JP3403816B2 - Transfer transfer device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer / conveying device which can be applied to an image forming apparatus such as a copying machine, a facsimile or a printer which employs an electrostatic transfer system.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a facsimile, and a printer which employs an electrostatic transfer system, an endless belt which comes into contact with an image carrier and onto which an image on the image carrier is transferred, and the endless belt. A transfer including a plurality of supporting means for stretching and rotating the endless belt, a charge applying means for applying a transfer charge to the endless belt, and a cleaning means for contacting the endless belt and cleaning the surface of the endless belt. Transport devices are known.
For example, it is as described in JP-A-2-110586.

FIG. 6 shows an example of the transfer / transport device.
In FIG. 6, reference numeral 100 denotes a transfer belt which is an endless belt, faces a photoconductor 99 which is an image carrier rotating in the direction of the arrow in the figure, and contacts the photoconductor 99 at a predetermined position. Are arranged as follows. The transfer belt 100 has, at one end thereof, a driving roller 102 which is one of a plurality of supporting means.
And the other end is stretched and supported between a driven roller 101, which is one of a plurality of supporting means, and by a driving roller 102,
Rotate in the direction of the arrow in the figure. The transfer roller 103, which is a charge applying unit, is located downstream of the contact position between the transfer belt 100 and the photoconductor 99, contacts the back side of the transfer belt, and applies the transfer charge to the transfer belt. . The transfer belt 1 is placed at a position facing the drive roller 102.
A cleaning blade 104, which is a cleaning unit that cleans the surface of 00, is provided as a counter in the moving direction of the transfer belt.

The transfer process is as follows. The photosensitive member 99 having a toner image formed on its surface rotates, and the transfer sheet waiting at the registration roller 105 is sent out at the timing when the leading end of the sheet and the leading end of the toner image coincide with each other at the transfer position. A transfer bias is applied to the transfer roller 103 at the timing when the leading edge of the sheet enters the nip portion formed at the contact portion between the photoconductor 99 and the transfer belt 100, and the transfer sheet electrostatically attracted onto the transfer belt 100 is applied to the transfer sheet. Toner is transferred by electrostatic force. After that, the transfer sheet is subjected to curvature separation at the portion of the driving roller 102 and is sent to a fixing unit (not shown).

On the other hand, although it is rare that extra toner adheres to the transfer belt, when the toner adheres to the transfer belt, the transfer belt is cleaned by a cleaning blade as with the photoconductor and is transferred onto the transfer belt. It is necessary to remove the toner.

[0006]

In order to ensure the cleaning performance of the transfer belt in the above-described transfer / transport device, the width of the cleaning blade in the direction orthogonal to the stretching direction of the transfer belt is set to be smaller than the width of the transfer belt in the same direction. Was also set large. On the other hand, due to the dimensional tolerance of the structure that constitutes the transfer / conveyance device, that is, the dimensional tolerance of the processed article itself and the assembling of the article, deterioration of the transfer belt and the like with time, environmental change, and the like, the transfer belt meanders or shifts.

Since the width of the cleaning blade is larger than the width of the transfer belt, the contact surface of the cleaning blade with the transfer belt is constantly rubbed against the edge of the transfer belt, and the transfer belt is meandered or offset. Therefore, the cleaning blade is worn by the transfer belt. When the cleaning blade becomes worn, it is easy for the blade to flip over from the worn portion, and when the blade is turned up, the cleaning blade is pressed against the transfer belt with excessive force, increasing the drive load on the transfer belt and increasing the drive system. It causes a great deal of damage. Further, the transfer belt is in a poor cleaning state.

The present invention solves the above technical problems, and suppresses meandering or deviation of the transfer belt with a simple structure as much as possible.
A first object of the present invention is to provide a transfer conveyance device in which the cleaning blade is not worn by the transfer belt.

Further, in addition to the first object, the present invention provides
A second object of the present invention is to provide a transfer conveyance device in which the transfer roller is arranged so that the toner contacts the blade over the entire width of the cleaning blade, and the contact friction state between the cleaning blade and the transfer belt is kept constant over the entire width of the cleaning blade. And

In order to achieve the above object, the present invention is configured as follows.

The width (W) in the direction orthogonal to the stretching direction of the endless belt, the effective image area width (I) of the image carrier, and the width (C) of the cleaning means in the direction orthogonal to the stretching direction of the endless belt. ),
And the width (S) of the supporting means in the direction orthogonal to the stretching direction of the endless belt is set to satisfy the relation of I≤C <S <W (claim 1).

