JP5981950B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  2. Description of the Related Art Conventionally, an electrophotographic image forming apparatus including a recovery device for recovering a volatile organic compound (VOC) containing a siloxane gas is known (for example, see Patent Document 1). This recovery device has an exhaust duct and a wire. One end of the exhaust duct is located in the vicinity of the fixing portion, which is a location where siloxane gas is easily generated in the image forming apparatus. The wire is disposed in the exhaust duct, and a high voltage is applied to the wire. When passing through the exhaust duct, the siloxane gas generated in the fixing unit adheres to the surface of the wire due to the dust collection effect of the wire to which a high voltage is applied. Thereby, the siloxane gas generated in the fixing unit is prevented from adhering to electronic devices and switches in the image forming apparatus.

JP 2012-53333 A

  However, the image forming apparatus disclosed in Patent Document 1 requires a dedicated power supply device for applying a high voltage to the wire. For this reason, there exists a problem that the cost of the whole apparatus increases. Further, in this image forming apparatus, there is a problem that the maintainability is poor because the entire wire needs to be replaced even when siloxane is deposited on only a part of the wire.

  The present invention has been made in view of such points, and the object of the present invention is to provide a volatile organic compound containing a siloxane gas generated in a fixing portion while realizing low cost and ensuring maintenance. It is to try to collect efficiently.

  An image forming apparatus according to the present invention includes a transfer unit that transfers a toner image to a sheet-like recording body, and a fixing unit that heats and fixes the toner image transferred to the recording body by the transfer unit to the recording body. A duct whose one end is located in the vicinity of the fixing unit, a blower fan for circulating air in the duct from one end side to the other end side, and provided in the duct so as to be separated from each other A driving unit configured to drive at least one of the first and second electrodes so that the first electrode and the second electrode configured and the contact and separation of the first and second electrodes are alternately performed; It has.

  According to the present invention, it is intended to efficiently recover a volatile organic compound containing a siloxane gas generated in a fixing unit while realizing cost reduction and ensuring maintenance.

FIG. 1 is a schematic diagram illustrating a laser printer as an image forming apparatus according to an embodiment. FIG. 2 is a schematic view showing a configuration in the exhaust duct. FIG. 3 is a schematic diagram showing the configuration of the siloxane gas recovery apparatus. FIG. 4 is a schematic view showing a test apparatus for confirming the effect of the siloxane gas recovery apparatus. FIG. 5 is a table showing the results of a siloxane recovery test.

Embodiment 1
FIG. 1 shows a laser printer 1 (hereinafter simply referred to as a printer) as an image forming apparatus 150 in the present embodiment. The printer 1 has an apparatus main body 60 having an image forming unit 20. A paper feed unit 10 is provided in the lower part of the apparatus main body 60, and a paper discharge unit 50 is formed on the upper surface of the apparatus main body 60. A plurality of transport roller pairs 11 to 13 that sandwich and transport the paper P (sheet-like recording body) are disposed in the paper transport path from the paper supply unit 10 to the paper discharge unit 50. In the following description, “left side” and “right side” mean the left side and right side of FIG. 1, respectively, and “front side” and “rear side” are the front side and the back side in the direction perpendicular to the paper surface of FIG. Means side.

  The paper feed unit 10 includes a paper feed cassette 10a in which sheet-like paper P is accommodated, and a pickup roller 10b for taking out the paper P in the paper feed cassette 10a and sending it out of the cassette. . The paper P sent out of the cassette from the paper feed cassette 10 a is supplied to the image forming unit 20 through the transport roller pair 11.

  The image forming unit 20 includes a photosensitive drum 21, a charger 23, an exposure device 25, a developing device 27, a transfer device 29, and a fixing device 40. At the time of image formation, first, the peripheral surface of the photosensitive drum 21 is charged by the charger 23, and thereafter, original image data (for example, image data of the original image received from the external terminal) is applied to the surface of the photosensitive drum 21 by the exposure device 25. ) Is applied. Thus, an electrostatic latent image corresponding to the image data is formed on the surface of the photosensitive drum 21. The electrostatic latent image formed on the surface of the photosensitive drum 21 is developed as a toner image by the developing device 27. As a result, a toner image is formed (carried) on the surface of the photosensitive drum 21. This toner image is transferred onto the paper P supplied from the paper supply unit 10 by the transfer device 29. The sheet P after the toner image is transferred is supplied to the fixing unit 40 by the rotation of the transfer roller in the transfer unit 29.

