JP2016051000A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can perform efficient image formation.SOLUTION: When a digital composite machine 11 receives a request for image formation (S12), a control part 12 first detects the temperature of a heat roller 51 with a temperature detection sensor 54 (S13), and then determines whether or not the temperature of the heat roller 51 is 170°C or more (S14). When determined that the temperature of the heat roller 51 is less than 170°C (NO in S14), the control part 12 first starts energization to a heater 52 (S15) and starts measuring an energization time to the heater 52 with a timer 23 (S16), and when the energization time to the heater 52 remains three minutes or more (YES in S17), applies a voltage to an exhaust fan 63 (S18).SELECTED DRAWING: Figure 6

Description

  The present invention relates to an image forming apparatus.

  In an image forming apparatus typified by a digital multifunction peripheral or the like, an image of a document is read by an image reading unit, and then an electrostatic latent image is formed on a photoconductor based on the read image. Thereafter, a developer such as charged toner is supplied onto the formed electrostatic latent image to form a visible image, and then the visible image is transferred onto a sheet, fixed by a fixing device, and discharged outside the device. The fixing device is heated to a high temperature in order to fix the visible image on the paper by heat at the time of fixing.

  From a component fixed to a fixing device heated to a high temperature or a developer fixed on paper, a volatile organic compound such as siloxane gas (hereinafter sometimes referred to as “VOC (Volatile Organic Compounds)”) or a volatile substance is included. Microparticles (hereinafter sometimes referred to as “UFP (Ultra Fine Particle)”) are generated. For such air containing UFP, for example, from the viewpoint of the German environmental label standard, it is necessary to remove UFP to a required level and then discharge it outside the image forming apparatus.

  Japanese Patent Application Laid-Open No. 2010-276904 (Patent Document 1) discloses a technique relating to discharge of volatile substances, VOCs, and semi-volatile organic compounds (SVOC (Semi-Volatile Organic Compounds)) generated in a fixing device in an image forming apparatus. And JP 2011-145576 A (Patent Document 2).

  According to Patent Document 1, a housing, an image forming unit that forms an unfixed image on an image support material, and an image support material that passes through the image support material and heats the unfixed image formed on the image support material A fixing device for fixing to a support material, an exhaust duct for exhausting air in the vicinity of the fixing device to the outside of the housing, and a suction member for sucking air in the vicinity of the fixing device and circulating the sucked air inside the exhaust duct And an image forming apparatus provided with a first filter unit provided inside the exhaust duct and carrying a polar adsorbent that adsorbs a polar substance.

  Patent Document 2 includes an exhaust passage for exhausting air in the vicinity of the fixing device to the outside of the image forming apparatus main body in an image forming apparatus including a fixing device that melts and fixes a toner image formed on a sheet. An image forming apparatus is disclosed in which the exhaust passage has an air retention portion that retains the air in the exhaust passage in at least one location inside the exhaust passage.

JP 2010-276904 A JP 2011-145576 A

  According to Patent Document 1 and Patent Document 2, when the air in the vicinity of the fixing device is exhausted through the exhaust duct, polar substances contained in the air are adsorbed by a filter and discharged out of the device. In this case, air in the exhaust duct is sucked by a fan as a suction member used for exhaust, and the air in the vicinity of the fixing device is exhausted.

  However, according to such a configuration, air flows from other regions in the vicinity of the fixing device, and as a result, the temperature of the air around the fixing device decreases. In this case, in many cases, an excessive amount of power is supplied to the heater that heats the fixing device in an attempt to maintain the temperature of the fixing device at a set temperature suitable for fixing. As a result, it is difficult to perform efficient image formation.

  An object of the present invention is to provide an image forming apparatus capable of performing efficient image formation.

  The inventor of the present application pondered factors that cause a large amount of UFP including VOC and the like from the viewpoint of efficient image formation. As a result of intensive studies, the inventors have come to the idea that there is a correlation between the time required for heating the fixing unit, that is, the heating time of the fixing unit and the amount of UFP generated, and the present invention has been configured.

  That is, the image forming apparatus according to the present invention generates an image forming unit that forms a visible image of toner on a sheet, a fixing unit that fixes the visible image formed by the image forming unit on the sheet with heat, and generates heat when energized. A heating unit that heats the fixing unit, a temperature detection unit that detects the temperature of the fixing unit, a time measurement unit that measures the time to energize the heating unit, and an exhaust unit that exhausts the area where the fixing unit is disposed If the temperature of the fixing unit detected by the temperature detection unit is lower than the predetermined temperature, energization to the heating unit is started, and the exhaust efficiency by the exhaust unit is controlled according to the time to energize the heating unit by the time measurement unit A control unit.

