JP2003091163A - Image forming device - Google Patents

Abstract

(57) [Problem] To transfer a toner image on an image recording medium (photoreceptor) to an intermediate transfer medium pressed against the image recording medium with a strong load;
In a transfer method in which a paper image is formed by pressing the transferred image together with the paper with a strong load, the paper is prevented from adhering to the surface of the intermediate transfer medium to prevent conveyance errors such as paper jams and jams. SOLUTION: In the vicinity of a contact portion between an intermediate transfer medium and a pressure roller, the surface has a sheet adsorbing property, the conveyance direction is changed by deformation of a rubber layer of the intermediate transfer medium, or a shear force is applied to the sheet to deflect the warp. A peeling roller to be generated is provided.
As a result, the sheet can be reliably separated from the intermediate transfer medium.

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 including an image recording medium (photoreceptor) for forming an image in an image forming apparatus and an intermediate transfer medium for transferring an image onto a sheet.

[0002]

2. Description of the Related Art There are various conventional image forming methods for forming a color image on a recording medium for image formation such as paper. For example, an electrostatic image (photosensitive image) is formed on a photosensitive drum (photoreceptor). There is an electrophotographic system in which an electrostatic latent image is formed and then visualized with toner and then transferred to a sheet.

In the printer using the electrophotographic system,
There are a method of forming a color image on the surface of a photoconductor by multiple exposure and transferring it to a sheet at once, or a method of sequentially superposing a single color image on the sheet. However, in any of the electrophotographic methods, the image forming process using dry toner is the mainstream, and in this method, the toner particle size is large (7 to
(13 μm) and the toner before heat fixing has poor translucency, so it becomes a shade for the irradiation light of the second and subsequent colors and an electrostatic latent image is not sufficiently formed, so that a high quality color image can be obtained. There wasn't.

Therefore, a method capable of achieving both high-speed image formation and high-quality image formation is an electrophotographic method using a liquid developer, and its value is being reviewed in recent years. One of the merits is that it is possible to use toner with a particle size of submicron size. When using this liquid developer,
The problem of multiple exposure with dry toner as described above is solved. Furthermore, a sufficient amount of image density can be obtained with a small amount of toner, which is economical, and a texture equivalent to that of printing can be realized. Further, it is possible to save energy because it can be fixed on a sheet at a relatively low temperature.

In the color image formation by the multiple exposure described above, a color image is formed on the surface of the photoconductor, the color image is brought into contact with the photoconductor and transferred to an intermediate transfer medium having the surface formed of a rubber layer, and thereafter, The step of transferring the color image on the surface of the intermediate transfer medium to the conveyed paper is taken. In such a color image formation, in order to stably transfer the toner image from the intermediate transfer medium to various recording media, the surface of the intermediate transfer medium is heated to semi-melt the toner so that the transferability to the recording medium is improved. It is increasing.

However, since the adhesiveness of the toner increases, the toner sandwiched between the intermediate transfer medium and the sheet functions as an adhesive material. For this reason, depending on the paper, the paper may be stuck to the surface of the intermediate transfer medium after passing through the contact portion with the pressure roller, and may be wound around the intermediate transfer medium without being guided to the regular transport path or cause a transport error. There are cases. In particular, the case where the toner area in the image is high is remarkable, and when a solid image or the like is recorded on the leading end of the image recording medium in the transport direction, paper jam may be frequently caused. Therefore, a mechanism for separating the recording medium from the intermediate transfer medium is needed.

On the other hand, there are several methods for peeling the paper from the fixing roller, and the most common technique is the separation technique using a peeling claw. In this method, a plurality of wedge-shaped peeling claws are installed in the axial direction of the fixing roller, and the paper is peeled off from the fixing roller. In this case, in order for the peeling claw to surely peel the sheet, the tip of the peeling claw is brought into contact with the fixing roller at a predetermined angle so that the sheet is inserted between the sheet and the fixing roller.

This technique is very effective for a roller whose surface state does not change even when the peeling claw comes into contact with it. For example, the dry toner fixing roller is composed of a heat roll having a heater for heating inside an aluminum pipe, and a pressure roller made of silicon rubber or the like which opposes the heat roll. Since the toner image comes into contact with the heat roller, the paper may adhere to the surface of the heat roller depending on the conditions, but the paper can be reliably separated by keeping the peeling claw in contact with the heat roller. Become. As mentioned above, the heat roller consists of an aluminum tube, and since the surface releasability increasing member such as an extremely thin PTFE tube is provided on the surface, the surface texture changes even if the peeling claw comes into contact. Almost never.

