JPH08171286A - Transfer belt cleaning device - Google Patents

Abstract

PURPOSE: To provide a transfer belt cleaning device capable of surely cleaning the whole region of the toner carrying surface of a transfer belt, even if it is deviated by meandering and preventing a failure in cleaning and damage to the driving system of the transfer belt, even if a blade is rolled up. CONSTITUTION: The width H of a cleaning blade 20 for cleaning the surface of the transfer belt 13 is set to be the meandering range or more of the transfer belt 13. In the cleaning blade 20, a slit 20s is formed in the boundary part of a first cleaning edge part 20A corresponding to the end part of the transfer belt 13 in its meandering range and a second cleaning edge part 20B corresponding to the effective image range of the belt 13 except the first cleaning edge part 20A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer belt cleaning device such as a copying machine, a printer or a facsimile, which uses an electrostatic transfer system.

[0002]

2. Description of the Related Art Conventionally, a transfer conveyance method for transferring a toner image formed on a photoconductor such as a copying machine, a printer or a facsimile by an electrostatic transfer method onto a transfer paper and at the same time electrostatically adsorbing and transferring the transfer paper. As a device, a transfer belt composed of an endless dielectric belt having a predetermined electric resistance value stretched by a driving roller and a driven roller, a high-voltage power supply for applying an electric charge to the transfer belt, and a surface of the transfer belt. A transfer conveyance device having a cleaning member for cleaning is known.

Further, as a cleaning device for cleaning the surface of the transfer belt in this transfer conveyance device,
Various devices using a cleaning blade such as a reading system or a counter system and a cleaning member such as a fur brush have been proposed.

[0004]

In the conventional cleaning device, for example, the width of the transfer belt is 33.
0mm, effective image width 297mm (A4 size width)
, The width of the effective image area of this transfer belt (29
If it is possible to completely clean (7 mm) with the cleaning member, it seems that the cleaning purpose can be achieved.

However, in an actual transfer / transport device,
Since the transfer belt meanders due to its rotation and the effective image area of this transfer belt is offset in the width direction, if the width of the cleaning member is set to 297 mm as described above, the meandering of the transfer belt causes both ends of the effective image area to move. The toner of the portion protruding to the outside is not removed by the cleaning member and remains attached to both ends of the transfer belt.

Therefore, in such a cleaning device, the toner on the transfer belt cannot be completely removed, and the toner remaining and accumulated on both ends of the transfer belt is scattered to contaminate the periphery of the transfer conveyance device. . Further, in such a cleaning device, for example, when a user comes into contact with the transfer belt during removal or maintenance of jammed paper, the operator's hand or sleeve is also contaminated by the toner adhering to the end of the transfer belt. There is a defect.

The present invention has been made in view of the above-mentioned points, and an object thereof is to ensure the entire area of the toner carrying surface of the transfer belt in consideration of the deviation due to the meandering of the transfer belt in advance. An object is to provide a transfer belt cleaning device that can be cleaned.

That is, the object of the present invention is to preliminarily anticipate the deviation in the width direction of the effective image area due to the meandering of the transfer belt, and to perform cleaning to a width greater than the maximum width including the deviation when the transfer belt meanders. This can be achieved by setting the width of the member and ensuring that the cleaning member corresponds to the entire area of the transfer belt.

However, when a counter type cleaning blade is used as the cleaning member for the transfer belt, the cleaning edge of the cleaning blade abuts at an acute angle toward the upstream side in the rotational direction of the transfer belt. If the width of this cleaning blade is set to be larger than the maximum width of the transfer belt, the cleaning edge of the cleaning blade, which is abutted by both ends of the transfer belt, causes the cleaning edge to flip up to the downstream side. It will be easier. this is,
Since both ends of the cleaning blade protruding from both ends of the transfer belt are placed in an unloaded state even when the transfer belt is rotated, the edge part corresponding to the end of the transfer belt is deformed inside the transfer belt surface, and the transfer It is considered that the rotation of the belt makes it easier for the belt to be rolled into the downstream side.