  According to such an image forming apparatus, when the temperature of the fixing unit detected by the temperature detection unit is lower than a predetermined temperature with respect to the removal of the UFP generated in the area where the fixing unit is disposed by the exhaust, the energization to the heating unit is performed. The exhaust efficiency of the exhaust unit is controlled according to the time for energizing the heating unit that heats the fixing unit measured by the time measurement unit. Then, for example, when it takes a long time to energize the heating unit and the amount of UFP generated is considered to be relatively large, the exhaust efficiency by the exhaust unit is increased, and exhaust when a large amount of UFP is generated is efficiently performed. be able to. In addition, when the time for energizing the heating unit is short and the amount of UFP generated is considered to be relatively small, the exhaust efficiency of the exhaust unit is lowered, and the air flows into the area where the fixing unit is disposed by exhaust. It is possible to prevent a decrease in the temperature of the fixing unit. Therefore, the image forming apparatus having such a configuration can perform efficient image formation.

  According to such an image forming apparatus, when the temperature of the fixing unit detected by the temperature detection unit is lower than a predetermined temperature with respect to the removal of the UFP generated in the area where the fixing unit is disposed by the exhaust, the energization to the heating unit is performed. The exhaust efficiency of the exhaust unit is controlled according to the time for energizing the heating unit that heats the fixing unit measured by the time measurement unit. Then, for example, when it takes a long time to energize the heating unit and the amount of UFP generated is considered to be relatively large, the exhaust efficiency by the exhaust unit is increased, and exhaust when a large amount of UFP is generated is efficiently performed. be able to. In addition, when the time for energizing the heating unit is short and the amount of UFP generated is considered to be relatively small, the exhaust efficiency of the exhaust unit is lowered, and the air flows into the area where the fixing unit is disposed by exhaust. It is possible to prevent a decrease in the temperature of the fixing unit. Therefore, the image forming apparatus having such a configuration can perform efficient image formation.

1 is a schematic diagram showing an external appearance of a digital multifunction peripheral when an image forming apparatus according to an embodiment of the present invention is applied to the digital multifunction peripheral. 1 is a block diagram illustrating a configuration of a digital multifunction peripheral when an image forming apparatus according to an embodiment of the present invention is applied to the digital multifunction peripheral. 1 is a diagram illustrating a schematic configuration of an image forming unit, a fixing unit, and an exhaust unit provided in a digital multi-function peripheral when an image forming apparatus according to an embodiment of the present invention is applied to the digital multi-function peripheral. FIG. 3 is an enlarged view showing a schematic configuration of a fixing unit and an exhaust unit, and mainly shows a case where viewed from the side. FIG. 2 is an enlarged view showing a schematic configuration of a fixing unit and an exhaust unit, and mainly shows a case when viewed from above. 4 is a flowchart showing the contents of processing when an image is formed using the image forming apparatus according to the embodiment of the present invention. It is a graph which shows the relationship between the generation amount of UFP, and the elapsed time after starting energization. 4 is a flowchart showing the contents of processing when an image is formed using the image forming apparatus according to the embodiment of the present invention. FIG. 5 is a diagram illustrating a schematic configuration of an image forming unit, a fixing unit, and an exhaust unit provided in a digital multi-function peripheral when an image forming apparatus according to another embodiment of the present invention is applied to the digital multi-function peripheral.

  Embodiments of the invention will be described below. First, the configuration of a digital multifunction peripheral when the image forming apparatus according to an embodiment of the present invention is applied to the digital multifunction peripheral will be described. FIG. 1 is a schematic diagram showing an external appearance of a digital multifunction peripheral when an image forming apparatus according to an embodiment of the present invention is applied to the digital multifunction peripheral. FIG. 2 is a block diagram showing a configuration of the digital multifunction peripheral when the image forming apparatus according to the embodiment of the present invention is applied to the digital multifunction peripheral.

  1 and 2, the digital multi-function peripheral 11 includes a timer 23 that measures time, a control unit 12 that controls the entire digital multi-function peripheral 11, information transmitted from the digital multi-function peripheral 11 side, and users A display screen 21 for displaying the input contents of the image forming apparatus, an operation unit 13 for inputting image forming conditions such as the number of copies and gradation, and power on / off, and an ADF that automatically conveys the set original to the reading unit. (Auto Document Feeder) 22, an image reading unit 14 that reads an image of a document, an image forming unit 15 that forms a visible image using toner based on the read image and image data transmitted via the network 25, A fixing unit 19 that fixes a visible image formed by the image forming unit 15 on a sheet, and an exhaust that exhausts an area where the fixing unit 19 is disposed. A unit 61; a hard disk 16 for storing transmitted image data and input image forming conditions; a facsimile communication unit 17 connected to the public line 24 for facsimile transmission and reception; A network interface unit 18 for connection and three paper feed cassettes 31, 32, and 33 for storing a plurality of sheets to be conveyed to the image forming unit 15 are provided. The digital multi-function peripheral 11 includes a DRAM (Dynamic Random Access Memory) for writing and reading image data, and the illustration and description thereof are omitted. In addition, arrows in FIG. 2 indicate the flow of data regarding control signals, control, and images. Note that sheets of different sizes are stored in the sheet cassettes 31, 32, and 33, respectively.