The width (W) in the direction orthogonal to the stretching direction of the endless belt, the effective image area width (I) of the image carrier, and the width (C) of the cleaning means in the direction orthogonal to the stretching direction of the endless belt. ),
Further, the width (T) of the charge applying means in the direction orthogonal to the stretching direction of the endless belt is set to satisfy the relation of I≤C <T <W (claim 2).

The width (W) in the direction orthogonal to the stretching direction of the endless belt, the effective image area width (I) of the image carrier, and the width (C) of the cleaning means in the direction orthogonal to the stretching direction of the endless belt. ),
The width (S) of the support means in the direction orthogonal to the stretching direction of the endless belt and the width (T) of the charge giving means in the direction orthogonal to the stretching direction of the endless belt are I ≦ C <T ≦ S. <W is set (claim 3).

[0013]

According to the invention of claim 1, the width (C) of the cleaning means in the direction orthogonal to the stretching direction of the transfer belt is set to the width (S) of the driving and driven rollers in the direction orthogonal to the stretching direction of the transfer belt. By making the width (W) in the direction orthogonal to the stretching direction of the transfer belt larger than the width (S) of the driving and driven rollers, it is possible to easily meander or offset the transfer belt. While being suppressed as much as possible by the structure, the transfer belt does not wear the cleaning means .

According to the second aspect of the present invention, the width (C) of the cleaning means in the direction orthogonal to the stretching direction of the transfer belt is larger than the width (T) of the transfer roller in the direction orthogonal to the stretching direction of the transfer belt. By making the width (W) in the direction orthogonal to the stretching direction of the transfer belt smaller than the width (S) of the drive and driven rollers, the meandering or deviation of the transfer belt can be simplified. While suppressing as much as possible, the contact friction state between the cleaning means and the transfer belt is kept constant over the entire width of the cleaning means , and the blade is not turned up.

According to the third aspect of the invention, the width (C) of the cleaning means in the direction orthogonal to the stretching direction of the transfer belt is larger than the width (T) of the transfer roller in the direction orthogonal to the stretching direction of the transfer belt. The width (T) of the transfer roller is smaller than the width (S) of the driven roller that is driven in the direction orthogonal to the stretching direction of the transfer belt, and is the width of the direction orthogonal to the stretching direction of the transfer belt. By making (W) larger than the width (S) of the driving and driven rollers, it is possible to suppress the meandering or deviation of the transfer belt with a simple configuration while using the transfer belt.
No wear of the cleaning means and blade flipping occurs.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the outline of one embodiment of the present invention. The main configuration of the transfer / transport device 20 will be described. Reference numeral 21
Indicates a transfer belt which is an endless belt, and is arranged so as to face the photoconductor 11 which is an image carrier rotating in the direction of the arrow in the figure and to contact the photoconductor 11 at a predetermined position. . The transfer belt 21 has one end stretched between a driving roller 22 which is one of a plurality of supporting means and a driven roller 23 which is one of a plurality of supporting means, and the other end of which is a driving source via a gear or the like. It is rotationally driven in the direction of the arrow in the figure by the drive roller 22 connected to. The transfer roller 24, which is a charge applying unit, is connected to a high-voltage power supply, is located downstream of the contact position between the transfer belt 21 and the photoconductor 11, contacts the back side of the transfer belt, and transfers to the transfer belt. It gives an electric charge. Further, a cleaning blade 28, which is a cleaning unit that cleans the surface of the transfer belt 21, is provided at a position facing the driven roller 23 as a counter in the transfer belt moving direction.

The image forming process will be briefly described.
The photoconductor drum 11 is rotationally driven by a motor (not shown) and uniformly charged by the charging device 12, and then is optically written by image exposure by the optical writing unit 13 to form an electrostatic latent image. This electrostatic latent image is developed by a developing device 14 with a developer containing a predetermined color, for example, black toner, to form a black toner image.

The photoconductor 11 is uniformly charged by the charging device 15 after passing through the developing device 14, and the optical writing unit 1
Optical writing is performed by image exposure by 6 to form an electrostatic latent image. This electrostatic latent image is developed by the developing device 17 with a developer containing a toner of a color different from the black color to form a toner image of a color different from the black color. As described above, the two sets of charging devices 12, 15, the optical writing parts 13, 16 and the developing devices 14, 17 constitute a toner image forming means for forming a toner image on the photoconductor 11, and these toner image forming means. May use one set of charging device, optical writing unit and developing device. The photoconductor 11 is discharged by the pre-transfer charge eliminator 18 after passing through the developing device 17.

