JP2006215308A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To extend the service life of a filter for collecting volatile organic compounds produced from resin components or the like used in an image forming apparatus by efficiently using the filter. <P>SOLUTION: The image forming apparatus 100 has a ventilating axial fan 54 for discharging air from its inside to its outside, and the filter 58 through which air current generated by the ventilating axial fan 54 passes. The filter 58 scavenges the volatile organic compound in the air. The apparatus has a storage device 151 for storing information on the number of recorded sheets of recording material. The quantity of the air passing through the filter 58 is controlled by the ventilating axial fan 54 based on the information stored in the storage device 151. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus using an electrophotographic method, and more particularly to an image forming apparatus having a function of collecting a volatile organic compound generated in the apparatus.

  2. Description of the Related Art Conventionally, as an image forming apparatus using an electrophotographic system, a plurality of image forming units are provided, toner images of different colors are formed in each image forming unit, and the same recording material carried and conveyed by a recording material carrier An image forming apparatus for forming a color image by sequentially superimposing and transferring the respective color toner images thereon, and transferring each color toner image by sequentially superimposing and transferring the color toner image onto the intermediate transfer member. Various proposals have been made for an image forming apparatus that forms a color image by batch-transferring toner images onto a recording material.

  A color image forming apparatus including a plurality of such image forming units is called a tandem type, and has a general color image forming apparatus configuration because the recording speed can be set high.

  However, in recent years, the printing speed of the above-described color image forming apparatus has been further increased, and heat generated from an electric unit such as a motor and a power source, a fixing device, etc., which is a heat generation source in the apparatus, has been developed. The total amount is increasing.

  For this purpose, the image forming apparatus is provided with an intake and exhaust fan and duct for cooling the inside of the apparatus. As the air flow inside the device by the intake and exhaust fans and ducts, the air taken from outside the device is sent to the above-mentioned heat sources (electrical units such as motors, power supplies, etc.) and the heat is taken away. Air is exhausted outside the equipment.

  Further, in the above-described color image forming apparatus, when recording is performed on both sides of the recording material, the recording material on which one side is recorded again passes through a high-temperature fixing device and has heat. It passes through the above-described image forming unit. As a result, the temperature of the image forming unit is raised, but air is also sent to the image forming unit using the fan and duct described above, and the air deprived of heat is exhausted outside the apparatus in the same manner as described above. I have to.

Japanese Patent Laid-Open No. 2003-186324

  As described above, when air is exhausted for cooling the inside of the apparatus, substances generated in the apparatus are also exhausted. In recent years, the discharge amount of substances generated in the apparatus has been regulated from an environmental standpoint.

  Japanese Patent Application Laid-Open No. 2003-186324 (Patent Document 1) discloses an image forming apparatus in which a fixing unit as a heating unit is provided with a member that adsorbs formaldehyde generated from toner or oil. Some devices have a dust collection filter attached to the exhaust port so that toner particles are not discharged outside the device.

  As the discharge amount of substances generated in the apparatus is regulated in this way, a trace amount of volatile organic compounds generated from resin parts used in the image forming apparatus are also concerned. It is coming. Specifically, there are standards such as the BAM standard, the UL standard, and the TUV standard that regulate the emission amount of the volatile organic compounds described above, and the necessity of satisfying these standards has arisen also in the image forming apparatus.

  Conventionally, a lot of resin has been used for the components constituting the image forming apparatus as described above. The reason why the resin is used for the parts constituting the image forming apparatus is that it has a higher degree of freedom in shape and lighter than metal. Actually, resin such as ABS, PS, PC + ABS, PPE, and POM is used for about 50% to 80% of the total number of parts in the apparatus, such as an exterior cover, a sheet guide, and a gear.

  A part of the volatile organic compounds whose emission amount is regulated in the aforementioned standard is generated from resin parts made of ABS, PS, PC + ABS, PPE, etc. used in the image forming apparatus. These resin parts are resin components by being exposed to heat generated by the drive motor, power supply, fixing device, or temperature rise in the apparatus due to the passing of heated recording material during double-sided recording. Chemical substances such as styrene (boiling point: 145.2 ° C.) and benzene (boiling point: 80.1 ° C.) reach the boiling point, become gas and are exhausted outside the device through the fan and duct provided in the device.

  As described above, in recent years, the speed of image forming apparatuses and the standardization of double-sided recording have progressed, the amount of heat generated in the apparatus has increased, and the resin parts disposed in the apparatus have been exposed to more heat than ever. . As a result, the amount of volatile organic compounds generated from the resin parts is also an amount that cannot be ignored.

  Further, in the image forming apparatus, the recording material passing through the fixing device to heat and fix the toner image is heated to about 150 to 200 degrees, and the components in the recording material are volatilized together with the moisture in the recording material. For example, in the case of a sheet of the recording material in which the surface of the paper is coated with a resin coating in order to increase glossiness, a volatile organic compound is generated from the coating agent of the sheet although the amount is small.

