JP2006308744A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a volatile organic compound, generated from a resin member used in an image forming apparatus, from being generated exceeding specified values (specified quantities) of various specifications, and being discharged out of the apparatus. <P>SOLUTION: The image forming apparatus includes a cooling means for cooling the inside of the image forming apparatus, and a collecting member for collecting a volatile organic compound generated from the inside of the apparatus. In the image forming apparatus, the cooling efficiency of the cooling means is restricted in the beginning of use of the apparatus and is increased, after its use. <P>COPYRIGHT: (C)2007,JPO&INPIT

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.

  In recent years, the printing speed of color image forming apparatuses has been further increased. Then, the total amount of heat generated from an electric unit such as a motor, a power source, and a fixing device, which are heat sources in the apparatus, is increasing.

  For this purpose, the image forming apparatus is provided with an intake / exhaust fan and duct, which are cooling means for cooling the inside of the apparatus, and louvers (ventilation holes) provided in the apparatus exterior member. As for the air flow inside the device by the cooling means, air taken from outside the device is sent to a heat source (electric unit such as motor, power source, fixing device, etc.), and the air deprived of heat is exhausted outside the device. I have to.

  Further, when recording is performed on both sides of a sheet, the sheet on which recording is performed on one side passes through the image forming unit again in a state of passing heat through a high-temperature fixing device. As a result, the temperature of the image forming unit is raised, but air is also sent to the image forming unit using a fan or duct, and the air deprived of heat is exhausted outside the apparatus in the same manner 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 described above, the emission amount of substances generated in the apparatus is regulated, and a small amount of volatile organic compounds generated from resin parts used in the image forming apparatus are also regulated. Yes. Specifically, there are standards such as a BAM standard, a UL standard, and a TUV standard that regulate the emission amount of volatile organic compounds, and it is necessary to satisfy these standards even in an image forming apparatus.

  Conventionally, a lot of resin has been used for parts constituting the image forming apparatus. 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 is generated from resin parts made of ABS, PS, PC + ABS, PPE or the like used in the image forming apparatus. These resin parts are exposed to heat due to temperature rise in the apparatus due to heat generation of the drive motor, heat generation of the power supply, heat generation of the fixing device, or passing of a heated sheet during double-sided recording. This heat causes chemical substances such as styrene (boiling point 145 ° C.) and benzene (boiling point 80 ° C.), which are resin components, to reach the boiling point. The gas is then exhausted out of the apparatus through a fan or duct provided in the apparatus.

  On the other hand, 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 placed in the apparatus have been exposed to more heat than ever. ing. As a result, the amount of volatile organic compounds generated from the resin parts is also an amount that cannot be ignored.

  In general, molded resin parts are used. Molded resin parts generate the most volatile organic compounds immediately after molding, and the amount tends to decrease as time passes. Therefore, even in an image forming apparatus in which many of these resin parts are used, the amount of volatile organic compounds generated from the resin parts tends to decrease as time passes from the initial use. That is, the amount of the volatile organic compound generated from the image forming apparatus using many resin parts is not constant.

  In order to collect the volatile organic compounds generated from these resin parts, it is effective to use a collection filter mainly composed of activated carbon. The collection filter collects volatile organic compounds by physically adsorbing a gaseous substance into fine pores called pores. The collection filter collects the volatile organic compound contained in the air by allowing the air in the apparatus containing the volatile organic compound to pass through the filter.

JP 2003-186324 A

  However, the collection filter is characterized in that only a certain amount of volatile organic compounds can be collected. In addition, if the collection filter is used for a long time in the apparatus, it is possible to collect the volatile organic matter that can be collected by the original filter due to contamination by toner particles scattered from the image forming unit and gaseous substances contained in the atmosphere of the apparatus use environment. The total amount of compounds will decrease. For this reason, there was a problem that collection of a volatile organic compound could not be performed up to the filter's original volatile organic compound collection limit.

  Accordingly, an object of the present invention is to efficiently collect volatile organic compounds generated from resin parts used in an image forming apparatus.