The transfer sheet is fed from the sheet feeding device to the registration roller 19, and the registration roller 19 sends out the transfer sheet in accordance with the toner image on the photoconductor 11. The transfer sheet is sent from the registration roller 19 to the transfer belt 21 in which a transfer electric field is generated by the transfer bias applied from the transfer roller, and the transfer sheet is electrostatically adsorbed to the transfer belt 21 and conveyed to the transfer position. At the transfer position, the toner image is electrostatically transferred from the photoconductor 11 to the transfer sheet by the transfer electric field, and then the transfer sheet is separated from the photoconductor 11. The separation claw 25 physically separates the transfer sheet that has not been separated from the photoconductor 11 from the photoconductor 11.

The transfer sheet is conveyed by the transfer belt 21 and separated from the transfer belt 21 at the driving roller 22. A toner image is fixed on the separated transfer sheet by a fixing device (not shown), and the transfer sheet is discharged to the outside.

Here, although the amount of surplus toner that directly adheres to the transfer belt is small, when the toner image on the photoconductor does not match the transfer sheet size due to the irregular size of the transfer sheet, or the size of the transfer sheet is small. When a jam occurs, it is directly transferred from the photoconductor to the transfer belt,
Also, a small amount of toner adhering to the area outside the image area on the surface of the photoconductor (for example, the space between papers) may be directly transferred from the photoconductor to the transfer belt. The cleaning device includes the cleaning blade 28 and the cleaning brush 29. Thirty
Is arranged on the downstream side in the rotation direction from the transfer sheet separating position on the transfer belt 21. Cleaning blade 2
8 is in contact with the transfer belt 21 in the counter direction,
Cleaning blade 28 and cleaning brush 29
Cleans the transfer belt 21 after separating the transfer sheet, and removes toner, paper dust, etc. on the transfer belt 21.

The cleaning blade 28 is made of polyurethane rubber, and has good cleaning performance, no damage to the transfer belt, excellent abrasion resistance, resistance to hydrolysis and ozone deterioration, and excellent durability. .

The details of the invention described in each claim will be described with reference to FIGS. The invention according to claim 1 will be described. 2 and 3, the transfer belt 21 is stretched and supported between the driving roller 22 and the driven roller 23 having a dimension length shorter than the length of the transfer belt 21 in the direction orthogonal to the belt stretching direction. There is.

From FIGS. 5A and 5B, the transfer belt 21
The length of the transfer belt 21 in the direction orthogonal to the belt stretching direction is longer than the length of the driving roller 22 and the driven roller 23 in the direction orthogonal to the belt stretching direction. The so-called ears are formed by protruding the length Δd on both sides from the end of the roller 23. The tension at the ears of the transfer belt 21 is driven by the drive roller 22.
Since the tension at the contact portion with the driven roller 23 and the driven roller 23 becomes smaller, the belt rotation support mechanism composed of the drive roller 22 and the driven roller 23 is used for the belt rotation transfer belt 21.
It has a function to suppress the meandering and stopping of the. In the above embodiment, the driving roller 22 and the driven roller 23 have a cylindrical shape, and the predetermined radius R is formed on the peripheral edge of the driven roller 23, but the roller shape may be a drum shape.

Here, when the transfer belt is continuously rotated for a long time in the structure of FIGS. 5 (a) and 5 (b), the driving roller 22 and the driven roller 2 of the transfer belt 21 change with time.
There is a possibility that a slight crack may occur at the edge bent portion A corresponding to the position of the end portion of No. 3.

Although the crack does not affect the durability of the belt itself, if the cleaning blade and the crack are in constant contact with each other, the surface of the cleaning blade is abraded due to the contact with the crack, and the worn portion concerned. The blade is more likely to be turned over.

Therefore, as shown in FIGS. 2 and 3, the dimension length of the cleaning blade 28 in the direction orthogonal to the belt stretching direction is the dimension of the driving roller 22 and the driven roller 23 in the direction orthogonal to the belt stretching direction. The cleaning blade 28 is set to a length shorter than the length, and even if a crack is generated in the edge-folded portion A of the transfer belt 21, the cleaning blade 28 is arranged at a position where it does not come into contact with the crack. This prevents abnormal wear of the end portion of the cleaning blade 28 and stabilizes the cleaning property.

