JP2015087697A - Process unit and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process unit and an image forming apparatus that enable a reduction in size of the image forming apparatus.SOLUTION: A process unit 10 includes a cleaning blade 11 having translucency, a static elimination lamp 15, and a light guide plate 12 that guides the light from the static elimination lamp 15 to a photoreceptor drum 1 and emits the light. The static elimination lamp 15 is arranged on a side face of the light guide plate 12, and at least a part of the light emitted from the light guide plate 12 transmits through the cleaning blade 11 to be emitted to the photoreceptor drum 1.

Description

  The present invention relates to a process unit provided in an electrophotographic image forming apparatus, and more particularly to a process unit having a charge removal unit and a cleaning unit and an image forming apparatus including the process unit.

  In an electrophotographic image forming apparatus, a large number of functional units are arranged around a photosensitive drum, and image formation is performed by the cooperation of these functional units. Examples of the functional unit used include a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit.

  In many image forming apparatuses, in consideration of ease of maintenance, the photosensitive drum and each functional unit are united as a single unit or a plurality of units, and can be easily inserted into and removed from the apparatus main body. . In addition, with the demand for downsizing of the apparatus, it is required to arrange components in a limited arrangement space in each unit.

  Patent Documents 1 to 4 disclose a technique in which a cleaning blade is used as a translucent member and light emitted from a static elimination lamp is irradiated onto a photosensitive drum via the cleaning blade. As a result, it is not necessary to dispose the static elimination lamp at a position where it is possible to directly irradiate the photosensitive drum, and it is easy to secure an arrangement space for the static elimination lamp.

JP 2008-225319 A JP 2002-244519 A JP-A-7-261616 Japanese Patent Laid-Open No. 61-169876

  In the configurations of Patent Documents 1 to 4, the arrangement of members in a limited arrangement space is facilitated by improving the degree of freedom of arrangement of the static elimination lamp. However, even with the above configuration, the arrangement space of the members cannot be reduced, and thus there is a limit to the effect of downsizing the apparatus.

  SUMMARY An advantage of some aspects of the invention is that it provides a process unit and an image forming apparatus capable of further downsizing the image forming apparatus.

  The process unit of the present invention is a process unit in which a cleaning unit that removes residual toner on an image carrier on which an electrostatic latent image is formed and a static elimination unit that removes residual charges on the surface of the image carrier are unitized. A light-transmitting cleaning blade, a light emitting unit that emits light for discharging, and a light guide plate that receives light from the light emitting unit and guides the light to the image carrier and emits the light. And the light emitting unit is disposed on a side surface of the light guide plate so that light is incident on the light guide plate from a direction parallel to a rotation axis direction of the image carrier, and at least one of light emitted from the light guide plate. The portion is characterized in that it has a structure that passes through the cleaning blade and is emitted to the image carrier.

  According to the above configuration, since the light emitting part is incident on the light guide plate from the side surface (from a direction parallel to the rotation axis direction of the image carrier), the light emitter is arranged along the outer peripheral surface of the image carrier. There is no need to do. As a result, the arrangement space of the light emitting section can be reduced, and the process unit can be downsized, and thus the image forming apparatus can be downsized.

  Further, at least part of the light emitted from the light guide plate passes through the cleaning blade and is irradiated onto the image carrier. As a result, the cleaning blade and the charging unit can be disposed close to each other, and the process unit can be reduced in size.

  The process unit includes a holder plate that holds the light guide plate, and a charging unit that charges the surface of the image carrier, and the holder plate is disposed between the charge removal unit and the charging unit. It can be set as the structure which has the function of the shielding board which shields.

  According to said structure, even if the upstream side cover in a charging part is abbreviate | omitted, between a charging part and a static elimination part can be shielded with a holder board. Thereby, the arrangement | positioning area | region of the side cover in a charging part can be omitted, and a process unit can be reduced in size.

  The process unit may be configured such that the light emitting unit is disposed on a front side surface of the light guide plate.

  According to the above configuration, it becomes easy to replace only the light emitting unit without removing the entire unit, and the maintainability of the image forming apparatus is improved.

  In addition, the process unit includes a cover member that is detachable on the front side of the process unit, and the light emitting unit is attached to the cover member, and the side surface of the light guide plate when the cover member is attached The process unit can be structured such that it cannot be removed from the image forming apparatus main body when the cover member is mounted.

