JP4877955B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, or a printer that drives a fixing roller to fix the transferred toner image onto the transfer paper when a transfer paper carrying the transferred toner image is fed to the fixing roller. It is about.

In an electrophotographic image forming apparatus, an electrostatic latent image is formed on a photoreceptor and visualized with toner, and then the visualized toner image is transferred onto a transfer sheet. Thereafter, the transfer paper is passed through a fixing device to fix the toner image on the transfer paper.
The fixing device includes two rollers, a heating roller having a heat source therein and a pressure roller that is in pressure contact with the heating roller, and allows the transfer paper on which the toner image is transferred to pass through the nip portion of both rollers. . At this time, the toner image is fixed on the transfer paper by applying pressure while heating with a heating roller.

Here, since the heating roller comes into contact with the unfixed toner, a part of the toner adheres to it, and since it also comes into contact with the transfer paper surface, paper powder and the like also adhere. If the toner or the like fixed on the heating roller adheres to the transfer paper to be fed next, the image is soiled, and even if the toner or the like remains on the heating roller, problems such as offset are likely to occur.
Therefore, it is desirable to clean the heating roller. As a cleaning method, a method of removing foreign matter adhering to the heating roller using a heat-resistant web has been conventionally employed.

The web wound around the feed roller is wound on this by the winding roller. Then, cleaning is performed by pressing the web against the heating roller between the feeding roller and the take-up roller.
Two types have been proposed, in which cleaning is performed while winding with a winding roller and cleaning is performed with the winding roller being stationary (see, for example, Patent Documents 1 and 2).
However, the former type in which the cleaning is performed while winding is used, and the latter type in which the winding roller is stationary is mainly used at present because of the wasteful feeding and the speed of web replacement.

As a conventional example of such web feeding, in Patent Document 1, the web winding means is driven independently without being linked with other driving sources such as a fixing roller and a main motor of the image forming apparatus. The driving is performed only for a predetermined period during the operation period of the image forming apparatus. Further, in Patent Document 2, driving of the operation moving body is required for both forward rotation and reverse rotation, and the cleaning web is driven in such a manner as to follow it.
JP 59-84274 A Japanese Utility Model Publication No. 1-088862

However, in the conventional fixing device cleaning mechanism as described above, a separate drive source increases the cost. In addition, a mechanism that does not have a separate drive source but performs cleaning while winding the web with a take-up roller that is linked to another drive source results in a lot of wasted feed as described above, resulting in faster web replacement. .
In the prior art, driving of the operation moving body is required for both forward rotation and reverse rotation, and the cleaning web is driven in such a manner as to follow it. Therefore, the cleaning web operates even when it is not necessary, corresponding to the driving of the operation moving body. In addition, the amount of movement is also determined in accordance with the driving of the operation moving body, so that the cleaning web is fed too much, or conversely, the feeding is too little.

  Accordingly, an object of the present invention is to drive the two or more driven members to be driven by one driving source in consideration of the above-described situation, and to change the driven member to be driven depending on the rotation direction of the driving source. Thus, there is no need to have a separate drive source for the driven body to be driven only when necessary, and it is unnecessary to switch the drive of the driven body according to the rotation direction of the drive source. It is an object of the present invention to provide an image forming apparatus that can eliminate unnecessary driving, reduce torque, extend the replacement interval of consumables, and reduce power consumption.

In order to solve the above problems, the invention according to claim 1 is directed to a transfer toner image onto a transfer paper by driving the fixing roller when a transfer paper carrying a transfer toner image is fed to the fixing roller. In the image forming apparatus provided with a web for cleaning the fixing roller, the driving source can be switched between forward and reverse rotations in the rotation direction, and the fixing roller is connected to the driving source to drive the fixing roller. 1 drive mechanism , a second drive mechanism connected to the drive source to drive the web , and switching the drive transmission to and from the second drive mechanism according to the rotation direction of the drive source has a one-way clutch, and the drive-blocking means for blocking the drive transmission to the fixing roller in the fitting backlash gear pawl provided on the first drive mechanism, the said one-way clutch, said at reverse rotation of the drive source The drive to the web is transmitted, the drive to the web is cut off when the drive source is rotating forward, and the fixing roller is cleaned in a state where the web is stopped by the drive cut off, and the drive is transmitted. The drive shut-off means is characterized by an image forming apparatus that shuts off the driving of the fixing roller by the amount of fitting play when the web is wound up .