[0009]

However, in color image formation by multiple exposure, the intermediate transfer medium is provided as described above, and the surface of the intermediate transfer medium is 0.5 to several meters.
A rubber layer of about m is provided. Therefore, the rubber layer may be broken or peeled off by bringing the peeling claw into contact with the surface of the intermediate transfer medium, and bringing the peeling claw into contact is not realistic.

Further, by reducing the curvature of the intermediate transfer medium and the pressure roller, the peeling method utilizing the restoring force due to the bending rigidity of the paper and the method of applying a release material such as silicone oil to the surface have been conventionally used. It is included in the technology.

If the former peeling technique is applied to a wet electrophotographic image forming apparatus and the diameters of the intermediate transfer roller and the pressure roller are reduced, the intermediate transfer roller and the pressure roller are each pressed by several tens of kilograms. Since the rollers are designed to come into contact with each other due to pressure, bending occurs in each roller, and uniform contact between the rollers cannot be maintained, resulting in defective transfer and eventually deterioration of image quality. For this reason, each roller needs to be a roller having a predetermined diameter, and it is difficult to apply the peeling technique using the waist of the paper.

Further, in the latter method of applying a release agent such as silicone oil, deterioration of development due to oil adhered to the photosensitive member,
Since it causes troubles such as complicated installation of the oil supply device and difficulty in matching conditions satisfying both transferability from the photoconductor and transferability to the paper, it is also unrealizable. In conclusion, it is difficult to apply the conventional peeling technology to the wet electrophotographic image forming apparatus,
There is no way to effectively separate the paper from the intermediate transfer medium,
There is a problem that troubles such as paper jams frequently occur.

The present invention has been made in order to solve the above-mentioned conventional problems, and its object is to reliably separate a recording medium such as a paper from an intermediate transfer medium, and to wrap the paper or jam the paper. An object of the present invention is to provide an image forming apparatus that does not have the above trouble.

[0014]

In order to achieve the above object, the first feature of the present invention is that an image recording medium on which a toner image is formed, and an image recording medium formed so as to face the image recording medium. An intermediate transfer medium having an elastic surface layer on which the toner image is transferred, and a recording medium (corresponding to the sheet 9 of the embodiment) that is pressed against the intermediate transfer medium and supplied to the pressed portion are conveyed to carry out the intermediate process. A pressure roller that transfers the toner image on the surface of the transfer medium to the recording medium, and an elastic surface layer that is in pressure contact with the intermediate transfer medium via the recording medium on which the toner image is transferred and that has a concave portion are formed. And a peeling member (corresponding to the peeling rollers 50, 70, 80 and the cleaning roller 60 of the embodiment).

A second feature of the present invention is an intermediate transfer having an image recording medium on which a toner image is formed and an elastic surface layer formed so as to face the image recording medium and to which the toner image is transferred. A medium, a pressure roller that is brought into pressure contact with the intermediate transfer medium, conveys the recording medium supplied to the pressure contact portion and transfers the toner image on the surface of the intermediate transfer medium to the recording medium, and the intermediate transfer medium. And a peeling member that is arranged so as to contact the conveyed recording medium and has an adhesive layer on the surface.

A third feature of the present invention is an intermediate transfer having an image recording medium on which a toner image is formed, and an elastic surface layer formed to face the image recording medium and to which the toner image is transferred. A medium, a pressure roller that is brought into pressure contact with the intermediate transfer medium, conveys the recording medium supplied to the pressure contact portion, and transfers the toner image on the surface of the intermediate transfer medium to the recording medium; And a rigid peeling roller having a small curvature and pressed against the intermediate transfer medium via the recording medium on which the toner image is transferred.

A fourth feature of the present invention is to have an image recording medium on the surface of which a toner image is formed, and an elastic surface layer formed so as to face the image recording medium and to which the toner image is transferred. An intermediate transfer medium having a first rotation direction and a recording medium that is brought into pressure contact with the intermediate transfer medium and is supplied to the pressure contact portion to convey the toner image on the surface of the intermediate transfer medium to the recording medium; A pressure roller having a rotation direction different from the first rotation direction, and a peeling roller which is pressed against the intermediate transfer medium via the recording medium on which the toner image is transferred and rotates in the first rotation direction. It is to have.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration according to a first embodiment of an image forming apparatus of the present invention, and a wet electrophotographic image forming apparatus will be described as an example.

