JP3446404B2 - Image forming 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 belt conveying means for conveying a transfer material for transferring a toner image by an insulating endless belt in an image forming apparatus such as a copying machine, a facsimile machine, a printer, etc., which uses an electrophotographic method or the like. The present invention relates to an image forming apparatus that employs.

[0002]

2. Description of the Related Art As an image forming apparatus of this type, a belt conveying means is arranged so that an insulating belt for conveying a transfer material is stretched between a plurality of rolls having at least a driving roll and a tension applying roll. The transfer material is electrostatically adsorbed on the insulating belt by using a charging device or the like and conveyed, and a toner image formed on the image carrier by an electrophotographic method or the like is transferred to the transfer material. There is one that forms an image by transferring.

However, in the image forming apparatus adopting such a belt conveying means for conveying the transfer material, the parallelism between the rolls due to the arrangement of the rolls around which the belt is stretched, the roll cylinder precision, and the both side ends of the belt. Due to the difference in the circumferential length of the belt, a phenomenon in which the belt moves in a direction perpendicular to the conveying direction, that is, a meandering phenomenon occurs, and the toner image transferred to the transfer material on the belt is biased due to the occurrence of the meandering phenomenon. There is a problem that a good image cannot be obtained.

Therefore, conventionally, a spring is movably supported in the axial direction of the roll between a side portion of the tension applying roll and a supporting member for supporting the roll, and a spring is interposed between the supporting member and the supporting member. Provide a belt end guide member,
An apparatus has been proposed in which the guide member is configured to elastically support the belt end portion. According to this device, the belt is driven while contacting the elastically supported guide member,
At this time, the meandering of the belt is controlled by the guide member moving along the unevenness of the belt end portion.

[0005]

However, in the image forming apparatus having the tension applying roll provided with the belt end guide member as described above, when the image is formed for a long period of time, the above-mentioned belt meandering phenomenon occurs. In addition to the image defect, the trouble (malfunction or the like) caused by the electrostatic action in the belt transporting device occurs even though the belt is being discharged, and the image defect is caused. Regarding the troubles caused by this electrostatic action, according to the study by the present inventors,
Insulating belts are not sufficiently neutralized, and electrical noise, etc., occurs due to the electric charge remaining or accumulated in the both end areas of the insulating belt that is not neutralized by the belt static eliminator. It has been confirmed that problems sometimes occur. Further, it has been confirmed that as the number of revolutions of the belt increases, the accumulation of electric charges also increases, and as a result, the level to be neutralized also increases with time.

A measure to improve the charge removal performance of the belt charge eliminator for removing the charge from the insulating belt for transferring the transfer material is conceivable. In this case, however, there is a new problem that leakage increases as the charge removal performance increases. It occurred and could not solve the above problems.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image forming apparatus capable of preventing a malfunction of the apparatus, which is caused by an electrostatic action in a belt conveying apparatus for conveying a transfer material, and an image defect.

[0008]

The present invention (the invention according to claim 1 ) is formed on an image carrier by being stretched and rotated between a plurality of rolls having at least a drive roll and a peeling part roll. A transfer material transfer dielectric belt that electrostatically adsorbs a transfer material that transfers a toner image and transfers the transfer material to a transfer position, and the transfer belt is placed in the belt tension area between the drive roll and the peeling part roll of the dielectric belt. In an image forming apparatus provided with one or a plurality of image carriers to be provided, it contacts a side end portion outside the image forming area in the width direction orthogonal to the traveling direction of the transfer material conveying dielectric belt. It is characterized in that the conductive guide member is grounded.

The present invention (the invention according to claim 2 ) is
A transfer material which is stretched and rotated between a plurality of rolls having at least a drive roll and a peeling part roll and electrostatically adsorbs a transfer material that transfers a toner image formed on an image carrier to a transfer position. Dielectric belt for conveyance, one or more image carriers arranged in the belt stretching region between the driving roll and the peeling roll of the dielectric belt, and the dielectric belt are destaticized. In an image forming apparatus provided with a belt charge eliminating means, the transfer material transporting dielectric belt advances between the transfer position of the image carrier disposed closest to the peeling section roll and the belt charge eliminating means. Guides that come into contact with the side edges outside the image forming area in the width direction orthogonal to the direction
The electric guide member is grounded.

In the latter invention, the belt charge removing means
To the front side of the transfer material suction position from the transfer material
Image formation in the width direction orthogonal to the traveling direction of the dielectric belt for automobiles
Members that come into contact with parts outside the area can be grounded.
It In this case, the member to be grounded is not particularly limited as long as it does not hinder the grounding, for example, a conductive guide member for elastically supporting the side end portion of the transfer material conveying dielectric belt, A roll member for stretching the belt and a belt cleaning member.

