JP2001201884A - Image-forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique by which the jamming of a recording material and defective feed are reduced and the fixing property is superior in an electrostatic system image forming method, including the fixing of a toner image by a belt-fixing system whose power consumption is reduced and by which offsetting developing will not be caused. SOLUTION: In an image-forming method, including a fixing method to thermally fix the toner image on the recording material by a heating body and a pressing member to press-fix the recording material to the heating body via a film material by bringing it into press-contact and rotating while being opposed to the heating body after finishing developing and transfer by using a developer, the Bekk smoothness of the recording material is set at 30-10,000 seconds and also the ash content is set at 1-40%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording material for developing an electrostatic image and an image forming method used in electrophotography, electrostatic recording, electrostatic printing, and the like.

[0002]

2. Description of the Related Art Conventionally, as a means for fixing a toner image on a recording material, which is capable of quick start and requires less power during standby, and which has an energy saving effect, a fixedly installed heater and a heater opposed to the heater are known. There is a fixing method in which a toner image is heated and fixed on a recording material by a pressing member which presses and rotates the recording material against the heating member via a film material by pressing and rotating (for example, JP-A-63-313182). As a problem of this fixing method, since the fixing film material is driven by being pressed against the heating element, a jam at the fixing nip is likely to occur due to adhesiveness with the recording material. In addition, fixing defects such as offset and smear due to instantaneous heating through the film material are likely to occur. In addition, the film is likely to be shifted laterally, and poor transportability is likely to occur. Further, there is a disadvantage that the fixing speed is slow because of the use of a thin and low heat capacity film material. Further, when paper is used as the recording material, paper is likely to be generated due to friction with a film material having low hardness, and troubles such as poor conveyance, poor fixing, and offset in a copying machine and a printer often occur. Further, when a toner recycling system is employed, toner and paper are aggregated in the recycling process, and troubles such as jam, conveyance failure, and fixing failure are more likely to occur.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a technique for fixing a film through a film material, which is capable of fixing at a low temperature with energy saving, has excellent offset resistance, and has few jams and conveyance defects. is there.

[0004]

According to the structure of the present invention, which achieves the above object of the present invention, after a developing step and a transferring step are completed by using a developer, a heating element fixed and installed, A pressurizing member that heats and fixes the toner image on the recording material by a pressing member that presses and rotates the recording material and presses the recording material against the heating member via a film material. Degree is 30 to 10,000 seconds and ash content is 1 to
This is an image forming method characterized by being 40%.

Further, in the above image forming method, a cleaning step of cleaning the toner remaining on the surface of the photoreceptor after the transfer step with a cleaning blade and a toner recycling system for supplying the cleaned toner to the developing unit again are adopted. It is assumed that.

Further, the recording material has a surface electrical resistivity described in JIS K6911 of 1 × 10 ⁸ to 1 × 10 ¹³ Ω.

[0007] Further, the recording material is made of paper selected from plain paper, coated paper and processed paper.

[0008] Further, an image receiving layer containing a resin is provided on one surface of the recording material.

(Function) In order to perform stable image formation with low energy consumption, low-temperature fixability, excellent offset resistance, little jam and poor fixing, the surface smoothness, ash content, and surface electric resistance of the recording material are required. By improving the above, the object of the present invention can be achieved.

That is, by using a recording material having a Beck smoothness of 30 to 10,000 seconds and an ash content of 1 to 40%,
The above effects are achieved. The reason is Beck smoothness
The printing quality itself is good with a relatively coarse recording material of less than 30 seconds, but there is a problem that the texture as the recording material is rough and poor, and a jam is likely to occur. Further, when a recording material having extremely smoothness of 10,000 seconds or more is used, there is a problem that the fixing property of the toner is deteriorated. In 30 to 10,000 seconds, the adhesion between the fixing film material and the recording material is good, and the heat transfer is excellent, and the stability of fixing can be improved. Further, since the thermal efficiency is good, it is not necessary to apply excessive heat to the toner, so that the anti-offset property is improved. In addition, fillers (clay, talc, calcium carbonate, etc.) are added at 1 to 40% (weight ratio to pulp) to suppress the hygroscopicity (ratio). The expansion force can be reduced, and the running of the fixing film is stabilized.