  A typical configuration of the present invention for achieving the above object includes a cooling means for cooling the inside of the image forming apparatus, a collecting member for collecting a volatile organic compound generated from the inside of the apparatus, In the image forming apparatus, the cooling efficiency of the cooling unit is suppressed in the initial use of the image forming apparatus, and the cooling efficiency of the cooling unit is increased in the latter half of the use of the image forming apparatus.

  According to the present invention, volatile organic compounds generated from resin parts used in an image forming apparatus are prevented from being discharged out of the apparatus beyond the specified values (specified amounts) of various standards. it can.

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

(Whole image forming apparatus)
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). Around the photosensitive drum 1, a charging device 2, a scanner unit 3, a developing device 4, an electrostatic transfer unit 5, a cleaning device 6 and the like are arranged in order according to the rotation direction.

  The charging device 2 (2a, 2b, 2c, 2d) uniformly charges the surface of the photosensitive drum 1. The scanner unit 3 (3a, 3b, 3c, 3d) irradiates a laser beam based on image information to form an electrostatic latent image on the photosensitive drum 1. The developing device 4 (4a, 4b, 4c, 4d) develops a toner image by attaching toner to the electrostatic latent image. The electrostatic transfer unit 5 is a transfer unit that transfers the toner image on the photosensitive drum 1 to the transfer material S. The cleaning device 6 (6a, 6b, 6c, 6d) removes the transfer residual toner remaining on the surface of the photosensitive drum 1 after the transfer.

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

  The developing devices 4a, 4b, 4c, and 4d in each process cartridge 7 are each composed of a developing device that stores toner of each color of yellow, magenta, cyan, and black. There is a toner container for storing toner in the developing device. By transmitting the LED light into the toner container, the transmission time is detected and the remaining amount of toner is detected.

  The electrostatic transfer unit 5 includes 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: a driving roller 13, driven rollers 14a and 14b, and a tension roller 15. The electrostatic transfer belt 11 circulates and moves so that the sheet S is electrostatically attracted to the outer peripheral surface on the left side in the drawing to bring the sheet S into contact with the photosensitive drum 1. A transfer roller 12 (12a, 12b, 12c, 12d) is arranged in parallel at a position in contact with the inside of the electrostatic transfer belt 11 and facing the four photosensitive drums 1a, 1b, 1c, 1d. Accordingly, 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. A plurality of sheets S are stored in a cassette 17. During image formation, the feeding roller 18 (half moon roller) feeds the uppermost sheet S on the cassette 17. The leading edge of the fed sheet S hits the registration roller pair 19 and temporarily stops to form a loop. Thereafter, the rotation of the electrostatic transfer belt 11 and the image writing position are synchronized, and the sheet is fed to the electrostatic transfer belt 11 by the registration roller pair 19.

  A fixing unit 20 as a fixing unit fixes the toner images of a plurality of colors transferred to the sheet S. The fixing unit 20 includes a rotating heating roller 21a and a pressure roller 21b that presses against the rotating roller 21 and applies heat and pressure to the sheet S. A discharge roller pair 23 is provided downstream of the fixing unit 20 and discharges the sheet S out of the apparatus main body.

  A discharge sensor (not shown) is disposed between the fixing roller pair 21 and the discharge roller pair 23. The discharge sensor monitors whether the sheet S has been reliably discharged out of the apparatus and whether the sheet S has been wound around the fixing roller pair 21.

  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, a conveying roller pair 25, and a conveying roller pair 26 are arranged at the entrance of the duplex path, and convey the sheet S in the downward direction in the figure.

  The switching flapper 24 switches whether to discharge the sheet to the discharge unit 31 or to guide the sheet to the double-sided path. The conveyance roller pair 25 can switch back and convey the sheet guided to the double-sided path by the switching flapper 24. The conveyance roller pair 26 conveys the switchback conveyed sheet into the duplex path. 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. In response to the drive, the photosensitive drums 1a, 1b, 1c, and 1d are driven to rotate counterclockwise. Then, the scanner units 3 corresponding to the respective process cartridges 7 are sequentially driven. By this driving, the charging roller 2 applies a uniform charge to the peripheral surface of the photosensitive drum 1. The scanner unit 3 exposes the circumferential surface of the photosensitive drum according to an image signal to form an electrostatic latent image on the circumferential surface of the photosensitive drum. 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 uppermost photosensitive drum 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. In addition, the registration roller pair 19 starts rotating to feed 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. At the same time, the sheet S is configured to be electrostatically attracted to the outer periphery of the electrostatic transfer belt 11 by applying a voltage between the electrostatic transfer belt 11 and the electrostatic attracting roller 22. 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 onto the sheets S by an electric field formed between the photosensitive drums 1 and the transfer rollers 12.