In the image forming apparatus of this example, an image recording medium (photosensitive drum) 1 is arranged at the center, and a charger 2 for forming a yellow (Y) image on the surface of the image recording medium 1 is arranged around the image recording medium 1. -1, a developing device 4-1 are arranged, then a charging device 2-2 for forming a magenta (M) image on the surface of the image recording medium 1 and a developing device 4-2 are arranged, and then cyan. A charging device 2-3 and a developing device 4-3 for forming the image of (C) on the surface of the image recording medium 1 are arranged, and then a black (B) image is formed on the surface of the image recording medium 1. A charging device 2-4 and a developing device 4-4 for
-4 is a drying nozzle 30 on the downstream side in the traveling direction of the image recording medium.
Are arranged in order. An intermediate transfer medium 6 is in contact with the image recording medium 1, and a pressure roller 7 is in pressure contact with the intermediate transfer medium 6. A peeling roller 50 and a guide member 51 are arranged in the vicinity of the contact portion between the intermediate transfer medium 6 and the pressure roller 7, and the cleaning roller 15 is in contact with the intermediate transfer medium 6. Further, a cleaner 8 for cleaning the surface of the image recording medium 1 is arranged between the intermediate transfer medium 6 and the charger 2-1. The intermediate transfer medium 6 and the pressure roller 7 constitute the transfer device 5.

Here, the image recording medium 1 is a photosensitive drum in which an organic or amorphous silicon photosensitive layer is provided on a conductive substrate. The image recording medium 1 is uniformly charged by a well-known corona charger or scorotron charger 2-1 and then exposed by an image-modulated laser beam 3-1 to form an electrostatic latent image on the surface. It

Laser beam 3 for forming an electrostatic latent image
-1, 3-2, 3-3 and 3-4 scan the surface of the image recording medium 1 in a direction orthogonal to the rotation direction by rotating the polygon mirror 10 formed of a polyhedral mirror at a high speed by the polygon motor 11. Further, each beam is emitted from an independent semiconductor laser light source (not shown), is deflected on the same surface of the polygon mirror 10, is narrowed down to a minute spot of about 0.06 mm on the drum surface, and image recording is performed. In the surface scanning of the medium 1, the fθ lens 1 for keeping the scanning speed constant in the axial direction of the photosensitive drum.
After passing through 2 and 13, folding mirror assembly 20-1 to 20-1
Lights are respectively distributed to prescribed positions on the surface of the image recording medium 1 by 20-8. While scanning the surface of the image recording medium 1, each laser beam 3-1 is adjusted according to the image information to be formed.
A necessary electrostatic latent image is formed by controlling blinking of 3-4.

Thereafter, the electrostatic latent image is visualized by the developing device 4-1 containing the liquid developer. In the development process, a few% of carrier liquid consisting of insulating liquid
The liquid developer containing the toner solid content is supplied between the photoconductor, which is the image recording medium 1, and the developing roller to which the bias voltage is applied, and the toner adheres to the electrostatic latent image portion by the principle of electrophoresis to cause the toner. Image development is performed. In order to collect the excess carrier liquid from the developed toner image and more firmly attach the toner to the surface of the image recording medium 1, the downstream side of the developing roller 41 of the developing device 4-1 in the moving direction of the image recording medium, A squeeze roller 42, which is opposed to the image recording medium with a narrow interval and has a surface traveling direction different from that of the image recording medium 1, is provided.

The liquid developer adhering to the electrostatic latent image may be directly transferred to the transfer step and transferred to the sheet 9 by the transfer device 5, but here, the second charger 2-2 and the second charger 2 are continued. After the second electrostatic latent image is formed by the exposure of the laser 3-2, the second developer containing the second developer of a color different from the liquid developer stored in the first developing device 4-1 is formed. Developing device 4-
This is developed by 2. Therefore, after the second development, two color toner images are formed on the image recording medium 1. Similarly, the third and fourth developments are performed, and a full-color toner image is formed on the image recording medium 1. In this example, yellow (Y), magenta (M), cyan (C), and black (K) liquid developers are stored in order in the first to fourth developing units 4-1 to 4-4. ing.

