The present invention relates to image forming apparatuses.
Image forming apparatuses utilizing electrophotographic processes form an electrostatic latent image on a surface of a photosensitive drum and develop the electrostatic latent image into a toner image for visualization. Such an image forming apparatus includes a static eliminator for eliminating static electricity and an electrostatic latent image that remain redundantly on the surface of the photosensitive drum. The static eliminator performs static elimination by irradiating the surface of the photosensitive drum with light.
In view of environmental friendliness, amorphous silicon, which is excellent in abrasion resistance and durable under long-term use, is used generally in the photosensitive drum. Amorphous silicon has a surface having a molecular structure that is apt to adsorb moisture. As a result, moisture is liable to be adsorbed into the surface of the photosensitive drum. When moisture is adsorbed into the surface of the photosensitive drum, the surface resistance of the photosensitive drum may decrease, thereby reducing the surface potential at an edge of the electrostatic latent image. As a result, image quality may degrade.
In view of the foregoing, it has been proposed to provide in the vicinity of the photosensitive drum, a substrate on which a heating element that heats the surface of the photosensitive drum is mounted (e.g., Patent Literature 1). In an image forming apparatus recited in Patent Literature 1, a light emitting element that eliminates static electricity on the photosensitive drum is mounted on one of main surfaces of the substrate while the heating element that heats the photosensitive drum is mounted on the other main surface of the substrate.
[Patent Literature 1]
Japanese Patent Application Laid-Open Publication No. 2007-264167
However, in the image forming apparatus of Patent Literature 1, in which the light emitting element is mounted on one of the main surfaces of the substrate and the heating element is mounted on the other main surface of the substrate, wiring patterns are formed on the respective opposite surfaces of the substrate, resulting in an increase in man-hour for design. Further, the light emitting element is provided close to the photosensitive drum and the heating element is provided on the opposite side to the light emitting element. Therefore, the surface of the photosensitive drum may be heated insufficiently. This may hinder prevention of degradation of image quality caused due to image deletion in a high moisture environment.
The present invention has been made in view of the aforementioned problems and has its objective of providing an image forming apparatus in which degradation of image quality caused due to image deletion in a high humidity environment can be prevented.
An image forming apparatus according to the present invention is an image forming apparatus that forms an image on a recording medium. The image forming apparatus includes a substrate, a photosensitive drum, a heating element that heats the photosensitive drum, a light emitting element that performs static elimination on the photosensitive drum, and a metal member that transfers heat from the heating element to the photosensitive drum. The light emitting element and the heating element are mounted on one of main surfaces of the substrate. The metal member is in contact with another of the main surfaces of the substrate.
According to the present invention, an image forming apparatus can be provided in which degradation of image quality caused due to image deletion in a high humidity environment can be prevented.
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Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that elements that are the same or equivalent are indicated by the same reference signs in the drawings and description thereof is not repeated.
The metal member 167 transfers heat from the heating elements 163 to the surface of the photosensitive drum 120. Even in a configuration in which the substrate 161 on which the heating elements 163 are mounted is located away from the surface of the photosensitive drum 120, the arrangement of the metal member 167 in the vicinity of the surface of the photosensitive drum 120 can result in efficient heating of the surface of the photosensitive drum 120.
The metal member 167 is disposed such that an end part of the metal member 167 located closest to the photosensitive drum 120 is disposed closer to the photosensitive drum 120 than an end part of the substrate 161 located closest to the photosensitive drum 120. The metal member 167 accordingly reflects light from the light emitting elements 162 and irradiates the surface of the photosensitive drum 120 with the reflected light. Further, through the metal member 167, efficient transfer of heat from the heating elements 163 to the surface of the photosensitive drum 120 can be achieved.
The substrate warping restraining members 165 restrain the substrate 161 from warping caused by heat of the heating elements 163 and can reduce warping of the substrate 161. The substrate warping restraining members 165 extend in the longitudinal direction of the substrate 161. A material of the substrate warping restraining members 165 is not limited specifically as long as it is an insulating material and may preferably be resin among insulating materials.
The cleaner 180 further includes a cleaning blade 171 and a toner collecting screw 172. The cleaning blade 171 scrapes toner remaining on the surface of the photosensitive drum 120. The toner collecting screw 172 conveys the scraped toner to an end part of a toner collecting path.
The substrate warping restraining members 165 are preferably disposed at respective opposite end parts of the substrate 161. In the above configuration, the substrate warping restraining members 165 extend in a direction perpendicular to the longitudinal direction of the substrate 161.
Note that the light emitting elements 162 and the heating elements 163 may be disposed in an alternating manner in a straight line in the longitudinal direction of the photosensitive drum 120, as illustrated in
Referring to
The control board 166 includes a limiting resistor 164. The limiting resistor 164 controls a current value of the light emitting elements 162. Through the limiting resistor 164 controlling the current value of the light emitting elements 162, the amount of light that the light emitting elements 162 emit is adjusted. If the limiting resistor 164 is disposed on the substrate 161, heat of the limiting resistor 164 heats the substrate 161. As a result, the photosensitive drum 120 is heated by the heat of the limiting resistor 164 during static elimination on the photosensitive drum 120 by the light emitting elements 162.
It is noted that the respective circuitries of the static eliminator 160 illustrated in
The image forming section 110 includes a plurality of the photosensitive drums 120, developing devices 130, an exposure device 140, chargers 150, and a fixing device 170. The image forming apparatus 100 may be a printer, for example. The image forming section 110 forms an image on a sheet. The static eliminators 160 each eliminate static electricity remaining on the surface of a corresponding one of the photosensitive drums 120. Note that the static eliminators 160 have been already described with reference to
In image formation, the photosensitive drums 120 rotate counterclockwise and the chargers 150 each electrostatically charge the surface of corresponding one of the photosensitive drums 120 uniformly. The exposure device 140 then irradiates the surfaces of the photosensitive drums 120 with light based on image data input to an image input section from a personal computer or the like, thereby forming electrostatic latent images on the surfaces of the respective photosensitive drums 120. Next, toners in respective colors fly by developing bias voltage to adhere to the respective electrostatic latent images formed on the surfaces of the respective photosensitive drums 120, thereby forming toner images in the respective developing devices 130.
The toner images in the respective colors formed on the surfaces of the respective photosensitive drums 120 are primarily transferred in succession to an intermediate transfer belt by respective primary transfer rollers to be layered in color. In this manner, a full-color toner image is formed on the surface of the intermediate transfer belt.
Paper to which the full-color toner image is transferred is conveyed to the fixing device 170. Heat and pressure by a fixing roller fix the toner image to the surface of the paper. In this manner, a full-color image is formed. The paper on which the full color image is formed is then ejected outside the main body of the image forming apparatus 100 by an ejection roller.
The embodiment of the present invention has been described so far with reference to
The present invention can be utilized in the fields of image forming apparatuses that utilize electrophotographic processes (e.g., printers, copiers, and multifunction peripherals).
Number | Date | Country | Kind |
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2014-057904 | Mar 2014 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2015/054623 | 2/19/2015 | WO | 00 |