JP2002132077A - Image processor and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent toner from being electrostatically offset with respect to a toner image processing member 11, such as a fixing roller and a fixing film coming into contact with the toner image carrying surface of a recording material P, on which a toner image (t) is carried. SOLUTION: In this image processor 8, having the toner image processing member 11 which comes into contact with the toner image carrying surface of the recording material P on which the toner image (t) is carried, the member 11 is grounded via a diode 100 and a capacitor 200. The diode is connected to the member 11 so as to generate voltage having the same polarity as the toner, without generating the voltage having a reverse polarity to the toner, and the capacitor is connected to the diode in series.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image processing apparatus and an image forming apparatus.

More specifically, the image forming apparatus has a toner image processing member which comes into contact with a toner image carrying surface of a recording material carrying a toner image,
An image processing apparatus that performs a heat fixing process, a pressure fixing process, a hypothetical deposition process, a surface modification process such as glossing of a toner image, and an electrophotographic system including the image processing device as a toner image fixing device
The present invention relates to an image forming apparatus such as a copying machine or a printer that forms an image by an electrostatic recording method or the like.

[0003]

2. Description of the Related Art Conventionally, as a fixing device (fixing means) of an image forming apparatus, there is a fixing device having a fixing roller and a pressure roller which is driven to rotate in contact with the fixing roller. FIG. 7 shows an example of such a fixing device.

The fixing device 13 heat-presses an unfixed toner image as an unfixed developer image on a transfer material P surface as a recording material by a heat fixing roller 21 and a pressure roller 22. The upper fixing roller 21 is formed by covering the outer peripheral surface of a hollow metal core such as aluminum or iron with a material having good releasability such as PTFE, PFA, or silicone rubber.
A heater 23 such as a halogen lamp is provided in the inner space, and the fixing roller 21 is heated by this heater. The lower pressure roller 22 is formed by coating the outer periphery of a core metal such as iron or stainless steel with an elastic material having releasability such as silicone rubber. The fixing roller 21 and the pressure roller 22 are brought into contact with each other with a predetermined pressing force by an urging means such as a spring (not shown), and are driven to rotate in the direction indicated by the arrow. Reference numeral 24 denotes a temperature-sensitive element such as a thermistor brought into contact with the surface of the fixing roller 21, and detects the surface temperature of the fixing roller 21. The power supply to the heater 23 is controlled by a temperature control circuit in accordance with the temperature detected by the temperature sensing element 24, and the fixing roller 21
Is automatically controlled to a predetermined heat fixing temperature. Reference numeral 25 denotes a separation claw for separating the transfer material from the surface of the fixing roller 21. The separation claw is arranged such that the leading edge portion is brought into contact with the surface of the fixing roller 21 with an appropriate pressing force. Reference numeral 26 denotes a cleaner, such as felt, which is brought into pressure contact with the surface of the fixing roller 21, and wipes and removes toner, paper powder, and the like attached to the surface of the fixing roller 21.

Reference numeral 27 denotes a bottom plate made of a metallic material of the fixing device, and reference numerals 28 and 29 denote transfer material entrance guides and exit guides, which are mounted on and supported by the upwardly bent front and rear walls of the bottom plate 27, respectively. The transfer material P, which receives the transfer of the toner image from the drum surface as an image carrier by a transfer charger as a transfer unit in an image forming unit (not shown), and is conveyed to the fixing device 13, passes through the entrance guide 28,
3, and enters and passes through the nip between the fixing roller 21 and the pressure roller 22 that are rotationally driven while being in pressure contact with each other. In the process of passing through the nip, the unfixed toner image ta on the surface of the transfer material P is
The pressing force between the fixing roller 21 and the pressure roller 22 causes the transfer material P
The surface is fixed by heat and pressure as a permanent fixed image tb. The transfer material P, which has passed through the nip portion of the rollers 21 and 22 and has undergone image fixing, has its leading end separated from the surface of the fixing roller 21 by the separation claw 25, enters a sheet path (not shown) through an exit guide 29, and moves to a discharge tray. Is discharged.

