JP6593026B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  2. Description of the Related Art Conventionally, image forming apparatuses such as copying machines and facsimiles employing an electrophotographic method have been widely used. In the image forming apparatus, there is a case where static electricity is generated on the paper due to friction at the time of transfer or fixing of the paper, conveyance, and the like. In such a case, the sheets may stick to each other when the sheets are stacked on the paper discharge tray and the subsequent work cannot be performed, or the sheets may stick to each other and the post-processing cannot be performed in the post-processing apparatus. There was a problem.

  Various techniques have been proposed to deal with these problems. For example, Patent Document 1 describes a static eliminator that controls a static eliminator based on information from an electrostatic sensor that detects the amount of static electricity on a sheet. Patent Document 2 describes an image forming apparatus that applies a correction voltage to a sheet to charge the sheet. Patent Document 3 describes an image recording apparatus that removes the charge of a sheet. Patent Document 4 describes an image forming apparatus including a first static eliminator and a second static eliminator.

JP 2009-1418 A JP 2013-227088 A Japanese Patent Laid-Open No. 10-181969 JP 2004-10240 A

  However, the image forming apparatuses described in Patent Documents 1 to 4 have the following problems. That is, in the image forming apparatuses of Patent Documents 1 to 4, when the neutralization device is controlled at a constant voltage, when the resistance value of the neutralization roller pair constituting the neutralization device increases, the current value decreases, and the neutralization performance of the neutralization device. There is a problem that will decrease. Specifically, for example, when the environmental temperature in which the image forming apparatus is installed is low, the charge removal roller pair of the charge removal apparatus is also brought into a low temperature state accordingly, and the charge removal performance of the charge removal apparatus is significantly reduced.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of preventing the charge removal performance of the charge removal unit from being deteriorated due to the environmental temperature of the apparatus.

In order to solve the above problems, an image forming apparatus according to the present invention is provided at a discharge port of an apparatus main body, and a discharge unit that discharges paper on which an image is formed via the discharge port, and a discharge port A blowing unit that blows air through the sheet discharging unit, and a discharging unit that is provided between the discharge unit and the blowing unit and discharges the sheet discharged to the discharging unit by constant voltage control. The temperature of the air blown from the blower is higher than the environmental temperature in the static eliminator and is lower than the melting temperature of the toner, and the blower is at least one of the winds blown to the paper discharger. The portion is applied to the static elimination unit.

  According to the present invention, since at least a part of the air blown to the paper discharge unit is applied to the static eliminator, the static eliminator can be maintained at a constant temperature, and the static eliminator performance of the static eliminator is maintained regardless of the environmental temperature. be able to.

1 is a diagram illustrating a configuration example of an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the structural example of a ventilation part and a static elimination unit. 2 is a block diagram illustrating an example of a functional configuration of the image forming apparatus. FIG. 6 is a flowchart illustrating an operation example of the image forming apparatus during printing.

  Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, the dimension ratio of drawing is expanded on account of description and may differ from an actual ratio.

[Configuration Example of Image Forming Apparatus 100]
FIG. 1 shows an example of the configuration of an image forming apparatus 100 according to the present invention. As shown in FIG. 1, the image forming apparatus 100 is called a tandem type image forming apparatus, and includes an automatic document feeder 80 and an apparatus main body 102. The automatic document conveying unit 80 is attached to the upper part of the apparatus main body 102 and sends out the paper set on the conveying table to the image reading unit 90 of the apparatus main body 102 by a conveying roller or the like.

  The apparatus main body 102 includes an operation display unit 70, an image reading unit 90, an image forming unit 10, an intermediate transfer belt 8, a paper feeding unit 20, a registration roller pair 32, a secondary transfer unit 34, and a fixing unit. 44, an automatic paper reversal conveyance unit 60 (Auto Duplex Unit: hereinafter referred to as ADU), a blower unit 300, and a static elimination unit 200.

