JPH081536B2 - Image forming device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer, and more particularly to an image forming apparatus having a fixing rotating member to which a release agent is applied.

[0002]

2. Description of the Related Art Conventionally, various multicolor (full color) image forming apparatuses have been proposed. For example, FIG. 5 shows a typical multicolor electrophotographic copying machine equipped with a developing device called a so-called rotary developing device. To be done.

Briefly described with reference to FIG. 5, a multicolor electrophotographic copying machine is provided with an image carrier, which is rotatably supported and rotates in the direction of an arrow, that is, a photosensitive drum 3, and an outer peripheral portion thereof. Image forming means. The image forming means may be any means, but here, the photosensitive drum 3 is used.
Exposure that comprises a primary charger 4 for uniformly charging the surface of the photosensitive drum 3 and a color-separated light image or a light image corresponding thereto to form an electrostatic latent image on the photosensitive drum 3, for example, a laser beam exposure device. Means 8 and the rotary developing device 1 for converting the electrostatic latent image on the photosensitive drum 3 into a visible image are provided.

The rotary developing device 1 includes four developing units 1Y, 1M, 1C and 1BK for accommodating four color developers of yellow, magenta, cyan and black, respectively, and these four developing units. The developing device 1Y, 1M, 1C, 1BK is carried, and is composed of a substantially cylindrical housing rotatably supported. The rotary developing device 1 conveys a desired developing device to a position facing the outer peripheral surface of the photosensitive drum 3 by rotation of a housing, develops an electrostatic latent image on the photosensitive drum, and performs full color development for four colors. It is configured to do.

A visible image, that is, a toner image on the photosensitive drum 3 is, in this case, a transfer drum 9 which is rotatably supported.
Is transferred to a transfer material P carried and carried by a transfer device composed of As will be understood with reference to FIG. 6, this transfer drum includes cylinders 9a and 9b arranged at both ends,
The cylinder 9a and 9b are connected to each other, and the transfer material carrying member 93 is stretched in the outer peripheral surface opening area of the cylinders 9a and 9b. This transfer material carrying member 9
For 3, a film-shaped dielectric sheet such as a polyethylene terephthalate or polyvinylidene fluoride resin film is usually used. Further, the connecting portion 9c has a transfer material gripper 7 that holds the transfer material P fed from the paper feeding device. Further, inside the transfer drum 9, a transfer discharger 10 and an inside charge-eliminating discharger 13 forming a charge-eliminating means are arranged, and outside, an outside charge-eliminating discharger 11 is arranged.

Next, a process of forming a full-color image by the multicolor electrophotographic copying apparatus having the above-mentioned structure will be briefly described.

First, the photosensitive drum 3 is uniformly charged by the primary charging device 4, and the exposure means 8 irradiates the optical image E corresponding to the image information to form an electrostatic latent image on the photosensitive drum 3.
This electrostatic latent image is transferred to the photosensitive drum 3 by the rotary developing device 1.
The toner is visualized as a toner image by using a resin-based toner having an average particle diameter of about 12 μm.

On the other hand, the transfer material P is sent to the transfer drum 9 by the registration rollers 6 in synchronism with the image, and is conveyed in the direction of the arrow in the figure by the transfer drum 9 with its tip end gripped by the gripper 7. To be done.

Next, in the area contacting the photosensitive drum 3, the transfer material carrying member of the transfer drum 9, that is, the rear surface of the dielectric sheet 93, is transferred to the transfer discharger 10 serving as a transfer means.
The toner image on the photosensitive drum 3 is transferred onto the transfer material P by being subjected to corona discharge having a polarity opposite to that of the toner.

The transfer material P is peeled from the transfer drum 9 by the action of the separating claw 15 while being subjected to the charge removal by the charge removing dischargers 11 and 13 after the transfer process is performed a required number of times, and is fixed by the conveyor belt 16. It is transported to the container 17. After being fixed by heat by the fixing device 17, the paper is discharged to the outside of the machine.

