JP5088248B2 - Intermediate transfer belt defect inspection method and defect inspection apparatus - Google Patents

Description

The present invention relates to a defect inspection method for an intermediate transfer belt and a defect for measuring a defect in the molecular structure of the intermediate transfer belt made of a dielectric sheet material including a granular material made of a conductive material formed by extrusion molding. It relates to an inspection device.

  Various parts included in image generation apparatuses such as printers and copiers use conductive or semiconductive films or sheets (hereinafter referred to as sheet materials) as materials for the purpose of preventing charging. . Examples of various parts using these sheets include an intermediate transfer sheet for transferring a toner image formed on a drum. In these sheets, the sheet material is formed so as to have an anisotropic molecular structure in which the surface resistance (ρs) is high and the volume resistance (ρv) is low. Further, since these resistance values greatly affect the function of the component, it is necessary to manage the electrical resistance in the thickness direction of the sheet material. As a device for measuring the electrical resistance, a resistance measuring instrument such as a tester or a digital multimeter that performs measurement by bringing a pair of test probes having a diameter of 20 to 50 mm in contact with both surfaces of a sheet material into contact is generally known. It has been.

  By the way, resistance measuring instruments such as testers and digital multimeters are of a type in which the tips of a pair of test probes are pressed against both sides of the sheet material, so the tip shape, contact angle, contact pressure, contact area, etc. of the test probe The measurement results tend to vary depending on the conditions. In particular, in a synthetic resin sheet production line, if it is applied to a sheet material that is continuously molded and transferred, the surface of the sheet material is damaged along with the transfer of the sheet material. It is difficult to measure its electrical resistance.

  The defective portion appearing on the sheet material is a small one that is less than a few millimeters in width, and its size and location are not determined, and it is difficult to find the defect.

In order to solve the above problem, Patent Document 1 (Japanese Patent Laid-Open No. 9-54126) discloses an apparatus for measuring electrical resistance by sandwiching a sheet material between upper and lower electrodes formed in a roll shape.
JP-A-9-54126

  However, this apparatus requires a roll-shaped electrode arranged over the entire width direction of the sheet material, and is a dedicated apparatus for measuring electrical characteristics of a sheet material having a specific width dimension. In addition, when the roll-shaped electrode is formed sufficiently long in the width direction of the sheet material and the sheet material is sandwiched, the roll-shaped electrode is deformed when a flexible sheet material is sandwiched, There is a possibility that a short circuit may occur due to contact between the two at a portion that does not contact the sheet.

  On the other hand, if the surface of the roll-shaped electrode is configured firmly, the sheet surface is damaged when sliding on the surface of the sheet material due to friction between the sheet material and the roll-shaped electrode. Since scratches on the surface of the sheet material are directly reflected in the formed image, it is not preferable that the transfer area of the toner image is damaged.

An object of the present invention is to provide a defect inspection method and a defect inspection apparatus for an intermediate transfer belt , which can perform continuous measurement and do not cause deterioration of the performance of the sheet material due to damage to the sheet surface. To do.

According to a first aspect of the present invention, extruded resin dispersed with conductive additives molded to be a sheet material of the molded ring, the surface of the intermediate transfer belt to which the toner image formed by the toner is transferred the defect inspection method using the measurement apparatus for inspecting defects of the intermediate transfer belt the measuring electrode is brought into contact for measuring the electrical resistance of the intermediate transfer belt,
The measuring electrodes are arranged so as to sandwich the intermediate transfer belt only in the thickness direction of the intermediate transfer belt outside the transfer area of the toner image of the end portion in the width direction of the intermediate transfer belt,
Continuously detecting the detection signal by continuously moving the intermediate transfer belt in a direction crossing the extrusion direction while applying a voltage to the electrode;
Based on the detection signal, high-pass the resistance change having a predetermined period of the detection signal accompanying the movement of the intermediate transfer belt ,
Provided is a defect inspection method characterized by integrating the high-pass resistance change and detecting the presence / absence of a defect in the intermediate transfer belt based on an integrated value of an output signal that suppresses a peak and suppresses high-frequency noise. .

According to a second aspect of the present invention, by extruding a resin dispersed with conductive additives consist sheet material which has been molded, for measuring the surface of the intermediate transfer belt to which the toner image formed by the toner is transferred A defect inspection apparatus for inspecting a defect of the intermediate transfer belt by contacting an electrode,
A transport unit that moves the intermediate transfer belt in a direction crossing the extrusion direction;
A measuring electrode disposed so as to sandwich the intermediate transfer belt in the thickness direction of the intermediate transfer belt only outside the transfer area of the toner image of the end portion in the width direction of the intermediate transfer belt,
While detecting the detection signal from the electrode by applying a voltage to the measurement electrode while moving the intermediate transfer belt by the transport unit,
The detection unit, based on the detection signal, a high-pass filter that high-passes a resistance change having a predetermined period of the detection signal accompanying the movement of the intermediate transfer belt ;
An integration circuit that integrates the high-pass resistance change and obtains an integral value of an output signal that suppresses a peak and suppresses high-frequency noise, and a defect in the intermediate transfer belt based on the integral value obtained by the integration circuit A defect inspection apparatus characterized by detecting the presence or absence of a defect is provided.

