JP4963936B2 - Image forming apparatus - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer that employs an electrophotographic system, and in particular, a transfer roller that is coated with a material having ion conductivity and transfers a toner image formed on a photoreceptor surface to a recording medium. And an image forming apparatus including a transfer unit including a heating unit that heats the transfer roller, and a heating control unit that controls the heating unit to heat the transfer roller to a target temperature.

  As described in Patent Document 1, in an image forming apparatus comprising: an image carrier that carries a developer image on the surface; and a transfer charging device that is disposed at a position facing the image carrier. A part of the recording medium is located in the transfer area between the image carrier and the transfer charging device, and the recording medium to which the developer image carried by the image carrier is to be transferred is downstream from the upstream side of the transfer area in the transport path. The conductivity of the portion of the recording medium holder that is located in the transfer area is higher than the conductivity of the portion of the recording medium holder that is located outside the transfer area. The recording medium holder is made of an ion conductive material, and heating means for heating a portion located in the transfer area of the recording medium holder to a predetermined temperature is provided. Including Image forming apparatus has been proposed which is characterized in that.

By heating the recording medium holder, which is blended with an ion conductive member having a characteristic that the electric resistance decreases as the temperature rises, using a heating unit that heats the recording medium holder at a predetermined heating temperature, Since the conductivity of the portion located in the transfer area of the recording medium holder is higher than the conductivity of the portion located outside the transfer area of the recording medium holder, it can be easily transferred to the transfer area of the recording medium holder. The electric conductivity of the portion located and the charge amount of the portion located in the transfer area of the recording medium are adjusted, and the electric resistance of the recording medium holder can be minimized, thereby preventing the occurrence of transfer scattering. .
JP 2003-76166 A

  In general, a recording medium holder made of an ion conductive material is controlled so that the recording medium holder is maintained at a predetermined temperature in order to secure a constant transfer current because the resistivity varies depending on the temperature. It is desirable to do. However, repeated heating and cooling of the recording medium holder promotes deterioration of the recording medium holder and shortens the life of the recording medium holder.

  Therefore, when the electrical resistance of the recording medium holder increases due to temperature fluctuations around the transfer roller, a constant transfer current is supplied from a large constant current source so that a current necessary for transfer can flow. In the case of the configuration, an expensive power source is required, and further, it is necessary to take measures for preventing abnormal discharge due to a high voltage.

  In view of the above problems, an object of the present invention is to increase the life of the transfer roller and increase the power consumption by heating the transfer roller to a predetermined temperature when it is determined that the transfer roller has deteriorated. Is to provide an image forming apparatus that can maintain a stable transfer characteristic.

In order to achieve the above object, a first characteristic configuration of an image forming apparatus according to the present invention is a transfer roller that is coated with a material having ion conductivity and transfers a toner image formed on the surface of a photoreceptor to a recording medium. An image forming apparatus comprising: a heating unit that heats the transfer roller; and a heating control unit that controls heating of the heating unit so that the transfer roller reaches a target temperature. A deterioration determination unit that determines deterioration of the transfer roller, and the transfer of the transfer roller by the deterioration determination unit without controlling the heating of the transfer roller by the heating control unit until it is determined by the deterioration determination unit that the transfer roller has deteriorated. The transfer roller is heated by the heating control means after it is determined that the roller has deteriorated .

  When performing transfer using a transfer roller coated with a material having ion conductivity, the inventor of the present application can achieve transfer characteristics even if there is a slight temperature fluctuation unless the material having ion conductivity is significantly deteriorated. It has been found that transfer can be performed without lowering. Therefore, it is possible to determine the deterioration of the transfer roller due to a change with time, and to heat the transfer roller to a predetermined temperature based on the result, so that the electric resistance value of the transfer roller can be lowered, and the transfer roller transfer The deterioration of characteristics can be prevented. Furthermore, since the transfer roller is always heated and is not repeatedly heated and cooled to reach the target temperature, it is possible to prevent the life of the transfer roller from being shortened.

  In the second characteristic configuration, as described in the second aspect, in addition to the first characteristic configuration described above, the deterioration determining unit measures a cumulative application time of the bias voltage to the transfer roller, and the cumulative characteristic is measured. The cumulative application time management means determines that the application time has deteriorated when the application time exceeds a predetermined time.

  According to the configuration described above, the time during which the transfer roller is used can be detected by measuring the cumulative application time of the bias voltage to the transfer roller. It is determined that the accumulated printing time has deteriorated when used for a predetermined time or more. By heating the transfer roller from the point of time when it is determined that it has deteriorated, power consumption can be reduced, and stable transfer characteristics can be maintained.

