JPS6244274B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a cleaning device for cleaning the surface of an object to be cleaned, such as a photosensitive drum or an insulating drum, and particularly to a cleaning device using a cleaning web. 2. Description of the Related Art Conventionally, in image forming apparatuses such as electrophotographic copying machines, residual toner on an object to be cleaned is cleaned using a cleaning web made of nonwoven fabric or the like. FIG. 1 is a diagram schematically showing such a conventional web cleaning device, in which 1 is an object to be cleaned, 2 is a cleaning web, and 3 is a pressure roller made of an elastic body for pressing this web against the object to be cleaned 1. , 4 is a web winding shaft, and 5 is a feeding shaft. However, when the web is wound up by rotating the winding shaft 4 at a constant rate with the above configuration, the amount of web feed differs between the beginning and the end of winding.
In other words, as shown in the graph of the change in web feed amount with respect to the change in the diameter of the web take-up shaft in Fig. 2, when the diameter of the take-up shaft changes from d ₀ at the start of winding to d ₁ at the end of winding, the The amount of web feed per unit time changes from the initial value _l0 to the final value _l1 . At this time, the feed amount is set so that complete cleaning can be performed even with the minimum value _l0 . Therefore, if the feed amount is l ₀ or more, the web is being fed by an amount greater than the required amount, and this shortens the web replacement interval of the web cleaning device. In other words, it has become a drawback that shortens the lifespan. In order to solve this problem, a method can be considered in which the web is held between rollers 6 rotating at a constant speed to feed the web at a constant rate, as shown by the broken line in FIG. This method is well known in the field of tape recorders and the like. However, in the case of a web cleaning device, unlike a tape recorder, such an extremely precise feeding speed is not required.
Further, in addition to at least a take-up shaft, a feed-out shaft, and a pressure roller, one roller that rotates at a constant speed is required. Moreover, in order to realize this method, it is necessary to apply tension to the web to prevent the web from sagging, that is, to rotate the winding shaft 4 a little faster than the roller 6. Therefore, two driving sources are required. Moreover, if the torque of the winding shaft 4 becomes greater than that of the roller 6, the roller 6 will be useless and the amount of web winding will be determined by the winding shaft. In order to prevent this, it is necessary to provide a sliding mechanism etc. on the winding shaft to absorb a large amount of winding, but this makes the device complicated and
It has the disadvantage of increasing costs. The present invention solves the problem that the pressure contact state of the pressure contact member that presses the cleaning web against the object to be cleaned changes due to drive transmission when winding up the web. A swingable device that integrally holds a shaft, a pressing member that presses the web against the object to be cleaned, a take-up shaft that winds up the web after being pressed, and a transmission mechanism that transmits rotational force to the take-up shaft. a holding member; a cam that rotates to abut the cam follower and provide driving force to the cam follower of the rotational force transmission mechanism; This cleaning device is characterized in that the pivot axis of the holding member is disposed on or near a straight line connecting the two. Embodiments of the present invention will be described below with reference to the drawings. Embodiments of the present invention are shown in FIGS. 3 to 5. Third
The figure is a perspective view of a cleaning device according to an embodiment of the present invention, FIG. 4 is a side view of the device shown in FIG. 3 as seen from the direction of arrow G, and FIG. , FIG. 5B is a schematic diagram showing the swing angle of the swing lever. First, the configuration of this embodiment will be explained. In the figure, 7
The cleaning web is made of conventionally known materials such as woven or non-woven fabrics made of synthetic resin. This web is wound around a feed shaft 8 in large quantities, and is wound onto a winding shaft 10 via a pressure roller 9 made of a material such as foamed polyurethane. These shafts 8, 10 and the shaft 9a of the pressure roller 9 are integrally and rotatably attached to holding plates 11, 12 which are holding members. As shown in FIG. 4, the holding plate 11 has one support shaft 1 protruding from a side plate (not shown) of the image forming apparatus.
3, and can swing around this support shaft 13. A spring 14 is hung on the holding plate 11, and this spring is directed in the direction of pressing the pressure roller 9 against the object to be cleaned 1, that is,
It acts in the H direction in the figure. This spring 14 may be hung on the shaft 9a. The holding plate 12 is connected to the feeding shaft 8 and the winding shaft 1.