  The digital multifunction machine 11 operates as a copying machine by forming an image in the image forming unit 15 using the original read by the image reading unit 14. Further, the digital multifunction peripheral 11 forms an image in the image forming unit 15 and prints it on a sheet using image data transmitted from the computers 26a, 26b, and 26c connected to the network 25 through the network interface unit 18. It works as a printer. Further, the digital multifunction peripheral 11 forms an image in the image forming unit 15 via the DRAM using the image data transmitted from the public line 24 through the facsimile communication unit 17, and also by the image reading unit 14. The image data of the read original is transmitted to the public line 24 through the facsimile communication unit 17, thereby operating as a facsimile apparatus. That is, the digital multifunction peripheral 11 has a plurality of functions such as a copying function, a printer function, and a facsimile function with respect to image processing. Further, each function has functions that can be set in detail.

  The image forming system 27 including the digital multifunction peripheral 11 includes the digital multifunction peripheral 11 and a plurality of computers 26a, 26b, and 26c. Specifically, the image forming system 27 includes the digital multifunction peripheral 11 having the above-described configuration and a plurality of computers 26 a, 26 b, and 26 c connected to the digital multifunction peripheral 11 via the network 25. In this embodiment, three computers 26a to 26c are shown. Each of the computers 26 a to 26 c can print by making a print request to the digital multi-function peripheral 11 via the network 25. The digital multi-function peripheral 11 and the computers 26a to 26c may be connected by wire using a LAN (Local Area Network) cable or the like, or may be connected wirelessly. A configuration in which a digital multifunction peripheral or a server is connected may be used.

  Next, the configuration of the image forming unit 15, the fixing unit 19, and the exhaust unit 61 will be described in more detail. FIG. 3 is a diagram illustrating a schematic configuration of the image forming unit 15, the fixing unit 19, and the exhaust unit 61. In FIG. 3, the image forming unit 15 is indicated by a one-dot chain line.

Referring to FIG. 3, the image forming unit 15 includes a photoreceptor 41 that forms an electrostatic latent image on the surface thereof, a charging unit 42 that charges the surface of the photoreceptor 41, a developing sleeve, and a plurality of stirring rollers. A developer 43 for supplying a developer such as toner to the surface of the photoreceptor 41 on which the electrostatic latent image is formed to form a visible image using the toner, a transfer charger and a separation charger, and the surface of the photoreceptor 41 The transfer unit 44 that transfers the visible image formed on the sheet 34 to the conveyed sheet 34 and a static elimination roller, a cleaning blade, etc., and remained on the surface of the photoreceptor 41 after transfer of the visible image to the sheet 34. And a cleaning unit 45 that removes toner, residual charges, and the like. Photoreceptor 41 rotates in the direction of the arrow R ₁ in FIG. The image forming unit 15 forms an electrostatic latent image on the photoreceptor 41 based on the image read by the image reading unit 14. The image forming unit 15 supplies toner to the electrostatic latent image formed on the photoconductor 41 to form a visible image using the toner. The image forming unit 15 repeats charging, developing, transferring, and cleaning around the photosensitive member 41 to form a visible image with toner on the conveyed paper 34. Note that the toner consumed by the development is supplied to the developing unit 43 as needed by a toner container (not shown) detachably provided in the image forming unit 15.

  The digital multifunction machine 11 is provided with a conveyance belt 46 provided between the image forming unit 15 and the fixing unit 19 and a plurality of paper feed rollers 47a, 47b, 47c, 47d, and 47e. For example, the paper 34 set on the manual feed tray 35 is transported through the paper transport paths 48 a, 48 b, 48 c, and 48 d by the paper feed rollers 47 a to 47 e and is discharged to the discharge tray 36. Further, the paper 34 set in the paper feed cassettes 31 to 33 is transported through the paper transport paths 48 b to 48 e by the paper feed rollers 47 b to 47 e and is discharged to the discharge tray 36.

  Next, the configuration of the fixing unit 19 and the exhaust unit 61 will be described. 4 and 5 are enlarged views showing the schematic configuration of the fixing unit 19 and the exhaust unit 61. FIG. FIG. 4 mainly shows a case where the fixing unit 19 and the exhaust unit 61 are viewed from the side. FIG. 5 mainly shows a case where the fixing unit 19 is viewed from above.

