JP3071847B2 - Pre-fixing device for copier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pre-fixing processing apparatus in a wet development transfer type copying machine.

[0002]

2. Description of the Related Art An example of a wet development transfer type copying machine will be described with reference to FIG. Around the photoreceptor drum 1 rotating clockwise, a charging charger 2 for uniformly charging the photoreceptor 2 is irradiated along the rotation direction, and the charged photoreceptor drum 1 is irradiated with an original image on a contact glass and statically charged. An exposure unit 3 for forming an electrostatic latent image; an eraser 4 for removing excess charges; a wet developing device 5 for converting the electrostatic latent image into a visible image (toner image) 5; a transfer sheet fed from a paper feeding device 6 A transfer charger 7 for transferring a toner image to the P; a separation roller 8 for separating transfer paper after transfer of the toner image from the surface of the photosensitive drum;
A cleaning device 9 for cleaning the drum surface after the transfer of the toner image, and a static elimination lamp 10 for removing the residual charge of the photoconductor are arranged in this order.

[0003] An electrostatic latent image is formed on the photosensitive drum 1 charged by the charging charger 2 by an exposure unit 3, and the electrostatic latent image is supplied with a developing solution comprising a solvent and a toner of a wet developing device 5. And is visualized as a toner image. The transfer paper fed from the paper feeding device 6 is temporarily stopped by the registration roller 11 and waits, and is again fed in synchronization with the toner image on the photosensitive drum, and is brought into close contact with the peripheral surface of the photosensitive drum 1. And the toner image is transferred. The transfer paper on which the toner image has been transferred and separated from the photosensitive drum 1 is sent to a heating unit 13 after the excess solvent on the toner image carrying surface is removed by a pre-fixing processing unit 12, and the toner image is transferred by this unit. Is heated and fixed, and then sent out of the apparatus by a pair of conveying rollers 14.

Referring to FIG. 15, an example of the prior art of the fixing pre-processing device 12 will be described. The transfer paper P separated from the photosensitive drum 1 by the separation roller 8 is guided by guide plates 8a, 15,
Guided at 16 is sent to the solvent removing means 12. The pre-fixing device 12 includes a blotter roller 12a as a solvent removing member that comes into contact with the toner image bearing surface of the transfer paper P, and a backup roller 12 that presses the transfer paper against the roller.
The excess solvent remaining on the unfixed toner image carrying surface is removed by a non-heating method.
The blotter roller 12a is formed of a material such as a nonwoven fabric having a hygroscopic property. The fixing pretreatment device 12 removes excess solvent in order to achieve satisfactory fixing of the toner image by the heating means described below.

[0005] An example of the heating means will be described with reference to FIG. The fixing roller 13a and the pressure roller 13b are arranged so as to be in pressure contact with each other with the path of the transfer paper P carrying the unfixed toner image therebetween. The fixing roller 13a is in direct contact with the unfixed toner image carrying surface of the transfer sheet, and has a built-in heater 13aa as a heating source. The fixing roller 13a is
It consists of a silicon rubber roller and a Teflon roller.
The pressure roller 13b is pressed against the heating roller 13a at a predetermined pressure by the elastic force of a spring (not shown). Fixing roller 1 surrounded by unit casings 13c and 13d
A thermistor, a thermal fuse, and the like connected to a control device (not shown) are arranged around the device 3a.
3 is controlled. Further, a release agent application felt 13ab and a separation claw 13ac are in contact with the peripheral surface of the fixing roller 13a.

The heating means 13 heats and fixes the toner image from which the excess solvent has been removed by the solvent removing device 12. However, in the case of transfer paper in which the solvent does not easily permeate, such as the second original drawing and the OHP sheet, as shown in the toner image after fixing indicated by reference numeral T5 in FIG. As a result, a phenomenon occurs in which the toner is washed away together with the solvent and the image is significantly disturbed. FIG.
The toner image T4 shown in (d) shows an ideal toner image fixed without being swept.

Here, the form of the toner image from the time when it is separated from the photosensitive drum 1 until it is fixed will be described. The unfixed toner image T1 immediately after the transfer and before passing through the solvent removing device 12 exists in the solvent D on the image bearing surface of the transfer paper P as shown in FIG. In this case, if the cohesive force of the toner particles forming the unfixed toner image T1 is weakened due to the deterioration of the developer over time or the decrease in the amount of charge due to environmental fluctuation, the toner particles and the transfer paper P Due to the small bonding force, there are also some floating toner particles.