  The operation display unit 70 includes a touch panel in which a display unit and an input unit are combined, and a plurality of operation keys including a start key and a determination key provided in a peripheral part of the touch panel. The operation display unit 70 displays an operation screen or the like on the screen, or forms an image such as a paper type, size, thickness (basis weight), or paper interval input by a touch operation or operation key operation on the operation screen. Accept conditions.

  The image reading unit 90 scans and exposes the document placed on the document table or the document transported by the automatic document transport unit 80 by the optical system of the scanning exposure device, and the image of the scanned document is CCD (Charge Coupled Device). ) Photoelectric conversion is performed by an image sensor to generate an image information signal. The image information signal is output to the image forming unit 10 after being subjected to analog processing, analog / digital (hereinafter referred to as A / D) conversion processing, pseudo correction, image compression processing, and the like by an image processing unit (not shown).

  The image forming unit 10 forms an image by electrophotography, and includes an image forming unit 10Y that forms a yellow (Y) image, an image forming unit 10M that forms a magenta (M) image, The image forming unit 10C forms a cyan (C) color image, and the image forming unit 10K forms a black (K) color image. In this example, common function names, for example, Y, M, C, and K indicating colors to be formed are added to the back of the reference numeral 10.

  The image forming unit 10Y includes a photosensitive drum 1Y, a charger 2Y, an exposure unit (optical writing unit) 3Y, a developing unit 4Y, and a cleaning unit 6Y arranged around the photosensitive drum 1Y. The image forming unit 10M includes a photosensitive drum 1M, a charger 2M, an exposure unit 3M, a developing unit 4M, and a cleaning unit 6M disposed around the photosensitive drum 1M. The image forming unit 10C includes a photosensitive drum 1C, and a charger 2C, an exposure unit 3C, a developing unit 4C, and a cleaning unit 6C disposed around the photosensitive drum 1C. The image forming unit 10K includes a photosensitive drum 1K, a charger 2K, an exposure unit 3K, a developing unit 4K, and a cleaning unit 6K disposed around the photosensitive drum 1K.

  Respective photosensitive drums (image carriers) 1Y, 1M, 1C, and 1K in the image forming units 10Y, 10M, 10C, and 10K, chargers 2Y, 2M, 2C, and 2K, exposure units 3Y, 3M, 3C, and 3K, development The devices 4Y, 4M, 4C, and 4K, the cleaning units 6Y, 6M, 6C, and 6K, and the primary transfer rollers 7Y, 7M, 7C, and 7K have a common configuration. In the following description, Y, M, C, and K are not used unless particularly distinguished.

  The charger 2 charges the surface of the photosensitive drum 1 almost uniformly. The exposure unit 3 is composed of, for example, an LPH (LED Print Head) having an LED array and an imaging lens, or a polygon mirror type laser exposure scanning device, and the photosensitive drum 1 is irradiated with laser light based on an image information signal. Scan to form an electrostatic latent image. The developing device 4 develops the electrostatic latent image formed on the photosensitive drum 1 with toner. As a result, a toner image which is a visible image is formed on the photosensitive drum 1.

  The intermediate transfer belt 8 is stretched by a plurality of rollers and is rotatably supported. Along with the rotation of the intermediate transfer belt 8, the primary transfer roller 7 and the photosensitive drum 1 rotate, and a predetermined voltage is applied between the primary transfer roller 7 and the photosensitive drum 1, whereby the photosensitive member. The toner image formed on the drum 1 is transferred onto the intermediate transfer belt 8 (primary transfer).

  The paper feed unit 20 has a plurality of paper feed trays 20A and 20B in which paper P such as A3 and A4 is accommodated. The paper P transported by the transport rollers 22, 24, 26, 28, etc. from the respective paper feed trays 20A, 20B is transported to the registration roller pair 32. Note that the number of paper feed trays is not limited to two. Further, a single or a plurality of large-capacity paper feeders that can accommodate a large-capacity paper P may be connected as necessary.

