JP4185107B2 - How to recycle and collect toner carrier - Google Patents

Description

  The present invention relates to a method for regenerating and recovering toner carrier out of developers used in image forming apparatuses based on electrostatic recording or electrophotography, that is, regenerating the carrier particles comprising magnetic metal powder particles. It relates to the method of recovery.

  In general, the carrier, which is one of the particles constituting the two-component developer, is formed of a magnetic metal such as iron, nickel or cobalt, or a magnetic metal oxide such as ferrite or magnetite. An organic coating layer of about 0.1 to 10 microns made of acrylic resin, silicone resin, fluororesin or the like is provided on the surface, and a spherical shape is used.

  In the developing method using a two-component developer, the toner is consumed in the developing unit of the image forming apparatus and is always replaced with new toner, whereas the carrier is returned from the developing unit to the carrier accommodating unit and is transferred into the image forming apparatus. It is used repeatedly. Therefore, the chargeability gradually deteriorates as the toner adheres to the resin coating layer on the carrier surface, the resin film layer wears, or peels off during repeated use. Since it is unavoidable that the image quality fluctuates, it is difficult to obtain the initial image quality, so that it is necessary to replace the carrier in a timely manner.

  Carriers that have been used and replaced as described above have been discarded as industrial waste or used as raw materials for iron or steel making. However, in recent years, emissions of carbon dioxide, effective use of resources, and other global environments As destruction has become a social issue, it has become necessary to reduce industrial waste.

Under such circumstances, it is very beneficial not only for the environmental impact but also for the product cost to recycle and recover the used carrier for use. . Therefore, technical development for collecting used carriers or carriers discarded such as defective products in the manufacturing process and regenerating them so that they can be used again as a carrier, for example, Japanese Patent Laid-Open No. 63-212945, Kaihei 7-72665 etc. are performed.
JP-A 63-212945 JP 7-72665 A

  However, up to the present, including the above-mentioned Patent Documents 1 and 2, no technology has been developed to recover the silicone resin-coated carrier so that it can be reused.

  The present invention is intended to solve the above-mentioned problems, and the object of the present invention is to avoid the loss of the shape and particle size of the magnetic particles, and the magnetic particles of the carrier without changing the structure and magnetic properties of the magnetic particles. An object of the present invention is to provide a toner carrier regeneration and recovery method capable of efficiently removing only the silicone resin coating layer having a deteriorated surface at low cost.

In order to achieve the above-mentioned object, the present invention provides a silicone resin film carrier out of used toner carrier particles or defective toner carrier particles produced in the manufacturing process under a temperature condition that allows carbonization in an oxygen-free or anoxic state. A carbonization treatment step of heating and carbonizing the resin coating layer on the surface; a decarburization step of heating and decarburizing the carbide by heating under a temperature condition that is slightly higher than the carbonization treatment step; And a residual film removing step of removing the silica and silica compound film remaining on the carrier particles later, and the silicone resin-coated carrier can be regenerated.

  The invention according to claim 2 is characterized in that the heating temperature of the carbonization treatment step is 300 to 700 ° C., and the carbonization treatment can be performed efficiently.

  Furthermore, the invention described in claim 3 is characterized in that the heating temperature in the decarburizing step is 300 to 800 ° C., and is configured to perform the decarburizing treatment efficiently.

  Furthermore, the invention according to claim 4 and claim 7 is characterized in that in the residual film removing step, silica or silica compound as a residual film is reacted with an aqueous hydrogen fluoride solution or fluorine gas. It was constructed so as to be effectively removed as silica tetrafluoride or silicohydrofluoric acid.

  Furthermore, the invention according to claim 5 is characterized in that the concentration of the hydrogen fluoride aqueous solution is 1 to 50%, and is configured to improve the reactivity with silica and the silica compound.

  Furthermore, the invention described in claim 6 is characterized in that the hydrogen fluoride aqueous solution is one to which hydrogen peroxide is added, and can further promote the reaction with silica and silica compound. .

  According to the present invention, the deteriorated silicone resin film layer on the surface of magnetic particles of the collected used toner carrier or defective toner carrier produced in the manufacturing process is carbonized, decarburized, treated with hydrogen fluoride, and coated with silicone. The covering film can be completely peeled off. If the magnetic particles after separation and removal are separated, washed with water, and dried, the magnetic particles are regenerated to a state close to the original magnetic metal particles, that is, regenerated to a usable toner carrier by correcting the magnetic characteristics and electrical characteristics. It has an excellent effect that it becomes possible.

  In other words, the present invention is a heat treatment at a lower temperature than the conventional method, so that the shape and particle size of the magnetic particles are not changed, and the structure and magnetic properties of the magnetic particles are not significantly changed. Thus, an excellent effect is achieved that the initial charging characteristics can be efficiently regenerated with a small amount of energy.

  In addition, according to the invention of claim 2, since the heating temperature in the carbonization treatment step is 300 to 700 ° C., an excellent effect that the carbonization treatment can be performed efficiently is achieved.