The image bearing member is composed of a photosensitive member or a dielectric member capable of forming a latent image and a toner image by an electrophotographic system or an electrostatic recording system, and its form is a drum shape or a belt shape. Either may be used. And
The image carrier is arranged in the belt tension area between the drive roll and the peeling roll of the transfer material conveying dielectric belt.

[0012]

[Function] The transfer material conveying dielectric belt is often charged due to the transfer material being electrostatically adsorbed, being electrostatically transferred, and being in contact with various belt-related parts. The belt charge removing unit removes charge from the image forming area of the belt, but does not remove charge from the other belt areas (both ends), and is in an environment where electric charges are likely to be accumulated due to rubbing with the roll or other contact parts. Therefore, grounding is applied to a member that comes into contact with such a dielectric belt to prevent accumulation of electric charges.

This grounding is performed prior to the main static elimination by the belt static elimination means (however, on the downstream side of the transfer position of the image bearing member in the vicinity of the peeling section roll), or in addition thereto after the main static elimination ( However, it is also performed on the front side of the transfer material suction position). Of these, the belt charge elimination performed prior to this charge eliminating step is more effectively charged than expected due to the peeling discharge that occurs in the peeling portion of the transfer material on the dielectric belt, so the charge accumulated due to this process is also effective. It can be reduced or eliminated.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings.

1 to 3 show an embodiment of the present invention. FIG. 1 is a schematic structural view showing a main part of a color image forming apparatus to which the present invention is applied, and FIG. 2 shows its conductive guide member. The figure which shows the whole structure of the tension provision insulating roll which has, FIG.
FIG. 3 is an enlarged view showing a configuration of a roll end portion of FIG. 2.

In FIG. 1, reference numeral 10 is a transfer material conveying dielectric belt. The dielectric belt 10 is made of a dielectric film such as a polyethylene terephthalate film or a polyvinylidene fluoride film and has a thickness of 50 to 150 μm.
It is an endless belt of a certain degree, and is stretched around a plurality of rolls such as a drive roll 11, a peeling part roll 12, a tension applying roll 13 and an idler roll 14, and is rotated in the arrow direction in the figure. Further, around the transfer material conveying belt 10, a suction charger 15 and a suction roll 16 for adsorbing the fed transfer material P on the belt, and the transfer material P are separated from the belt 10. Peeling charger 17
Also, the peeling claw 18, the fixing device 18 for fixing the unfixed toner image on the transfer material P, the belt static eliminator 20 for eliminating the charge on the belt 10, and the cleaning device 21 for removing the residual deposits on the belt 10. Etc. are provided.

Of the plurality of rolls supporting the dielectric belt 10, the tension applying roll 13 is at the position farthest from the drive roll 11, and the belt tension between the peeling section roll 12 and the belt static eliminator 20 is set. It is arranged at a position within the rack area. Details of the tension applying roll 13 will be described later.

Black, yellow, magenta, and cyan toner images are formed on the upper surface of the transfer material conveying dielectric belt 10 in the belt tension area between the drive roll 11 and the peeling portion roll 12, respectively. The four sets of image forming units K, Y, M, and C to be formed are closely arranged in this order. Each of the image forming units K, Y, M, and C includes a photosensitive drum 1 as an image carrier that rotates in the arrow direction,
A charger 2, a laser scanning type image exposure device 3, a developing device 4, a pre-transfer charger 5, a transfer device 6, a cleaning device 7, etc. are arranged around the photosensitive drum 1. In the figure, reference numeral 8 is a transfer baffle for pressing the conductive belt 10 to bring it into contact with the photosensitive drum 1, 9 when necessary.
Is a static eliminator before cleaning the photosensitive drum 1.

In this color image forming apparatus, a color image is formed as follows. That is,
In each of the image forming units K, Y, M, and C, the photoconductor drum 1 is uniformly charged by the charger 2, and then the image exposure device 3 performs image exposure of the document to form the image on the photoconductor drum. An electrostatic latent image is formed. Each of these electrostatic latent images is a developing device 4 containing toner of each color (k, y, m, c).
To develop a toner image of each color on each photoconductor drum 1. On the other hand, the transfer material contained in the paper feed tray is conveyed to the vicinity of the transfer material conveying dielectric belt 10 by a paper feeding means (not shown), and then the belt 10 is moved by the suction charger 15 and the suction roll 16. It is conveyed to a transfer position where it is electrostatically adsorbed on the top and comes into contact with the photosensitive drum 1. Then, each toner image formed on each of the photosensitive drums 1 is transferred while being subjected to the action of the transfer device 6 after being adjusted by the pre-transfer charging device 5 to an optimal charging state for transfer, if necessary. The transfer material P on the material conveying belt 10 is transferred so as to be sequentially superposed. Transfer material P after transfer is completed
Is peeled from the belt 10 by the peeling action of the peeling charger 17 and the peeling claw 18, is sent to the fixing device 19, is subjected to a fixing process, and is then discharged to the outside of the machine. As a result, a transfer material on which a color image is formed is obtained.