Also, the invention of claim 2, wherein the follower down-way clutch provided in the gear is a drive transmission member, according to claim 1 which is a driving transmission by engagement between gear provided within the second drive mechanism The image forming apparatus described above is characterized.

The invention according to claim 3, wherein the one-way clutch is provided on the pulley is a drive transmission member, the drive transmission between the pulleys provided within the second drive mechanism according to claim 1, wherein by the timing belt It said image forming apparatus.

The invention according to claim 4, wherein the drive source shall be the characteristic of the image forming apparatus of any one of claims 1 to 3 changing the rotational speed according to the rotation direction.
Also, an invention according to claim 5, wherein the driving source, wherein the image forming apparatus according to claim 4, wherein controlling the operation amount of the reverse in the number of fed sheets.

According to a sixth aspect of the present invention, there is provided the image forming apparatus according to the fourth aspect , wherein the drive source controls a reverse operation amount by an image area amount.
The invention described in Claim 7, wherein the driving source, wherein the image forming apparatus according to claim 4, wherein controlling the operation amount of the reverse and detects the contamination of the fixing roller.
The invention of claim 8, wherein the driving source, wherein the image forming apparatus according to claim 4, wherein controlling the operation amount of the reverse and detects the contamination of the web.
According to a ninth aspect of the present invention, the first drive mechanism has a pair of rotating rollers facing each other, and the fitting backlash of the gear claw is in the rotational circumferential direction of the end side surface of the one rotating roller. The image according to any one of claims 1 to 8 , comprising an arc-shaped concave portion provided in the concave portion and a convex portion provided on the other rotating roller fitted into the concave portion. Features a forming device.

  According to the present invention, in order not to drive the web, the drive mechanism is provided with a switching means for transmitting and interrupting the drive according to the rotation direction of the drive source to interrupt the drive to the web. When the drive source is reversed, the portion where the web contacts the fixing roller is changed by driving the web. As a precondition, it is assumed that no paper is passed through the fixing unit. At this time, since the fixing roller does not pass the sheet, the operation is not limited.

  In other words, the driving source drives the fixing roller during normal rotation, drives the web during reverse rotation, and has a mechanism that does not affect the other when one is driven. It can be driven by the amount. This makes it possible to give the web a necessary amount of drive only when necessary, eliminating unnecessary web feed and extending the web replacement time.

  By driving two or more to-be-rotated driven bodies with a drive source that can switch one rotation direction, the number of drive sources can be reduced, and the cost and space can be saved, depending on the rotation direction of the drive source. Since the drive of the driven body is switched, it is possible to reduce power consumption and extend the replacement interval of consumables.

  Further, as compared with driving the cleaning web from the drive source of the operating moving body, the driving of the web for cleaning is performed from the driving of the fixing roller to be cleaned. In this way, by taking drive from adjacent units, it is possible to reduce restrictions on the layout.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic front view showing an image forming apparatus provided with a driving device using the present invention. In FIG. 1, a latent image is formed on the photoreceptor 1 of the image forming apparatus A by the charging unit 2 and the writing unit 3, and the latent image is developed with toner by the developing device 4.
Transfer paper (not shown) is conveyed from the paper supply unit 5, timed by the registration unit 6, transferred to the toner image by the transfer unit 7, fixed by the fixing device 8, and discharged by the paper discharge unit 9. To a predetermined position.
The web device 10 is in contact with the heating roller 11 of the fixing device 8, and the heating roller 11 of the fixing device 8 is cleaned by a cleaning web (not shown). The fixing device 8 and the web device 10 are driven by a motor (not shown) that is the same drive source.