  Furthermore, according to invention of Claim 3, since the heating temperature of the said decarburization process is 300-800 degreeC, it has the outstanding effect that a decarburization process can be performed efficiently. .

  Furthermore, according to the invention of claim 4 and claim 7, the residual film removal step is characterized by reacting silica or a silica compound, which is a film remaining after decarburization, with an aqueous hydrogen fluoride solution or fluorine gas. Therefore, this reaction exhibits an excellent effect that it can be effectively removed as silica tetrafluoride or silicohydrofluoric acid.

  Furthermore, according to the invention of claim 5, since the concentration of the aqueous hydrogen fluoride solution is 1 to 50%, the excellent effect of further improving the reactivity with silica and silica compound is obtained. It is what you play.

  Furthermore, according to the invention of claim 6, since the hydrogen fluoride aqueous solution is characterized in that hydrogen peroxide is added, the reaction with silica and silica compound can be further promoted. It is effective.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view of a magnetic particle regeneration treatment process, and FIG. 2 is a flowchart showing each apparatus and flow for carrying out the method of the present application.

  In the present application method, as shown in FIG. 1, a carbonization treatment step 2 for carbonizing the surface of a used toner carrier particle or a defective toner carrier particle (hereinafter also referred to as magnetic particle) 1 produced in the manufacturing process 1 is carbonized. The regenerated magnetic particles 1 ′ are obtained through a decarburizing step 3 for burning and removing the carbides and a residual coating removing step 4 for peeling off and removing the coating remaining on the surface of the magnetic particles 1 after decarburization.

  In the carbonization treatment step 2, the primary treatment product 1 a is obtained by heating the resin coating layer on the surface by heating under a temperature capable of carbonization (eg, 300 to 700 ° C.) in an oxygen-free or anoxic state. It is a process of generating.

  In the decarburization step 3, the carbonized carbide (primary treatment product) 1 a is burned and removed by heat treatment (300 to 800 ° C. slightly higher than the carbonization treatment step) in an atmosphere containing minimum combustion necessary oxygen. It becomes a process. That is, the primary treated product 1a is removed as carbon monoxide or carbon dioxide, and therefore the magnetic particle 1 does not impair its shape and magnetic properties.

  In the residual coating removal step 4, silica and a silica compound remain as a coating (secondary treatment 1b) on the surface of the heat-treated magnetic particles 1. After the heat treatment in the decarburization step 3, the secondary treatment product 1b is cooled and reacted with a hydrogen fluoride aqueous solution or a fluorine gas at a temperature of 60 ° C. or less to peel off as tetrafluorosilica and hydrosilicofluoric acid. It is a process of removing. The concentration of the aqueous hydrogen fluoride solution at this time is preferably in the range of 1 to 50%. The amount of fluorine used in the aqueous solution of hydrogen fluoride is equal to or greater than the amount of silicon contained in the silicone resin coating layer to be treated.

  The gas of silica tetrafluoride generated through the residual film removal step 4 is taken out of the system, silicohydrofluoric acid remains in the reaction system, hydrofluoric acid is separated in the separation step 5, and the drying step 6 After that, it is recovered as regenerated magnetic particles 1 '.

  The concentration of the aqueous hydrogen fluoride solution at this time is preferably in the range of 1 to 50%. The amount of fluorine used in the aqueous solution of hydrogen fluoride is equal to or more than the amount of silicon contained in the silicone resin coating layer to be treated.

  FIG. 2 shows an apparatus for carrying out the method of the present application. In the heating carbonization processing apparatus 10 that realizes the carbonization processing step 2, as shown in the figure, the recovered magnetic particles 1 are fed from the hopper 11 through the screw feeder 12 into the upper heating cylinder 13 of the heating furnace, 300-700 ° C (preferably 450-600 ° C), which is a carbonization condition under anoxic and poor oxygen conditions while being transferred forward (in the direction of arrow B) by the screw conveyor 13a in the heated cylindrical body 13. Primary heating at a temperature of

  The resin coating layer is heated, decomposed and gasified in a low temperature region, and the carbonized carbon is partially attached to the carrier particle 1 and partly peeled off from the particle surface. , Produced in carbides. At that time, the gas generated in the heated cylindrical body 13 by heating and decomposition of the resin coating layer is sucked through the duct 14 and the ejector 15, mixed with the combustion air, and sent to the hot air generating furnace 16. It is burned and decomposed in the furnace 16, passed through the heating furnace 17, and exhausted through the exhaust tower 18. Since the exhaust is burned / decomposed, it does not harm the surrounding environment.

  Thus, after the resin coating layer on the surface is heated and carbonized, the magnetic particles 1 are supplied through the double damper 19 into the lower heating decarburization cylinder 20 and the heating decarburization cylinder. While being transferred forward (in the direction of arrow B) by the screw conveyor 20a in the body 20, air is supplied from the air supply port 21 at a temperature of 300 to 800 ° C (preferably 500 to 650 ° C) slightly higher than the primary heating. Decarburized by heating and combustion in an atmosphere containing the minimum amount of oxygen required for combustion

  Next, the magnetic particles 1 that have been decarburized are further discharged through the double damper 22, the cooling conveyor 23, and the discharge port 24 into the storage bowl 25. Since a film of silicon, silicon compound or the like remains on the surface of the magnetic particles 1 subjected to decarburization treatment, the film is transferred (two-dot chain line) 27 from the container 25 to the reaction tank 26 and the reaction is performed. A stirrer 28 that rotates in the tank 26 is reacted with a 1-50% hydrogen fluoride aqueous solution 29 at room temperature for 30-60 minutes.

