JP3003085B2 - Transfer paper separation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a color copying machine, a facsimile, and a printer. More specifically, the present invention relates to an image forming apparatus for transferring a toner image on an image carrier from a sheet member whose surface moves endlessly. The present invention relates to a separation device for separating transfer paper.

[0002]

2. Description of the Related Art Conventionally, as a separation apparatus of this type, the transfer of a toner image from an image carrier to a transfer sheet held on a dielectric sheet whose surface moves endlessly by electrostatic attraction is completed. Thereafter, the electric charge causing the electrostatic attraction force is eliminated by a static eliminator, and the tip of the swingable separation claw is interposed between the dielectric sheet surface and the transfer paper to remove the transfer paper from the dielectric sheet. Is known (for example,
See JP-A-55-32079). In this transfer paper separating apparatus, the static elimination is performed by the static eliminator. However, the transfer paper having high insulation properties or the dielectric sheet formed of resin or the like cannot be completely eliminated, and the transfer paper has a dielectric material. There is a risk that poor separation may occur without adhering to the tip of the separation claw while adsorbed on the sheet.

Therefore, in order to further improve the separation performance of the transfer paper separating apparatus, the sheet after the charge elimination is moved along the path of the endless movement which can push up substantially the center in the width direction of the dielectric sheet. The push-up member disposed inside pushes up and deforms the vicinity of the tip of the separation claw, which is provided outside the endless movement path and swings so that the tip approaches the dielectric sheet, thereby deforming the separation claw. It is also known that the curvature of the sheet near the tip of the nail is increased to facilitate separation.

[0004]

However, according to this structure, the separation is improved, but only the portion corresponding to the center of the leading end of the transfer sheet of the dielectric sheet is deformed and separated, so that the transfer sheet after separation is separated. However, when the paper enters the fixing roller in the next fixing step, there is a problem that wrinkles and breaks occur in the deformed portion of the transfer paper. Further, there is also a problem that a device for separation is complicated, the number of operating members is large, and the cost is high.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a transfer paper which can perform good separation and does not cause wrinkling or folding of the transfer paper in a fixing step. To provide a separation device.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to an apparatus for holding a transfer paper on which a toner image has been transferred from an image carrier, and having at least a portion of which surface is endlessly moved. A transfer sheet separating device for separating the transfer sheet from the sheet member having the property, wherein the transfer sheet is disposed inside the endless movement path, and the transfer sheet in the width direction of the sheet member extends in the same direction.
A first member having a length capable of contacting the region, a second member disposed outside the path of the endless movement and downstream of the backup member in the direction of the endless movement, and Supporting means for movably supporting at least one member of the member and the second member to the side where the other member is disposed beyond the path of the endless movement, and driving the supporting means,
A drive means is provided for moving the one member together with the other member to a position where the one member comes into contact with the sheet member in a state of being shifted from each other in the direction of the endless movement . For example, the surface of the transfer paper held by electrostatic attraction force on a flexible dielectric sheet to move endlessly, after transfer of the toner image from the image bearing member is completed, the electrostatic attractive force In the transfer paper separating apparatus for removing the generated electric charges and deforming the sheet to separate the transfer paper from the sheet, the transfer paper is separated from the transfer position and the separation position outside the path of the endless movement. A static eliminator disposed in the vicinity of the tip of the separation claw, which is the second member and the support member, in a non-contact manner with the sheet; and the inside of the endless movement path, which is the first member. A backup roller disposed in non-contact with the sheet at a localization value facing the static eliminator, and the driving means, the transfer sheet, when the transfer sheet is separated, moves the sheet inside the path of the endless movement with the tip of the separation claw. And wrap it around the backup roller to deform it. Sea urchin, provided the pawl controlling unit, changing at least one of the position and orientation of the separation claw. The claw control means controls the separation claw during the transfer operation so that the backup roller and the sheet are not in contact with each other without pushing the sheet into the path of the endless movement at the tip thereof, and only during separation. It is preferable that the separation claw is controlled so that the sheet is brought into contact with the backup roller by pushing the sheet into the endless movement path at its tip. Further preferably, the claw control means pushes the separation claw into the path of the endless movement at the leading end thereof before the transfer paper on the sheet reaches the operation position of the static eliminator. The sheet is controlled so that the backup roller and the sheet come into contact with each other. Further, the backup roller is constituted by a grounded conductive roller, and at the time of separation, exhibits a counter electrode function of the static eliminator and is arranged at a position where the sheet is deformed into a shape in which the transfer paper can be easily separated therefrom. It is desirable to set up.