  The registration roller pair 32 corrects the bending of the paper P with respect to the paper conveyance direction D by forming a loop by abutting the leading edge of the paper P by the conveyance of the loop roller pair 30. The paper P in which the bending of the paper P is corrected is conveyed to the secondary transfer unit 34 at a predetermined timing. In the secondary transfer section 34, the Y, M, C, and K color toner images transferred onto the intermediate transfer belt 8 are collectively transferred onto the surface of the paper P conveyed by the resist roller pair 32 ( Secondary transfer). The second-transferred sheet P is conveyed to the fixing unit 44 on the downstream side in the sheet conveying direction D.

  The fixing unit 44 is disposed on the upstream side in the paper transport direction D with respect to the air blowing unit 300 and includes a pressure roller and a heating roller. The fixing unit 44 fixes the toner image on the surface of the paper P to the paper P by performing pressure and heat treatment on the paper P on which the toner image has been transferred by the secondary transfer unit 34.

  The transport path switching unit 48 performs switching control to switch the transport path of the paper P to the paper discharge path side or the ADU 60 side based on the selected print mode (single-sided print mode, double-sided print mode, etc.). The paper P on which single-sided printing has been completed in the single-sided printing mode or the paper P on which double-sided printing has been completed in the double-sided printing mode is discharged onto the paper discharge tray 112 by the paper discharge roller 46.

  Further, when an image is formed on the back side of the paper P in the duplex printing mode, the paper P on which the image is formed on the front side is transported to the ADU 60 via the transport roller 62 and the like. In the switchback path of the ADU 60, the reverse rotation control of the ADU roller 64 causes the rear end of the paper P to be transported to the U-turn path section, and is reversed by the transport rollers 66 and 68 provided in the U-turn path section. In this state, the paper is fed again to the secondary transfer unit 34.

  The air blowing unit 300 is disposed in the peripheral portion of the paper discharge roller 46 in the apparatus main body 102. The air blowing unit 300 applies wind to the surface of the paper P stacked on the paper discharge tray 112 and also applies at least a part of the wind to the static elimination unit 200.

  The neutralization unit 200 is attached to the side surface portion of the apparatus main body 102 between the air blowing unit 300 and the paper discharge tray 112. The neutralization unit 200 neutralizes the paper P discharged from the discharge port 110 by the paper discharge roller 46. The paper P on which the charge removal process has been performed is discharged onto the paper discharge tray 112. The paper discharge tray 112 may be attached to the static elimination unit 200 side, or may be attached to the apparatus main body 102 side. The neutralization unit 200 is an example of a neutralization unit in the present disclosure, and the paper discharge tray 112 is an example of a paper discharge unit in the present disclosure.

[Configuration example of the air blowing unit 300 and the static elimination unit 200]
FIG. 2 shows an example of a schematic configuration of the blower unit 300 and the charge removal unit 200. The blower unit 300 prevents tacking in the paper discharge tray 112 and prevents the static elimination performance of the static elimination unit 200 from being lowered. The blower unit 300 is located above the conveyance path R of the paper P and around the fixing unit 44 (in the vicinity). Has been placed. Here, tacking refers to a phenomenon in which sheets are stuck to each other by toner softened by heat of heat fixing when sheets P after heat fixing by the fixing unit 44 are sequentially stacked on the discharge tray 112. .

  The blower unit 300 includes a blower fan 310 and a duct 320. One end side of the duct 320 is attached to the blower fan 310, and the exhaust port 322 on the other end side of the duct 320 is configured to face the static elimination roller pair 210 of the static elimination unit 200. The blower fan 310 blows out the warmed air in the image forming apparatus 100 from the exhaust port 322 of the duct 320 to the neutralization unit 200 side through the discharge port 110 of the apparatus main body 102.