  In the third feature configuration, as described in claim 3, in addition to the first feature configuration described above, the deterioration determination unit counts the number of printed sheets, and the cumulative number of printed sheets is equal to or greater than a predetermined number. In other words, it is constituted by a cumulative number of printed sheet management means that is determined to have deteriorated.

  According to the configuration described above, by counting the number of printed sheets, it can be determined that the transfer roller has deteriorated when the cumulative number of printed sheets exceeds a predetermined number. By heating the transfer roller from the time when the accumulated number of printed sheets is used or more, power consumption can be reduced, and stable transfer characteristics can be maintained.

  In the fourth feature configuration, as described in claim 4, in addition to the first feature configuration described above, the deterioration determining unit measures a transfer current value to the transfer roller, and the transfer current value is determined. Is constituted by a transfer current value detecting means for determining that the battery has deteriorated when the current becomes equal to or less than a predetermined current value.

  A transfer current value to the transfer roller is measured, and it can be determined that the transfer roller has deteriorated when the transfer current value is equal to or greater than a predetermined current value. By heating the transfer roller when the transfer current value becomes equal to or higher than a predetermined current value, power consumption can be reduced and stable transfer characteristics can be maintained. In addition, since the transfer characteristics can be maintained without increasing the current value applied to the transfer roller, it is possible to maintain stable transfer characteristics without using a large constant current source that has a high cost affecting other devices. Can do.

  According to the fifth characteristic configuration, as described in the fifth aspect, in addition to the third or fourth characteristic configuration described above, the heating control unit may be configured so that the temperature near the transfer roller decreases below a predetermined temperature. In addition, the heating of the transfer roller is controlled.

  According to the above-described configuration, the temperature of the image forming apparatus becomes higher than a predetermined temperature in the vicinity of the transfer roller even if the heating unit is not heated due to the installation location of the image forming apparatus or the temperature inside the apparatus of the image forming apparatus. If it is determined that the transfer roller is deteriorated by the deterioration determining means, it is not necessary to heat the transfer roller. Therefore, by measuring the temperature near the transfer roller when the deterioration determination unit determines that the transfer roller is deteriorated, the transfer roller is heated only when the temperature near the predetermined temperature is lower than a predetermined temperature. By doing so, power consumption can be reduced.

  According to the present invention, in view of the above problems, when it is determined that the transfer roller has deteriorated, the transfer roller is heated to a predetermined temperature, thereby extending the life of the transfer roller and reducing power consumption. And an image forming apparatus capable of maintaining stable transfer characteristics can be provided.

  Hereinafter, as an image forming apparatus according to the present invention, as shown in FIG. 1, an embodiment of an image forming apparatus 100 including a transfer unit 1 will be described.

  The image forming apparatus 100 includes a drum-shaped photosensitive member 2, a charging unit 3 that uniformly charges the surface of the photosensitive member 2, and the photosensitive member 2 whose surface is uniformly charged by the charging unit 3. An optical scanning unit for forming an electrostatic latent image; a developing unit 4 for supplying toner to the surface of the photosensitive member 2 having an electrostatic latent image formed on the surface thereof; and forming a toner image on the surface of the photosensitive member 2; A transfer portion A including a transfer roller 5 for transferring a toner image to a recording medium and a heating unit 6; a cleaner 7 for removing toner adhering to the photoconductor 2 after the toner image is transferred to the recording medium; And image forming control means (not shown) for controlling each unit.

  As shown in FIG. 2A, the transfer roller 5 is composed of an aluminum tube covered with a material having ion conductivity. Examples of the material having ion conductivity include rubber and urethane materials. It is composed of a mixture of lauryltrimethylammonium, stearyltrimethylammonium, octadodecyltrimethylammonium and the like. The transfer roller is configured such that a high voltage of 5 kV to 6 kV is applied from a high voltage power source 5c controlled by the image formation control means.

  The heating means 6 includes a heater 6a disposed in the vicinity of the transfer roller 5, and the transfer roller 5 is controlled to be heated to a target temperature by a heating control means. The heating control means detects the temperature with a thermistor provided in the vicinity of the transfer roller 5, and controls the heating to the target temperature by turning on / off the energization of the heater 6a based on the detected temperature. Composed.

  The control unit of the image forming apparatus 100 is a CPU that controls the image forming apparatus 100 via an interface connected to each unit, a RAM that stores various control information, and a ROM that stores programs. It is configured.

  As shown in FIG. 3, the CPU includes the image forming control means 10, the heating control means 20, a deterioration determining means 30 for determining that the transfer roller has deteriorated, and the like.

  The image formation control unit 10 is configured to control the charging unit 3, the developing unit 4, the optical scanning unit 8, the recording medium transport unit 9, and the transfer roller 5 (high voltage power source 5c). Yes.