Next, the configuration of the present invention will be described in detail.

As described above, the recording material of the present invention needs to have a Beck smoothness of 30 to 10,000 seconds and an ash content of 1 to 40%. If the smoothness is less than 30 seconds, the surface becomes rough when touched by hand, and the texture becomes poor, and the density uniformity and the mottle decrease in the portion where the amount of toner adhesion is large. Also, jams are likely to occur. On the other hand, if the smoothness exceeds 10,000 seconds, the void force on the surface of the recording material is low, and consequently, conveyance failure such as paper supply and paper discharge failure and fixing failure occur, which is not preferable.

The lower the ash content, the higher the hardness. However, the ash content needs to be 1 to 40% in order to obtain a recording material which is white, has little show-through of a printed image, and has no roughness in a halftone area. If it is less than 1%, the hardness is high, but the surface property is deteriorated and the resolution of the copy image and the print image is reduced. Jams are also likely to occur. If it exceeds 40%, the surface of the recording material (smoothness) is improved because the filler fills the voids on the surface of the recording material, but the ratio of the filler increases (the Clark hardness of the recording material increases). ) Is reduced and transport failure is likely to occur.

Further, it is desirable that the smoothness of the recording material is in the range of 35 to 5000 seconds and the ash content is in the range of 2.5 to 30% by weight.

When a cleaning step of cleaning the toner remaining on the surface of the photoreceptor after the transfer step with a cleaning blade and a toner recycling system for supplying the cleaned toner to the developing unit again are employed, recording of paper and the like in the toner is performed. Jamming is likely to occur due to the mixture of the material surface peeling material, but the above-mentioned Beck smoothness is 30 to 10,000
By using a recording material that has a second and an ash content of 1 to 40%, it is possible to suppress the occurrence of paper content and the like, and it is possible to avoid jams and poor transportability.

Further, the surface electrical resistivity of the recording material is 1 × 10⁸Ω
If it is less than 80% RH, the toner
Transfer efficiency decreases, and the print density decreases. 1 × 10^1
ThreeWhen the resistance exceeds Ω, the image circumference is
Toner scatters on the sides and background stains occur.

Further, the recording material can be made of paper selected from plain paper, coated paper and processed paper.
Specifically, chemical pulp, waste paper pulp and the like can be used.
As the chemical pulp, for example, hardwood bleached kraft pulp, hardwood unbleached kraft pulp, hardwood bleached sulphite pulp, softwood bleached kraft pulp, softwood unbleached kraft pulp, softwood bleached sulphite pulp, wood and other fiber raw materials such as soda pulp Virgin bleached chemical pulp that has been chemically treated and made through a bleaching process is preferred, and those with high whiteness are more preferred. In addition, as the used paper pulp, for example, unprinted used paper such as bookbinding, a printing plant, a cutting paper, a waste paper which is generated in a cutting shop, etc. Waste paper pulp, high quality paper, high quality coated paper, medium quality paper, medium quality coated paper, reprinted paper, flat plate, letterpress and intaglio printing, electrophotography, heat-sensitive,
Waste paper pulp printed with thermal transfer method, pressure-sensitive recording paper, ink jet recording method, carbon paper, etc., and aqueous,
Used paper pulp written with oil-based ink or pencil, used paper pulp disassembled from used newspaper after dissociation, used paper pulp deinked by an optimal method for each used paper, lithographically printed waste paper pulp that is relatively easy to deink, and among them white Recycled paper pulp having a high degree of contamination and low in impurities is preferred.

