JP6627791B2 - Image forming device - Google Patents

Description

  The present invention relates to an image forming apparatus, and more particularly to a technique for suppressing emission of volatile ultrafine particles generated in a fixing unit and diffusing vapor generated from recording paper.

  2. Description of the Related Art An electrophotographic image forming apparatus forms a toner image by attaching toner to the surface of a recording sheet in an image forming section, and heats and presses the recording sheet in a fixing section to fix (fuse) the toner on the recording sheet. This forms an image on the recording paper. At this time, the temperature of the fixing unit is about 150 to 200 ° C.

  When the temperature of the fixing unit becomes high, volatile ultra-fine particles (UFP) such as low molecular siloxane are generated from the fixing roller and the resin around the fixing unit, and are discharged outside the machine. In recent environmental labels, regulations on the release of UFP have been tightened.

  A static eliminator (ionizer) is effective as one of the means for keeping the volatile ultrafine particles generated in the fixing unit inside the apparatus without discharging them to the outside of the apparatus. The ionizer generates a corona discharge at the tip of the discharge electrode needle by applying a high voltage to the discharge electrode needle, and electrically neutralizes the ultrafine particles with ionized air. Prevents release outside the aircraft.

  Japanese Patent Application Laid-Open Publication No. H11-163873 discloses a method in which a duct into which a diffused substance generated in a fixing unit flows is provided, an ionizer is disposed at a position away from the duct, an airflow is generated by a fan, and the diffused substance flows into the duct. And an image forming apparatus configured to merge ions generated by the ionizer.

JP 2013-195478 A

  By mounting an ionizer in an image forming apparatus as in Patent Document 1, volatile ultra-fine particles generated from a fixing unit can be kept inside the apparatus.

  Here, in the electrophotographic image forming apparatus, when the recording paper containing moisture is subjected to the fixing process in the fixing unit, if the temperature outside the apparatus is low, the moisture contained in the recording paper when the recording paper is heated is reduced. May change to steam. When the vapor rises from the image forming apparatus, the operator may misunderstand that an abnormality has occurred in the image forming apparatus. In this regard, by providing a fan that draws in air near the fixing unit as in Patent Literature 1, it is possible to diffuse steam generated from the recording paper and make the steam inconspicuous.

  However, mounting two ionizers and a fan on the image forming apparatus as in Patent Document 1 has a problem that the cost of the image forming apparatus is increased.

  The present invention has been made in view of the above circumstances, and suppresses the emission of volatile ultra-fine particles generated in a fixing unit and disperses vapor generated from recording paper by using an ionizer alone without providing a fan. The purpose is to:

  An image forming apparatus according to an aspect of the present invention includes an image forming unit that forms a toner image on a surface of a recording sheet, a heating roller and a pressure roller, and the recording sheet having the toner image formed on the surface. A fixing unit that nips the heating roller and the pressure roller to heat and press to fix the toner on the recording paper, a discharge electrode needle, and a high voltage power supply unit that generates a high voltage; An ionizer that applies a high voltage generated by the section to the discharge electrode needle to generate a corona discharge at the tip of the discharge electrode needle, and generates a direction of the needle tip of the discharge electrode needle with the corona discharge. A drive mechanism for performing an operation of switching between a first direction in which the ionic wind is applied to the heating roller and a second direction in which the ionic air is applied to the recording paper discharged from the fixing unit; And a control unit which controls the operation of Heather and the drive mechanism, but with the.

  According to the present invention, it is possible to suppress the emission of the volatile ultrafine particles generated in the fixing unit and to diffuse the vapor generated from the recording paper only by the ionizer without providing the fan.

