JP5343648B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, and a laser printer.

  Conventionally, various techniques have been proposed for heating and fixing a thermoplastic resin such as toner used in electrophotography to a recording medium. Among them, the technique that is most easily applied to a recording medium is used. In this case, a heated roller containing a heater lamp called a heat roll or a heated belt is directly brought into contact with paper as a recording material and heated to melt the thermoplastic resin. It is a method of fixing. Since the molten resin has adhesiveness, the surface of the heat supply roller or belt is used to weaken the adhesive force, that is, in order to provide releasability, a fluorine-based or silicon-based resin. Often used as a coating or lining.

  However, when the recording medium such as paper is insufficiently peeled off, a countermeasure is taken such as forming a thin film of a release agent on the surface of the heating member to improve the peeling of the recording member. As a supply source of the release agent, a method in which a member containing a release agent is applied in contact with a heating member or when the recording material itself contains wax and the recording material (toner) is melted by the heat of the heating member. A method of melting together to develop peelability is known. Various release agents and waxes have also been proposed. For example, silicone oil is a representative release agent, but various molecular weight distributions, cross-linking, side chain group modification, etc. are also used in silicone oil. It has been.

  In addition, various types of waxes such as low molecular weight polypropylene to natural carnauba wax are used. In general, a device that transports a recording medium at a high speed, and when a recording member such as color toner such as color printing is overlaid tends to be more difficult to peel off. A higher speed device directly heats with a heating member. In the apparatus that employs the fixing mechanism, the release agent tends to be applied to the heating member. In this case, it is desirable to apply the release agent in a predetermined amount with no change over time or in the position of the heating member.

  For example, Patent Document 1 proposes a coating that uniformly applies while using a capillary phenomenon. Further, as disclosed in Patent Document 2, an elastic body blade is provided, and a roller surface cleaning property and a mechanism for collecting the scraped oil are provided. On the other hand, there is an idea that the release agent only needs to be quantitatively supplied to a predetermined place. For example, in Patent Document 3, a release agent is sprayed on the surface of a heat roll by a piezo-type ink jet or the like according to an image or a paper type. A method of attaching is proposed. This method is a method of supplying a release agent only to a necessary portion, and is excellent from the viewpoint of resources. As a similar proposal, there is Patent Document 4 and the like, and a proposal is made such that the generated charged mist is selectively ejected to a roller by a circular electrode. The idea of attaching a partially misted release agent is even older, and for example, a method of misting with a piezo or a vaporizer has been proposed, as in the examples of Patent Document 5 and Patent Document 6.

  Silicone oil, which is commonly used as a release agent applied to the surface of a fixing roller, etc., is a colorless and transparent liquid. It is quantitatively measured by using a wavelength near the absorption peak using IR or the like in a normal analysis technique. Detection is performed.

  However, when the heater lamp is contained in the heat supply member, or when the absorption peak at IR is used because the temperature of the heat supply member itself is high, the detection sensitivity cannot be obtained. If the heat supply member is a fluorine-based compound, it is possible to separate the release agent due to a difference in absorption peak. However, when the heating member is made of a silicon-based resin, the release agent and the heating member It is impossible to separate the quantities. Therefore, it has been found that a separation method using infrared rays such as IR is difficult.

  Further, in order to use the principle of film thickness measurement used in the oil film method or the like, a method of adding a fluorescent agent or the like to the release agent is also conceivable. However, since the release agent is consumed together with the recording member, the choice of materials is reduced. What is used as an additive needs to be easily disperse | distributed with the silicone oil etc. which are base materials. Acetone, which is commonly used, is a problem, but there is a problem when used at high temperatures, and since it is a volatile substance, there is a concern of vaporization and effects on the human body. In addition, there is an example in which Coumarin or the like is mixed with oil for the film thickness of a cylinder in an automobile engine, but there is skin irritation and the like, which is not appropriate. Regarding the fluorescence phenomenon, since silicon oil is an optically relatively transparent substance, it is more advantageous to use deep ultraviolet rays with low transmittance, but it has high reactivity and is not suitable for long-time irradiation. Moreover, in order to ensure the SN ratio, a light source having a relatively high light intensity is required.

  The present invention has been made in view of the above, and in an apparatus for fixing a thermoplastic material such as toner to a recording medium by heat, by controlling the amount of the release agent applied, the release agent is excessively supplied. An object is to prevent image failure and failure due to recording medium peeling failure at the time of depletion.

