JP2018060113A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which: a reduction in UFPs and a VOC by reducing the number of revolution of an exhaust fan requires limitation of paper type and reduces productivity; and a structure sucking again an exhausted air requires a space to be incorporated in a short section from a miniaturized fixing device to a sheet ejection port.SOLUTION: The above-described problem is solved by an image forming apparatus according to the present invention. In summary, the present invention comprises: image forming means that forms a toner image on a recording material S by using a toner containing a mold release agent; fixing means that thermally fixes the toner image formed on the recording material S by the image forming means; and an exhaust path that is provided substantially immediately above the fixing means and in which air in the vicinity of the fixing means flows. The exhaust path is partially formed of an upper exterior cover part of an apparatus body.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a printing machine.

  It is known that ultra fine particles (Ultra Fine Particle (UFP): particles of several nm to several hundred nm) and VOC can be generated in a fixing device maintained at a high temperature in an image forming apparatus. ing. UFP is considered to be caused by a release agent (wax) contained in the toner particles in order to improve the releasability of the toner from the fixing member. That is, when the toner image is heat-fixed, it is considered that the wax is vaporized and becomes a mist (vapor), which is UFP. In recent years, there has been a growing demand for maintenance of indoor air environments, and reduction of UFP and VOC has been demanded.

  In contrast to suppressing the above-described UFP and VOC emission, Patent Document 1 proposes a filter that increases the collection efficiency with a filter by reducing the rotational speed of the exhaust FAN. Patent Document 2 proposes a configuration in which part of the air discharged outside the apparatus is sucked again and re-discharged through a filter.

JP 2010-117421 A JP 2006-119469 A

  However, the reduction by reducing the rotation speed of the exhaust FAN requires a limitation of the paper type and the like, and a reduction in productivity becomes a problem. Further, in the configuration in which the discharged air is re-sucked, there is a problem of a space to be incorporated in a short section from the miniaturized fixing device to the sheet discharge port.

  The solution to the above problem is achieved by the image forming apparatus according to the present invention. In summary, the present invention relates to an image forming unit that forms a toner image on the recording material S using toner containing a release agent, and heat fixing the toner image formed on the recording material S by the image forming unit. A fixing means (158) for performing the operation, and an exhaust passage (11) through which the air in the vicinity of the fixing means (158) flows in the vicinity of and substantially immediately above the fixing means (158), and a part of the exhaust passage (11) is a device. It is formed by the upper exterior cover part (1) of the main body (101).

  According to the present invention, the exhaust path that also serves as the outer cover of the apparatus main body is provided immediately above the vicinity of the fixing device, and the entire width direction of the apparatus main body can be used as the exhaust path while maintaining the miniaturization of the apparatus main body. Therefore, it is possible to efficiently suck and collect UFP and the like generated in the high-temperature fixing unit.

1 is a cross-sectional view of an image forming apparatus in an embodiment of the present invention. It is a perspective view in Example 1 of this invention. It is sectional drawing from the apparatus main body front in Example 1 of this invention. It is sectional drawing from the apparatus main body right side in Example 1 of this invention.

[Example 1]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the operation of the electrophotographic image forming apparatus will be described with reference to FIGS. An image forming apparatus 101 is an external view and a cross-sectional view of a so-called intermediate transfer tandem type image forming apparatus in which four color image forming units are arranged side by side on an intermediate transfer belt.

<Image creation process>
An image forming process up to the secondary transfer portion will be described. In this embodiment, an image forming unit 110Y that forms an image with yellow (Y) toner, an image forming unit 110M that forms an image with magenta (M) toner, and an image formation that forms an image with cyan (C) toner. 110C and an image forming unit 110BK that forms an image with black (BK) toner. Since the image forming unit 110Y, the image forming unit 110M, the image forming unit 110C, and the image forming unit 110BK have the same configuration except for the color of the toner, the image forming unit 110Y will be described as a representative.

  The image forming unit 110Y as a toner image forming unit includes a photoconductor 111 as an image carrier, a charger 112 for charging the photoconductor 111, an exposure unit 113, a developing device 114, a primary transfer member 115, and a photoconductor cleaner 116. Composed. The surface of the photoconductor 111 rotating in the direction of the arrow m in the figure is uniformly charged by the charger 112. Laser light modulated in accordance with an image signal is output from a scanner unit 117 including a laser and a polygon mirror correction system lens, and this laser light is reflected by a folding mirror, and the photosensitive member 111 charged by the exposure unit 113 is exposed. As a result, an electrostatic latent image is formed.