0 and three stays 15a, 15b, 15c
(See FIG. 3 and FIG. 5A) is fixed to the holding plate 11. Between these holding plates 11 and 12, there is provided a rotational force transmission mechanism that transmits rotational force in only one direction to the web winding shaft and a regulating member that regulates the web winding amount to a nearly constant value according to the present invention. ing. In FIG. 5A and FIG. 3, 16 is the rotating shaft 1
The eccentric cam attached to 7 rotates in the direction of arrow I. Cam follower 1 in contact with this cam 16
8, and this cam follower 18 is rotatably attached to one end of a swing lever 19 attached to the winding shaft 10. Swing lever 19
One end of the spring 20 is hung on the other end, and the other end of the spring 20 is hung on a dowel 21 set up on the holding plate 12. Therefore, the cam follower 18 is pressed against the cam 16 by the action of the spring 20. 22 is fixed on the winding shaft 10 by a ratchet, a driving claw 23 for advancing the ratchet 22 is attached to the swing lever 19, and a reversal prevention claw 24 for preventing reverse rotation of the ratchet 22 is attached to the dowel 21, respectively. ing. In this embodiment, these ratchets 22, claws 2
3 and 24 constitute a rotational force transmission mechanism. In addition, a lever 25, which is a regulating member that regulates the amount of web feed, is swingably attached to the dowel 21, and a lever 25 at its tip is used to detect changes in the amount of web winding, specifically, the diameter of the winding shaft. A detection rod 26 that acts as a detection section is fixedly planted. This detection rod 26 is moved around the outer circumference of the web on the winding shaft 10 (indicated by reference numeral 28 in FIGS. 3 and 5A) by the action of a spring 27 applied to a lever 25.
It has come to be in constant contact with the When the web is wound up and the winding shaft diameter increases, lever 2
5 swings in the direction of arrow J (FIG. 5A), the contact position between the detection rod and the swing lever 19 changes accordingly, the swing angle of the swing lever 19 is regulated, and the winding The amount of rotation of the take-up shaft gradually decreases, and the web is fed almost a fixed amount without being over fed. That is, the detection rod 26 also functions as a regulating section. As shown in FIG. 5, if the support shaft 13 is placed near the line P connecting the center of the cam shaft 17 and the point of action of the cam (a in the figure), the pressure on the pressure roller 9 will change due to the action of the cam. can be prevented from happening. Next, the operation of the apparatus of this embodiment based on the above configuration will be explained. When the cam 16 rotates at a constant cycle in the direction of arrow I in synchronization with the paper feed of the image forming apparatus, the swing lever 19, which is in contact with the cam 16 via the cam follower 18, first moves as the cam 16 is displaced. Swings (rotates) in the direction of arrow K. Then, the ratchet 22 is moved by the driving claw 23 provided on the swing lever 19 and whose tip engages with the ratchet 22.
rotates in the direction of arrow L, and the web is wound up. Then, when the cam 16 rotates further and exceeds its uppermost point, the swing lever 19 swings in the direction of arrow M and returns to its original position. However, at this time, the other claw, that is, the reverse rotation prevention claw 24, is engaged with the ratchet 22, so that the ratchet 22 is prevented from rotating in the opposite direction, and the web is not fed in the opposite direction than usual, and the pressure roller This prevents slack between the winding shaft 9 and the winding shaft 10. Here, the return position of the swing lever 19 is determined by the detection rod 2 pressed against the outer periphery of the web by the spring 27.
6. When the number of webs on the winding shaft 10 increases and the outer diameter thereof becomes thicker, the detection rod 26
rotates in the direction of arrow J, the return position of the swing lever 19 changes, and the angle at which the lever 19 rotates next time (θ in FIG. 5B) decreases. The angle at which the swinging lever rotates in the K direction when pushed by the cam is determined by the shape of the cam, so by reducing the return angle of the swinging lever, the web winding shaft 10
The rotation angle of decreases. It is generally known that as the outer diameter of the winding shaft increases, the amount of winding per unit rotation angle increases. Therefore, with the structure of this embodiment, the amount of web to be wound up is approximately constant regardless of the outer diameter of the web. In other words, the outer diameter x rotation angle = web feed amount, so the rotation angle is decreased in response to an increase in the outer diameter. Examples of numerical values in experiments using the apparatus of this embodiment are shown in the table below and FIG. 6.

[Table] As is clear from comparing Fig. 6 with Fig. 1 of the conventional example, the outer diameter of the web winding shaft varies from d ₀ to d ₁ .
Even if the web feed rate changes to , the web feed amount only changes slightly between l ₀ and l ₂ . According to the experimental example in the table above,
During the time it takes to copy 100 sheets of A4 size (JIS standard) paper, the feed amount only moves back and forth between approximately l ₀ = 2.0 mm and l ₂ = 3.0 mm, and a nearly constant feed amount can be maintained. In the above experimental example, the number of teeth on the ratchet was 90, but the larger the number of teeth, the smaller the range of variation between the web feed amounts _l0 and _l2 . Furthermore, the following effects are achieved regarding the lifespan (usage time) of the web. First, when the rotation of the winding shaft is not restricted, for example, when the winding shaft rotates at a constant speed as shown in FIG. 2, the initial diameter of the winding shaft d ₀ =
φ14mm, at this time 2mm per 100 sheets of A4 paper (l ₀ = 2
mm/100 sheets) When sending a web, the web thickness D = 0.06 mm, the web length L = 20 m, the final diameter of the take-up shaft d ₁ = φ41.5 mm, and it takes only the time to copy approximately 500,000 sheets. I was able to use this web. Incidentally, the final web feed amount l ₁ = 5.9 mm/100 sheets. However, in the case of the previous embodiment device according to the present invention, the same conditions, ie, d ₀ =φ14 mm, d ₁ =φ41.5
mm, l ₀ = 2 mm/100 sheets, D = 0.06 mm, L = 20 m,
We were able to extend the lifespan to approximately 800,000 sheets. By the way, in the above description of the embodiment, an example was shown in which the change in the diameter of the web winding shaft is detected to regulate the rotation (swing) angle of the swing lever, but as shown in FIG. The rotation angle of the swing lever may be regulated by detecting a decrease in the outer diameter of the web feed shaft. In the figure, reference numeral 29 denotes a lever, which is swingably installed on the swing center shaft 30, and includes a detection rod 31 that touches the outer periphery of the web 7 on the web feed shaft 8 to detect changes in the outer diameter, and a swing lever. The lever 19 has a regulating rod 32 that comes into contact with the lever 19 to regulate the angle at which the lever 19 rotates. A spring 33 is attached to the lever 29.