  The fixing device 40 includes a fixing roller 40a and a pressure roller 40b. A heating body is accommodated in the fixing roller 40a. The surface layer of the fixing roller 40a is made of, for example, silicon rubber. The pressure roller 40b is pressed against the fixing roller 40a by a biasing spring (not shown). The surface layer of the pressure roller 40b is made of, for example, silicon rubber. In the fixing device 40, the toner image is fixed on the paper P by heating and pressing the paper P supplied from the transfer device 29 between the fixing roller 40 a and the pressure roller 40 b. Then, the sheet P on which the toner image is fixed by the fixing device 40 is sent out to the downstream side in the sheet conveying direction by both rollers 40a and 40b. The paper P sent out from the fixing device 40 is discharged to the paper discharge unit 50 through a plurality of conveying roller pairs 12 and 13.

  Here, the surfaces of the fixing roller 40 a and the pressure roller 40 b become high when the toner image is fixed on the paper P. For this reason, the fixing device 40 generates a large amount of volatile organic compounds (VOC) containing a siloxane gas. The generated siloxane gas tends to adhere to surrounding members when the temperature is low, and thus adheres to an electric circuit or a relay contact, which causes a malfunction of the printer 1. In the present embodiment, in order to solve such a problem, a siloxane recovery device 100 for recovering the siloxane gas generated in the fixing device 40 is provided.

  As shown in FIG. 2, the siloxane collection device 100 includes an exhaust duct 101, a blower fan 102, a pair of collection filters 103 a and 103 b, and a collection main body 105.

  One end of the exhaust duct 101 is located in the vicinity of the fixing roller 40a. The other end of the exhaust duct 101 is connected to an exhaust port 60 a (see FIG. 1) formed in the right side wall portion of the apparatus main body 60.

  Specifically, the exhaust duct 101 has an air introduction part 101a, an air discharge part 101c, and an intermediate part 101b located between the two. The air introduction part 101a is formed so that a cross-sectional area decreases from the upstream side to the downstream side in the air flow direction. A part (or all) of the fixing roller 40a is located in the air introduction portion 101a. The intermediate portion 101b extends in the vertical direction, and a lower end portion thereof is connected to the air introduction portion 101a, and an upper end portion thereof is connected to the air discharge portion 101c. The blower fan 101 is accommodated in the intermediate portion 101b. By operating the blower fan 101, an air flow from one end side to the other end side is formed in the exhaust duct 101 (see the white arrow in FIG. 2). The air discharge portion 104 extends in the left-right direction, and a right end portion thereof is connected to the exhaust port 60a, and a left end portion thereof is connected to the intermediate portion 101b. The recovery filter 103a and the recovery filter 103b are attached to the left end (upstream end) and the right end (downstream end) of the air discharge unit 104, respectively. The recovery body 105 is provided between the left and right recovery filters 103a and 103b.

  The recovery filters 103a and 103b are filters that can adsorb a volatile organic compound (VOC) containing a siloxane gas present in the air. The recovery filters 103a and 103b are made of, for example, a flame retardant ozone VOC removal filter. For example, activated carbon particles impregnated with potassium carbonate are supported on the flame-retardant ozone VOC removal filter. If the openings of the filters 103a and 103b are too small, the flowability of the air passing through the exhaust duct 101 is deteriorated, and the temperature in the printer 1 is excessively increased. In the present embodiment, the openings of the filters 103a and 103b are sufficiently large in order to prevent such a temperature rise in the printer 1.

  The collection main body 105 includes a first electrode 106, a second electrode 107, a fixed plate 108, and a movable plate 109. The fixed plate 108 and the movable plate 109 are composed of vertical plates facing each other in the left-right direction. A plurality of first electrodes 106 and second electrodes 107 are provided. The first electrode 106 and the second electrode 107 are rod-shaped electrodes extending in the left-right direction. The base end portion of the first electrode 106 is fixed to the fixed plate 108. The first electrode 106 is connected to a power source 130 (see FIG. 3). The power source 130 is also used as a power source for the driving motor 125 of the fixing roller 40a. A base end portion of the second electrode 107 is fixed to the movable plate 109. The second electrode 107 is grounded via the movable plate 109.