When the unfixed toner image in this state passes through the solvent removing device 12, as shown in FIG. 14B, the toner image T2 crushed when pressed by the blotter roller 12a and the backup roller 12b. When this image is sent to the heating means 13, the toner image T5 flows as shown in FIG. 14E, resulting in an image of poor quality. The unfixed toner image T shown in FIG.
Reference numeral 3 denotes a toner image that has not been crushed by the solvent removing device 12.

In order to avoid image flow in the solvent removing section and the subsequent steps, there has been proposed a method in which a means for increasing the cohesive force of deteriorated toner is taken.

In FIG. 15, guide plates 15, which constitute a transfer paper passage between the separation roller 8 and the solvent removing device 12, are provided.
Reference numeral 16 forms a part of the electric field generating means. That is,
The guide plate 16 is grounded and given a function as a counter electrode, and the guide plate 15 is given a function as an electrode plate to which a high-voltage power supply V is connected via a switch S. It is assumed that “negative” charges are given to the toner particles for convenience. When the transfer paper P passes between the electrode plate (15) and the counter electrode (16), the toner particles in the solvent D (see FIG. 14 (a)) In response to the applied electric field, the mutual cohesive force can be increased, and the bonding force with the transfer paper P can be increased.

As shown in FIG. 16, a roller 12aA also serving as a blotter roller as a counter electrode and an electrode roller 12bA also serving as a backup roller constitute an electric field generating means to increase the cohesive force of toner particles and increase the amount of excess toner. It is also conceivable to remove the solvent.

As shown in FIGS. 15 and 16, when the cohesive force of the toner particles is electrically increased at a stage before the solvent removing step, the unfixed toner image after the solvent is removed is denoted by a reference numeral in FIG. It is not crushed as shown by T3,
Is fixed as a toner image T4 which does not flow, as shown in FIG.

[0013]

By the way, the unfixed toner transferred to the transfer paper adheres to the surface of the transfer paper by electric coupling force. Although it adheres with a strong bonding force, the electrical bonding force between the toner particles and the surface of the transfer paper becomes weaker as the distance from the surface of the transfer paper increases. In the prior art shown in FIG. 15, when the amount of solvent or toner adhered to the transfer paper increases due to the environment or other factors, the amount of the remaining solvent increases, or the toner particles in the toner layer and the transfer paper The electric coupling force with the surface becomes weak, there is no margin for the image flow at the time of fixing, and the flow of the image out of the standard occurs.
There is a first problem.

After the transfer, if the solvent cannot be sufficiently removed by the solvent removing device 12 which removes the solvent of the unfixed toner image or if the solvent is unevenly removed, the charge amount of the toner particles due to deterioration of the toner due to running and environmental fluctuations. And the toner particles having a low cohesive force may be washed away by the heating unit 13 to disturb the image. To avoid this, the voltage applied to the transfer charger 7 may be increased. The transfer potential cannot be set too high due to side effects on the image and conveyance. Further, as shown in FIG. 15 and FIG. Although there is a method of increasing the cohesive force of the toner particles by the electric force from the device, there is a second problem that the device becomes bulky.

When a device for injecting electric charge into toner particles forming an unfixed toner image to increase the cohesive force is provided, the hand is easily touched when a transfer paper is jammed.
And the counter electrode 15,
The efficiency is low because the gap between the electrodes 16 cannot be narrowed. Therefore, if the electrodes are enlarged, the device becomes bulky. Also, toner particles adhere to and accumulate on the electrodes, thereby causing transfer paper stains and reducing transfer paper transportability. There is a third problem of damage.

Accordingly, a first object of the present invention is to provide a pre-fixing processing apparatus which has a margin for an image flow at the time of fixing a toner image, and a second object is to provide a pre-fixing apparatus for fixing a toner image without increasing the size of the apparatus. A third object of the present invention is to provide a device capable of performing a process, and to provide a pre-fixing processing device capable of avoiding contamination due to toner adhesion in a transfer paper path and obtaining a toner image without image flow.
What is common is to provide a pre-fixing processing device that can prevent toner image flow and obtain good image quality.

