JP4179463B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, a printer, or a multifunction machine having both functions. More specifically, the present invention relates to a photoconductor unit having a charger for performing corona discharge, and development for supplying toner. The present invention relates to an image forming apparatus in which a container unit is detachably provided in an image forming apparatus main body.
[0002]
[Prior art]
Conventionally, there is an image forming apparatus as shown in FIG. FIG. 4 is a cross-sectional view showing a state in which the developing unit 101 and the photosensitive unit 102 in the image forming apparatus are mounted in the image forming apparatus main body. The developing unit 101 includes a developing sleeve 104 that contacts the photosensitive drum 103 in the photosensitive unit 102 and a toner supply unit 105 that supplies toner to the developing sleeve 104. In addition to the photosensitive drum 103 and the charger 106 that generates corona discharge disposed around (above) the photosensitive drum unit 102, the photosensitive unit 102 is a static eliminator and a paper separating unit that separates the paper from the photosensitive drum 103. And a cleaning device or the like.
[0003]
The photosensitive drum 103 described above is rotationally driven in a clockwise direction in FIG. 4 at a predetermined process speed (circumferential speed) by a driving unit (not shown). The surface of the photosensitive drum 103 is uniformly charged by the charger 106 with a predetermined polarity and potential.
[0004]
On the photosensitive drum 103 after charging, an electrostatic latent image is formed by an exposure device (not shown), and ON / OFF control is performed based on image information input from an image processing unit (not shown). The surface of the body drum 103 is irradiated, the electric charge of the laser light irradiation portion is removed, and an electrostatic latent image corresponding to image information is formed. The electrostatic latent image formed on the surface of the photosensitive drum 103 is developed as a toner image by electrostatically attaching a charged toner by the developing sleeve 104. As this toner, powder made of synthetic resin is generally used.
[0005]
As shown in FIG. 4, the charger 106 includes a corona wire and a grid in a charger case 107 having a substantially U-shaped conductive cross section having an opening 107 </ b> A for taking in outside air at the top. Yes. In such a charger 106, when a charging voltage is applied to the photosensitive drum 103, an ion flow generated by discharge flows from the corona wire toward the photosensitive drum 103, flows around the developing unit unit 101, and is charged again. It entered the charger 106 through the opening 107A in the upper part of the charger case 107 (the thick arrow shown in FIG. 4 indicates the ion flow). As a result, the ion flow becomes a circulation flow between the charger 106 and the developing unit 101, and the ozone concentration is increased. Further, since the ion flow also entrains the toner scattered from the developing unit 101, the contamination of the charger 106 is further promoted. Such contamination of the charger 106 destabilizes the charged state, leading to defective formed images.
[0006]
Therefore, as a countermeasure, as shown in FIG. 4, the side wall of the charger 106 is provided with a shielding sheet 108 for isolating the charger 106 from the developing unit 101, or as shown in FIG. In some cases, the height of the ion flow is increased so that the ion flow does not re-enter the upper portion of the charger 106, that is, the charger case 107 is enlarged to shield the ion flow.
[0007]
By the way, in the image forming apparatus, for example, when a paper feeding failure (JAM) or the like occurs, it is necessary to take out the developing unit and the photosensitive unit including the photosensitive member from the image forming apparatus main body and perform processing. At this time, there is a possibility that the photosensitive member is exposed to light or an object accidentally touches the photosensitive member to damage the photosensitive member.
[0008]
For this reason, at least a photoconductor unit including the photoconductor is provided with a protective cover for covering the exposed portion of the photoconductor. As an image forming apparatus provided with a protective cover for a photoconductor, there is an image forming apparatus in which the protective cover serves both as a protective function for the photoconductor and a guide function for a sheet conveyance path (see, for example, Patent Document 1 and Patent Document 2). In addition to this, there is known one in which a protective cover is positioned between the fixing device and the toner box (for example, see Patent Document 3).
[0009]
[Patent Document 1]
Japanese Patent Laid-Open No. 1-179952 (page 5, FIG. 1)
[Patent Document 2]
JP-A-4-156470 (5th page, Fig. 1)
[Patent Document 3]
Japanese Patent Laid-Open No. 3-157672 (page 4, FIG. 1).
[0010]
[Problems to be solved by the invention]
In the above-described image forming apparatus provided with the shielding sheet 108 that shields the ion flow, the width dimension of the shielding sheet 108 needs to be equal to or larger than the width dimension of the charger 106. There was a problem of poor mounting. Further, as described above, in the image forming apparatus in which the charger case 107 is large (high), the charger case 107 itself has a problem of high cost.