is hung so that the detection rod 31 is brought into pressure contact with the outer periphery of the web 7. Note that the regulating rod 32 may be in contact with the outer periphery of the web similarly to the embodiments shown in FIGS. 3 to 5. Similarly, in the embodiments shown in FIGS. 3 to 5, the detection rod and the regulation rod may be provided separately as shown in FIG. 7. In the embodiment shown in Figs. 3 to 5, the ratchet and pawl are used as the rotational force transmission mechanism for transmitting rotation in only one direction to the winding shaft. The clutch may be engaged to transmit rotational force in only one direction. The use of a one-way clutch allows the web feed to be approximately constant rather than serrated as shown in FIG. In addition to drum-shaped or endless belt-shaped photoreceptors, objects to be cleaned that can be applied to the present invention include
Toner adheres to the surfaces of insulators used in screen-based electrophotographic devices, or magnetic drums, fixing rollers, etc. in devices that obtain images using magnetic latent images, as described in Publication No. 133841, etc., and it is necessary to wipe it off. Including everything that has. In particular, when the present invention is applied to a fixing roller cleaning device, the fixing roller becomes quite hot, so
It is preferable to use ratchet, which has excellent heat resistance. At this time, it is preferable to use Nomex (trade name) nonwoven fabric for the web because it has excellent cleaning performance, can be made thin, and has heat resistance. In addition, when a ratchet is used, it saves a considerable amount of space compared to a one-way clutch, so the device can be made more compact, and it is also preferred because it does not have the play angle found in one-way clutches. In addition to the roller-shaped member, a pad-shaped member can also be used as the web pressing member in the present invention. As can be understood from the above embodiments, the characteristic configuration of the cleaning device of the present invention is that the cleaning web delivery shaft, the web pressure contact member, the web take-up shaft, and the holding member that integrally holds the rotational force transmission mechanism are rocked. On or in the vicinity of a straight line connecting the center of the cam shaft, which is the center of rotation of a rotary cam that is movably supported and provides driving force by contacting the cam follower of this rotational force transmission mechanism, and the point of action of this cam on the cam follower. By arranging the pivot axis of this holding member,
Even when the driving force is transmitted by the cam, the cleaning web can be kept in stable pressure contact with the object to be cleaned, and a good cleaning effect can be obtained over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional web cleaning device, FIG. 2 is a graph showing changes in web feed amount with respect to changes in the diameter of the web take-up shaft, and FIG. 3 is a perspective view of a cleaning device according to an embodiment of the present invention. ,
4 is a side view of the device shown in FIG. 3 as seen from the direction of arrow G; FIG. 5A is a sectional view taken along line V-V of the device shown in FIG. 3;
FIG. 5B is a schematic diagram showing the swing angle of the swing lever, FIG. 6 is a graph showing changes in web feed amount with respect to changes in the winding shaft diameter according to the present invention, and FIG. 7 is another embodiment of the present invention. FIG. In the figure, 1... object to be cleaned, 7... cleaning web, 8... delivery shaft, 9... pressure roller, 10... winding shaft, 11, 12... holding plate, 13... support shaft, 14 ... Spring, 16 ... Cam, 18 ... Cam follower, 19 ... Swing lever, 22 ... Ratchet, 23 ... Drive claw, 24
...represents a reverse rotation prevention claw, 25...a lever, 26...a detection rod.

Claims (1)

[Claims] 1. A delivery shaft for delivering a cleaning web;
A swingable holding member that integrally holds a pressure contact member that presses the web against the object to be cleaned, a winding shaft that winds up the web after pressure contact, and a transmission mechanism that transmits rotational force to this winding shaft. and a cam that rotates in order to contact and apply a driving force to the cam follower of this rotational force transmission mechanism, and connects the center of the cam shaft, which is the center of rotation of this cam, and the point of action of this cam on the cam follower. A cleaning device characterized in that a swing center axis of the holding member is arranged on a straight line or in the vicinity thereof.