JPH04221968A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the diffusion of volatile component generated at the time of fixing developer and to prevent the contamination of a corona charger and the irregularities in a latent image. CONSTITUTION:In a heating and fixing device, an adsorbent carrying member 13 is applied in the heat insulating cover 12 of the fixing device and it is applied near the fixing device, for example, in the paper ejecting part 39 of a main body frame, so that a situation that a user has a smell caused by the evaporation of the volatile component of the developer by heating is prevented. In the case that a means for applying a releasing agent to a fixing roller is provided, a situation that the volatile component of a releasing agent adheres to a corona charge line and a photosensitive drum in a latent image forming part to deteriorate the image is also prevented in such constitution. Activated carbon, activated alumina, silica gel, or porous glass, for example, which is fitted for the developer and the releasing agent is selected as the adsorbent.

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 equipped with a heat fixing device such as an electrophotographic copying machine or a printer.

0002

2. Description of the Related Art Conventionally, as shown in FIG. 3, an image forming apparatus applying electrophotography, such as a printer, rotates a photosensitive drum 21, which has a photosensitive layer provided on the top surface of a conductive cylinder made of aluminum, in the direction of the arrow, and is charged by a corona charger 22. Uniformly charged,
An image signal is applied to a laser diode 23, and an exposure device consisting of a combination of a polygon mirror 25 rotated by a high-speed motor 24, a lens 26, and a folding mirror 27 performs image exposure on the photosensitive drum 21 to form an electrostatic latent image. In addition, in an electrophotographic copying machine, a scanning optical device is used to scan the photosensitive drum 21.
It differs from the above in that the top is exposed.

The electrostatic latent image on the photosensitive drum 21 is formed using colored charged particles (hereinafter referred to as developer) by a known developing means 28 such as a two-component developing method, a cascade developing method, a jumping developing method, or a touchdown method. Make it adhere. The transfer material 8 in the paper cassette 29 is fed by a pickup roller 31, and the timing roller 32 controls and transports the transfer material 8 so that the image on the photosensitive drum 21 and the position of the transfer material 8 coincide with each other. The toner image on the photosensitive drum 21 is transferred onto a transfer material 8 by a transfer corona charger 33, and this transfer material 8 is conveyed by a conveyor belt 35 that is conveyed by a conveyor belt drive roller 34, and is pressed against a fixing roller 7. Transfer material 8 is transferred by heat fixing device B combined with roller 6.
The paper is fixed on the top and discharged onto the paper discharge tray 36.

On the other hand, the toner remaining after transfer on the photosensitive drum 21 is removed by a cleaning device 37 composed of a rubber blade, a fur brush, etc., and an image is formed again. All of these functions except for the paper cassette 29 and the paper discharge tray 36 are accommodated within the main body frame A.

[0005] The main body frame A is a semi-closed type, and the paper ejecting section 39 for the transfer material 8 provided in line with the insertion opening of the paper cassette 29 and the exit of the heat fixing device B is open, and the other parts are also fully closed. is not made airtight.

[0006] An exhaust fan 41 is provided to exhaust gas after cleaning heat generated by the heat fixing device B and ozone generated by the corona charger 22, transfer charger 33, and the like.