  According to said structure, in the state in which the cover member was attached, extraction of a process unit cannot be performed. Accordingly, it is possible to avoid the problem that the process unit is pulled out together with the light emitting unit in a state where the wiring for supplying power to the light emitting unit is connected, and the wiring is cut off.

  In the process unit, the image carrier may be a photosensitive drum.

  In order to solve the above-described problems, an image forming apparatus according to the present invention includes the process unit described above.

  The process unit and the image forming apparatus of the present invention do not require the light emitting unit to be arranged along the outer peripheral surface of the image carrier, can reduce the arrangement space of the light emitting unit, reduce the size of the process unit, and hence the size of the image forming apparatus. There is an effect that can be achieved. In addition, the cleaning blade and the charging unit can be disposed close to each other, and the process unit can be reduced in size.

FIG. 2 is a diagram schematically illustrating a configuration around a photosensitive drum in an image forming apparatus. 2 is a cross-sectional view showing a process unit according to Embodiment 1. FIG. FIG. 3 is an exploded perspective view of a cleaning unit and a charge removal unit in the process unit of FIG. FIG. 3 is a diagram illustrating a state in which a process unit is attached to the image forming apparatus. FIG. 4 is a diagram illustrating a state where a cover member is removed in a state where the process unit is mounted on the image forming apparatus. FIG. 6 is a longitudinal sectional view schematically showing an overall configuration of a digital multifunction peripheral according to a third embodiment.

[Embodiment 1]
In the first embodiment, a process unit to which the present invention is applied will be described with reference to the drawings. The process unit according to the first embodiment is provided in an electrophotographic image forming apparatus. First, a general basic arrangement around the photosensitive drum (image carrier) in the image forming apparatus will be described with reference to FIG.

  The photosensitive drum 1 is a roller-like member provided so as to be rotatable around an axis in an arrow direction, and has a photosensitive film on which an electrostatic latent image and a toner image are formed. The charger 2 is a main charger provided to face the outer peripheral surface of the photosensitive drum 1, and charges the outer peripheral surface of the photosensitive drum 1 to a predetermined polarity and potential.

  The exposure device 3 (see FIG. 6) irradiates the charged photosensitive drum 1 with the signal light L corresponding to the image data. As a result, an electrostatic latent image corresponding to the image data is formed on the outer peripheral surface of the photosensitive drum 1.

  The developing device 4 supplies the toner T to the outer peripheral surface of the photosensitive drum 1 and visualizes the electrostatic latent image as a toner image. The transfer device 5 applies a transfer bias from the back surface of the recording paper P passing between the photosensitive drum 1 and the transfer device 5, and transfers the toner image onto the recording paper P.

  The fixing device 6 includes a fixing roller 61 and a pressure roller 62, and is disposed downstream of the transfer device 5 along the conveyance path of the recording paper P. The fixing device 6 heats and pressurizes the recording paper P passing through the fixing nip portion, thereby melting and fixing the toner image transferred to the recording paper P.

  The cleaning unit 7 scrapes and removes toner T, paper dust, and the like remaining on the outer peripheral surface of the photosensitive drum 1 from the outer peripheral surface of the photosensitive drum 1 with a cleaning blade. The neutralization unit 8 irradiates light on the outer peripheral surface of the photosensitive drum 1 after the cleaning process by the cleaning unit 7 to optically neutralize the remaining charges.

  The process unit according to the first embodiment is obtained by unitizing the photosensitive drum 1, the charger 2, the cleaning unit 7, and the charge removal unit 8 shown in FIG. A specific configuration of this process unit will be described with reference to FIGS. 2 is a sectional view showing the process unit 10 according to the first embodiment, and FIG. 3 is an exploded perspective view of the cleaning unit 7 and the charge removal unit 8 in the process unit 10.

  The process unit 10 includes a photosensitive drum 1, a cleaning blade 11, a light guide plate 12, a holder plate 13, a main charger 14, and a static elimination lamp (light emitting unit) 15 (see FIG. 3).

  The cleaning blade 11, the light guide plate 12, the holder plate 13, and the main charger 14 are members whose longitudinal direction is the rotation axis direction of the photosensitive drum 1, and are disposed along the outer periphery of the photosensitive drum 1.

  The cleaning blade 11 is a plate-like member provided so that the edge on one side contacts the outer peripheral surface of the photosensitive drum 1. The light guide plate 12 guides the light emitted from the static elimination lamp 15 inside and emits the light toward the photosensitive drum 1. The holder plate 13 is a member that fixes and supports the light guide plate 12. The main charger 14 charges the outer peripheral surface of the photosensitive drum 1 as a charger.