Further, by providing an image receiving layer containing a resin on one surface of the recording material, the affinity with the toner can be increased and the fixing stability can be improved. For example, in an image receiving layer containing a modified silicone resin or a curable silicone resin, it is preferable to use another resin together with the modified silicone resin or the curable silicone resin. It is preferable that the resin is of the same type as the image forming material. The resin used together with the modified silicone resin or the curable silicone resin melts together with the image forming material at a fixing temperature, and preferably has a lower melt viscosity than that of the image forming material. Examples of the resin that can be used in the present invention include acrylic resin, methacrylic resin, epoxy resin, polycarbonate resin, polyester resin, styrene resin, styrene-propylene resin, styrene-butadiene resin, styrene-vinyl chloride resin, and styrene-vinyl acetate. Resins, styrene-acrylate resins, styrene-methacrylate resins, and the like.

The fixing film material used in the present invention is not particularly limited, and a thin film material having excellent heat resistance, releasability and durability and generally having a thickness of 100 μm or less, preferably 50 μm or less can be used. For example, polyester, tetrafluoroethylene polymer, polyimide, polyetherimide at least ethylene tetrafluoroethylene copolymer, tetrafluoroethylene hexafluoropropylene copolymer, tetrafluoroethylene perfluoroalkyl vinyl ether copolymer , A single-layer film or a composite layer film of a heat-resistant resin such as a fluororesin such as a tetrafluoroethylene hexafluoropropylene perfluoroalkyl vinyl ether copolymer or the like, for example, PTFE (tetrafluoroethylene resin) on at least the image contact surface side And a release coat layer having a conductive material added thereto in a thickness of 5 to 15 μm.

In the fixing method to which the recording material of the present invention is applied, the recording material is fixedly installed, pressed against and rotated against the heating member, and the recording material is pressed against the heating member via a film material. This is a fixing method in which a toner image is heated and fixed on a recording material by a pressing member to be heated.

[0021] More specifically, the heating element fixedly installed on the gantry of the apparatus is preferably a low heat capacity line, for example, 0.2 to 5.0 mm in thickness, more preferably
A resistance material of 1.3 mm is applied to an alumina substrate having a length of 0.5 to 3.5 mm, a width of 10 to 15 mm, and a length of 240 mm. The current is supplied by changing the pulse width according to the temperature / energy release amount controlled by the temperature sensor, for example, with a pulse waveform of DC 100 V and a cycle of 25 ms. Temperature T1 detected by temperature sensor in low heat capacity linear heating element
Is the surface temperature T2 of the film material facing the resistance material is T1
Temperature. Here, T1 is preferably 140 to 200 ° C, and the temperature of T2 is preferably 0.5 to 10 ° C lower than the temperature of T1. Further, the film material surface temperature T3 at a portion where the film material is separated from the toner fixing surface is substantially equal to T2. The driving of the film material is performed by a driving roller and a driven roller and by a tension in a direction indicated by an arrow K shown in FIG. The pressure roller has a rubber elastic layer having a high release property such as silicon rubber, and is pressed against the heating body via the film material at a total pressure of 2 to 30 kg, and is rotated under pressure.

FIG. 1 shows a schematic configuration of an embodiment of a fixing device used in the above fixing method. In FIG. 1, reference numeral 4 denotes a fixedly installed heating element, which has an alumina substrate 5 and a temperature sensor 6 coated with a resistance material (on the lower side in the figure). The temperature and energy release amount of the alumina substrate are controlled by a control mechanism (not shown). 2 is an endless belt-shaped film material, 1 is a driving roller for driving the film material 2, 3 is a tension roller, and 8 is a pressure roller for pressing the recording material to the heating element 4 via the film material 2. Reference numeral 7 denotes a guide plate for guiding the recording material to the fixing device. The recording material having the toner image moves in the direction of arrow K with the toner image facing the film material 2 and is sent to the fixing device to be fixed.

The main component resin of the toner used in the present invention is not particularly limited, and styrene / acrylic resin, epoxy resin, polyester resin and the like can be used. As the molecular weight distribution, both a single peak distribution and a distribution of two or more peaks are used, and a high molecular weight component having a molecular weight of 400,000 or more and T
The total amount of the HF-insoluble gel is preferably 10% by weight or less of the whole resin. It is more preferably at most 3 wt%, particularly preferably at most 1 wt%.