  The sheet S on 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 conveying roller pair 25 and detects that the sheet S has passed 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 entering 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 by the same image forming process as the front surface recording, and the sheet S on which images are recorded on the front and back surfaces is discharged to the discharge unit 31.

(Resin parts used in image forming equipment)
The image forming apparatus 100 uses resin parts in many other places 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. Resin parts constantly discharge volatile organic compounds into the air.

(Air flow configuration)
Next, an air flow configuration in the image forming apparatus 100 will be described. FIG. 2 is an explanatory diagram showing an airflow configuration of the image forming apparatus. FIG. 2A is a top view of the image forming apparatus 100. FIG. 2B is a perspective view of the filter.

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

  Further, an exhaust cooling axial fan 54, which is an apparatus cooling unit constituting the exhaust unit, is disposed at the right rear portion of the image forming apparatus main body. The exhaust cooling axial fan 54 (80 mm square axial fan in this embodiment) rotates in a direction to exhaust the air inside the apparatus to the outside of the apparatus. The exhaust cooling axial flow fan 54 exhausts air, which has been deprived of heat by blowing to an apparatus temperature raising unit such as the image forming unit or the fixing unit 20, toward the outside of the device.

  Further, the exhaust cooling axial 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 cooling axial fan 54 is fixed by a snap fit (not shown).

  One end of the fan holder 55 is engaged with a louver 57 (ventilation hole) 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 portion 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 cooling axial flow fans 51 and 54 generate an air flow in the direction of the arrow in FIG. 2 (a), and blow the air taken from the outside of the apparatus into the apparatus to the temperature raising part in the apparatus, thereby effectively supplying the air. Exhaust outside the equipment.

  The fan holder 55 holds the exhaust cooling axial fan 54 and holds an activated carbon filter 58 as a collecting member at a position close to the exhaust cooling axial fan 54. The activated carbon filter 58 is fixed by a snap fit (not shown) formed in the fan holder 55. The activated carbon filter 58 is disposed at a predetermined distance (about 20 mm in the present embodiment) from the exhaust cooling axial fan 54 so as not to generate wind noise of the exhaust cooling axial 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, the activated carbon filter 58 is arranged on the upstream side of the air flow with respect to the exhaust cooling axial fan 54 so that the air is allowed to uniformly pass through the activated carbon filter 58.

  The activated carbon filter 58 has the same size as the exhaust cooling axial flow fan 54 (80 mm square size in this embodiment). The thickness and fineness of the activated carbon filter 58 (number of cells: number of holes per inch square) are appropriately determined by the required life and the amount of volatile organic compounds that need to be collected. . In the present embodiment, the thickness is set to 20 mm and the number of cells is set to 190.

  In addition, the activated carbon filter 58 has activated carbon in 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 activated carbon filter 58. We are using something that can be collected.

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

(Relationship between the total number of sheets S output and the temperature of resin parts and the amount of volatile organic compounds generated)
Here, the relationship between the total number of sheets S output, the temperature of the resin component, and the amount of volatile organic compounds generated will be described. FIG. 3A is a diagram showing the relationship between the total number of sheets S output from the image forming apparatus 100 and the amount of volatile organic compounds generated from the resin parts used in the image forming apparatus 100. FIG. 3B is a diagram illustrating the relationship between the temperature of the resin component used in the image forming apparatus 100 and the amount of volatile organic compounds generated from the resin component used in the image forming apparatus 100.

  As can be seen from FIG. 3 (a), many resin parts generate many volatile organic compounds immediately after being molded, but the generation amount decreases as the number of output sheets S increases. have. If the product life is 500,000, almost no volatile organic compounds are generated at the end of life (late use).