Therefore, in the counter type cleaning blade, as described above, if the width thereof is simply made larger than the width of the transfer belt, the blade turning phenomenon easily occurs, and the cleaning blade comes into contact with the transfer belt. There are problems that the conditions are not appropriate and cleaning failure occurs, or the sliding resistance of the cleaning edge with respect to the transfer belt increases and the drive system of the transfer belt is damaged due to overload.

Another object of the present invention is to provide a transfer belt cleaning device which does not cause cleaning failure or damage to the transfer belt drive system even if the blade is turned over.

[0012]

In order to solve the above-mentioned problems, the present invention provides, in claim 1, an endless shape having a predetermined electric resistance value stretched by a photosensitive member, a driving roller and a driven roller. Of the toner image formed on the photoconductor, having a transfer belt formed of a dielectric belt, a high-voltage power supply for applying an electric charge to the transfer belt, and a cleaning member for cleaning the surface of the transfer belt. In a transfer transport device that electrostatically attracts and transports the transfer paper at the same time as transferring the transfer paper, a cleaning member for cleaning the surface of the transfer belt is set to have a width not smaller than the meandering range of the transfer belt. The cleaning blade has a cleaning edge.

According to a second aspect of the present invention, the cleaning member has a first cleaning edge portion corresponding to an end of the transfer belt within a meandering range of the transfer belt, and a portion other than the first cleaning edge portion. A counter type cleaning blade having a slit is formed at the boundary with the second cleaning edge portion corresponding to the effective image area of the transfer belt.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings. First, with reference to FIGS. 8 to 15, a transfer conveyance device using a transfer belt according to the present invention will be described.

In FIG. 8, the transfer sheet 11 which has been fed to the registration roller 10 and is on standby is the photosensitive drum 12
Registration roller 1 at the same timing as the top of the image above
It is sent out from 0. The transfer belt 13 is usually separated from the photosensitive drum 12.

When the leading end of the transfer paper 11 comes close to the contact portion of the photosensitive drum 12 with the transfer belt 13, the contact / separation lever 14 is pushed up by a DC solenoid (not shown) as shown in FIG. Abut on the drum 12. At this time, a nip n having a width of 4 to 8 mm is formed at the contact portion between the transfer belt 13 and the photosensitive drum 12.

Then, as shown in FIG.
The transfer bias is applied to the transfer bias roller 15 in accordance with the job timing when the toner enters the nip portion, and the transfer belt 13 is transferred with a polarity opposite to that of the toner 16 on the photoconductor drum 12. Done. This time,
Since the transfer paper 11 is attracted to the transfer belt 13, it is separated from the photoconductor drum 12 and is carried on the transfer belt 13. In this apparatus, the developing roller 17 develops the positive toner 16 on the photosensitive drum 12 whose surface is charged to −800 V, and the PTL 18 causes the photosensitive drum 12 to develop.
Of the transfer bias roller 15 after the surface potential of
Then, a high voltage is applied to transfer the toner 16 onto the transfer paper 11.

Further, since the transfer belt 13 in this apparatus has a medium resistance, the charges applied to the transfer belt 13 and the transfer paper 11 are as shown in FIG.
As the transfer belt 13 moves to the downstream side in the traveling direction, the contact plate 19 removes electric charge. This transfer method is controlled by a constant current method, and performs stable transfer / separation in response to changes in paper type, environment, and belt surface resistance value.

In this apparatus, as described above, the transfer belt 13 is brought into contact with and separated from the photoconductor drum 12 in accordance with the paper passing timing of the transfer paper 11, but the toner on the non-transfer paper portion during the repeat or The toner adhered on the photoconductor drum 12 due to the scattering and other causes is transferred onto the transfer belt 13.

In order to scrape off the adhered toner from the transfer belt 13, as shown in FIG.
Like the cleaning unit (not shown) of the transfer belt 1
The cleaning blade 20 is brought into contact with the cleaning roller 3 to clean the toner adhering to the transfer belt 13. This cleaning blade 20 is a counter type, and in order to prevent the blade from being turned up (blade entrainment),
The surface of the transfer belt 13 is coated to reduce the friction coefficient.