[0006]

However, in the above-described conventional fixing device, the transfer material P as the image bearing material is transferred to both rollers 21.
The image surface passes through the nip portion of the fixing roller 21 and the fixing roller 21.
When moving away from the surface, a part of the toner, which is a developer constituting the image, becomes larger or smaller and adheres to the surface of the fixing roller 21 and remains, so-called offset occurs. If the amount of the offset toner tc is large, it adheres to the separation claw 25 and deteriorates the separability of the transfer material, causing a trouble of winding the transfer material P around the fixing roller peripheral surface, or slipping through the cleaner 26 and causing the temperature-sensitive element 24 to slip. This may result in deterioration of the temperature control performance due to adhesion to the recording medium, or reattachment to the surface of the transfer material to stain the output image surface.

FIGS. 8 (a) and 8 (b) are model views for explaining the offset phenomenon of toner with respect to the surface of the fixing roller 21, and a transfer material sandwiched between a nip portion between the fixing roller 21 and the pressure roller 22. The P toner image portion td is shown.
The amount of offset of the toner constituting the toner image portion td to the surface of the fixing roller 21 is determined by the adhesive force F of the toner to the surface of the fixing roller 21, the adhesive force G of the toner to the surface of the transfer material P, and the fixing roller 21. When the pressure roller 22 and the transfer material P are charged, it is determined by the force E received from the electric field e in the nip portion between the rollers 21 and 22.

The combined force of the above forces F, G, and E is shown in FIG.
Upward (direction toward the surface of the fixing roller 21)
In this case, the offset amount of the toner with respect to the surface of the fixing roller 21 is large, and as shown in FIG.
(Direction toward the surface). Therefore, as described above, the outer peripheral surface of the fixing roller 21 which is in contact with the toner image surface of the transfer material P is coated with a material having good releasability such as PTFE, or a releasing material such as silicone oil is applied to reduce the force F. In order to prevent the generation of the force E, a voltage is applied to at least one of the fixing roller 21 and the pressure roller 22 to lower the force E, or the roller is made conductive to prevent the generation of the force E.

It is also known that the offset can be reduced when the fixing roller 21 is electrically floated with respect to the signal ground of the apparatus, that is, when the fixing roller 21 is not grounded (hereinafter referred to as a float state).

This is because, when the fixing roller 21 is kept electrically floating, the toner slightly offsets to the fixing roller 21 so that the potential of the fixing roller 21 changes to the toner charging polarity side, and the recording material The toner on a certain sheet receives repulsive force from the fixing roller 21.
The offset is reduced by the repulsive force from the fixing roller.

However, when the fixing roller is electrically floated, especially under low humidity, the fixing roller 21 is charged to several KV due to friction with paper and the like, causing electric discharge, thereby generating electric noise due to the electric discharge. As a result, the device may malfunction.

On the other hand, when the fixing roller 21 is grounded, no electrical noise is generated and no malfunction of the apparatus occurs.
There is a problem that the offset increases because no repulsive force is generated from the fixing roller 21 to the toner on the transfer material when the float state is set.

Therefore, as shown in FIG. 9, the core metal 21b is connected to the fixing roller 21 via the diode 10 so that charges of a polarity repelling the toner (in this example, a negative toner is used) are accumulated. Grounding methods are known. 21a
Denotes a release layer, 22b denotes a metal core of the pressure roller 22, and 22a denotes an elastic layer. FIG. 10 shows a voltage-current characteristic curve of the diode 10. As is clear from FIG. 10, the diode 10 has almost zero potential when a current flows in the forward direction (region A), and has a breakdown voltage of about 1 μA when a current flows in the reverse direction (region B). Point (C in the figure, 1 in this example)
KV), and the voltage hardly increases even if a current flows further. Therefore, when the configuration shown in FIG. 9 is employed, when the release layer 21a of the fixing roller 21 has a low resistance, or when the withstand voltage of the film is lowered due to durability, the positive polarity of the recording material applied in the transfer process is reduced. There is a problem that the offset deteriorates due to the charge flowing to the ground.

Further, as shown in FIG.
As described in JP-A-13182 and JP-A-2-1577878, a fixedly supported heating element 61 (ceramic heater) and a heat-resistant film 65 (fixing) conveyed while being pressed against the heating element. A film for fixing the recording material by nipping and transporting the recording material by a heater unit 6 including a film), a film guide 62, a reinforcing sheet metal 63, a thermistor 67, and the like, and a pressing roller 7 for bringing the recording material P into close contact with the heater unit. Also in the heating type fixing device, there is a problem that the toner on the recording material is offset to the fixing film by the same mechanism as described above.

