JPS6162054A - Picture formation method - Google Patents

Abstract

PURPOSE:To form continuously and stably fine pictures on many sheets of transfer paper different in size by forming images with a specific toner and rotating a heat roller increasing its temperature so that the temperature on the end part side is lower than that of the center part at a specific linear speed to heat and fix the toner images. CONSTITUTION:A toner image is formed on a transfer material with toner obtained by containing a releasing agent consisting of wax of which melting point is 60-110 deg.C and melted viscosity at 160 deg.C is <=100cp and other necessary components in binder resin. On the other hand, a heater lamp 1 is turned to the working status and a high temperature area 21 passing small-sized transfer paper and low temperature areas 22, 23 passing both the side ediges of large- sized transfer paper without passing the small-sized transfer paper are formed on the surface of the heat roller. Then the heat roller is rotated at >=180mm/sec linear speed to fix the toner image. Even if pictures are formed on transfer sheets having different size in any order at the time of continuous and rapid picture formation, a winding phenomenon is not generated and fine pictures can be continuously and stably formed many times.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention is an image forming method in which an electrostatic charge image, a magnetic latent image, or the like is visualized with a toner, and the toner image formed thereby is transferred to a transfer paper or the like to obtain an image. This relates to a forming method.

[Prior art]

For example, an image forming method using electrophotography includes a process of forming an electrostatic image on a photosensitive drum, a developing process of visualizing this electrostatic image with toner to form a toner image, and a fixing process of fixing the toner image. In the fixing process, the toner image formed in the developing process may be fixed to the support as is, but usually it is transferred to another support such as transfer paper and then fixed. . Various methods are known for fixing toner images, but the contact heating fixing method using a heat roller is particularly superior in terms of high thermal efficiency, and is capable of high-speed fixing. Suitable for fixing in copying machines.

In a conventional heat fixing device, a rod-shaped lamp lamp is used as a heater for the ill heating roller. The temperature is increased. However, since supporting members and the like are attached to both ends of the heat roller, heat dissipation is greater at the ends than in the center.
Therefore, in consideration of the large heat dissipation at the ends, the heat resistance distribution in the length direction of the heater lamp is such that the amount of heat generated at both ends is larger than that at the center.

Recently, however, there has been an even stronger desire for higher speed copying machines, and with this, there has been a demand for higher speed fixing. In practical terms, for example, in order to form 45 or more copies per minute using A4-sized transfer paper, the linear velocity (hereinafter simply referred to as "linear velocity") of the transfer paper fed by the heat roller during fixing must be adjusted.
That's what it means. ) is required to be at least 180 mm/sec or more.

However, a new problem has been found when high-speed fixing is carried out using a conventional heat roller having built-in heater lamps with a heat-resistant distribution that generates a high amount of heat at both ends. In other words, when high-speed fixing of a toner image transferred to a small-sized transfer paper whose width is shorter than the length of the heat roller is performed many times in succession, the center of the heat roller loses heat to the transfer paper. On the other hand, the temperature at the end of the heat roller accumulates and becomes high because it does not come into contact with the transfer paper.On the other hand, the temperature also decreases at the back-up roller, which is placed opposite to the heat roller. The end portions become hotter, and the temperature difference between the center and end portions of both the heat roller and the backup roller becomes large. If a large temperature difference occurs in the length direction of the heat roller and the hack up roller, the difference in thermal expansion will cause a difference in the linear velocity between the center and the end of the contact area between the heat roller and the hack up roller. This results in the loss of l
・When fixing a Lee image, a phenomenon occurs in which white streaks similar to the arrangement shape of ribs appear (hereinafter referred to as the "Ahara phenomenon") in the resulting fixed image, resulting in the formation of a clear image. I can't.

In order to prevent the occurrence of such a scattering phenomenon, it is conceivable to use a heater lamp having a heat resistance distribution such that the amount of heat generated at the end portions is smaller than that at the center portion. However, in such a method, since the temperature on the edge side of the heated L cola is lower, it is difficult to fix the 1-toner image transferred at high speed on a large size transfer paper that comes into contact with the edge side of the heated roller. If this is done continuously, a so-called wrapping phenomenon occurs in which the transfer paper is adhered to and wrapped around the surface of the heat roller, and as a result, sufficient high-speed fixing cannot be achieved.