[0007]

According to the present invention, there is provided a first member which is disposed inside an endless movement of a sheet and has a predetermined length in the width direction of the sheet member when separating the transfer paper; A driving unit that supports at least one of the second members disposed outside the path and downstream of the first member in the direction of the endless movement is driven to drive the endless movement path. To the side on which the other member is disposed, thereby abutting the sheet member in a state of being shifted from each other in the direction of the endless movement, and having a predetermined length in the width direction of the sheet member. The sheet member is deformed while using the first member as a guide for deformation, thereby acting to facilitate separation of the transfer sheet from the sheet member without causing undesirable transfer paper wrinkling. Things.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a color electrophotographic apparatus as an image forming apparatus will be described below. FIG.
1 is a schematic configuration diagram of a color electrophotographic apparatus according to the present embodiment. Around the photosensitive drum 1 having a photoconductive layer on its surface, a charging corona discharger 2, an exposure optical system 3, a yellow developing device 4, a magenta developing device 5, A developing device 6, a black developing device 7, a transfer drum 8, a cleaning static eliminator 9, a cleaning device 10, and a photoreceptor static eliminator 11 are arranged respectively. The transfer drum 8, for example, as shown in FIG.
The drum body 12 is formed by cutting off an intermediate portion thereof while leaving both sides of the circumference and a band-shaped connecting portion continuous with the both sides, and a transparent dielectric sheet 13 covering the entire cut portion. Is described in detail in JP-B-63-34467. Such a transfer drum 8
Instead, as shown in FIG. 4 and FIG.
A transfer sheet supporting dielectric sheet 13 formed in an endless cylindrical shape may be attached therebetween. As shown in FIG. 1, a transfer corona discharger 14 is provided inside the transfer drum 8 at a portion facing the photoreceptor drum 1, a corona discharger 15 is provided at a lower portion thereof for adsorbing transfer paper, and a right upper portion is provided at a lower right portion thereof. Are provided with a corona discharger 16 for removing the transfer drum. At a position outside the transfer drum 8 opposite to the corona discharger 15 for absorbing the transfer paper, a conductive roller 17 that is provided so as to be able to contact and separate from the surface of the transfer drum 8 is arranged. At a position outside the transfer drum 8 that faces the transfer drum 16, a cleaning blade 18 that is provided so as to be able to contact and separate from the surface of the transfer drum 8 is arranged. Further, immediately above the cleaning blade 18, a separation claw 19 for separating the transfer paper is provided so as to be able to contact and separate from the surface of the transfer drum 8. Further, a corona discharger 20 for removing the transfer paper is provided on the left side. A backup roller 20a is fixedly disposed inside the transfer drum 8 facing the corona discharger 20 with a dielectric sheet interposed therebetween.