The toner image is transferred to the sheet 9 by the transfer device 5.
However, in this example, as shown in FIG. 1, the method of transferring to the paper 9 via the intermediate transfer medium 6 is adopted. In this method, a drying nozzle 30 is provided to supply blowing air for removing the carrier liquid from the full-color toner image formed on the image recording medium 1. The toner image from which the carrier liquid has been removed is transferred onto the surface of the intermediate transfer medium 6 which is in contact with the image recording medium 1. The intermediate transfer medium 6 has a cleaning roller 15 for removing dirt from its surface.
Are always in contact with each other and are driven by the intermediate transfer medium 6. However, the cleaning roller 15 does not necessarily have to be attached.

The transfer from the image recording medium 1 to the intermediate transfer medium 6 and the transfer from the intermediate transfer medium 6 to the sheet 9 depend on the difference in surface energy between the two, that is, the difference in the adhesive force to the toner. When the toner image enters the nip portion (contact portion) between the image recording medium 1 and the intermediate transfer medium 6 that is in pressure contact, pressure is applied to the toner image portion and an adhesive force with the intermediate transfer medium 6 is generated. The adhesive force between the intermediate transfer medium 6 and the toner exceeds the holding force between the toner and the image recording medium 1, and the toner image is transferred to the intermediate transfer medium 6.

In the present example, the intermediate transfer medium 6 comprises a surface of a cylindrical aluminum tube having a base rubber layer of about 0.5 mm and a thickness of 0.2 mm.
It is configured to have a silicone rubber surface layer having a certain thickness. Further, a heat lamp composed of a halogen lamp is provided inside, and the surface of the intermediate transfer medium 6 is about 80
It is heated to the right degree.

The toner image transferred from the image recording medium 1 to the surface of the intermediate transfer medium 6 is heated from the surface of the intermediate transfer medium 6 and transitions to a semi-molten state by exceeding the glass transition temperature of the resin forming the toner. . This toner image then advances to the pressure contact portion with the pressure roller 7 which is in pressure contact with the intermediate transfer medium 6 with a linear pressure of about 1 to 4 kg / cm.

At this time, the paper 9 is supplied to the pressure contact portion by a paper feeding / conveying means (not shown), and the supplied paper is conveyed by the rotation of the intermediate transfer medium and the pressure roller, and also the intermediate transfer medium 6 and the pressure are applied. Depending on the pressure between the rollers 7,
The toner image on the surface of the intermediate transfer medium 6 is transferred due to the adhesive force generated on the sheet 9. At that time, the intermediate transfer medium 6
The sheet 9 after the image transfer is peeled off from the intermediate transfer medium 6 by the peeling roller 50 arranged in the vicinity of. Further, a guide member 51 is provided for guiding the sheet 9 once peeled to the regular transfer path so that the sheet 9 is not wound around the intermediate transfer medium 6 again.

In the image forming apparatus of this embodiment, since the transfer is performed regardless of the type of paper, the intermediate transfer medium 6
Is heated, and the pressure roller 7 is brought into pressure contact with a strong pressing force. For this reason, the toner image, which has transitioned to the semi-melted state by heating, functions as an adhesive, so that the sheet 9 is attached to the intermediate transfer medium 6. Therefore, without the peeling roller 50, the paper 9 may not be peeled from the intermediate transfer medium 6 even after passing through the contact portion with the pressure roller 7.

Next, the structure of the peeling roller 50 which is a paper peeling member, which is a characteristic part of this embodiment, will be described with reference to FIG. FIG. 2 is a perspective view showing a detailed configuration of the peeling roller 50 described above. As shown in FIG. 2A, the peeling roller 50 is located near the contact portion between the intermediate transfer medium 6 and the pressure roller 7,
The sheet 9 is arranged on the downstream side in the transport direction.

The length of the peeling roller 50 of this example is smaller than the width of the paper, and the metal shaft 52 is provided with two metal shafts 52 so that the peeling roller 50 and the back surface of the paper 9 contact each other at two positions in the paper width direction.
A peeling roller 50 is installed at the location. The metal shaft 52 is held by bearings (not shown) and is rotatable.