Examples of the coloring agent include aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow, rhodamine dyes, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dyes, monoazo dyes, disazo dyes, and condensed azo dyes. Any known dyes and pigments such as system dyes and pigments can be used alone or in combination. In the case of a full-color toner, it is preferable to use benzidine yellow, monoazo dyes and condensed azo dyes for yellow, quinacridone, rhodamine dyes and monoazo dyes for magenta, and phthalocyanine blue for cyan. Coloring agents are usually
It is used in an amount of 3 to 20 parts by weight based on 100 parts by weight of the binder resin.

As the charge control agent, any known charge control agent can be used alone or in combination. In the case of a color toner, it is necessary that the charge control agent itself is colorless or light color and there is no color hindrance to the toner, and a quaternary ammonium salt compound is used as the positive charge, and chromium of salicylic acid or alkyl salicylic acid is used as the negative charge. Metal salts with zinc, aluminum, etc., metal complexes, metal salts of benzylic acid,
Preferred are metal complexes, amide compounds, phenol compounds, naphthol compounds and the like. The used amount may be determined based on the desired charge amount of the toner. Usually 100 binder resin
It is preferable to use 0.1 to 10 parts by weight based on parts by weight.

The toner used in the present invention consists essentially of the above-mentioned binder resin, colorant and charge controlling agent, and if desired, may further contain wax and other components. As the wax, any known wax can be used alone or in combination. Specific examples include olefin waxes, particularly preferably low molecular weight polypropylene, paraffin wax, higher fatty acids, fatty acid amides, metal soaps, and the like. The amount used depends on the binder and the colorant, but is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the binder resin.

[0027] As a lubricant, 50 to 130 in DSC measurement
° C, particularly preferably 60 to 120 ° C, more preferably 65 to 9 ° C.
Those having an endothermic peak in the range of 0 ° C. and a half-width value of the endothermic peak of 15 ° C. or less, particularly preferably 10 ° C. or less, are preferred. More preferably, those satisfying the above conditions and having a structure represented by the general formula (1) can be mentioned.

R1-CO-R2 ············· Formula (1) wherein R 1 represents an alkyl group or an alkoxyl group having 10 or more carbon atoms, and R 2 represents —X—COOR 3 (X represents an alkylene R3 represents an alkyl group having 10 or more carbon atoms) or an alkyl group having 10 or more carbon atoms. }

Particularly, the carbon number of R1 is preferably 16 or more, more preferably 20 or more. X in R2 is preferably

-(CH ₂ ) _n-

Wherein n is a straight-chain alkylene group having 6 or more, and the alkyl group of R 3 preferably has 20 or more carbon atoms. Alternatively, when R2 is an alkyl group, it preferably has 16 or more carbon atoms. Particularly preferred is an alkyl group having 20 or more carbon atoms. When R2 is -X-COOR3, R
1 is preferably an alkoxyl group (that is, a diester). Specific examples include di-n-decyl ketone,
Di-n-dodecyl ketone, di-n-stearyl ketone,
Aliphatic ketones such as di-n-icosyl ketone, di-n-behenyl ketone, di-n-tetracosyl ketone; fatty acid diesters such as didodecyl sebacate, distearyl sebacate, dibehenyl sebacate, stearyl laurate; Behenyl laurate, stearyl stearate,
Fatty acid monoesters such as behenyl stearate, stearyl behenate, behenyl behenate and the like can be mentioned.
These mixtures are also suitable, but at this time, it is necessary that the half width value of the endothermic peak of DSC is 15 ° C. or less. Among them, those having a total carbon number of 36 or more in the molecule are particularly preferable, and among the above specific examples, aliphatic ketones are particularly preferable. The amount used depends on the binder and colorant, but 0.5 to 30 parts by weight per 100 parts by weight of the binder resin,
It is preferably 1 to 15 parts by weight, particularly preferably 2 to 10 parts by weight.

[0032] Components other than the above include fluidity improvers such as fine powders of silica, alumina, and titania; inorganic fine powders such as magnetite, ferrite, cerium oxide, strontium titanate, and conductive titania; styrene resins; and acrylic resins. And the like are used as internal additives or external additives. The amount of these additives used may be appropriately selected depending on the desired performance, and is usually preferably about 0.05 to 10% by weight based on 100 parts by weight of the binder resin.

