JP2004117394A - Driving releasing device for image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving releasing device for an image forming apparatus equipped with a driving device capable of using a single main motor installed previously as it is by easy control without causing cost rising. <P>SOLUTION: The driving releasing device is attached to the image forming apparatus 1, and a driving switching means has a rocking member 18 pivotally supported in an image forming apparatus main body 10A and a spring 20 energizing the transmission gear 17 of a gear end 18A in a direction where it is separated from the gear 6A1 on a fixing means 6A side, and the gear 17 is maintained at a regular position P1 where it is driven with the gear 6A1 by making an interlocking operation member 19 push in an elastic operation end 20B and canceling a state where the elastic force of the spring 20 is exerted on an operation end 18B when a door is closed, and the gear 17 is transited to posture at a releasing position P2 where it is separated from the gear 6A1 by making the member 19 cancel the push-in of the end 20B when the door is opened. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a driving release device provided in a fixing device in an image forming apparatus, and more particularly to a driving device in an image forming device in which related components of a driving force transmission unit provided in the fixing device are switched between driving release and connection. It relates to a release device.
[0002]
[Prior art]
2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a printing machine, a developed toner image transferred from a photoconductor serving as a latent image carrier is prevented from peeling off from a transfer medium such as recording paper. For this purpose, a fixing step is performed.
As one of the configurations used in the fixing process, there is a configuration in which a fixing roller having a built-in heat source and a pressure roller provided opposite thereto are combined.
[0003]
On the other hand, in the image forming apparatus provided with the fixing device having the above-described configuration, a conveying path for the recording paper fed from the paper feeding unit to reach the fixing device by the sheet conveying means is provided in a vertical direction, and the conveying path is provided. Some image forming apparatuses have a configuration in which a part of a wall surface of a housing is formed with an opening / closing lid at a portion facing a conveyance path or a fixing device, thereby opening the conveyance path.
[0004]
In the above configuration, when a part of the wall is opened, most of the transport path can be visually recognized from the outside, and the transport path can be shortened because the transport path is substantially integrated at one place. There is an advantage that the transfer time can be shortened accordingly. When a paper jam occurs in the conveyance path or the fixing device having the above-described configuration, that is, when a so-called jam occurs, a part of the wall portion is formed by an opening / closing lid, so that when the opening / closing lid is opened, the recording paper can be easily taken out. become.
[0005]
When a jam occurs in the fixing device having the above configuration, when a part of the recording paper is pinched between the rollers of the fixing device when the recording paper is taken out, the roller is rotated in a direction in which the recording paper can be fed out. Since the roller is engaged with a gear which is a drive transmission member on the image forming apparatus main body side, pulling out the recording paper is affected by the rotational torque of the gears having the meshing relationship, and cannot be easily taken out. There are cases.
Conventionally, a configuration in which the engagement of gears used for a driving force transmission device between a fixing device and an image forming device is released to allow the recording paper to be taken out without being affected by the rotation torque described above, for example, "JP-A-2000-321915" (
It is disclosed in Patent Document 1.
[0006]
In Patent Document 1, there is disclosed a lever that swings by a projection provided on a part of a housing wall portion, and a slide that is pushed and pulled by one of the swing ends of the lever by swinging the lever. By providing a possible link and a bracket to which one of the swing ends is attached to one end of the link, and supporting the fixing device side gear at the other of the swing ends of the bracket, a part of the housing wall portion is formed. When the lever is released, the link moves to swing the bracket by the swing of the lever, and the gear on the fixing device side is separated from the gear on the image forming device side.
[0007]
[Patent Document 1]
JP 2000-321915 A
[0008]
[Problems to be solved by the invention]
However, in the configuration disclosed in Patent Literature 1, a configuration in which the gears on the fixing device side and the image forming device side are disengaged and engaged with each other is incorporated into the image forming device together with the fixing roller. For this reason, even when the fixing roller is replaced, the fixing roller must be removed from the image forming apparatus together with the mechanism that meshes with the gears and releases the coupling, which not only makes the disassembling and attaching work troublesome, but also requires only the fixing roller. Cannot be replaced, the cost of replacement parts increases.
[0009]
The mechanism that releases the meshing connection between the gears is a combination of a lever and a link that moves on the lever.However, since the operating directions of the lever and the link are a horizontal direction and a vertical direction perpendicular to each other, particularly, the fixing is performed. The space occupied in the horizontal direction parallel to the axial direction of the roller increases. For this reason, the length in the longitudinal direction of the fixing device parallel to the axial direction of the fixing roller becomes longer, and it becomes difficult to reduce the size of the image forming apparatus incorporating this device.
By the way, as shown in FIG. 7, there is an engagement disengagement mechanism between the gear 100 on the fixing roller side and the gear 120 on the swing end of the lever 110. Here, the lever 110 has a configuration in which a gear 120 is pivotally attached to one swinging end, and a link 130 that slides according to opening and closing of the door 140 is brought into contact with the other swinging end.