  In order to collect volatile organic compounds generated from these resin parts and recording materials, it is effective to use a collection filter containing activated carbon or the like as a main component. This type of filter collects volatile organic compounds by physically adsorbing gaseous substances in fine pores called pores. This collection filter collects a certain amount of volatile organic compounds contained in the exhaust air by an amount corresponding to the wind speed of the fan rotating at a constant speed.

  However, as the speed of the image forming apparatus as described above, standardization of double-sided recording, and networking are progressing, the number of output sheets of recording material tends to increase, and further, the number of output sheets and the number of print jobs Etc. are various. For this reason, when a large number of sheets are output continuously, or when a job for outputting a large number of sheets is performed continuously, the temperature inside the image forming apparatus due to the passing of the recording material heated through the fixing device However, the amount of the volatile organic compound generated from the resin component exposed to heat due to the temperature rise in the apparatus is not constant.

  For this reason, when the volatile organic compounds generated from many resin parts used in the image forming apparatus exceed the collection amount of the filter by the fan rotating at the constant speed, the various standards described above are prescribed. The amount of volatile organic compounds exceeding the value may be exhausted outside the apparatus.

  On the other hand, even when the amount of volatile organic compounds generated from many resin parts used in the image forming apparatus does not exceed the amount collected by the filter, the fan rotates at a constant speed. Since the collection amount of the filter is constant, a constant amount of volatile organic compounds in the exhaust air is always collected. That is, even if the number of output sheets of the recording material is small and the amount of volatile organic compounds generated by the temperature rise in the apparatus is below the specified value, the volatile organic compounds in the air exhausted from the apparatus to the outside of the apparatus Will be collected more than necessary. By collecting more volatile organic compounds in this way, the period during which the filter can be collected decreases, and as a result, the lifetime of the filter that collects the volatile organic compounds is shortened. There is a problem that the volatile organic compound cannot be efficiently collected by the filter.

  Therefore, an object of the present invention is to discharge volatile organic compounds generated from resin parts in the image forming apparatus, which fluctuate according to the number of output sheets of recording material, to the outside of the apparatus in an amount exceeding the prescribed values of various standards. It is to prevent that.

  Another object of the present invention is to enable efficient collection of volatile organic compounds by the filter even when the amount of volatile organic compounds generated from within the image forming apparatus increases or decreases, Prolonging the life of the filter.

  A typical configuration of the present invention for achieving the above object has an exhaust means for exhausting air from the inside of the apparatus to the outside of the apparatus, and a filter through which an air flow generated by the exhaust means passes, In the image forming apparatus that collects volatile organic compounds in the air, the filter has storage means for storing information relating to the number of recording sheets of recording material, and based on the information stored in the storage means, the exhaust means The amount of air passing through the filter is controlled.

  As described above, according to the present invention, the volatile organic compound generated from the image forming apparatus is discharged out of the apparatus in an amount exceeding the specified values of various standards, regardless of the number of output recording materials. Can be prevented. Further, the volatile organic compound can be efficiently collected by the filter, and the life of the filter can be extended.

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

[First Embodiment]
The image forming apparatus according to the first embodiment of the present invention will be described in detail with reference to FIGS.

  First, the overall configuration of the image forming apparatus will be outlined with reference to FIG. FIG. 1 is a longitudinal sectional view showing the overall configuration of a full-color laser beam printer 100 which is an aspect of the image forming apparatus.

  An image forming apparatus 100 shown in the figure includes four photosensitive drums 1a, 1b, 1c, and 1d arranged in parallel in the vertical direction. A photosensitive drum 1 (1a, 1b, 1c, 1d) as an image carrier is rotationally driven counterclockwise in the drawing by a driving means (not shown). A charging device 2 (2a, 2b, 2c, 2d) for uniformly charging the surface of the photosensitive drum 1 in order according to the rotation direction, and a toner attached to the electrostatic latent image around the photosensitive drum 1 A developing device 4 (4a, 4b, 4c, 4d) for developing as an image, a cleaning device 6 (6a, 6b, 6c, 6d) for removing transfer residual toner remaining on the surface of the photosensitive drum 1 after transfer, and the like are provided. Has been. 3 (3 a, 3 b, 3 c, 3 d) is a scanner unit 5 that forms an electrostatic latent image on the photosensitive drum 1 by irradiating a laser beam between the charging device 2 and the developing device 4 based on image information. This is an electrostatic transfer unit as a transfer unit that faces a plurality of photosensitive drums 1a, 1b, 1c, and 1d and transfers a toner image on the photosensitive drum 1 to a sheet S as a recording material.

  Here, the photosensitive drum 1 and the charging device 2, the developing device 4, and the cleaning device 6 as process means that act on the photosensitive drum 1 are integrally formed into a cartridge that is detachable from the image forming apparatus main body 100. Process cartridges 7 (7a, 7b, 7c, 7d) are formed. The process cartridge 7 and the electrostatic transfer unit 5 constitute an image forming unit that forms an image on a sheet.

  Each developing device 4a, 4b, 4c, 4d in each process cartridge 7 is composed of a developing unit that stores toner of each color of yellow, magenta, cyan, and black, respectively. There is a toner container for storing toner in the developing device, and the LED light is transmitted through the toner container to detect the transmission time and to detect the remaining amount of toner.