[0017]

SUMMARY OF THE INVENTION A first object of the present invention is to:
Wet development is performed using a predetermined toner, the obtained toner image is transferred to transfer paper, and the solvent on the transfer paper carrying the unfixed toner image is removed by a solvent removing unit. In a wet development transfer type copying machine in which the unfixed toner image is heated by a heating unit in contact with the surface to fix the toner image, a solvent removing unit includes a blotter roller that contacts a toner image bearing surface of a transfer sheet. A backup roller that comes into contact with the back surface of the transfer paper, a high-voltage power supply that applies a bias voltage having a polarity opposite to that of the toner charge to the backup roller, and a blotter roller that can be freely moved toward and away from the backup roller; When the transfer paper has not passed between both rollers, the blotter roller separates from the backup roller and the backup roller has a bias of the same polarity as the toner. It is achieved by a pre-fixing apparatus of claim 1, wherein applying a scan voltage.

According to a second object of the present invention, in the copying machine, the solvent removing means is made of a nonwoven fabric or a felt made of a conductive material such as a metal fiber or a carbon fiber.
Non-heating type solvent removing means comprising a blotter roller disposed on the toner image bearing surface side of the transfer sheet, wherein charge generating means opposed to the blotter roller with a transfer paper path interposed therebetween is disposed; 4. The transfer paper path according to claim 3, wherein the generation means is a charge wire type charge generation means, and a transfer paper path is formed between the plurality of insulating wires provided in the casing opening and the blotter roller. This is achieved by the above-described fixing pretreatment device.

A third object of the present invention is to provide a copying machine in which the solvent removing means is a non-heating type, comprising a blotter roller made of nonwoven fabric, felt or the like and arranged on the side of the transfer paper where the toner image is carried. The blotter roller includes a bias roller that generates an electric field in a direction to bring the toner in the unfixed toner image into close contact with the transfer sheet, and a bias roller between the solvent in the unfixed toner image and the blotter roller. The fixing pretreatment device according to claim 5, wherein at least one or more backup rollers made of an elastic material for increasing a contact area are arranged to face each other.

[0020]

According to the first aspect, a bias voltage having a polarity opposite to that of the toner is applied to a backup roller for sandwiching the transfer sheet between the blotter roller and the transfer roller, thereby removing the solvent and increasing the bonding force between the toner particles and the transfer sheet. .

According to a third aspect of the present invention, while the solvent is removed by a blotter roller made of a conductive material, the binding force between the toner particles and the transfer paper is increased by the charge generating means facing the roller.

5. The transfer sheet according to claim 5, wherein the bias roller in contact with the blotter roller enhances the binding force between the toner particles and the transfer sheet, and the transfer sheet contacts the blotter roller with the bias roller and the backup roller. To increase the contact area.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail, but the same reference numerals will be given to constituent members equivalent to those of the prior art shown in FIG. 15, and detailed description thereof will be omitted. 1 and 2
In the embodiment shown in (1), a solvent removing means 120 is provided in the passage of the transfer paper P carrying the untransferred toner image separated from the photosensitive drum 1 by the separation roller 8. The solvent removing means 120 includes a blotter roller 121 that contacts the toner image bearing surface of the transfer paper, a backup roller 122 made of a conductive material that is in contact with the blotter roller 121, and a positive bias voltage applied to the backup roller 122. And a high-voltage power supply V for applying the voltage. The toner has been given a negative charge. Blotter roller 12
Reference numeral 1 designates a conductive roller as a core metal, around which a thick and liquid-absorbing solvent absorber is formed, and which is grounded via the core metal to serve as a counter electrode. Has a function. A switch S is provided between the high voltage power supply V and the backup roller. The switch S is turned on when the transfer sheet P passes between the rollers.

Then, as shown in an enlarged view in FIG. 2, the transfer paper P carrying the untransferred toner image T1 is
When the sheet is conveyed between the rollers 22, the switch S is turned on to form an electric field between the backup roller 122 and the blotter roller 121. In this case, since a bias voltage having a polarity opposite to that of the toner is applied to the backup roller 122,
As shown in FIG. 14A, the toner particles in the solvent D are attracted to the transfer paper P side to increase the bonding force between the particles and the transfer paper P even when the cohesive force is weak. Therefore, the unfixed toner image T3 remaining on the transfer paper P after the solvent D is suctioned and removed by the blotter roller 121 is shown in FIG.
As shown in (c), an unfixed toner image without image deletion is obtained. When the transfer paper P carrying the untransferred toner image T3 with no image flow is sent to the heating means 13 and heated by the fixing roller 13a and the pressure roller 13b, the unfixed toner image T3 becomes the image shown in FIG. The toner image is fixed as an image having no image flow like the toner image T4 shown in FIG.

