and the spring is not 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 when the torsion spring is press-fitted into the base 48 shown in FIG. 5, the press-fitted portion is a part of the coil-wound spring. The spring force of the ground arm 43, 44, 45 can be set as designed. Then, the grounding (earth) is ensured by the light press-fitting of the base 48. Also, 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, 42 have notches for fixing the ends. A groove 60 is provided in the conductive shaft (roller shaft) 39 as shown in FIG. 6 so that the arm does not come off when the arm 44 is hooked.
[0021]
As shown in FIG. 4, the retaining / grounding members 30, 31, 32 constituted by torsion springs are lightly press-fitted into the bases 48 of the spring holders 33, 34, 35 as shown in FIG. As described above, the reliable grounding can be obtained by hanging the notches 41 and 42 on the notches provided in the fixtures 36, 37 and 38. In the case where the number of turns of the spring is small (for example, 2 turns or less), the spring force may be changed by lightly press-fitting the coil-shaped portion, which is not desirable. The other ends of the arms 43, 44, and 45 are brought into contact with 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 part 47 is inserted into the fan-shaped hole 46 provided in the drive plate 22. The arm 45 is also provided with a crank portion, which is inserted into a hole provided in the drive plate 22 similarly to the hole 46, but is omitted in FIG. 3, and the shafts of the spring clutch 25 and the paper feed clutch 28 are omitted. 3 are also omitted in FIG. Hole 46 formed in the fan-shaped, FIG. 3, as shown in FIG. 4, although the width L ₂ is is formed smaller than the length L ₁ of the distal end portion of the crank portion 47 of the arm 44, the arm 44 Is formed in a fan shape so as to be able to rotate a fixed width around the spring, so that it can be easily inserted into the hole 46 by twisting the tip of the arm 44, and once inserted into the hole 46, there is vibration or the like. This also prevents the arm 44 from easily coming off.
[0022]
In the above description, the torsion spring has been described as a tightly wound spring. However, as shown at 70 in FIG. 7, the torsion spring may be wound tightly at both ends and loosely wound at the center. In this way, the material cost of the spring can be reduced, and sparsely wound springs are entangled with each other, resulting in poor workability at the time of production. it can. Further, the arms 40, 41, and 42 which are brought into contact with the conductive shaft 39 are worn by the rotation of the shaft when they are brought into contact with a strong force, and there is a possibility that shavings will be generated and become serious functional defects if they enter the substrate or the like. However, since the tip can be moved freely by the fan-shaped hole 46, it can be applied with a weak load, and such a problem can be avoided. In order to bring the arms 40, 41, 42 into contact with the conductive shaft 39 with a small load, the number of turns of the spring 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 one end of the arm portion, and the spring portion is held by the holder provided on the conductive frame structure of the image forming apparatus. A torsion spring, an arm fixing device provided on a part of the frame structure and fixing an end of another arm portion of the torsion spring, and an arm fixing device provided on a part of the frame structure, A hole for inserting a crank to prevent the arm from coming off. The crank is inserted into a hole provided in a 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, there is no need to make an initial investment such as a mold like a conventional grounding member because the grounding member is a spring. By inserting the crank into the hole provided in the frame structure while making contact with the groove provided in the roller shaft having conductivity, stable grounding and the clutch can be prevented from being disengaged, and it is easy to attach and detach, and vibration However, it is possible to provide an inexpensive clutch grounding member that does not come off and is also used.
[0024]
The spring portion of the torsion spring is a contact torsion spring at both ends, and the center portion is sparsely wound, so that the amount of wire used for the spring can be reduced and the material cost can be reduced. There is a problem in that they are entangled with each other and workability is poor during production, but this problem can be solved by forming both ends in close contact winding.
[0025]
In addition, the hole provided in the frame structure for receiving 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 / 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 recording paper transport path 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, with the outer cover removed, as viewed from the driving force transmission mechanism side.
FIG. 3 is a schematic diagram illustrating a state of attachment of a retaining / grounding member in the image forming apparatus of the present invention.
FIG. 4 is a schematic diagram illustrating a set state of a retaining / grounding member in the image forming apparatus of the present invention.
FIG. 5 is a schematic diagram showing a shape of a holder of a spring portion of the retaining / grounding member in the image forming apparatus of the present invention.
FIG. 6 is a schematic diagram showing a state in which the retaining / grounding member in the image forming apparatus of the present invention is set on a roller shaft having conductivity.
FIG. 7 is a schematic diagram showing a set state of another embodiment of the retaining / 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 Locking / Combined Grounding Members 33, 34, 35 Spring Holders 36, 37, 38 Fixing 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 conductive roller shaft of a recording paper conveying roller in the image forming apparatus is prevented from coming off and grounding by a retaining / grounding member formed of a torsion spring,
The torsion spring having an arm portion at both ends, a crank at one end of the arm portion, and a spring portion held by a holder provided on a conductive frame structure of the image forming apparatus; and An arm fixing tool provided on a part of the torsion spring to fix an end of another arm part, and an arm stopper provided on a part of the frame structure and inserting a crank of the one arm part 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 arm is prevented from falling off and grounding. Characteristic image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the spring portion of the torsion spring is a contact torsion spring at both ends, and a center portion is loosely wound. 3. 2. The image forming apparatus according to claim 1, wherein the hole provided in the frame structure for receiving the crank of the one arm portion is formed in a fan shape along a rotation direction about a torsion spring of the arm. 3. apparatus.

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