  The electrostatic latent image formed on the photoconductor 111 is developed by the developing device 114, and a toner image is formed on the photoconductor. Thereafter, a yellow toner image is transferred onto the intermediate transfer belt 1 as a belt member by the primary transfer member 115 with a predetermined pressure and primary transfer bias. Thereafter, the untransferred toner remaining on the photoconductor 111 is collected by the photoconductor cleaner 116 and prepared for the next image formation again.

  In the case of FIG. 1, the image forming unit 110 described above has four sets of yellow (Y), magenta (M), cyan (C), and black (Bk). Therefore, the magenta toner image formed by the image forming unit M is transferred to the intermediate transfer belt 120 with respect to the yellow toner image formed on the intermediate transfer belt 120. Further, the cyan toner image formed in the image forming portion C is transferred to the intermediate transfer belt 120 with respect to the formed magenta toner image. Further, the black toner image formed by the image forming unit BK is transferred to the intermediate transfer belt 120 with respect to the cyan toner image.

  In this way, the toner images of different colors are formed on the intermediate transfer belt 120 so as to overlap each other, so that a full color image is formed on the intermediate transfer belt 120. Although the number of colors in this embodiment is four, the number of colors is not limited to four, and the order of colors is not limited to this.

  The image forming process of each color processed in parallel by each of the image forming units 110Y, 110M, 110C, and 110BK described above is performed at the timing of superimposing on the upstream color toner image that is primarily transferred onto the intermediate transfer belt 120. As a result, a full-color toner image is finally formed on the intermediate transfer belt 120 and conveyed to the secondary transfer unit.

<Transfer material transfer process>
The recording material S is stored so as to be stacked on the lift-up device 152 in the recording material storage unit 151, and is fed by the paper feed roller 153 at the timing of image formation. Of course, other paper feeding methods may be used. The recording material S delivered by the paper feed roller 153 passes through the paper feed conveyance path 154 and is conveyed to the registration roller 155. After the skew correction and timing correction are performed in the registration roller 155, the recording material S is sent to the secondary transfer portion.

  The secondary transfer portion is a transfer nip portion formed by the opposing secondary transfer driving roller 121 that is the first secondary transfer member and the secondary transfer outer roller 156 that is the second secondary transfer member. The toner image on the intermediate transfer belt is transferred onto the recording material S by applying a predetermined pressure and a secondary transfer bias. If a gap is generated between the secondary transfer outer roller 156, the recording material S, and the intermediate transfer belt 120 in the upstream portion of the transfer nip, the secondary transfer bias may be abnormally discharged in the gap portion. The material S is sent to the transfer nip portion in close contact with the intermediate transfer belt.

<Process after secondary transfer>
As described above, the full color toner image formed on the intermediate transfer belt 120 in the secondary transfer portion is secondarily transferred onto the recording material S by the conveyance process and the image forming process of the recording material S described above. Thereafter, the recording material S is transported to the fixing device 158 by the pre-fixing transport unit 157. The fixing device 158 has various configurations and methods. In FIG. 1, a toner image is formed on the recording material S by applying a predetermined pressure and heat in a fixing nip formed by the opposing fixing roller 159 and pressure roller 160. Is melt-fixed.

  Here, the fixing roller 159 includes a heater serving as a heat source, and the pressure roller is urged toward the fixing roller 159. The recording material S that has passed through the fixing device 158 is conveyed to the paper discharge roller 161 and is directly discharged onto the paper discharge tray 165, or when double-sided image formation is required, the recording material S is guided to the branch device 163 and switched by the reverse roller 161. By performing the back operation, the leading and trailing ends are switched, and a route selection as to whether the sheet is conveyed to the duplex conveying device 164 is performed.

  Thereafter, the recording paper of the subsequent job conveyed from the paper feed roller 153 is synchronized with the recording material of the subsequent job, and the paper is fed from the re-feed path 166 to the paper feed path 154 and similarly sent to the secondary transfer unit. The image forming process on the back surface (second surface) is the same as that of the above-described front surface (first surface), and thus description thereof is omitted.