  3 to 5, the fixing unit 19 includes a rotatable heat roller 51 that is heated to a predetermined temperature, a rotatable pressure roller 53 that is heated to a predetermined temperature, and the heat roller 51 and the pressure roller. A heater 52 as a heating unit for heating 53 and a temperature detection sensor 54 for detecting the temperature of the heat roller 51 are included. That is, the fixing unit 19 includes a pair of rollers, a heat roller 51 and a pressure roller 53. A sheet 34 on which a visible image is transferred by toner is passed between a heat roller 51 and a pressure roller 53 each heated to a predetermined temperature, and the visible image 37 is fixed on the sheet 34. In the state where the paper 34 is not passed, the heat roller 51 and the pressure roller 53 are in contact with each other.

  The heat roller 51 has a cylindrical shaft center portion 55, an elastic portion 56 that is provided on the outer diameter side of the shaft center portion 55 and has elasticity, and is provided on the outer diameter side of the elastic portion 56. 53 and a surface layer portion 57 in contact with 53. At the time of fixing, the visible image 37 by the toner formed on the paper 34 comes into contact with the surface layer portion 57 of the heat roller 51. A heater 52 is disposed inside the axial center portion 55 of the heat roller 51. The material of the elastic part 56 is, for example, silicone rubber. Moreover, as the surface layer part 57, a PFA tube is used, for example. A temperature detection sensor 54 that detects the temperature of the surface of the heat roller 51 is provided on the surface of the heat roller 51 where the paper 34 is not passed.

  The pressure roller 53 is composed of a rubber-like columnar member having elasticity. Since the heat roller 51 and the pressure roller 53 are in contact with each other when the paper 34 is not passed, the heat of the heat roller 51 is transmitted to the pressure roller 53. That is, the heat roller 51 and the pressure roller 53 are almost the same temperature. Although not shown, the pressure roller 53 is configured to have a crowning shape in which the central portion in the longitudinal direction slightly bulges to the outer diameter side from both end portions in the longitudinal direction.

Pressure roller 53 is rotated in the direction of the arrow R ₂ in FIG. The heat roller 51 rotates in the direction opposite to that of the pressure roller 53. By the rotation of the heat roller 51 and the pressure roller 53, the paper 34 is conveyed from the right side to the left side in FIG. During this conveyance, the visible image 37 formed on the paper 34 by the heat roller 51 and the pressure roller 53 is fixed to the paper 34.

  By energizing the heater 52, the heat roller 51 and the pressure roller 53 are heated to a predetermined set temperature suitable for fixing. For example, as the predetermined set temperature, 170 ° C. suitable for fixing is selected. By controlling the energization state of the heater 52, the temperatures of the heat roller 51 and the pressure roller 53 are controlled. As for energization of the heater 52, energization is continuously performed when the temperature detected by the temperature detection sensor 54 is far from a predetermined set temperature. In this way, the temperature of the heat roller 51 and the pressure roller 53 is rapidly increased. On the other hand, when the temperature detected by the temperature detection sensor 54 approaches a predetermined set temperature, the energization state is intermittently controlled in consideration of overshoot and the like. In other words, the heater 52 is controlled to be appropriately turned on and off. In this way, the heat roller 51 and the pressure roller 53 are controlled so as to quickly reach a predetermined set temperature suitable for fixing.

  The fixing unit 19 includes a pair of cap portions 59 a and 59 b that cover both end portions 58 a and 58 b of the heat roller 51. Each of the cap portions 59a and 59b has a substantially disc shape, and a through-hole penetrating in the thickness direction is provided at the center on the inner diameter side. The cap part 59a is attached to the one end part 58a side of the heat roller 51 via the bearing 60a so that the shaft center part 55 is disposed in the region where the through hole is provided. Similarly, the cap part 59b is attached to the other end part 58b side of the heat roller 51 through the bearing 60b so that the shaft center part 55 is arranged in the region where the through hole is provided. By the cap portions 59a and 59b, it is possible to suppress the air containing a large amount of UFP generated from the heat roller 51 in the direction of the arrow in FIG.

  On the other hand, the cap portion 59a attached to the end portion is provided with an opening 66 communicating with an exhaust duct 62 described later. With this opening 66, air containing a large amount of UFP generated from the heat roller 51 in the fixing unit 19 can be actively sent to the exhaust duct 62 described later.

The digital multifunction machine 11 includes an exhaust unit 61 that exhausts an area where the fixing unit 19 is disposed. The exhaust unit 61 is provided in the exhaust duct 62 communicating with the outside of the digital multi-function peripheral 11 from the area where the fixing unit 19 is disposed, the exhaust fan 63 that rotates by application of voltage, and the UFP. And a filter 64 as an adsorbing member to be adsorbed. The filter 64 is provided in the exhaust duct 62 between the opening 65 of the exhaust duct 62 outside the digital multifunction peripheral 11 and the exhaust fan 63. Air heated including UFP generated in the fixing unit 19, by the rotation of the exhaust fan 63 is sucked in the direction of arrow D ₂ in FIG. Then, through the filter 64, it is conveyed in the direction of arrow D _3, and is discharged from the opening 65 to the digital multifunction peripheral 11 outside. When passing through the filter 64, a large amount of UFP contained in the air is adsorbed by the filter 64. In addition, by this exhaust process, the heated air including UFP generated in the fixing unit 19 is cooled to some extent and is also adsorbed on the wall surface of the exhaust duct 62.

