JP2019020468A - Image forming apparatus - Google Patents

Abstract

To prevent the occurrence of dew condensation inside the apparatus with a simple configuration.SOLUTION: An image forming apparatus 100 forming an image on a sheet 16 comprises: a temperature and humidity sensor 21 that detects the temperature and humidity inside the apparatus; a fan 18 that introduces outside air to the inside of the apparatus; and a CPU 20 that controls the fan 18 to prevent moisture in the outside air introduced to the inside of the apparatus from being condensed on the basis of the temperature and humidity inside the apparatus detected for every predetermined time and a change in temperature over time.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus such as a printer, a copier, a facsimile, or a complex machine thereof that prevents condensation inside the apparatus.

  2. Description of the Related Art Conventionally, an electrophotographic apparatus such as a printer, a copier, a facsimile, or a multifunction machine of these has been provided with an intake fan that cools by introducing outside air into a unit that may be at a high temperature such as a power source. Such an intake fan starts operating when the electrophotographic apparatus is powered on.

  When the electrophotographic apparatus is cooled by cold air such as at night in a cold region, heating and humidification are started in the environment where the electrophotographic apparatus is installed, and the power is turned on before the apparatus is sufficiently warmed In this case, the outside air that has become hot and humid by the intake fan flows into the apparatus. At this time, in the electrophotographic apparatus, dew condensation may occur due to the outside air hitting the metal parts, the high-voltage substrate and the photoconductor inside the apparatus which has been cooled down.

  When dew condensation occurs on metal parts or high-voltage boards inside the apparatus, the apparatus main body may be damaged due to rust of metal parts or high-voltage bias leak from the high-pressure board. Further, when dew condensation occurs on the photoconductor, image blur called image flow occurs. As described above, in an electrophotographic apparatus, when excessively high temperature and high humidity outside air is taken into the apparatus, dew condensation occurs and an image flow is generated. Therefore, in the electrophotographic apparatus, it is necessary to perform optimum fan control for the intake fan.

  Patent Document 1 discloses a device that displays the temperature and humidity inside the device and inside the device, and displays whether or not condensation occurs.

  Patent Document 2 discloses an electrophotographic apparatus provided with a sensor for measuring the temperature and humidity of the outside air and a sensor for measuring the surface temperature of the photoreceptor. Such an electrophotographic apparatus stops the cooling fan when the temperature difference between the outside air temperature and the surface temperature of the photoreceptor exceeds the dew condensation limit point in the outside air humidity. Then, the electrophotographic apparatus of Patent Document 2 increases the temperature inside the apparatus by driving a fixing device heater, and enters an image forming preparation operation after determining that no condensation occurs.

JP 2007-334267 A JP 2004-013015 A

  However, Patent Document 1 has a problem in that dew condensation occurs on a metal part, a high-pressure board, or a photoconductor inside the apparatus because the temperature difference and humidity difference between the outside of the apparatus and the inside of the apparatus cannot be suppressed. Further, Patent Document 2 has a problem that both an outside air temperature detecting unit and a photoreceptor temperature detecting unit are required.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus capable of preventing the formation of condensation inside the apparatus with a simple configuration.

  An image forming apparatus according to the present invention is an image forming apparatus for forming an image on a recording material, the detecting means for detecting temperature and humidity inside the apparatus, the air flow generating means for introducing outside air into the apparatus, And control means for controlling the airflow generation means based on the temperature and humidity inside the apparatus and the change over time of the temperature.

  According to the present invention, it is possible to prevent dew condensation from occurring inside the apparatus with a simple configuration.

1 is a schematic diagram of an image forming apparatus according to Embodiment 1 of the present invention. It is a flowchart of the dew condensation prevention process which concerns on Embodiment 1 of this invention. It is a figure which shows transition of the temperature and humidity at the time of performing the first half of the dew condensation prevention process which concerns on Embodiment 1 of this invention. It is a figure which shows transition of the temperature and humidity at the time of performing the second half of the dew condensation prevention process which concerns on Embodiment 1 of this invention. It is a figure which shows the table which concerns on Embodiment 1 of this invention. It is a figure which shows transition of the temperature and humidity at the time of performing the dew condensation prevention process which concerns on Embodiment 1 of this invention compared with the past. FIG. 6 is a schematic diagram of an image forming apparatus according to Embodiment 2 of the present invention. FIG. 6 is a schematic diagram of an image forming apparatus according to Embodiment 3 of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
<Configuration of image forming apparatus>
The configuration of the image forming apparatus 100 according to Embodiment 1 of the present invention will be described in detail with reference to FIG.