On the other hand, after the residual toner on the surface of the photosensitive drum 3 is cleaned by the cleaning device 12, the photosensitive drum 3 is subjected to the image forming process again.

The surface of the dielectric sheet of the transfer drum 9 is also
Similarly, a cleaning device 18 such as a fur brush
After being cleaned by the action of the cleaning assisting means 19, it is subjected to the image forming process again.

As the fixing device 17, there is used a roller fixing method, particularly a heat roller fixing method, in which a transfer material supporting a toner image is sandwiched and conveyed by a pair of rollers to carry out fixing while applying pressure. In this heat roller fixing method, a release agent such as silicone oil is applied in order to prevent toner offset. Particularly in a full-color image forming apparatus in which toner is laminated in multiple layers, the toner is likely to be offset, so that a large amount of toner is applied. Applying silicone oil.

A resin film such as a transparency film is also used as the transfer material.

[0015]

However, in the conventional image forming apparatus as described above, when the toner image on the transfer material is fixed by the fixing roller coated with silicone oil, the transfer material after fixing is formed by the oil. In the case of double-sided copying in which an image is formed again on the back surface (second surface) by using a transfer material on which the toner is once fixed on the front surface (first surface), wetting or stickiness occurs. There was a problem that the adhered oil was transferred to the photosensitive drum and adhered there, thereby contaminating the next image. Further, as shown in FIG. 5, the transfer material once fixed is re-fed to the transfer drum 9 by the registration roller 6 in synchronization with the image, and the tip of the transfer material is gripped by the gripper 7 so that the first surface of the transfer material is removed. Transfer drum 9
The transfer material carrying member, that is, the dielectric sheet 93, is conveyed in the direction of the arrow in the figure.

A transfer process similar to that for the first surface is performed on the second surface of the transfer material, and then the transfer material is separated from the transfer drum 9 and fixed by the fixing device 17 to obtain a double-sided copy image.

However, the oil, which is the release agent adhered to the first surface of the transfer material, the dielectric sheet is used after the transfer step of the second surface is completed and the transfer material is peeled off from the transfer drum 9. 93 is transferred and adhered to the surface of the photosensitive drum 3 and the transfer drum 9.
There is a problem that the surface of the dielectric sheet 93 is again transferred and adhered to the surface of the photosensitive drum 3 during the contact rotation with and the surface of the photosensitive member is contaminated. In the next copying step, the oil transferred to the photosensitive member is changed. The waste toner and the developing toner adhere to the toner and are transferred onto the transfer material, resulting in image smearing and fogging.

In the conventional image forming apparatus, the cleaning device 12 and the cleaning device 18, which are elastic blades, for example, do not have the ability to remove the oil adhering to the photosensitive drum 3 and the dielectric sheet 93. The drum and dielectric sheet had to be replaced, which had the drawback of leading to extremely high costs and poor serviceability.

Attempts have also been made to reduce the amount of silicone oil, which is a release agent, applied to the fixing roller to reduce the amount of oil that adheres to the first surface of the transfer material. Although transfer and adhesion to the photosensitive drum is avoided, oil is accumulated little by little on the dielectric sheet 93 of the transfer drum 9 during the double-sided copying process, and eventually transferred and adheres to the photosensitive drum. The problem was that

[0020]

SUMMARY OF THE INVENTION The present invention aims to solve the above-mentioned problems in the conventional image forming apparatus.

According to the present invention, an image carrier on which a toner image is formed, a transfer material carrying member which holds and conveys a transfer material,
A transfer unit that transfers the toner image on the image carrier to the transfer material, and a fixing rotator coated with a release agent apply at least pressure and heat to the toner image transferred to the transfer material to fix the toner image. In the image forming apparatus provided with a fixing unit for carrying out, the transfer material carrying member comprises a base and a release agent absorbing layer which is provided on the surface of the base and absorbs the release agent. An image forming apparatus is provided.