  Here, the control unit 12 controls the exhaust efficiency of the exhaust unit 61 in accordance with the time for energizing the heater 52 measured by the timer 23. Specifically, if the time for which the heater 52 continuously energized by the timer 23 is longer than 3 minutes, the control unit 12 applies 0 V, that is, the voltage applied to the exhaust fan 63. Control is performed so that the voltage to be applied is increased to 24 V from the absence of the voltage.

  Next, a case where an image is formed using the digital multifunction peripheral 11 according to an embodiment of the present invention will be described. FIG. 6 is a flowchart showing the contents of processing when the user forms an image.

  Referring to FIG. 6 and the like, the digital multifunction peripheral 11 is activated (in FIG. 6, step S11, hereinafter “step” is omitted), and the digital multifunction peripheral 11 accepts a request for image formation (S12).

  Then, the control unit 12 first detects the temperature of the heat roller 51 by the temperature detection sensor 54 (S13). Then, it is determined whether or not the temperature of the heat roller 51 is not less than 170 ° C., which is an appropriate fixing temperature in the digital multifunction machine 11 (S14). For example, if it is determined that the temperature of the heat roller 51 is 170 ° C. or higher, such as when the time has not passed since the previous image formation (YES in S14), the image is formed as it is (S19). The process ends.

  On the other hand, if it is determined that the temperature of the heat roller 51 is less than 170 ° C., such as when the heat roller 51 has cooled since a long time has passed since the previous image formation (NO in S14), first, the heater Energization to 52 is started (S15). The heat roller 51 and the pressure roller 53 are heated by energizing the heater 52. Moreover, the measurement of the energization time to the heater 52 is started by the timer 23 (S16). If the energization time to heater 52 is 3 minutes or longer (YES in S17), a voltage is applied to exhaust fan 63 (S18). That is, a voltage is applied to the exhaust fan 63 to rotate the exhaust fan 63 and exhaust air in a region where the fixing unit 19 is disposed. If the energization time is less than 3 minutes (NO in S17), the heater 52 is energized as it is without applying voltage to the exhaust fan 63, and the heat roller 51 and the pressure roller 53 are heated. In this way, an image is formed after waiting until the temperature of the heat roller 51 reaches 170 ° C. or higher (S19).

  According to such a digital multi-function peripheral, if the temperature of the fixing unit 19 detected by the temperature detection sensor 54 is lower than a predetermined temperature with respect to the removal of the UFP generated in the area where the fixing unit 19 is disposed by exhaust, the heater 52 The exhaust efficiency of the exhaust unit 61 is controlled in accordance with the time during which the heater 52 that heats the fixing unit 19 measured by the timer 23 is energized. In this case, when it is considered that the heater 52 is energized for a long time and the amount of UFP generated is relatively large, the exhaust efficiency of the exhaust unit 61 is increased. Specifically, a voltage is applied to the exhaust fan 63. By rotating the exhaust fan 63, exhaust when a large amount of UFP is generated can be efficiently performed. Further, when it is considered that the time for energizing the heater 52 is short and the amount of UFP generated is considered to be relatively small, the exhaust efficiency by the exhaust unit 61 is lowered, specifically, the exhaust fan 63 is not applied with a voltage and exhausted. By not rotating the fan 63, it is possible to prevent the temperature of the fixing unit 19 from being lowered due to the air flowing into the region where the fixing unit 10 is disposed by exhaust. Therefore, the digital multifunction peripheral 11 having such a configuration can perform efficient image formation. That is, image formation using energy efficiently can be performed.

  In this case, the exhaust unit 61 includes an exhaust fan 63 that rotates by application of a voltage. The control unit 12 controls the exhaust efficiency of the exhaust unit 61 by controlling the voltage applied to the exhaust fan 63. By doing so, it is possible to control the number of rotations of the exhaust fan 63 by controlling the application of voltage, and to perform efficient exhaust control.

  In this case, if the time measured by the timer 23 is longer than 3 minutes, the control unit 12 controls to increase the voltage applied to the exhaust fan 63. Then, it is possible to exhaust the UFP, which is expected to be generated more when the heating time is longer, to be more efficiently exhausted by increasing the rotational speed of the exhaust fan 63.