  The electrostatic transfer unit 5 has an electrostatic transfer belt 11 as a sheet carrier for carrying and conveying a sheet. The electrostatic transfer belt 11 is supported in the vertical direction by four rollers including a driving roller 13, driven rollers 14a and 14b, and a tension roller 15. The sheet S is circulated so as to contact the body drum 1. Further, transfer rollers 12 (12a, 12b, 12c, 12d) are arranged in parallel at positions facing the inside of the electrostatic transfer belt 11 and facing the four photosensitive drums 1a, 1b, 1c, 1d. As a result, the sheet S is conveyed to each transfer position by the electrostatic transfer belt 11, and the toner image on each photosensitive drum 1 is transferred by each transfer roller 12.

  The feeding unit 16 feeds the sheet S to the image forming unit, and a plurality of sheets S are stored in the cassette 17. At the time of image formation, the feeding roller 18 (half-moon roller) feeds the uppermost sheet S on the cassette 17, the leading edge of the sheet S abuts against the registration roller pair 19, temporarily stops, forms a loop, and then the electrostatic transfer belt 11. The rotation and the image writing position are synchronized, and the sheet is fed to the electrostatic transfer belt 11 by the registration roller pair 19.

  The fixing unit 20 as a fixing unit fixes the toner images of a plurality of colors transferred to the sheet S, and includes a rotating heating roller 21a and a pressure roller that presses and applies heat and pressure to the sheet S. 21b. Downstream of this, there is a pair of discharge rollers 23 for discharging the sheet S out of the apparatus main body.

  In addition, a discharge sensor (not shown) is disposed between the fixing roller pair 21 and the discharge roller pair 23 to check whether the sheet S has been reliably discharged out of the apparatus or is not wound around the fixing roller pair 21. Monitoring.

  In addition, a double-sided path used when image recording is performed on both sides of the sheet S is formed on the back surface of the electrostatic transfer belt unit 5. A switching flapper 24 for switching whether to discharge a sheet to the discharge unit 31 or to guide the sheet to the duplex path, and a sheet guided to the duplex path by the switching flapper 24 are switched back to the entrance of the duplex path. A pair of possible transport rollers 25 and a transport roller pair 26 for transporting the switchback transported sheet into the double-sided path are arranged to transport the sheet S downward in the figure. A U-turn path 30 is provided at the lowest point of the double-sided path to change the sheet conveyance direction, and the sheet S guided to the U-turn path 30 is re-fed to the registration roller pair 19.

  As an image forming operation, the process cartridges 7a, 7b, 7c, and 7d are sequentially driven in accordance with the recording timing, and the photosensitive drums 1a, 1b, 1c, and 1d are rotated counterclockwise in accordance with the drive. Driven. Then, the scanner units 3 corresponding to the respective process cartridges 7 are sequentially driven. By this driving, the charging roller 2 imparts a uniform charge to the circumferential surface of the photosensitive drum 1, and the scanner unit 3 exposes the circumferential surface of the photosensitive drum 1 according to the image signal to perform photosensitive drum 1. An electrostatic latent image is formed on the peripheral surface. The developing roller in the developing device 4 transfers (transfers) the toner to the electrostatic latent image and forms (develops) the toner image on the circumferential surface of the photosensitive drum 1.

  At the timing when the leading edge of the toner image on the circumferential surface of the photosensitive drum 1 that is the most upstream is rotated and conveyed to a point facing the electrostatic transfer belt 11, the recording start position of the sheet S coincides with that point. Then, the registration roller pair 19 starts to rotate and feeds the sheet S to the electrostatic transfer belt 11.

  The sheet S is pressed against the outer periphery of the electrostatic transfer belt 11 so as to be sandwiched between the electrostatic adsorption roller 22 and the electrostatic transfer belt 11, and a voltage is applied between the electrostatic transfer belt 11 and the electrostatic adsorption roller 22. By doing so, the sheet S is configured to be electrostatically attracted to the outer periphery of the electrostatic transfer belt 11. As a result, the sheet S is stably adsorbed to the electrostatic transfer belt 11 and conveyed to the most downstream transfer unit.

  While being conveyed in this way, the toner images on the photosensitive drums 1 are sequentially transferred to the sheets S by an electric field formed between the photosensitive drums 1 and the transfer rollers 12.

  The sheet S to which the four color toner images are transferred is separated from the electrostatic transfer belt 11 by the curvature of the belt driving roller 13 and is carried into the fixing unit 20. After the toner image is thermally fixed by the fixing unit 20, the sheet S is discharged out of the apparatus by the discharge roller pair 23 with the image surface facing down to the discharge unit 31.

  The operation of double-sided recording will be described. When the printer main body receives the duplex recording signal, the switching flapper 24 guides the sheet S to the conveyance roller pair 25 and detects that the sheet S has passed through the fixing roller pair 21 by the discharge sensor. Based on the detection signal, the conveying roller pair 25 rotates in the reverse direction and guides the sheet S to the conveying roller pair 26. The sheet S that has entered the double-sided path by the conveying roller pair 26 is conveyed by the conveying roller pair 28 and 29 to the registration roller pair 19 through the U-turn path 30. Thereafter, the back surface recording is completed in the same image forming process as the front surface recording, and the sheet S on which the images are recorded on the front and back surfaces is discharged to the discharge unit 31.