FIG. 1 is a diagram illustrating a structure of an image forming apparatus according to an embodiment of the present disclosure. FIG. 2 is a functional block diagram illustrating an internal configuration of the image forming apparatus. FIG. 2 is a diagram showing a state in which a heating roller and a discharge electrode needle are visually recognized from above in FIG. 1, and showing an example of a shape of a discharge electrode needle of an ionizer. FIG. 4 is a diagram illustrating a configuration of a drive mechanism that drives a discharge electrode needle of the ionizer. It is a figure which shows another structure of the drive mechanism which drives the discharge electrode needle of an ionizer. It is a figure which shows the structure which branches an ion wind by a duct.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front sectional view showing a structure of an image forming apparatus according to an embodiment of the present invention.

The image forming apparatus 1 is, for example, a printer having both a scanner function and a copying function. The apparatus main body 11 includes a document reading unit 5, a paper feeding unit 14, an image forming unit 12, a fixing unit 13, and a top discharge tray 151. The paper feeding unit 14 is provided at the bottom of the apparatus main body 11 and includes a paper feeding cassette 141 for storing a plurality of recording papers P and a recording paper P stored in the paper feeding cassette 141 one by one. A recording paper pickup roller 142 for taking out the recording paper, and a paper feed roller pair 143 for sending out the recording paper P taken out by the recording paper pickup roller 142 to the transport path L1 are provided.

  The recording paper P fed by the feed roller pair 143 is sent out to the transport path L1 via the transport drum 171. The recording paper P sent to the transport path L1 is supplied to the image forming unit 12 by the registration roller pair 172.

  The image forming unit 12 is provided above the paper cassette 141 and includes a photosensitive drum 121, a charging device 122, an exposure device 123, a developing device 124, a transfer roller 125, and a cleaning device 60.

  The photoconductor drum 121 is an image carrier, and is configured to be rotatable about a rotation axis. The charging device 122 has a charging roller and charges the surface of the photoconductor drum 121. The exposure device 123 forms a latent image on the surface of the photosensitive drum 121 by irradiating a laser beam based on the image data of the document M read by the document reading unit 5.

  The developing device 124 has a developing roller 1241 and visualizes the latent image formed on the surface of the photosensitive drum 121 with toner. The transfer roller 125 transfers the toner image formed on the photosensitive drum 121 to the recording paper P in a transfer nip portion N1 formed between the transfer roller 125 and the photosensitive drum 121.

  The cleaning device 60 includes a cleaning roller and a cleaning blade. The cleaning roller and the cleaning blade come into contact with the surface of the photoconductor drum 121 to remove toner and extraneous matter remaining on the surface of the photoconductor drum 121 and clean the surface of the photoconductor drum 121.

  The fixing unit 13 fixes the toner image on the recording paper P by thermocompression bonding, and includes a heating roller 131 having a heat source 132 as a heat lamp, for example, and a pressure roller 133. The peripheral surface of the heating roller 131 is heated to about 150 to 200 ° C. by the heat source 132. The heating roller 131 and the pressure roller 133 form a pair, and when the recording paper P is nipped and conveyed by the heating roller 131 and the pressure roller 133 in the fixing nip portion N2, the unfixed toner image is heated by the heat source 132. And is fixed to the recording paper P by the pressure of the heating roller 131 and the pressure roller 133.

  A discharge electrode needle 71 of the ionizer 70 is arranged near the fixing unit 13. As will be described in detail later, when a high voltage is applied to the discharge electrode needle 71, the air at the needle tip is ionized to generate a weak ion wind, and the ions fall down to the fixing unit 13. Volatile ultra-fine particles such as low molecular siloxane generated from the high-temperature fixing unit 13 are electrically neutralized by ions released from the discharge electrode needle 71 and are retained inside the apparatus without being released outside the apparatus. .

  Next, the electrical configuration of the image forming apparatus 1 will be described. FIG. 2 is a functional block diagram illustrating an internal configuration of the image forming apparatus 1.

  The image forming apparatus 1 includes a control unit 10, an operation unit 47, a document feeding unit 6, a document reading unit 5, an image forming unit 12, a fixing unit 13, an ionizer 70, a driving mechanism 80, a thermistor 93, and the like.