  This will be described with reference to Table 1. Table 1 shows the temperature (° C.) of the heat roller 51 when the digital multifunction peripheral 11 is started up, the voltage (V) applied to the exhaust fan 63, the detected number of UFPs (pieces) in 10 minutes, and per hour. It is a table | surface which shows the relationship with the detected value (mg) which detects VOC.

Here, the calculation method is shown for the numerical values shown in Table 1. First, FS-4300DN manufactured by Kyocera Document Solutions Co., Ltd. with a modified exhaust duct was installed as a digital multifunction device in a chamber made of SUS with a capacity of 5 m ³ . And it set to ventilate 83L / min. Printing was started after ventilation for a certain time. At the start of printing, the temperature of the surface of the heat roller was detected. And according to the detected temperature of the surface of the heat roller 51, the voltage supplied to the exhaust fan was sequentially changed. A printing operation was performed for 10 minutes, and UFP and volatile substances generated from the inside of the apparatus were sampled.

  In addition, about the volatile substance, it sampled on 100 ml (milliliter) / min conditions using the Tenax (Tenax) pipe | tube. Sampling was continued for about 1 hour after the digital multifunction peripheral was stopped. The sampled Tenax tube was desorbed with a heat desorption apparatus and measured by GC-MS to determine the amount of generation. The total amount of volatile organic compounds generated (Total VOC) was calculated by the calculation formula for the emission rate of Blue Angel Mark.

  Moreover, about UFP, it measured with the fine particle measuring device made from TSI (model FMPS3091), and detected UFP was computed by the calculation formula of the emission rate of a blue angel mark. The detected temperature (° C.) in Table 1 is the temperature detected by the temperature detection sensor, and indicates the temperature at the start of the digital multifunction peripheral. The applied voltage (V) indicates a voltage supplied to the exhaust fan. The UFP value (pieces) indicates the number measured per 10 minutes. The VOC value (mg (milligram)) indicates the weight measured per hour.

  Referring to Table 1, as shown in Sample 7, when the temperature detected by the heat roller is 23 ° C., the energization time is 3 minutes. If exhaust is not performed in such a situation, that is, if the exhaust fan is not rotated without supplying power to the exhaust fan, the UFP value is greatly increased as compared to the case shown in Sample 1. That is, a relatively large amount of UFP is generated, and it becomes necessary to collect this UFP. On the other hand, as shown in Sample 1, even when the temperature of the heat roller is 23 ° C. and the energization time is 3 minutes, if the exhaust is performed, that is, the voltage of 24V is supplied to the exhaust fan, If it is rotated, the UFP value does not rise so much. The same tendency is observed for VOC.

In Sample 2 and Sample 3, the temperature of the heat roller at the time of starting up the digital multi-function machine is 48 ° C. and 51 ° C., respectively, which are almost the same temperature. The energization time is also 3 minutes and 3 minutes, respectively. Here, for sample 2, the voltage applied to the exhaust fan is set to 24V, and for sample 3, the voltage applied to the exhaust fan is set to 16V, and the exhaust fan is rotated. The voltage applied to the exhaust fan in the case of sample 2 is 1.5 times the voltage applied to the exhaust fan in the case of sample 3. The temperature of the heat roller at the start of the digital multi-function peripheral is almost the same, the energization time is almost the same, and the detected UFP value is 1.5 times the voltage applied to the exhaust fan. In the case of sample 2, it is 0.9 × 10 ¹¹ pieces, and in the case of sample 3, it is 1.0 × 10 ¹¹ pieces. That is, the detected UFP value is almost the same between the case of sample 2 and the case of sample 3, although the voltage applied to the exhaust fan differs by about 1.5 times. Then, the voltage applied to the exhaust fan is 16V, and even if the applied voltage is increased to 24V and the exhaust efficiency is increased, the efficiency decreases.

Similarly, the case of sample 4, the case of sample 5 and the case of sample 6 will be described. The temperature of the heat roller at the start of the digital multifunction peripheral is 75 ° C., 78 ° C., and 80 ° C., respectively. is there. The energization times are 3 minutes, 3 minutes, and 3 minutes, respectively, and are the same. Here, for sample 4, the voltage applied to the exhaust fan is 24V, and for sample 5, the voltage applied to the exhaust fan is 16V, and the exhaust fan is rotated. For sample 6, no voltage is applied to the exhaust fan, and the exhaust fan is not rotated. The temperature of the heat roller at the start of the digital multifunction peripheral is almost the same, the energization time is almost the same, and the detected UFP value is the same as that of the sample 4 although the voltages applied to the exhaust fans are different. 0.8 × 10 ^{11 in} the case of sample 5, 0.9 × 10 ^{11 in} the case of sample 5, and 2.7 × 10 ^{11 in} the case of sample 6. That is, the detected UFP value is different even when the voltage is applied to the exhaust fan or the voltage applied to the exhaust fan is about 1.5 times different between the case of sample 4, the case of sample 5 and the case of sample 6. Are almost the same. Then, it is sufficient not to apply a voltage to the exhaust fan, and even if the applied voltage is increased to 16V and 24V to increase the exhaust efficiency, the efficiency is lowered.