Further, the present invention is characterized in that a release agent holding layer is provided as a layer below the release agent material absorbing layer, and further the release agent holding layer is included in the release agent absorbing layer. It is characterized in that it is composed of spherical particles having a smaller particle size than the spherical particles.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image forming apparatus according to the present invention will be described in detail below with reference to the drawings.

The transfer sheet, which is the transfer material carrying member of the image forming apparatus shown in each of the following embodiments, can be used in the multicolor electrophotographic copying apparatus described above with reference to FIGS. 5 and 6. .

(Embodiment 1) FIG. 1 is a sectional view of a transfer sheet 93 which is a transfer material carrying member according to the present invention. In FIG. 1, reference numeral 94 is a dielectric sheet that is a substrate, and includes polyethylene terephthalate (PET), polyamide, polyimide, polyvinylidene fluoride (Pvdf), urethane resin, or carbon in these resins.
A sheet having a volume resistivity controlled by dispersing fine metal powder or the like and having a thickness of about 75 μm to 300 μm can be advantageously used including mechanical strength.

Reference numeral 95 denotes a release agent absorbing layer provided on the substrate 94, which contains spherical particles and has a thickness of 3 μm to 50 μm.
Those having a thickness of μm are preferable from the viewpoints of release agent absorbability and holding ability.

In this embodiment, mixed silica spherical fine particles having an average particle diameter of 2 μm and 1 μm were used as the spherical particles.
Styrene-acrylic resin was used as the binder resin, and the amount used was 10 to 40 wt% with respect to the total amount of the particles.

At this time, the mixing ratio of the particles and the binder is
If the amount of the binder used is too small, the particles cannot be sufficiently bound on the substrate 94, and if the amount is too large, the binder becomes rich, and sufficient voids cannot be maintained between the spherical particles. Absorption capacity is significantly reduced, which is not preferable.

The above-prepared mixture was mixed with a conventional disperser, T
Stir with a K-type homomixer (made by Tokushu Kika Kogyo),
By a wire bar coating method, 100 μm thick polyethylene terephthalate (PET) was coated to a dry thickness of 30 μm and dried to prepare a sheet having a release agent absorbing layer.

It was confirmed by microscopic observation that the release agent absorbing layer 95 was formed as a porous layer having voids between spherical particles, as shown in FIG.

The obtained sheet was mounted on a transfer drum shown in FIG. 6 as a transfer sheet which is a transfer material carrying member 93, and a double-sided copying experiment was conducted using a multicolor electrophotographic copying apparatus as shown in FIG. .

First, when the transfer amount of the silicone oil, which is a release agent, to the transfer material in the fixing device was set to 0.05 g per A4 size sheet and double-sided copying was performed, a good image was obtained from the first sheet. When the original was changed and the second copy was taken, a good image was obtained, and during the double-sided copy of the first copy, the silicone oil, which is a release agent, was transferred from the transfer sheet to the photosensitive drum. No phenomenon was observed.

As a result of repeating the double-sided copying operation for 30,000 sheets, a good image free from image stains and fog due to transfer of silicone oil to the photosensitive drum was obtained.

Furthermore, when the transfer amount of silicone oil to the transfer material was set to 0.08 g per A4 size sheet and the same experiment was conducted, a good image was obtained even if the double sided copying operation was repeated for 20,000 sheets. Was given.

When the transfer sheet according to the present invention after the durability test was examined, it was confirmed that the silicone oil was effectively absorbed and accumulated and retained in the voids between the spherical particles.

Example 2 In this example, glass beads having an average particle size of 4 μm were used as spherical particles, and a polyester resin was used as a binder resin, and dried on 100 μm thick polyethylene terephthalate as in Example 1. Of 25 μm was applied to prepare a transfer sheet provided with a release agent absorbing layer.