Conventionally, the above-mentioned fixing devices in image forming apparatuses such as general printers and electrophotographic copying machines include:
Although various fixing devices have been devised and put into practice, heat fixing devices are currently the mainstream. There are heat fixing devices that allow the image support material to pass through the furnace without contacting the heat source, but among them, heat roller fixing devices that use a pair of rollers are often used due to their high thermal efficiency. . The basic configuration is shown in FIG. 4, taking as an example a case where a roller having a heat source is used on the image forming side. The fixing roller 7 has a heat source 4 such as a halogen heater inside. A pressure roller 6 whose surface layer is made of an elastic material 5 such as rubber and which is pressed by a pressure means (not shown) toward the fixing roller 7 and a fixing roller 7 are paired with an appropriate nip. ,
The image forming apparatus is rotated in the direction of the arrow shown in the figure by a driving means (not shown) driven by the main body of the image forming apparatus. During operation, fixing roller 7
The surface of is maintained at a substantially constant temperature by a thermistor (not shown) or the like. The transfer material 8, which is an image support material that supports the unfixed image formed by the developer 9 in the latent image forming section, is exposed to the heat generation source 4 when being conveyed while being sandwiched between the fixing roller 7 and the pressure roller 6.
The image is fixed on the transfer material 8 by the heat and the pressure between the rollers 6 and 7. The fixing roller 7 is constructed with a coating resin layer 1 as the uppermost layer on a core metal 3 with a primer layer 2 as an adhesive interposed therebetween to prevent adhesion of developer. Silicone rubber, fluororesin film or tube is used for such a resin layer. Examples of preferably used fluororesin materials include perfluoroalkoxide (PFA).
, polytetrafluoroethylene (PTFE), hexafluoropropylene and copolymer (FEP), and the like. Usually, a release agent application means is provided, but in that case, a web supply roller 15 wound with a cleaning web 10 impregnated with a release agent such as silicone oil, and a cleaning web fed from the web supply roller 15 are provided. 10, and a web pressure roller 11 that presses the cleaning web 10 toward the fixing roller 7. As a result, a release agent is applied to the fixing roller 7, and the developer attached to the fixing roller 7 is removed. Note that the so-called cleaning-less fixing device does not include a release agent application means, and prevents developer from adhering only by the release property of the surface layer of the fixing roller 7.

The release agent application means impregnates the application member with the release agent so that it can come into contact with the fixing roller 7. As the release agent application means, for example, a cleaning member impregnated with the release agent is used. There are webs, felt pads, felt rollers, etc., pore flons with a permeable membrane on the bottom of the release agent container from an oil pan, coating rollers, etc. to apply the coating. Another method is to apply a release agent to the elastic body of the pressure roller. Oil such as silicone is used as a mold release agent. In the heat fixing device B, a large amount of heat is emitted from the heat generating source 4, which heats the image input device, the photosensitive drum, and the surrounding members around the fixing device B, thereby preventing deformation of the optical members and fusion of the developer. Therefore, a heat insulating cover 12 is provided.

[0009]

The volatile components are mainly contained in the binder resin constituting the developer. Synthetic polymers are generally used as the binder resin, but during polymer synthesis, monomers, oxides of monomers, impurities in monomers, solvents, etc. are incorporated into the polymer. These components are removed as much as possible during polymer synthesis, but even in trace amounts, these components can be perceived as an odor.

[0010] In an image forming apparatus, a heat fixing device consumes most of the electric power for heating. For example, when the maximum power of the image forming device is 100V15A, the heat fixing device is 9
In addition, a heating fixing device in which two halogen heaters are housed in the heating roller consumes a larger amount of power at startup. However, the temperature of the fixing roller 7 is 170°C to 18°C.
Since the temperature is controlled at 0° C., the heat fixing device B and its vicinity are at a high temperature.

During heat fixing, volatile components contained in the developer evaporate. If this amount of volatilization is large, an unpleasant odor will be produced during fixing. Furthermore, depending on the usage conditions of small printers used on desktops, the odor may be bothersome even if the amount is small. High-speed machines fix a large number of sheets per unit time, so if you copy or print a large number of images with a large image ratio at once, you may notice an odor.

Further, in the step of charging the photosensitive drum 21 of the latent image carrier during formation of a latent image, a corona charger using a corotron, scorotron, or the like is generally used as the primary charger. When the corona charger becomes dirty, spark discharge, abnormal discharge, leakage, uneven discharge, etc. occur, and the photosensitive drum 21 is non-uniformly charged and the latent image is disturbed. As a result, image quality deterioration such as density unevenness, black streaks, white streaks, black spots, and white spots occurs. In particular, halftone solid images are prone to image deterioration, and uneven density and vertical streaks are likely to appear.

On the other hand, if the release agent applying means is exposed to high temperature for a long time on the fixing roller 7 of the fixing means, some volatile components of the release agent will be generated. When these volatile components diffuse into the image forming apparatus, they are attracted by the corona discharge and adhere to the wires of the corona charger, causing the charger to become dirty. Then, corona discharge is disturbed, resulting in deterioration of image quality. Similarly, if the volatile components of the release agent adhere to the photosensitive drum, there is a risk of deterioration in image quality.