  The image forming apparatus 100 forms an image on a sheet 16 as a recording material. The image forming apparatus 100 includes a photosensitive drum 1, a charging unit 2, an exposure unit 3, a developing unit 4, a transfer roller 5, a separation static elimination needle 6, a cleaner 7, and a conveyance roller 8. Yes. Further, the image forming apparatus 100 includes a registration roller pair 10, a paper discharge roller 13, a fixing unit 14, a paper feed roller 15, and a paper cassette 17. Further, the image forming apparatus 100 includes a memory 19, a CPU 20, a temperature / humidity sensor 21, a power supply control unit 22, a fan power supply 23, and a timer 24.

  The surface of the photosensitive drum 1 as an image carrier is uniformly charged by the charging unit 2. An electrostatic latent image is formed on the photosensitive drum 1 by exposure by the exposure unit 3 after charging. A toner image as a developer image is formed on the photosensitive drum 1 by developing the toner from the developing unit 4 by adhering to the electrostatic latent image.

  The charging unit 2 is a conductive member whose electric resistance value changes depending on temperature and humidity. The charging unit 2 rotates in contact with the rotationally driven photosensitive drum 1 with a predetermined pressing force. The charging unit 2 applies a charging bias to uniformly charge the surface of the photosensitive drum 1 with a predetermined polarity and potential. Here, the charging bias is exemplified by a predetermined DC voltage (DC charging method) or a voltage (AC + DC charging method) obtained by superimposing a predetermined DC voltage and a predetermined AC voltage. In addition, the predetermined polarity and potential are exemplified here as −500 to −800V. The charging unit 2 can be configured to uniformly charge the photosensitive drum 1 other than the contact charging roller or the contact charging roller.

  The exposure unit 3 performs image exposure on the surface of the photosensitive drum 1 after charging based on image information input from an image reading device or the like (not shown), thereby removing the charge on the exposed portion of the surface of the photosensitive drum 1. Thus, an electrostatic latent image is formed on the photosensitive drum 1. Here, image exposure is exemplified by scanning exposure with a semiconductor laser (wavelength 780 nm) or exposure with an LED array. The exposure unit 3 can use a method capable of exposing the photosensitive drum 1 other than the semiconductor laser and the LED array.

  The developing unit 4 has a developing sleeve, and the developing sleeve to which a developing bias is applied carries toner, and attaches toner to the electrostatic latent image formed on the surface of the photosensitive drum 1 from the developing sleeve. Thus, a toner image is formed on the photosensitive drum 1 and the electrostatic latent image is developed. Here, the developing bias is exemplified by a voltage (AC + DC developing system) in which a predetermined DC voltage and a predetermined AC voltage are superimposed.

  Examples of the developing method in the developing unit 4 include a one-component reversal jumping developing method, a one-component contact developing method, a two-component contact developing method, and a two-component non-contact developing method. The one-component reversal jumping development method is a development method using a one-component magnetic negative toner. The one-component contact development method is a method in which development is performed in contact with the photosensitive drum 1. The two-component contact development method is a method in which a magnetic carrier is mixed with toner, and the toner is conveyed by magnetic force and developed in contact with the photosensitive drum 1. The two-component non-contact developing method is a method for developing two-component toner in a non-contact state with respect to the photosensitive drum 1.

  The transfer roller 5 includes a metal shaft body and a conductive foam layer formed on the outer periphery of the metal shaft body. The transfer roller 5 is in contact with the photosensitive drum 1 to form a transfer nip. The transfer roller 5 is a conductive member whose electric resistance value changes depending on temperature and humidity.

  The transfer roller 5 applies a predetermined DC voltage having a polarity opposite to the polarity of the toner at a timing when the sheet 16 is conveyed from the registration roller pair 10 to the transfer nip, and thereby a toner image attached to the photosensitive drum 1. Are sequentially electrostatically transferred onto the paper 16. Here, the predetermined DC voltage is +1 to 5 KV. Examples of the transfer method in the transfer roller 5 include a contact transfer roller method in contact with the photosensitive drum 1 or an intermediate transfer belt method in which a toner image is transferred to a transfer belt made of ITB and then transferred to a sheet 16.