  The image forming apparatus 100 uses resin parts in many other locations such as an exterior cover, a sheet guide, and a user access unit. As materials for the resin parts, ABS (acrylonitrile / butadiene / styrene), PS (polystyrene), PC (polycarbonate), POM (polyacetal), and the like are properly used according to functions required for each part.

  Next, the airflow configuration in the image forming apparatus 100 will be described with reference to FIG. 2A and 2B are explanatory views showing an airflow configuration of the image forming apparatus, in which FIG. 2A is a top view of the image forming apparatus 100 and FIG. 2B is a perspective view of a filter.

  As shown in FIG. 2, an intake axial fan 51 is disposed on the left side surface portion of the image forming apparatus main body 100. The intake axial fan 51 (80 mm square axial fan in this embodiment) is directly fixed to the left cover 52 with screws. The left cover 52 that is a part of the exterior cover that forms the exterior of the apparatus is formed of a resin such as ABS, and a louver 53 is integrally formed in the vicinity of the intake axial flow fan 51. The intake axial flow fan 51 rotates in a direction to take outside air into the apparatus main body. In order to suppress a temperature rise in the apparatus, air (such as an image forming unit or a fixing unit 20) is air ( Air).

  In addition, an exhaust axial flow fan 54 that constitutes an exhaust unit is disposed in the right rear portion of the image forming apparatus main body 100. The exhaust axial flow fan 54 (80 mm square axial flow fan in the present embodiment) rotates in a direction to discharge the air inside the apparatus to the outside of the apparatus, and the apparatus temperature raising unit such as the image forming unit or the fixing unit 20. Air (air), which has been deprived of heat by blowing on the air, is exhausted toward the outside of the device.

  The exhaust axial flow fan 54 is held by a fan holder 55 in which a duct portion is integrally formed. The fan holder 55 is formed of a resin such as ABS, and the exhaust axial flow fan 54 is fixed by a snap fit (not shown).

  One end of the fan holder 55 is engaged with a louver 57 that is formed integrally with a rear cover 56 that is a part of the exterior cover that forms the exterior of the apparatus. The other end of the fan holder 55 is disposed so as to face the image forming unit or the fixing unit 20 that is a temperature raising unit in the image forming apparatus 100. As a result, the axial fans 51 and 54 generate an air flow (air flow) in the direction of the arrow in FIG. 2A, blow the air taken from the outside of the apparatus into the apparatus to the temperature raising part in the apparatus, and The air is effectively exhausted outside the equipment.

  The fan holder 55 holds the exhaust axial fan 54 and holds a filter 58 as a collecting member at a position close to the exhaust axial fan 54. The filter 58 is fixed by a snap fit (not shown) formed in the fan holder 55. The filter 58 according to the present embodiment is an activated carbon filter through which an air flow generated by the exhaust means passes and which contains activated carbon to collect volatile organic compounds in the air.

  The filter 58 is arranged at a position away from the exhaust axial flow fan 54 by a predetermined distance (about 20 mm in this embodiment) so as not to generate wind noise of the exhaust axial flow fan 54. In general, the axial flow fan has a characteristic that the wind speed on the intake side is substantially uniform regardless of the position, and the wind speed varies depending on the position because the exhaust side exhibits radial wind power. Therefore, in the present embodiment, the filter 58 is disposed on the upstream side of the air flow with respect to the exhaust axial flow fan 54 so as to allow air to uniformly pass through the filter 58.

  The filter 58 has activated carbon as its material, has fine pores on its surface, and physically adsorbs volatile organic compounds such as styrene and benzene in the air passing through the filter 58. The ones that can be collected are used.

  The filter 58 has the same size as the exhaust axial flow fan 54 (80 mm square size in this embodiment). The thickness of the filter 58 is appropriately determined depending on the required lifetime and the amount of volatile organic compound that needs to be collected, and is set to 20 mm in this embodiment.

  The filter 58 has activated carbon as its material, has fine pores on its surface, and physically adsorbs volatile organic compounds such as styrene and benzene in the air passing through the filter 58. The ones that can be collected are used.

  Further, the filter 58 has a honeycomb structure as shown in FIG. 2B, and air can be evenly passed through the filter 58 without disturbing the air flow in the direction of the arrow in the figure. . In addition, since the filter 58 can maximize the surface area in contact with air, the performance of collecting volatile organic compounds in the air is improved.

  Next, changes in the internal temperature of the image forming apparatus will be described with reference to FIG.

  First, a description will be given of changes in the temperature in the apparatus when continuous printing is performed. FIG. 3A is an explanatory diagram showing changes in the internal temperature when the image forming apparatus 100 performs continuous printing on a predetermined number of sheets. A curve indicated by a solid line in FIG. 3A shows the temperature change of the atmosphere in the vicinity of the fixing device 20 when five sheets are continuously printed.