  The static elimination lamp 15 is an LED (Light Emitting Diode) light source, for example, and makes light incident on the light guide plate 12 from the side surface (from a direction parallel to the rotation axis direction of the photosensitive drum 1) as shown in FIG. It is like that. Further, the back surface of the light guide plate 12 (the surface opposite to the surface facing the photosensitive drum 1) is a light reflecting portion 12a on which a large number of irregularities are formed, and incident light from the static elimination lamp is reflected by this light reflecting portion. Reflected by the photosensitive drum 12a. That is, in the process unit 10, since it is not necessary to dispose the static elimination lamp 15 along the outer peripheral surface of the photosensitive drum 1, the arrangement space of the static elimination lamp 15 can be reduced, the process unit can be downsized, and the image forming apparatus can be downsized. Can be realized. In the process unit 10, a light guide plate 12 is disposed around the photosensitive drum 1 instead of the static elimination lamp, but the light guide plate 12 is sufficiently smaller than the static elimination lamp (when used as a line light source). Since it is a member, the configuration of the present invention is sufficiently useful for reducing the size of the process unit 10.

  A part of the light emitted from the light guide plate 12 is directly irradiated to the photosensitive drum 1 through a gap between the cleaning blade 11 and the holder plate 13, and the rest is transmitted through the light-transmitting cleaning blade 11 to be photosensitive. The body drum 1 is irradiated. In the present invention, at least a part of the light emitted from the light guide plate 12 passes through the cleaning blade 11 and is irradiated onto the photosensitive drum 1. As a result, the cleaning blade 11 and the main charger 14 can be disposed close to each other, and the process unit 10 can be reduced in size. Further, the cleaning blade 11 preferably has diffusibility, and this enables uniform light irradiation to the photosensitive drum.

  In the process unit 10, the holder plate 13 also functions as a shielding plate that partitions the cleaning unit 7 and the charge removal unit 8 including the cleaning blade 11 and the light guide plate 12 and the main charger 14 that is the charger 2. That is, it is necessary to avoid the light from the static elimination lamp 15 entering the charging area by the charger 2 on the outer peripheral surface of the photosensitive drum 1. For this reason, in a normal image forming apparatus, side covers are provided on both sides of the charger in the charging unit (both sides along the rotation direction of the photosensitive drum), and light from the static elimination lamp and other external light are supplied to the charging area. It is not incident.

  On the other hand, in the process unit 10, the upstream side cover of the main charger 14 is omitted, and the space between the main charger 14 and the charge removal unit 8 is shielded by the holder plate 13. Thereby, the arrangement | positioning area | region of the side cover in the main charger 14 can be abbreviate | omitted, and the process unit 10 can be reduced in size. The holder plate 13 is preferably made of a metal plate that is thin and has sufficient strength and also has a light shielding effect.

  The process unit 10 described above is a unit in which the photosensitive drum 1, the charger 2, the cleaning unit 7, and the charge removal unit 8 are unitized, but the present invention is not limited to this. In the process unit according to the present invention, it is sufficient that at least the cleaning unit and the charge removal unit are unitized. That is, the photosensitive drum and the charging unit may be unitized separately from the cleaning unit and the charge eliminating unit, and may be configured as shown in FIG. 2 when mounted on the image forming apparatus.

  In the above description, the photosensitive drum is exemplified as the image carrier on which the electrostatic latent image is formed, but the present invention is not limited to this. As the image carrier, for example, a belt-like member having a photosensitive layer formed on the surface and spanned between a plurality of rollers may be used.

[Embodiment 2]
In the second embodiment, an example of a more detailed structure of the process unit 10 will be described.

  The process unit 10 can be easily inserted into and removed from the image forming apparatus from the front side (side on which the operation panel is provided). FIG. 4 is a perspective view showing a state in which the process unit is mounted on the image forming apparatus.

  The process unit 10 includes a front side plate 16 and a rear side in order to hold the photosensitive drum 1, the cleaning blade 11, the light guide plate 12, the holder plate 13, and the main charger 14 in a predetermined positional relationship (the positional relationship shown in FIG. 2). These members are held between plates (not shown). After the process unit 10 is inserted into the image forming apparatus, the front side plate 16 is fixed to the housing of the image forming apparatus with screws 18.