  The document reading unit 5 includes a reading mechanism 163 (FIG. 1) having a light irradiation unit and a CCD sensor under the control of the control unit 10. The document reading section 5 irradiates the document with the light irradiating section, and receives the reflected light with a CCD sensor to read an image from the document.

  The operation unit 47 receives instructions from the operator regarding various operations and processes that can be executed by the image forming apparatus 1.

  The ionizer 70 includes a discharge electrode needle 71 and a high-voltage power supply unit 72.

  FIG. 3 is a diagram illustrating a state in which the heating roller 131 and the discharge electrode needle 71 are visually recognized from above in FIG. 1, and is a diagram illustrating a shape example of the discharge electrode needle 71 of the ionizer 70. As shown in FIG. 3, the discharge electrode needle 71 has a large number of needle-like protrusions projecting substantially perpendicular to the rotation axis A from a metal root member 71A extending along the rotation axis A of the heating roller 131 of the fixing unit 13. It is formed as a protrusion. The high-voltage power supply 72 generates, for example, an AC high-voltage of several thousand volts. The discharge electrode needle 71 is connected to a high-voltage power supply unit 72, and when a high voltage is applied from the high-voltage power supply unit 72, a corona discharge occurs at the tip of the discharge electrode needle 71.

  Returning to FIG. 2, the actuator 82 is one of the components of a drive mechanism 80 (FIG. 4) that drives the discharge electrode needle 71 of the ionizer 70 and switches the direction of the needle tip of the discharge electrode needle 71. The actuator 82 can be realized by, for example, a motor or a solenoid.

  FIG. 4 is a diagram illustrating a configuration of a drive mechanism 80 that drives the discharge electrode needle 71 of the ionizer 70. FIG. 4 is a view of the driving mechanism 80 viewed in the rotation axis direction of the heating roller 131 of the fixing unit 13. It is assumed that the recording paper P is conveyed from the right side in FIG. 4 to the fixing unit 13 and is discharged upward in FIG. 4 after the fixing process.

  The drive mechanism 80 includes a frame 81, an actuator 82, and a spring 83. The frame 81 is supported by a shaft 84 extending in parallel with the heating roller 131, and is swingable about the shaft 84. The discharge electrode needle 71 is attached to the end of the frame 81 on the fixing unit 13 side.

  An actuator 82 is connected to an end 85 of the frame 81 that is farther from the fixing unit 13. When the actuator 82 operates to reciprocate the end portion 85 in the vertical direction in FIG. 4, the frame 81 swings about the shaft 84. As a result, the direction of the needle tip of the discharge electrode needle 71 attached to the tip of the frame 81 is the direction D1 in which the ion wind 200 generated at the needle tip is applied to the heating roller 131, and the ion wind 200 is discharged from the fixing unit 13. The direction D2 is applied to the recording paper P. In FIG. 4, the discharge electrode needle 71 and the frame 81 when the tip of the discharge electrode needle 71 is oriented in the direction D2 are drawn by dashed lines.

  A spring 83 is connected to an end 86 of the frame 81 near the fixing unit 13. The spring 83 is, for example, a pulling spring, and maintains the frame 81 in a posture in which the tip of the discharge electrode needle 71 faces the direction D1 by urging the end portion 86 in the direction of arrow A shown in FIG. Therefore, when the actuator 82 is not operating, the frame 81 is drawn by a solid line in FIG.

  According to the operation control of the drive mechanism 80 by the control unit 100, when the actuator 82 does not pull down the end 85 of the frame 81, the tip of the discharge electrode needle 71 is in the direction D1. At this time, the ion wind 200 generated at the tip of the discharge electrode needle 71 hits the heating roller 131, and the volatile ultrafine particles generated from the high-temperature heating roller 131 are electrically neutralized by the ion wind 200. You. Thereby, the ultrafine particles are retained inside the machine without being released outside the machine.