FIG. 2 is a perspective view showing a first embodiment of a driving device used in the image forming apparatus according to the present invention. FIG. 3 is a front view showing the driving device of FIG. FIG. 4 is a plan view showing the driving apparatus of FIG. 2 to 4 show a drive mechanism portion by gear coupling of the image forming apparatus.
2 to 4, a gear 13 is connected to the output shaft of the motor 12 that is a drive source, and the gear 13 is connected to two systems of drive mechanisms. The first drive mechanism 14 connects the rotational driving force transmitted from the gear 13 from the motor 12 to the gear 15, the gear 16, and the gear 17, and the first coupling shaft that rotates coaxially with the gear 17. 18 is a drive mechanism that rotates a first driven body (for example, a heating roller) (not shown).

The second drive mechanism 19 transmits the rotational driving force transmitted from the gear 13 from the motor 12 to the gear 20, the rotary shaft 21 coaxial with the gear 20, the gear 23 with the one-way clutch 22 coaxial with the gear 20, the gear 24, the second coupling shaft 25 rotating coaxially with the gear 24 is rotated, and thereby a second driven body (for example, a web device) (not shown) is rotated.
The one-way clutch 22 is used for switching between driving transmission and cutoff. When the motor 12 rotates in the forward direction, the rotational driving force from the motor 12 is cut off and not transmitted to the gear 23. 12 is a drive mechanism that transmits the rotational drive force from 12 to the gear 23.

When the motor 12 rotates in the forward direction, the gear 13 rotates in the reverse direction, and the first drive mechanism 14 side rotates in the forward direction, the reverse direction, and the forward direction with the gear 15, the gear 16, and the gear 17, respectively. The first rotation drive body (not shown) rotates forward as 18 rotates forward.
On the second drive mechanism 19 side, the gear 20 and the rotating shaft 21 are rotated forward. In this case, the one-way clutch 22 does not transmit the drive thereafter, and the gear 23, the gear 24, the second coupling shaft 25, and the second rotating driven body (not shown) do not rotate.

When the motor 12 rotates in the reverse direction, the gear 13 rotates in the forward direction, and the first drive mechanism 14 side rotates in the reverse direction, the forward direction, and the reverse direction with the gear 15, the gear 16, and the gear 17, respectively. Is reversed, the first rotated drive body (not shown) is reversed.
On the second drive mechanism 19 side, the gear 20 and the rotating shaft 21 are reversed. In this case, the one-way clutch 22 transmits the drive to the gear 23, and the gear 23 and the gear 24 are rotated in the reverse direction and the forward direction, respectively, and the second coupling shaft 25 is rotated in the forward direction. The rotational drive body rotates forward.

By using the one-way clutch 22 that is a one-way rotation restricting member as the switching means, there is no need to adopt a complicated configuration, and noise is reduced compared to a drive transmission switching mechanism that disconnects transmission of the clutch and the like, and the drive Avoiding collisions due to transmission contact and separation also leads to improved durability of the drive transmission member.
In addition, by using the one-way clutch 22 that is a one-way rotation restricting member, compared to a drive transmission switching mechanism that disconnects transmission of the clutch or the like, the durability is improved such that there is no gear chipping due to a collision, and an inexpensive material is used. The collision sound can be eliminated by eliminating the collision. Furthermore, by using a gear as the drive transmission member, it is possible to save resources at low cost without using a complicated configuration.

FIG. 5 is a perspective view showing a second embodiment of the driving device used in the image forming apparatus according to the present invention. FIG. 6 is a front view showing the driving device of FIG. FIG. 7 is a plan view showing the driving device of FIG. 5 to 7 show a driving mechanism unit by belt connection of the image forming apparatus.
With reference to FIGS. 5 to 7, two systems of drive mechanisms are connected to the output shaft of the motor 12, which is the drive source of the drive device. The third drive mechanism 26 connects the rotational driving force of the motor 12 to the geared pulley 27, the timing belt 28, and the pulley 29, and rotates the third coupling shaft 30 that rotates coaxially with the pulley 29. This is a drive mechanism that rotates a third driven body (not shown).

The fourth drive mechanism 31 generates a rotational drive force from the motor 12 by using a gear 32, a rotary shaft 33 coaxial with the gear 32, a pulley 35 with a one-way clutch 34 that is also coaxial with the gear 32, a timing belt 36, and a pulley 37. And a fourth coupling shaft 38 that rotates coaxially with the pulley 37 is rotated, thereby rotating a fourth driven member (not shown).
When the motor 12 rotates in the forward direction, the third drive mechanism 26 side is all reversely rotated with the geared pulley 27, the timing belt 28, and the pulley 29, and the third coupling shaft 30 is reversely rotated, so that a third not shown. The driven body of the motor rotates in the reverse direction.