After the completion of the transfer process, each photoconductor drum 1 is cleaned by the cleaning device 7 and neutralized, and thereafter, the image forming process as described above is continuously repeated or for the next image forming process. stand by. On the other hand, the transfer material carrying belt 10 after the transfer material P has been peeled off is cleaned by the cleaning device 21 after being discharged by the charge remover 20.

2 and 3 are views showing the tension applying roll 13 described above. As shown in FIGS. 1 to 3, the tension applying roll 13 is composed of an insulating roll portion 30 and a conductive guide member 31 axially supported on both side portions of the insulating roll portion 30. The tension applying roll 13 is fixed to the apparatus (belt) frame via the tension applying mechanism 33, and thereby the tension applying roll 13 is rotationally driven with a proper tension to the transfer material conveying dielectric belt 10. It is designed to apply tension.

As shown in FIGS. 2 and 3, the insulating roll portion 30 has a rubber material (having a resistance value of 10 ¹²⁾ formed into a roll shape by providing a large number of slits 30a in the shape of a ring on the surface in the axial direction.
Ω or more) is attached to the shaft 34. From the viewpoint of more effectively suppressing the meandering phenomenon of the belt, the slit 30a spirally orbits from the left and right ends of the roll toward the center, and the left and right slits finally match at the center of the roll. It is formed in a slit pattern. The shaft 34 is rotatably supported by the tension applying arm 33 a of the tension applying mechanism 33 via a bearing 35, and the insulating roll portion 30 is also rotated integrally with the shaft 34. In this embodiment, the peeling section roll 12 and the roll section of the idler roll 14 are also configured in substantially the same manner as the insulating roll section 30 (however, the spiral pattern of the spiral pattern of the slits of both rolls 12 and 14 is in the circumferential direction). , From the viewpoint of more effectively suppressing the meandering phenomenon of the belt, the direction is opposite to that of the insulating roll portion 30).

On the other hand, the conductive guide member 31 is composed of a substantially cylindrical guide body 31a made of a resin molding and a metal guide portion 31b having an L-shaped cross section attached to the guide body. Shaft sliding portion 34a
Is rotatably supported in the axial direction at
A spring 36 interposed between the guide body 30a and the bearing 35 normally urges the guide body 30a in the direction of arrow P so as to abut the side end portion of the insulating roll portion 30. The conductive guide member 31 itself does not rotate, but is only movable in the axial direction.

In the tension applying roll 13, the conductive guide member 3 is in contact with the side end of the dielectric belt 10.
The first metal guide portion 31b is grounded. In addition, in this embodiment, as shown in FIG. 4, the peeling section roll 12 which is a component that comes into contact with the dielectric belt on the front side of the belt static eliminator 20 and the dielectric on the rear (downstream) side of the belt static eliminator 20. Conductive brush roll 21 of belt cleaning device 21, which is a part that comes into contact with the body belt
a, the cleaning blade 21b, the brush facing roll 21c, and the drive roll 11 are also grounded. Reference numeral 37 in the figure denotes a ground wire.

By the way, the transfer material carrying dielectric belt 10 is
While being appropriately tensioned by the tension applying roll 13, the drive roll 11 is rotated through each roll by the rotational driving force of the drive roll 11. Moreover, meandering traveling is controlled by the conductive guide member 31 of the tension applying roll 13 during this rotation. That is, since the side end of the belt 10 rotates while touching the metal guide portion 31b of the conductive guide member 31, the end portion of the belt 10 on the side of the belt is conductive guide member 31 due to unevenness or meandering of the edge. When is pressed (in the direction of arrow F in the figure), the guide member 31 moves in the axial direction while being biased by the spring 36, whereby the meandering is controlled. This meandering control effect is most efficiently exhibited because the tension applying roll 13 is disposed at the position farthest from the drive roll 11.

Also, the transfer material conveying dielectric belt 10
In general, a cycle of repeating electrostatic adsorption (conveyance) of a transfer material, transfer step at each transfer position, and peeling step in this order, and then a static elimination step by the belt static eliminator 20 to prepare for the next transfer material adsorption is repeated. While turning. Conventionally, the static elimination of the dielectric belt 10 is performed by the belt static eliminator 20.
The static electricity was being removed by. Further, as shown in FIG. 4, static elimination by the belt static eliminator 20 is performed only in a region corresponding to the maximum image forming (sheet holding and conveying) region S in the entire width region of the dielectric belt 10, and other than that. The belt area E is not performed. It is needless to say that the width (charging width) of the suction charging device 15, the transfer device 6, and the peeling charging device 17 is substantially equal to the maximum image forming area S.