[0010]
In this case, the swing end gear 120 is urged in the disengagement direction by the torsion spring 150, and the link 130, which is interlocked with the door end when the door is closed, is slid by the projection 160 on the door side. 120 is pushed to the meshing position (solid line position), and even when the door is closed, the solenoid 170 is driven to forcibly swing the lever 110 to the release position (the position indicated by the two-dot chain line), and the swing end gear 120 is moved. The mesh release operation is being performed.
In addition, absorption of variations in the position of the tip of the projection 160 on the door side and absorption of impact when the tooth tip of the swing end gear 120 and the gear 100 of the fixing roller collide with each other when the door is closed are absorbed. In consideration of the above, a sliding body 180 is provided at the end facing the projection 160 on the door side so as to be protruded and urged by the compression spring 190 and pressed against the tip of the projection 160 on the door side.
[0011]
In the case of adopting such a configuration, the tolerance of the pressure of the torsion spring 150 (normally, 20%) is anticipated, and if the tolerance of the compression spring 190 (normally, 10%) is expected, the load sucked by the solenoid 170 is accordingly increased. As a result, the size of the solenoid 170 is increased, the mass is increased, and the power consumption is increased. In addition, the load on the door due to the stress of the compression spring 190 increases the deformation with time.
[0012]
SUMMARY OF THE INVENTION The present invention has been made based on the above-described problems, and has been made in consideration of a drive in an image forming apparatus having a drive device capable of directly using a single main motor provided in advance by simple control without increasing costs. An object of the present invention is to provide a release device. It is still another object of the present invention to provide a drive release device in an image forming apparatus capable of improving the workability, exchangeability, and operation stability by assembling a function of switching related components of the drive release device. Furthermore, by reducing the load of the spring stretched in the image forming apparatus, the assemblability / operability is facilitated, and the load on the housing (structure) of the device is prevented from being deformed over time. It is an object of the present invention to provide a driving release device in an image forming apparatus that can perform the driving.
[0013]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a sheet conveying means for conveying a sheet, a fixing means for fixing a toner image transferred to the sheet, and a drive for switching a driving force transmitting portion for driving the fixing means between a driving force release state and a connection state. Switching means, and a door capable of opening and closing a part of the image forming apparatus main body wall for performing jam processing when a sheet conveyance failure occurs. An interlocking operation member for setting the drive switching means to a release state when the door is opened in the connected state, wherein the drive switching means has an operation end provided to the interlocking operation member and A swinging member that includes a gear end that supports a transmission gear of the driving force transmission unit and is pivotally supported through a fulcrum shaft in the image forming apparatus main body; and an elastic operation end that presses an operation end of the swinging member. Gear transmission A spring that urges the gear in a direction to be disengaged from the gear on the fixing unit side, and when the door is closed, the interlocking operation member pushes the elastic operation end of the spring to a predetermined position, By reducing or eliminating the state in which the elastic force is applied to the operating end of the oscillating member, the transmission gear at the gear-facing end of the oscillating member is maintained in a normal posture in which the transmission gear is drivingly connected to the gear on the fixing unit side. When the door is opened, the interlocking operation member reduces or eliminates the pushing of the elastic operation end of the spring, so that the transmission gear at the gear end of the oscillating member shifts to the drive release position in which the transmission gear is disengaged from the fixing unit side gear. It is characterized by making it.
[0014]
As described above, in the drive release device in the image forming apparatus including the drive device that can use the single main motor as it is, when the door is closed, the interlocking operation member that slides in conjunction with the door is displaced by the elastic operation end of the spring. And the transmission gear of the oscillating member can be maintained in the normal position for driving connection with the gear on the fixing means side, and the interlocking operation member that slides in conjunction with the door when the door is open reduces the pushing of the elastic operation end of the spring. Alternatively, the transmission gear of the swinging member can be switched to and maintained in the drive release position in which the transmission gear of the swinging member is disengaged from the gear on the fixing means side in conjunction with the disappearance, and the switching function of the related parts of the drive release device can be assembled, workability and exchangeability can be improved. The operation stability can be improved.
Therefore, when the door is opened, the interlocking operation member that slides in conjunction with the door reduces or eliminates the pushing of the elastic operation end of the spring, so that the elastic operation end of the spring presses the operation end of the swing member. The transmission gear of the swinging member can be released from the normal posture and switched to the driving release posture, so when a jam occurs, the driving force transmission to the fixing roller should be released by operating only the interlocking operation member that works with the door. Becomes possible. Furthermore, the operating ends of the interlocking operation member and the swinging member are maintained in a state where they are not directly pressed, and the elastic operation end of the spring is interlockingly displaced in a pressing state only with the interlocking operation member, thereby comparing the elastic force of the spring itself. At this point, deformation over time can be prevented by reducing the load on the door on the image forming apparatus main body side. In addition, the spring can absorb the displacement of the door and the interlocking operation member, and does not require a separate spring for absorbing the displacement of the door.