The first object of the present invention is to provide a fixing device for an image forming apparatus that prevents the volatile components of the developer from dispersing outside the machine during fixing and prevents the generation of unpleasant odors. be.

The present invention prevents the volatile components of the release agent in the fixing device from diffusing into the machine, prevents the corona charger from becoming dirty, stabilizes corona discharge, and provides an image forming apparatus that does not cause image quality deterioration. Another object of the present invention is to provide a fixing device.

[0016]

[Means for Solving the Problems and Effects] The present invention provides a developing method by arranging a member carrying an adsorbent in the fixing device, for example, near the heating fixing means or the release agent applying means, or near the fixing device. It is possible to adsorb volatile components generated during fixing of the agent, prevent them from diffusing inside and outside the image forming apparatus, and prevent unpleasant odors from occurring. In addition, by adsorbing the volatile components of the release agent and preventing it from diffusing into the image forming apparatus and preventing the corona charger from becoming dirty, the charge on the latent image carrier is made uniform and the disturbance of the latent image is prevented. This made it possible to prevent this. As a result, stable and good images can be continuously obtained.

[0017] In each aspect of the present invention, an adsorbent is an agent that can physically or chemically capture a substance in a gas phase at its interface. For example, silica gel, alumina, titania, activated carbon, activated carbon fiber, porous glass, porous alumina, zirconia, magnesia, porous metal oxides, porous ceramics, zeolite, karyon, montmorillonite, vermiculite, etc. There are clay minerals, etc. These may be used alone or in combination. The adsorbent is preferably in a form that allows a large surface area, and the adsorbent carrier is also preferably in a form that allows the surface area for supporting the adsorbent to be as large as possible.

The first aspect of the present invention has an image forming section that outputs an unfixed image on an image supporting material, and the unfixed image formed on the image supporting material is passed through the image supporting material. , an image forming apparatus equipped with a fixing device configured to have means for heat fixing, characterized in that the fixing device or a member supporting an adsorbent is provided in the vicinity of the fixing device.

The second aspect of the present invention has an image forming section that outputs an unfixed image on an image supporting material, and the unfixed image formed on the image supporting material is conveyed by nipping the image supporting material. of,
comprising a means for heating and fixing the image by contacting the image support material, and
In an image forming apparatus configured to include a release agent applying means for applying a release agent to the heat fixing means, the image forming apparatus may include a fixing device or a member supporting an adsorbent in the vicinity of the fixing device. This is an image forming apparatus with features.

[0020]

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to some drawings.

[0021]

[Example 1] Electrophotocopy machine [Product model NP-8580]
(manufactured by Canon Inc.)] was modified and equipped with a fixing device related to the present invention, and a copying test was conducted and an odor test was conducted. The electrophotographic copying machine inputs an image using a scanning optical device, the photosensitive layer of the photosensitive drum 21 is made of amorphous silicon, and the heat fixing device B is a heat roller fixing device. The outline of the image forming apparatus is the same as that shown in FIG. 3 except for the image input section. Further, as shown in FIG. 1, an adsorbent carrying member 13 coated with activated carbon as an adsorbent was installed inside the heat insulating cover 12 of the fixing device. The developer was synthesized by a suspension polymerization method and kneaded together 100 parts by weight of a styrene-acrylic resin without residual component removal treatment, 80 parts by weight of magnetic iron oxide, 2 parts by weight of a negative charge control agent, and 3 parts by weight of low molecular weight polypropylene. A fine powder having a weight average particle size of 8.5 μm was obtained by pulverization and classification, and 0.6 parts by weight of hydrophobic colloidal silica was externally added thereto.

[0022] Continuous copying was performed and a panel test was conducted by seven people. Four people answered that it smelled a little, and three people said that it smelled but it didn't bother them.

[0023] Next, the adsorbent supporting member 13 was removed and a similar test was conducted. 5 people answered that it smells unpleasant.
Two people said they could smell it, but it was not unpleasant.

Furthermore, styrene treated to remove residual components
Using a developer using acrylic resin, the adsorbent supporting member 1
3 was installed and a similar test was conducted. As a result, 2 people said they didn't smell it, 4 people said it smelled slightly, and 1 person said it smelled, but they wouldn't notice it unless they were careful. here,
When a test was conducted by attaching an adsorbent supporting member to the paper discharge section 39, 5 people answered that there was no odor, and 2 people answered that there was a slight odor.