  As shown in FIG. 3B, the amount of the volatile organic compound generated from the resin component increases rapidly as the temperature of the resin component increases. This is because the resin component contains a plurality of types of volatile organic compounds having different boiling points, and each volatile organic compound rapidly vaporizes into the air as it exceeds its boiling point. . This phenomenon is the same in an image forming apparatus composed of many resin parts. As the temperature of the resin parts in the apparatus rises due to the heat source in the apparatus, the amount of volatile organic compounds generated from the apparatus increases. Increases rapidly.

(Usage time of activated carbon filter 58 and removal rate of volatile organic compounds under normal and non-degraded environments)
FIG. 4A is a diagram showing the relationship between the use time of the activated carbon filter 58 and the removal rate of volatile organic compounds by the activated carbon filter 58 under normal and non-degraded environments. Here, the normal environment is an environment in which a general user uses an image forming apparatus in a normal office or the like, and refers to an environment in which contamination due to toner particles occurs. On the other hand, the non-deteriorating environment means an environment in which no image is intentionally recorded so as not to cause contamination by toner particles and there is no gaseous substance adsorbed on the activated carbon filter 58.

  As shown in FIG. 4A, the removal rate of the activated carbon filter 58 in the normal environment is deteriorated faster than the removal rate of the activated carbon filter in the non-deteriorated environment. This is because, under a normal environment, the original collection performance of the activated carbon filter 58 cannot be sufficiently exhibited due to contamination by toner particles scattered from the image forming unit or adsorption of gaseous substances in the air.

(Variable control of cooling efficiency by equipment cooling means)
Next, variable control of the cooling efficiency by the apparatus cooling means for efficiently collecting the volatile organic compound by the activated carbon filter 58 will be described.

  First, at the initial stage of use, control is performed to reduce the rotational speed of the cooling axial flow fans 51 and 54 as the apparatus cooling means. Thereby, cooling efficiency falls and the temperature of the resin component which is a generation source of a volatile organic compound rises. When the temperature of the resin component rises, the vaporization of chemical substances such as styrene and benzene, which are resin components, is promoted, and many volatile organic compounds are generated. In the initial use of the image forming apparatus, volatile organic compounds exhausted from the apparatus are reliably collected.

  Thereafter, as the usage time becomes longer (as the total number of sheets S output from the image forming apparatus 100 increases), the amount of volatile organic compounds generated from the resin parts decreases. Further, the activated carbon filter 58 is deteriorated due to adhesion of toner particles, gaseous substances in the air in the environment where the apparatus is used, and the like.

  Therefore, as the usage time becomes longer (as the total number of sheets output from the image forming apparatus increases), conversely, control is performed to increase the rotational speed of the cooling axial fans 51 and 54. As a result, the cooling efficiency is increased, the temperature of the resin component is hardly increased, the vaporization of chemical substances such as styrene and benzene, which are resin components, is suppressed, and the generation of volatile organic compounds is suppressed. Moreover, it becomes difficult for the temperature inside the apparatus to rise to a predetermined limit temperature. Thereby, even the deteriorated activated carbon filter 58 having a weak collecting power can sufficiently suppress the volatile organic compounds in the air exhausted from the apparatus.

  That is, almost all volatile organic compounds are generated before the activated carbon filter 58 is deteriorated due to toner contamination or the like. The generated volatile organic compound is collected by the activated carbon filter 58 in which the collecting power is not reduced. As a result, when the activated carbon filter 58 is deteriorated due to toner contamination or the like, almost no volatile organic compound is generated, and the volatile organic compound in the air exhausted outside the apparatus can be suppressed throughout the life of the apparatus. .

(Control to limit temperature or less)
However, in order to form a high-quality image in the apparatus, it is necessary to keep the image forming portion temperature below a predetermined limit temperature. For this reason, if the cooling efficiency is lowered and the image forming unit temperature reaches a predetermined limit temperature, the cooling axial fan is used so that the cooling efficiency is temporarily increased so that the temperature inside the apparatus does not easily rise above the predetermined limit temperature. 51 and 54 are controlled.

  FIG. 6 is a flowchart for controlling the inside of the apparatus below the limit temperature. As such control, for example, as shown in FIG. 6, after printing is started, it is first determined whether the total number of output sheets has reached a predetermined number (S1). Here, there are a plurality of patterns for setting the predetermined number as shown in FIG.