  On the other hand, under the control of the operation of the drive mechanism 80 by the control unit 100, the actuator 82 pulls down the end portion 85 of the frame 81, and the tip of the discharge electrode needle 71 moves against the urging force of the spring 83 to move in the direction D2. In this case, the ion wind 200 is applied to the vapor rising from the recording paper P heated by the fixing process, and the vapor is diffused. This makes it possible to make the steam inconspicuous and prevent the operator from misunderstanding that the image forming apparatus 1 is abnormal.

  The thermistor 93 is disposed on an outer wall or the like of the apparatus main body 11 and measures the temperature outside the apparatus.

  The control unit 10 includes a processor, a RAM, a ROM, a dedicated hardware circuit, and the like. The processor is, for example, a CPU, an MPU, an ASIC, or the like. The control unit 10 includes a control unit 100. The control unit 10 functions as the control unit 100 when the processor operates according to a control program stored in a memory built in the control unit 10, for example.

  The control unit 100 controls the overall operation of the image forming apparatus 1. The control unit 100 is connected to the document reading unit 5, the document feeding unit 6, the image forming unit 12, the fixing unit 13, the operation unit 47, the high-voltage power supply unit 72, the driving mechanism 80, the actuator 82, the thermistor 93, and the like. I have. The control unit 100 controls the above-described mechanisms connected to each other and transmits and receives signals or data to and from each mechanism.

  Specifically, the control unit 100 issues an instruction to the high voltage power supply unit 72 to generate a high voltage in accordance with causing the fixing unit 13 to perform the fixing process. That is, the ionizer 70 operates when the fixing unit 13 is performing the fixing process. The main role of the ionizer 70 is to electrically neutralize volatile ultra-fine particles generated from the high-temperature fixing unit 13 and keep it inside the apparatus. Therefore, when no ultrafine particles are generated, that is, when the fixing unit 13 is not performing the fixing process, the ionizer 70 does not need to operate. Therefore, the control unit 100 does not always operate the ionizer 70 but operates the ionizer 70 when the fixing unit 13 is performing the fixing process. Thus, power consumption can be reduced.

  Further, the control unit 100 issues an instruction to the actuator 82 to operate the actuator 82. At this time, the control unit 100 determines that the outside temperature measured by the thermistor 93 while the fixing unit 13 is operating is equal to the first threshold value (experiment, etc., as it is difficult to generate steam in an environment where the fixing unit 13 is operating). When the temperature is equal to or higher than the predetermined external temperature, the actuator 82 is operated so that the tip of the discharge electrode needle 71 is directed in the direction D1.

  On the other hand, when the fixing unit 13 is operating and the outside temperature measured by the thermistor 93 is lower than the first threshold value, the control unit 100 controls the discharge electrode needle 71 so that the needle tip of the discharge electrode needle 71 faces the direction D2. The actuator 82 is operated. Thereby, when the temperature outside the apparatus is high, that is, when the vapor is hardly emitted from the recording paper P, the ionizer 70 is used for neutralizing the volatile ultra-fine particles generated from the fixing unit 13 and the temperature outside the apparatus is reduced. When the temperature is low, that is, when the vapor is easily emitted from the recording paper P, the vapor can be diffused by using the ion wind 200 generated from the tip of the discharge electrode needle 71.

  Further, the control unit 100 moves the tip of the discharge electrode needle 71 in the direction D1 (i) when the outside temperature measured by the thermistor 93 is equal to or higher than the first threshold while the fixing unit 13 is operating. (Ii) When the fixing unit 13 is operating and the outside temperature measured by the thermistor 93 is lower than the first threshold (a second threshold value (e.g., steam in an environment where the fixing unit 13 is operating) When it is higher than the first threshold value and lower than the above-described first threshold value, the tip of the discharge electrode needle 71 is directed to a position between the direction D1 and the direction D2. (Iii) When the fixing unit 13 is operating and the outside temperature measured by the thermistor 93 is equal to or lower than the second threshold, the tip of the discharge electrode needle 71 is oriented in the direction D2. Multiple tip of discharge electrode needle 71 according to outside temperature It may be changed to the floor.