  The neutralization unit 200 includes a neutralization roller pair 210 and a temperature sensor 230. The neutralization roller pair 210 neutralizes the paper P by applying a predetermined voltage to the paper P on which the toner image is fixed. The neutralizing roller pair 210 is disposed in the housing 202 and includes rollers 212 and 214 disposed to face each other. The rollers 212 and 214 are made of, for example, conductive rubber rollers. In this example, for example, the surface of the paper P is neutralized by connecting the roller 212 to a voltage application unit (power supply unit) described later and grounding the roller 214. Alternatively, a voltage applying unit may be connected to both the rollers 212 and 214, and the sheet P may be neutralized by applying a voltage that cancels the charges on the upper and lower surfaces of the sheet P.

  The temperature sensor 230 is disposed in the vicinity of the static elimination roller pair 210 in the casing constituting the static elimination unit 200 and measures the temperature of the static elimination roller pair 210.

  When the blower fan 310 is turned on, wind is blown out from the exhaust port 322 of the blower fan 310. The wind blown from the exhaust port 322 of the blower fan 310 passes through the discharge port 110 of the apparatus main body 102, enters the neutralization unit 200, and strikes the neutralization roller pair 210. The air in the apparatus main body 102 is warmed by the warm-up operation of the fixing unit 44 or other image forming processing. Therefore, the static elimination roller pair 210 is also warmed. Thereby, even when environmental temperature is low and the static elimination roller pair 210 is a low temperature state, the temperature of the static elimination roller pair 210 can be hold | maintained more than fixed temperature. Further, the air blown from the blower fan 310 flows through the inside of the static elimination unit 200 and hits the paper P loaded on the paper discharge tray 112. As a result, the toner image on the surface of the paper P stacked on the paper discharge tray 112 after the start of the job can also be adjusted to a constant temperature.

[Block Configuration Example of Image Forming Apparatus 100]
FIG. 3 is a block diagram illustrating an example of a functional configuration of the image forming apparatus 100. As shown in FIG. 3, the image forming apparatus 100 includes an image reading unit 90, an image forming unit 10, a paper feeding unit 20, a fixing unit 44, an operation display unit 70, a storage unit 72, a communication unit 74, a static elimination unit 200, and a blower. The control part 50 which controls each operation | movement of the part 300 grade | etc., Is provided. The control unit 50 includes a CPU (Central Processing Unit) 52, a ROM (Read Only Memory) 54, and a RAM (Random Access Memory) 56. The CPU 52 reads out a program corresponding to the processing content from the ROM 54, develops it in the RAM 56, and executes it, thereby realizing functions related to image formation including static elimination processing.

  The storage unit 72 is configured by, for example, a nonvolatile semiconductor memory (so-called flash memory) or a hard disk drive. The storage unit 72 stores image forming condition information such as the thickness of the paper P and the paper type (smoothness).

  The static eliminator unit 200 includes a voltage application unit (power supply unit) 240, a crimping separation unit 220, and a temperature sensor 230. The voltage application unit 240 applies a predetermined voltage to the static elimination roller pair 210 under the control of the control unit 50. In the voltage control, constant voltage control is performed so that an equal charge can be applied regardless of the toner coverage on the paper P. The crimping separation unit 220 crimps or separates the static elimination roller pair 210 based on the drive signal supplied from the control unit 50. The temperature sensor 230 detects the temperature of the static elimination roller pair 210 and supplies a detection signal to the control unit 50.

  The air blower 300 has a fan drive motor 330. The fan drive motor 330 is driven based on a drive signal supplied from the control unit 50 to rotationally drive the blower fan 310. In this example, the fan drive motor 330 is driven in synchronization with the warm-up operation of the fixing unit 44 based on the control of the control unit 50.

  The communication unit 74 has various interfaces such as a network interface card (NIC), a modem-demodulator (MODEM), and a universal serial bus (USB). The control unit 50 transmits / receives various data to / from an external terminal device connected to a communication network such as a LAN (Local Area Network) or a WAN (Wide Area Network) via the communication unit 74. As a terminal device, a personal computer, a smart phone, a tablet computer etc. are mentioned, for example.