  In the process unit 10, a cover member 17 is attached to the front side of the front side plate 16. A static elimination lamp 15 is attached to the cover member 17. That is, by attaching the cover member 17 to the front side plate 16, the static elimination lamp 15 faces the front side surface of the light guide plate 12, and light can enter the light guide plate 12. As a result, the process unit 10 can easily replace only the static elimination lamp 15 without removing the entire unit, and the maintainability is improved. 4 shows a state where the cover member 17 is attached, and FIG. 5 shows a state where the cover member 17 is removed.

  The cover member 17 is attached so as to cover at least one of the screws for fixing the process unit 10 (here, the screw 18a shown in FIG. 5). For this reason, in a state where the cover member 17 is attached, the process unit 10 cannot be extracted. As a result, it is possible to avoid such a problem that the process unit 10 is pulled out together with the charge removal lamp 15 in a state in which the wiring for supplying power to the charge removal lamp 15 is connected, and the wiring is cut off.

[Embodiment 3]
In the third embodiment, a configuration example of an image forming apparatus to which the process unit described in the first and second embodiments is applied will be described. In the third embodiment, as an image forming apparatus, a digital multi-function peripheral 100 capable of printing a document read by the scanner 20 or printing image data input from an external device via a network is exemplified.

  FIG. 6 is a longitudinal sectional view schematically showing the overall configuration of the digital multifunction peripheral 100. The digital multifunction peripheral 100 includes a photosensitive drum 1, a charger 2, an exposure unit 3, a developing unit 4, a transfer unit 5, a fixing unit 6, a cleaning unit 7, a charge eliminating unit 8, a scanner 20, a paper feed tray 21, and a paper discharge tray. 22 is included. In the digital multifunction peripheral 100, the process unit 10 described in the first and second embodiments is used as the photosensitive drum 1, the charger 2, the cleaning unit 7, and the charge removal unit 8.

  The scanner 20 is provided with a document setting tray, an automatic document feeder (RADF, Reversing Automatic Document Feeder), and the like. The scanner 20 includes a document reading device, and the document reading device includes a document placing table and a document scanning device.

  The paper feed tray 21 is a tray that stores recording paper P such as plain paper, coated paper, color copy paper, and OHP film. A plurality of paper feed trays 21 may be provided, and each paper feed tray 21 may store recording paper P having different sizes. The recording paper P on which an image is formed is discharged and stacked on the paper discharge tray 22.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

1 Photosensitive drum (image carrier)
DESCRIPTION OF SYMBOLS 2 Charging device 3 Exposure device 4 Developing device 5 Transfer device 6 Fixing device 7 Cleaning unit 8 Static elimination unit 10 Process unit 11 Cleaning blade 12 Light guide plate 13 Holder plate 14 Main charger (charging unit)
15 Static elimination lamp (light emitting part)
16 Front side plate 17 Cover member 18 Screw 20 Scanner 21 Paper feed tray 22 Paper discharge tray 100 Digital multifunction peripheral (image forming apparatus)

Claims (6)

A process unit in which a cleaning unit that removes residual toner on an image carrier on which an electrostatic latent image is formed and a static elimination unit that neutralizes residual charges on the surface of the image carrier are unitized,
A translucent cleaning blade;
A light emitting unit for emitting static elimination light;
A light guide plate that receives light from the light emitting unit, guides the light to the image carrier, and emits the light.
The light emitting unit is disposed on a side surface of the light guide plate so that light is incident on the light guide plate from a direction parallel to a rotation axis direction of the image carrier.
A process unit having a structure in which at least a part of light emitted from the light guide plate passes through the cleaning blade and is emitted to the image carrier. The process unit according to claim 1,
A holder plate for holding the light guide plate;
A charging unit for charging the surface of the image carrier,
The process unit, wherein the holder plate has a function of a shielding plate that shields between the charge removal unit and the charging unit. The process unit according to claim 1 or 2,
The process unit, wherein the light emitting unit is arranged on a front side surface of the light guide plate. A process unit according to any one of claims 1 to 3,
It has a detachable cover member on the front side of the process unit,
The light emitting unit is attached to the cover member and disposed on a side surface of the light guide plate when the cover member is attached.
The process unit has a structure that cannot be removed from the main body of the image forming apparatus when the cover member is mounted. A process unit according to any one of claims 1 to 4,
The process unit, wherein the image carrier is a photosensitive drum.   An image forming apparatus comprising the process unit according to claim 1.