[0015]
According to a second aspect of the present invention, in the drive canceling device of the image forming apparatus according to the first aspect, the swing member is urged by an elastic force in a direction opposite to a swing direction of the spring around the fulcrum axis. A second spring is stretched, and an elastic force of the second spring about the fulcrum axis is set to be weaker than an elastic force of the spring about the fulcrum axis.
Thus, regardless of the posture of the swing member and the transmission gear, when the pressing force of the spring does not work, the second spring switches the swing member to the normal posture, and causes the transmission gear to interlock with the gear on the fixing unit side. Therefore, the driving of the fixing unit can be reliably performed, and the degree of freedom of the layout of the second spring and the swing member is increased.
[0016]
According to a third aspect of the present invention, in the drive release device of the image forming apparatus according to the first aspect, the swing member is forcibly moved from the normal posture to the posture of the drive release when the door is opened when the door is closed. A forcible driving means for causing the image forming apparatus main body to oscillate, and forcibly driving the forced driving means for a predetermined time immediately after the image forming apparatus main body is turned on or after the door is closed.
As described above, even when other units such as the photosensitive drum and the developing roller of the image forming apparatus are being driven for pre-rotation in the door closed state, the forcible driving unit is turned on for a predetermined time, so that the swing member is turned on. Switching, the transmission gear of the oscillating member can be disengaged from the normal posture and switched to the posture for releasing the drive, so that the fixing roller is kept stopped, and the pressure is applied immediately after the power is turned on or for a predetermined time after the door is closed. The escape of heat to the rollers can be minimized, the time required for startup is reduced, and the first print time can be shortened.
[0017]
According to a fourth aspect of the present invention, in the drive canceling device of the image forming apparatus according to the first aspect, the forcible driving means is a member (solenoid) driven by an electric signal, and the drive switching means together with the swing member. Is mounted on the drive unit housing.
As described above, the member (solenoid) driven by an electric signal, which is the forcible driving means, is attached to the drive unit housing of the drive switching means together with the swinging member, so that the operability at the time of assembly replacement can be facilitated.
[0018]
According to a fifth aspect of the present invention, there is provided the image forming apparatus according to the third aspect, further comprising means for detecting an internal temperature or a fixing roller temperature of the image forming apparatus, wherein the roller is provided when the door is closed or the power is turned on. It is characterized in that a determination is made as to whether or not to perform the drive release operation according to the temperature.
As described above, since the determination as to whether or not to perform the drive release operation is made based on the roller temperature, the release operation is omitted, for example, when the roller temperature is close to the feasible fixing temperature. If the internal temperature is close to the predetermined temperature, the release operation is omitted. If the temperature is lower than the guaranteed use temperature of the product, the release operation is omitted. Such control can be performed as needed, and the power for turning on the solenoid can be reduced, and the effect of preventing the movable section from deteriorating can be obtained.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a schematic diagram of an image forming apparatus provided with a drive release device in the image forming apparatus as an embodiment of the present invention. The image forming apparatus shown in FIG. 1 is a printer capable of forming an electrostatic latent image corresponding to an image on a photoconductor by optically writing the image information.
In FIG. 1, a printer 1 includes a drum-shaped photoreceptor 2, and a charging device (not shown) for performing an image forming process during the rotation of the photoreceptor 2; 3, a developing device (not shown), a transfer device 4, and a cleaning device (not shown) are arranged. The recording paper is fed to the transfer device 4 from the paper feeding device 5 to the transport path S1, and the visible image is transferred by the toner carried on the photoreceptor 2, and the transferred recording paper is fixed. After the image is fixed by the device 6, the image is discharged toward the paper output tray 7.
[0020]
In the printer 1 shown in FIG. 1, a transport path S1 of a recording sheet fed from a sheet feeding device 5 as a sheet transport unit is extended in a vertical direction, and a part of a housing wall portion of a printer body facing the transport path S1. Is provided with a cover 1A which is a lid having a rectangular long plate shape that can be opened and closed, and an opening and closing portion is formed. The cover 1A has a lower end hingedly connected to a front end of the apparatus main body by a hinge portion h, and a handle portion (not shown) is formed at an upper end portion. A magnet catch (not shown) that can be held is provided, and a pressing piece 1A1 (see FIG. 4B) described later protrudes from a rear side surface near the upper end.
[0021]
Therefore, if a jam occurs in the transport path S1, most of the transport path can be exposed to the outside by opening the cover 1A. In addition, since the length of the transport path can be shortened by using the transport path S1 as compared with the case where the transport path S1 is configured to be detoured inside the printer 1, the transport time is reduced, and the printout process is performed at high speed. Can be
The fixing device 6, which is located near the end of the recording paper transport path, includes a fixing roller 6A and a pressure roller 6B which are in contact with each other across the recording paper transport path S1, and are provided on the image bearing surface of the recording paper. Are facing each other. In the fixing device 6, a heat fixing process of an unfixed image can be performed while nipping and conveying the recording paper between the fixing roller 6A and the pressing roller 6B.