[Operation Example of Image Forming Apparatus 100]
FIG. 4 is a flowchart showing an example of the operation of the image forming apparatus 100 before the printing operation according to the present invention. The CPU 52 of the control unit 50 implements the processing shown in the flowchart of FIG. 4 by executing the software read from the ROM 54.

  In step S100, the image forming apparatus 100 is turned on by the user. The power-on of the image forming apparatus 100 includes returning from the low power mode or the sleep mode. When the image forming apparatus 100 is powered on, the process proceeds to step S110.

  In step S110, when the image forming apparatus 100 is turned on, the control unit 50 starts a warm-up operation of the fixing unit 44. Specifically, the control unit 50 turns on the heater that constitutes the fixing unit 44 to increase the temperature of the fixing belt, the fixing roller, and the like to the set fixing temperature. As the warming-up operation of the fixing unit 44 starts, the temperature in the image forming apparatus 100 also increases.

  In step S <b> 120, the control unit 50 turns on the blower fan 310 in synchronization with the warm-up operation of the fixing unit 44. The blower fan 310 blows (blows) the air in the image forming apparatus 100 warmed by the fixing unit 44 to the static elimination roller pair 210 and the paper discharge tray 112 installed outside the apparatus main body 102. Thereby, the static elimination roller pair 210 is warmed. Further, since the temperature of the blown air is lower than the temperature of the melted toner image, the toner image of the paper P on the paper discharge tray 112 is cooled.

  In step S130, the control unit 50 determines whether or not the temperature of the static eliminating roller pair 210 is within a set temperature range. The certain temperature range is a range that is lower than the toner melting temperature at which tacking occurs and exceeds the environmental temperature of the neutralizing roller pair 210 (when hot air is not blown). An example of the toner melting temperature is, for example, a paper temperature of about 70 ° C. The occurrence of tacking can be prevented by setting the static eliminating roller pair 210 to be lower than the toner melting temperature. In addition, by setting the static eliminating roller pair 210 to be higher than the environmental temperature, the temperature of the static eliminating roller pair 210 can be raised and the resistance value can be lowered. Note that a more optimal temperature range may be set within the above-described temperature range.

  When the controller 50 determines that the temperature of the static eliminating roller pair 210 is not within the set temperature range, the process proceeds to step S150. In step S150, the control unit 50 adjusts the temperature of the static eliminating roller pair 210 to be within the set range by controlling the air flow rate of the blower fan 310. For example, when the temperature of the static elimination roller pair 210 is equal to or lower than the environmental temperature, the control unit 50 sets the temperature of the static elimination roller pair 210 by increasing the air blowing amount of the blower fan 310 and increasing the temperature of the static elimination roller pair 210. Within range.

  On the other hand, when the control unit 50 determines in step S130 that the temperature of the static eliminating roller pair 210 is within the set temperature range, the process proceeds to step S140. In step S <b> 140, the control unit 50 performs control so as not to change the air flow rate while maintaining the air flow level (level) of the blower fan 310. In this way, the process of lowering the resistance value of the static eliminating roller pair 210 is performed before the start of printing (job).

  In step S160, the control unit 50 determines whether a print start command is output. For example, the print start command is output as a job from the computer 500 or is output by selecting a “start” button on the operation display unit 70. When determining that the print start command is not output, the control unit 50 waits until the print start command is acquired.

  On the other hand, if the control unit 50 determines in step S160 that a print start command has been output, the process proceeds to step S170. In step S170, the control unit 50 acquires paper information such as the paper type, size, thickness, and paper spacing of the paper P. The paper information is acquired from, for example, a job or by user input on the operation screen of the operation display unit 70. If the paper information is acquired, the process proceeds to step S180.

  In step S180, the control unit 50 determines whether or not the sheet P based on the acquired sheet information is a sheet P that has high smoothness and does not require neutralization. That is, it is determined whether the probability of occurrence of tacking is high and the probability of occurrence of electrostatic sticking between sheets is low. As an example of the paper P having a high smoothness, for example, coated paper can be cited. As an example of the paper P that does not need to be neutralized, for example, recycled paper, embossed paper, or the like having coarse eyes can be cited. If the control unit 50 determines that the sheet P based on the sheet information corresponds to the sheet P having high smoothness and which does not require neutralization, the process proceeds to step S190.