[Purpose of the invention]

The present invention has been made based on the above circumstances, and its object is to determine in what order images are formed using transfer paper of different sizes when images are formed continuously at high speed. Even in cases where the fixation is applied, the wrapping phenomenon does not occur and a practically sufficient fixation can be achieved.
An object of the present invention is to provide an image forming method capable of continuously and stably forming good images many times.

[Structure of the invention]

The above purpose is to have a melting point of 60 to 11 in the binder resin.
A toner image is formed using a toner containing wax having a melt viscosity of 100 cp or less at a temperature of 160°C at 0°C. This is achieved by an image forming method characterized in that the toner image is heated and fixed by rotating a thermal roller whose temperature is gradually increased at a linear speed of 180 m/sec or more.

The present invention will be explained in detail below.

In the present invention, a 1-toner image is formed on the transfer material using a specific toner, the details of which will be described later, and when the heater for the heat roller is activated, the temperature on the edge side is lower than the center area. A thermal roller whose temperature is raised is rotated at a linear speed of 180 mm/sec or more to heat and fix the toner image, thereby forming a copy image.

In the above, the transfer material may be any sheet body that has the function of supporting the transferred toner image on its surface and fixing the toner image by a heating roller fixing device, such as paper, plastic sheet, processed sheet. Paper (transfer paper) is preferably used.

The toner used in the present invention contains a binder resin with a melting point of 60 to 110°C and a melt viscosity of 10°C at a temperature of 160°C.
A release agent made of wax having a concentration of 0 cp or less is contained together with other necessary toner components.

In the above, the melting point of the wax is determined by differential scanning calorimetry (DSC). That is, the melting point is defined as the melting peak value when several samples are heated at a constant temperature increase rate (10° C./ml). Further, the melt viscosity of the wax can be measured using, for example, a "B-type viscometer" (Tokyo Keiki Seisaku Kaisha).

When the melting point of the release agent exceeds 110°C, a sufficient release effect cannot be obtained during low-temperature fixing, and on the other hand, when the melting point is lower than 60°C, the toner particles are too sticky. It tends to aggregate and storage stability decreases. Further, in the mold release agent, the melt viscosity at a temperature of 160°C is 100c.
If it exceeds p, the release agent will not fully penetrate the surface of the toner during fixing, resulting in poor fixing.Moreover, if high-speed fixing is performed continuously, a wrapping phenomenon will occur at an early stage, and eventually sufficient fixing will not be achieved. cannot be achieved.

Specific examples of the release agent include those listed in Table 1 below.

Table 1 The content ratio of the mold release agent is 1 to 1 to the binder resin.
Within the range of 20% by weight, preferably 1 to 10% by weight
is within the range of If this proportion is less than 1% by weight, the effect as a release agent is not exhibited, so the non-wrapping property of the toner is not improved, and the effect of lowering the minimum fixing temperature cannot be obtained.

On the other hand, if it exceeds 20% by weight, the fluidity of the toner decreases, resulting in poor developability and transferability, resulting in failure to form a good visible image, and in addition, it may cause problems with development, sleeves, or electrostatic image supports. The mold release agent adheres and forms a film, which inhibits its function.

As the binder resin used in the toner in the present invention, various thermoplastic resins are used.

Specific examples include styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, and methyl methacrylate. , ethyl methacrylate, n-butyl methacrylate, lauryl methacrylate, α-methylene aliphatic monocarboxylic acid esters such as 2-ethylhexyl methacrylate; vinyl nitrile such as acrylonitrile and methacrylonitrile; 24-'nylpyridine, 4- Vinyl pyridines such as vinyl pyridine; Vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; Vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, and methyl isopropenyl ketone; Unsaturated hydrocarbons such as ethylene, propylene, isoprene, and butadiene and their halides, polymers of monomers such as halogen-based unsaturated hydrocarbons such as chloroprene, copolymers obtained by combining two or more of these monomers, and mixtures thereof, or, for example, Non-vinyl condensation resins such as rosin-modified phenol-formalin resins, epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, and polyether resins, or mixtures of these and the above-mentioned vinyl resins can be mentioned. Among these, it contains a high molecular weight component and a low molecular weight component, and the number average molecular weight Mn
The value of the ratio Mw/Mn of the weight average molecular weight Mw to 3.
Styrenic resins having a molecular weight of 5 or more and polyester resins having a chloroborum insoluble content of 5% by weight or more are preferable because they have good fixing properties and non-wrapping properties themselves.