[Purpose] Accordingly, the present invention relates to an image processing apparatus such as a heat roller type or film heating type fixing device described above and an image forming apparatus provided with the image processing device.
This prevents toner from being electrostatically offset with respect to a toner image processing member such as a fixing roller or a fixing film that contacts a toner image bearing surface of a recording material bearing a toner image, and also sets a charging potential of the toner image processing member. It is an object of the present invention to provide a device that does not cause the device to malfunction due to the rise of the device.

[0016]

According to the present invention, there is provided an image processing apparatus and an image forming apparatus having the following features.

(1) In an image processing apparatus having a toner image processing member in contact with a toner image bearing surface of a recording material bearing a toner image, the toner image processing member is grounded via a diode and a capacitor. The diode is connected to the toner image processing member so as to generate a voltage having the same polarity as the toner without generating a voltage having a polarity opposite to that of the toner, and the capacitor is connected in series with the diode. Characteristic image processing device.

(2) The image processing member according to (1), wherein the toner image processing member is a member that heats or pressures the toner image, or heats and presses the toner image. apparatus.

(3) The image processing apparatus according to (1) or (2), wherein the toner image processing member is a rotating body.

(4) The image processing apparatus according to any one of (1) to (3), further including a pressing member for pressing the recording material against the toner image processing member.

(5) The image processing apparatus according to (4), wherein the pressing member is grounded, floating, or grounded via a diode.

(6) The image processing apparatus according to (5), wherein the pressure member is grounded via a diode and a capacitor connected to the toner image processing member.

(7) The toner image processing member is a fixing roller for thermally fixing or pressure fixing the toner image on the recording material.
(1) to (6), wherein the diode and the condenser are connected to a core of the fixing roller.
The image processing apparatus according to claim 1.

(8) The toner image processing member has a flexible film that comes into contact with the toner image bearing surface of the recording material, and a heating element that heats the toner image through the film.
The film has at least an electrically conductive layer and a release layer,
The image processing apparatus according to any one of (1) to (6), wherein the diode and the capacitor are connected to the electric conductive layer.

(9) An image processing apparatus for processing a toner image by holding a pair of rotating members which are in pressure contact with each other and nipping and transporting a recording material carrying a toner image at a pressing portion of the rotating member pair. Of the body pair, the rotating body that contacts the toner image bearing surface of the recording material is grounded via a diode and a capacitor, and the diode is connected to the rotating body by:
An image processing apparatus, which is connected so as to generate a voltage having the same polarity as the toner without generating a voltage having a polarity opposite to that of the toner, and wherein the capacitor is connected in series with the diode.

(10) The image processing apparatus according to (9), wherein the rotating body pair heats or pressures the toner image, or heats and presses the toner image.

(11) The rotating body which comes into contact with the toner image bearing surface of the recording material is a fixing roller for thermally fixing or pressure fixing the toner image to the recording material, and the diode and the condenser are connected to the core of the fixing roller. The image processing apparatus according to (9) or (10), wherein:

(12) The rotating body in contact with the toner image bearing surface of the recording material is a flexible cylindrical film.
A heating element for heating the toner image through the film, wherein the film has at least an electric conductive layer and a release layer, and the diode and the capacitor are connected to the electric conductive layer. The image processing apparatus according to any one of (9) and (10), wherein

(13) The rotator contacting the surface opposite to the rotator contacting the toner image bearing surface of the recording material is grounded, floating, or grounded via a diode. The image processing apparatus according to any one of 9) to (12).

(14) The rotator contacting the surface opposite to the rotator contacting the toner image bearing surface of the recording material is grounded via a diode and a capacitor connected to the toner processing member. (9) to (12)
The image processing apparatus according to claim 1.

(15) In an image forming apparatus having an image forming means for forming an unfixed toner image on a recording material and a fixing means for fixing the unfixed toner image on the recording material, the fixing means may be any of (1) to (14) An image forming apparatus according to any one of the preceding claims.