According to a third aspect of the present invention, there is provided the defect inspection apparatus according to the second aspect, wherein the electrode has a structure in which a protrusion contacting the sheet material is covered with a metal member via an insulating material. .

  Since the sheet material produced by extrusion molding is molded to have a molecular structure with anisotropy as described above, the sheet surface has a fault between the conductive particles along the pulling direction at the time of molding. Occurs. If this fault is large and continues to occur, a portion where the toner is not transferred is generated on the belt surface, and a so-called white streak is formed. Therefore, when the inspection is performed while moving the sheet material in the circumferential direction intersecting the extrusion direction, a streak-like defect can be detected even if only the vicinity in the width direction end portion is measured. Therefore, it is possible to inspect defects continuously while traveling in the circumferential direction, and damage to the sheet material due to contact with the electrodes can be kept only at the end portion, thereby more reliably inspecting the sheet material. In addition, the performance of the sheet material is not degraded.

  Since the fault is in an insulated state, it is in a state where electric charges are likely to accumulate. In this state, when the electrode to which a high voltage is applied is brought into contact at a constant speed, the defective portion functions as a capacitor, and the current is rapidly charged. To do. For this reason, when the volume resistance is measured, the defective portion rapidly decreases while the electric charge is charged. In the present invention, the presence or absence of a defect can be inspected by detecting this rapidly changed portion as a defect.

  Naturally, a gradual change in volume resistance is absorbed by the high-pass filter, and only a sudden change can be selected. Thereafter, the amount of change in the charge changes sharply, so that the level adjustment and high-frequency noise can be suppressed, so that a low-pass filter can be inserted to integrate the noise level to suppress the peak value. By managing the voltage level in this way, it is determined that the voltage value is below a predetermined threshold value.

  In addition, when the sheet material is an intermediate transfer belt for forming a toner image of an image generation apparatus such as a printer or a copying machine, the transfer region is made to have dust, scratches, etc. by placing the electrode outside the toner image transfer region. Can be prevented.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. The sheet material defect inspection method according to the present invention is a method for measuring the volume resistance value in the thickness direction of the seamless intermediate transfer belt 100 shown in FIG. As shown in FIG. 1, an intermediate transfer belt 100 is obtained by adding a conductive additive such as carbon to a mixed resin of polyphenylene sulfide resin and nylon resin (20% by weight or less) and uniformly dispersing it. It is made into a cylindrical shape by extruding from an extruding apparatus having an annular discharge port so that no joint is formed.

In the annular intermediate transfer belt 100 formed by extrusion, an additive such as carbon is dispersed as uniformly as possible in the resin so that the surface specific resistance is 10 ¹² Ω to 10 ⁷ Ω. On the other hand, it is difficult to completely and uniformly disperse carbon or the like, and the distribution of carbon may be uneven. A portion where the dispersion of carbon or the like is thin becomes a defective portion 102 of the intermediate transfer belt 100. Note that the defect portion 102 is in a state in which electric charges are likely to accumulate because the carbon is less dispersed and insulated.

  The defective portion of the intermediate transfer belt 100 is generally formed continuously in the extrusion direction indicated by the arrow 91 during the extrusion molding in FIG. As a result, as shown in FIG. 1, the defective portion 102 extends in the width direction of the belt main body 101 of the intermediate transfer belt and is formed in a streak shape. The streak-like defect portion has a width of approximately 1 mm to several mm.

  FIG. 2 is a schematic diagram showing a schematic configuration of the defect inspection apparatus for sheet material according to the embodiment of the present invention. The defect inspection apparatus 1 is provided with two support rollers 10 for winding the intermediate transfer belt and a tension roller 11 for taking up the slack of the intermediate transfer belt 100 wound between the support rollers 10.

  At least one of the support rollers 10 is connected to a drive device (not shown), rotates in response to the drive force of the drive device, and rotates the wound intermediate transfer belt as indicated by an arrow 90. be able to.

  The tension roller 11 can move up and down, and after the intermediate transfer belt 100 is wound around the support roller 10, the tension roller 11 is lowered to apply an appropriate tension to the intermediate transfer belt 100 wound around the support roller 10.