  When it is determined by the deterioration determination unit 30 that the transfer roller 5 has deteriorated, the heating control unit 20 measures a temperature near the transfer roller 5 by a temperature detection unit 6 c provided near the transfer roller 5. To do. The heating control unit 20 is configured to heat the transfer roller 5 to a target temperature by the heating unit 6 when the measured temperature is equal to or lower than a predetermined temperature. The predetermined temperature and the target temperature may be set at the same temperature, or may be set individually.

  The deterioration determination unit 30 counts the time during which the transfer roller 5 is applied by the image formation control unit 10 by using an application time counter. When the application time becomes equal to or longer than a predetermined time, the cumulative application time management unit 30a determines that the transfer roller 5 has deteriorated.

  When the printing process is performed, the surface of the photosensitive member 2 is uniformly charged by the charging unit 3 as shown in FIG. When the surface of the photoconductor 2 is charged, an electrostatic latent image to be transferred is formed on the surface of the photoconductor 2 by the optical scanning unit 8. When the electrostatic latent image is formed, the developing unit 4 applies toner to the surface of the photoreceptor 2 to form a toner image. The recording medium P is conveyed by the recording medium conveying means 9 so as to contact the surface of the transfer roller 5 and the surface of the photoreceptor 2. The toner image is transferred onto the recording medium P by the transfer roller 5 to which a bias voltage is applied from a high voltage power source 5c. When transferred, unnecessary toner applied to the photoreceptor 2 is removed from the cleaner 7.

  At this time, if the deterioration determining means 30 determines that the transfer roller 5 has deteriorated, the temperature detecting means 6b disposed in the vicinity of the transfer roller 5 detects the temperature near the transfer roller 5. If the temperature is not more than the predetermined temperature, the transfer roller 5 is heated by the heating means 6.

  Hereinafter, the operation of the deterioration determination process of the image forming apparatus 100 provided with the cumulative application time management unit 30a as the deterioration determination unit 30 will be described with reference to a flowchart.

  As shown in FIG. 4, when the image forming apparatus 100 starts a transfer process (SA1), a bias voltage is applied from the high voltage power source 5c to the transfer roller 5 by the image forming control means 10 (SA2). ). When the bias voltage starts to be applied, the printing time counter counts the application time and updates the application time counter (SA3). When the application time counter is updated, the cumulative application time management unit 30a compares the cumulative application time with a predetermined application time that is set, and if the cumulative application time is greater than the predetermined time (SA4 / Yes). The heating control means 20 measures the temperature in the vicinity of the transfer rotor by the temperature detection means 6b disposed in the vicinity of the transfer rotor 5 (SA5).

  When the measured temperature is lower than the predetermined temperature (SA5 / Yes), the heating control means 10 heats the transfer roller 5 to the target temperature by the heating means 6 (SA6), and the process ends.

  As another embodiment, as shown in FIG. 5, a case will be described in which the image forming apparatus 100 is configured to include an accumulated print number management unit 30 b as the deterioration determination unit 30.

  The cumulative number-of-printing-number managing unit 30b counts the number of sheets on which the recording medium P is printed by the transfer roller 5 using an applied number counter. When the applied number is equal to or greater than the predetermined number set in the cumulative applied number management unit 30b, for example, 100,000 or more, it is determined that the transfer roller 5 has deteriorated.

  When the heating control unit 20 determines that the transfer roller 5 has deteriorated by the cumulative print number management unit 30b, the temperature detection unit 6b provided in the vicinity of the transfer roller 5 detects the temperature near the transfer roller 5. Measure. The heating control unit 20 is configured to heat the transfer roller 5 from the heating unit 6 to a target temperature when the measured temperature is equal to or lower than a predetermined temperature. The predetermined temperature and the target temperature may be set at the same temperature, or may be set individually.

  Hereinafter, the operation of the deterioration determination process of the image forming apparatus 100 provided with the cumulative number of printed sheets management unit 30b as the deterioration determination unit 30 will be described with reference to a flowchart.

  When the image forming apparatus starts a transfer process as shown in FIG. 6 (SB1), a bias voltage is applied to the transfer roller 5 from the high-voltage power source 5c by the image formation control means 10 (SB2). . When the transfer roller 5 is applied and transfer (printing) is performed, the printed sheet counter counts the number of printed sheets and updates the printed sheet counter (SB3). When the applied number counter is updated, the cumulative printed number management unit 30b compares the cumulative printed number with the set predetermined number, and if the cumulative printed number is larger than the predetermined number (SB4 / Yes), The heating control means 20 measures the temperature in the vicinity of the transfer rotor 5 by the temperature detection means 6b arranged in the vicinity of the transfer rotor 5 (SB5).