On the fourth drive mechanism 31 side, the gear 32 and the rotating shaft 33 are reversed. In this case, the one-way clutch 34 does not transmit the drive thereafter, and the pulley 35, the timing belt 36, the pulley 37, the fourth coupling shaft 38, and the fourth rotation driven body (not shown) do not rotate.
When the motor 12 rotates in the reverse direction, the third drive mechanism 26 side normally rotates with the geared pulley 27, the timing belt 28, and the pulley 29, and the third coupling shaft 30 rotates in the forward direction and is not shown. The third driven body rotates forward.

  On the fourth drive mechanism 31 side, the gear 32 and the rotating shaft 33 are rotated forward. In this case, the one-way clutch 34 transmits the drive to the pulley 35, and all of the timing belts 36 and 37 are rotated in the forward direction, and the fourth coupling shaft 38 is rotated in the forward direction. Rotates forward. By using a combination of a pulley and a timing belt as the drive transmission member, a low backlash-less configuration can be achieved without a complicated configuration.

FIG. 8 is a perspective view showing a fixing device and a web device that can be operated by a driving device in the image forming apparatus according to the present invention. FIG. 9 is a front view showing the fixing device and the web device of FIG. FIG. 10 is a perspective view showing the fixing device and the web device. FIG. 11 is a schematic view showing a single unit of two gears in the fixing drive mechanism in perspective and a state in which they are combined in front.
8 and 9 show a fixing device and a web device that can be operated by the driving device using the present invention shown in FIG. The fixing device 8 (FIG. 1) is provided with a heating roller 11 and a pressure roller 39, and the heating roller 11 and the pressure roller 39 rotate in conjunction with each other. The surface of the heating roller 11 is coated with a heat-resistant release layer such as PFA or PTFE.
Further, a heater (not shown) is provided inside the heating roller 11, and the heating roller 11 is maintained at a certain constant temperature by this heater. The gear 41 (a in FIG. 11) and the gear 42 (b in FIG. 11) in the fixing drive mechanism 40 are the mechanisms shown in FIG.

When the convex part of the gear 42 is inserted into the concave part of the gear 41 (c in FIG. 11) and the motor 43 is rotated in the reverse direction, as shown by the arrow shown in FIG. Prevents reversal. In addition, by performing the one-way rotation restriction with the backlash of the gear claw, it is possible to provide a low-cost configuration with a simple combination of parts.
The transfer paper (not shown) is linked to the heating roller 11 whose rotation is transmitted by the fixing drive mechanism 40 further including a gear 48, a belt 49, a gear 50, a gear 51, and a gear 52, and in contact with the heating roller 11. It is conveyed to the pressure roller 39 that performs. In that case, the toner is fixed by applying heat and pressure at the nip portion between the heating roller 11 and the pressure roller 39.

The web device 10 (FIG. 1) includes a sheet-like heat-resistant web 44, a pressing roller 45 that presses the web 44 against the heating roller 11, a take-up roller 46 that winds up the web (cleaning web) 44, and supply of the web 44 A feeding roller 47 as a means is arranged, and the winding roller 46 and the feeding roller 47 rotate in conjunction with each other.
In addition, a unidirectional rotation preventing member (not shown) is attached to the winding roller 46 so that the wound web 44 is not pulled out. The web 44 is impregnated with a release material, and is pressed against the heating roller 11 by the pressing roller 45, thereby cleaning unfixed toner, paper powder and the like adhering to the heating roller 11 and releasing the release material onto the heating roller 11. Apply.

Further, the web 44 is taken up by a take-up roller 46 to which rotation is transmitted by the web drive mechanism 53 and supplied by a feed roller 47 when necessary, so that a new web portion is brought into contact with the heating roller 11. Cleaning can be performed.
The web drive mechanism 53 includes a one-way clutch 54, gears 55 and 56, an output shaft 57 of the motor 43, and gears 58, 59 and 60. The motor 43, which is the same drive source for the fixing device 8 and the web device 10, can rotate forward and reverse, and transmits drive to the fixing drive mechanism 40 and the web drive mechanism 53.
In the web drive mechanism 53, the gear 55 provided with the one-way clutch 54 as described above is used as a drive transmission member. The one-way clutch 54 cuts off driving during normal rotation and transmits driving during reverse rotation.