When the surface of the photoreceptor drum 1 is uniformly charged by the charger 2, a color image passing through a blue filter is irradiated by the exposure optical system 3, and the yellow component of the color image is mainly contained. A latent image is formed there. The latent image is developed by supplying a yellow developer which is a complementary color of blue from the developing device 4. The yellow image on the photosensitive drum obtained by the development is
The transfer paper 22 supplied from the printer 1 and adsorbed on the transfer drum 8 by the charger 15 and the roller 17 is overlapped at a position where the photosensitive drum 1 and the transfer drum 8 are in contact with each other, and the yellow image is transferred by the corona discharger 14. Transferred to paper. At this time, the transfer paper is more strongly attracted to the transfer drum 8 by the discharger 14. The rotations of the photosensitive drum 1 and the transfer drum 8 are synchronized, and the photosensitive drum 1 and the transfer drum 8 are driven such that the leading end of the image on the photosensitive drum coincides with the end of the transfer paper on the transfer drum 8. When the transfer paper 22 is completely absorbed by the transfer drum 8, the operation of the corona discharger 15 is stopped, and the roller 17 is separated from the surface of the transfer drum. In addition, separation claw 1
The cleaning blade 9 and the cleaning blade 18 are always separated from the surface of the transfer drum. Therefore, after the charge on the transfer paper surface is removed by the charge remover 20, the yellow image transferred onto the transfer paper is transferred to the next image transfer without being rubbed by the separation claw 19, the cleaning blade 18 and the roller 17. Welcome. On the other hand, on the photosensitive drum 1 side after the transfer of the yellow image, the charged potential of the yellow toner remaining on the surface is removed by the cleaning neutralizer 9, and then the residual toner is removed by the cleaning device 10. The residual potential on the surface of the photoconductor is removed by the neutralizer 11. Next, when the surface of the photosensitive member is uniformly charged again by the charger 2, the exposure optical system 3
Thus, a color image passing through the green filter is irradiated, and a latent image mainly composed of a magenta component of the color image is formed thereon. The latent image is developed by supplying a magenta developer which is a complementary color of green from the developing device 5 to obtain a magenta image. This magenta image is superimposed and transferred on the yellow image of the transfer paper on the transfer drum. In the same manner, a cyan image is obtained by image exposure using a red filter and development with a cyan developer which is a complementary color of red, and this is overlaid and transferred onto an already transferred image on transfer paper. Further, if necessary, an image is exposed by white light and a black image obtained by a black developer is overlaid and transferred. When the final image transfer is completed, the transfer paper on the transfer drum is separated from the surface of the transfer drum by the separation claw 19 and fixed by a fixing device (not shown). The transfer drum from which the transfer paper has been separated is neutralized by the neutralizer 16, and the developer adhered to the surface during transfer is removed by the cleaning blade 18.

Next, the transfer paper separating apparatus will be described in detail.
3 to 6, the backup roller 20a is made of a conductive material. This backup roller 20
a is a support bracket 12E fixedly attached to the fixed shaft 12c.
And has a length in the width direction that is wider than the width of the transfer paper 22 having the maximum width to be used and is equal to or slightly larger than the effective opening width of the charge removing charger 20. I have. And, this backup roller 20
a is a support bracket 12E, a fixed shaft 12 made of a conductive material.
C, is electrically grounded through the drum side plate 12d and the main body. Also, the backup roller 20a and the dielectric sheet 1
3, a gap 20G is formed as shown in FIG. The size of the gap 20G is set to a predetermined distance so that the charges on the surface of the dielectric sheet 13 during the transfer operation are not moved or disturbed. One or more separation claws 19 are provided across the transfer material moving direction. Separating nail piece 19
The base end of C is rotatably supported by a shaft 19b perpendicular to the plane of the drawing, and a rotor 19a is rotatably attached to the free end of the shaft 19b about a plane perpendicular to the plane of the drawing. And this axis 19
b is rotationally driven by a solenoid or the like controlled by a control signal from a control unit (not shown).