  In step S190, the control unit 50 controls the pressure-bonding / separating unit 220 to place the static eliminating roller pair 210 in the separated state. Thereby, the wind from the blower fan 310 passes between the static eliminating roller pairs 210 that are separated from each other, so that the wind for preventing tacking can be applied to the paper P on the paper discharge tray 112 more efficiently. If the static eliminating roller pair 210 is in the separated state, the process proceeds to step S230.

  On the other hand, when the control unit 50 determines in step S180 that the paper P based on the acquired paper information does not correspond to the paper P having high smoothness and which does not require neutralization, the process proceeds to step S200.

  In step S200, the control unit 50 determines whether the thickness of the sheet P based on the acquired sheet information is equal to or greater than a certain value (threshold value). If the control unit 50 determines that the thickness of the paper P is equal to or greater than a certain value, the control unit 50 proceeds to step S210. In step S210, the control unit 50 controls the pressure-bonding / separating unit 220 to place the neutralizing roller pair 210 in a separated state between sheets during printing. When the thickness of the sheet P is equal to or greater than a certain value, the heat of fixing is more easily taken away by the sheet than the sheet having the normal thickness. Therefore, in order to keep the fixing temperature of the fixing unit 44 constant, the sheet of the normal sheet type is used. The paper interval is set wider. Therefore, in this example, when there is a wide gap between the sheets, there is a slight margin between the sheets, so that the anti-tacking wind is efficiently blown to the discharge tray 112 by setting the neutralization roller pair 210 in a separated state. To do. If the control method of the static eliminating roller pair 210 is determined, the process proceeds to step S230.

  On the other hand, if the control unit 50 determines in step S220 that the thickness of the paper P is not equal to or greater than a certain value, the control unit 50 controls the pressure-bonding / separating unit 220 to bring the pair of static eliminating rollers 210 into a pressure-bonded state. For example, the sheet P needs to be neutralized and the space between the sheets is narrow. If the pressure-bonding state of the static eliminating roller pair 210 is maintained, the process proceeds to step S230.

  In step S230, the control unit 50 determines whether or not the static eliminating roller pair 210 is within a set temperature range. As described above, the certain temperature range is a range that is lower than the toner melting temperature at which tacking occurs and exceeds the environmental temperature of the static elimination roller pair 210 (when hot air is not blown).

  When the controller 50 determines that the static eliminating roller pair 210 is within the set temperature range, the process proceeds to step S240. In step S240, the control unit 50 performs control so as not to change the air flow rate while maintaining the air flow level of the blower fan 310.

  On the other hand, when the control unit 50 determines in step S230 that the static eliminating roller pair 210 is not within the set temperature range, the process proceeds to step S250. In step S250, the control unit 50 adjusts the temperature of the static eliminating roller pair 210 to be within the set range by controlling the air flow rate of the blower fan 310. For example, when the temperature of the static elimination roller pair 210 is equal to or lower than the environmental temperature, the control unit 50 sets the temperature of the static elimination roller pair 210 by increasing the air flow rate of the blower fan 310 and increasing the temperature of the static elimination roller pair 210. Within range.

  In step S260, when the static eliminating roller pair 210 is maintained at a constant temperature, the control unit 50 starts a printing operation based on the acquired job. In this example, such a series of processing is repeatedly executed.

  As described above, according to the present embodiment, since the blower fan 310 is driven to blow wind on the static elimination roller pair 210 of the static elimination unit 200 and the paper P on the paper discharge tray 112, the temperature of the static elimination roller pair 210 is reduced. The paper P on the paper discharge tray 112 can be maintained at a constant temperature. Thereby, tacking of the paper P on the paper discharge tray 112 can be prevented while preventing the static elimination performance from being lowered due to an increase in the resistance value of the static elimination roller pair 210.