  The fixed plate 108 is fixed to the wall surface of the exhaust duct 101. The movable plate 109 is configured to be movable in the left-right direction within the exhaust duct 101. The movable plate 109 is reciprocally driven left and right in synchronization with the rotation of the fixing roller 40a by a cam mechanism 120 described later. The movable plate 108 and the fixed plate 109 are preferably formed with a plurality of through holes so as not to disturb the air flow in the exhaust duct 101.

  As shown in FIG. 3, the cam mechanism 120 includes a rotating cam portion 121, a cam shaft portion 122 fixed to the rotating cam portion 121, a protruding rod 126 protruding from the right side surface of the movable plate 109, and a power transmission belt. 123. The movable plate 109 is urged to the right by the urging spring 110 so that the tip end portion of the protruding rod 126 is in contact with the outer peripheral surface (cam surface) of the rotating cam portion 121. The power transmission belt 123 is wound around the cam shaft portion 122 and the shaft portion 124 of the fixing roller 40a. Thus, the rotation of the fixing roller 40 a is transmitted to the rotating cam portion 121 via the power transmission belt 123. The rotating cam portion 121 is an eccentric cam having a minimum diameter portion and a maximum diameter portion. Then, when the rotating cam portion 121 rotates, the movable plate 109 reciprocates left and right, and the tip of each second electrode 107 is in contact with each first electrode at a predetermined cycle (a cycle determined by the cam shape of the rotating cam portion 121). The tip of 106 is contacted. When the second electrode 107 comes into contact with the first electrode 106, the circuit is temporarily short-circuited, and a large current flows through the contact portion between the electrodes 106 and 107 to generate a large Joule heat. As a result, the siloxane gas in the air is oxidatively decomposed and adheres to the contact portions of both electrodes 106 and 107. Thereby, the siloxane gas generated in the fixing device 40 can be efficiently recovered. Further, even when the siloxane gas recovery efficiency is lowered, the siloxane gas recovery efficiency can be recovered only by replacing the electrodes 106 and 107, and therefore, the maintenance performance is excellent.

  Further, since a plurality of the first electrodes 106 and the second electrodes 107 are provided, even if the contact portion of the pair of electrodes 106 and 107 is insulated by adhesion of siloxane, the non-insulated electrodes 106 and 107 cause siloxane. The gas can be recovered by oxidative decomposition.

  In addition, since the tips of both electrodes 106 and 107 are both formed in a sword mountain shape, Joule heat generated when the electrodes 106 and 107 are in contact can be increased as much as possible. As a result, the recovery efficiency of the siloxane gas can be increased.

  Further, in this embodiment, Joule heat is generated by bringing the first electrode 106 and the second electrode 107 into contact with each other, so that the power supply voltage is reduced as compared with the case where both electrodes are discharged in a non-contact state. It can be kept low. For this reason, it is possible to use the same power supply 130 as another actuator (for example, the driving motor 125 of the fixing roller 40a) without preparing a high-voltage power supply dedicated to the recovery device 100. As a result, the cost of the entire apparatus can be reduced.

  In the present embodiment, the cam mechanism 120 converts the rotation of the fixing roller 40a into the linear motion of the movable plate 109, so the drive source for the movable plate 109 and the drive source for the fixing roller 40a are shared. can do. Thereby, the cost of the entire apparatus can be reduced.

  In the present embodiment, the exhaust duct 101 is provided with recovery filters 103a and 103b that can adsorb a volatile organic compound containing a siloxane gas present in the air. Therefore, a volatile organic compound containing a siloxane gas that cannot be oxidized at the contact portion between both electrodes 106 and 107 can be recovered by both filters 103a and 103b. Therefore, the recovery efficiency of the siloxane gas can be increased as much as possible.

-Example-
Next, a test conducted to confirm the recovery effect of siloxane gas will be described. FIG. 4 shows a test apparatus 200 used for this test. The test apparatus 200 has a chamber 201 made of SUS. The volume of the chamber 201 is 5 m ³ . A TENAX tube 202 is connected to the side wall of the chamber 201. The TENAX tube 202 is an adsorption tube containing an activated carbon-based adsorbent (TENAX). The chamber 201 is connected to the suction pump 203 via the TENAX tube 202. In the chamber 201, an image forming apparatus 150 to be tested is installed. In the test, a composite machine KM-C3232 manufactured by Kyocera Corporation was used as the image forming apparatus 150. Then, the inside of the chamber 201 was ventilated at a rate of 15 m ³ / h by the suction pump 203, and continuous printing for 10 minutes was executed by the image forming apparatus 150 after 1 hour had elapsed since the start of ventilation. Meanwhile, a volatile substance containing siloxane gas generated from the image forming apparatus 150 was sampled by the TENAX tube 202 at a rate of 100 ml / min. Thereafter, sampling was continuously performed for about 20 minutes even after printing was stopped. Then, the TENAX tube 202 after sampling was desorbed with a heating device, and the amount of siloxane gas generated was measured by gas chromatography.