In the embodiment shown in FIGS. 3 and 4, the core of the blotter roller 121 is connected to a high-voltage power supply V1 for applying a negative bias voltage having the same polarity as that of the toner. A positive bias voltage having a polarity opposite to that of the toner is applied to the backup roller 122 by the high voltage power supply V.

The application of the bias voltage by the power supplies V and V1 is performed under the control of the switches S and S1, and is turned on when the transfer paper P is transported between the rollers 121 and 122. According to this embodiment, the potential difference between the blotter roller 121 and the backup roller 122 becomes large, and the toner particles during the removal of the solvent D are more effectively attracted to the transfer paper side, so that the image flow can be avoided. In FIG. 4, an unfixed toner image T3 represents an image in which no image flow has occurred as shown in FIG.

In FIG. 1, the backup roller 122
Is provided with a tip portion of a cleaning pad 123 as a cleaning means made of a rubber blade, a nonwoven fabric, a felt, or the like, in contact with the peripheral surface thereof. The cleaning pad 123 contacts the unfixed toner image carrying surface of the transfer paper P to remove toner particles transferred from the peripheral surface of the blotter roller 121 to which the toner particles have adhered to the peripheral surface of the backup roller 122 to remove the toner particles. Is prevented, and the function of the roller 122 as an electrode is maintained. In the embodiment shown in FIG. 3, a cleaning pad 123 may be provided.

In FIG. 1 and FIG.
Reference numeral 1 is supported by a support mechanism (not shown) so as to be freely movable toward and away from the backup roller 122. When the transfer paper P does not exist between both rollers, the blotter roller 121
Is held at a position separated from the backup roller 122, and the switches S and S1 are turned off so that no electric field is generated. When the transfer paper P is conveyed between the two rollers, the blotter roller 121 comes into contact with the backup roller 122 to absorb and remove the excess solvent D, and the switches S and S1 are turned on to turn on the backup roller 122 (and the blotter). A high voltage is applied to the roller 121) to generate an electric field between the blotter roller 121 (and the backup roller 122) to attract toner particles of the unfixed toner image on the transfer paper toward the transfer paper.

In the embodiment shown in FIGS. 1 and 2, when the blotter roller 121 is separated from the backup roller 122, the cleaning pad 12 is applied to the backup roller 122 while applying a voltage having the same polarity as that of the toner.
When the cleaning of the peripheral surface of the roller 3 is performed, the cleaning can be efficiently performed for removing the toner.

Referring to FIGS. 5 and 6, another embodiment of the present invention will be described. In another transfer paper path carrying the unfixed toner image T1, a blotter roller 131 serving as a solvent removing means disposed on the side of the transfer paper P which is in contact with the toner image carrying surface.
And a charger 132 as charge generation means disposed opposite to the blotter roller 131 with the transfer paper path interposed therebetween. The blotter roller 131 has a peripheral surface made of a conductive and liquid-absorbing material such as metal fiber or carbon fiber, and is grounded.

Charge wire 132 of charger 132
A voltage having a polarity (positive) opposite to that of the toner is applied to a through a high-voltage power supply (not shown). When the transfer paper P separated from the photosensitive drum 1 passes between the charger 132 and the blotter roller 131, a positive charge having a polarity opposite to that of the toner is applied to the back surface of the transfer paper P, and at the same time, the blotter roller 131 Removes excess solvent D by suction.

In another embodiment of the present invention shown in FIGS. 6 and 7, an insulating wire 133 such as a nylon wire is stretched over the opening of the charger 132 on the blotter roller 131 side. The wire 133 is wrapped around the transfer paper P so as to be divergent in the traveling direction, thereby preventing the transfer paper P from wrinkling.

The wire 133 and the blotter roller 131 are
As shown in FIG. 6, the wires are arranged so as to bend and be in contact with each other to form a transfer paper path. When the conveyed transfer paper P is conveyed through the path formed by the blotter roller 131 and the wire 133, the unfixed toner image T1 before entering between the two becomes, as shown in FIG. In some cases, the toner particles contain a large amount of toner particles, and some of the toner particles themselves have a small charge amount, so that the cohesive force may be weak. When the unfixed toner image T1 passes between the blotter roller 131 and the wire 133, the toner particles are electrically attracted to the transfer paper side by the positive charge by the charge wire 132a, and the cohesive force of the toner image is reduced. Can be strengthened. Further, the excess solvent D is removed by the blotter roller 131.
Accordingly, as shown in FIG. 14C, the unfixed toner image T3 that has passed through the blotter roller 131 has a group of toner particles. Even if the toner particles are sent to the heating unit 13 and fixed, there is no image flow. The image is fixed as an image having a sharp outline as shown in FIG.