(16) An image forming means for forming an unfixed toner image on a recording material includes an image carrier, a means for charging the image carrier, and an exposure for forming an electrostatic latent image on the image carrier. The image forming apparatus according to (15), further comprising: a unit; a unit configured to develop the electrostatic latent image as a toner image; and a transfer unit configured to transfer the toner image to a recording material.

[Operation] In other words, since the toner image processing member has the same potential as that of the toner on the surface of the toner image processing member due to the diode, an electrostatic force acts to repel the toner from the toner image processing member. It is possible to prevent occurrence of toner offset from the toner image carrying surface side to the toner image processing surface side. Also, since the toner image processing member is connected to the diode and the capacitor in series and grounded, the transfer charge is prevented from flowing into the ground even if the resistance of the release layer or the recording material of the toner image processing member is reduced. In addition, it is possible to prevent the deterioration of the offset of the toner to the toner image processing member.

[0034]

[First Embodiment] FIG. 1 is a schematic structural diagram of an image forming apparatus according to the present embodiment. The image forming apparatus of this embodiment is a transfer type electrophotographic process, a reversal developing system, and a cleanerless laser printer.

Reference numeral 1 denotes a drum-type electrophotographic photosensitive member (hereinafter, referred to as a photosensitive drum) as an image carrier, which has an organic photosensitive layer formed on an aluminum drum. The aluminum drum is grounded.

The photosensitive drum 1 is driven to rotate at a predetermined peripheral speed in a counterclockwise direction indicated by an arrow by a drive system (not shown).
The rotating photosensitive drum 1 is subjected to charging by a charging roller 2, laser scanning exposure by a laser scanner 3, and development by a developing device 4. The recording material P is applied to the transfer roller 5 of the toner image formed on the photosensitive drum 1.
The transfer of the toner image to the toner image is performed.

The charging roller 2 is in contact with the photosensitive drum 1, and a predetermined charging bias is applied thereto from a bias power supply 31 to uniformly charge the outer peripheral surface of the photosensitive drum 1 to a predetermined polarity and potential. Is done. In this example, the negative electrode is charged to a predetermined potential.

The laser scanner 3 is a semiconductor laser,
It consists of a lens polygon mirror, a motor and the like. The rotation of the polygon and the modulation of the laser according to the image signal are performed by a DC controller (not shown), and the uniformly charged surface of the photosensitive drum 1 is scanned and exposed with the modulated laser light. As a result, an electrostatic latent image corresponding to the scanning exposure pattern is formed on the surface of the photosensitive drum 1.

The developing device 4 is a reversal developing device using a negative-polarity one-component magnetic toner, has a developing sleeve 4a having a built-in developing magnet, and a developing bias is applied to the developing sleeve from a bias power supply (not shown). Then, the electrostatic latent image on the surface of the photosensitive drum 1 is reversely developed.

The transfer roller 5 is pressed against the surface of the photosensitive drum 1 at a predetermined pressure to form a transfer nip portion, and rotates in the forward direction with the rotation of the photosensitive drum 1. The recording material P is fed from a paper feed mechanism (not shown) to the transfer nip at a predetermined control timing, and is nipped and conveyed. During the time when the recording material is nipped and conveyed through the transfer nip portion, a positive bias is applied to the transfer roller 5 from the bias power supply 32 so that the toner image on the photosensitive drum 1 surface is sequentially transferred to the recording material P surface. Is bias-transferred. Recording material P that has left the transfer nip
Are sequentially separated from the surface of the photosensitive drum 1 and introduced into the fixing device 8.

The printer of this embodiment is a cleanerless system which does not have a dedicated cleaner for removing the transfer residual toner remaining on the surface of the photosensitive drum 1 after the recording material is separated.
The untransferred toner is carried to the developing site with the subsequent rotation of the photosensitive drum 1, and is simultaneously collected (cleaned) by the developing device 4 and reused.

The fixing device 8 is of a heat roller type. Reference numerals 11 and 12 denote a fixing roller and a pressure roller which are arranged vertically in parallel and pressed against each other.

The fixing roller 11 has a diameter of 25 mm and a thickness of 1 m.
m PTFE and PFA on the aluminum pipe 11b
A release layer 11a having a thickness of 50 μm is formed. A heater 13 such as a halogen lamp is provided inside.