Toner components that may be used as necessary in the toner used in the present invention include, for example, colorants, magnetic substances, and various property improvers.

As a coloring agent, carbon black, nigrosine dye (
C, 1, No. 50415B), Aniline Blue (C,
I.

No. 50405), Calco Oil Blue (C, I,
No, azoecBlue 3), Chrome Yellow (
C, 1, No, 14090), Ultramarine Blue (C, 1, No, 77103), DuPont Oil Red (C, 1, No, 26105), Quinoline Yellow (C, T, No, 47005), Methylene Blue Chloride ( C, 1, No. 52015), Phthalocyanine Blue (C, I.

No. 74160), Malachite Green Oxale
1・(C, 1, No, 42000), lamp black (
C, 1, No. 77266), Rose Hengar (C, 1
, No. 45435), mixtures thereof, and others. These colorants need to be contained in a sufficient proportion to form a visible image with sufficient concentration, and are usually 1 to 2 parts by weight per 100 parts by weight of the binder resin.
0 parts by weight.

The magnetic material may be a metal or alloy that exhibits ferromagnetism such as ferrite, magnetite, iron, cobalt, or nickel, or a compound containing these elements, or a material that does not contain a ferromagnetic element but can be made by subjecting it to appropriate heat treatment. Mention may be made of alloys which become ferromagnetic, such as the type of alloys called Heusler alloys containing manganese and aluminum, such as manganese-copper-aluminium, manganese-copper-tin, or chromium dioxide, among others. . These magnetic substances are uniformly dispersed in the binder in the form of fine powder with an average particle size of 0.1 to 1 micron. And its content is 1
- 20 to 70 parts by weight, preferably 40 to 70 parts by weight per 100 parts by weight of chi.

Examples of the property improving agent include a charge control agent, an anti-offset agent, a lubricant for improving fluidity, and others.

The toner used in the present invention is mixed with a carrier made of iron powder, glass beads, etc. to make a two-component developer, but when it contains a magnetic material, it can be used as a one-component developer for developing electrostatic images. be done.

In the present invention, as described above, when the heat roller heater is activated, the heat roller is heated so that the temperature at the end portion is lower than that at the center portion, and when the toner image is fixed. In the above, the toner images 1 to 1 are fixed while the heat roller is rotated at a linear speed of 180 mm/sec or more.

Specifically, as schematically shown in FIG. 1, for example, the heat generating section is comprised of a high heat generating section 11 with a length corresponding to a small size, and low heat generating sections 12 and 13 located at both ends of the high heat generating section 11. By disposing the heater lamp 1 inside the heat roller 2, on the surface of the heat roller when the heater lamp 1 is activated, there is a high temperature area 21 through which a small size transfer paper passes, and a small size area. Low-temperature area 2 where the transfer paper does not pass through, but both edges of the large size transfer paper pass through.
2.23. 3 is a backup roller.

Practically speaking, it is preferable that the temperature difference between the center and end portions of the surface of the heat roller is always about 30° C. or less.

In one example of the heat roller, a resin layer or a rubber layer is provided on the surface of a cylindrical metal core. In forming this resin layer or rubber layer, it is preferable to use a perfluoroalkoxy resin such as "Teflon" (polytetrafluoroethylene manufactured by DuPont). Because of this, the effect of preventing the wrapping phenomenon is improved.

The heat source for raising the temperature of the heat roller is not particularly limited, and a resistance heating element, a heat radiation lamp, or the like can be used.

〔Effect of the invention〕

Since the present invention is an image forming method as described above, when images are formed continuously at high speed, no matter what order the images are formed using transfer papers of different sizes. No winding phenomenon occurs, and practically sufficient fixing can be achieved, and good images can be stably formed many times in succession.