  Moreover, although the static elimination roller pair 210 generally has a static elimination performance that deteriorates due to aging, according to the present embodiment, the temperature of the static elimination roller pair 210 is increased to increase the current value, so that the static elimination performance can be improved. it can. Thereby, the lifetime of the static elimination roller pair 210 can be improved. Further, the static elimination performance can be maintained regardless of the durability of the static elimination unit 200, and sticking of the paper P due to the electrostatic force can be suppressed.

  In addition, since the driving of the blower fan 310 is synchronized with the activation of the fixing unit 44, the air warmed in the apparatus main body 102 can be blown to the static elimination roller pair 210, and the static elimination roller pair 210 is more effectively avoided from the low temperature state. be able to. In addition, the neutralizing roller pair 210 can be preheated before passing. Further, according to the present embodiment, since the air blowing unit 300 is provided above the transport path R, it is possible to efficiently blow air on the image formed on the surface (upper surface) of the paper P.

  Furthermore, according to the present embodiment, when the paper P has high smoothness and does not require neutralization, the neutralization roller pair 210 is separated to send air to the paper P on the paper discharge tray 112 for tacking. Since prevention is given priority, the occurrence of tacking can be reliably avoided. Similarly, even when the thickness of the paper P is equal to or greater than a certain value, the static eliminating roller pair 210 is in the separated state, so that the tacking performance can be improved.

  It should be noted that the technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. For example, in the above-described embodiment, the image forming apparatus 100 forms a color image, but the present invention is not limited to an image forming apparatus that forms a color image, but an image forming apparatus that forms a monochrome image. Also good. Further, the charge removal unit 200 can be configured as a post-processing device, and can be configured as an image forming system by being connected to the downstream side of the image forming apparatus 100 in the sheet conveyance direction.

44 Fixing unit 50 Control unit 100 Image forming apparatus 112 Paper discharge tray (paper discharge unit)
200 Static elimination unit (static elimination unit)
210 Static elimination roller pair (roller)
220 Pressure separation / separation part 230 Temperature sensor 300 Blower part 310 Blower fan 320 Duct P Paper

Claims (6)

A paper discharge unit that is provided at a discharge port of the apparatus main body and that discharges paper on which an image is formed via the discharge port ;
A blower provided in the apparatus main body, for blowing wind through the discharge port to the paper discharged to the paper discharge unit;
A static elimination unit provided between the paper ejection unit and the blower unit, and neutralizing the paper ejected to the paper ejection unit by constant voltage control,
The temperature of the air blown from the blower unit is above the environmental temperature in the static eliminating unit and less than the melting temperature of the toner,
The image forming apparatus, wherein the blower unit applies at least a part of the air blown to the paper discharge unit to the charge removal unit. A pressure-bonding / separating part for pressure-bonding and separating a pair of rollers constituting the static elimination part;
A control unit that controls the pressure-bonding / separating unit so that the pair of rollers are in a separated state between the papers when the paper between the papers to be conveyed is wide;
The image forming apparatus according to claim 1, further comprising: A pressure-bonding / separating portion for pressure-bonding and separating a pair of rollers constituting the static elimination portion;
When the smoothness of the paper is high and there is no need for static elimination of the paper, a control unit that controls the pressure-bonding / separating unit so that the pair of rollers are in a separated state
The image forming apparatus according to claim 1, further comprising: A sensor for measuring the temperature of the static elimination unit;
A control unit that controls the amount of air blown from the blowing unit based on the measurement result measured by the sensor;
The image forming apparatus according to claim 1, further comprising: A fixing unit for fixing the image on the paper;
The blower is a upper side of the conveying path of the sheet, and, according to any one of claims 2 to 4, characterized in that disposed on the downstream side in the transport direction than the fixing portion Image forming apparatus. The image forming apparatus according to claim 5 , wherein the control unit operates the air blowing unit in synchronization with an operation of the fixing unit.

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