  The separation charge eliminator 6 separates the paper 16 on which the toner image is transferred from the photosensitive drum 1.

  The cleaner 7 removes toner remaining on the surface of the photosensitive drum 1 without being transferred to the paper 16.

  The transport roller 8 transports the paper 16 fed by the paper feed roller 15 toward the registration roller pair 10.

  The registration roller pair 10 rotates in accordance with the toner image formed on the photosensitive drum 1 and supplies the paper 16 conveyed by the conveyance roller 8 toward the transfer nip.

  The paper discharge roller 13 discharges the paper 16 conveyed from the fixing unit 14.

  The fixing unit 14 includes a heating member (not shown) that heats the toner, a fixing pressure roller 11 that presses the fixing film 12 to form a fixing nip, and a fixing film 12 that is a cylindrical rotating body including the heating member. It is equipped with. The fixing unit 14 fixes the toner image on the paper 16 by heating the paper 16 conveyed from the transfer nip at the fixing nip. The fixing unit 14 conveys the paper 16 on which the toner image is fixed toward the paper discharge roller 13. Examples of the fixing method in the fixing unit 14 include an on-demand fixing method, a heat roller method, and an electromagnetic induction heating method.

  The paper feed roller 15 feeds the paper 16 stored in the paper cassette 17 to the transport roller 8.

  The paper cassette 17 stores paper 16.

  The fan 18 serving as an airflow generating unit operates when electric power is supplied from the fan power source 23 and introduces outside air into the image forming apparatus 100. The fan 18 stops its operation when the supply of power from the fan power source 23 is stopped, and stops the introduction of the outside air into the image forming apparatus 100.

  The memory 19 stores in advance a table in which relative humidity (hereinafter simply referred to as “humidity”), temperature, and moisture content in the air are associated with each other. The memory 19 stores the detection result of the temperature / humidity sensor 21 under the control of the CPU 20.

  The CPU 20 as a control unit performs control for causing the timer 24 to measure time, and performs control for causing the memory 19 to store the detection result input from the temperature / humidity sensor 21 every predetermined time measured by the timer 24.

  The CPU 20 estimates the temperature inside the image forming apparatus 100 after a predetermined time from the detection result of the temperature / humidity sensor 21 stored in the memory 19.

  Based on the table stored in the memory 19 and the estimated temperature inside the apparatus, the CPU 20 obtains a target temperature at which dew condensation that is higher than the dew point temperature of the outside air does not occur, and the target temperature obtained after the predetermined time has elapsed. The power supply control unit 22 is controlled to reach the temperature.

  A temperature / humidity sensor 21 serving as a detection unit detects the temperature and humidity inside the image forming apparatus 100 and outputs the detection result to the CPU 20.

  The power supply control unit 22 performs control to turn on or off the fan power supply 23 under the control of the CPU 20.

  The fan power supply 23 is turned on or off under the control of the power supply control unit 22. The fan power supply 23 supplies power to the fan 18 when turned on, and stops supplying power to the fan 18 when turned off.

  The timer 24 measures time under the control of the CPU 20.

<Condensation prevention treatment>
The dew condensation prevention process according to the first embodiment of the present invention will be described in detail with reference to FIGS. The table shown in FIG. 5 associates temperature, humidity, and absolute water content.

  The condensation prevention process shown in FIG. 2 is started when a main body power supply (not shown) of the image forming apparatus 100 is turned on.

  First, the temperature / humidity sensor 21 detects the temperature and humidity inside the apparatus (S1).

  Next, the CPU 20 stores the detection result of the temperature / humidity sensor 21 input from the temperature / humidity sensor 21 in the memory 19 a predetermined number of times at regular time intervals measured by the timer 24 (S2). The fixed time is exemplified here as 5 minutes. The predetermined number of times is exemplified here as three times.

  Specifically, as shown in FIG. 3, the CPU 20 stores in the memory 19 the detection result first detected by the temperature / humidity sensor 21 when the image forming apparatus 100 is turned on when the main body is turned on. Then, the CPU 20 stores the detection results of the temperature / humidity sensor 21 in the memory 19 after 5 minutes from the time of turning on the power of the main body and 10 minutes after the power of the main body is turned on. Note that the CPU 20 may start a process of storing the detection result of the temperature / humidity sensor 21 in the memory 19 when a predetermined time has elapsed since the main body was turned on.