In this way, the paper discharge section 3 near the fixing device B
It was confirmed that the effect was further improved by attaching it to 9. Analysis of the odor components by gas chromatography revealed that they were residual monomers and their oxidized components.

[0026]

[Other Examples]

[0027]

[Embodiment 2] The fixing device of a printer [product type LBP-8-2 (manufactured by Canon Inc.)] was modified to the fixing device related to the present invention. This fixing device was attached to the printer described above, and a print test was conducted to conduct an odor test. Further, as shown in FIG. 1, an adsorbent carrying member 13 coated with activated carbon as an adsorbent was installed inside the heat insulating cover 12 of the fixing device B or inside the printer body near the heat fixing device B. The developer was composed of 100 parts by weight of styrene acrylic resin synthesized by suspension polymerization and treated to remove residual components, and 8 parts by weight of magnetic iron oxide.
0 parts by weight, 2 parts by weight of a negative charge control agent, and 3 parts by weight of low molecular weight polypropylene were kneaded, pulverized, and classified to obtain a weight average particle size of 8.
A fine powder of 5 μm was obtained and 0.6 parts by weight of hydrophobic colloidal silica was added externally.

[0028] As a result of continuous printing and a panel test conducted by 7 people, 4 people said that they noticed the smell, but it was not unpleasant at all, and 3 people said that they would not notice the smell unless they were careful. I said no.

[0029] When all of the adsorbent supporting members 13 were removed and a similar test was conducted, seven people answered that the odor was not unpleasant, but it was odor. On the other hand, when a similar test was conducted with the adsorbent carrying member 13 further installed near the paper ejection section 39 and paper ejection fan 41 near the fixing device B, 7 people answered that the odor was not bothersome, and the effect was even more effective. has risen.

[0030]

Example 3 A continuous copying test was conducted in the same manner as in Example 1, except that the adsorbent was a mixture of activated alumina and silica gel. As a result, the odor during copying was significantly reduced by attaching the adsorbent supporting member 13.

[0031]

[Example 4] Example 2 except that the adsorbent was made of porous glass
A print test was conducted in the same manner as above. As a result, the odor during printing was reduced.

[0032]

[Embodiment 5] The image forming apparatus is the same as in Embodiment 1,
Since the outline of the fixing device is generally the same as that shown in FIG. 2, it will be explained with reference to FIG. The coating resin layer 1 of the fixing roller 7 was a PFA coat, and the release agent with which the cleaning web 10 was impregnated was dimethyl silicone oil. Further, as an adsorbent, an adsorbent holding member 13 coated with silica gel was installed inside the heat insulating cover 12 of the fixing device.

The developer is styrene-acrylic resin 100
Parts by weight, 80 parts by weight of magnetic iron oxide, 2 parts by weight of a negative charge control agent, and 3 parts by weight of low molecular weight polypropylene were kneaded, pulverized, and classified to obtain a fine powder with a weight average particle size of 8.5 μm, and hydrophobic colloidal silica was obtained. 0.6 part by weight was added externally.

When a copying test of 100,000 sheets was conducted without cleaning the wires of the corona chargers 22 and 33, no defects appeared in the images. Also, a halftone solid image was produced every 10,000 sheets to check for density unevenness and vertical streaks. After the 30,000th sheet, slight unevenness in vertical stripe density began to be seen, but it did not suddenly worsen. At the time of printing 100,000 sheets, there was some density unevenness, but when wire cleaning was performed at this point, the density unevenness disappeared.

On the other hand, after removing the adsorbent supporting member 13,
When a similar copying test was conducted, density unevenness began to occur in halftones after 20,000 copies, and gradually worsened. Then, when 80,000 copies were printed, black spots occurred due to abnormal discharge, so the process was discontinued. Here, even if wire cleaning was performed, the black spots did not disappear, and the density unevenness did not disappear, although the degree became lighter.

[0036]

Example 6 A 100,000-sheet copying test was conducted in the same manner as in Example 5, except that activated alumina was used as the adsorbent. There were no black spots, and the slight density unevenness at 100,000 sheets almost disappeared by cleaning the wire.