  Further, the control unit 100 controls the actuator so that the tip of the discharge electrode needle 71 is oriented in the direction D1 when the recording paper P is not passed through the nip between the heating roller 131 and the pressure roller 133 of the fixing unit 13. When the recording paper P is passed through the nip, the actuator 82 may be operated such that the tip of the discharge electrode needle 71 is directed to the direction D2. Thus, the steam can be diffused by generating the ion wind 200 toward the transport path of the recording paper P in which the steam is easily generated.

  Further, when the fixing unit 13 is in operation and the outside temperature measured by the thermistor 93 is lower than the threshold value, the control unit 100 controls the discharge electrode every time a plurality of recording papers P are discharged from the fixing unit 13. The actuator 82 may be operated so that the direction of the needle tip of the needle 71 is alternately switched between the direction D1 and the direction D2. Thus, the vapor generated from the recording paper P can be diffused while the volatile ultra-fine particles generated from the fixing unit 13 are kept inside the apparatus.

  As described above, according to the present embodiment, by utilizing the ionic wind 200 generated from the tip of the discharge electrode needle 71, the super-volatile property generated in the fixing unit 13 by the ionizer 70 alone without a fan is provided. The release of the fine particles can be suppressed, and the vapor generated from the recording paper P can be diffused.

  Note that the present invention is not limited to the configuration of the above embodiment, and various modifications are possible. For example, it can be modified as follows.

  FIG. 5 is a diagram showing another configuration of a drive mechanism for driving the discharge electrode needle 71 of the ionizer 70. The configuration shown in FIG. 5 is obtained by replacing the actuator 82 in the configuration shown in FIG. 4 with a different mechanical configuration. Otherwise, the configuration is the same as that of FIG.

  The actuator 82A can be realized by, for example, a cam, a ratchet gear, or the like. The actuator 82A rotationally moves by obtaining a driving force from a drive motor (not shown) that rotationally drives the heating roller 131 and the pressure roller 133. That is, the actuator 82 </ b> A operates in conjunction with the rotation of the heating roller 131 and the pressure roller 133. Also in this configuration, the control unit 100 controls the driving of the driving motor, whereby the frame 81 swings while the fixing unit 13 is operating, and the direction of the tip of the discharge electrode needle 71 is changed to the direction D1. And the direction D2. Thereby, the vapor generated from the recording paper P is diffused while the volatile ultra-fine particles generated from the fixing unit 13 are kept inside the apparatus.

  Still another embodiment will be described. FIG. 6 is a diagram illustrating a configuration in which an ion wind is branched by a duct. In the configuration shown in FIG. 6, unlike the configurations shown in FIGS. 4 and 5, a duct 300 is provided instead of the driving mechanism 80. The duct 300 has three openings 300A, 300B, and 300C. The opening 300A is at the tip of the discharge electrode needle 71, the opening 300B is near the heating roller 131, and the opening 300C is the recording paper of the fixing unit 13. Each is open downstream in the discharge direction. The ion wind 200 generated at the tip of the discharge electrode needle 71 flows in from the opening 300A, branches inside the duct 300, and flows out from the openings 300B and 300C. Thus, the vapor generated from the recording paper P can be diffused while the volatile ultra-fine particles generated from the fixing unit 13 are kept inside the apparatus.