In the above configuration, during the transfer operation, as shown in FIG. 6, the separation claw 19 is electrostatically attracted and conveyed to the dielectric sheet 13 so as not to hit the transfer paper 22. Thus, the transfer operation is performed without deforming the dielectric sheet 13 and keeping the gap 20G with the backup roller 20a. When the transfer operation is completed, FIG.
As shown in (2), the separation claw 19 moves in the counterclockwise direction and rotates to separate the leading end of the transfer paper 22 from the transfer paper support sheet 13. As an operation sequence for this, first, before the leading end of the transfer paper 22 reaches the operation position of the corona discharger 20, the separation claw 19 is rotated to the position shown in FIG. This is because the effect of the corona discharger 20 is further improved by the close contact between the backup roller 20a and the dielectric sheet 13. The backup roller 20a is also effective for forming a large curvature for separating the dielectric sheet 13 and the transfer paper 22 that are in close contact by electrostatic attraction, since the backup roller 20a is a small diameter roller. In this way, the backup roller 20a is opposed to the corona discharger 20, and is separated from the dielectric sheet 13 during the transfer operation. The dielectric sheet 13 is brought into close contact with 19, whereby the dielectric sheet 13 is deformed into a large curvature and separated. The separating claw 19 is rotated clockwise immediately after the end of the separating operation, and
It returns to the state of.

In the above embodiment, the dielectric sheet 2
2 to facilitate the separation of the transfer paper 22 from the transfer paper 22.
Is deformed while the backup roller 20 is deformed while abutting on the entire area of the transfer paper 22 in the width direction.
Wrinkles and the like parallel to the transport direction are not generated on the transfer paper 22, and it is possible to prevent wrinkles and breaks from occurring in the deformed portions of the transfer paper when entering the fixing roller in the fixing process. Unlike this embodiment , if the deformation is to be caused by simply pushing the dielectric sheet 22 at the tip of the separation claw 19 without providing the backup roller 20, the dielectric sheet 13 extends over a relatively large area of the dielectric sheet 13. by only it results in a gradual deformation Te, it is difficult to obtain a separation on sufficient curvature. During the transfer operation, the corona discharger 20 is turned off.
And a backup roller 20a as a counter electrode
Also, since the nail 19 is sufficiently separated from the dielectric sheet 13 and the paper 22, a clear transfer image is obtained without rubbing the image and uneven transfer due to disturbance of the electric field due to the influence of frictional charge and discharge. Further, the backup roller 20a also serves as a guide for increasing the curvature of the dielectric sheet 13 in order to separate the transfer paper 22 from the function as the counter electrode of the corona discharger 20, so that each function is provided as a separate member. The number of parts can be reduced as compared with the case of having. It is only the separation claw 19 that needs to be moved or changed in posture to deform the dielectric sheet 13, and the backup roller 20 a is used to move the dielectric sheet 13 into and out of contact with the dielectric sheet 13 as in a conventional push-up member. Since no swinging is required, vibration can be prevented and the structure can be simplified.

In the above-described embodiment, the backup roller 20a is fixed at a fixed position and the rotation of the separation claw 19 is controlled.
3 and a backup roller 20a is supported so as to be able to move in parallel in a direction perpendicular to the surface of the dielectric sheet 13, for example. To deform the dielectric sheet 13. Also in this case, since the dielectric sheet 13 is guided by the backup roller 20a in the width direction, it is possible to prevent undesired wrinkles or the like from occurring on the transfer paper.

According to the first aspect of the present invention, the sheet member holding the transfer paper is deformed while using the first member having a predetermined length in the width direction as a guide at the time of deformation,
This facilitates separation of the transfer paper from the sheet member without causing undesirable transfer paper wrinkles, so that when the separated transfer paper enters the fixing roller in the next fixing step, the transfer paper is transferred. There is an excellent effect that wrinkles and folds can be prevented from occurring on the paper.
According to the second aspect of the present invention, the flexible dielectric sheet is wound around the fixedly disposed backup roller by controlling the separation claw by the claw control means, thereby deforming the sheet. Since only the separation claw is required to change the position and the posture in order to deform the sheet, the structure of the device used for separation can be simplified. Further, according to the third aspect of the present invention, the separation claw during the transfer operation is controlled so that the backup roller and the sheet are not in contact with each other without pushing the sheet into the path of the endless movement at the tip thereof. Therefore, when the backup roller comes into contact with the sheet during the transfer operation,
It is possible to prevent problems such as image rubbing.
Further, according to the invention according to claim 4, the backup roller is constituted by a grounded conductive roller, and at the time of separation, exhibits the counter electrode function of the static eliminator and separates the sheet from the transfer paper. Since the sheet is arranged at a position where the sheet is easily deformed, the function as a counter electrode of the removing machine and the function as a guide when the sheet is deformed can be combined, and the number of parts can be reduced. Further, according to the fifth aspect of the invention, before the transfer paper on the sheet reaches the operation position of the static eliminator, the separation claw is pushed into the path of the endless movement by the leading end of the separation claw. Since the backup roller and the sheet are controlled so as to be in contact with each other, the leading end of the transfer sheet can be satisfactorily removed, and the transfer sheet can be reliably separated.