The peeling roller 50 is composed of a rubber layer having a rubber hardness of about 30 to 50, and has a plurality of concave portions 55 on the surface as shown in FIG. 2B. The recess 55 is a spherical recess having a diameter of about 4 mm and a depth of about 3 mm, and is formed by providing a protrusion for forming a recess on the inner surface of the mold when the peeling roller 50 is molded.

The peeling roller 50 has a diameter of about 30 mm and is in contact with the intermediate transfer medium 6 with a pressing force of about 5 kg. Therefore, the contact portion is deformed following the shape of the intermediate transfer medium 6.

Next, the peeling operation of the sheet 9 by the peeling roller 50 will be described with reference to FIG. However, in order to simplify the description, FIG. 3 shows a paper peeling mechanism in the case where one recess 55 is provided on the surface of the peeling roller 50. When the concave portion 55 provided on the surface of the peeling roller 50 advances to the nip portion (contact portion between the pressure roller 7 and the intermediate transfer medium 6) (FIG. 3A), the concave portion 5 is deformed due to the deformation of the roller 50.
5 also transforms. At this time, since the volume of the concave portion 55 is deformed so as to be reduced, the air inside is pushed out. At this time, it is assumed that the paper 9 advances to the contact portion between the roller 50 and the intermediate transfer medium 6 and is in contact with the concave portion 55 ((2) and (3) in FIG. 3).

Further, as the rotation of the intermediate transfer medium 6 progresses and the concave portion 55 comes out of the contact portion, the deformation is released,
Since the original shape of the recess is to be restored, the internal volume of the recess 55 increases. However, since the recess 55 is in contact with the paper 9, air is prevented from entering, and the inside becomes a negative pressure to adsorb the paper 9 (FIG. 3 (4)). This attracting force is larger than the force of adhering the intermediate transfer medium 6 and the sheet 9 by melting the toner, and the sheet 9 is peeled off without winding around the intermediate transfer medium 6.

On the other hand, since the peeling roller 50 has a small curvature, the peeling roller 50 is disengaged due to the bending rigidity of the sheet 9 and the concave portion 5 is in a negative pressure state.
Air gradually enters the sheet 5 and the suction force decreases, so that the sheet 9 is peeled off from the peeling roller 50. In this example, a wedge-shaped guide member 51 is provided in the vicinity of the contact portion between the peeling roller 50 and the intermediate transfer medium 6 to prevent reattachment of the sheet 9 to the intermediate transfer medium 6 and to accurately guide the sheet conveyance. .

According to this embodiment, in order to reliably form a toner image on a wide variety of image transfer media 6, the surface of the intermediate transfer medium 6 is heated to bring the transferred toner into a semi-melted state. Even if the toner image is transferred to the paper 9 between the pressure roller 7 and the pressure roller 7, the peeling roller 50 having a simple structure having the concave portion 55 on the surface is provided, so that the paper 9 can be transferred to the intermediate transfer medium with extremely high reliability. 6 can be peeled off. As a result, the conveyance of the sheet 9 in the image forming apparatus can be extremely stabilized, and troubles such as sheet jam can be eliminated and the reliability of the apparatus can be improved. Further, when the sheet 9 is peeled by the peeling roller 50, the peeling roller 50 is a rubber layer having a rubber hardness of about 30 to 50, so that the surface of the intermediate transfer medium 6 is prevented from being damaged or destroyed. You can Further, when the peeling roller 50 having the structure in which the concave portion 55 of the present example sucks the paper 9 is used, the certainty of peeling the paper is higher than when the peeling roller of another embodiment described below is used.

In the present embodiment, the recess 55 is realized by a hemispherical recess, but it can be realized by a horizontally long groove-shaped recess or an elliptical recess, and it is obvious that the same effect can be obtained.

FIG. 4 is a view showing the structure of a paper peeling member according to the second embodiment of the image forming apparatus of the present invention. However, the same parts as those of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description common to the first embodiment relating to image formation is omitted, and only the differences will be described.

The peeling roller 60 of this embodiment is arranged so as to be in contact with the intermediate transfer medium 6 and rotate at all times, and has a function of peeling the paper and a function of cleaning the surface of the intermediate transfer medium 6. Therefore, the peeling roller 60 is hereinafter referred to as a cleaning roller.

