JP2008181030A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that is made to suppress the degradation of functions for removing hazardous materials by a filter. <P>SOLUTION: The apparatus includes an image forming unit for forming an image of toner on a recording medium; a case including the image forming unit; an exhaust port arranged in the case for exhausting air, in the case to the outside thereof; a fan for sending air from a predetermined point of the image forming unit to the exhaust port; the filter where the air sent to the exhaust port passes prior to discharge; a detector for directly or indirectly detecting the moistened condition of the filter; and a drying means for drying the filter, when the moistened condition detected by the detector exceeds a predetermined extent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus having an image forming unit that forms a toner image on a recording medium.

  2. Description of the Related Art Conventionally, there is known an image forming apparatus that forms an image on a recording medium by transferring the formed toner image onto a recording sheet and fixing the toner image on the recording medium by a heat fixing device.

  Such an image forming apparatus is provided with a fan for discharging heat generated from the heat fixing device to the outside of the apparatus through an exhaust port provided in a part of the apparatus casing.

  However, it is known that harmful substances such as ozone and volatile organic compounds (hereinafter referred to as VOC) are generated from the heat fixing device.

  For this reason, an image forming apparatus equipped with a heat fixing device absorbs these harmful substances from hot air in front of the exhaust port so that these harmful substances are not discharged outside the apparatus together with hot air. Some have a filter.

  By the way, among these harmful substances, ozone is known to be inactivated by contact with moisture.

  Therefore, a proposal has been made to inactivate this ozone by utilizing the water contained in the recording paper and discharged as water vapor at the time of fixing by a heat fixing device (see Patent Document 1).

This proposal is based on the fact that hot air containing water vapor and ozone around the fuser moves in the duct provided between the fuser and the filter while moving from the fuser side to the filter side. This is intended to reduce the amount of ozone reaching the filter by promoting the reaction with.
JP-A-3-58063

  However, in the above proposal, since moisture adheres to the adsorption surface of the filter, the amount of ozone reaching the filter can be reduced, but the performance of the filter itself that adsorbs or decomposes harmful substances such as ozone and VOC. Since this deteriorates, the overall ability of the filter to remove harmful substances from the air may be reduced.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an image forming apparatus in which a reduction in the function of removing harmful substances of a filter is suppressed.

In order to achieve the above object, an image forming apparatus of the present invention comprises:
An image forming unit for forming a toner image on a recording medium;
A housing containing the image forming unit;
An exhaust port provided in the case for exhausting air inside the case to the outside of the case;
A fan that sends air from a predetermined portion of the image forming unit to the exhaust port;
A filter through which air sent to the exhaust port passes before discharge;
A detector that directly or indirectly detects the wetness of the filter;
And a drying means for drying the filter when the wetness detected by the detector exceeds a predetermined level.

  In the image forming apparatus of the present invention, when the wetness exceeds a predetermined level, means for drying the filter is taken, so that water adhering to the adsorption surface of the filter can be removed. Therefore, according to the image forming apparatus of the present invention, it is possible to suppress a decrease in performance of the filter for removing harmful substances.

  Here, it is preferable that the detector of the image forming apparatus of the present invention indirectly detects the wetness of the filter by detecting the humidity in the air.

  As described above, when the detector detects the humidity in the air indirectly by detecting the humidity in the air, it is conventionally provided in the apparatus for a purpose different from the detection of the filter wetness. The existing humidity sensor can be used.

  Furthermore, the detector detects the humidity in the air to indirectly detect the wetness of the filter, and estimates the current wetness using the current humidity and the past humidity. Is also a preferred embodiment.

  In this way, if the current wetness is estimated using the current humidity and the past humidity, the wetness of the filter can be detected more accurately.

Further, the image forming unit of the image forming apparatus of the present invention has a heat fixing device for fixing the image on the recording medium by heating,
It is preferable that the drying unit is configured to dry the filter using heat generated by the heating and fixing device when the wetness detected by the detector exceeds a predetermined level.