The production of the toner according to the present invention from each of the above-mentioned components can be carried out according to a conventional method for both the pulverization method and the polymerization method. For example, first, a resin, a colorant, a charge control agent, and wax added as needed are uniformly dispersed and mixed by a mixer, and then the mixture is mixed with a closed kneader or a single-screw or twin-screw extruder. After melt-kneading and cooling, it is coarsely crushed with a crusher, hammer mill, etc., finely crushed with a jet mill, high-speed rotor rotary mill, etc., and is classified with an air classifier (eg, elbow jet of inertial classification, microplex of centrifugal classification). , DS separator, etc.).

When the toner is used as a two-component developer in the present invention, the carrier may be a magnetic substance such as iron powder, magnetite powder, or ferrite powder, or a carrier whose surface is coated with a resin or a known carrier such as a magnetic carrier. Can be used. As the coating resin of the resin coating carrier, generally known styrene resin, silicone resin, acrylic resin, styrene acrylic copolymer resin, modified silicone resin, fluorine resin, or a mixture of these resins, etc. Available.

Further, the toner according to the present invention further contains a magnetic material and can be used as a magnetic toner. As the magnetic material contained in the magnetic toner of the present invention, magnetite, hematite, iron oxide such as ferrite, iron, cobalt, metals such as nickel or aluminum of these metals,
Examples include alloys of metals such as cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, and vanadium, and mixtures thereof.

These magnetic materials preferably have an average particle size of about 0.1 to 2 μm, and are contained in the toner in an amount of about 20 to 200 parts by weight, particularly preferably 100 parts by weight, based on 100 parts by weight of the resin component. About 40 to 150 parts by weight.

[0037]

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, parts and% are by weight.

[Production of Recording Material] Example 1 The following production recipe was used. (A) 100% L-BKP with a beating degree of 500 CSF (B) 8% talc (weight ratio to pulp), 1% rosin sizing agent, 5% sulfuric acid band, 0.5 g oxidized starch as a surface sizing agent m ² , NaCl 0.25% Pressing pressure is set as low as 10-40 kg / m ² as much as possible.
Cardboard with a basis weight of 67 g / m ^{2 was} produced at 0 m / min. Product smoothness,
Table 1 shows the ash content and surface electric resistance number characteristics.

Example 2 100 parts by weight of synthetic boehmite sol were added at a polymerization degree of 500 and a degree of saponification.
11 parts by weight of 99 mol% of polyvinyl alcohol was added, and water was further added to prepare a coating solution having a solid concentration of 18% by weight.
The dried coating liquid to wood free paper having a basis weight of 127 g / m ² coating weight 15 g / m
Coating was carried out using a bar coater so as to obtain ² . The water content (moisture / solid content) immediately after coating was 456%. This was dried to reduce the water content to 250%. This was adhered to a mold having a mirror surface heated to 90 ° C. at a linear pressure of 10 kg / cm and dried, and then peeled off to obtain a glossy paper having a glossy coating layer. Table 1 shows the smoothness, ash content, and surface electrical resistance number characteristics of this recording material.

Example 3 10 parts of a polyester resin, 8.6 parts of a silicone polyester varnish (modified silicone resin), and 4.5 parts of titanium oxide as a white pigment, 20 parts of toluene, and sufficiently stirred with a sand mill disperser to form an image receiving layer. A liquid was prepared. This coating solution was dropped on high-quality paper and coated using a bar coater. After coating, the coating was dried at 100 ° C. for 10 minutes to form an image receiving layer on plain paper. Table 1 shows the smoothness, ash content, and surface electric resistance number characteristics of this recording material.

Examples 4 to 6 Using the recording materials of Examples 1 to 3, a toner recycling system was employed. The results are also shown in Table 1.

Comparative Examples 1 to 4 Papers having the same composition as in Example 1 but different physical properties were prepared. Table 1 shows the smoothness, ash content and surface electric resistance number characteristics of this recording material.