In the embodiment shown in FIG. 6, when the transfer paper is not passed, the blotter roller 131 is connected to the wire 133.
, The tension may be reduced due to the elongation of the wire.

FIG. 8 shows a seventh embodiment of the present invention which employs a structure for preventing the tension of the wire 133 from lowering and preventing the transfer paper from being stained by the toner attached to the wire. A hollow backup roller 134 made of an insulator such as a polyester film or glass is in contact with the blotter roller 131 to form a nip portion of a transfer paper path. On the outer peripheral surface of the backup roller 134, a blotter roller 131 is provided.
A cleaning pad 135 as cleaning means is in contact with a position excluding the contact portion. Further, inside the backup roller 134, the blotter roller 13
The charger 136 is provided at a position facing the cleaning pad 135, and the charger 137 is provided at a position facing the cleaning pad 135. The charger 136 generates a charge having a polarity opposite to that of the toner and draws the toner of the unfixed toner image T1 toward the transfer paper P.

The charger 137 includes the blotter roller 13
The toner transferred from 1 to the surface of the backup roller 134 is easily separated from the surface of the roller, and the cleaning effect of the cleaning pad 135 is improved. By providing the backup roller 134 rotatably,
The transfer resistance of the transfer paper P is reduced, and the back contamination of the transfer paper can be avoided. As for the image flow, the same effect as that of the embodiment shown in FIG. 6 can be obtained.

Referring to FIG. 9, another embodiment of the present invention will be described. In the transfer paper path between the separation roller 8 and the heating means 13, a blotter roller 141 as a solvent removing means is arranged on the toner image bearing surface side of the transfer paper P. The blotter roller 141 is made of a liquid-absorbing material such as a nonwoven fabric or a felt, and is a non-heating type solvent removing unit.

On the blotter roller 141, a bias roller 142 and a backup roller 143 which are in contact with the back side of the transfer paper are arranged in contact with each other. At least one of these rollers 142 and 143 is provided. The bias roller 142 is a conductive roller,
The switch is selectively connected to the positive electrode of the high-voltage power supply V via the switch S, and generates an electric field between the switch and the blotter roller 141 as a counter electrode. This electric field acts in a direction in which the toner of the unfixed toner image is attracted to the transfer paper side and brought into close contact therewith.

Blotter roller 141 and bias roller 1
If the core of the blotter roller as the counter electrode is made large in order to efficiently generate an electric field between the roller and the roller, the surface layer serving as the solvent absorbing layer of the roller must be thinned in terms of space. When the bias roller 142 is a conductive roller made of a metal roller or a hard roller having a thin rubber layer, the generation of an electric field is efficient,
A large area nip cannot be expected between the bias roller and the blotter roller, and the solvent removal amount cannot be said to be sufficient.

Therefore, the backup roller 143 is made of an elastic material such as rubber or sponge.
The nip between the transfer paper P and the blotter roller 141 is increased. In this embodiment, the transfer paper P carrying the unfixed toner image T1 is brought into contact with the blotter roller 141 by the bias roller 142 and the backup roller 143. In other words, the nip with the blotter roller is set to be large. Therefore, the solvent can be sufficiently removed. In addition, the blotter roller 141 as a counter electrode
The toner image T2 (see FIG. 10) in the electric field formed between the electrode and the bias roller 142 as an electrode is shown in FIG.
As shown in (c), the toner particles are attracted toward the transfer paper P in the direction of the electric field, and the bonding force between the toner particles and the transfer paper is strengthened. No image is generated, and an image without image deletion as shown in FIG. 14D is obtained.

Referring to FIG. 10, another embodiment of the present invention will be described. The bias roller 142 has a changeover switch S2
And a second high-voltage power supply V that applies a charge of the same polarity as the toner.
3 are selectively connected. The blotter roller 141 is supported so as to be separated from the rollers 142 and 143 when the transfer paper P is not passed. A cleaning pad 44 as cleaning means made of felt, nonwoven fabric, or the like is brought into contact with the peripheral surface of the bias roller 142.