  Next, based on the detection result of the temperature / humidity sensor 21 stored in the memory 19, the CPU 20 calculates the amount of temperature change per predetermined time as the temperature change over time (S3).

  Next, the CPU 20 estimates the temperature inside the apparatus after the predetermined time T1 has elapsed based on the calculated temperature change amount (S4). Here, the predetermined time T1 is 20 minutes.

  Specifically, as shown in FIG. 3, the CPU 20 estimates the internal temperature of the apparatus 20 minutes after the main power is turned on as 9 ° C. based on the calculated temperature change amount. By calculating the amount of temperature change using the detection result of the temperature / humidity sensor 21 when the main body is turned on, the amount of temperature change from a state in which the temperature inside the apparatus is substantially equal to the temperature of the outside air can be calculated. Thereby, it is possible to prevent the inside of the apparatus from condensing before the control of the fan 18 is started.

  Next, CPU20 calculates | requires the absolute moisture content matched with the temperature estimated in step S4 and the humidity 100% in the temperature in the table memorize | stored in the memory 19 (S5).

  Next, the CPU 20 sets a temperature higher than the dew point temperature associated with the obtained absolute moisture content in the table stored in the memory 19 as the target temperature, and associates it with the obtained absolute moisture content. The humidity below the set humidity is set as the target humidity (S6).

  In the case of FIG. 3, the absolute water content when the temperature is 9 ° C. and the humidity is 100% is 6.7 g / kgD. A. Therefore, the absolute water content is 6.7 g / kg D.D. A. When the above outside air is introduced into the image forming apparatus 100, condensation occurs inside the apparatus. For example, when a target temperature of 20 ° C. and a target humidity of 60% are set, the absolute water content is 8.8 g / kg D.D. A. 6.7 g / kg D. A. As a result, condensation occurs inside the apparatus.

  Therefore, the CPU 20 has an absolute water content of 6.7 g / kg D.D. A. A combination of temperature and humidity that is less than the temperature is set as the target temperature and humidity.

  For example, the CPU 20 has an absolute water content of 6.7 g / kgD. A. Less than 6.5 g / kg D.D. A. A target temperature of 10 ° C. and a target humidity of 90% are set. Alternatively, the CPU 20 has an absolute water content of 6.7 g / kg D.D. A. Less than 6.6 g / kg D.D. A. A target temperature of 11 ° C. and a target humidity of 85% are set. Alternatively, the CPU 20 has an absolute water content of 6.7 g / kg D.D. A. Less than 6.2 g / kg D.D. A. A target temperature of 12 ° C. and a target humidity of 75% are set. Alternatively, the CPU 20 has an absolute water content of 6.7 g / kg D.D. A. Less than 6.3 g / kg D.D. A. A target temperature of 13 ° C. and a target humidity of 65% are set.

  Here, when setting the target temperature of 10 ° C. and the target humidity of 90%, it is necessary to operate the fan 18 so as to increase the temperature inside the apparatus by 1 ° C., but the temperature inside the apparatus and the temperature of the outside air The difference cannot be eliminated. On the other hand, the absolute water content is 6.4 g / kg D.D. A. When the target temperature 18 ° C. and the target humidity 50% are set, the fan 18 may be operated so as to increase the temperature inside the apparatus by 9 ° C.

  Accordingly, the CPU 20 turns on the fan 18 by setting the target temperature 20 minutes after the main power is turned on to 18 ° C. and the target humidity 50%. Thereby, it is possible to prevent condensation within the apparatus.

  Next, the CPU 20 determines whether or not the temperature and humidity detected by the temperature and humidity sensor 21 (detected temperature and humidity) are equal to or higher than the set target temperature and target humidity (target temperature and humidity) (S7).

  When the temperature and humidity detected by the temperature / humidity sensor 21 are lower than the set target temperature and target humidity (S7: No), the CPU 20 determines that the temperature and humidity are likely to cause condensation. In this case, the CPU 20 controls the fan power source 23 to turn off the fan 18 to stop the operation of the fan 18 (S8), thereby stopping the introduction of the outside air into the apparatus, and then in step S7. Process.

  On the other hand, when the temperature and humidity detected by the temperature / humidity sensor 21 are equal to or higher than the set target temperature and target humidity (S7: Yes), the CPU 20 determines that the temperature and humidity do not cause condensation. In this case, the CPU 20 controls the fan power supply 23 to turn on the fan 18 and operate the fan 18 (S9), thereby introducing outside air into the apparatus.