The pressure roller 12 is made of aluminum core 1
An elastic layer 12b made of silicone rubber and a release layer 12a are sequentially formed on the outer periphery of 2c. Elastic layer 12
b may be conductive or insulating, and the core 12c may be grounded or floated.

The fixing roller 11 and the pressure roller 12 are driven to rotate in the direction of the arrow, and the fixing roller 11 is heated by a heater 13 and the temperature is controlled to a predetermined fixing temperature by a control circuit (not shown). Then, the recording material P carrying the unfixed toner image t is introduced into the fixing nip portion and is nipped and conveyed, so that the heat of the fixing roller 11 and the pressure of the fixing nip portion cause the unfixed toner image t to be transferred to the recording material P. Settled on the surface.

The core metal 11b of the fixing roller 11 includes a high-voltage rectifier diode 100 having a reverse breakdown voltage of 1 KV and a capacity 47.
Ceramic capacitor 200 with pF and breakdown voltage 2KV
Are connected to ground through a series connection. Diode 100
Are connected in such a direction as to maintain the polarity when the fixing roller 11 is charged to a negative polarity having the same polarity as the toner.

As in this embodiment, when the capacitor 200 and the diode 100 are connected in series and the core 11b of the fixing roller 11 is grounded, even if the resistance of the release layer 11a becomes low, the transfer roller is transferred to the recording material P. 5 can be prevented from flowing into the ground via the diode 100. That is, when the recording material P absorbs moisture and the resistance decreases, the transfer bias flows to the ground via the recording material P and the release layer 11a, and the recording material P
It is possible to prevent the toner from being offset from the fixing roller 11 from the toner. In other words, even if the surface resistance of the release layer 11a is not maintained at a high resistance and a high withstand voltage, it is possible to suppress the occurrence of the electrostatic offset due to the transfer of the charge of the recording material P to the ground.

In order to prevent the offset, when the surface resistance of the release layer 11a is set to a high resistance of 10 ¹⁴ Ω · cm or more without connecting the capacitor 200, the transfer roller 5 applies it to the recording material P. The fixing roller 11 is charged with the applied positive charge, the surface of the fixing roller has a positive potential, and an electrostatic offset due to attracting the unfixed toner t is likely to occur. Further, when the resistance of the release layer 11a is increased, especially in a low-humidity environment, when the rear end of the recording material separates from the fixing roller 11, a separation discharge occurs between the recording material P and the fixing roller 11, and the discharge memory is fixed. The occurrence of a so-called peeling offset, which remains on the roller surface and causes a linear offset, also becomes remarkable.

To solve the above problem, if the core metal 11b of the fixing roller is grounded through the series connection of the diode 100 and the capacitor 200 as shown in this embodiment, the release layer 11
Even if the resistance allowable range of a is expanded to the low resistance side, the transfer of the transfer charge to the ground is prevented. Further, if the allowable resistance range of the release layer 11a is expanded to the low resistance side, peeling discharge is less likely to occur when the recording material is separated, and even if a discharge occurs, its potential is immediately attenuated and undetermined. There is no offset of the applied toner. Further, when the toner is slightly offset to the fixing roller 11, the diode 100 operates to hold the negative charge and flow the positive charge to the ground, so that the surface of the fixing roller 11 has a negative polarity having the same polarity as the toner. And the offset of the toner is suppressed by the repulsive force.

According to the study by the present inventors, the smaller the capacitance of the capacitor 200 was, the more effective the reduction of the offset was. That is, the toner of the same charge amount is
It is considered that when the offset is set to 1, the smaller the capacitance, the higher the surface potential and the larger the repulsive electric field to the toner. The capacitance of the capacitor 200 was preferably 100 pF or less.

When the reverse breakdown voltage point of the diode 100 is 100 V or more, the offset is effectively reduced. If the withstand voltage of the capacitor 200 and the diode 100 is high and is used in combination of about 1 to 2 KV, a sufficient effect can be obtained for the reduction of the offset,
In addition, malfunction of the device due to discharge noise does not occur.