  As described above, it is convenient to use a heat generated by the heat fixing device to dry the filter because it is not necessary to provide a heat generating device for drying the filter.

  Furthermore, it is also a preferable aspect that the filter is dried using air heated by heat generated by the heat fixing device.

  Thus, if the filter is dried using the air heated by the heat generated by the heat fixing device, a mechanism for drying the filter can be easily realized.

Here, the image forming unit of the image forming apparatus of the present invention has a heat fixing device that fixes the image on the recording medium by heating,
The drying means increases the amount of heat generated by the heat fixing device when the wetness detected by the detector exceeds a predetermined level, and the heat is generated by the heat fixing device, and the filter is It is also a preferred embodiment that it is dried.

  Since the temperature of the heat fixing device is set to be optimal for image fixing, if the amount of heat from the heat fixing device is consumed for filter drying, the temperature of the heat fixing device becomes unstable. Adversely affects the establishment of Thus, if the heat generation amount of the heat fixing device is increased when the filter is dried in this way, it is possible to avoid adversely affecting image fixing.

Further, the image forming unit of the image forming apparatus of the present invention has a heat fixing device for fixing the image on the recording medium by heating,
The fan sends air from the heat fixing device to the exhaust port,
It is also a preferred aspect that the drying means dries the filter by increasing the rotational speed of the fan when the wetness detected by the detector exceeds a predetermined level.

  As described above, when the rotational speed of the fan is increased when the filter is dried, the filter can be quickly dried.

Here, the image forming unit of the image forming apparatus of the present invention has a heat fixing device that fixes the image on the recording medium by heating,
The fan sends air from the heat fixing device to the exhaust port,
When the drying unit is turned on by the image forming apparatus and the wetness detected by the detector exceeds a predetermined level, the image forming unit starts image formation by a predetermined amount. It is preferable that the filter is dried by prohibiting the period.

  When the power of the image forming apparatus is turned on, if the wetness detected by the detector exceeds a predetermined level, the start of image formation by the image forming unit is prohibited in this way for a predetermined period. Thus, it is possible to perform filter drying using the temperature rise inside the apparatus over time.

Further, the image forming unit of the image forming apparatus of the present invention includes a holding body that holds an image, a charger that charges the surface of the holding body, and a latent image that forms an electrostatic latent image on the surface of the charged holding body. An image forming device, a developing device for developing the electrostatic latent image with toner to form a developed image, a transfer device for transferring the developed image onto the recording medium, and heating the developed image on the recording medium. And a heat fixing device for fixing by
The fan sends air from both the charger and the heat fixing device to the exhaust port,
The filter passes both air sent from the charger and air sent from the heating and fixing device.
In the case where the wetness detected by the detector exceeds a predetermined level, the drying means promotes the drying effect of the filter by the air sent from the heat fixing device by the fan. It is also a preferred embodiment that the filter is dried.

  In this way, if both the air sent from the charger and the air sent from the heat fixing device pass through the filter, harmful substances generated from the charger are also actively removed by the filter. can do.

  According to the image forming apparatus of the present invention, it is possible to suppress a decrease in the function of the filter for removing harmful substances.

  Hereinafter, embodiments of the image forming apparatus of the present invention will be described.

  FIG. 1 is a diagram illustrating a first embodiment of an image forming apparatus according to the present invention.

  A printer 1 of the present embodiment shown in FIG. 1 is a monochrome image dedicated machine having an image forming unit 2 that forms an image on a recording medium by fixing a toner image on the recording medium. Includes an image carrier 21 that holds an image, a corotron 22 that charges the surface of the image carrier, an exposure unit 23 that forms an electrostatic latent image on the surface of the image carrier 21 charged by the corotron 22, The electrostatic latent image is developed with a toner held on the surface of the developing roll 241 to form a developed image, a transfer roll 25 that transfers the developed image onto a recording medium, and the developed image is A fixing device 26 for fixing the recording medium by heating is a constituent element. The fixing device 26 includes a heating roll 261 and a pressure roll 262.