[0022]
The fixing device 6 shown in FIG. 1 is provided with a fixing roller 6A and a driving force transmitting unit (mechanism unit) for transmitting a driving force to the fixing roller 6A. As shown in the drawing, the driving force transmission unit (hereinafter simply referred to as a transmission unit) 10 is unitized and configured.
In the fixing device 6, when a part of the recording paper is pinched between the rollers when a jam occurs in the conveyance path S1, the transmission of the driving force to the fixing roller 6A is released. The drive release device 30 having the function is provided to face the transmission unit 10.
[0023]
FIG. 2 is a diagram of the transmission unit 10 as viewed from the side where the fixing roller 6A is mounted. Therefore, the fixing roller 6A is attached to the near side with respect to the paper surface. Incidentally, FIG. 2 is a side view of the transmission unit 10 constituting the driving force transmission unit, and the direction of the blindness in FIG.
[0024]
In FIG. 2, the transmission unit 10 forms a part of the main body frame 1B, includes a peripheral wall 10A of the transmission unit main body, and has a box-shaped structure in which one surface in a rising direction of the peripheral wall 10A is opened. As shown in FIG. 4A, the fixing roller 6A is separately attached to a main body frame 1B which forms a base frame of the apparatus main body of the printer 1. On a side surface of the transmission unit 10 forming a driving force transmission unit, a main motor (not shown) serving as a rotational drive source in the printer 1 that collectively drives the developing roller in the developing device 6 and the like including the fixing roller 6A described above. The main motor housing 11 is screwed and provided, and an output shaft (not shown) of the main motor projects from a part of the side surface into the internal space of the transmission unit 10.
[0025]
As shown in FIG. 2, a main motor gear 12 is attached to the output shaft of the main motor, and one of the intermediate transmission gears 13 meshes with the main motor gear 12.
The rotation of the intermediate transmission gear 13 is transmitted to a plurality of intermediate gears 14, 15, 16 set in consideration of the reduction ratio and the like. Reference numeral 16 denotes an idle gear which is the final stage of the intermediate gear and has a driven small idle gear 16A. The small idle gear 16A meshes with a transmission gear 17 that can mesh with a fixing gear 6A1 (see FIG. 5) supported coaxially with the fixing roller 6A, and transmits rotation. FIG. 3 is a rear view of the transmission unit 10 shown in FIG. 2 (in FIG. 4A, an arrow view in a direction indicated by a reference sign d2). The driving release device 30 releases the transmission of the driving force to the fixing roller 6A.
[0026]
As shown in FIGS. 2 and 4A, the driven gear 17 is attached to a swing end 18A of a swing member 18 using an auxiliary frame 18F.
The swing member 18 is swingably supported by using a support shaft 16B of the idle gear 16A as a swing fulcrum. Accordingly, the transmission gear 17 is forcibly released from meshing with the normal position P1 (see FIG. 4B) in a normal state in which the transmission gear 17 meshes with the fixing gear 6A1 according to the swing position of the swing member 18. One of a forced release state (forced release position) P3 (see FIG. 5) and a release position P2 (see FIG. 6) in which the engagement is released when the front cover 1A is opened is selected. The positions in these states are respectively set by switching the direction in which the drive release device 30 described later swings in conjunction with the sliding of the interlocking operation member 19.
[0027]
Here, the drive switching means, which is a main part of the drive release device 30, includes a swing member 18 pivotally supported on a main frame 1B, which is a main body frame in the main body of the apparatus, via a support shaft 16B, which is a fulcrum shaft. A spring 20 having an elastic operation end 20B for pressing the operation end 18B of the moving member 18 is formed.
The swing member 18, which is a part of the drive switching means, is bent from an elongated main body 183, left and right extending portions 181 and 182 extending from right and left ends thereof, and an intermediate portion between the left extending portion 181. An intermediate extension 184 is formed. The left and right extending portions 181 and 182 are penetrated through the support shaft 16B so as to be relatively displaceable, and are pivotally supported.
[0028]
As shown in FIG. 4 (a), of the two extending portions of the swinging member 18, the extending portion 181 on the upper side of the drawing forms a swinging end 18B by a portion whose tip end extends above the support shaft 16B. I do. Further, the extension 182 on the lower side of the drawing forms a gear end 18A that supports the transmission gear 17 by a portion below the support shaft 16B and the auxiliary piece 18F.
The support shaft 16B has the small idle gear 16A externally fitted thereto, and the transmission gear 17 at the gear end 18A is also externally fitted to the support shaft 16B, so that the small idle gear 16A and the transmission gear 17 are relatively engaged with each other. Swing displacement.