The cleaning roller 60 is a roller whose surface is composed of an adhesive silicone rubber layer, and uses the adhesiveness of the transfer residual toner adhering to the surface of the intermediate transfer medium 6 and the paper dust of the paper 9 by utilizing its adhesiveness. It is removed from the surface of the intermediate transfer medium 6.

A cleaning roller 60, which is longer than the image width formed on the intermediate transfer medium 6, is mounted on a rotatable metal shaft 52 supported by a bearing (not shown), and is moved by the surface of the intermediate transfer medium 6 or the conveyance force of the sheet 9. Rotate.

At this time, the cleaning roller 60 is disposed in the vicinity of the contact portion between the intermediate transfer medium 6 and the pressure roller 7, and the paper 9
Passes through the nip portion between the cleaning roller 60 and the intermediate transfer medium 6. Since the cleaning roller 60 has adhesiveness on the surface, the sheet 9 adheres to the surface of the cleaning roller 60 when the back surface of the sheet 9 comes into contact with the sheet 9 and is peeled off from the intermediate transfer medium 6.

The adhesiveness of the surface of the cleaning roller 60 is adjusted so that it has an adhesiveness necessary for removing dirt on the surface of the intermediate transfer medium 6 and an adhesiveness necessary for peeling the paper 9. You have to be sexual.

As with the peeling roller 50 of the first embodiment, the cleaning roller 60 has a curvature sufficiently small so that the paper 9 does not wind up, so that the cleaning roller 60 once adsorbs onto the surface of the cleaning roller 60. As the sheet 9 advances, it is detached by its waist. Also in this example, a wedge-shaped guide member 51 is provided to prevent the re-adhesion of the once peeled sheet to the intermediate transfer medium 6 so that the sheet 9 can be conveyed properly. When the surface of the cleaning roller 60 is soiled by toner or paper dust and the adhesiveness of the surface is reduced, the cleaning roller 60 is replaced.

According to the present embodiment, even if the cleaning roller 60 having an adhesive surface is used, the intermediate transfer medium 6
The sheet 9 can be reliably separated from the intermediate transfer medium 6 without damaging the surface of the sheet. Moreover, since it also serves to clean the surface of the intermediate transfer medium 6, it is possible to eliminate the need to separately install a new roller dedicated to peeling the paper.

In addition to the above-described structure, the cleaning roller 60 has, for example, a metal roller whose surface is coated with a resin having substantially the same properties as the toner resin, and a heating device is provided inside the cleaning roller 60 to make the surface resin layer sticky. The same effect can be obtained even with the roller having the structure.

FIG. 5 is a view showing the arrangement of a paper peeling member according to the third embodiment of the image forming apparatus of the present invention. However, the same parts as those in the first embodiment shown in FIG. 1 are designated by the same reference numerals, and the description common to the first embodiment relating to image formation is omitted, and only different points will be described.

The peeling roller 70 of this embodiment is composed of a metal roller having a diameter (8 mm in this embodiment) sufficiently smaller than the diameter (about 100 mm) of the pressure roller 7 and the intermediate transfer medium 6. The peeling roller 70 is provided at two positions in the paper width direction so as to be pressed against the surface of the intermediate transfer medium 6 with a strong pressing force, and is fixed to a metal shaft 52 rotatably supported by a bearing (not shown).

Next, the operation of this embodiment will be described.
Since the peeling roller 70 is pressed against the surface of the intermediate transfer medium 6 with a strong pressing force as described above, the surface of the peeling roller 70 is pressed into the rubber layer of the intermediate transfer medium 6 as shown in FIG.

As a result, the sheet 9 is conveyed along the deformation of the nip portion of the intermediate transfer medium 6, and at the exit of the nip portion, the sheet 9 tries to move upward in FIG.
Is peeled from the surface of. The sheet 9 whose tip is peeled from the intermediate transfer medium 6 is advanced to the regular transport path by the wedge-shaped guide member 51, and the reattachment of the sheet 9 to the surface of the intermediate transfer medium 6 is prevented.

By the way, if the peeling roller 70 keeps contacting the surface of the intermediate transfer medium 6 with a strong pressing force at all times,
Can cause permanent set of the rubber layer and hence
The transfer performance of the intermediate transfer medium 6 may decrease. In this example, in order to avoid such a problem, a separation mechanism (not shown) is configured to prevent the peeling roller 70 from coming into contact with the intermediate transfer medium 6 when the paper 9 does not advance.