  When the measured temperature is lower than the predetermined temperature (SB5 / Yes), the heating control unit 20 heats the transfer roller 5 to the target temperature by the heating unit 6 (SB6), and ends.

  Furthermore, as another embodiment, a case where the image forming apparatus 100 includes a transfer current value detecting unit 30c as the deterioration determining unit 30 will be described as shown in FIG.

  The transfer current value detection means 30 c measures the transfer current value to the transfer roller 5. When the transfer current value is equal to or greater than a predetermined current value, for example, 80 μA or less, the transfer current value detection unit 30c determines that the transfer roller 5 has deteriorated.

  The heating control unit 20 is configured to heat the transfer roller 5 to a target temperature from the heating unit 6 when the transfer current value detection unit 30c determines that the transfer roller 5 has deteriorated. .

  When the transfer current value is 80 μA or less, the transfer current value detection unit 30c determines that the transfer roller 5 has been reliably deteriorated. Therefore, the heating unit 6 is independent of the temperature near the transfer roller 5. Thus, the transfer roller 5 is heated.

  Hereinafter, the operation of the deterioration determination process of the image forming apparatus 100 including the transfer current value detecting unit 30c will be described with reference to a flowchart.

  When the image forming apparatus 100 starts a transfer process as shown in FIG. 8 (SC1), a bias voltage is applied to the transfer roller 5 by the image forming control means 10 (SC2). When the transfer roller 5 is applied, the bias voltage is detected (SC3). The transfer current value detection means 30c compares the detected transfer current with a set predetermined current value, and when the transfer current value is lower than the predetermined current value (SC4 / Yes), the heating control means 20 Then, the transfer roller 5 is heated to the target temperature by the heating means 6 (SC5), and the process ends.

  In the above-described embodiment, the transfer roller 5 is configured by covering an aluminum base tube 5a with a material 5c having ion conductivity, and the material 5c having ion conductivity may be rubber or urethane material or lauryl. Although what was comprised using what mix | blended trimethylammonium, stearyltrimethylammonium, octadodecyltrimethylammonium, etc. was demonstrated, the said transfer roller 5 has the ionic conductivity which has an electrical property in which an electrical resistance reduces as it becomes high temperature. However, the material is not limited to this.

  Each of the above-described embodiments is merely an example of the present invention, and the scope of the present invention is not limited by the description. The specific configuration of each part is appropriately selected within the scope of the effects of the present invention. Needless to say, it can be changed.

Explanatory drawing of the main part of the image forming apparatus in the present invention (A) principal part explanatory drawing of a transfer part, (b) principal part explanatory drawing of an image forming apparatus. System block diagram of image forming apparatus Flowchart used to explain degradation determination processing System block diagram of image forming apparatus Flowchart used to explain degradation determination processing System block diagram of image forming apparatus Flowchart used to explain degradation determination processing

1: Transfer unit 2: Photoconductor 3: Charging unit 4: Developing unit 5: Transfer roller 5a: Aluminum tube 5b: Material 5c having ion conduction: High voltage power source 6: Heating unit 6a: Heater 6b: Temperature detecting unit 7: Cleaner 8: Optical scanning means 9: Recording medium transport means 10: Image formation control means 20: Heating control means 30: Degradation determination means 30a: Cumulative application time management means 30b: Cumulative print number management means 30c: Transfer current value detection means 100 : Image forming apparatus P: Recording medium

Claims (5)

Is coated with a material having ion conductivity, a transfer roller for transferring the toner image formed on the photosensitive member surface to a recording medium, a heating means for heating the transfer roller, the said transfer roller so that the target temperature An image forming apparatus including a transfer unit including a heating control unit that controls heating of the heating unit,
Deterioration determination means for determining deterioration of the transfer roller, and the deterioration determination means without heating control of the transfer roller by the heating control means until the deterioration determination means determines that the transfer roller has deteriorated. An image forming apparatus that controls the heating of the transfer roller by the heating control unit after it is determined that the transfer roller has deteriorated .   The degradation determination unit includes a cumulative application time management unit that measures the cumulative application time of the bias voltage to the transfer roller and determines that the deterioration has occurred when the cumulative application time becomes equal to or longer than a predetermined time. The image forming apparatus according to 1.   The image forming apparatus according to claim 1, wherein the deterioration determination unit is configured by a cumulative print number management unit that counts the number of prints and determines that the print has deteriorated when the cumulative print number exceeds a predetermined number.   2. The transfer current value detecting means, wherein the deterioration determining means measures a transfer current value to the transfer roller, and determines that the transfer current value has deteriorated when the transfer current value becomes a predetermined current value or less. Image management equipment. The image forming apparatus according to claim 2, wherein the heating control unit controls the heating of the transfer roller when a temperature in the vicinity of the transfer roller falls below a predetermined temperature.

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