Further, as shown in FIG. 13, a cleaning lever 2 integrated with a spring is provided on the shaft of the cleaning blade 20 on the front side of the blade supporting member 21.
2 is attached, and when this cleaning lever 22 is operated, as shown by the broken line in FIG. 12, the edge portion of the tip of the cleaning blade 20 contacts the left seal 23, and the cleaning edge 20a of the cleaning blade 20 is Be refreshed. As shown in FIG. 13, the cleaning lever 22 is in contact with the positioning plate 24 of the transfer belt unit, and is rotated by about 30 degrees when the unit is released such as when a paper jam occurs. Is refreshed. Further, as shown in FIG. 12, the left seal 23 for refreshing the cleaning edge 20a is similar to the right seal 25 disposed on the downstream side of the cleaning unit, and is configured to prevent toner scattering from the cleaning unit. In order to prevent it, it also has a function of sealing the cleaning part.

By the way, as shown in FIG. 14, in the elastic rubber belt, when the friction coefficient between the roller A and the belt B is relatively high, the outer shape of the roller A is a crown shape (the diameter of the central portion is larger than the diameter of both ends). The shape of the belt B is such that the belt B tends to be closer to the larger diameter (center) of the roller A. Therefore, in this apparatus, the transfer belt 13 is used as shown in FIG. 15 by utilizing the property of the belt B.
Of the drive roller 26 and the driven roller 27 for stretching and rotating the driven roller, both ends of the driven roller 27 are formed in a taper shape to hold the transfer belt 13 at a position substantially in the center of the driven roller 27. Is configured to keep.

However, since this principle depends on the elastic force of rubber and the coefficient of friction between the belt B and the roller A, the toner and the like enter the inside of the belt B and the belt B
When the friction coefficient between the roller A and the roller A is lowered,
The function of the belt B trying to shift to the center of the roller A becomes insufficient, and the belt B is biased or meanders. For this reason,
In this type of belt transfer / conveyance device, it is necessary to clean the rollers 26 and 27 when the transfer belt 13 is replaced.

By the way, in an actual transfer conveyer, the transfer belt 1 is formed by the taper portion provided on the driven roller 27.
The running stability in the center of 3 is not completely maintained, and for example, the parallelism between the driving roller 26 and the driven roller 27, the cylindricity (roundness) of the transfer belt 13, and the like. Since the dimensional error causes variations in each component, the transfer belt 13 is stably run in a state slightly offset to the front side or the back side from the center between the rollers 26 and 27.

As described above, the transfer belt 13 meanders due to its rotation, and its effective image area is offset in the width direction. Therefore, when the width of the cleaning blade 20 is set equal to the width of the transfer belt 13, The toner that has protruded outside both ends of the effective image area due to the meandering is not removed by the cleaning blade 20 and remains attached to both ends of the transfer belt 13.

Therefore, in such a cleaning device, the toner on the transfer belt 13 cannot be completely removed, and
The periphery of the transfer / transport device is contaminated by the scattering of the toner remaining and accumulated on both ends of the transfer belt 13. This toner scattering causes a reduction in the coefficient of friction between the transfer belt 13 and each of the rollers 26 and 27, so that the meandering or deviation of the transfer belt 13 is further increased.

Therefore, in the transfer belt cleaning device of the present invention, as shown in FIG. 1, the deviation of the effective image area in the width direction (indicated by a broken line) due to the meandering of the transfer belt 13 and the variation in the dimensions of the parts is previously set. Considering this, the width H of the cleaning blade 20 is set to a width equal to or larger than the maximum width Hmax including the deviation when the transfer belt 13 meanders, and the cleaning edge 20a surely corresponds to the entire area of the transfer belt 13. To configure.

For example, as shown in FIG. 2, the transfer belt 1
When the width Ha of the effective image area of No. 3 is 297 mm (horizontal width of A4 size), the width Hb of the transfer belt 13 is 330 mm, and the deviation amount d of the transfer belt 13 due to variation is ± 10 mm, the width of the cleaning blade 20 is 350 for H
Set to mm (or more).