  If the total number of output sheets exceeds the predetermined number in S1, the rotational speed of the cooling axial fans 51 and 54 is increased to a predetermined rotational speed with high cooling efficiency (S5). On the other hand, if the total number of output sheets is less than or equal to the predetermined number in S1, the cooling axial fans 51 and 54 are rotated at the number of rotations corresponding to the predetermined number (S2). Then, it is determined whether the inside of the apparatus has reached the limit temperature (S3).

  If the temperature inside the apparatus exceeds the limit temperature in S3, the rotational speed of the cooling axial fans 51 and 54 is increased to a predetermined rotational speed with high cooling efficiency (S5). On the other hand, if the inside of the apparatus is below the limit temperature in S3, the cooling axial fans 51 and 54 are continuously rotated at a predetermined rotational speed (S4).

  Then, by repeating the operations of S1 to S5 until the end of printing, the inside of the apparatus is controlled to the limit temperature below.

(Total number of output sheets and cooling fan speeds 51 and 54)
Here, a specific method for optimizing the collection efficiency by the activated carbon filter 58 will be described. FIG. 4B is a diagram showing the relationship between the total number of output sheets of the image forming apparatus 100 and the rotational speeds of the cooling axial fans 51 and 54. As shown in FIG. 4B, the cooling axial fans 51 and 54 are controlled so that the rotational speed is changed stepwise and the wind speed is changed stepwise (in this embodiment, five steps). ). The cooling axial fans 51 and 54 are controlled by a control unit 60 (control unit) that controls each unit of the entire image forming apparatus.

  The control unit 60 of the image forming apparatus 100 includes a counter 61 that counts the number of output sheets and a storage unit 62 that stores the total number of output sheets counted by the counter 61. When the total number of output sheets of the image forming apparatus 100 reaches a predetermined number, as shown in FIG. 4B, the rotational speed of the cooling axial fans 51 and 54 is increased by one step to increase the wind speed, thereby forming an image. Control is performed to increase the cooling efficiency so that the temperature of the part does not easily reach a predetermined temperature.

  Thereafter, the amount of volatile organic compounds generated decreases with time, so that the cooling efficiency is increased by increasing the rotational speed of the cooling axial fans 51 and 54 each time the total output number reaches a certain number. . Then, at the time when the collection effect of the activated carbon filter 58 is finally lost, control is performed so that the rotational speed of the cooling axial fans 51 and 54 becomes the maximum rotational speed. At this time, almost no volatile organic compound is generated.

  However, as described above, the image forming unit needs to be kept below the limit temperature in order to form a high quality image. Therefore, when the cooling efficiency is lowered, it is necessary to temporarily increase the cooling efficiency so that the temperature does not exceed the temperature when the image forming unit reaches the limit temperature, or to periodically stop the image forming apparatus so-called throughput reduction. is there.

  However, this operation should be eliminated as much as possible for the user as a waiting time. Therefore, as the amount of volatile organic compounds generated from the device decreases (as the total number of output from the device increases), the cooling axial fans 51 and 54 rotate so as to increase the cooling efficiency and keep the temperature inside the device low. Make the number work high.

  Note that the predetermined number of output sheets that serves as a reference for changing the rotational speed of the cooling axial fans 51 and 54 depends on the amount of volatile organic compounds that decrease over time and the amount of volatile organic compounds collected by the activated carbon filter 58. Therefore, it is required experimentally. For this reason, it differs depending on the type, size, thickness, arrangement, and type and size of the activated carbon filter 58 used for the components constituting the image forming apparatus. For this reason, it is necessary to make an experiment and decide for each product.

  FIG. 5 is a diagram showing the relationship between the number of output devices and the temperature inside the device when fan control is performed. FIG. 5A is a diagram showing the relationship between the number of output devices and the temperature in the device at the initial setting of the device. FIG. 5B is a diagram showing the relationship between the number of output devices and the temperature inside the device when the device is used late.

  As shown in FIG. 5, in the apparatus initial setting, the cooling efficiency is lowered, so that the resin component temperature in the apparatus rises quickly. The time to reach the predetermined temperature t, which is the limit temperature, is about ½ shorter than the late stage of device use in the device use initial setting. That is, the number of output sheets that reach the predetermined temperature t, which is the limit temperature, is about ½ less than in the latter half of the use of the apparatus.