  The defect inspection apparatus 1 includes a positive electrode 13 and a negative electrode 14 that are in contact with each other with an intermediate transfer belt 100 wound between support rollers 10 sandwiched in the thickness direction. A voltage is applied from the DC power supply 15 between the electrode 13 and the electrode 14, and the volume resistance of the intermediate transfer belt 100 is measured by the detection unit 12 based on a current value signal flowing through the − electrode 14.

  FIG. 4 is a partial cross-sectional view showing the configuration of the negative electrode of the defect inspection apparatus of FIG. The electrode includes a protrusion 21 that contacts the surface on the image forming side of the intermediate transfer belt 100 and a main body portion 20 that supports the protrusion 21. The main body portion 20 is a container-like conductive member, and includes an insulating member 23 and an electrode tip portion 22 inside. The electrode tip 22 is formed with a projection 21 and is connected to an output line 24 that communicates with the detector 12.

  As described above, since the insulating member 23 and the main body 20 are provided around the electrode tip 22 having the protrusion 21 that directly contacts the intermediate transfer belt 100, it functions as a shield against noise from the outside during measurement. The resistance value can be measured with high accuracy.

  The + electrode 13 is configured to be thin in the running direction of the intermediate transfer belt 100 and long in the width direction, and the − electrode 14 is configured to be larger than the + electrode 13.

  As will be described later, the detection unit 12 determines the presence or absence of streak defects based on the volume resistance value of the intermediate transfer belt 100 calculated based on the current value signal, and determines the quality of the intermediate transfer belt 100 that is the inspection target. To do.

  The positions where the electrodes 13 and 14 are brought into contact with the intermediate transfer belt 100 are end portions in the width direction of the intermediate transfer belt 100 as shown in FIG. 3A. As described above, since the streak defect 102 of the intermediate transfer belt 100 extends over almost the entire region in the width direction of the intermediate transfer belt 100, the defect is measured by measurement at the end portion in the width direction of the intermediate transfer belt 100. be able to.

  FIG. 3B is a cross-sectional view illustrating a configuration of the intermediate transfer belt. The intermediate transfer belt 100 is provided with a transfer region 103 in which a toner image is formed at the center in the width direction, and non-transfer regions 104 are provided at both ends thereof. The transfer area 103 is an area for transferring the toner image of the intermediate transfer belt to a transfer surface 103a from a printing drum or the like, and transferring the toner image to a printing medium such as paper. It is required to be.

  In addition, the non-transfer area 104 is provided with a rubber travel assisting member 105 for assisting the rotational driving of the intermediate transfer belt 100 and a polyimide tape 106 for protecting the end of the intermediate transfer belt 100. It is done. In this region, even if the transfer surface 103a of the intermediate transfer belt is damaged, it is covered with the travel assisting member 105, the polyimide tape 106, and the like, so that the performance of the intermediate transfer belt 100 is not affected.

  In the defect inspection method for the intermediate transfer belt according to the present embodiment, the electrodes 13 and 14 are brought into contact with the outer region of the transfer region 103 before the travel assisting member 105 and the polyimide tape 106 are provided, so that the defect is detected. taking measurement. Even if the contact portion with the electrode is damaged by running the intermediate transfer belt 100 in a state where the electrodes 13 and 14 are in contact with each other, the portion can be cut and removed because it is an end portion in the width direction of the belt. Since the damage can be eliminated by covering with the travel assisting member 105 or the polyimide tape 106, the function of the intermediate transfer belt is not affected.

  Next, the defect inspection operation of the defect inspection apparatus according to the present embodiment will be described. When performing defect inspection, the intermediate transfer belt 100 wound around the support roller 10 and the tension roller 11 is rotationally driven as indicated by an arrow 90, and the current value obtained as the output value of the-electrode 14 is continuously measured. The volume resistance value is calculated based on the current value.

  FIG. 5 is a diagram showing a circuit configuration of the inspection unit 12 of the defect inspection apparatus of FIG. The inspection unit 12 has a circuit configuration as shown in FIG. 5. An input signal from the-electrode 14 is a voltage that can be inspected by subjecting a minute current flowing through the volume resistor 31 to IV conversion by the first amplification amplifier 32. Convert to a signal. FIG. 6A is an example of an output signal from the first amplification amplifier 32. When the defect portion D is present in this signal, the voltage of the defect portion D drops rapidly while charging the charge, and the waveform of the other portion changes gradually according to the gradual variation (change) of the molding portion. . Further, the entire waveform includes fluctuation noise when traveling on the belt surface.

  Next, the voltage value signal is inverted and amplified by the second amplifier 33 shown in FIG. Thereafter, a waveform other than a defective portion is removed by passing through a high-pass filter 34 that cancels a gradual change in volume resistance in the circumferential direction of the belt.

  This high-pass filter (cut-off frequency: 10 Hz to 100 Hz) removes the gradual fluctuation of the resistance value in the belt circumferential direction, which is manifested by the optimized traveling speed, in accordance with the intermediate transfer belt model, so that a defective portion of the intermediate transfer belt is obtained. Only the waveform can be detected. FIG. 6B shows an output waveform from the third amplifier 35 that has passed through the high-pass filter 34.