Using this transfer sheet, the same experiment as in Example 1 was carried out. As a result, similar to Example 1, the transfer amount of silicone oil to the transfer material was set to 0.08 g per A4 size sheet. In addition, even if the double-sided copying operation is repeated 20,000 times, a good image without image stains and fogging due to silicone oil can be obtained, and the silicone oil is quickly absorbed and retained in the release agent absorbing layer of the transfer sheet. It was confirmed that it was not transferred onto the photosensitive drum.

(Example 3) In this example, as the spherical particles, a spherical silicone resin fine powder having an average particle size of 2 μm (Toshiba Silicone Co., Ltd., trade name "Tospearl 120") is used.
In the same manner as in Example 1 except that was used, a release agent absorbing layer having a dry thickness of 40 μm was coated on 100 μm thick polyethylene terephthalate to obtain a transfer sheet.

Using this transfer sheet, a double-sided copy experiment was conducted in the same manner as in Example 1. Even if the transfer amount of silicone oil to the transfer material was set to 0.08 g per A4 size sheet, double-sided copying was performed. Even if the copying operation was repeated 30,000 times, a good image free from image stains and fogging due to silicone oil was obtained, and the same effects as those of the above-mentioned examples were confirmed.

(Embodiment 4) FIG. 2 shows a sectional view of a transfer sheet 93 which is another embodiment of a transfer material carrying member according to the present invention.

In FIG. 2, reference numeral 94 is a dielectric sheet which is a substrate, and as in the case of Example 1, polyethylene terephthalate (PET) polyamide, polyimide,
Polyvinylidene fluoride (Pvdf) or urethane resin, or a sheet in which carbon, fine metal powder or the like is dispersed in these resins to control the volume resistivity, and having a thickness of about 75 μm to 300 μm is mechanical. It can be advantageously used including strength. Reference numeral 95 is a release agent absorbing layer containing spherical particles, which is preferable in terms of release agent absorbability.
Similar to that used in the example shown in FIG. 1 with a thickness of μm to 50 μm.

Reference numeral 96 is a base 94 and a release agent absorbing layer 95.
It is a release agent holding layer containing spherical particles, which is provided between and, and a thickness of 3 μm to 30 μm is preferable from the viewpoint of release agent holding ability. In this example, spherical silica particles having an average particle size of 0.5 μm were used as the spherical particles of the release agent holding layer.

Silicon acrylic resin is used as the binder resin, and the amount used is 10 to 4 relative to the total amount of the particles.
It was prepared in the range of 0 wt%.

In this case, the mixing ratio with the binder is such that if the amount of the binder used is too small, the particles cannot be sufficiently bound on the substrate 94. It is not preferable because a sufficient space for holding the mold agent cannot be maintained and the release agent holding ability is significantly reduced.

The above-prepared mixture was dispersed by a ball mill for 10 minutes to obtain a coating solution, and a 100 μm thick polyethylene terephthalate (PE was prepared by a wire bar coating method.
On T), the release agent holding layer 96 was formed by coating and drying so that the dry thickness was 20 μm.

It was confirmed by microscopic observation that the release agent holding layer 96 was formed as a porous layer having many fine voids between spherical particles, as shown in FIG.

Further, silica spherical particles having an average particle diameter of 2 μm were used as the spherical particles of the release agent absorbing layer of this example, and the adhesiveness with the binder of the lower release agent holding layer 96 was considered as the binder. Then, a silicon acrylic resin was used to prepare a mixture at a mixing ratio of 30 wt%. The obtained mixture is dispersed with a homogenizer (stirrer) for 3 minutes to obtain a coating solution, and the release agent holding layer 9 is prepared by an air spray coating method.
On the polyethylene terephthalate sheet provided with No. 6, a release agent absorbing layer 95 was formed by coating so as to have a dry thickness of 15 μm and drying.

The release agent absorbing layer 95 is observed by a microscope, and the release agent holding layer 96 is formed between the spherical particles as shown in FIG.
Was formed as a porous layer having a large number of voids larger than those present in.