  In order to solve the above-described problems and achieve the object, the present invention uses a recording material containing a thermoplastic resin, and fixes the image on a recording medium by heating and heat-fixes; and An image forming apparatus comprising: a coating unit configured to apply a release agent to a surface, wherein the fixing unit includes a fluorescent material at least on a surface layer, and detects the amount of the release agent on the surface of the fixing unit. Means are provided.

  The present invention relates to an apparatus for fixing a thermoplastic material such as toner to a recording medium by heat, and uses a means for quantitatively detecting the amount of the release agent on the surface of the fixing means based on a fluorescence phenomenon, and the amount of the release agent applied By controlling this, it is possible to prevent an image failure due to excessive supply of the release agent and a failure due to defective peeling of the recording medium at the time of depletion.

FIG. 1 is an explanatory diagram showing the configuration of the fixing device and its peripheral portion according to this embodiment. FIG. 2 is an explanatory diagram showing the configuration of an image forming apparatus equipped with the apparatus configuration of FIG.

  Exemplary embodiments of an image forming apparatus according to the present invention will be explained below in detail with reference to the accompanying drawings.

(Embodiment)
In an apparatus that fixes a thermoplastic material such as toner to a recording medium by heat as an image recording agent, the amount of release agent such as silicone oil used in an apparatus that heats by direct contact with a recording medium such as a heat roll is fluorescent. By using a means of quantitative detection based on the phenomenon and managing the coating amount of the release agent, image failure due to excessive supply of the release agent and failure due to defective release of the recording medium at the time of depletion are prevented. An object of the present invention is to provide a means for quantitatively measuring the amount of the release agent applied to the surface of the heating member. A specific configuration example will be described below.

  FIG. 1 is an explanatory diagram showing the configuration of the fixing device and its peripheral portion according to this embodiment. In FIG. 1, reference numeral 101 denotes a fixing roller as a heating member, reference numeral 102 denotes a release agent coating pad, reference numeral 103 denotes a release agent supply pump that supplies the release agent, and reference numeral 104 denotes a release agent storage tank that stores the release agent. Reference numeral 105 denotes a pressure roller that rotates by being urged by the fixing roller 101 with a predetermined pressure, reference numeral 106 denotes an ultraviolet light emitting laser that irradiates the surface of the fixing roller 101, and reference numeral 107 denotes detection that detects a release agent on the surface of the fixing roller 101. The reference numeral 108 is a shutter, the reference numeral 109 is a controller, the reference numeral 110 is a database, the reference numeral 111 is a recording medium such as paper, and the reference numeral 112 is a scraper for scraping off excess release agent on the fixing roller 101. A scraper drive solenoid for scraping off the release agent, reference numeral 113 is a release agent receiver, and reference numeral 114 is an inner part of the fixing roller 101. It is a heater for heating the fixing roller 101.

  Next, the operation centering on the fixing device shown in FIG. 1 will be described. When the recording material (toner) transferred onto the recording medium 111 passes between the fixing roller 101 and the pressure roller 105, heat is supplied to fix the recording material on the recording medium 111. The fixing roller 101 is heated by a heater 114 installed therein, and is controlled to be kept constant at a predetermined temperature by turning it on and off. As the material of the fixing roller 101, fluorine-based resin, silicone resin, or the like is used. In this example, it is assumed that silicon resin is used.

  In addition, this resin contains a fluorescent agent. There are various kinds of fluorescent agents such as solid and liquid, but a solid one is used for environmental stability. There are various materials such as titanium oxide, zinc oxide, and silicon-based oxides that emit fluorescence with ultraviolet rays. Here, zinc oxide, which is easily available, was used. The surface of the fixing roller 101 is irradiated with light from an ultraviolet light emitting laser 106 to generate fluorescence on the surface of the fixing roller 101. As the light source, there are light split by LEDs and slits, etc., but a small light source was selected in consideration of the signal detection sensitivity on the light receiving side in the apparatus. The fluorescence is captured by the detector 107 and converted into an electrical signal. A narrow band filter is installed in front of the detector 107 to reduce detection noise.

  Further, a laser emitting ultraviolet rays has high reactivity, and damage on the irradiation side can be considered, and since the laser diode itself has a short life, measurement is periodically performed at certain intervals. When the measurement is not performed, the solenoid of the shutter 108 is operated to protect the sensor.