FIG. 4 shows the relationship between the lengths of the above members in an easy-to-understand manner. The width of the transfer belt 21 in the direction orthogonal to the stretching direction is (W), the effective image area width of the photoconductor 11 is (I), and the width of the cleaning blade 28 in the direction orthogonal to the stretching direction of the transfer belt 21 is ( C) and the width of the drive roller 22 in the direction orthogonal to the stretching direction of the transfer belt are (S), the length relationship of each member is set to I ≦ C <S <W. In the experiment, (W) = 342 mm, (I) = 304
mm, (C) = 312 mm S) = 326 mm, and when the transfer belt is continuously rotated for a long time, meandering and deviation of the belt are suppressed, abnormal wear of the end of the cleaning blade is prevented, and stable cleaning performance is achieved. I was able to get

The invention according to claim 2 will be described. Figure 2
Also, from FIG. 3, the transfer belt 21 is in contact with the transfer roller 24 having a dimension length shorter than the length of the transfer belt 21 in the direction orthogonal to the belt stretching direction, and through the contact portion,
It is supported by the transfer roller 24.

Because the length of the transfer belt 21 in the direction orthogonal to the belt stretching direction is longer than the length of the transfer roller 24 in the direction orthogonal to the belt stretching direction, for the same reason as described in claim 1 above. An ear portion is formed at the end of the transfer belt 21, and a function of preventing meandering and deviation when the belt is rotated is imparted to the transfer belt 21, and the transfer belt 24 suppresses the meandering and deviation to some extent by the transfer roller 24.

Further, since the transfer belt 21 and the cleaning blade 28 are in contact with each other, frictional force is generated at the contact portion. This frictional force acts on the cleaning blade 28 in a direction in which the blade tip is hung in the transfer belt rotation direction and the tip is rolled up, and acts on the transfer belt 21 as a force for suppressing the rotation of the belt. However, if both act excessively, a problem may occur in the transfer / transport device.

As a result, it has been found that the frictional force is reduced by the toner directly attached to the transfer belt. In the case of the transfer / transport device of the present application, the frictional force is held on the transfer belt 21 from the photoconductor 11. At the time of transfer to the transfer sheet, a small amount of toner is directly transferred onto the transfer belt 21,
This transfer toner reduces the frictional force between the transfer belt 21 and the cleaning blade 28.

The above-mentioned adhered toner is mainly present on the effective image area of the transfer belt, so that the cleaning blade 28 is used.
There is little toner adhesion in the edge area of the blade, and there is a possibility that the frictional force is still not sufficiently reduced at the blade edge.

Therefore, as shown in FIGS. 2 and 3, the dimension length of the transfer roller 24 in the direction orthogonal to the belt stretching direction is slightly smaller than the dimension length of the cleaning blade 28 in the direction orthogonal to the belt stretching direction. The length of the transfer roller 2 is set to a long value so that the transfer roller 2 can be set at both end positions of the cleaning blade 28.
A transfer bias from No. 4 is applied, a transfer electric field acts, and a slight amount of excess toner is transferred from the photoconductor 11. As a result, even at the end of the cleaning blade 28, the frictional force with the transfer belt 21 is reduced, and the blade can be prevented from turning over.

FIG. 4 shows the relationship between the lengths of the above members in an easy-to-understand manner. The width of the transfer belt 21 in the direction orthogonal to the stretching direction is (W), the effective image area width of the photoconductor 11 is (I), and the width of the cleaning blade 28 in the direction orthogonal to the stretching direction of the transfer belt 21 is ( C) and the width of the transfer roller 24 in the direction orthogonal to the stretching direction of the transfer belt 21 are (T), the length relationship of each member is set to I ≦ C <T <W. In the experiment, (W) = 342 mm, (I) = 30
4 mm, (C) = 312 mm (T) = 322 mm, and when the transfer belt is continuously rotated for a long time, meandering and deviation of the belt are suppressed and the frictional force between the blades is reduced, and the blades are turned up. And stable cleaning properties could be obtained.

The invention according to claim 3 will be described. still,
The dimensional length relationship between each member other than the dimensional length relationship of the drive roller 22, the driven roller 23, and the transfer roller 24 in the direction orthogonal to the belt stretching direction is the same as the above-described claim 1 and claim 2. Is.

2 and 3, the dimensional length of the transfer roller 24 in the direction orthogonal to the belt stretching direction is determined by the drive roller 2
2 and the driven roller 23 are set to be shorter than the dimension length in the direction orthogonal to the belt stretching direction.