These voids have the following effects with respect to the silicone oil (which is the same with other oils) which is a release agent.

The silicone oil absorbed in the relatively large voids present in the releasing agent absorbing layer 95 migrates to the smaller voids present in the releasing agent retaining layer 96 present in the lower layer by capillary action, and is transferred here. Absorbed and retained.

The obtained sheet is mounted on the transfer drum shown in FIG. 6 as a transfer sheet which is the transfer material carrying member 93, and a double-sided copying experiment is carried out using a multicolor electrophotographic copying apparatus as shown in FIG. did.

First, the transfer amount of silicone oil, which is a release agent, to the transfer material in the fixing device is set to A4 size per one sheet.
When double-sided copying was performed at 0.05 g, a good image was obtained from the first sheet, and when the original was changed and a second copy was made, a good image was obtained. During double-sided copying, no phenomenon was observed in which the silicone oil, which is a release agent, was transferred from the transfer sheet to the photosensitive drum.

Further, as a result of repeating the double-sided copying operation for 30,000 sheets, a good image without image stains and fog due to transfer of silicone oil to the photosensitive drum was obtained.

Further, the transfer amount of the silicone oil to the transfer material was set to 0.08 g per A4 size sheet, and a similar experiment was conducted. As a result, a good image was obtained even after repeating the double-sided copying operation for 20,000 sheets. It was

When the transfer sheet according to the present invention after running was examined, it was confirmed that the silicone oil was effectively accumulated and retained in the voids between the spherical particles of the release agent retaining layer.

Example 5 In this example, spherical spherical particles having an average particle size of 0.4 μm were used as spherical particles dispersed in the release agent holding layer 96, and styrene acrylic resin was used as a binder resin. 10 as in Example 4
2 μm dry thickness on 0 μm thick polyethylene terephthalate
It was coated so that the thickness was 5 μm.

Further, a spherical glass bead having an average particle diameter of 4 μm was used, and a polyester resin was used as a binder resin.
A transfer sheet having the release agent holding layer 96 and the release agent absorbing layer 95 was prepared by coating the polyethylene terephthalate sheet provided with the release agent holding layer 96 so as to have a dry thickness of 15 μm.

Using this transfer sheet, the same experiment as in Example 4 was carried out. As a result, as in Example 4, the transfer amount of silicone oil to the transfer material was set to 0.08 g per A4 size sheet. In addition, even if the double-sided copy operation is repeated for 20,000 sheets, a good image without image stains and fogging due to silicone oil can be obtained, and the silicone oil is quickly absorbed from the transfer material into the release agent absorption layer and the holding layer of the transfer sheet. Retained,
It was confirmed that it was not transferred onto the photosensitive drum.

Example 6 In this example, the spherical particles dispersed in the release agent holding layer 96 had an average particle size of 2 μm.
Spherical spherical silicone resin fine powder (TOSPEARL 120 manufactured by Toshiba Silicone Co., Ltd.) was used, and epoxy resin was used as a binder resin. As in Example 1, it was coated on polyethylene terephthalate having a thickness of 100 µm to a dry thickness of 20 µm. Then, the release agent holding layer 96 was formed.

Further, spherical glass beads having an average particle diameter of 4 μm were used, and polyester resin was used as a binder resin, by the same air spray coating method as in Example 4.
The transfer sheet having the release agent retaining layer 96 and the release agent absorbing layer 95 was prepared by coating the polyethylene terephthalate sheet provided with the release agent retaining layer 96 to a dry thickness of 15 μm. .

Using this transfer sheet, a double-sided copy experiment was carried out in the same manner as in Example 4. As a result, even if the transfer amount of silicone oil to the transfer material was set to 0.08 g per A4 size sheet, double-sided copying was performed. Even if the copying operation was repeated 30,000 times, a good image free from image stains and fogging due to silicone oil was obtained, and the same effects as those of the above-mentioned examples were confirmed.