Then, the transfer paper P is transferred to the blotter roller 141.
When the sheet is not conveyed between the bias roller 142 and the backup roller 143, the blotter roller 141 is held at the retracted position separated from the rollers 142 and 143. At this time, the changeover switch S2 is switched to the position shown by the broken line in FIG. 10 to apply the same polarity charge to the bias roller 142 as the toner. The rotating bias roller 142 cleans toner adhered to its peripheral surface by the polarity of the applied charge and the cleaning pad 144.

When the transfer paper P is fed between the blotter roller 141, the bias roller 142, and the backup roller 143, the blotter roller 141
2, 143 in the illustrated position. At this time, a positive charge having a polarity opposite to that of the toner of the first high-voltage power supply V is applied to the bias roller 142 via the changeover switch S2 switched to the solid line position, and an electric field is generated between the bias roller 142 and the blotter roller 141. Form. This electric field strengthens the bonding between the particles of the unfixed toner image T1 (see FIG. 14A) as shown in FIG. 14C and draws it toward the transfer paper. The solvent D on the transfer paper surface, which is conveyed while contacting the blotter roller 141 while being drawn to the transfer paper side by the electric field between the two rollers, is efficiently sucked and removed by the blotter roller, and the unfixed toner image T3 (FIG. 14) (See (c)) to the heating means 13.

Heating means 1 having an increased bonding force with transfer paper
As shown in FIG. 14D, the unfixed toner image T3 sent to the printer 3 is fixed as a toner image T4 having a sharp outline, as shown in FIG. In the case of this embodiment, when the three-roller system is employed, the pre-fixing process can be performed in a shorter transfer paper transport path than in the example shown in FIG. 16, and the apparatus can be reduced in size.

Referring to FIGS. 11 and 12, another embodiment of the present invention will be described. In this embodiment, the process of drawing the toner particles to the transfer paper side almost simultaneously with the fixing of the toner image is executed. In the present invention, this timing is also included in the pre-fixing process.

Between the separation roller 8 and the heating means 13,
A blotter roller 151 and a backup roller 152 as solvent removing means are provided. These rollers may be provided with the electric field generating means and the charge applying means as described above.

A charger 153 is provided near the fixing roller 13a of the heating means 13. Charger 15
Reference numeral 3 is connected to the negative electrode of the first high-voltage power supply V4 via the switch S4, and acts in a direction in which the unfixed toner is brought into close contact with the transfer paper.

On the other hand, a charger 154 is provided near the pressure roller 13b. This charger 154
Is connected to the second high-voltage power supply V5 via the switch S5. The charger 154 applies a charge having a polarity opposite to that of the toner to the pressure roller 13b to aggregate the toners and to attract the toner to the transfer paper so that the toner adheres to the transfer paper. A distal end portion of a cleaning member 155 as a cleaning unit made of a rubber blade, a nonwoven fabric, or the like is provided in contact with the peripheral surface of the pressure roller 13b.

In FIG. 12, when the transfer paper P carrying the unfixed toner image T1 passes through the blotter roller 151 and the backup roller 152, a certain amount of the solvent D is removed, and the heating means is converted into an unfixed toner image T3. Go to 13. In this case, the unfixed toner image T3 ideally corresponds to FIG.
As shown in FIG. 4 (c), it is desirable to control the amount of the solvent to the minimum, but it is difficult to always strictly control this. Also, at this stage, the electric coupling force between the toner particles and the transfer paper is weak, and an image flow may occur during fixing.

However, in this embodiment, when the transfer paper P carrying the unfixed toner image T3 from which the solvent has been removed enters the heating means 13, the toner particles are applied to the fixing roller 13a. However, the toner is electrically pushed to the transfer paper side by the negative charge of the opposite polarity to the toner, and is attracted to the charge of the same polarity as the toner applied to the pressure roller 13b, so that the toner is transferred to the transfer paper. The fixing roller 13a is heated by the fixing roller 13a receiving the heat of the heater 13aa while being closely contacted. Thereby, the toner image T4 becomes
As shown in FIG. 14D, even if the amount of the solvent attached is large, the solvent is fixed to the transfer paper P with a strong bonding force without flowing.

When the transfer paper P does not pass, the fixing roller 1
3a and the charge of the pressure roller 13b are canceled, and the toner attached to the peripheral surface of the pressure roller is removed by the cleaning member 15a.
5 to prevent the transfer paper from being stained on the back side and to keep the surface as an electrode clean.