  In addition to the image forming unit 2, the printer 1 according to the present embodiment includes a housing 10 including the image forming unit 2 and provided with an exhaust port 10 a for exhausting internal air to the outside. The duct 3 extending from the exhaust port 10a to the corotron 22 and the fixing device 26, the fan 4 for sending the air around the corotron 22 and the periphery of the fixing device 26 to the exhaust port 10a, and the air sent to the exhaust port 10a The filter 5 which passes before discharging | emitting from the discharge port 10a and the environmental sensor 6 for detecting the temperature and humidity in a housing | casing are provided.

  Further, the printer 1 of the present embodiment includes a paper feed cassette 7 that stores recording paper, and a transport device 8 that transports the recording paper drawn from the paper feed cassette 7 along the transport path 9. In the printer 1, a plurality of paper feed cassettes 7 can be loaded at predetermined positions below the housing 10, and a transport roll 91 is provided along the transport path 9. Further, the printer 1 is provided with an operation panel that is operated when designating a paper feed cassette 7 in which a desired recording paper is accommodated when a plurality of paper feeds 7 are loaded. Further, the printer 1 is provided with a CPU 10 that controls each part of the operation of the printer 1.

  The fan 4 is disposed inside the duct 3 and mainly sends air around the corotron 22 and air around the fixing unit 26 to the exhaust port 10a. Both the air around the corotron 22 containing ozone and the air around the fixing device 26 containing ozone and VOC generated from the fixing device 26 pass through the filter 5. It becomes.

  The environment sensor 6 transmits a signal representing the temperature and humidity in the housing to the CPU 100.

Here, the flow of image formation in the printer 1 will be briefly described with reference to FIG.

  First, the user selects and designates the paper cassette 7 containing the desired type of recording paper, the number of sheets, and the like from the plurality of paper cassettes 7 loaded, and presses a start button (not shown). To instruct the start of image formation. As a result, the selected paper feed cassette 7 and the transport device 8 cooperate to transport the recording paper stored in the selected paper feed cassette 7 toward the image forming unit 2.

  In the image forming unit 2, a toner image is formed in accordance with the conveyance of the recording paper, and this toner image is transferred onto the recording paper by the transfer roll 25. Thereafter, the toner image transferred onto the recording paper is heated and pressurized by the fixing device 26 and fixed onto the recording paper, and the recording paper with the toner image fixed thereon is discharged onto the upper surface 101 of the housing 10. .

  In the printer 1, power supply to the heater in the heating roll is started at the same time as the power is turned on so that the temperature of the heating roll 261 becomes a temperature necessary for melting the toner image. Rotation at the number of rotations is instructed.

  Along with the image forming operation described above, ozone is generated from the corotron 22 and harmful substances such as ozone and VOC are generated from the fixing device 26. These harmful substances together with air are shown in FIG. 3 moves to the exhaust port side, and is adsorbed by the filter 5 provided in front of the exhaust port 10a.

  Here, in the printer 1 of the present embodiment, whenever the power-off is instructed, the humidity data at that time is stored in a memory (not shown), and the humidity information obtained at that time every time the power is turned on. And the wetness of the filter 5 is estimated based on the humidity information obtained when the power was turned off last time. Thereafter, it is determined whether or not the estimated wetness of the filter 5 exceeds a preset degree. If it is determined that the filter 5 has exceeded, the image forming operation is prohibited unless the filter 5 is dried to some extent. It has become so. This is because if the filter 5 is too wet, there is a high possibility that moisture is attached to the adsorption surface of the filter 5, and if so, the function of the filter 5 to remove harmful substances is reduced, and image formation is accompanied. This is because harmful substances generated from the corotron 22 and the fixing device are discharged out of the housing.