As the fixing roller 11, a heat roller having an insulating elastic layer and a release layer each having a thickness of several millimeters formed on a cored bar has a smaller electrostatic capacity. In this case, the potential induced on the surface is increased, and the repulsive electric field for the toner is increased, so that the effect of the present embodiment is more remarkably exhibited.

Although the present embodiment has been described with reference to the case where the negative polarity toner is used as an example, when the positive polarity toner is used, as shown in FIG.
If the connection is reversed, the same effect as described above can be obtained for the positive polarity toner.

[Embodiment 2] This embodiment is a fixing device 8 of a film heating type. FIG. 3 is a perspective model view of a main part of the fixing device 8, and FIG.

Reference numeral 41 denotes a cylindrical fixing film; 42, a ceramic heater (heating body); 43, a film guide made of a heat-resistant resin such as a liquid crystal polymer; and 44, a reinforcing sheet metal. The ceramic heater 42 is fixedly supported on the lower surface side of the film guide 43. Cylindrical fixing film 41
Is loosely fitted to a film guide 43 to which a ceramic heater 42 is attached. The reinforcing sheet metal 44 is inserted inside the film guide 43.

Reference numeral 50 denotes a pressure roller, which comprises a metal core 51 made of aluminum or the like and an elastic layer 52 made of silicone rubber or the like.

The pressure roller 50 is rotatably supported by bearings at both ends of a metal core 51 between device side plates (not shown).
On the upper side of the pressure roller 50, the fixing film 41 is provided.
An assembly (heater unit) of the ceramic heater 42, the film guide 43, and the reinforcing sheet metal 44 is arranged in parallel with the pressure roller 50 with the ceramic heater 42 side facing downward, and the direction of the pressure roller 50 is determined by a biasing means (not shown). And presses down against the elasticity of the pressure roller 50.
As a result, the ceramic heater 42 and the pressure roller 50 are pressed against each other with the fixing film 41 interposed therebetween to form a fixing nip portion having a predetermined width.

The fixing film 41 has a base 41c made of a heat-resistant cylindrical film mainly composed of a polyimide resin.
This is a laminated film in which a primer layer 41b and a release layer 41a are sequentially formed on the outer peripheral surface. More specifically, the base layer 41 c is a 50 μm-thick layer in which a metal oxide filler is dispersed in a polyimide resin,
b is a 4 μm-thick layer mainly composed of carbon black and fluororesin, and the release layer 41 a is a 10 μm-thick layer mainly composed of PTFE and PFA.

The ceramic heater 42 is composed of a resistance heating element 42b made of a silver alloy on an alumina substrate 42a, a glass layer 42c for protecting the resistance heating element, electrical insulation, and ensuring slidability with the film. A thermistor 45 is adhered to the opposite side of the sliding surface.

The reinforcing sheet metal 44 is made of iron or the like, and suppresses deformation of the heater unit when the heater unit including the ceramic heater 42, the film 41, the film guide 43 and the like is pressed against the pressure roller 50. .

The fixing film 41 has a configuration in which a primer layer 41b, which is also a conductive layer, is exposed at one end of the longitudinal direction. The rubber ring 55 is configured to be in pressure contact. The aluminum core 51 is configured to be grounded through a capacitor 200 and a diode 100 via a conductive member including a carbon chip 57 and a stainless spring 56. Reference numerals 46 and 47 are guides for preventing the fixing film 41 from shifting.
Is a connector for guiding the power supply voltage to the resistance heating element 42b of the ceramic heater 42, and 49 is a DC connector for guiding the resistance of the thermistor 45 to a DC controller (not shown) for temperature detection.

Reference numeral 53 denotes a gear fixed to one end of the cored bar 51 of the pressure roller 50. A rotational driving force is transmitted to the gear 53 from a drive source (not shown), and the pressure roller 50 It is driven to rotate in the direction. This pressure roller 50
As a result, the cylindrical fixing film 41 is rotated in the counterclockwise direction as indicated by the arrow while the inner surface of the cylindrical fixing film 41 is in close contact with the downward surface of the ceramic heater 42 and slides in the fixing nip. The pressure roller 50 is driven to rotate, the fixing film 41 is rotated accordingly, and the power is supplied to the ceramic heater 42, so that the ceramic heater 42 generates heat and rises to a predetermined temperature to control the temperature. In this state, the recording material P carrying the unfixed toner image t is introduced between the fixing film 41 and the pressure roller 50 in the fixing nip, and the recording material P
The unfixed toner image carrying surface side is tightly attached to the outer surface of the fixing film 41 and is pinched and conveyed together with the fixing film 41. In this nipping and conveying process, the ceramic heater 4
2 is applied to the recording material P via the fixing film, and the unfixed toner image t is heated and pressed onto the recording material P to be fixed. When the recording material P passes through the fixing nip portion, the recording material P is conveyed with a curvature separated from the outer surface of the rotating fixing film 41.