  As described above, according to the present invention, it is possible to efficiently collect volatile organic compounds generated from resin parts used in the image forming apparatus. Moreover, it is possible to reduce discharge | emission amount of a volatile organic compound over a product life (from the initial stage of use to the latter stage). Further, efficient collection of volatile organic compounds by the activated carbon filter 58 can be performed. Furthermore, the size of the activated carbon filter can be made smaller than before, and the product cost can be reduced.

  Further, before the activated carbon filter 58 is deteriorated, volatile organic compounds exceeding the specified value are collected. For this reason, it is not necessary to replace the activated carbon filter 58 that has been performed by a user in the past, and user maintenance can be improved.

  Further, in the latter stage of use of the image forming apparatus, by increasing the cooling efficiency and lengthening the time until the temperature in the image forming apparatus reaches a predetermined temperature, the generation amount of volatile organic compounds is further reduced, and the activated carbon filter Even if 58 deteriorates, volatile organic compounds in the air exhausted outside the apparatus can be suppressed.

  Furthermore, in the past, considering the exchangeability by the user and the contamination of the activated carbon filter 58 by toner particles from the image forming unit, the arrangement of the activated carbon filter 58 is located on the exhaust side of the exhaust cooling axial fan 54, which is located in the vicinity of the exterior cover. It was limited to. However, according to the present embodiment, since the volatile organic compound is collected before the activated carbon filter 58 is deteriorated, the degree of freedom of arrangement of the activated carbon filter 58 is increased, and the exhaust cooling axial flow fan 54 is disposed on the intake side. Is possible. Thereby, it is possible to allow uniform air to pass through the activated carbon filter 58 due to the characteristics of the axial fan, and the collection efficiency of the volatile organic compound by the activated carbon filter 58 can be further improved.

  In this embodiment, the collection efficiency is controlled by changing the rotational speed of the exhaust axial flow fan 54 in accordance with the total number of prints output by the image forming apparatus 100, but the present invention is not limited to this. It is not something. For example, instead of the counter 61 that counts the number of output sheets, a timer that measures the time (timer value) from when the power is first turned on may be provided. Then, the timer value measured by the timer is stored in the storage unit, and the cooling efficiency is controlled by changing the rotation speed of the cooling axial flow fans 51 and 54 at predetermined time intervals according to the timer value. Control the amount of organic compounds generated.

  Further, the total energization time during which the power is turned on may be measured, and the cooling efficiency may be controlled according to the value. The timer value and the total energization time substantially coincide with the usage time of the activated carbon filter 58, and as shown in FIG. 4A, the activated carbon filter 58 deteriorates as the usage time elapses. On the other hand, there are cases in which a large amount of printing is always performed and cases in which printing is not always performed. That is, when a large amount is not always printed, the amount of volatile organic compounds generated is reduced with a smaller number of output sheets than when a large amount is always printed. For this reason, when a large amount of printing is not always performed, the number of volatile organic compounds collected by the activated carbon filter 58 is controlled by controlling the rotational speed of the cooling axial flow fans 51 and 54 using the timer value and the total energization time. Efficiency can be further improved.

  Furthermore, it is also effective to control the cooling axial fans 51 and 54 using the one that reaches earlier among the predetermined number of sheets and the predetermined time based on both the total number of printed sheets and the timer value. In other words, even if the device is used both for printing a large amount of paper at all times and when it is not, it is possible to predict the change in the volatile organic compound emissions more accurately by combining the total number of prints and a timer. it can. Then, by controlling the cooling axial flow fan in accordance with the predicted generation amount of the volatile organic compound, the collection efficiency of the volatile organic compound by the activated carbon filter 58 can be further improved.

  Moreover, in order to control the quantity of the volatile organic compound generated from the resin component used in the apparatus, the control for changing the rotational speed of the cooling fan constituting the cooling means in stages is illustrated. However, the present invention is not limited to this. For example, the control may be changed steplessly.

  Moreover, although the structure which controls a cooling efficiency using a cooling axial flow fan as a cooling means was illustrated, this invention is not limited to this. For example, the cooling efficiency is controlled by temporarily shielding air passages (intake / exhaust ducts) provided in the image forming apparatus and intake / exhaust ventilation holes (louvers) provided in the exterior member of the image forming apparatus. May be.