In order to enhance the adhesiveness between the release agent holding layer 96 or the release agent absorbing layer 95 and the substrate 94, including the above-mentioned respective embodiments, it is not necessary to provide a conventionally known adhesive resin layer in the present invention. It is not something that can be prevented and can be implemented as appropriate.

The toner, which is the developer used in the multicolor electrophotographic copying apparatus shown in FIG. 5, to which the image forming apparatus of the present invention obtained in each of the above-described embodiments is applied, will be described. .

In forming a full-color image, the color reproduction range of the copy can be widened by using a sharp melt toner.

As the toner, a binder resin such as polyester resin or styrene-acrylic ester resin, a colorant (dye, sublimable dye), and a toner-forming material such as a charge control agent are melt-kneaded, pulverized, and classified. It is manufactured by If necessary, an external addition step of adding various external additives (for example, hydrophobic colloidal silica) to the toner may be added.

Considering the fixing property and the sharp melt property, the color toner using the polyester resin as the binder resin is particularly preferable. As the sharp melt polyester resin, a polymer compound having an ester bond in the main chain of a molecule synthesized from a diol compound and a dicarboxylic acid is exemplified.

In particular, the following equation

[0068]

Embedded image (In the formula, R is an ethylene or propylene group, x,
Each y is a positive integer of 1 or more, and the average value of x + y is 2 to 10. ), A bisphenol derivative represented by the formula (1) or a substituted product thereof is used as a diol component, and a carboxylic acid component consisting of a divalent or higher carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof (for example, fumaric acid, maleic acid, maleic anhydride, A polyester resin which is at least copolycondensed with phthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc. is preferable because it has sharp melting characteristics.

The softening point of the polyester resin is 75 to 15
The temperature is 0 ° C, preferably 80 to 120 ° C. The softening characteristics of the toner containing the polyester resin as the binder resin are shown in FIG. The method of measuring the softening point in the present invention will be described below.

A flow tester (CFT-500A type, manufactured by Shimadzu Corporation) was used, and the diameter of the die (nozzle) was 0.2 m.
m, thickness 1.0 mm, 20 kg of extrusion load is applied,
After preheating at an initial set temperature of 70 ° C. for 300 seconds and then raising the temperature at a constant rate of 6 ° C./min, a plunger drop amount-temperature curve (hereinafter referred to as a softened S-shaped curve) of the drawn toner is obtained.
As the sample toner, fine powder obtained by precisely weighing 1 to 3 g is used, and the cross-sectional area of the plunger is 10 cm ² . The softened S-shaped curve becomes a curve as shown in FIG. As the temperature rises at a constant rate, the toner is gradually heated and begins to flow (plunger descending A → B). When the temperature is further raised, the toner in the molten state largely flows out (B → C → D), and the plunger lowering is stopped and completed (D → E).

The height H of the S-shaped curve indicates the total outflow amount, and H /
The temperature T ₀ corresponding to the 2C point indicates the softening point of the sample (for example, toner or resin).

Whether or not the toner and the binder resin have a sharp melting property can be determined by measuring the apparent melt viscosity of the toner or the binder resin.

In the present specification, a toner or a binder resin having a sharp melt property is T ₁ when the apparent melt viscosity shows 10 ³ poise, and T when the apparent melt viscosity shows 5 × 10 ² poise. ₂ means that the condition of T ₁ = 90 to 150 ° C. | ΔT | = | T ₁ −T ₂ | = 5 to 20 ° C. is satisfied.

The sharp-melting resin having these temperature-melt viscosity characteristics is characterized by extremely sharply decreasing the viscosity when heated. Such a decrease in viscosity causes the uppermost toner layer and the lowermost toner layer to be appropriately mixed, and further, the transparency of the toner layer itself is sharply increased, and good subtractive color mixing is caused.

Such a sharp melt color toner has a large affinity and is easily offset at the time of fixing.

Details of the fixing device 17 to which the image forming apparatus of the present invention shown in FIGS. 1 and 2 is applied will be described with reference to FIG.