FIG. 5 is a circuit diagram showing a simplified structure of a film heating type fixing device in which the diode 100 and the capacitor 200 are disposed as described above. Ri is the combined resistance of the resistance of the rubber ring 55 and the contact resistance between the pressure roller core metal 51 and the carbon chip 57.

As described above, also in the film heating type fixing device, the conductive primer layer 41b of the fixing film 41 which contacts the unfixed toner image carrying surface of the recording material P is grounded via the capacitor 200 and the diode 100. The transfer charge applied to the recording material P is transferred to the release layer 41a.
, The occurrence of toner offset caused by flowing into the ground via the contact hole is suppressed, and the primer layer 41b holds charges of the same polarity as the toner, thereby preventing the occurrence of electrostatic offset due to repulsion.

With respect to the grounding configuration of the conductive primer layer 41b, a conductive brush is brought into contact with the exposed portion of the primer layer 41b, and the brush is connected to the capacitor 200 and the diode 100, thereby forming the above-described pressure roller. The primer layer 41b can be grounded without using the cored bar 51, and the effect and action of the present invention can be exerted in this type as well.

FIG. 6 is a circuit diagram showing a case where the primer layer 41b is grounded via the capacitor 200 and the diode 100 independently of the pressure roller core metal 51. Rj is the contact resistance between the primer layer and the conductive brush. Although the pressure roller core metal 51 is grounded, it may be floated or grounded via a diode.

[Other Embodiments] 1) The toner image processing member is not a rotating body but a plate-like body, for example, and may be in contact with the toner image bearing surface of the recording material like a press plate. Good. Alternatively, it may be an end-shaped web-shaped or belt-shaped member driven for traveling.

2) The heating of the toner image processing member may be performed by an electromagnetic induction heating method.

The toner image processing member may be a pressure fixing member.

3) The means for forming a toner image on the recording material P is not limited to the electrophotographic method, but may be a transfer method or a direct type electrostatic recording method, a magnetic recording method, or the like.

[0071]

As described above, by configuring the image processing apparatus and the image forming apparatus, the recording material on which the toner image has been transferred is brought into contact with the toner image in the image processing apparatus for performing the heating and pressing processes. Since the surface of the image processing member has the same polarity as that of the toner, electrostatic force acts to repel the toner from the image processing member, thereby reducing the occurrence of electrostatic offset of the toner. . Furthermore, since the image processing member is connected to a diode and a capacitor in series and grounded, even if the release layer or the recording material of the image processing member has a low resistance, the flow of the transfer charge to the ground is prevented. Therefore, it is possible to prevent deterioration of the offset of the toner to the image processing member.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a main part in a case where a first embodiment of the present invention is applied to an electrophotographic apparatus using a negative polarity toner.

FIG. 2 is a diagram showing a configuration of a main part when the first embodiment of the present invention is applied to an electrophotographic apparatus using a positive polarity toner.

FIG. 3 is a perspective view of a main part configuration of a second embodiment in which the present invention is applied to a film heating type fixing device.

FIG. 4 is a cross-sectional view illustrating a main configuration of a film heating type fixing device.

FIG. 5 is a view showing a grounding configuration of a fixing film according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a modification of the grounding form of the fixing film according to the second embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a configuration of a main part of a conventional fixing device.

FIG. 8 is a view for explaining an offset mechanism of a toner with respect to a fixing roller.

FIG. 9 is a view for explaining a conventional example which is taken as a measure for offsetting toner to a fixing roller.

FIG. 10 is a characteristic curve of voltage and current of a diode used in this example.