  Thereafter, when the defective portion is completed, the change in charge changes sharply. Therefore, a low-pass filter 36 is disposed to suppress instantaneous peaks and high-frequency noise. As a result, the peak value of the defective portion is integrated, and the waveform is shaped as the integrated value of the entire waveform. The non-defective product is determined by comparing the peak value (peak voltage value) of the defective portion with the allowable voltage value determined by the intermediate transfer belt of the allowable limit confirmed by the good product.

  Depending on the resolution of the product, it is determined that one defect is a non-defective product, but it may be determined that a defect is a defect when two consecutive defects occur in a short time (eg, 5 ms). . In this case, you may have the function which can detect and inspect the voltage value which each defect shows, and its space | interval.

  As described above, according to the present invention, the annular sheet material manufactured by the extrusion molding of the measurement object is continuously measured in order to measure the presence or absence of defects while rotating in the circumferential direction with the electrode in contact with the outside of the transfer region. The quality of the sheet material due to the defects generated in the shape can be inspected.

FIG. 3 is a schematic diagram illustrating a configuration of an intermediate transfer belt as an example of a sheet material to be inspected by the defect inspection apparatus of the present invention. It is a schematic diagram which shows schematic structure of the defect inspection apparatus of the sheet | seat material concerning embodiment of this invention. It is a figure which shows the position which the electrode of the defect inspection apparatus of FIG. 2 is made to contact an intermediate transfer belt. FIG. 3 is a cross-sectional view illustrating a configuration of an intermediate transfer belt. It is a partial cross section figure which shows the structure of-electrode of the defect inspection apparatus of FIG. It is a figure which shows the circuit structure of the test | inspection part of the defect inspection apparatus of FIG. 4 is an example of an output signal from the first amplification amplifier 32. It is an example of the output signal from which the fluctuation frequency was canceled. It is an example of the output signal from a test | inspection part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Defect inspection apparatus 10 Support roller 11 Tension roller 12 Inspection part 13 + Electrode 14-Electrode 15 DC power supply 20 Main body part 21 Projection 22 Electrode tip part 23 Insulating member 100 Intermediate transfer belt 101 Belt main body 102 Streak defect part 103 Transfer area 103a Transfer surface 104 Non-transfer area 105 Travel assist member 106 Polyimide tape

Claims (3)

Conductive additives by extruding a dispersed resin consists sheet material of the molded ring, the toner image formed by toner by contact with the measuring electrode on the surface of the intermediate transfer belt is transferred intermediate the defect inspection method for inspecting a defect of the intermediate transfer belt by using a measuring device for measuring the electrical resistance of the transfer belt,
The measuring electrodes are arranged so as to sandwich the intermediate transfer belt only in the thickness direction of the intermediate transfer belt outside the transfer area of the toner image of the end portion in the width direction of the intermediate transfer belt,
Continuously detecting the detection signal by continuously moving the intermediate transfer belt in a direction crossing the extrusion direction while applying a voltage to the electrode;
Based on the detection signal, high-pass the resistance change having a predetermined period of the detection signal accompanying the movement of the intermediate transfer belt ,
A defect inspection method, comprising: integrating the high-pass resistance change and detecting the presence or absence of a defect in the intermediate transfer belt based on an integrated value of an output signal in which peak suppression and high-frequency noise are suppressed. Conductive additives and extruding a dispersed resin consists sheet material which has been molded, the so abutting the measuring electrode on the surface of the intermediate transfer belt to which the toner image formed by the toner is transferred the intermediate transfer belt A defect inspection apparatus for inspecting defects of
A transport unit that moves the intermediate transfer belt in a direction crossing the extrusion direction;
A measuring electrode disposed so as to sandwich the intermediate transfer belt in the thickness direction of the intermediate transfer belt only outside the transfer area of the toner image of the end portion in the width direction of the intermediate transfer belt,
While detecting the detection signal from the electrode by applying a voltage to the measurement electrode while moving the intermediate transfer belt by the transport unit,
The detection unit, based on the detection signal, a high-pass filter that high-passes a resistance change having a predetermined period of the detection signal accompanying the movement of the intermediate transfer belt ;
An integration circuit that integrates the high-pass resistance change and obtains an integral value of an output signal that suppresses a peak and suppresses high-frequency noise, and a defect in the intermediate transfer belt based on the integral value obtained by the integration circuit A defect inspection apparatus characterized by detecting the presence or absence of a defect. 3. The defect inspection apparatus according to claim 2 , wherein the electrode has a configuration in which a protrusion contacting with the intermediate transfer belt is covered with a metal member via an insulating material.

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