  If there is a release agent on the surface of the fixing roller 101, light absorption occurs and the fluorescence intensity decreases. Therefore, the signal intensity obtained by the detector 107 is converted into a coating amount, and when the amount is smaller than the target amount, the supply amount of the release agent supply pump 103 is increased. When the information on the sheet (recording material) is known in advance, the recommended replenishment amount in the database 110 is first selected, and the replenisher replenishment amount is adjusted while performing feedback from comparison with the actual detection amount. When it is determined that the amount of application is extremely large, the printing operation is temporarily stopped, the release agent scraping scraper drive solenoid 112 is operated, and the operation of removing the excess release agent is performed. In a long-time use situation, the output intensity changes according to the use situation of the fixing roller 101. Therefore, the base line is adjusted based on the passing amount of the recording medium 111 so that an accurate application amount can be obtained. Correction is applied.

  When these mechanisms were mounted on our laser printer and actually printed, it was possible to obtain an image with a stable release agent coating amount on the fixing roller 101. Further, since the amount of circulating release agent was small, it was confirmed that the deterioration of the release agent and contamination due to recording material mixing were reduced.

  FIG. 2 shows a configuration of an image forming apparatus 200 equipped with the apparatus configuration of FIG. When a start key on an operation unit (not shown) is pressed on a document bundle placed on the document table 2 with the image surface facing up in the automatic document feeder (hereinafter referred to as ADF) 1, The lowermost document is fed to a predetermined position on the contact glass 6 by the feeding roller 3 and the feeding belt 4. It has a counting function for counting up the number of originals upon completion of feeding one original. After the fed original is read by the reading unit 50 on the image data of the original on the contact glass 6, the original that has been read is discharged by the feeding belt 4 and the discharge roller 5.

  The sheets as recording media stacked on the first tray 8, the second tray 9, and the third tray 10 are fed by the first sheet feeder 11, the second sheet feeder 12, and the third sheet feeder 13, respectively. Then, the sheet is conveyed to a position where it abuts on the photoreceptor 15 by the vertical conveyance unit 14. The image data read by the reading unit 50 is written on the photoconductor 15 by the laser from the writing unit 57 and passes through the developing unit 27 to form a toner image. The toner image on the photoconductor 15 is transferred while the paper is being conveyed by the conveyance belt 16 at the same speed as the rotation of the photoconductor 15. Thereafter, the image is fixed by the fixing unit 17 (having the configuration shown in FIG. 1), and is discharged to the subsequent apparatus by the paper discharge unit 18.

  The finisher 70 of the post-processing apparatus can usually guide the conveyed paper in the direction of the paper discharge roller 73 and the direction of the staple processing unit. By switching the switching plate 71 upward, the sheet can be discharged to the normal discharge tray 74 side via the transport roller 72. Further, by switching the switching plate 71 downward, the switching plate 71 can be conveyed to the staple table 78 via the conveying rollers 76 and 77.

  Each time a sheet of transfer paper loaded on the staple table 78 is discharged, the paper end surface is aligned by the paper aligning jogger 79, and is bound by the stapler 76 upon completion of partial copying. The transfer paper group bound by the stapler 76 is stored in the staple completion paper discharge tray 80 by its own weight. On the other hand, the normal paper discharge tray 74 is a paper discharge tray that can move back and forth.

  The paper discharge tray section 74 that can be moved back and forth moves back and forth for each original or each copy section sorted by the image memory, and sorts copy paper that is simply discharged.

  When forming an image on both sides of the paper, the paper fed from each of the paper feed trays 8 to 10 is transported to the double-sided paper feed path 93 without being guided to the paper discharge tray, and the reversing unit. At 92, the switchback is reversed and sent to the duplex conveying unit 91.

  The sheet sent to the duplex conveyance unit is sent again to the vertical conveyance unit 14 and is printed after an image is printed on the back side. When the paper is reversed and discharged, the paper switchback reversed by the reversing unit 92 is sent to the reverse paper discharge conveyance path 94 without being sent to the duplex unit and discharged.

  The photoreceptor 15, the transport belt 16, the fixing unit 17, the paper discharge unit 18, and the development unit 27 are driven by a main motor 25, and the paper feeding devices 11 to 13 drive the main motor 25 by paper feeding clutches 22 to 24, respectively. Driven by transmission. The vertical conveyance unit 14 is driven to transmit the drive of the main motor 25 by the intermediate clutch 21.

  The reading unit 50 includes a contact glass 6 on which an original is placed and an optical scanning system. The optical scanning system includes an exposure lamp 51, a first mirror 52, a lens 53, a CCD image sensor 54, and the like. Yes. The exposure lamp 51 and the first mirror 52 are fixed on a first carriage (not shown), and the second mirror 55 and the third mirror 56 are fixed on a first carriage (not shown). When reading a document image, the first carriage and the second carriage are mechanically scanned at a relative speed of 2: 1 so that the optical path length does not change. This optical scanning system is driven by a scanner drive motor (not shown). The document image is read by the CCD image sensor 54, converted into an electrical signal, and processed. The image magnification is changed by moving the lens 53 and the CCD image sensor 54 to the right. That is, the positions of the lens 53 and the CCD image sensor 54 are set in the left-right direction corresponding to the designated magnification.