  Here, in the case where the temperature and humidity of the outside air continue to rise, when the fan 18 is controlled under the same conditions as before the predetermined time T1 after the predetermined time T1 in step S4, dew condensation occurs inside the apparatus. It can happen. Therefore, the CPU 20 stores the detection result of the temperature / humidity sensor 21 input from the temperature / humidity sensor 21 in the memory 19 a predetermined number of times every predetermined time measured by the timer 24 after the elapse of the predetermined time in step S4. The fixed time is exemplified here as 5 minutes. The predetermined number of times is exemplified here as three times.

  Specifically, as shown in FIG. 4, the CPU 20 detects the detection result of the temperature / humidity sensor 21 20 minutes after the main body power is turned on, 25 minutes after the main body power is turned on, and 30 minutes after the main body power is turned on. Is stored in the memory 19.

  Next, the CPU 20 calculates a change amount per predetermined time as a temperature change with time based on the detection result of the temperature / humidity sensor 21 stored in the memory 19, and based on the calculated change amount, the predetermined time T2 is calculated. The temperature inside the apparatus after (T1 <T2) has elapsed is estimated (S10). Here, the predetermined time T2 is 40 minutes.

  Specifically, as shown in FIG. 4, the CPU 20 estimates the internal temperature of the apparatus after 40 minutes from the time of turning on the main body as 22 ° C. based on the calculated change amount.

  Next, CPU20 calculates | requires the absolute moisture content matched with the temperature estimated in step S10 and the humidity 100% in the temperature in the table shown in FIG. 5 memorize | stored in the memory 19 (S11).

  Next, the CPU 20 sets a temperature higher than the dew point temperature associated with the obtained absolute moisture content in the table stored in the memory 19 as the target temperature, and associates it with the obtained absolute moisture content. Humidity lower than the existing humidity is set as the target humidity (S12).

  In the case of FIG. 4, the absolute water content when the temperature is 22 ° C. and the humidity is 100% is 16.8 g / kgD. A. Therefore, the absolute water content is 16.8 g / kg D.D. A. When the above outside air is introduced into the image forming apparatus 100, condensation occurs inside the apparatus. For example, when a target temperature of 33 ° C. and a target humidity of 90% are set, the absolute water content is 29.6 g / kg D.D. A. 16.8 g / kg D. A. As a result, condensation occurs inside the apparatus.

  Therefore, the CPU 20 has an absolute water content of 16.8 g / kg D.D. A. A combination of temperature and humidity that is less than the temperature is set as the target temperature and humidity. For example, the CPU 20 has an absolute water content of 16.8 g / kgD. A. Less than 14.1 g / kg D.D. A. A target temperature of 25 ° C. and a target humidity of 70% are set.

  Therefore, the CPU 20 sets the target temperature 40 minutes after the main power is turned on to 25 ° C. and the target humidity to 70%, and turns on the fan 18. Thereby, it is possible to prevent condensation within the apparatus.

  Next, the CPU 20 determines whether or not the temperature and humidity detected by the temperature and humidity sensor 21 (detected temperature and humidity) are the set target temperature and target humidity (target temperature and humidity) (S13).

  When the temperature and humidity detected by the temperature / humidity sensor 21 are different from the set target temperature and target humidity (S13: No), the CPU 20 determines that the temperature and humidity are likely to cause condensation. In this case, the CPU 20 controls the fan power supply 23 to turn off the fan 18 to stop the operation of the fan 18 (S14), thereby stopping the introduction of the outside air into the apparatus, and then in step S13. Process.

  On the other hand, if the temperature and humidity detected by the temperature / humidity sensor 21 are the set target temperature and target humidity (S13: Yes), the CPU 20 determines that the temperature and humidity do not cause condensation. In this case, the CPU 20 controls the fan power supply 23 to turn on the fan 18 to operate the fan 18 (S15), thereby introducing outside air into the apparatus.

  Next, the CPU 20 determines whether or not the temperature estimated in step S4 (estimated temperature after 20 minutes) is equal to or higher than the temperature estimated in step S10 (estimated temperature after 40 minutes) (S16).