  As shown in FIG. 3A, when the printing operation starts, heating of the fixing device 20 starts, and the temperature in the apparatus rises. When the fifth sheet passes through the fixing device 20, the fixing device 20 stops the heating temperature adjustment. When the heating temperature adjustment is stopped, the heat in the apparatus is discharged outside the apparatus by the airflow (airflow) generated by the intake axial fan 51 and the exhaust axial fan 54 described above. As a result, in the figure, the temperature in the apparatus gradually decreases from the time of the temperature peak value 61 at the time of continuous printing of five sheets.

  Moreover, the curve shown with the broken line in Fig.3 (a) shows the temperature change at the time of performing 10 continuous printing, and the curve shown with the dashed-two dotted line in Fig.3 (a) is 20 continuous. It shows the temperature change when printing.

  As shown in FIG. 3A, when the tenth sheet passes through the fixing device 20, the temperature inside the apparatus decreases. In this case, it can be seen that the temperature peak value 62 is larger than the peak value 61 when five sheets are continuously printed. Further, when the temperature change at the time of continuous printing of 20 sheets indicated by a two-dot chain line in FIG. 3A, the temperature peak value 63 is found to be higher than the peak values 61 and 62.

  Thus, it can be seen that when continuous printing is performed, the peak value of the internal temperature of the apparatus increases in accordance with the number of continuous printed sheets.

  Next, a description will be given of changes in the temperature in the apparatus when recording jobs for printing an arbitrary number of sheets are continuously performed. FIG. 3B is an explanatory diagram showing a change in the internal temperature when the image forming apparatus 100 continuously performs a recording job for performing continuous printing on an arbitrary number of sheets at a predetermined time. Here, a case where a recording job for continuously printing 10 sheets is performed three times will be described as an example.

  FIG. 3B shows a temperature change when ten continuous prints are repeated three times at a certain time. As shown in FIG. 3B, when the ten continuous prints that are the first recording job are completed, the temperature is decreased from the temperature peak value 64 at the time of the first recording job. If the second recording job (10 sheets continuous printing) is started after a predetermined time t1 before the temperature reaches the steady temperature 65, the temperature rises again from the temperature 66 in the middle of the decrease. The third recording job is performed in the same manner. When a recording job for performing continuous printing in this manner is continuously repeated within a short time, the temperature inside the apparatus continues to rise as shown in FIG.

  Thus, it can be seen that the temperature inside the apparatus rises if the recording job is frequently performed within a certain time.

  As described above, it is known that the resin used in the apparatus generates a volatile organic compound, and the generation amount is promoted when a certain temperature is reached. That is, it is known that the temperature in the apparatus increases due to continuous printing and high-density print jobs, and as a result, the amount of volatile organic compounds generated increases.

  The sheet to be recorded is heated to about 120 to 180 ° C. by the fixing device 20. At that time, the components in the sheet are also gasified from the sheet. For example, there is a special sheet in which the surface of paper is coated to improve glossiness. When the special sheet passes through the fixing device 20, the coating component is generated as a volatile organic compound although the amount is small. In addition, sheets other than paper have been used. A resin film is representative, and as described above, when passing through the fixing device 20, a small amount of a component in the resin is generated as a volatile organic compound.

  Therefore, the image forming apparatus according to the present embodiment has storage means for storing information relating to the number of printed sheets, and passes through the filter 58 by the exhaust axial flow fan 54 based on the information stored in the storage means. The amount of air to be controlled is controlled. The image forming apparatus according to the present embodiment includes a storage device (first storage unit) 151 that temporarily stores recording data to be output to the sheet as the storage unit (see FIG. 1). Based on the information stored in the storage device 151, the rotational speed of the exhaust axial flow fan 54 is controlled. The exhaust axial flow fan 54 is controlled by a CPU 60 (see FIG. 1) as a control means for controlling each part of the entire image forming apparatus. Hereinafter, the variable control of the exhaust axial flow fan 54 according to the temperature change in the image forming apparatus based on the information related to the number of recorded sheets will be described.

  FIG. 4 shows the relationship between the air velocity passing through the filter 58 and the collection efficiency with which the filter 58 collects volatile organic compounds. The air wind speed is slowed or increased by controlling the rotational speed of the exhaust axial flow fan 54 based on the information stored in the storage device 151, specifically by decreasing or increasing the rotational speed of the fan. Become.

  As shown in FIG. 4, it is generally known that the slower the wind speed by the axial fan 54, the higher the collection efficiency of the volatile organic compound by the filter 58. Normally, the axial fan 54 arranged for suppressing the temperature rise in the apparatus is used at the maximum rotational speed (the chain line a in FIG. 4) so as to achieve the maximum wind speed of the fan. In the axial fan 54 rotated at the maximum rotation speed, the collection efficiency of the volatile organic compound by the filter 58 is lower than that at the rotation speed at which the wind speed is lower than that, and the volatilization by the filter 58 is reduced. The performance of collecting organic organic compounds has not been fully demonstrated.

  FIG. 4 shows the minimum speed of the exhaust axial flow fan 54 employed in the present embodiment by a one-dot chain line b. As can be seen from FIG. 4, the collection efficiency by the filter 58 at the minimum fan rotation speed is about twice as high as that of the axial fan 54 at the maximum rotation speed.