On the other hand, in the apparatus of this embodiment, the dielectric belt 10 which has undergone the transfer process and the peeling process is first neutralized by the peeling part roll and the conductive guide member 31 of the tension applying roll 13, and thereafter, The static elimination by the belt static eliminator 20 is performed. As a result, the charged charges due to the peeling discharge generated between the transfer material and the belt, which are peeled off at the peeling portion, are efficiently removed. Furthermore, the belt static eliminator 2
Even after the static elimination by 0, the belt cleaning device 2
The first conductive brush roll 21a, the cleaning blade 21b, and the brush-opposing roll 21c perform static elimination, and the drive roll 11 performs final static elimination.

As a result, the entire area of the transfer material carrying dielectric belt 10 before the next transfer material is adsorbed can be efficiently and evenly discharged. Above all, the area (both ends) E outside the image area of the dielectric belt 10, which has not been conventionally performed, is surely discharged. Further, the side end portion (edge portion) of the dielectric belt 10 is also surely discharged by the conductive guide member 31 of the tension applying roll 13. Therefore, when an image is formed by the apparatus of this embodiment, it is possible to reliably prevent troubles such as a malfunction of the apparatus due to insufficient static elimination or uneven static elimination, and as a result, good image formation is stable. It becomes possible to do it.

[0029]

As described above, according to the present invention,
The charge is removed from the portion of the transfer material transporting dielectric belt outside the image forming region in the width direction, which has not been removed by the belt charge removing unit. Such static elimination is performed prior to the main static elimination step by the belt static elimination means,
In addition to this, since it is also performed after this static elimination step, it is possible to surely prevent the malfunction of the device, which is caused by the electrostatic action in the transfer material transporting belt transporting device, and eventually the image defect.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a main part of a color image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the overall configuration of the tension imparting insulating roll of FIG.

FIG. 3 is an enlarged cross-sectional view showing an enlarged configuration of a conductive guide member of the roll of FIG. 2 and its surroundings.

FIG. 4 is an explanatory diagram showing a width relationship between a dielectric belt and a member in contact with the dielectric belt and a grounding process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image carrier, 10 ... Dielectric belt for transferring transfer material, 11
... drive roll, 12 ... peeling section roll, 13 ... tension imparting insulating roll, 20 ... belt static eliminator, 31 ... conductive guide member, P ... transfer material, S ... image forming area, E ... area outside image forming area (Both ends).

Front page continued (72) Inventor Yukio Hayashi 2274 Hongo, Ebina City, Kanagawa Prefecture, Fuji Zerox Co., Ltd. (72) Inventor Junichiro Samejima, 2274 Hongo, Ebina City, Kanagawa Prefecture, Fuji Xerox Co., Ltd. Ryoichi 2274 Hongo, Ebina City, Kanagawa Prefecture, Fuji Xerox Co., Ltd. (56) Reference JP-A-7-56445 (JP, A) JP-A-5-216382 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/16 G03G 15/00 510

Claims (4)

(57) [Claims] 1. A transfer position by electrostatically adsorbing a transfer material which is stretched and rotated between a plurality of rolls having at least a drive roll and a peeling part roll and which transfers a toner image formed on an image carrier. A transfer material transporting dielectric belt, and one or a plurality of image carriers disposed in a belt stretching region between the driving roll and the peeling part roll of the dielectric belt. In the image forming apparatus, a conductive gas contacting a side end portion outside the image forming area in the width direction orthogonal to the traveling direction of the transfer material conveying dielectric belt.
An image forming apparatus in which an id member is grounded. 2. A transfer position by electrostatically adsorbing a transfer material which is stretched and rotated between a plurality of rolls having at least a drive roll and a peeling part roll to transfer a toner image formed on an image carrier. A transfer material transporting dielectric belt, one or a plurality of image carriers disposed in a belt stretching region between the driving roll and the peeling section roll of the dielectric belt, In an image forming apparatus provided with a belt charge removing unit for removing charge from the body belt, the transfer material is conveyed between the transfer position of the image carrier arranged closest to the peeling section roll and the belt charge removing unit. An image forming apparatus characterized in that a conductive guide member, which is in contact with a side end portion outside the image forming region in the width direction orthogonal to the traveling direction of the dielectric belt, is grounded. 3. A belt charge removing means is used to adjust the transfer material suction position.
How to move the dielectric belt for transferring the transfer material to the front side
Touches a part outside the image forming area in the width direction orthogonal to the direction
The image forming apparatus according to claim 2, wherein the member to be grounded is grounded . 4. The belt cleaning unit is a member to be grounded.
The image forming apparatus according to claim 3, which is a material .