According to this cleaning blade 20,
Even if the transfer belt 13 is deviated, the surface (toner bearing surface) of the transfer belt 13 can be reliably cleaned over the entire area, and no toner remains on the transfer belt 13. It is possible to solve the problem that occurs as a cause.

Here, the same effect can be obtained regardless of whether the cleaning system of the cleaning blade 20 is the reading system shown in FIG. 3A or the counter system shown in FIG. 3B. it can.

Further, as the cleaning method in this apparatus, as shown in FIG. 4, for example, brush cleaning using a brush roller 28, bias cleaning using a bias roller or an adhesive roller, adhesive cleaning, or the like can be used. If the widths of the rollers are set in consideration of the deviation of No. 13, the same effect as in the above embodiment can be obtained.

However, when the counter type cleaning blade 20 is used as the cleaning member for the transfer belt 13, the cleaning edge 20a of the cleaning blade 20 faces the upstream side in the rotational direction of the transfer belt 13. And the width H of the cleaning blade 20 is set to be equal to or larger than the maximum width Hmax of the transfer belt 13. Therefore, as described above, both ends of the transfer belt 13 contact the cleaning blade 20. At both end portions, a blade-turning phenomenon in which the cleaning edge 20a is turned up to the downstream side is likely to occur.

Therefore, in the transfer belt cleaning device of the present invention, as shown in FIGS.
Of the first cleaning edge portion 20A corresponding to the end portion of the transfer belt 13 within the meandering range, and the second cleaning edge portion 20B corresponding to the effective image range of the transfer belt 13 other than the first cleaning edge portion 20A. The cleaning blade 20 is formed by forming a slit 20 s at the boundary between the cleaning blade 20 and.

For example, as shown in FIG. 5, when the width of the cleaning blade is set to 350 mm, the slit 20s is 25 from both ends of the cleaning blade 20.
It is provided at each mm. In addition, each slit 20
The width of s is about 0 to 0.5 mm, and the slit 2
It is taken into consideration that the cleaning performance of the cleaning blade 20 is not deteriorated due to the formation of 0a and stains due to the slits 20s are not generated.

In FIG. 5, assuming that the meandering amount (deviation amount) of the transfer belt 13 is ± 10 mm, this transfer belt 1
The edge portions of both ends of 3 sandwich the slit 20s of the cleaning blade 20 and meander at the first cleaning edge portions 20A on both outer sides.

Therefore, in the present embodiment, even if a blade turning phenomenon occurs from both ends of the cleaning blade 20, the turning edge portion of the cleaning edge 20a caused by this phenomenon is, as shown in FIG. Is fixed only to the outer first cleaning edge portion 20A, and the effective image area of the transfer belt 13 (width 297 m
m) second cleaning edge portion 20B
Transfer belt 1 as it cannot be turned up to (width 300mm)
The toner carried within the effective image range of 3 can be cleaned without any trouble.

Here, under the above-described conditions, the position of the slit 20s may theoretically be 20 mm from both ends of the cleaning blade 20, but by setting this to 25 mm, the transfer belt 13 is offset. Even when the amount is 20 mm, the edge portions of both ends of the transfer belt 13 are not caught in the slits 20s of the cleaning blade 20, and the second cleaning edge portion 20B corresponding to the effective image area of the transfer belt 13 is removed. You can more reliably prevent the blade from turning over.

Further, an experiment of cleaning the transfer belt 13 having a width of 330 mm by a counter method with two types of cleaning blades having a width of 350 mm and 320 mm was carried out. In combination with the transfer belt 13 having a width of 330 mm, the blade is liable to be turned up especially at a high temperature, and the width is 320 mm.
With the combination of the cleaning blade 20 and the transfer belt 13 having a width of 330 mm, the blade was not turned up.

Here, in all cases where the blade was turned over, the blade was turned over where the edge portion of the end portion of the transfer belt 13 hits the cleaning edge 20a of the cleaning blade 20.