In FIG. 4, 21 is a fixing roller, which is an HTV on the outer peripheral surface of an aluminum cored bar 22.
Silicone rubber (high temperature vulcanizing type silicone rubber) layer 2
3 is coated with a predetermined thickness, and further an LTV silicone rubber (low temperature vulcanization type silicone rubber) layer 24 is coated on the outer layer thereof with a thickness of 200 μm, and the entire rubber layer is 3 mm.
It is configured to be thick. A pressure roller 25 is provided below the fixing roller 21, and the pressure roller 25 covers the outer peripheral surface of an aluminum cored bar 26 with an HTV silicone rubber layer 27 with a thickness of 1 mm. Further, the surface layer thereof is covered with a resin film 27 '. The fixing roller 21 and the pressure roller 25
Inside each, a 400 W halogen heater 28, which is a heating source, is arranged. Then, a thermistor 29 is brought into contact with the pressure roller 25, and this thermistor 29 controls ON / OFF of current supply to the halogen heater 28. In this way, the fixing roller 21 and the pressure roller 2
The surface temperature of No. 5 is a predetermined value suitable for fixing the unfixed toner image 51 on the transfer material 50 on the transfer material 50 (for example, 1
The temperature is maintained at 70 ° C. The fixing roller 21 and the pressure roller 25 are rotationally driven in the direction of arrow b in the drawing by a driving device (not shown).

On the other hand, in order to improve the releasability of the toner from the fixing roller 21, a releasing agent applying device 52 is provided at a predetermined position of the fixing device 17. This mold release agent applying device 52 includes a silicone oil 53 in an oil tank 52a.
(For example, dimethyl silicone oil manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KF96 300CS”) is pumped up by the roller groups 54 and 55, and the pumped silicone oil 53 is regulated to a fixed amount by the coating amount adjusting blade 40, and then the fixing roller 21. It is configured to be applied to.

The coating roller 55 is the plunger 42.
And a spring 43 to contact and separate from the fixing roller 21.

In general, the amount of silicone oil applied is determined as follows: 50 A4 size transfer materials (white paper) are weighed as A ₁ g, and the image is transferred onto this transfer material. Without applying silicone oil to the offset prevention layer of the fixing roller, the weight of 50 sheets of the transfer material (white paper) after passing between the fixing roller and the pressure roller is set to Bg, and another A4 size transfer material (blank paper)
The weight of 50 sheets is set to A ₂ g, and the image is not transferred onto the transfer material, but silicone oil is applied to the offset prevention layer of the fixing roller, and the toner is passed between the fixing roller and the pressure roller. Assuming that the weight of 50 sheets of the transfer material (white paper) after printing is Cg, the application amount xg of the silicone oil per A4 size transfer material (white paper) is calculated by the following formula. x = (C + A ₁ −B−A ₂ ) / 50 In this fixing device, in order to fix the color and sharp melt toners described above and release the toner that easily causes such offset, x ≈0.1 g of release agent is applied.

Particularly, in the case of a fixing device in a color image forming apparatus, since M, C, Y and BK of a plurality of layers of toner are formed on a transfer material, offset is particularly likely to occur.

Here, the roller 35 comes into contact with the fixing roller 21 and applies a release agent, and the rotation of the fixing roller 21 causes the release agent to come into contact with the fixing roller 21 and the pressure roller 25, that is, the nip portion 58. However, the timing for applying the release agent to the fixing roller is the fixing roller 2
Timing control is performed so that the front end of the release agent applied on 1 reaches the nip earlier than the transfer material enters the nip.

[0083]

According to the present invention as described above,
By providing the release agent absorbing layer containing spherical particles on the surface layer of the transfer sheet, the silicone oil transferred from the transfer material to the second side of the double-sided copy operation can be quickly absorbed and held. Through this, the transfer of silicone oil to the photosensitive drum can be prevented, and the effect of preventing image stains, fog, etc. due to the adhesion of silicone oil is obtained.