  When the temperature estimated in step S4 is lower than the temperature estimated in step S10 (S16: No), the CPU 20 increases the temperature and humidity inside the apparatus between the elapse of the predetermined time T1 and the elapse of the predetermined time T2. Can be judged as continuing. In this case, the CPU 20 returns to the process of step S1.

  On the other hand, when the temperature estimated in step S4 is equal to or higher than the temperature estimated in step S10 (S16: Yes), the CPU 20 determines the temperature and humidity inside the apparatus between the predetermined time T1 and the predetermined time T2. It can be judged that the rise in In this case, the CPU 20 ends the condensation prevention process.

  Thus, since the fan 18 is controlled so as to achieve the target temperature and target humidity set using the table, the dew condensation prevention process can be easily executed.

  FIG. 6 compares the changes in temperature and humidity inside the apparatus in a situation where the installation environment of the image forming apparatus 100 rises from a temperature of 5 ° C. and a humidity of 10% to a temperature of 30 ° C. and a humidity of 80% in 45 minutes. It shows.

  From FIG. 6, conventionally, changes in temperature and humidity inside the apparatus do not follow changes in temperature and humidity outside the apparatus. For this reason, conventionally, for example, when 45 minutes later, outside air having a temperature of 30 ° C. and a humidity of 80% is taken into the apparatus having a temperature of 10 ° C., the outside air is rapidly cooled, so that the absolute moisture content of the outside air is saturated. Condensation occurs beyond If the image forming apparatus is used with condensation, the main body of the apparatus is damaged due to leakage of a high voltage bias or rusting of metal parts. Conventionally, the time required for eliminating the difference between the temperature and humidity outside the apparatus and the temperature and humidity inside the apparatus is about 160 minutes.

  In contrast, in this embodiment, outside air is taken into the apparatus so that condensation does not occur, so that the temperature and humidity outside the apparatus and the temperature and humidity inside the apparatus are the same in the shortest time while preventing condensation. can do. The image forming apparatus 100 according to the present embodiment can reduce the time required for eliminating the difference between the temperature and humidity outside the apparatus and the temperature and humidity inside the apparatus to 40 minutes. In addition, since the fan 18 is operated little by little so as not to cause dew condensation, the problem of temperature rise inside the apparatus when the fan 18 is completely stopped, and the problem such as image flow when dew condensation are eliminated, Can be achieved.

  As described above, according to the present embodiment, by controlling the fan 18 based on the temperature and humidity inside the apparatus and the temporal change of the temperature, it is possible to prevent dew condensation from occurring inside the apparatus with a simple configuration. it can.

  Further, according to the present embodiment, the fan 18 is controlled based on the temperature and humidity inside the apparatus detected every predetermined time so that the outside air introduced into the apparatus does not condense. It is possible to ensure that no condensation occurs.

(Embodiment 2)
<Configuration of image forming apparatus>
The configuration of the image forming apparatus 200 according to Embodiment 2 of the present invention will be described in detail with reference to FIG.

  7, parts having the same configuration as in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

  The image forming apparatus 200 includes a photosensitive drum 1, a charging unit 2, an exposure unit 3, a developing unit 4, a transfer roller 5, a separation static elimination needle 6, a cleaner 7, and a conveyance roller 8. Yes. The image forming apparatus 200 includes a registration roller pair 10, a paper discharge roller 13, a fixing unit 14, a paper feed roller 15, and a paper cassette 17. Further, the image forming apparatus 200 includes a memory 19, a power supply control unit 22, a fan power supply 23, a timer 24, and a CPU 201.

  The fan 18 operates when electric power is supplied from the fan power source 23 and introduces outside air into the image forming apparatus 200.

  The CPU 20 acquires a detection result of a current flowing through the charging unit 2 or a voltage of the charging unit 2 when a charging bias is applied to the charging unit 2 as a detecting unit, and based on the acquired detection result, Detect temperature and humidity. For example, the CPU 20 associates the current, voltage, and humidity stored in the memory 19 with each other in association with the acquired current or voltage detection result in the table in which the current is associated with temperature and humidity, or in the table in which the voltage is associated with temperature and humidity. Find the temperature and humidity.

  The CPU 20 performs control to cause the timer 24 to measure time, and performs control to store the detection result of the temperature and humidity inside the apparatus in the memory 19 a predetermined number of times for every predetermined time measured by the timer 24. Since the configuration of the CPU 20 other than the above is the same as the configuration of the CPU 20 of FIG.

  The dew condensation prevention process according to the present embodiment is the same process as in FIG.