According to the present embodiment, if the thickness of the rubber layer of the intermediate transfer medium 6 is not less than a predetermined value, the intermediate transfer medium 6 is deformed by the conveyance path of the sheet 9 on the intermediate transfer medium 6 and then the intermediate transfer medium 6 is moved by the waist of the sheet 9. The sheet 9 can be peeled from the sheet. that time,
The surface of the intermediate transfer medium 6 is deformed by the metal peeling roller 70 having a small diameter, but when the paper 9 does not advance due to the separating mechanism, the peeling roller 70 is moved to the intermediate transfer medium 6.
Since the surface of the intermediate transfer medium 6 is not contacted with, it is possible to prevent the surface of the intermediate transfer medium 6 from being scratched or deformed. Further, since the metal roller which is easy to manufacture and structure is used as the peeling roller 70, the cost of the roller is low. However, it requires a separating mechanism,
This complicates the device and increases the cost.

FIG. 7 is a view showing the arrangement of a paper peeling member according to the fourth embodiment of the image forming apparatus of the present invention. However, the same parts as those of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description common to the first embodiment relating to image formation is omitted, and only the differences will be described.

The peeling roller 80 of this example is installed on a metal shaft 52 rotatably supported by a bearing (not shown), and is arranged at two positions in the paper width direction. The peeling roller 80 is arranged in the vicinity of the contact portion between the intermediate transfer medium 6 and the pressure roller 7 so as to be able to contact and separate from the intermediate transfer medium 6.

As the peeling roller 80, a roller provided with a rubber layer having a rubber hardness of about 70 is used. Metal shaft 5
A gear pair 82 is provided at the two ends, and the drive motor 8
1, the peeling roller 80 can be driven. The peeling roller 80 is moved by a contact / separation mechanism (not shown) so as to contact the surface of the intermediate transfer medium 6 only when the sheet 9 is conveyed.

Next, the operation of this embodiment will be described.
When the sheet 9 passes through the contact portion between the peeling roller 80 and the intermediate transfer medium 6, the peeling roller 80 is driven by the drive motor 81 so that the surface movement direction thereof is opposite to that of the intermediate transfer medium 6. As a result, the front side of the sheet 9 is shown in FIG.
As shown in FIG. 3, the peeling roller 80 exerts a force to pull the surface of the paper in the direction indicated by the arrow P in the drawing, and a back surface exerts a force to pull the surface of the paper in the direction indicated by the arrow Q in the drawing. Is given.

That is, when tangential forces in different directions are applied to the front and back of the sheet 9, the sheet 9 warps, and the intermediate transfer medium 6
It deforms in the direction of peeling from the surface. Further, there is provided a wedge-shaped guide member 51 for surely guiding the front end of the sheet 9 which has once floated up to the conveyance path, whereby the sheet 9 is appropriately conveyed without being rewound around the intermediate transfer medium 6.

However, if the paper 9 is a thick paper or the like, the paper 9 may not be easily deformed in the direction of peeling from the surface of the intermediate transfer medium 6 even if a shearing force is applied. In some cases, the reliable peeling operation of the sheet 9 cannot be expected unless the size of the sheet is adjusted. Incidentally, the separately required drive source complicates the structure of the apparatus and causes a cost increase.

According to the present embodiment, the peeling roller 80 rotating in the direction opposite to the direction of the intermediate transfer medium 6 gives a shearing force to the sheet 9 to deform the sheet 9 in the direction of peeling from the surface of the intermediate transfer medium 6. The image-transferred paper 9 by
Can be separated from the surface of the intermediate transfer medium 6.
At this time, since the surface of the peeling roller 80 is a rubber layer having a rubber hardness of about 70, the surface of the intermediate transfer medium 6 is not damaged or destroyed.

In the above embodiment, the roller structure for peeling the paper is used. However, the same effect can be obtained even if the belt-shaped peeling means is driven in the direction opposite to the moving direction of the intermediate transfer medium 6. it can.