10 shows a heating roller 11 and a pressure roller 39 constituting the fixing device 8 (FIG. 1), a transfer paper P sent between them, a pressing roller 45 constituting the web device 10 (FIG. 1), and a winding. A take-out roller 46, a feed roller 47, and a web (cleaning web) 44 are shown.
The driving of the web device 10 requires a smaller driving amount and a lower driving speed than the driving of the fixing device 8, and therefore the motor 43 has a smaller rotational speed during reverse rotation than during normal rotation.

Note that the amount of reverse rotation can be controlled by the number of sheets passed by a counter of a main body control unit (not shown). In this way, by controlling the amount of reverse rotation by the number of sheets, the amount of reverse rotation of the drive source (motor 43) can be controlled without having a detection mechanism or the like inside, and space saving and cost reduction are possible. It becomes.
The reverse operation amount can also be controlled by the image area amount measured by a main body control unit (not shown). In this way, by controlling the amount of reverse rotation by the amount of image area, that is, the amount of toner used, by controlling the amount of toner used, the efficiency can be improved compared to the case of controlling by the number of sheets to be passed. .

Further, the reverse operation amount can be controlled by detecting contamination of the heating roller 11 with a sensor (not shown). In this way, space can be saved and costs can be reduced by controlling the amount of reverse rotation of the drive source (motor 43) without having a detection mechanism or the like inside.
The amount of reverse rotation can also be controlled by detecting dirt on the web 44 with a sensor (not shown). By controlling the web drive amount by the reverse rotation of the drive source (motor 43) by detecting the dirt on the web, it is possible to prevent the fixing roller from being cleaned by the dirty web and to increase the efficiency.
Therefore, when the motor 43 rotates in the forward direction, the web drive mechanism 53 blocks the drive to the web apparatus 10 by the one-way clutch 54, the web 44 is pressed against the heating roller 11 in a stopped state, and the heating roller 11 rotates in the reverse direction. To do.
In this case, the roller surface of the heating roller 11 is rubbed against the web 44, and unfixed toner, paper powder, etc. adhering to the heating roller 11 are cleaned, and a release material is applied.

Further, when the motor 43 rotates in the reverse direction, the web drive mechanism 53 transmits the drive to the web device 10, the web 44 is wound around the take-up roller 46, and the heating roller 11 is fitted to the backlash of the gear 41 and the gear 42. If the rotation is not transmitted by the minute, and the rotation is given more, it will rotate forward.
In this case, the web 44 is taken up by the take-up roller 46, and a new part of the web 44 comes into contact with the heating roller 11. The heating roller 11 is cleaned and a release material is applied.

  According to the present invention, at least two to-be-rotated driving bodies are driven by one driving source, and the at least one to-be-rotated driving body to be driven by the rotation direction of the driving source can be selected. By using a one-way clutch or a gear with a loose fit for the mechanism, various rotating driven bodies that are to be driven only when necessary are driven by a single drive source, thereby reducing costs, resources, and savings. Energy conversion is possible.

  According to the present invention, by using a drive source capable of changing the number of rotations according to the direction of rotation, the rotation of the driven body driven at the time of reverse rotation is compared with the number of rotations of the driven body driven at the time of forward rotation. When the number is small or large, deceleration and acceleration using a gear train, a pulley, or the like can be kept small, and cost reduction, space saving, and resource saving can be achieved.

  According to the present invention, by using a drive mechanism that drives the web only during reverse rotation, it is possible to extend the web replacement period without wasteful web feeding compared to the case where the web is always driven. . Furthermore, since torque and energy can be reduced, cost reduction, resource saving, and energy saving can be achieved.

  According to the present invention, the amount of toner adhering to the fixing roller depending on the usage environment, usage status, age, etc. of the image forming apparatus is determined by detecting the contamination of the fixing roller by controlling the web driving amount due to the reverse rotation of the driving source. Regardless of the variation, it becomes possible to control the driving amount of the web, reduce the wasteful web feed, and save resources.