[0052]

According to the first aspect of the present invention, the electric bonding force between the unfixed toner image transferred onto the transfer paper and the surface of the transfer paper can be strengthened, and the amount of solvent adhesion and the amount of toner adhesion increase. Under such conditions, the image flow after passing through the heating means can be eliminated. Also, the offset from the blotter roller to the backup roller can be minimized by contacting the blotter roller and the backup roller only when paper is passed, and the backup is performed by applying a bias of the same polarity as the toner to the backup roller. The cleaning of the toner adhered to the roller can be effectively performed, and the bias property can be favorably maintained.

According to the second aspect of the present invention, since a bias is applied to the backup roller with a polarity opposite to that of the toner, an offset from the blotter roller to the backup roller is likely to occur. In addition, the surface of the backup roller can always be kept normal, so that the back surface of the transfer paper can be prevented, and the bias performance can be maintained satisfactorily.

According to the third aspect of the present invention, since the solvent of the unfixed toner image is removed by the non-heating type blotter roller and the electric charge is applied, the cohesive force of the toner particles can be strengthened. Image disturbance can be prevented. Further, a wide nip portion can be formed by the wire and the blotter roller, so that a sufficient solvent can be removed, and the cohesive force of the toner particles can be increased by the charge generating means, thereby preventing image flow.

According to the fourth aspect of the present invention, by providing the backup roller facing the blotter roller, good transferability of the transfer paper can be obtained, and the solvent and the solvent are provided by the charger and the blotter roller provided inside. Removal and improvement of toner cohesion can be realized. In addition, the cleaning means provided on the outer peripheral surface of the backup roller and the charger provided inside the roller opposite thereto can maintain the performance for easily cleaning the surface of the backup roller.

According to the fifth aspect of the present invention, since the bias roller and the backup roller are brought into contact with the blotter roller, the contact area between the transfer paper and the blotter roller can be increased, sufficient solvent can be removed, and toner cohesion can be improved. Can be improved to prevent image deletion. Further, the device can be compactly assembled.

According to the present invention, the surface of the bias roller can be easily and satisfactorily cleaned, so that the performance of the bias roller can be maintained satisfactorily.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing an embodiment of the present invention according to claims 1 and 2.

FIG. 2 is an enlarged view of a main part of the embodiment according to claim 1;

FIG. 3 is a front view of the embodiment according to claim 1;

FIG. 4 is an enlarged view of a main part of FIG. 3;

FIG. 5 is a front sectional view of the embodiment according to claim 3;

FIG. 6 is an enlarged view of a main part of the embodiment according to claim 3;

FIG. 7 is a plan view showing the relative positions of the charge generating means and the transfer sheet according to the third embodiment.

FIG. 8 is an enlarged front sectional view of the embodiment according to claim 4;

FIG. 9 is a front sectional view of the embodiment according to claim 5;

FIG. 10 is an enlarged view of a main part of the embodiment according to claims 5 and 6;

FIG. 11 is a front sectional view of another embodiment of the present invention.

FIG. 12 illustrates the operation of another embodiment of the present invention.
It is a principal part enlarged front view.

FIG. 13 is a schematic front view showing an example of a wet development transfer type copying machine to which the present invention is applied.

FIG. 14 shows an unfixed toner image before and after performing a pre-fixing process;
FIG. 3 is an enlarged cross-sectional view illustrating a form of a toner image after a fixing process.

FIG. 15 is a front sectional view showing an example of a conventional fixing pretreatment device and a heating unit.

FIG. 16 is a front sectional view showing another example of the conventional fixing pretreatment device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Photoreceptor drum 7 ... Transfer charger 8 ... Separation roller 8a ... Guide plate 13 ... Heating means 13a ... Fixing roller 13b ... Pressure roller 120 ... Before fixing Processing device 121 Blotter roller 122 Backup roller 123 Cleaning pad V High-voltage power supply V1 Second high-voltage power supply 131 Blotter roller 132 Charger 133 Insulation Sex wire 134 Backup roller 135 Cleaning pad 136 Charger 137 Charger 141 Blotter roller 142 Bias roller 143 Backup roller 144 Cleaning pad V3 ..High-voltage power supply 151 ・ ・ ・ Blotter roller 152 ・ ・ ・ Backup roller La 153 ... Charger 154 ... charger 155 ... cleaning member V4 ... first high voltage power supply V5 ... second high-voltage power source