Further, when a release agent holding layer containing spherical particles is provided between the substrate and the release agent absorbing layer, the above effect is further improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a transfer sheet used in an image forming apparatus according to an exemplary embodiment of the present invention.

FIG. 2 is a sectional view of a transfer sheet used in an image forming apparatus according to another embodiment of the present invention.

FIG. 3 is a graph showing a softening characteristic of a general toner.

FIG. 4 is a sectional view showing a fixing device of a general multicolor electrophotographic copying apparatus to which the image forming apparatus of the present invention can be applied.

FIG. 5 is a sectional view of a general multicolor electrophotographic copying apparatus to which the image forming apparatus of the present invention can be applied.

6 is a perspective view showing a transfer device of the multicolor electrophotographic copying machine shown in FIG.

[Explanation of symbols]

 93 Transfer Sheet 94 Base 95 Releasing Agent Absorbing Layer 96 Releasing Agent Holding Layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeo Tsunami 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-59-53872 (JP, A) JP-A-62 -299874 (JP, A) JP-A-3-51871 (JP, A)

Claims (8)

[Claims] 1. An image carrier on which a toner image is formed, a transfer material carrier member that holds and conveys a transfer material, a transfer unit that transfers the toner image on the image carrier to the transfer material, and a mold release. In an image forming apparatus including a fixing unit that applies at least pressure and heat to a toner image transferred to the transfer material by a fixing rotator coated with an agent to fix the toner image, the transfer material supporting member is a base member. An image forming apparatus comprising: a release agent absorbing layer which is provided on the surface of the base and absorbs the release agent. 2. The image forming apparatus according to claim 1, wherein the release agent absorbing layer is a layer containing spherical particles on the substrate or a layer containing aggregates of spherical particles. 3. An image carrier on which a toner image is formed, a transfer material carrier member that holds and conveys a transfer material, a transfer unit that transfers the toner image on the image carrier to the transfer material, and a mold release. In an image forming apparatus including a fixing unit that applies at least pressure and heat to a toner image transferred to the transfer material by a fixing rotator coated with an agent to fix the toner image, the transfer material supporting member is a base member. A release agent absorbing layer which is provided on the surface of the base and absorbs the release agent, and a release agent holding layer which is provided between the base and the release agent absorbing layer. An image forming apparatus characterized by the above. Wherein said release agent absorbing layer and a release agent holding layer, according to claim 3, characterized in that a layer containing layers, or aggregates of spherical particles comprising spherical particles on the substrate Image forming device. 5. The image forming apparatus according to claim 4 , wherein the spherical particles contained in the release agent holding layer have a smaller particle diameter than the spherical particles contained in the release agent absorbing layer. . 6. The method of claim wherein the release agent holding layer, characterized in that provided in the lower layer of the releasing agent absorber layer 3-5
The image forming apparatus according to claim 1. 7. An image carrier on which a toner image is formed, a transfer material carrier member that holds and conveys a transfer material, transfer means for transferring the toner image on the image carrier to the transfer material, and a release agent. Used as the transfer material carrying member in an image forming apparatus provided with a fixing unit that applies at least pressure and heat to a toner image transferred onto the transfer material by a fixing rotating body to which is applied. A transfer material carrying member comprising a base and a release agent absorbing layer which is provided on the surface of the base and absorbs the release agent. 8. An image carrier on which a toner image is formed, a transfer material carrier member that holds and conveys a transfer material, transfer means for transferring the toner image on the image carrier to the transfer material, and a release agent. Used as the transfer material carrying member in an image forming apparatus provided with a fixing unit that applies at least pressure and heat to a toner image transferred onto the transfer material by a fixing rotating body to which is applied. Which is composed of a base, a release agent holding layer which holds the release agent and is provided on the surface of the base, and a release agent absorbing layer which is provided on the release agent holding layer. The transfer material carrying member is characterized in that.