JP6734833B2 - Process unit and image forming apparatus - Google Patents

Description

The present invention relates to a process unit included in an electrophotographic image forming apparatus, and more particularly, to a process unit including a charge eliminating section and a cleaning section and an image forming apparatus including the process unit.

In an electrophotographic image forming apparatus, many functional units are arranged around a photosensitive drum, and an image is formed 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, a charge eliminating unit, and the like.

In many image forming apparatuses, in consideration of ease of maintenance and the like, the photosensitive drum and each functional unit are unitized in a single unit or in a plurality of units so that they can be easily inserted into and removed from the apparatus main body. .. In addition, with the demand for miniaturization of the device, 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 light-transmissive member and light emitted from a charge eliminating lamp is applied to a photosensitive drum via the cleaning blade. This eliminates the need for the static elimination lamp to be arranged at a position where the photoconductor drum can be directly irradiated with light, and it becomes easy to secure a space for disposing the static elimination lamp.

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

In the configurations of Patent Documents 1 to 4, the degree of freedom in the arrangement of the static elimination lamps is improved, which facilitates the member arrangement in the limited arrangement space. However, even with the above configuration, the space for disposing the members cannot be reduced, and therefore there is a limit to the effect of downsizing the device.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a process unit and an image forming apparatus that can further reduce the size of 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 bearing member on which an electrostatic latent image is formed and a charge eliminating unit that eliminates residual charges on the surface of the image bearing member are unitized. A light-transmitting cleaning blade, a light emitting portion that emits light for static elimination, and a light guide plate that receives light from the light emitting portion and guides the light to the image carrier to emit 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, and the cleaning blade is provided from the light guide plate to the image. The cleaning light is arranged so as to overlap a part of an optical path emitted toward the carrier, and at least a part of the light emitted from the light guide plate is cleaned from a surface facing the end surface of the cleaning blade on the image carrier side. It is characterized in that the structure is such that it is incident on the blade, passes through the cleaning blade, and is emitted to the image carrier.

According to the above configuration, since the light emitting unit allows light to enter the light guide plate from the side surface (from the direction parallel to the rotation axis direction of the image carrier), the light emitting unit is arranged along the outer peripheral surface of the image carrier. There is no need to do it. As a result, the space for disposing the light emitting unit can be reduced, and the process unit and the image forming apparatus can be downsized.

Further, at least a part of the light emitted from the light guide plate passes through the cleaning blade and is applied to the image carrier. As a result, it is possible to arrange the cleaning blade and the charging unit in close proximity while ensuring the optical path width necessary for removing the charge on the image carrier, and it is possible to downsize the process unit.

Further, 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 connects between the charge removing unit and the charging unit. It can be configured to have a function of a shielding plate for shielding.

According to the above configuration, even if the upstream side cover of the charging unit is omitted, the space between the charging unit and the charge eliminating unit can be shielded by the holder plate. As a result, the side cover disposition area in the charging section can be omitted, and the process unit can be made compact.

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

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

The process unit may have a detachable cover member on the front side of the process unit, and the light emitting unit may be attached to the cover member.

Further, in the above process unit, the light emitting unit attached to the cover member is wire-connected to the image forming apparatus main body, and the process unit is detachable from the image forming apparatus main body when the cover member is attached. It can be configured to have no structure.

According to the above configuration, the process unit cannot be removed with the cover member attached. Accordingly, it is possible to avoid the problem that the process unit is pulled out together with the light emitting unit in the state where the wiring for supplying the electric power to the light emitting unit is connected and the wiring is cut off.

Further, in the above process unit, the image carrier may be a photosensitive drum.

An image forming apparatus of the present invention is characterized by including the process unit described above in order to solve the above problems.

In the process unit and the image forming apparatus of the present invention, it is not necessary to arrange the light emitting portion along the outer peripheral surface of the image carrier, the space for disposing the light emitting portion can be reduced, the process unit can be downsized, and the image forming apparatus can be downsized. There is an effect that it can be realized. Further, it is possible to dispose the cleaning blade and the charging unit in close proximity, and it is possible to reduce the size of the process unit.