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshito Ikeda 1-3-6 Nakamagome, Ota-ku, Tokyo, Ricoh Company Limited (72) Inventor Kazuo Ogawa 1-3-3 Nakamagome, Ota-ku, Tokyo No. 6, Ricoh Co., Ltd. (56) References JP-A-2-71286 (JP, A) JP-A-2-212149 (JP, A) JP-A-49-91459 (JP, A) JP-A-63 JP-A-289572 (JP, A) JP-A-55-96970 (JP, A) JP-A-59-90876 (JP, A) JP-A-2-95357 (JP, U) JP-A-57-201564 (JP, U) ) Actually open 60-39065 (JP, U) Actually open 44-4866 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 21/00 G03G 21/10-21 / 12 G03G 13/20 G03G 15/20-15/20 302 G03G 15/10-15/11

Claims (6)

(57) [Claims] And performing wet development using a predetermined toner.
The obtained toner image is transferred to a transfer sheet, and the solvent on the transfer sheet carrying the unfixed toner image is removed by a solvent removing unit. Then, the unfixed toner image is transferred to the transfer sheet by a heating unit in contact with the toner image bearing surface of the transfer sheet. In a wet development transfer type copying machine in which a toner image is heated to fix the toner image, the solvent removing unit includes a blotter roller that contacts a toner image bearing surface of a transfer sheet and a backup roller that contacts a back surface of the transfer sheet. The backup roller is provided with a high-voltage power supply for applying a bias voltage having a polarity opposite to the charge of the toner, and the blotter roller is provided so as to be able to freely contact and separate from the backup roller. If it has not passed, the blotter roller separates from the backup roller and a bias voltage of the same polarity as the toner is applied to the backup roller. Fixing pretreatment apparatus characterized by. 2. The fixing pretreatment apparatus according to claim 1, wherein said backup roller is provided with a cleaning means comprising a rubber blade, a nonwoven fabric, a felt, or the like. 3. Performing wet development using a predetermined toner,
The obtained toner image is transferred to a transfer sheet, and the solvent on the transfer sheet carrying the unfixed toner image is removed by a solvent removing unit. Then, the unfixed toner image is transferred to the transfer sheet by a heating unit in contact with the toner image bearing surface of the transfer sheet. In a wet development transfer type copying machine in which a toner image is heated to fix the toner image, the solvent removing means is made of a nonwoven fabric made of a conductive material such as metal fiber or carbon fiber, felt, or the like. Non-heating type solvent removing means comprising a blotter roller disposed on the toner image bearing surface side of the transfer paper, wherein charge generating means opposed to the blotter roller with a transfer paper passage interposed therebetween is provided; The generation means is a charge wire type charge generation means, and a transfer paper path is formed between the plurality of insulating wires provided in the casing opening and the blotter roller. Pre-fixing processing apparatus that. 4. A hollow backup roller is provided opposite to the blotter roller, and a charge generation means having a polarity opposite to that of the toner is provided at a position of the backup roller facing the blotter roller. 4. A fixing device according to claim 3, wherein a backup roller cleaning means is provided in a part other than the blotter roller contact portion, and a charge generation means having the same polarity as the toner is provided inside the backup roller opposed to the cleaning means. Processing equipment. 5. Performing wet development using a predetermined toner,
The obtained toner image is transferred to a transfer sheet, and the solvent on the transfer sheet carrying the unfixed toner image is removed by a solvent removing unit. Then, the unfixed toner image is transferred to the transfer sheet by a heating unit in contact with the toner image bearing surface of the transfer sheet. in heating the toner image copier wet development transfer method for performing fixing of the toner image, blotter b of the solvent removal means, arranged nonwoven, a toner image carrying surface side of the transfer sheet consist such as felt
And a bias roller for generating an electric field in a direction to bring the toner of the unfixed toner image into close contact with the transfer paper; a solvent for the unfixed toner image and the blotter. A fixing pretreatment device, wherein at least one or more backup rollers made of an elastic material for increasing a contact area between the roller and the roller are arranged to face each other. 6. A cleaning device is provided on the bias roller, and the blotter roller is provided so as to be able to freely contact and separate from the bias roller. When the transfer paper does not pass between the two rollers, the blotter roller is separated from the bias roller. 6. The pre-fixing device according to claim 5, wherein a bias voltage having the same polarity as that of the toner is applied to the bias roller.