[0029]
The intermediate extension portion 184 is fitted so as not to interfere with the elongated hole 27 provided on the main body frame 1B side, and a penetrating extension end is formed as a hook portion 18E capable of locking a locking pin 24 of a solenoid 24 described later. In addition, a part of the spring locking portion 18 </ b> F is locked to one end of the second spring 23.
The other end of the second spring 23 is locked by a hook 32 provided on the side of the main body frame 1B, so that the swing member 18 is turned around the support shaft 16B toward a normal position P1, which is a normal posture. Is formed. The elastic force of the second spring 23 is set to be smaller than the elastic force of the spring 20, and when the elastic force of the spring 20 works effectively, the elastic force of the spring 20 resists the elastic force of the second spring 23. The swing member 18 is formed to be rotatable toward the release position P2.
[0030]
The spring 20 which is a part of the drive switching means is a torsion spring. When the elastic operation end 20B of the spring 20 comes into contact with and presses the operation end 18B of the swing member 18, the transmission gear 17 of the gear end 18A is fixed to the fixing means side. Of the fixing gear 6A1.
Here, in FIG. 4 (a), the support shaft 16B is penetrated and mounted on two body frames 1B opposed to each other, and one end of the support shaft 16B extends toward the outside of the machine (upper side), and the same extension end is provided. The coil portion of the spring 20, which is a torsion spring, is externally fitted and supported. One protruding end of the spring 20 is engaged with the locking portion k (see FIG. 3) on the main body frame 1B side, and the other protruding end, the elastic operation end 20B, interferes with the elongated hole 21 provided in the main body frame 1B. The extension end that is inserted and penetrated so as not to engage with the pressing end 19C of the interlocking operation member 19 and the operation end 18B of the swinging member 18 is formed.
[0031]
As shown in FIGS. 4A and 4B, the interlocking operation member 19, which is a main part of the drive release device 30, is provided so as to be interlockable with the cover 1A as a door. The interlocking operation member 19 has a long plate shape, a long groove 19A2 and a long hole 19A1 are formed in the center, a pressing end 19C is formed at one end, and a door end 19A is formed at the other end.
[0032]
The interlocking operation member 19 has the long groove 19A2 and the long hole 19A1 non-removably fitted into a pair of sliding contact pins 19B protruding from the pressing body frame 1B, thereby supporting the sliding operation in the operation direction X (see FIG. 4). Have been. The pressing end 19C is arranged so as to face the operating end 18B but not in a pressing relationship with each other. The door end 19A is provided to face the pressing piece 1A1 protruding from the inner wall of the cover 1A, which is a door. Here, in the disclosure of the cover 1A, the interlocking operation member 19 is located at the reference position Q1 with the pressing end 19C receiving the pressing force of the spring 20, and is pressed by the pressing piece 1A1 when the cover 1A is closed, and is positioned at the pressing position Q2. Switch to When the interlocking operation member 19 is located at the reference position Q1, the distance between the center position L0 of the fixing roller 6A and the door end 19A is set to B, and when the interlocking operation member 19 is located at the pressing position Q2, the fixing roller 6A Is set to A between the center position L0 and the door end 19A. That is, when the cover 1A reaches the closed position from the open position, the interlocking operation member 19 is displaced from the reference position Q1 to the pressing position Q2 by the pressing piece 1A1, and the interlocking operation member 19 is displaced by a distance different by (BA). Will slide.
[0033]
Such an interlocking operation member 19 is located at the pressing position Q2 when the cover 1A is closed, and switches the swinging member 18 which is a part of the drive switching means to the connected state (connection position P1). Upon receiving the pressing force of 20, the operation is switched to the release state (release position P2, forced release position P3).
As shown in FIG. 4 (a), when it is possible to oscillate masculinely by opposing the elastic operation end 20B of the spring 20 which is a torsion spring (see FIG. 6 described later), A solenoid 24 is provided.
[0034]
A solenoid 24, which is a forcible driving means, is provided facing the hook portion 18E of the intermediate extension portion 184 of the swing member 18. The solenoid 24 is fastened and fixed to a bracket 25 attached to the main body frame 1B of the transmission unit 10, and engages a locking pin 24A1 formed on an actuator 24A serving as an operating portion with a hook portion of the intermediate extension portion 184. 18E so that it can be locked.
The solenoid 24 is energized at the time of operation. At the time of operation, the actuator 24A is drawn into the solenoid main body. At that time, the movement stroke of the actuator 24A is determined by moving the swing member 18 in FIG. ) Is set to an amount suitable for switching from the normal position P1 shown in FIG. 5) to the forced release position P3 shown in FIG. The movement stroke of the actuator 24A is defined by a flange 24B fixed to the actuator 24A.
[0035]
In forcibly switching and moving such a swinging member 18 to the forced release position P3, the swinging member 18 here comes into contact with the elastic operating end 20B of the spring 20 against its operating end 18B, and the intermediate extension portion 184. One end of the second spring 23 is locked to the spring locking portion 18F. Moreover, in this state, the operating end 18B of the swinging member 18 and the pressing end 19C of the interlocking operating member 19 do not have a pressing relationship, and are merely opposed to the elastic force of the second spring 23 having a low spring constant. What is necessary is just to rotate 18 around the support shaft 16B which is a fulcrum shaft.