[0037]

Example 7 A 100,000 copy test was conducted in the same manner as in Example 5 except that the adsorbent was a mixture of activated carbon and titania. The light vertical streaks on the halftone that were present at 100,000 copies are
By cleaning the wires of the corona chargers 22 and 33, they became much lighter and no longer noticeable.

[0038]

Example 8 A 100,000 copy test was conducted in the same manner as in Example 5 except that the adsorbent supporting member 13 was made of porous glass. As a result, no black spots occurred, and density unevenness on halftones did not worsen, and when the wires of the corona dischargers 22 and 33 were cleaned, the density unevenness almost disappeared.

[0039]

[Example 9] In Example 5, a copying test was conducted by operating the automatic wire cleaning machine installed in the corona charger 22, and no density unevenness occurred.

It should be noted that the present invention is not limited to the fixing device described above, but can be applied to any heat fixing method. For example, the heat fixing method shown in FIG. 5 can also be applied.

That is, in FIG. 5, an endless belt 45 of a release resin layer is applied to the drive means 42, rotatable rollers 43, and heat generation source 4, and pressure is applied to the heat generation source 4 by a pressure roller 6 to form an undetermined shape. The transfer material 8 supporting the developer 9 is fixed by passing the pressure roller 6 between the belts 45 of the release resin layer and applying heat and pressure by the heat generating source 4.

[0042] As described above, the activated carbon of the adsorbent used in each example,
Activated carbon alumina, silica gel, porous glass are developers,
The effect of adsorbing the volatile matter of the mold release agent has been recognized, and even if an adsorbent support member is provided for the purpose of adsorbing the volatile matter of the developer, and an adsorption support member is provided for the purpose of adsorbing the mold release agent, both have a mutually effective effect. It's what it does.

[0043]

Effects of the Invention As explained above, by providing an adsorbent carrying member in the fixing device or in the vicinity of the fixing device, volatile matters from the developer can be adsorbed and diffused into and out of the image forming apparatus, and unpleasant It is now possible to prevent odors.

[0044] It should be noted that the deodorizing effect can be further enhanced by installing an adsorbent carrier near the fixing device, such as the paper discharge section or the exhaust fan.

[0045] Furthermore, by providing an adsorbent supporting member in or near the fixing device, when a releasing agent application means is provided, the volatile matter of the releasing agent is adsorbed and diffused into the image forming apparatus. This makes it possible to prevent contamination of corona chargers, etc.

[0046] This stabilizes the corona discharge, allows the latent image carrier to be charged uniformly, reduces density unevenness and vertical streaks, and prevents the occurrence of black spots and the like.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of a fixing device according to the present invention.

FIG. 2 is a longitudinal sectional view of another embodiment of the fixing device according to the present invention.

FIG. 3 is a longitudinal sectional view of an embodiment of the image forming apparatus of the present invention.

FIG. 4 is a vertical cross-sectional view of a conventional example.

FIG. 5 is a longitudinal sectional view of another embodiment of a fixing device to which the present invention is applied.

[Explanation of symbols]

1 Coating resin layer 2 Primer layer 3 Core metal 4 Heat source 5 Elastic body 6 Pressure roller 7 Fixing roller 8 Transfer material 9. Developer 10 Cleaning web 11 Web pressure roller 12 Insulation cover 13 Adsorbent supporting member 39 Paper discharge section 41 Exhaust fan

Claims (2)

[Claims] [Claim 1] An image forming section that outputs an unfixed image on an image support material, and a means for passing the image support material and heating and fixing the unfixed image formed on the image support material. An image forming apparatus equipped with a fixing device configured as above, characterized in that the image forming apparatus has a member that carries an adsorbent in the fixing device or in the vicinity of the fixing device. 2. An image forming section that outputs an unfixed image on an image supporting material, the image supporting material being conveyed in a pinched manner, and the unfixed image formed on the image supporting material being brought into contact with the image supporting material. In the image forming apparatus, the fixing device or the vicinity of the fixing device is provided with a releasing agent coating device for applying a releasing agent to the heating fixing device. An image forming apparatus comprising: a member that supports an adsorbent;