  FIG. 5 is a table summarizing the measurement results of siloxane gas. The image forming apparatus 150 according to the first exemplary embodiment includes a collection main body 105 and a pair of collection filters 103a and 103b, as in the above embodiment. The image forming apparatus 150 according to the second embodiment is different from the first embodiment in that the image forming apparatus 150 includes the collection main body 105 and the downstream (right side) collection filter 103b, but does not include the upstream collection filter 103a. Different. The image forming apparatus 150 in the comparative example does not include both the recovery main body 105 and the recovery filters 103a and 103b.

  From the test results of FIG. 5, it can be seen that the amount of siloxane generated decreases in the order of Comparative Example, Example 2, and Example 1. Thereby, the recovery effect of the siloxane gas by the first and second electrodes 106 and 107 and the recovery effect of the siloxane gas by the recovery filters 103a and 103b were verified.

<< Other embodiments >>
The present invention may be configured as follows. That is, in the above embodiment, a plurality of the first electrodes 106 and the second electrodes 107 are provided. However, the present invention is not limited to this, and only one first electrode 106 and two second electrodes 107 are provided. Also good.

  In the above embodiment, the first electrode 106 is a fixed electrode and the second electrode 107 is a movable electrode. However, the present invention is not limited to this. For example, the first electrode 106 may be a movable electrode and the second electrode 107 may be a fixed electrode. Alternatively, both electrodes 106 and 107 may be movable electrodes. In other words, any structure may be used as long as at least one of the first and second electrodes 106 and 107 is driven so that the contact and separation of the first and second electrodes 106 and 107 are alternately performed.

  In the above embodiment, the tip portions of both electrodes 106 and 107 are formed in a sword mountain shape. However, the present invention is not limited to this. For example, the electrodes 106 and 107 may be formed in a spherical shape or a flat shape.

  In the above embodiment, the laser printer 1 has been described as an example of the image forming apparatus 150, but the present invention is not limited to this. In other words, the image forming apparatus 150 may be a multifunction peripheral (MFP), for example.

  In the above embodiment, the paper P is described as a sheet-like recording material, but the present invention is not limited to this. That is, for example, an OHP sheet or the like may be used as the sheet-like recording material.

  As described above, the present invention is useful for an image forming apparatus, and particularly useful for an electrophotographic image forming apparatus provided with a fixing device.

P paper (sheet-shaped recording medium)
1 Printer (image forming device)
29 Transfer device (transfer section)
40 Fixing device (fixing part)
40a Fixing roller (heating roller)
40b Pressure roller 100 Recovery device 101 Exhaust duct (duct)
102 Blower fan 103 Recovery filter (filter)
105 Recovery Body 106 First Electrode 107 Second Electrode 120 Cam Mechanism (Driver)

Claims (4)

A transfer portion for transferring a toner image to a sheet-like recording material;
A fixing unit that heats and fixes the toner image transferred to the recording body by the transfer unit to the recording body;
A duct having one end positioned in the vicinity of the fixing unit;
A blower fan for circulating the air in the duct from one end side toward the other end side;
A first electrode and a second electrode provided in the duct and configured to be separable from each other;
An image forming apparatus comprising: a drive unit that drives at least one of the first and second electrodes so that the contact and separation of the first and second electrodes are alternately performed. The image forming apparatus according to claim 1.
An image forming apparatus, wherein a plurality of the first and second electrodes are provided. The image forming apparatus according to claim 1 or 2,
The fixing unit has a heating roller and a pressure roller, and is configured to fix the toner image on the recording body by heating and pressing the recording body between the rollers.
The image forming apparatus, wherein the driving unit is configured to convert the rotational motion of the heating roller into a linear motion and to contact the first and second electrodes at a predetermined cycle. The image forming apparatus according to any one of claims 1 to 3,
An image forming apparatus, wherein the duct is provided with a filter capable of adsorbing volatile organic compounds in the air.

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