FIG. 3 is a diagram schematically showing a configuration around a photosensitive drum in the image forming apparatus. FIG. 3 is a cross-sectional view showing the process unit according to the first embodiment. FIG. 3 is an exploded perspective view of a cleaning unit and a charge eliminating unit in the process unit of FIG. 2. FIG. 3 is a diagram showing a state in which the process unit is mounted on the image forming apparatus. FIG. 6 is a diagram showing a state in which the cover member is removed with the process unit mounted on the image forming apparatus. 11 is a vertical cross-sectional view schematically showing the overall configuration of the digital multi-function peripheral according to Embodiment 3. FIG.

[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 included 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 photoconductor drum 1 is a roller-shaped member that is rotatably driven around the axis in the direction of the arrow, and has a photosensitive film on the surface of which an electrostatic latent image and a toner image are formed. The charger 2 is a main charger provided so as 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 photosensitive drum 1 in the charged state 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 to visualize 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 photoconductor 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 arranged 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 to melt and fix the toner image transferred to the recording paper P.

The cleaning unit 7 uses a cleaning blade to scrape off the 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. The charge removing unit 8 irradiates the outer peripheral surface of the photoconductor drum 1 with light after the cleaning process by the cleaning unit 7, and optically removes the remaining charges.

The process unit according to the first embodiment is a unit in which the photosensitive drum 1, the charger 2, the cleaning unit 7 and the charge eliminating unit 8 shown in FIG. 1 are unitized, and the arrangement configuration is different from that in FIG. A specific configuration of this process unit will be described with reference to FIGS. 2 and 3. 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 eliminating 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 charge eliminating lamp (light emitting portion) 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 arranged along the outer periphery of the photosensitive drum 1.

The cleaning blade 11 is a plate-shaped 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 therein, 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 charge eliminating lamp 15 is, for example, an LED (Light Emitting Diode) light source, and as shown in FIG. 3, makes light enter the light guide plate 12 from the side surface (from the direction parallel to the rotation axis direction of the photosensitive drum 1). It is like this. 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 the incident light from the static elimination lamp is the light reflecting portion 12a. It is reflected to the photosensitive drum side by 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 photoconductor drum 1, it is possible to reduce the space for disposing the static elimination lamp 15, reduce the size of the process unit, and thus the size of the image forming apparatus. Can be changed. In the process unit 10, the light guide plate 12 is arranged 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 downsizing the process unit 10.

A part of the light emitted from the light guide plate 12 is directly applied to the photoconductor drum 1 through the gap between the cleaning blade 11 and the holder plate 13, but the rest of the light passes through the transparent cleaning blade 11 and is exposed to light. 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 applied to the photosensitive drum 1. As a result, the cleaning blade 11 and the main charger 14 can be arranged close to each other, and the process unit 10 can be downsized. Further, the cleaning blade 11 preferably has a diffusive property, which enables uniform light irradiation to the photosensitive drum.

Further, in the process unit 10, the holder plate 13 also functions as a shielding plate that partitions the cleaning unit 7 and the charge removing unit 8 including the cleaning blade 11 and the light guide plate 12 from the main charger 14 that is the charger 2. That is, it is necessary to prevent the light from the discharge lamp 15 from entering the charging area of the charger 2 on the outer peripheral surface of the photosensitive drum 1. Therefore, in a normal image forming apparatus, side covers are provided on both sides of the charger (both sides along the rotation direction of the photoconductor drum) in the charging section, so that the charging area is protected from light from the discharge lamp and other external light. It will not be incident.

On the other hand, in the process unit 10, the side cover on the upstream side of the main charger 14 is omitted, and the space between the main charger 14 and the charge eliminating portion 8 is shielded by the holder plate 13. As a result, the side cover disposition area in the main charger 14 can be omitted, and the process unit 10 can be downsized. The holder plate 13 is preferably formed of a metal plate that is thin, has sufficient strength, and 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 eliminating unit 8 are unitized, but the present invention is not limited to this. In the process unit according to the present invention, at least the cleaning unit and the static elimination unit may be unitized. That is, the photoconductor drum and the charging unit may be unitized separately from the cleaning unit and the charge removing unit, and may be configured as shown in FIG. 2 when mounted in the image forming apparatus.