FIG. 11 is a view for explaining a conventional example of a film heating type fixing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Organic photosensitive drum 2 Charging member 5 Transfer roller 11a Fixing roller release layer 11b Fixing roller core metal 12, 22, 50 Pressure roller 21 Fixing roller 80 Power supply 85 Triac 100 Diode 200 Capacitor 41a Release layer of fixing film 41b Fixing film Primer layer 42 Ceramic heater 55 Conductive rubber ring 56 Conductive spring ta Unfixed toner tc Offset toner P Recording material

Claims (16)

[Claims] 1. An image processing apparatus having a toner image processing member that contacts a toner image bearing surface of a recording material bearing a toner image, wherein the toner image processing member is grounded via a diode and a capacitor, The diode is connected to the toner image processing member so as to generate a voltage having the same polarity as the toner without generating a voltage having the opposite polarity to the toner.
The image processing apparatus, wherein the capacitor is connected in series with the diode. 2. The image processing apparatus according to claim 1, wherein the toner image processing member is a member that heats or pressures the toner image, or heats and presses the toner image. . 3. The image processing apparatus according to claim 1, wherein the toner image processing member is a rotating body. 4. The image processing apparatus according to claim 1, further comprising a pressing member that presses the recording material against the toner image processing member. 5. The image processing apparatus according to claim 4, wherein the pressing member is grounded, floating, or grounded via a diode. 6. The image processing apparatus according to claim 5, wherein the pressure member is grounded via a diode and a capacitor connected to the toner image processing member. 7. The toner image processing member is a fixing roller for thermally fixing or pressure fixing a toner image on a recording material, and the diode and the capacitor are connected to a core of the fixing roller. Item 7. The image processing apparatus according to any one of Items 1 to 6. 8. A toner image processing member has a flexible film that contacts a toner image bearing surface of a recording material, and a heating element that heats a toner image via the film, wherein the film is at least The image processing apparatus according to any one of claims 1 to 6, further comprising an electric conductive layer and a release layer, wherein the diode and the capacitor are connected to the electric conductive layer. 9. An image processing apparatus, comprising: a pair of rotating members that are in pressure contact with each other, wherein the pressing member of the pair of rotating members sandwiches and conveys a recording material bearing a toner image to process a toner image; Of the pair, the rotating body that comes into contact with the toner image bearing surface of the recording material is grounded via a diode and a capacitor, and the diode does not cause the rotating body to generate a voltage having a polarity opposite to that of the toner. An image processing device connected to generate a voltage having the same polarity as that of the diode, and wherein the capacitor is connected in series with the diode. 10. The image processing apparatus according to claim 9, wherein the rotating body pair heats or pressures the toner image, or heats and presses the toner image. 11. A rotating body that contacts a toner image bearing surface of a recording material is a fixing roller that thermally or pressure-fixes a toner image to the recording material, and the diode and the capacitor are connected to a core of the fixing roller. The image processing apparatus according to claim 9, wherein: 12. A rotating body that contacts a toner image bearing surface of a recording material is a flexible cylindrical film, and has a heating body that heats a toner image via the film. 11. The device according to claim 9, further comprising at least an electric conductive layer and a release layer, wherein the diode and the capacitor are connected to the electric conductive layer.
The image processing apparatus according to claim 1. 13. A rotator that contacts a surface of the recording material opposite to the rotator that contacts the toner image bearing surface is grounded, floating, or grounded via a diode. 13. The image processing device according to any one of 9 to 12. 14. A rotating body contacting a surface opposite to a rotating body contacting a toner image bearing surface of a recording material is grounded via a diode and a capacitor connected to the toner processing member. The image processing apparatus according to any one of claims 9 to 12. 15. An image forming apparatus having an image forming unit for forming an unfixed toner image on a recording material and a fixing unit for fixing the unfixed toner image on the recording material, wherein the fixing unit is any one of claims 1 to 14. An image forming apparatus according to claim 1. 16. An image forming means for forming an unfixed toner image on a recording material comprises: an image carrier; a means for charging the image carrier;
An exposure unit for forming an electrostatic latent image on the image carrier, a unit for developing the electrostatic latent image as a toner image, and a transfer unit for transferring the toner image to a recording material. The image forming apparatus according to claim 15.