  Thus, according to the present embodiment, in addition to the effects of the first embodiment, the temperature and humidity inside the apparatus are detected from the current flowing through the charging unit 2 to which the charging bias is applied or the voltage of the charging unit 2. Therefore, the temperature and humidity sensor can be dispensed with and inexpensive.

(Embodiment 3)
<Configuration of image forming apparatus>
The configuration of the image forming apparatus 300 according to Embodiment 3 of the present invention will be described in detail with reference to FIG.

  8, parts having the same configuration as in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

  The image forming apparatus 300 includes a photosensitive drum 1, a charging unit 2, an exposure unit 3, a developing unit 4, a transfer roller 5, a separation static elimination needle 6, a cleaner 7, and a conveyance roller 8. Yes. The image forming apparatus 200 includes a registration roller pair 10, a paper discharge roller 13, a fixing unit 14, a paper feed roller 15, and a paper cassette 17. Further, the image forming apparatus 200 includes a memory 19, a power supply control unit 22, a fan power supply 23, a timer 24, and a CPU 201.

  The fan 18 operates when electric power is supplied from the fan power source 23 and introduces outside air into the image forming apparatus 300.

  The CPU 20 acquires a detection result of a current flowing through the transfer roller 5 or a voltage of the transfer roller 5 when a transfer bias is applied to the transfer roller 5 serving as a detection unit, and based on the acquired detection result, Detect temperature and humidity. For example, the CPU 20 associates the current, voltage, and humidity stored in the memory 19 with each other in association with the acquired current or voltage detection result in the table in which the current is associated with temperature and humidity, or in the table in which the voltage is associated with temperature and humidity. Find the temperature and humidity.

  The CPU 20 performs control to cause the timer 24 to measure time, and performs control to store the detection result of the temperature and humidity inside the apparatus in the memory 19 a predetermined number of times for every predetermined time measured by the timer 24. Since the configuration of the CPU 20 other than the above is the same as the configuration of the CPU 20 of FIG.

  The dew condensation prevention process according to the present embodiment is the same process as in FIG.

  Thus, according to the present embodiment, in addition to the effects of the first embodiment, the temperature and humidity inside the apparatus are detected from the current flowing through the transfer roller 5 to which a bias is applied or the voltage of the transfer roller 5. Therefore, the temperature / humidity sensor is unnecessary and can be made inexpensive.

  In addition, although embodiment of invention was described concretely, it cannot be overemphasized that this invention can be variously deformed in the range which is not limited to the said embodiment and does not deviate from the summary.

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging part 3 Exposure part 4 Developing part 5 Transfer roller 6 Separation static elimination needle 7 Cleaner 8 Conveyance roller 10 Registration roller pair 11 Fixing pressure roller 12 Fixing film 13 Paper discharge roller 14 Fixing part 15 Paper feed roller 16 Paper 17 Paper cassette 18 Fan 19 Memory 20 CPU
DESCRIPTION OF SYMBOLS 21 Temperature / humidity sensor 22 Power supply control part 23 Fan power supply 24 Timer 100 Image forming apparatus 200 Image forming apparatus 300 Image forming apparatus

Claims (7)

An image forming apparatus for forming an image on a recording material,
Detection means for detecting the temperature and humidity inside the apparatus;
An air flow generating means for introducing outside air into the apparatus;
Control means for controlling the airflow generation means based on the temperature and humidity inside the device and the temporal change in temperature;
An image forming apparatus comprising: The control means includes
Based on the temperature and humidity inside the device detected every predetermined time, the air flow generation means is controlled so that the outside air introduced into the device does not dew,
The image forming apparatus according to claim 1. The control means includes
Controlling the air flow generating means based on the temperature and humidity inside the apparatus first detected when the image forming apparatus is activated;
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The control means includes
Controlling the air flow generation means based on the absolute moisture content inside the apparatus determined from the change over time;
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The detection means includes
It is a conductive member whose electrical resistance value changes with temperature and humidity.
The control means includes
Obtaining a temperature and humidity inside the device from a current flowing through the conductive member or a voltage of the conductive member when a bias is applied to the conductive member;
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The conductive member is
Charging means for charging the image carrier,
The image forming apparatus according to claim 5. The conductive member is
Transfer means for transferring a developer image formed on an image carrier to a recording material,
The image forming apparatus according to claim 5.

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