  As a result of the above reaction, silica and silica compounds, which are residual films, are peeled and removed as silica tetrafluoride gas and silica fluorosilicate. Thereafter, it is separated by the solid-liquid separator 30 (separation step 5), and the solid content (magnetic particles) K is transferred to the drying device 32 through the water washing device 31, and forward (in the direction of arrow C) by the screw conveyor 32a. It is dried (drying step 6) while being transferred. The dried magnetic particles remain spherical and are regenerated 26 as magnetic particles that are not significantly different from the initial toner carrier.

  Silica tetrafluoride, which is a reaction product of the reaction tank 26, is transferred 33 from the upper part of the reaction tank 26, and filled with a calcium compound such as calcium hydroxide or calcium oxide through a gas treatment tower 34 equipped with a water spray. Release 35 into.

  The liquid (silica fluorosilicate) W separated by the solid-liquid separator 30 and the cleaning liquid 36 from the gas treatment tower 34 are contained in a wastewater treatment device 37 filled with a calcium compound such as water oxygenated calcium or calcium oxide. Supplied and processed. The fluorine contained after the treatment is fixed harmlessly as calcium fluoride, and the waste water is discharged 38.

  In the upper heating cylinder 13 and the heating decarburization cylinder 20, screw conveyors 13a and 20a are rotatably provided, respectively, but the present invention is not limited to this, and is like a rotary kiln. It is also possible to have a structure that can be rotated.

  Moreover, although the said upper heating cylinder 13 and the heating decarburization cylinder 20 are comprised in the up-and-down relationship as a heating furnace, this invention is not limited to such a thing, The apparatus for carbonization process steps It is also possible to separately provide equipment for the decarburization process.

  The present invention collects a toner carrier in a developer used in an image forming apparatus using an electrostatic recording method or an electrophotographic method, and can reuse deteriorated carrier particles or defective products produced in the manufacturing process. By recycling the wastewater, it is not discarded as industrial waste, enabling effective use of resources, and reducing the amount of industrial waste discharged.

It is explanatory drawing of the reproduction | regeneration processing process of a magnetic particle. It is a flowchart which shows each apparatus and flow for enforcing this application method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic particle 1 'Regenerated magnetic particle 2 Carbonization process 3 Decarburization process 4 Residual film removal process 1a Primary treatment 1b Secondary treatment 5 Separation process 6 Drying process 10 Heating carbonization apparatus 11 Hopper 12 Screw feeder 13 Upper heating cylinder Body 13a Screw conveyor 14 Duct 15 Ejector 16 Hot air generator 17 Heating furnace 18 Exhaust tower 19 Double damper 20 Heating decarburization cylindrical body 20a Screw conveyor 21 Air supply port 22 Double damper 23 Cooling conveyor 24 Discharge port 25 Storage rod 26 Reaction Tank 27 Transfer 28 Stirrer 29 Hydrogen fluoride aqueous solution 30 Solid-liquid separator 31 Water washing device 32 Drying device 32a Screw conveyor 33 Transfer 34 Gas treatment tower 35 Release 36 Cleaning solution 37 Waste water treatment device 38 Discharge

Claims (7)

Of the used toner carrier particles or defective toner carrier particles produced in the manufacturing process , the silicone resin film carrier is heated under a temperature condition capable of carbonization in an oxygen-free or anoxic state to carbonize the resin coating layer on the surface. A carbonization process, a decarburization process in which the carbide is burned and decarburized by heating at a temperature that is slightly higher than that of the carbonization process, and silica and silica compounds remaining in the carrier particles after decarburization . And a residual film removing step for removing the film of the toner carrier.   The toner carrier regeneration and recovery method according to claim 1, wherein a heating temperature in the carbonization treatment step is 300 to 700 ° C.   2. The toner carrier regeneration and recovery method according to claim 1, wherein a heating temperature in the decarburizing step is 300 to 800 ° C.   The method for regenerating and recovering a toner carrier according to claim 1, wherein the residual film removal step comprises reacting silica or a silica compound as a residual film with an aqueous hydrogen fluoride solution.   The toner carrier regeneration and recovery method according to claim 4, wherein the concentration of the hydrogen fluoride aqueous solution is 1 to 50%.   6. The toner carrier regeneration and recovery method according to claim 4, wherein the aqueous hydrogen fluoride solution is a solution to which hydrogen peroxide is added.   2. The toner carrier regeneration and recovery method according to claim 1, wherein the residual film removal step comprises reacting silica or a silica compound as the residual film with fluorine gas.

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