<UFP measures>
FIG. 2 is a perspective view of the state in which the exterior upper cover 1 is removed from the image forming apparatus main body, as viewed from the upper left front side. FIG. 3 is a cross-sectional view of the main body 101 viewed from the front. Further, FIG. 4 shows a cross-sectional view of the main body 101 viewed from the right side. As shown in FIGS. 2 to 4, an air inlet 12 that sucks air is provided immediately above the vicinity of the fixing device 158. The intake port 12 is provided in the upper part of the upstream side of the discharge roller 161 and substantially in the entire area of the recording material S passing area perpendicular to the conveying direction of the recording material S, so that the fixing device 158 sucks most of the generated air. be able to.

  An exhaust duct 11 that also serves as an outer cover 1 of the apparatus main body 101 that discharges air to the outside of the apparatus is provided above the intake opening 12, and the fan 13 is located in the exhaust duct 11 closest to the back of the apparatus main body 101. Is provided.

  Thereby, the air sucked from the suction port 12 is less likely to flow back into the conveyance path, and the fan 13 can be sucked efficiently near the suction port 12. Through the exhaust duct 11, the fan 13 blows air from the inlet 12 toward the back side of the apparatus main body 101, passes through substantially the entire width direction of the apparatus main body 101, and is exhausted to the outside of the apparatus main body 101. Further, on the downstream side of the fan 13 in the exhaust duct 11, filter 14 means for collecting fine particles in the exhaust is disposed.

  Hot air generated in the vicinity of the fixing device 158 is sucked into the discharge duct 11 by the rising airflow and the suction force of the fan 13. Further, the guide member from the fixing device 158 to the discharge roller 161 is configured not to have a vent other than the vicinity of the discharge roller 161, and the static pressure is increased with respect to the air flow toward the discharge roller 161. For this reason, most of the air near the fixing device 158 is sucked into the exhaust duct 11.

  In this way, the UFP generated in the vicinity of the fixing device 158 is collected by the fan 13 that is discharged outside the apparatus through the air inlet 12 and the exhaust duct 11 and the filter 14 that is disposed in the exhaust path and collects the fine particles. Furthermore, since the filter 14 passes through the entire width of the apparatus main body 101, the filter 14 can be disposed at a position in the wind speed region of the fan 13 having a high collection efficiency, and the wind speed during exhaust can be reduced, so that a silencing effect can be expected. Further, it is possible to simultaneously prevent the temperature increase of the entire apparatus main body 101 due to heat generated in the vicinity of the fixing device 158 and the prevention of condensation due to water vapor.

DESCRIPTION OF SYMBOLS 1 ... Outer cover 11 ... Exhaust duct 12 ... Intake port 13 ... Fan 14 ... Filter

Claims (8)

Image forming means for forming a toner image on the recording material S using a toner containing a release agent;
Fixing means (158) for thermally fixing the toner image formed on the recording material S by the image forming means;
An exhaust path (11) through which air in the vicinity of the fixing means (158) flows directly above the fixing means (158) and upstream of the discharge roller (161) includes a part of the exhaust path (11). An image forming apparatus formed by the upper exterior cover portion (1). The exhaust path (11) has an intake port (12) in an entire region passing through in a direction perpendicular to the conveying direction of the recording material S immediately above the fixing unit (158). The image forming apparatus described in 1. The image forming apparatus according to claim 1 or 2, wherein a part of the exhaust path (11) passes through the entire width of the apparatus main body (101). The image forming apparatus according to any one of claims 1 to 3, further comprising at least one filter means (14) for collecting fine particles in the middle of the exhaust path (11). The image forming apparatus according to any one of claims 1 to 4, further comprising an exhaust fan (13) in the exhaust path (11). 6. The image forming apparatus according to claim 1, wherein the exhaust fan is disposed at an end of a region in which the exhaust fan passes in a direction perpendicular to the conveyance direction of the recording material. The image forming apparatus according to claim 1, wherein the fixing unit (158) conveys the recording material S vertically upward. 8. The image formation according to claim 1, wherein the guide member from the fixing unit (158) to the discharge roller (161) is not provided with a vent other than the vicinity of the discharge roller (161). apparatus.