[0036]
In this manner, the meshing connection between the transmission gear 17 of the swing member 18 and the gear 6A1 on the fixing device side is released by using the elastic force of the spring 20 or the like. A solenoid 24 interlocked with the projecting portion 184 and the hook portion 18E, and the solenoid 24 operates in the direction of movement through the intermediate extending portion 184 and the swing member 18 and the direction of action of the elastic force of the spring 20 and the second spring 23. In the horizontal and vertical directions perpendicular to each other, the swing connection of the transmission gear 17 is performed by the swing of the swing member 18, and the degree of freedom of the layout of the swing member 18 and both springs is increased.
[0037]
Further, a small solenoid (for example, about 3N) having a relatively small capacity can be employed without increasing the exciting force of the solenoid 24, that is, the capacity, without increasing the capacity. There is an advantage that means for suppressing the solenoid suction force can be adopted.
The operation timing of the solenoid 24 corresponds to the start of the printer 1, which corresponds to the start of the main motor, and is determined immediately after the start of the main motor or after the cover 1A changes from the open state to the closed state. In addition to the setting during the time, the ambient temperature in the printer at the time of warm-up or the surface temperature of the fixing roller 6A is required.
[0038]
In this embodiment, a temperature sensor (not shown) capable of detecting the temperature inside the printer and the surface temperature of the fixing roller 6A is provided, and the output of the temperature sensor is used as a drive control unit (not shown) for the solenoid 24. To be output. When the ambient temperature in the printer 1 and the surface temperature of the fixing roller 6A are set as conditions, the surface temperature of the fixing roller 6A is a predetermined temperature, in this case, a temperature close to a temperature at which fixing can be performed, or the ambient temperature in the printer 1 Are set so that the solenoid 24 is not operated when the ambient temperature is close to the ambient temperature during a normal printing operation or when the temperature is lower than the guaranteed use temperature of the printer. These conditions are different from those at the time when the temperature of the fixing roller 6A is raised, in that the temperature gradient when the fixing roller 6A comes into contact with the pressure roller 6B tends to be less likely to occur or when the temperature gradient is quickly eliminated. The power consumption of the solenoid 24 is reduced without interrupting the transmission of the driving force to the roller 6A.
[0039]
In this embodiment, the cover 1 is in the closed position independently of the open / closed state of the cover 1A by setting the operating position of the solenoid 24 as the driving means in the above-described configuration based on the above-described conditions. Sometimes, the meshing relationship between the transmission gear 17 and the fixing gear 6A1 can be changed.
At this time, the elastic operation end 20B of the spring 20 is locked with the pressing end 19C of the interlocking operation member 19, but is not locked with the operation end 18B of the swinging member 18.
That is, since the operating end 18B of the swing member 18 has a gap between the elastic operating end 20B of the spring 20 and the distance C, the counterclockwise force Pa by the second spring 23, which is a tension spring, is applied. There is only one.
[0040]
On the other hand, the elastic force Fa of the spring 20 (the moment around the support shaft 16B, which is a fulcrum shaft) is balanced with the pushing force Wa of the pressing piece 1A1 via the interlocking operation member 19.
When the power is turned on again after the power is turned off in this state, a predetermined voltage is applied to the solenoid 24, and the actuator 24A, which has fallen downward by the force of its own weight G, moves upward by the suction force Na. Here, the moment about the support shaft 16B of the swing member 18 due to the suction force Na is naturally set to be larger than the sum of the moment due to the own weight G and the tensile force Pa of the second spring 23.
[0041]
When the actuator 24A moves upward, the hook portion 18E of the intermediate extension portion 184 locked with the locking pin 24A1 driven into the actuator 24A turns clockwise, that is, the forced release position P2 (see FIG. 5). Start spinning towards. The actuator 24A is placed below the main body of the solenoid 24 until the actuator 24A is sucked. However, if the distance therebetween is larger than a predetermined amount, a sufficient suction force cannot be obtained. Therefore, the main body frame 1B on which the main body of the solenoid 24 is mounted is provided with a projection 35 supported by W to control the amount of fall of the actuator 24A. That is, the projection 35 is positioned where the retaining ring 24B provided integrally with the actuator 24A moves (falls) by about 5 mm as compared with the case of the forced release position P3 shown in FIG.
[0042]
Next, when the solenoid 24 is driven, the actuator 24A moves upward as shown in FIG.
In this case, suction is performed until the retaining ring 24B provided integrally with the actuator 24A comes into contact with the main body of the solenoid 24 via a buffer (not shown) on the lower surface side of the main body of the solenoid 24 (for noise prevention).