Since the dimensional length of the transfer roller 24 in the direction orthogonal to the belt stretching direction is shorter than the dimensional length of the drive roller 22 in the direction orthogonal to the belt stretching direction, the transfer belt 21 in contact with the transfer roller 24. The contact area of is uniformly stretched over the entire width of the transfer roller 24 by a constant tension. Therefore, the transfer roller 24 comes into contact with the transfer belt 21 in a uniform state without waviness, flexure, and the like, and applies a transfer charge, so that a uniform transfer electric field is formed and stable transferability is obtained.

FIG. 4 shows the relationship between the lengths of the above members in an easy-to-understand manner. The width of the transfer belt 21 in the direction orthogonal to the stretching direction is (W), the effective image area width of the photoconductor 11 is (I), and the width of the cleaning blade 28 in the direction orthogonal to the stretching direction of the transfer belt 21 is ( C), if the width of the transfer roller 24 in the direction orthogonal to the stretching direction of the transfer belt 21 is (T) and the width of the drive roller 22 in the direction orthogonal to the stretching direction of the transfer belt is (S), each member The relationship of the lengths of I is C ≦ T
≦ S <W is set. In the experiment, (W) = 342
mm, (I) = 304 mm, (C) = 312 mm, (T) = 3
22mm, (S) = 326mm, when the transfer belt is continuously rotated for a long time, meandering and deviation of the belt is suppressed, the frictional force between the blade and the belt is reduced, and the blade can be prevented from curling and is stable. It was possible to obtain the transferability and cleaning property.

[0040]

As described above, according to the first aspect of the invention, meandering and deviation of the belt of the transfer / conveying device are suppressed and
Abnormal wear at the end of the cleaning means was prevented, and stable cleaning properties could be obtained.

According to the second aspect of the present invention, meandering and deviation of the belt are suppressed, the frictional force between the cleaning means and the belt is reduced, the blade is prevented from being turned over, and stable cleaning property can be obtained. .

According to the second aspect of the invention, meandering and deviation of the belt are suppressed, the frictional force between the cleaning means and the belt is reduced, the blade is prevented from being turned over, and stable transferability and cleaning performance are obtained. I was able to.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

FIG. 2 is a perspective view showing the same embodiment.

FIG. 3 is a plan view showing the same embodiment.

FIG. 4 is a side view showing the same embodiment.

FIG. 5 is a side view showing a tension structure of a transfer belt.

FIG. 6 shows a conventional example.

[Explanation of symbols]

11 photoconductor 21 transfer belt 22 Drive roller 24 Transfer roller 28 Cleaning blade

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 15/16 G03G 21/10

Claims (3)

(57) [Claims] 1. An endless belt, which is in contact with an image carrier and onto which an image on the image carrier is transferred, and an edge fold portion at an end position.
And a plurality of supporting means for stretching and rotating the endless belt, and a cleaning means for contacting the endless belt and cleaning the surface of the endless belt. The width (W) in the direction orthogonal to the stretching direction of the image carrier, the effective image area width (I) of the image carrier, the width (C) of the cleaning unit in the direction orthogonal to the stretching direction of the endless belt, and A transfer / conveyance device, wherein a width (S) of the supporting means in a direction orthogonal to a stretching direction of the endless belt is set to a relation of I ≦ C <S <W. 2. An endless belt which is in contact with an image carrier and on which an image on the image carrier is transferred, a plurality of supporting means for stretching and rotating the endless belt, and the endless belt. In a transfer conveyance device having a charge applying unit for applying a transfer charge and a cleaning unit for contacting the endless belt and cleaning the surface of the endless belt, a width in a direction orthogonal to a stretching direction of the endless belt. (W), effective image area width (I) of the image carrier, width (C) of the cleaning means in a direction orthogonal to the stretching direction of the endless belt, and orthogonal to the stretching direction of the endless belt. The width (T) of the charge applying unit in the direction of the transfer is set to satisfy the relation of I ≦ C <T <W. 3. An endless belt, which is in contact with an image carrier and on which an image on the image carrier is transferred, a plurality of supporting means for stretching and rotating the endless belt, and the endless belt. In a transfer conveyance device having a charge applying unit for applying a transfer charge and a cleaning unit for cleaning the surface of the endless belt, a width (W) in a direction orthogonal to a stretching direction of the endless belt, the image carrier Effective image area width (I), width of the cleaning means in a direction orthogonal to the stretching direction of the endless belt (C), width of the supporting means in a direction orthogonal to the stretching direction of the endless belt ( S) and the width (T) of the charge applying means in the direction orthogonal to the stretching direction of the endless belt are set to satisfy the relation of I ≦ C <T ≦ S <W.