[Brief description of the drawings]

FIG. 1 is a front view showing a schematic configuration of a color electrophotographic apparatus according to an embodiment.

FIG. 2 is a perspective view showing an example of a transfer drum 8 in FIG.

FIG. 3 is a front view showing a state of the transfer drama 8 during a separating operation.

FIG. 4 is a longitudinal sectional view showing another example of the transfer drum 8 in FIG.

5 (a) shows a part of the transfer drum 8 of FIG. 4, and FIG. 5 (b) is a perspective view of a dielectric sheet 22 in FIG.

FIG. 6 is a front view showing a state of a transfer drama 8 during a transfer operation.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor drum 8 transfer drum 13 dielectric sheet for supporting transfer paper 16 corona discharger for removing transfer drum 19 separation claw for removing transfer paper 20 corona discharger for removing transfer paper 20a backup roller 22 transfer paper

Claims (5)

(57) [Claims] 1. A transfer sheet separating apparatus for holding a transfer sheet onto which a toner image has been transferred from an image bearing member and separating the transfer sheet from a sheet member having at least a part of which has an endlessly movable surface. A first member disposed inside the endless movement path and having a length capable of contacting the entire area of the transfer sheet in the width direction of the sheet member in the same direction; and a first member outside the endless movement path. A second member disposed downstream of the first member in the direction of the endless movement; and at least one of the first member and the second member through the endless movement path. A supporting means for movably supporting the other member to the side where the other member is disposed, and driving the supporting means to displace the one member together with the other member in the direction of the endless movement. And a driving means for moving the sheet member to a position where it comes into contact with the sheet member. A transfer paper separating device characterized by the above-mentioned. 2. After the transfer of a toner image from an image carrier onto a transfer sheet held on a flexible dielectric sheet whose surface moves endlessly by electrostatic attraction force, the electrostatic attraction is performed. In a transfer paper separating apparatus for removing a charge causing a force and deforming the sheet to separate the transfer paper from the sheet, an outside of the path of the endless movement between the transfer position and the separation position A static eliminator disposed near the tip of the separation claw in a non-contact manner with the sheet; and a static value inside the endless movement path and opposed to the static eliminator. The backup roller provided is provided. When the transfer paper is separated, the position and orientation of the separation claw are pushed so that the sheet is pushed inside the endless movement path by the tip of the separation claw and wound around the backup roller to be deformed. Claw control means for changing at least one of the Transfer paper separating apparatus characterized by comprising. 3. The claw control means controls the separation claw during the transfer operation so that the backup roller and the sheet do not come into contact with each other without pushing the sheet into the endless movement path at its tip. And only when separating,
3. The transfer paper separating apparatus according to claim 2, wherein the leading end pushes the sheet inside the path of the endless movement to control the backup roller to contact the sheet. 4. The backup roller is constituted by a grounded conductive roller, and at the time of separation, exhibits a counter electrode function of the static eliminator and deforms the sheet into a shape from which transfer paper can be easily separated. transfer paper separating device according to claim 2, characterized in that it is disposed at a position. 5. The claw control means presses the separation claw at the leading end of the sheet into the endless movement path before the transfer paper on the sheet reaches the operation position of the static eliminator. The control device controls the backup roller and the sheet to be in contact with each other.
5. The transfer paper separating apparatus according to 2, 3 or 4 .