  The drying of the filter 5 in the printer 1 is performed by setting the heat generation amount of the fixing unit 26 to be larger than the heat generation amount at the time of image formation and the rotational speed of the fan 5 to be larger than the rotation speed at the time of image formation. .

  Hereinafter, filter drying in the printer 1 will be described in detail.

  FIG. 2 is a flowchart of a routine program executed in the printer of this embodiment.

  The program configured by the flowchart shown in FIG. 2 is stored in a memory (not shown), and is executed when the printer 1 is turned on.

  In step S1 shown in FIG. 2, the current humidity is detected by the environmental sensor 6, and in step S2, the humidity data detected and stored in the memory when the previous power-off is instructed is read. In step S3, the wetness of the filter 5 is estimated from the humidity data representing the current humidity and the humidity data stored in the memory. This estimation is based on these present and past humidity data, a reference humidity value that serves as a reference is calculated, and a table representing the relationship between the humidity value and the water content of the filter 5 that has been experimentally obtained in advance is shown below. This is done by determining the moisture content relative to the reference humidity value as the wetness. In step S4, it is determined whether or not the estimated wetness of the filter 5 is equal to or higher than a predetermined level, that is, equal to or higher than a predetermined water content. The predetermined moisture content is set to a moisture content that is also experimentally determined in advance, and from which the absorptivity of harmful substances rapidly decreases from the relationship between the moisture content and the adsorptivity of harmful substances. If it is determined in step S4 that the filter 5 is wet above a predetermined level, the process proceeds to step S5 to instruct prohibition of image formation. Then, it progresses to step S6, the fan 4 is rotated by the maximum rotation speed, and the emitted-heat amount of the heating roll 261 is raised to the maximum in step S7. In step S8, it is determined whether a predetermined time set in advance has elapsed. If it is determined in step S8 that the predetermined time has not elapsed, step S8 is repeated. If it is determined in step S8 that the predetermined time has elapsed, the process returns to step S1. On the other hand, if it is determined in step S4 that the wetness of the filter 5 is not equal to or higher than the predetermined level, the process proceeds to step S9, where image formation is permitted. Return to normal value. In step S11, it is determined whether or not there is an instruction to turn off the power. If it is determined in step S11 that there is no instruction to turn off the power, step S11 is repeated. If it is determined that there is an instruction to turn off the power, the process proceeds to step S12, and the humidity data at that time is stored in the memory. Thereafter, this routine is terminated.

  As described above, in the printer 1 of the present embodiment, when the wetness exceeds a predetermined level, the filter 5 is dried, so that moisture is prevented from adhering to the adsorption surface of the filter 5. . Thereby, according to the printer 1 of this embodiment, the fall of the performance which removes a harmful substance of the filter 5 can be suppressed.

  Further, in the printer 1 of the present embodiment, drying of the filter 5 is realized by simple means such as guiding hot air generated from the fixing device 26 to the filter 5 through the duct 3. Further, in the printer 1 of the present embodiment, when the power of the printer 1 is turned on, image formation is prohibited when the wetness of the filter 5 is equal to or higher than a predetermined level. Therefore, image formation is performed until the filter 5 is dried. Occurrence of a situation where harmful substances are discharged outside the housing is prevented. In the above embodiment, an example of estimating the current wetness of the filter 5 from the humidity data when the printer 1 is turned on and the humidity data detected and stored when the printer was turned off the last time. However, the present invention may directly detect the wetness of the filter. Further, in order to dry the filter 5, the example in which the rotational speed of the fan 4 and the heat generation amount of the heating roll 261 are increased as compared with the image forming time has been described. However, the present invention only applies one of these. If the image forming operation is prohibited for a predetermined time, the present invention does not need to perform both. Furthermore, if the filter 5 has a means for drying it when it is moistened to a predetermined degree or more, the basic effect of the present invention is not reduced even if the image forming operation is not prohibited for a predetermined time. Absent.