As a result, the hook portion 18E locked with the locking pin 24 driven into the actuator 24A rotates clockwise, the second spring 23 is extended and displaced, and the transmission of the gear end 18A of the swing member 18 is performed. The gear 17 is separated from the fixing roller gear 6A1, and the driving force transmitted from the main body is not transmitted to the fixing unit.
[0043]
This operation is to temporarily stop the rotation of the fixing roller 6A as a means for shortening the start-up time of the fixing unit, for example, immediately after the power is turned on.
[0044]
Here, the components other than the actuator 24A, the swing member 18, the spring 20, and the second spring 23 do not change at all in comparison with the case of the normal position P1 shown in FIG.
Next, when the cover 1A is opened (the solenoid 24 is turned off), as shown in FIG. 6, the elastic operation end 20B of the spring 20 pushes the pressing end 19C of the interlocking operation member 19 by the stroke C (see FIG. 4B). After being inserted, it comes into contact with the operating end 18B of the swinging member 18, and pushes both the pressing end 19C and the operating end 18B in the clockwise direction in the drawing, thereby separating the transmission gear 17 from the fixing roller gear 6A1 as in FIG.
[0045]
Here, the moment due to the elastic force Fc of the spring 20 is set to be larger than the moment due to the elastic force Pb of the second spring 23 and the weight G of the actuator 24A and the swing member 18.
The time for energizing the solenoid 24 may be set to a predetermined time after the power is turned on, but the energization / non-energization may be determined by detecting the surface temperature or the internal temperature of the fixing roller 6A.
[0046]
The operating position of the solenoid 24, which is the driving means, is set on the basis of the above-described conditions, so that the transmission gear 17 and the fixing gear 6A1 can be closed when the cover 1 is in the closed position, independently of the open / closed state of the cover 1A. The meshing relationship can be changed. That is, when the main motor is started when the cover 1A is in the closed position, the operation state of the solenoid 24 is set corresponding to the timing, and the main motor is driven by the fixing roller 6A according to this operation state. The switching of the rotational driving force with respect to is performed. Thus, the rotation state of the fixing roller 6A can be controlled by using the main motor provided in the printer 1 without using a new driving source for the fixing roller 6A.
[0047]
In particular, when the printer 1 is started, that is, when the main motor is started, the transmission is performed for a predetermined time regardless of the warm-up rotation of the photosensitive member, which is a member other than the fixing roller 6A driven by the main motor, and the developing roller in the developing device. Since the transmission of the rotational driving force to the fixing gear 6A1 via the gear 17 can be released, when the fixing roller 6A rotates, the fixing roller 6A comes into contact with the pressure roller 6B and loses heat, so that the temperature of the fixing roller 6A is reduced. Can be prevented from decreasing, and the time required for the rise can be reduced, and the first (1st) print time can be shortened. In addition, when the temperature of the fixing roller 6A does not fall under the condition, in other words, when the temperature of the fixing roller 6A is close to the predetermined fixing temperature and when the temperature of the fixing roller 6A is the ambient temperature where the decrease of the fixing temperature is small, that is, when the internal temperature of the apparatus is lower than the predetermined temperature. When the temperature is close to the temperature (the ambient temperature during normal printing), the release operation is omitted, and the cost of the printer as a result of power consumption can be suppressed by eliminating the power consumption state. And the like.
[0048]
Although the printer 1 has been described as an image forming apparatus in the above description, a drive canceling device in a copier, a printer, a facsimile machine, a printing machine, or the like may be used instead. The operation and effect of the invention are obtained.
[0049]
【The invention's effect】
According to the first aspect of the present invention, in a drive release device in an image forming apparatus provided with a drive device that can use a single main motor as it is, a function of switching related parts of the drive release device is assembled and workability is improved. The operation stability can be improved. In particular, when the door is opened, the interlocking operation member that slides in conjunction with the door reduces or eliminates the pushing of the elastic operation end of the spring, so that the elastic operation end of the spring presses the operation end of the swing member, and Since the transmission gear of the moving member can be disengaged from the normal posture and switched to the driving release posture, when a jam occurs, the transmission of the driving force to the fixing roller can be released by operating only the interlocking operation member interlocking with the door. It becomes possible. Furthermore, the operating ends of the interlocking operation member and the swinging member are maintained in a state where they are not directly pressed, and the elastic operation end of the spring is interlockingly displaced in a pressing state only with the interlocking operation member, thereby comparing the elastic force of the spring itself. At this point, deformation over time can be prevented by reducing the load on the door on the image forming apparatus main body side. In addition, the spring can absorb the displacement of the door and the interlocking operation member, and does not require a separate spring for absorbing the displacement of the door.
[0050]
According to a second aspect of the present invention, the second spring switches the swinging member to a normal position when the pressing force of the spring does not work regardless of the posture of the swinging member and the transmission gear, and sets the transmission gear to the gear on the fixing means side. And the driving of the fixing unit can be reliably performed, and the degree of freedom of the layout of the second spring and the swinging member is increased.