  FIG. 7 is a graph showing the relationship between the amount of UFP generated and the elapsed time since the start of energization. In FIG. 7, the vertical axis represents the amount (number) of UFP generated, and the horizontal axis represents the elapsed time (minutes) after starting energization. A line 69a indicates a case where the temperature of the heat roller detected by the temperature detection sensor when the digital multifunction peripheral is activated is 42 ° C., and a line 69b indicates that the digital multifunction peripheral detected when the temperature detection sensor is activated. A case where the temperature of the heat roller is 35 ° C. is shown, and a line 69c shows a case where the temperature of the heat roller at the start-up of the digital multi-function peripheral detected by the temperature detection sensor is 23 ° C.

Referring to FIG. 7, as indicated by line 69 c, when the temperature of the heat roller is 23 ° C. and the energization time is 3 minutes, after about 8 to 9 minutes have elapsed since the start of energization, The number of UFPs has occurred up to a level exceeding 7.00 × 10 ⁴ . On the other hand, as shown by a line 69b, when the temperature of the heat roller is 35 ° C. and the energization time is 3 minutes, UFP is generated even after about 8 to 9 minutes have elapsed since the start of energization. The number is less than 5.00 × 10 ⁴ . Furthermore, as shown by the line 69a, when the temperature of the heat roller is 23 ° C. and the energization time is 3 minutes, it occurs even after about 8 to 9 minutes have passed since the energization was started. The maximum number of UFPs is about 4.00 × 10 ⁴ . That is, at any temperature, it reaches a peak in about 8 to 9 minutes and then decreases. From such experimental data, it can be considered that there is a correlation between the energization time, that is, the heating time of the fixing unit and the amount of UFP generated.

  The control unit 12 may be configured to control the power supplied to the exhaust fan to be higher if the temperature at the start-up of the digital multifunction peripheral 11 detected by the temperature detection sensor 54 is lower than a predetermined temperature. . Specifically, if the temperature of the heat roller 51 detected by the temperature detection sensor 54 is 23 ° C. or lower, the voltage applied to the exhaust fan 63 is controlled to be 24 V or higher.

  FIG. 8 is a flowchart showing the flow of processing in this case. Referring to FIG. 8, when the digital multi-function peripheral 11 is activated (S21) and a request for image formation is received (S22), the temperature detection sensor 54 detects the temperature of the heat roller 51 (S23). If the temperature of the heat roller 51 is 170 ° C. or higher, an image is formed as it is (S28), and the processing is terminated. On the other hand, if the temperature of the heat roller 51 is less than 170 ° C., the heater 52 is energized to heat the heat roller 51 (S25).

  Here, if the temperature of heat roller 51 detected by temperature detection sensor 54 is 23 ° C. or less (YES in S26), energization to heater 52 is started and a voltage of 24 V is applied to exhaust fan 63 ( S27). If the temperature of the heat roller 51 is higher than 23 ° C. (NO in S26), no voltage is applied to the exhaust fan 63 and only the heater 52 is energized. In this manner, the heat roller 51 is heated by energizing the heater 52 until the temperature of the heat roller 51 reaches 170 ° C. to form an image.

  With this configuration, the UFP, which is considered to be generated in large numbers due to the relatively low temperature of the fixing unit 19 at the start of the digital multifunction peripheral 11, rotates the exhaust fan 63 by applying a voltage to the exhaust fan 63. Thus, exhaust can be performed more efficiently.

  In addition, it is good also as a structure shown below. In other words, the exhaust unit 61 may include an air duct that communicates from the exhaust duct 62 to the outside of the digital multi-function peripheral 11. Further, the control unit 12 may control the air to be blown from the blower pipe to the exhaust duct 62.

  FIG. 9 is a schematic view showing a part of a digital multi-function peripheral provided with a blower tube. FIG. 9 corresponds to the cross section shown in FIG. In the digital multi-function peripheral 71 shown in FIG. 9, the same components as those of the digital multi-function peripheral 11 shown in FIG.