Further, the cleaning blade 20 having a width of 320 mm, in which the blade is not turned up, and the width of 330 m
m in combination with the transfer belt 13, the transfer belt 1
The scattered toner adhered to both ends of No. 3 as black band-like stains. The portion of the transfer belt 13 to which the toner adheres was the portion where the cleaning edge 20a of the cleaning blade 20 was not in contact.

[0041]

As described above, according to the present invention, in claim 1, even if the transfer belt is offset, the surface (toner carrying surface) of the transfer belt can be reliably cleaned over the entire area. Since the toner does not remain on the transfer belt 13, the scattering of the toner causes the contamination of the periphery of the transfer / transport device, the removal of jammed paper, and the sleeve of the operator's hands during maintenance. It can eliminate pollution.

According to the second aspect, even if the blade swelling phenomenon occurs from both ends of the cleaning blade, the swelling portion of the cleaning edge caused by this phenomenon is retained only at the first cleaning edge portion outside the slit. Since the second cleaning edge portion corresponding to the effective image area of the transfer belt is not turned over, the toner carried in the effective image area of the transfer belt can be cleaned without any trouble.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a first embodiment of a transfer belt cleaning device according to the present invention.

FIG. 2 is a schematic front view showing the specifications of the first embodiment.

FIG. 3 is a schematic side view showing a cleaning system of the first embodiment.

FIG. 4 is a schematic perspective view showing another cleaning method of the first embodiment.

FIG. 5 is a schematic front view showing the specifications of the second embodiment of the transfer belt cleaning device according to the present invention.

FIG. 6 is a schematic perspective view showing a cleaning operation of the second embodiment.

FIG. 7 is a schematic perspective view showing how blades are turned up during the cleaning operation of the second embodiment.

FIG. 8 is a schematic side view of a transfer / transport device in which the present invention is implemented.

FIG. 9 is a schematic side view showing a sheet feeding process of the transfer / conveyance device in which the present invention is carried out.

FIG. 10 is a schematic side view showing a transfer step of the transfer / transport device in which the present invention is carried out.

FIG. 11 is a schematic side view showing another aspect of the transfer step of the transfer / transport device in which the present invention is carried out.

FIG. 12 is a schematic side view showing a cleaning process of the transfer belt of the transfer / transport device in which the present invention is carried out.

FIG. 13 is a schematic perspective view of a cleaning unit of a transfer belt of the transfer / conveyance device in which the present invention is implemented.

FIG. 14 is a schematic explanatory diagram of a transfer belt deviation prevention mechanism of the transfer / transport device in which the present invention is implemented.

FIG. 15 is a schematic side view of a transfer belt deviation prevention mechanism of the transfer / transport device in which the present invention is implemented.

[Explanation of symbols]

 13 transfer belt 20 cleaning blade 20a cleaning edge 20A first cleaning edge portion 20B second cleaning edge portion 20s slit 21 blade support member 26 drive roller 27 driven roller 28 brush roller d transfer belt offset amount H cleaning blade width Ha Width of effective image area of transfer belt Hb Width of transfer belt Hmax Maximum width including offset of transfer belt

Claims (2)

[Claims] 1. A transfer belt composed of a photoconductor, an endless dielectric belt having a predetermined electric resistance value stretched by a driving roller and a driven roller, and a high-voltage power supply for applying an electric charge to the transfer belt. And a cleaning member for cleaning the surface of the transfer belt, which transfers the toner image formed on the photoconductor onto the transfer paper and at the same time electrostatically attracts and transfers the transfer paper. The transfer belt cleaning device, wherein the cleaning member for cleaning the surface of the transfer belt comprises a cleaning blade having a cleaning edge set to have a width not less than a meandering range of the transfer belt. 2. The cleaning member comprises a first cleaning edge portion corresponding to an end portion of the transfer belt within a meandering range of the transfer belt, and an effective image of the transfer belt other than the first cleaning edge portion. 2. The transfer belt cleaning device according to claim 1, wherein the transfer belt cleaning device comprises a counter type cleaning blade having a slit formed at a boundary portion with the second cleaning edge portion corresponding to the range.