Reference Signs List 1 image forming apparatus 12 image forming unit 13 fixing unit 131 heating roller 133 pressing roller 70 ionizer 71 discharge electrode needle 72 high voltage power supply unit 80 driving mechanism 81 frame 82 actuator 82A actuator 83 spring 93 thermistor 200 ion wind 300 duct D1 first Direction D2 Second direction P Recording paper

Claims (7)

An image forming unit that forms a toner image on the surface of the recording paper;
A fixing unit that includes a heating roller and a pressure roller, and nips the recording paper having the toner image formed on its surface with the heating roller and the pressure roller to heat and press to fix the toner on the recording paper When,
A discharge electrode needle, and a high-voltage power supply unit for generating a high-voltage voltage, wherein a high-voltage generated by the high-voltage power supply unit is applied to the discharge electrode needle to generate corona discharge at the tip of the discharge electrode needle. With an ionizer,
The direction of the tip of the discharge electrode needle is set to a first direction in which ion wind generated due to the corona discharge is applied to the heating roller, and a second direction in which the ion wind is applied to recording paper discharged from the fixing unit. A drive mechanism that performs an operation of switching between the directions of
An image forming apparatus comprising: a control unit that controls operation of the ionizer and the driving mechanism.   The control unit controls the operation of the driving mechanism, and when the recording paper is not passed through the nip portion between the heating roller and the pressure roller of the fixing unit, the tip of the discharge electrode needle is The image forming apparatus according to claim 1, wherein the direction is the first direction, and the tip of the discharge electrode needle is the second direction when the recording paper is passed through the nip portion. It further includes a thermistor that measures the temperature outside the machine,
The control unit includes:
The ionizer is driven when a fixing process is being performed in the fixing unit,
Controlling the driving mechanism to move the tip of the discharge electrode needle in the first direction when the fixing unit is operating and the outside temperature measured by the thermistor is equal to or higher than a first threshold. When the fixing unit is operating and the outside temperature measured by the thermistor is lower than the first threshold, the tip of the discharge electrode needle is oriented in the second direction. The image forming apparatus according to claim 1. It further includes a thermistor that measures the temperature outside the machine,
The control unit includes:
The ionizer is driven when a fixing process is being performed in the fixing unit,
Controlling the driving mechanism to move the tip of the discharge electrode needle in the first direction when the fixing unit is operating and the outside temperature measured by the thermistor is equal to or higher than a first threshold. To
When the fixing unit is operating and the outside temperature measured by the thermistor is higher than a second threshold lower than the first threshold and lower than the first threshold, the discharge electrode needle To a position between the first direction and the second direction,
2. The tip of the discharge electrode needle is directed in the second direction when the fixing unit is operating and the outside temperature measured by the thermistor is equal to or less than the second threshold. Image forming apparatus. It further includes a thermistor that measures the temperature outside the machine,
The control unit, the drive mechanism, wherein when the temperature of the fixing portion is measured by operating in and the thermistor outside is lower than the threshold value, each time the recording sheet from said fixing portion is a plurality discharged to the discharge needle electrode needle tip orientation of that to switch alternately in the first direction and the second direction, claims to direct the needle tip of the discharge electrode needle in the second direction 1 An image forming apparatus according to claim 1. The drive mechanism includes a frame to which the discharge electrode needle is attached at a distal end and which is pivotally supported, an actuator connected to a first end of the frame and configured to swing the frame, and a second part of the frame. 6. The image forming apparatus according to claim 1, further comprising a spring connected to an end and maintaining the frame in a posture in which a tip of the discharge electrode needle faces the first direction. 7. An image forming unit that forms a toner image on the surface of the recording paper;
A fixing unit that includes a heating roller and a pressure roller, and nips the recording paper having the toner image formed on its surface with the heating roller and the pressure roller to heat and press to fix the toner on the recording paper When,
An ionizer having a discharge electrode needle and a high-voltage power supply unit for generating a high-voltage voltage, and applying a high-voltage generated by the high-voltage power supply unit to the discharge electrode needle to generate a corona discharge at the tip of the discharge electrode needle. ,
An image forming apparatus comprising: a duct that guides the ionic wind accompanying the corona discharge to each of the heating roller and a downstream side of the fixing unit in a recording paper discharging direction.