[0051]
According to the third aspect of the present invention, even when other units such as the photosensitive drum and the developing roller of the image forming apparatus are being driven for pre-rotation while the door is closed, the forcible driving unit is turned on for a predetermined time, thereby causing the swinging operation. The moving member is switched, and the transmission gear of the oscillating member can be disengaged from the normal posture to be switched to the posture for releasing the drive. In this case, the escape of heat to the pressure roller can be suppressed to a minimum, the time required for rising can be reduced, and the first print time can be shortened.
[0052]
According to the fourth aspect of the present invention, the operability at the time of assembling and replacing can be facilitated by mounting the member driven by the electric signal as the forcible driving means together with the swinging member to the drive unit housing of the drive switching means.
[0053]
According to the fifth aspect of the present invention, it is determined whether or not to perform the drive release operation based on the roller temperature. Therefore, for example, when the roller temperature is close to the feasible fixing temperature, the release operation is omitted. If the internal temperature is close to the predetermined temperature, the release operation is omitted. If the temperature is lower than the guaranteed use temperature of the product, the release operation is omitted. Such control can be performed as needed, and the power for turning on the solenoid can be reduced, and the effect of preventing the movable section from deteriorating can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a printer as an image forming apparatus to which the present invention is applied.
FIG. 2 is a schematic side view of a driving force transmission unit including the driving release device of the printer of FIG.
FIG. 3 is a rear side view of the driving force transmission unit including the driving release device of the printer of FIG. 1;
4A and 4B show a state of a drive release device in a normal position of the drive force transmission unit in FIG. 1, where FIG. 4A is a sectional plan view of a main part and FIG. 4B is a side view of a main part.
FIG. 5 is a side view of a main part showing a state of the drive release device in the drive force transmission unit of FIG. 1 at a forced release position.
FIG. 6 is a side view of a main part showing a state at a release position of a drive release device in the drive force transmission unit of FIG. 1;
FIG. 7 is a schematic configuration diagram of a conventional device.
[Explanation of symbols]
1 Printer (image forming device)
5 Sheet conveying means
6 Fixing device
6A1 Fixing gear
10A Image forming apparatus main body
16 Idle gear
16B fulcrum shaft
17 Transmission gear
18 Swinging member (drive switching means)
18A Gear end
18B Operating end of rocking member
19 Interlocking operation members
20 Spring (drive switching means)
20B elastic operation end
P1 Regular position
P2 release position
P3 release forced position

Claims (5)

Sheet transporting means for transporting the sheet, fixing means for fixing the toner image transferred to the sheet, drive switching means for switching the driving force transmitting portion for driving the fixing means between driving force release and connection, and sheet conveyance failure. A door capable of opening and closing a part of the image forming apparatus main body wall for performing jam processing when a jam occurs, and a drive switching unit connected to the door and connected to the door when the door is closed. An interlocking operation member to be released when the door is opened; and
The drive switching means includes:
An oscillating member having an operation end provided opposite to the interlocking operation member and a gear end for pivotally supporting a transmission gear of the driving force transmission unit, the swinging member being pivotally supported via a fulcrum shaft in the image forming apparatus main body; A spring that has an elastic operation end that presses the operation end of the swinging member, and that urges the transmission gear at the gear end in a direction to separate from the gear on the fixing unit side;
and,
When the door is closed, the interlocking operation member pushes the elastic operation end of the spring to a predetermined position, and the state in which the elastic force of the spring is applied to the operation end of the oscillation member is reduced or eliminated, whereby the oscillation member is moved. The gear at the opposite end of the gear is maintained in a normal position for drivingly coupling with the gear on the fixing means side,
When the door is opened, the interlocking operation member reduces or eliminates the pushing of the elastic operation end of the spring, so that the transmission gear at the gear end of the swing member is disengaged from the gear on the fixing unit side in a drive release position. A drive release device in the image forming apparatus, wherein the drive is changed. A second spring that urges the swinging member with an elastic force in a direction opposite to the direction of swinging of the fulcrum about the fulcrum axis by the spring is stretched. 2. The drive release device in the image forming apparatus according to claim 1, wherein the elastic force around the fulcrum axis is set to be weaker. In a door closed state, a forced drive unit for forcibly swinging the swinging member from the normal posture toward the drive release posture when the door is opened is provided,
and,
2. The drive canceling device according to claim 1, wherein the forcible driving unit is operated to cancel the drive for a predetermined time immediately after the power of the image forming apparatus main body is turned on or after the door is closed. 4. The driving apparatus according to claim 3, wherein said forcible driving means is a member (solenoid) driven by an electric signal, and is mounted together with said swinging member on a driving unit housing of said driving switching means. Release device. The image forming apparatus further includes means for detecting an internal temperature or a fixing roller temperature of the image forming apparatus, and determines whether or not to perform the drive release operation based on the roller temperature when the door is closed or when the power is turned on. The drive canceling device in the image forming apparatus according to claim 3, wherein

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