In the above description, the photosensitive drum is exemplified as the image bearing member 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-shaped member having a photoconductor 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 is configured to be easily inserted into and removed from the image forming apparatus from the front side (the side on which the operation panel is provided). FIG. 4 is a perspective view showing a state in which the process unit is attached to the image forming apparatus.

The process unit 10 includes a front side plate 16 and a rear side plate in order to hold the photoconductor 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 (positional relationship shown in FIG. 2). A plate (not shown) holds these members. 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 the screw 18.

Further, in the process unit 10, a cover member 17 is attached to the front side plate 16 further to the front side. The static elimination lamp 15 is attached to the cover member 17. That is, when the cover member 17 is attached 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, in the process unit 10, it becomes easy to replace only the static elimination lamp 15 without removing the entire unit, and maintainability is improved. 4 shows a state in which the cover member 17 is attached, and FIG. 5 shows a state in which the cover member 17 is removed.

The cover member 17 is attached so as to cover at least one of the screws (here, the screw 18a shown in FIG. 5) that fixes the process unit 10. Therefore, with the cover member 17 attached, the process unit 10 cannot be removed. As a result, it is possible to avoid the problem that the process unit 10 is pulled out together with the static elimination lamp 15 in a state in which the wiring for supplying electric power to the static elimination lamp 15 is connected and the wiring is cut off.

[Embodiment 3]
The third embodiment will describe a configuration example of an image forming apparatus to which the process unit described in the first and second embodiments is applied. In the third embodiment, as the 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 illustrated.

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

The scanner 20 is provided with a document set tray, an automatic document feeder (RADF, Reversing Automatic Document Feeder), and the like. Further, the scanner 20 includes a document reading device, and the document reading device has 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 accommodate recording paper P of different size. The recording paper P on which an image has been formed is discharged and stacked on the discharge tray 22.

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

1 Photoconductor drum (image carrier)
2 charger 3 exposure unit 4 developing unit 5 transfer unit 6 fixing unit 7 cleaning unit 8 static eliminator 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 Ejection Tray 100 Digital Multifunction Machine (Image Forming Device)

Claims (6)

A process unit in which a cleaning unit that removes residual toner on an image bearing member on which an electrostatic latent image is formed and a charge eliminating unit that eliminates residual charges on the surface of the image bearing member are unitized,
A cleaning blade made of a translucent plate member,
A light emitting unit that emits light for static elimination,
Light is incident from the light emitting unit, and a light guide plate that guides and emits the light to the image carrier,
The light emitting unit is arranged 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.
The cleaning blade is arranged so as to overlap a part of an optical path emitted from the light guide plate toward the image carrier, and the plate thickness direction is a direction orthogonal to the optical path, and the image carrier. Has a flat plate portion whose side in contact with is parallel to the rotation axis of the image carrier ,
The flat plate portion has a first surface that is an end surface on the image carrier side, and a second surface that faces the first surface along an in-plane direction orthogonal to the plate thickness direction of the flat plate portion. Has
At least a part of the light emitted from the light guide plate is incident on the cleaning blade from the second surface of the cleaning blade, passes through the cleaning blade, and is transmitted from the first surface to the image carrier. A process unit having a structure for emitting light. The process unit according to claim 1, wherein
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 includes a protrusion that protrudes from the light guide plate toward the image carrier, and has a function of a shield plate that shields between the charge removing unit and the charging unit. A process unit according to claim 1 or 2, wherein
When the side on which the operation panel of the image forming apparatus is provided when the process unit is mounted on the image forming apparatus is the front side,
The process unit, wherein the light emitting unit is disposed on a side surface of the light guide plate on the front side. The process unit according to any one of claims 1 to 3,
When the side on which the operation panel of the image forming apparatus is provided when the process unit is mounted on the image forming apparatus is the front side,
The front side of the process unit has a removable cover member,
The process unit is characterized in that the light emitting unit is supplied with electric power from the image forming apparatus main body by wiring connection and is attached to the cover member. The 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.