This effect is achieved because fusing is performed using a heat roller that is heated so that the temperature at the edges is lower than the center when the heater for the heat roller is activated. When images are continuously formed using transfer paper of the same size, the temperature of the central part of the hot roller and the bank up roller facing it decreases considerably compared to the initial stage. Since the initial temperature of the end portions is lower than that of the center portion, even if there is a temperature difference between the center portion and the end portions of each of the heat roller and the backup roller, it is considerably small. Therefore, the linear velocity of the opposing frontal area between the heat roller and the hack-up roller is approximately 20% even for practical use from the center to the end, and therefore, it is assumed that the heat roller will subsequently come into contact with the end side of the heat roller. Even when an image is formed using a large-sized transfer paper, good fixing can be achieved without the Ahara phenomenon occurring in the fixed image obtained. When images are formed continuously at high speed using large-sized transfer paper, even when the temperature drop at the end of the heat roller becomes extremely large, the separation contained in the toner may The molding agent has a melting point of 60 to 110°C and a temperature of 1
Since it is made of wax with a melt viscosity of 100 cp or less at 60°C, the wax component melts even at low temperatures and oozes out onto the surface of the toner, and its tackiness when melted is low, so that the wax covers the entire surface of the toner. As a result, a good mold release effect can be achieved even at low temperatures, and the occurrence of the phenomenon of volume 4 = J can be prevented. This is believed to be because the melting temperature point of the binder resin of the toner shifts to the lower temperature side, and sufficient low-temperature fixability is exhibited.

Since the adhesion of the transfer paper to the heat roller due to toner is small, the transfer paper does not move with the heat roller during fixing and is smoothly separated, so that the transfer paper and the heat roller are easily separated. Since the contact time is shortened and the amount of heat taken from the heat roller to the transfer paper is reduced, the effect of reducing the temperature drop of the heat roller during high-speed copying can also be obtained.

[Embodiments of the invention]

Examples of the present invention will be described below, but the present invention is not limited thereto. Note that "1 part" represents parts by weight.

Example 1 (Production of binder resin) 299 g of terephthalic acid and polyoxypropylene (2,
2) 211 g of -2,2-bis(4-hydroxyphenyl)propane and 82 g of pentaerythritol were placed in a round tube equipped with a thermometer, a stainless steel stirrer, a glass nitrogen gas inlet tube, and a down-flow condenser. Place it in a bottom flask, set this flask on a mantle heater, introduce nitrogen gas from the nitrogen gas introduction tube to raise the temperature while keeping the inside of the flask in an inert atmosphere, and then add 0.05 g.
dibutyltin oxide was added thereto, and the reaction was carried out at a temperature of 200°C while monitoring the reaction at the softening point to obtain a polyester resin with a chloroform insoluble content of 17% by weight and a softening point of 131°C. This will be referred to as "binder resin A."

(Manufacture of toner) Binder resin A 100 parts Release agent "Rice Wax F-1" (manufactured by Noda Wax Co., Ltd., melting point near 9°C, melt viscosity at 1160°C: 6 cp) 3 parts Carbon blank "
Mogul L" (manufactured by Cabosoto) 10 parts or more of the material was kneaded using an Ex-I Ruder, cooled, crushed, and classified to obtain I-ner consisting of particle powder with an average particle size of 1011 m.

Next, this toner was mixed with a resin-coated carrier made of iron powder to prepare a developer having a toner concentration of 2% by weight.

Next, length 470mm, diameter 40mm, wall thickness 10mm
Inside the cylinder of the heat roller, which is constructed by providing a perfluoroalkoxy resin coating on the surface of the cylindrical aluminum core metal,
An electrophotographic copying machine [U-old x 4500J (Konishi Roku) which has a toner paste cycle system has a fixing device configured with a built-in heater lamp that generates heat distribution as shown in Figure 2 for the heat roller. (manufactured by Photo Industry Co., Ltd.), the linear speed of the heat roller was adjusted to 210 mm/sec, and the above developer was used to develop an electrostatic image and toner image onto transfer paper under an environmental condition at a temperature of 10°C. We conducted a live-action test using the process of transferring and fixing the toner image using a heat roller fixing device.
When the test was performed 300 times using B5 size transfer paper and then 300 times using A3 size transfer paper, no looseness occurred, and no wrapping phenomenon occurred. A stable and excellent fixed image was obtained.