  The writing unit 57 includes a laser output unit 58, an imaging lens 59, and a mirror 60. Inside the laser output unit 58, a rotating polygon mirror (polygon mirror) that rotates at a high speed at a high speed by a laser diode as a laser light source and a motor. ). Laser light emitted from the laser output unit 58 is polarized by a polygon mirror that rotates at a constant speed, passes through an imaging lens 59, is folded by a mirror 60, and is focused on the surface of the photoconductor 15 to form an image.

  The laser beam output from the writing unit 57 is applied to the image forming photoconductor 15. Although not shown, a beam sensor for generating a main scanning synchronization signal is disposed at a position where a laser beam near one end of the photoconductor 15 is irradiated.

  Therefore, according to the above-described embodiment, the fixing roller 101 in which the fluorescent agent is mixed can separate signals even when the same kind of material is mixed due to fluorescence. Further, since the fluorescent member uses ultraviolet rays, even a member using a heating element is hardly affected. Further, by using a fluorescence detector, it can be converted into an electric signal, and quantitative detection is possible. In addition, by using a light source that emits ultraviolet light, it is easy to obtain detection sensitivity by light absorption even for a relatively transparent material such as silicon. A shorter wavelength is particularly effective.

  Even when the same kind of substance is attached to the surface of the heating member, it can be separated from the degree of light absorption because no fluorescent agent is contained. In particular, in the case of a solid fluorescent agent, elution can be prevented and a stable signal can be obtained. In addition, the amount of material can be specified in order to utilize the property of absorbance by ultraviolet rays. Moreover, versatility is obtained by converting it as an actual physical quantity. In addition, by actually performing feedback control, it is possible to maintain a stable film thickness for a long period of time. In addition, in the case where the applied release agent is excessive, in the past, there was only a means for discharging together with the recording member, but by removing with a release agent scraping scraper, the consumption of the recording member was prevented. The application amount can be adjusted.

  As described above, the image forming apparatus according to the present invention is useful for an image forming apparatus such as a copying machine or a printer. In particular, the image forming apparatus is applied to a fixing device that applies a release agent to a fixing member or the like and an application device that applies a release agent. Is suitable.

DESCRIPTION OF SYMBOLS 101 Fixing roller 102 Release agent application pad 103 Release agent supply pump 104 Release agent storage tank 105 Pressure roller 106 Ultraviolet light emitting laser 107 Detector 108 Shutter 109 Controller 110 Database 111 Recording medium 112 Scraper drive solenoid 113 for release agent scraping Release agent 114 heater

Japanese Patent No. 3875232 Japanese Utility Model Publication No. 5-41996 US Pat. No. 5,708,914 JP 2000-235321 A JP-A-53-129051 JP 60-235177 A

Claims (8)

An image forming apparatus comprising: a fixing unit that uses a recording material containing a thermoplastic resin, heat-fixes the recording medium by heating, and a coating unit that applies a release agent to the surface of the fixing unit. And
The fixing unit contains a fluorescent material at least on the surface layer,
An image forming apparatus comprising: a release agent detecting means for detecting the amount of the release agent on the surface of the fixing means.   2. The image forming apparatus according to claim 1, wherein the fluorescent material contained in the fixing unit is an ultraviolet fluorescent material. The release agent detecting means is
A light irradiation means for irradiating the fixing means containing a fluorescent material with light;
The image forming apparatus according to claim 1 or 2 further comprising a a fluorescence detector for detecting fluorescence from the irradiated excitation caused the said fixing means by said light irradiating means.   The image forming apparatus according to claim 3, wherein a light source of the light irradiation unit is an ultraviolet ray. The release agent, an image forming apparatus according to claim 3 or 4, characterized in that it has a light absorbing property against the light from the light irradiation unit. The image forming apparatus according to claim 3 , wherein the amount of the release agent applied is converted from the fluorescence intensity obtained by the fluorescence detection unit . The image according to any one of claims 1 to 6, further comprising an application amount adjusting unit that holds the application amount of the release agent at a predetermined amount based on the application amount of the release agent. Forming equipment. When the release agent is excessively supplied, the image according to any one of claims 1 to 7, characterized in that it comprises an excessive release agent removing means for divided the fixing hands stage or al release agent Forming equipment.

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