Referring to FIG. 9, a digital multi-function peripheral 71 according to still another embodiment of the present invention includes an exhaust unit 72 that exhausts an area where the fixing unit 19 is disposed. The exhaust unit 72 includes an exhaust duct 62, an exhaust fan 63, a filter 64, and a blower pipe 73 that communicates from the exhaust duct 62 to the outside of the digital multifunction peripheral 11. Then, the control unit 12 controls the exhaust efficiency of the exhaust unit 61 by blowing air from the blower pipe 73 to the exhaust duct 62. Specifically, when the exhaust fan 63 is rotated, air is sent from the blower pipe 73 to the exhaust duct 62 side. In this case, when the exhaust fan 63 is not rotating, the blower pipe 73 and the exhaust duct 62 are shut off, and when the exhaust fan 63 is rotated, the shutoff between the blower pipe 73 and the exhaust duct 62 is released. You may comprise. Also, the fan is not new illustrated in the blower tube 73 is provided to rotate the fan, and controls so as to capture air from the outside of actively digital MFP 71 in the direction indicated by the arrow D ₄ in FIG. 9 Also good.

  By comprising in this way, the air containing the UFP can be actively cooled using the air blown from the blower pipe 73, the generation of UFP can be reduced, and the exhaust to the outside of the apparatus is reduced. can do. In this case, almost no inflow of air to the fixing unit 19 occurs, so that the risk of a decrease in the temperature of the fixing unit 19 due to the inflow of air to the fixing unit 19 can be reduced.

  In addition, in said embodiment, although the exhaust part was set as the structure containing an exhaust duct, it is good not only as this but a structure which does not contain an exhaust duct. The exhaust fan may also be a member that sucks air in an area where the fixing unit is arranged by driving a motor or the like. The filter is also provided in the middle of the exhaust duct. However, the present invention is not limited to this, and the filter may be provided in the opening portion, or may be provided outside the digital multifunction peripheral.

  In the above embodiment, the cap portions are provided at both ends of the heat roller. However, the present invention is not limited to this, and a cap portion may be provided at least at one of the end portions. Moreover, it is good also as a structure which provides a cap part in the edge part at least any one side of a pressure roller.

  It should be understood that the embodiments and examples disclosed herein are illustrative in all respects and are not restrictive in any respect. The scope of the present invention is defined by the scope of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the scope of the claims.

  The image forming apparatus according to the present invention is particularly effectively used when efficient image formation is required.

  DESCRIPTION OF SYMBOLS 11,71 Digital compound machine, 12 Control part, 13 Operation part, 14 Image reading part, 15 Image formation part, 16 Hard disk, 17 Facsimile communication part, 18 Network interface part, 19 Fixing part, 21 Display screen, 22 ADF, 23 Timer, 24 Public line, 25 Network, 26a, 26b, 26c Computer, 27 Image forming system, 31, 32, 33 Paper cassette, 34 Paper, 35 Manual feed tray, 36 Paper discharge tray, 37 Visible image, 41 Photoconductor, 42 Charging unit, 43 Developer, 44 Transfer unit, 45 Cleaning unit, 46 Conveying belt, 47a, 47b, 47c, 47d, 47e Conveying roller, 48a, 48b, 48c, 48d, 48e Paper conveying path, 51 Heat roller, 52 Heater, 53 pressure low , 54 temperature detection sensor, 55 shaft center part, 56 elastic part, 57 surface layer part, 58a, 58b end part, 59a, 59b cap part, 60a, 60b bearing, 61, 72 exhaust part, 62 exhaust duct, 63 exhaust fan 64, 65, 66 opening, 69a, 69b, 69c line, 73 air duct.

Claims (6)

An image forming unit that forms a visible image with toner on paper;
A fixing unit for fixing the visible image formed by the image forming unit to the paper by heat;
A heating unit that generates heat when energized and heats the fixing unit;
A temperature detection unit for detecting the temperature of the fixing unit;
A time measuring unit for measuring the time for energizing the heating unit;
An exhaust unit for exhausting the area where the fixing unit is disposed;
If the temperature of the fixing unit detected by the temperature detection unit is lower than a predetermined temperature, energization to the heating unit is started, and the exhaust unit is activated according to the time to energize the heating unit by the time measurement unit. And an image forming apparatus. Including an exhaust fan that rotates upon application of voltage,
The image forming apparatus according to claim 1, wherein the control unit controls the voltage applied to the exhaust fan to be higher if the time measured by the time measurement unit is longer than a predetermined time. The exhaust unit is provided in an exhaust duct that communicates with the outside of the image forming apparatus from an area where the fixing unit is disposed, and an ultrafine contained in the air exhausted from the fixing unit. The image forming apparatus according to claim 1, further comprising an adsorption unit that adsorbs small particles. The fixing unit includes a pair of rollers heated by the heating unit, and a cap unit that covers at least one end of the pair of rollers. The image forming apparatus described. The image forming apparatus according to claim 4, wherein the cap portion is provided with an opening communicating with the exhaust duct. The exhaust unit includes a blower pipe communicating from the exhaust duct to the outside of the image forming apparatus,
The image forming apparatus according to claim 3, wherein the control unit blows air from the blower pipe to the exhaust duct to control the exhaust efficiency of the exhaust unit.

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