  In the above embodiment, the case where both the air around the fixing device 26 and the air around the corotron 22 are guided to the filter 5 using the duct 3 has been described as an example. Alternatively, only the air around the fixing device 26 may reach the filter 5.

  Further, the case where the heat generated from the fixing device 26 is used for drying the filter 5 has been described as an example. However, the present invention is not limited to this, and a heat generating device only for drying the filter may be provided. Good.

1 is a diagram illustrating a first embodiment of an image forming apparatus according to the present invention. It is a flowchart of a routine program executed in the printer of the present embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer 10 Housing | casing 11 Operation panel 2 Image formation part 21 Image holding body 22 Corotron 23 Exposure device 24 Developing device 25 Transfer roll 26 Fixing device 3 Duct 4 Fan 5 Filter 6 Environment sensor 7 Paper feed cassette 8 Conveyance device 9 Conveyance path

Claims (9)

An image forming unit for forming a toner image on a recording medium;
A housing containing the image forming unit;
An exhaust port provided in the housing for exhausting air inside the housing to the outside of the housing;
A fan that sends air from a predetermined location of the image forming unit to the exhaust port;
A filter through which air sent to the exhaust port passes before being discharged;
A detector for directly or indirectly detecting the wetness of the filter;
An image forming apparatus comprising: a drying unit that dries the filter when the wetness detected by the detector exceeds a predetermined level.   The image forming apparatus according to claim 1, wherein the detector indirectly detects the wetness of the filter by detecting humidity in the air.   The detector indirectly detects the wetness of the filter by detecting the humidity in the air, and estimates the current wetness using the current humidity and the past humidity. The image forming apparatus according to claim 1. The image forming unit has a heat fixing device for fixing the image on the recording medium by heating;
The drying unit is configured to dry the filter using heat generated by the heating and fixing device when the wetness detected by the detector exceeds a predetermined level. The image forming apparatus according to claim 1. The image forming unit has a heat fixing device for fixing the image on the recording medium by heating;
The drying means increases the amount of heat generated by the heating and fixing device when the wetness detected by the detector exceeds a predetermined level, and uses the heat generated by the heating and fixing device to filter the filter. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is dried. The image forming unit has a heat fixing device for fixing the image on the recording medium by heating;
The drying means dries the filter using air heated by heat generated by the heating and fixing device when the wetness detected by the detector exceeds a predetermined level. The image forming apparatus according to claim 1. The image forming unit has a heat fixing device for fixing the image on the recording medium by heating;
The fan sends air from the heat fixing device to the exhaust port;
2. The filter according to claim 1, wherein the drying means dries the filter by increasing the rotational speed of the fan when the wetness detected by the detector exceeds a predetermined level. Image forming apparatus. The image forming unit has a heat fixing device for fixing the image on the recording medium by heating;
The fan sends air from the heat fixing device to the exhaust port;
When the image forming apparatus is powered on, the drying unit prohibits the image forming unit from starting image formation for a predetermined period if the wetness detected by the detector exceeds a predetermined level. The image forming apparatus according to claim 1, wherein the filter is dried. The image forming unit includes: a holding body that holds an image; a charger that charges the surface of the holding body; a latent image forming device that forms an electrostatic latent image on the surface of the charged holding body; A developing unit for developing the image with toner to form a developed image; a transfer unit for transferring the developed image onto the recording medium; and a heat fixing unit for fixing the developed image on the recording medium by heating. Is,
The fan sends air from both the charger and the heat fixing device to the exhaust port,
The filter passes both air sent from the charger and air sent from the heat fixing device,
When the wetness detected by the detector exceeds a predetermined level, the drying means promotes the drying effect of the filter by the air sent from the heating and fixing device by the fan. 2. The image forming apparatus according to claim 1, wherein the filter is dried.

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