  Therefore, in this embodiment, as shown in FIG. 3, the wind speed by the exhaust axial flow fan 54 is changed according to the temperature rise of the apparatus main body, that is, the amount of volatile organic compounds generated from the resin parts and the recording material of the apparatus main body, The collection efficiency of the volatile organic compound by the filter 58 is optimized so that the volatile organic compound in the air exhausted outside the apparatus is less than the specified value and the life of the activated carbon filter 58 is extended. .

  The specific control will be described with reference to FIG. FIG. 5 shows the relationship between the apparatus internal temperature and the rotational speed of the exhaust axial flow fan 54 when 20 continuous print jobs are performed. The exhaust axial flow fan 54 employs a fan capable of two-stage control of the high speed rotation and the low speed rotation described above, and normally rotates at a high speed for cooling the inside of the apparatus.

  The image forming apparatus 100 obtains the number of sheets to be output continuously from the information stored in the storage device 151. When the number of sheets to be continuously output exceeds a predetermined number, the rotation of the fan 54 is performed so that the speed of the airflow generated by the exhaust axial flow fan 54 is reduced as compared with the case where the number is less than the predetermined number. Control the number.

  For example, when a print command for 20 sheets is received from the image forming apparatus 100, 20 print data are spooled (temporarily stored) in the storage device 151. When starting 20 continuous print jobs, the image forming apparatus 100 determines whether the number of sheets to be continuously output (20 sheets in this embodiment) exceeds a predetermined number (10 sheets in this embodiment). Determine whether or not. When the number of print jobs output exceeds 10, as shown in FIG. 5, the rotational speed of the exhaust axial flow fan 54 is reduced as compared with the case of 10 sheets or less to reduce the wind speed.

  That is, since the temperature inside the apparatus rises due to continuous printing of a predetermined number of sheets or more and the amount of volatile organic compounds generated from the resin inside the apparatus increases, the rotational speed of the exhaust axial flow fan 54 exceeds the specified value. The filter 58 is operated at a low rotational speed to collect the compound, and the collection efficiency of the volatile organic compound by the filter 58 is increased.

  Further, as shown in FIG. 5, after the print job for 20 sheets is completed, the exhaust axial flow fan 54 rotates at a low speed for a predetermined time (for example, about 30 seconds) and then operates at a high speed that is a normal rotation speed. Control is performed. This is because the temperature inside the device rises, and it takes time until the temperature falls, during which the amount of volatile organic compounds generated remains increased, and the collection efficiency of the volatile organic compounds that increased the amount generated. It is because it is necessary to raise.

  As described above, when the number of sheets to be continuously output (20 sheets in the present embodiment) exceeds a predetermined number (10 sheets in the present embodiment), the image forming apparatus 100 uses the exhaust axial flow fan. Control is performed to reduce the rotational speed of 54. Accordingly, it is possible to prevent the volatile organic compound generated from the image forming apparatus from being discharged out of the apparatus in an amount exceeding the prescribed values of various standards regardless of the number of output sheets. Moreover, even when the amount of the volatile organic compound generated from the image forming apparatus is increased or decreased by controlling the change to the collection efficiency required at the start of printing, the filter 58 can efficiently collect the volatile organic compound. It can be done well and can prolong the life of a filter with a fixed total amount that can be collected.

  In this embodiment, 20 sheets are exemplified as the number of sheets to be output continuously, and 10 sheets are exemplified as the predetermined number of sheets that serves as a reference for controlling the rotational speed of the fan. However, the present invention is limited to this. It is not a thing. The predetermined number of sheets that serves as a reference for changing the number of rotations of the fan varies depending on the type, size, thickness, arrangement, and type of recording material used in the device. It is necessary to continue.

  In the above-described embodiment, the exhaust axial flow fan 54 is controlled based on the number of prints spooled in the storage device 151, but the present invention is not limited to this. For example, in a network printer or the like using a large number of image forming apparatuses, it is possible to spool a number of print jobs for outputting an arbitrary number of sheets in the storage device (first storage unit) 150 as the storage unit. A configuration may be used, and control may be performed according to the number of jobs. That is, based on the information stored in the storage device 151, when the number of print jobs to be continuously performed exceeds a predetermined number, the speed of the air flow generated by the exhaust axial flow fan 54 is higher than when the number is less than the predetermined number. You may make it perform rotation control of the said exhaust axial flow fan 54 so that it may reduce. Even with this configuration, as described above, volatile organic compounds generated from the image forming apparatus are discharged out of the apparatus in amounts exceeding the specified values of various standards, regardless of the number of print jobs and the number of output sheets for each job. Can be prevented in advance. Moreover, even when the amount of the volatile organic compound generated from the image forming apparatus is increased or decreased by controlling the change to the collection efficiency required at the start of printing, the filter 58 can efficiently collect the volatile organic compound. It can be done well and can prolong the life of a filter with a fixed total amount that can be collected.