Further, the present invention is not limited to the above-mentioned embodiment, and can be carried out in various other modes in the concrete constitution, function, action and effect without departing from the gist thereof. . For example, in the embodiment of the present invention, the image forming process using the liquid toner has been described. However, the present invention can be applied to a technique of peeling a sheet from a fixing roller in a fixing unit in an image forming process using a dry toner. Is. Further, even in the image forming process using the liquid toner, the image recording medium 1
It is obvious that the same effect can be obtained by applying the present invention to an image forming apparatus having a structure in which a belt photosensitive member is used for the intermediate transfer medium or a belt transfer member is used for the intermediate transfer medium 6.

[0063]

As described in detail above, according to the present invention, the peeling roller for peeling the paper from the intermediate transfer medium is arranged in the vicinity of the intermediate transfer medium, so that the paper after the image transfer is intermediately transferred. It can be reliably peeled from the medium, troubles such as paper winding and jamming can be prevented, and the reliability of the apparatus can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration according to a first exemplary embodiment of an image forming apparatus of the present invention.

FIG. 2 is a perspective view showing a detailed configuration example of a peeling roller shown in FIG.

FIG. 3 is a diagram illustrating a sheet peeling operation of the peeling roller illustrated in FIG.

FIG. 4 is a diagram showing a configuration of a paper peeling member according to a second embodiment of the image forming apparatus of the invention.

FIG. 5 is a diagram showing a configuration of a paper peeling member according to a third embodiment of the image forming apparatus of the invention.

FIG. 6 is a diagram for explaining a sheet peeling operation of the peeling roller shown in FIG.

FIG. 7 is a diagram showing a configuration of a paper peeling member according to a fourth embodiment of the image forming apparatus of the invention.

FIG. 8 is a diagram illustrating a sheet peeling operation of the peeling roller illustrated in FIG.

[Explanation of symbols]

1 Image recording medium 3-1 to 3-4 laser beam 4-1 to 4-4 developing device 5 Transfer device 6 Intermediate transfer medium 7 Pressure roller 9 Image transfer media (paper) 30 drying nozzle 50, 70, 80 Peeling roller 51 Guide member 60 Cleaning roller (peeling roller)

Claims (5)

[Claims] 1. An image recording medium on which a toner image is formed, an intermediate transfer medium having an elastic surface layer formed opposite to the image recording medium and to which the toner image is transferred, and the intermediate transfer medium. Via a pressure roller that presses the recording medium and conveys the recording medium supplied to the pressing portion to transfer the toner image on the surface of the intermediate transfer medium to the recording medium; and the recording medium on which the toner image is transferred. And a peeling member having an elastic surface layer in which a concave portion is formed, which is pressed against the intermediate transfer medium. 2. An image recording medium having a toner image formed on the surface thereof, an intermediate transfer medium having an elastic surface layer formed facing the image recording medium and having the toner image transferred thereto, and the intermediate transfer medium. A pressure roller that presses the recording medium supplied to the press-contacting portion and transfers the toner image on the surface of the intermediate transfer medium to the recording medium; and the recording medium conveyed by the intermediate transfer medium. An image forming apparatus comprising: a peeling member, which is arranged so as to contact with each other and has an adhesive layer on a surface thereof. 3. An image recording medium on which a toner image is formed, an intermediate transfer medium having an elastic surface layer which is formed so as to face the image recording medium and onto which the toner image is transferred, and the intermediate transfer medium. A pressure roller that is pressed against the recording medium and conveys the recording medium supplied to the pressure contact portion to transfer the toner image on the surface of the intermediate transfer medium to the recording medium; An image forming apparatus comprising: a peeling roller made of a rigid body, which is pressed against the intermediate transfer medium via the recording medium on which an image is transferred. 4. The peeling roller is separated from the intermediate transfer medium before the recording medium is supplied to a contact portion between the intermediate transfer medium and the pressure roller. The image forming apparatus according to item 1. 5. An image recording medium having a toner image formed on the surface thereof, and an elastic surface layer formed opposite to the image recording medium, onto which the toner image is transferred, and having a first rotation direction. An intermediate transfer medium and a recording medium that is pressed against the intermediate transfer medium and supplied to the pressed portion are conveyed to transfer the toner image on the surface of the intermediate transfer medium to the recording medium, and the first rotation direction A pressure roller having a different rotation direction; and a peeling roller that is pressed against the intermediate transfer medium via the recording medium having the toner image transferred thereon and rotates in the first rotation direction. Image forming apparatus.