It is a schematic front view which shows the image forming apparatus provided with the drive device which uses this invention. 1 is a perspective view showing a first embodiment of a drive device used in an image forming apparatus according to the present invention. It is a front view which shows the drive device of FIG. It is a top view which shows the drive device of FIG. It is a perspective view which shows 2nd Embodiment of the drive device used for the image forming apparatus by this invention. It is a front view which shows the drive device of FIG. It is a top view which shows the drive device of FIG. FIG. 3 is a perspective view showing a fixing device and a web device that can be operated by a driving device in the image forming apparatus according to the present invention. It is a front view which shows the fixing device and web apparatus of FIG. It is a perspective view which shows a fixing device and a web apparatus. FIG. 5 is a schematic view showing a single unit of two gears in the fixing drive mechanism in perspective and a state in which they are combined in front.

Explanation of symbols

  A image forming apparatus, 1 photosensitive member, 4 developing device, 7 transfer unit, 8 fixing device, 10 web device, 11 fixing roller (heating roller, first driven member to be rotated), 12 driving source (motor), 13 driving Transmission member (gear), 14 1st drive mechanism (drives fixing roller), 18 1st coupling shaft, 19 2nd drive mechanism (drives web), 22 Switching means (1-way rotation restricting member, one-way) Clutch), 23 drive transmission member (gear), 25 second coupling shaft, 26 third driving mechanism, 27 pulley with gear, 28 timing belt, 30 third coupling shaft, 39 fixing roller (pressure roller) ), 40 First drive mechanism (fixing drive mechanism), 41 Drive transmission member (gear), 42 Drive transmission member (gear), 43 Drive source (motor), 44 Web (climate) Training web, a second driven rotatable member), 53 a second drive mechanism (web drive mechanism), 54 switching means (1 direction rotation restricting member, the one-way clutch), 55 drive transmission member (gear)

Claims (9)

An image forming apparatus including a web for cleaning the fixing roller, which drives the fixing roller to fix the transferred toner image onto the transfer paper when a transfer paper carrying the transfer toner image is fed to the fixing roller. In
One drive source capable of switching between forward and reverse rotation in the rotation direction;
A first drive mechanism coupled to the drive source for driving the fixing roller ;
A second drive mechanism coupled to the drive source for driving the web ;
A one-way clutch that switches drive transmission and disconnection to the second drive mechanism in accordance with the rotational direction of the drive source;
Drive blocking means for blocking drive transmission to the fixing roller by a gear claw engagement play provided in the first drive mechanism ,
The one-way clutch transmits the drive to the web when the drive source is reversely rotated, and interrupts the drive to the web when the drive source is normally rotated.
The web performs cleaning of the fixing roller in a state where it is stopped by the interruption of the drive, and is wound by transmission of the drive.
The image forming apparatus characterized in that the drive shut-off means shuts off the driving of the fixing roller by the amount of looseness when the web is wound . The image forming apparatus according to claim 1, wherein the one-way clutch is provided in a gear which is a drive transmission member, and is driven by engagement with the gear provided in a second drive mechanism . Provided pulley before SL one-way clutch is in drive transmission member, an image forming apparatus according to claim 1, wherein the drive transmission between the pulleys provided within the second drive mechanism is characterized in that by the timing belt. The image forming apparatus according to claim 1 , wherein the driving source changes a rotation speed in accordance with a rotation direction . The image forming apparatus according to claim 4 , wherein the drive source controls a reverse operation amount by a number of sheets . The image forming apparatus according to claim 4 , wherein the drive source controls a reverse operation amount by an image area amount. The image forming apparatus according to claim 4 , wherein the driving source controls a reverse operation amount by detecting contamination of the fixing roller . The image forming apparatus according to claim 4 , wherein the drive source controls a reverse operation amount by detecting dirt on the web . The first drive mechanism has a pair of rotating rollers facing each other,
The gear claw fitting backlash is composed of an arc-shaped concave portion provided in the circumferential direction of the end surface of one rotating roller and a convex portion provided on the other rotating roller fitted into the concave portion. the image forming apparatus according to any one of claims 1 to 8, characterized in that it is.

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