During this live-action test period, we measured the surface temperatures of the heat roller and hack-up roller, and as shown in Figure 3, there was a small temperature difference between the center and end of each of the heat roller and hack-up roller. The temperature drop was relatively gradual, and even after 600 copies, the temperature was still sufficient for practical use.

Example 2 In Example 1, "Candle Wax No. 2" (manufactured by Noda Wax Co., Ltd., melting point: 64°C, melt viscosity at 160°C: 2 cp) was used instead of [Rice Wax F-1].
A developer was prepared in the same manner except for using
Moreover, no curling phenomenon occurred, and a fixed image that was stably crooked until the end was obtained.

During this live-action test period, we measured the surface temperatures of the heat roller and hack-up roller, and as shown in Figure 3, there was a small temperature difference between the center and end of each of the heat roller and hack-up roller. The temperature decreased relatively slowly, and even after 600 copies, the temperature was still sufficient for practical use.

Comparative Example 1 A photocopying test was conducted in the same manner as in Example I except that the heater lamp was replaced with a heater lamp that generated heat distribution as shown in FIG. 4 with respect to the heat roller. During the period of 400 times, the Ahara phenomenon occurred continuously in the copied images, and the image quality deteriorated significantly. Also, during this live-action test I, the surface temperature of the heat roller and backup roller was measured.
As shown in the figure, there was a large temperature difference between the edges and the center.

Comparative Example 2 In Example 1, instead of [Rice Wax F-1], "Mitsui Hiwax 400PJ (manufactured by Mitsui Petrochemicals, melting point: 126°C, melt viscosity at 160°C: 2350
When a developer was prepared in the same manner except that cp) was used and a photocopying test was conducted in the same manner, the number of copies was 450.
After the first round, the phenomenon of winding occurred frequently in wholesalers. In addition, when we measured the surface temperature of the heat roller and hack-up roller during this actual copying test period, as shown in Figure 6, after 300 copies were made, the temperature at the end of the heat roller decreased rapidly, resulting in early fixation. It became insufficient.

[Brief explanation of drawings]

FIG. 1 is an explanatory cross-sectional view schematically showing an example of a fixing device, and FIGS. 2 and 4 are curve diagrams showing the heat generation distribution of the heater lamp to the heat roller used for the live-action test in the example and comparative example, respectively. , FIG. 3, FIG. 5, and FIG. 6 show the number of copies of the surface temperature at the center and end of each of the heat roller and backup roller during the actual copying test period in Example 1, Comparative Example 1, and Comparative Example 2, respectively. FIG. 3 is a curve diagram showing changes over time. ■...Heater lamp 2...Heat roller 3...Backup roller 11...High heat generation part 12.13...Low heat generation part Procedure amendment (method) February 1985 l Kennichi Patent Office Director Manabu Shiga1, Indication of the case Patent Application No. 183686 of 19832, Name of the invention Image forming method 3, Relationship with the person making the amendment Patent applicant address 1-26 Nishi-Shinjuku, Shinjuku-ku, Tokyo No. 2 Name (127) Roku Konishi Photo Industry Co., Ltd. 4, Agent January 29, 1985 6, Subject of amendment 7, Contents of amendment 1) A copy of the engraving of the specification and attached sheet originally attached to the application. As per (no change in content) 2) As shown in the engraving of the drawing originally attached to the application form/attached sheet
(No change in content)

Claims (1)

[Claims] 1) Forming a toner image using a toner containing a wax having a melting point of 60 to 110°C and a melt viscosity of 100 cp or less at a temperature of 160°C in a binder resin,
When the heat roller heater is activated, the temperature of the heat roller is raised so that the temperature at the end is lower than that at the center.
An image forming method characterized by heating and fixing the toner image by rotating at a linear speed of 80 mm/sec or more.