The smoothness of the recording material was measured on the front and back of the recording material according to JIS P8119. In addition, the smoothness described in the following Table 1 describes the smoothness of the surface on the printing side of each sample in order to correspond to "roughness" with a printed image.

The ash content of the above recording material was measured with reference to JIS P8128. Test pieces were prepared according to JIS P8128, and 500
The weight W of the residue after burning at 3 ° C. for 3 hours was weighed, and the ratio (W / S) to the mass S of the dried test piece was expressed in percentage.

The surface electric resistance was measured by using a room temperature measuring box (RC-02) and a super insulation meter (R-503) manufactured by Kawaguchi Electric Works, Ltd., and setting the applied voltage to 100 V, according to the method of JIS P8111. The test piece was pre-treated, and each was measured under the same conditions as in the pre-treatment by a method according to the surface resistivity of JIS K6911.

[Evaluation of Actual Machine] The fixing unit of the Ricoh copier MF200 was changed to the fixing device shown in FIG. 1 and modified, and a 1000-sheet print test was performed. , Offset, smear and the like were evaluated. In FIG. 1, reference numeral 1 denotes a driving roller which drives a fixing film 2 suspended around a tension roller 3 or the like. Reference numeral 8 denotes a pressure roller in which a heating element 4 is disposed, and an alumina substrate is provided in the heating element 4.
5 and a temperature sensor 6 are provided. 7 is a paper feed guide,
Feed paper from K. In each of the evaluations, the results are shown in Table 1 as "good", "bad" but usable, and "poor".

[0047]

[Table 1]

Fixing condition: The temperature T1 detected by the sensor 3 is set to 19
0 ° C, fixing film facing resistance material of alumina substrate 5
2, the surface temperature T2 of the fixing film 2 is 176 ° C., and the fixing film surface temperature T3 at a portion where the fixing film 2 is separated from the toner fixing surface.
Was set to 174 ° C.

Film material speed: 150 mm / sec Total pressure between heating body and pressure roll: 15 kg Nip between pressure roller and film material: 3 mm Film agent: Conductive substance-dispersed ethylene tetrafluoroethylene copolymer coated on the surface 15μm polyimide film material Warm-up time: 4 seconds

[0050]

According to the present invention, in an image forming method including a fixing method in which the waiting time of a copying machine is made extremely short, power consumption is low, and an offset phenomenon does not occur, jamming of a recording material and conveyance failure are reduced. , Technology with excellent fixability is provided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an example of a fixing device used in an image forming method of the present invention.

[Explanation of symbols]

 1 Drive roller 2 Fixing film material 3 Tension roller 4 Heating element 5 Alumina substrate 6 Temperature sensor 7 Feed guide 8 Pressure roller

Continued on the front page (72) Inventor Shigeru Emoto 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Mitsuo Aoki 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Hiroto Higuchi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Tsuneshin 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh F-term ( Reference) 2H033 AA14 AA30 AA32 BA08 BA25 BA26 BA30 BB28 BE03

Claims (5)

[Claims] After completion of a developing step and a transferring step using a developer, a fixedly installed heating element is rotated by pressing against the heating element, and a recording material is transferred to the heating element via a film material. In an image forming method including a fixing method of heating and fixing a toner image on the recording material by a pressing member to be pressed, the recording material has a Beck smoothness of 30 to 10,000 seconds and an ash content of 1 to 40%. An image forming method comprising: 2. The image forming method according to claim 1, wherein a cleaning step of cleaning the toner remaining on the surface of the photoreceptor after the transfer step by a cleaning blade and a toner recycling system for supplying the cleaned toner to the developing unit again are adopted. . 3. The image forming method according to claim 1, wherein the recording material has a surface electrical resistivity according to JIS K6911 of 1 × 10 ⁸ to 1 × 10 ¹³ Ω. 4. The image forming method according to claim 1, wherein the recording material is made of paper selected from plain paper, coated paper, and processed paper. 5. The image forming method according to claim 1, wherein an image receiving layer containing a resin is provided on one surface of the recording material.