  In the above-described embodiment, the first storage unit (storage device 151) that temporarily stores the recording data to be output to the sheet is exemplified as the storage unit, but the output history of the output sheet is further stored. It is good also as a structure which has two memory | storage means (memory | storage device 150). The sheet output density per unit time may be calculated from the information stored in the storage devices 150 and 151, and the rotational speed of the exhaust axial flow fan 54 may be controlled based on the information. Hereinafter, this will be described in detail with an example.

  As illustrated in FIG. 1, the image forming apparatus 100 includes a storage device (second storage unit) 150 that stores a print execution history in addition to the storage device 151 as a storage unit. This counts up the time PT during which printing is being performed, and simultaneously counts up the print pause time ST (standby time). A CPU 60 as a control unit in the image forming apparatus 100 can calculate a print time ratio (PT / (PT + ST)) using the times PT and ST.

  In this embodiment, when a print job is executed, the print time ratio (PT / (PT + ST)) of a past predetermined time (30 minutes in the present embodiment) at the time when the print job ends exceeds 0.5. In other words, when the inequality (PT / (PT + ST)> 0.5) is established, control is performed to change the exhaust axial flow fan 54 to a low speed rotation as compared with the case of 0.5 or less.

  A specific state of control is shown in FIG. FIG. 6 is a control flowchart of the exhaust axial flow fan 54.

  When the image forming apparatus 100 receives a print command from a host computer such as a personal computer (PC), the image forming apparatus 100 spools the print job in the recording device 151 (step S11). The CPU 60 in the image forming apparatus 100 determines whether or not the continuous print number of the spooled print job is 10 or less (step S12).

  When the number of continuous prints is 11 or more, the CPU 60 issues a command so that the exhaust axial fan 54 rotates at a lower speed than when the number is 10 or less (step S13). When the number of continuous prints is 10 or less, the process proceeds to the next step S14. In the next step S14, the print execution ratio stored in the storage device 150 described above is added to the print execution ratio (PT / P) in consideration of the print execution time when the print job currently spooled in the storage device 151 is executed. (PT + ST)) is calculated.

  The print time ratio is calculated as a print time ratio for a predetermined time (30 minutes in this embodiment) going back from the time when the spooled print job is completed. In other words, the number of sheets output per unit time is calculated, and based on the information, how much the temperature inside the apparatus rises when the print job is completed, and the rotational speed of the exhaust axial flow fan 54 is changed at the start of printing. ing.

  That is, if the print time ratio is greater than 0.5 in step S15, a command is issued so that the exhaust axial flow fan 54 rotates at a low speed as described above (step S16). If the print time ratio is 0.5 or less, the rotational speed of the exhaust axial fan is not changed and is maintained at high speed (step S17).

  As a result, it is possible to determine before the start of printing that the generation of volatile organic compounds increases due to the temperature rise in the apparatus, and the volatile organic compounds generated from the image forming apparatus satisfy the prescribed values of various standards. Excessive amount can be prevented from being discharged out of the apparatus. Moreover, even when the amount of the volatile organic compound generated from the image forming apparatus is increased or decreased by controlling the change to the collection efficiency required at the start of printing, the filter 58 can efficiently collect the volatile organic compound. It can be done well and can prolong the life of a filter with a fixed total amount that can be collected.

  The exhaust axial flow fan 54 controlled to the low-speed rotation is controlled to rotate at a low-speed rotation for a predetermined time (about 30 seconds) after the print job is completed, and then to operate at a high-speed rotation. This is because, as described above, the temperature inside the apparatus rises, and it takes time until the temperature falls, during which time the amount of volatile organic compounds generated continues to increase, and the amount of generated volatile organics increases. This is because it is necessary to increase the collection efficiency of the compound.

  Note that the print time ratio for changing the rotational speed of the exhaust axial flow fan 54 described above is obtained experimentally, and depends on the type, size, thickness, arrangement, and type of recording material used in the apparatus. Since it varies depending on the situation, it is necessary to make an experiment and decide for each device.

  Further, in the embodiment described above, the exhaust axial flow fan is controlled using the print time ratio as the sheet output density per unit time, but the sheet per unit time as the sheet output density per unit time. Control may be performed using the number of prints.

  As described above, according to the present embodiment, the amount of the volatile organic compound generated from the resin component in the image forming apparatus that varies depending on the number of output sheets exceeds the specified values of various standards, Can be prevented in advance. Further, even when the amount of the volatile organic compound generated from the inside of the image forming apparatus is increased or decreased, the volatile organic compound can be efficiently collected by the filter 58 and the life of the filter 58 can be extended. Can do.

  In addition, the life of the filter 58 can be set longer than the life of the apparatus, and it is not necessary to replace the filter 58 that has been performed by the user in the past, so that user maintenance can be improved.

  Further, in consideration of the exchangeability by the user in the past, the arrangement of the filter 58 has been limited to the exhaust side (upstream side) of the exhaust axial flow fan 54 which is a place close to the exterior cover. As described above, since the life of the filter 58 can be set longer than the life of the apparatus, the degree of freedom in arranging the filter 58 is increased, and the upstream side of the exhaust axial flow fan 54 can be arranged. Thereby, it is possible to allow uniform air to pass through the filter due to the characteristics of the axial fan, and the collection efficiency of the volatile organic compound by the filter 58 can be improved.