  Further, 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.

  Further, although a printer is exemplified as the image forming apparatus, the present invention is not limited to this. For example, the image forming apparatus may be another image forming apparatus such as a copying machine or a facsimile machine, or another image forming apparatus such as a multi-function machine combining these functions. Alternatively, an image forming apparatus that uses an intermediate transfer body, sequentially transfers the toner images of the respective colors on the intermediate transfer body, and collectively transfers the toner images carried on the intermediate transfer body onto a sheet may be used. The same effect can be obtained by applying the present invention to such an image forming apparatus.

1 is a cross-sectional view of an image forming apparatus according to an embodiment. FIG. 2A is a top view inside an image forming apparatus for explaining an airflow configuration. (B) is a perspective view of a filter. (A) is a figure which shows the relationship between apparatus use time and the generation amount of a volatile organic compound. (B) is a figure which shows the relationship between resin component temperature and the generation amount of a volatile organic compound. (A) is a figure which shows the relationship between apparatus use time and a volatile organic compound removal rate, (b) is a figure which shows apparatus use time and rotation speed control of a cooling axial flow fan. (A) is a figure which shows the relationship between the apparatus output number at the time of apparatus use initial setting, and apparatus internal temperature, (b) is a figure which shows the relationship between the apparatus output number at the time of apparatus use late setting, and apparatus internal temperature. It is a flowchart which controls the inside of an apparatus to a limit temperature below.

Explanation of symbols

S ... sheet 1 ... photosensitive drum 2 ... charging device 3 ... scanner unit 4 ... developing device 5 ... electrostatic transfer unit 6 ... cleaning device 7 ... process cartridge
11… Electrostatic transfer belt
12… Transfer roller
13… Drive roller
14… driven roller
15… Tension roller
16… Feeding department
17… cassette
18… feed roller
19… Registration roller pair
20… Fixing part
21a ... Heating roller
21b… Pressure roller
23… discharge roller pair
24… Switching flapper
25… Conveying roller pair
26… Conveying roller pair
30… U-turn pass
31… discharge section
51… Axial cooling axial flow fan (supports cooling means)
52… Left cover
53… Louver
54… Exhaust cooling axial fan (supports cooling means)
55… Fan holder
56… Rear cover
57… Louver
58… Activated carbon filter
60… Control part
61… Counter
62… Memory part
100 ... Image forming apparatus

Claims (8)

In an image forming apparatus having a cooling means for cooling the inside of the image forming apparatus, and a collecting member for collecting a volatile organic compound generated from the inside of the apparatus,
An image forming apparatus characterized in that the cooling efficiency of the cooling means is suppressed in the early stage of use of the image forming apparatus, and the cooling efficiency of the cooling means is increased in the later stage of use of the image forming apparatus. A counter that counts the total number of sheets output from the image forming apparatus;
The image forming apparatus according to claim 1, wherein the cooling efficiency of the cooling unit is increased as the total number of output sheets counted by the counter increases. A timer for measuring the usage time of the image forming apparatus;
The image forming apparatus according to claim 1, wherein the cooling efficiency of the cooling unit is increased as the usage time of the image forming apparatus measured by the timer becomes longer. A timer for measuring the usage time of the image forming apparatus;
A counter that counts the total number of sheets output from the image forming apparatus,
2. The image forming apparatus according to claim 1, wherein the cooling efficiency of the cooling unit is increased as the total number of output sheets counted by the counter increases and the usage time of the image forming apparatus measured by the timer increases. . 5. The apparatus according to claim 1, wherein the cooling unit is controlled to increase cooling efficiency and to increase the time until the temperature in the image forming apparatus reaches a predetermined temperature. Image forming apparatus. The image forming apparatus according to claim 1, wherein the cooling unit is a fan provided in the image forming apparatus. 6. The image forming apparatus according to claim 5, wherein the collecting member is disposed on an intake side of the fan. 5. The cooling means is an air passage provided in the image forming apparatus or an air intake / exhaust vent hole provided in an exterior member of the image forming apparatus. 2. The image forming apparatus according to item 1.

Images