  Furthermore, by changing the rotational speed of the exhaust axial flow fan 54 as a cooling fan for suppressing the temperature rise in the apparatus according to the increase in the amount of volatile organic compounds that increases as the apparatus temperature rises, the filter Since the collection efficiency of the volatile organic compound by 58 is optimized, it is possible to collect the volatile organic compound stably over the product lifetime without increasing the product cost.

[Other Embodiments]
In the above-described embodiment, the control for changing the rotational speed of the exhaust fan constituting the exhaust means to low speed or high speed based on the information related to recording of the recording material is exemplified, but the present invention is not limited to this. Control that changes stepwise in multiple steps may be used, or control that increases or decreases steplessly may be used.

  In the embodiment described above, as a process cartridge that is detachable from the main body of the image forming apparatus, a photosensitive drum, a charging unit (charging device) as a process unit that acts on the photosensitive drum, and a developing unit (developing device). , The process cartridge integrally including the cleaning unit (cleaning device) is illustrated, but is not limited thereto, and any one of the charging unit, the developing unit, and the cleaning unit may be used in addition to the photosensitive drum. It may be a process cartridge integrally having one.

  In the above-described embodiment, the color image forming picture apparatus capable of forming a color image has been described as an example. However, the present invention is not limited to this, and may be a monochrome image forming apparatus capable of forming a monochrome image. .

  In the above-described embodiments, the printer is exemplified as the image forming apparatus. However, the present invention is not limited to this, and other image forming apparatuses such as a copying machine and a facsimile machine, or a combination of these functions. Other image forming apparatuses such as multifunction peripherals may also be used. Alternatively, an image forming apparatus that uses an intermediate transfer member, sequentially transfers the toner images of each color on the intermediate transfer member, and collectively transfers the toner images carried on the intermediate transfer member onto a sheet. The same effect can be obtained by applying the present invention to the image forming apparatus.

1 is a cross-sectional view illustrating an embodiment of an image forming apparatus according to the present invention. 2A and 2B are explanatory diagrams illustrating an airflow configuration in the image forming apparatus according to the present invention, in which FIG. 1A is a top view of the image forming apparatus and FIG. 2B is a perspective view of a filter. FIG. 4A is a diagram illustrating a temperature change in the apparatus during continuous printing, and FIG. 5B is a diagram illustrating a temperature change in the apparatus when a print job is continuously performed. It is a figure which shows the characteristic of a filter. It is a figure which shows an example of rotation speed control of an exhaust axial flow fan. It is a figure which shows an example of the control flow of an exhaust axial flow fan.

Explanation of symbols

20: Fixing device (fixing means)
51 ... Intake axial flow fan 54 ... Exhaust axial flow fan (exhaust means)
55 ... Fan holder 58 ... Filter 60 ... CPU (control means)
100 ... Image forming apparatus main body 150 ... Storage device (first storage means)
151 ... Storage device (second storage means)

Claims (10)

An image forming apparatus that includes an exhaust unit for exhausting air from the inside of the apparatus to the outside of the apparatus, and a filter through which an air flow generated by the exhaust unit passes. In the device
An image forming apparatus comprising storage means for storing information relating to the number of recording materials recorded, and controlling the amount of air passing through the filter by the exhaust means based on the information stored in the storage means .   The storage means has first storage means for temporarily storing recording data to be output to the recording material, and obtains the number of output recording materials to be continuously output from the information stored in the first storage means. The image forming apparatus according to claim 1.   3. The speed of the air flow generated by the exhaust means is reduced when the number of continuously output recording materials exceeds a predetermined number as compared with the case where the number is less than the predetermined number. Image forming apparatus.   The storage means includes first storage means for temporarily storing recording data to be output to the recording material, and the number of recording jobs for outputting an arbitrary number of recording materials from the information stored in the first storage means The image forming apparatus according to claim 1, wherein:   5. The image according to claim 4, wherein when the number of continuous recording jobs exceeds a predetermined number, the speed of the air flow generated by the exhaust unit is reduced as compared with the case where the number is less than the predetermined number. Forming equipment.   The storage means has second storage means for storing the output history of the recording material, and the output density of the recording material per unit time based on the information stored in the first storage means and the second storage means. The image forming apparatus according to claim 2, wherein the image forming apparatus is obtained.   When the output density of the recording material per unit time based on the information stored in the first storage unit and the second storage unit exceeds a predetermined density, the air flow generated by the exhaust unit is less than the case where the output density is less than the predetermined density. The image forming apparatus according to claim 6, wherein the speed of the image forming apparatus decreases.   7. The recording material output density per unit time is a recording time ratio calculated from a recording execution time and a recording stop time, or the number of output recording materials per unit time. Item 8. The image forming apparatus according to Item 7.   The image forming apparatus according to claim 1, wherein the exhaust unit is an exhaust fan, and the number of revolutions of the exhaust fan is controlled based on information stored in the storage unit.   The image forming apparatus according to claim 1, wherein the filter is provided upstream of the exhaust unit with respect to an air flow generated by the exhaust unit.

Images