[0011]
In addition, the techniques disclosed in Patent Documents 1 to 3 do not solve the problem of ion flow.
[0012]
Accordingly, an object of the present invention is to form an image that can block the circulation of the ion flow generated in the charger without increasing the number of parts such as a shielding sheet and increasing the cost, and without increasing the size of the charger itself. To provide an apparatus.
[0013]
[Means for solving the problems]
According to the first aspect of the present invention, a charger for applying a charging voltage to the photosensitive member by corona discharge is disposed around the photosensitive member, and the exposed portion of the photosensitive member when taken out from the image forming apparatus main body. a photosensitive member unit cover and a protective cover that moves to the retracted position when mounted on the image forming apparatus main body, the developing unit of an electrostatic latent image formed on the photosensitive member for supplying toner to visualize Are related to an image forming apparatus detachably provided in the image forming apparatus main body. In the present invention , after the photosensitive unit is mounted on the image forming apparatus main body, the developing unit is mounted on the image forming apparatus main body. The exposed portion of the photoconductor is a region extending from the surface of the photoconductor unit facing the developing unit to the lower surface of the photoconductor unit. The retracted position of the protective cover is a space between the charger and the developing unit. In addition, the protective cover is integrally provided with an operation lever and is rotatably supported by the photoconductor unit. An engagement member that engages with the operation lever is provided on the image forming apparatus main body side. When the photoconductor unit is mounted on the image forming apparatus main body, the operation lever is engaged with the engagement member, and the protective cover is moved from the position covering the exposed portion of the photoconductor to the retracted position. It is designed to move up and down. Further, when the photoconductor unit is removed from the image forming apparatus main body, the operation lever is detached from the engaging member, and the protective cover is self-weighted at a position covering the exposed portion of the photoconductor from the retracted position. It is designed to move downward.
[0014]
The invention according to claim 2 relates to the image forming apparatus according to claim 1. The image forming apparatus according to the present invention is characterized in that the protective cover blocks an ion flow and an air flow containing toner flowing between the charger and the developing unit.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, details of an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. However, it should be noted that the drawings are schematic and dimensional ratios between the members are different from actual ones. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings is contained.
[0019]
In the present invention, a charger for applying a charging voltage by corona discharge is disposed around the photoconductor, and covers the exposed portion of the photoconductor when taken out from the image forming apparatus main body, and is attached to the image forming apparatus main body. a photoreceptor unit comprising a protective cover that moves to the retracted position when, provided detachably electrostatic latent image formed on the photosensitive member and the developing unit for supplying toner to visualize, but the image forming apparatus main body The gist of the image forming apparatus is that the retracted position of the protective cover is located between the charger and the developer unit to shield the ion flow.
[0020]
[Schematic configuration of image forming apparatus]
As shown in FIG. 1, an image forming apparatus 10 according to the present embodiment includes a sheet feeding unit 14 that feeds a sheet-like recording material 12 from a sheet feeding tray 13 in an image forming apparatus main body 11, and this sheet feeding. A sheet conveying section 15 that conveys the recording material 12 fed from the section 14 along the sheet conveying path R, an image forming section 16 that transfers a toner image to the recording material 12 conveyed by the sheet conveying section 15, and A fixing device 17 that fixes the toner image to the recording material 12 onto which the toner image has been transferred by the image forming unit 16, and a discharge unit that discharges the recording material 12 on which the toner image has been fixed by the fixing device 17 onto the paper discharge tray 18. 19 and is schematically configured. Here, as the recording material 12, for example, paper, plastic film, cloth, OHP sheet, or the like can be applied.
[0021]
The image forming unit 16 includes a photoreceptor unit 30, a developing unit 40, a transfer roller 21, and the like. Further, the photosensitive unit 30 and the developing unit 40 are guided by a pair of guide rails (not shown) formed in the image forming apparatus main body 11 so as to face each other and are supported at predetermined positions.
[0022]
(Configuration of photoconductor unit)
As shown in FIG. 2, the photoconductor unit 30 includes a photoconductor drum 31 at a lower portion on the facing surface 30 </ b> A side that faces the developing device unit 40. A charger 32 is disposed above the photosensitive drum 31 in the photosensitive unit 30. An opening 32 </ b> A is formed in the upper portion of the charger 32. In addition to the charger 32, a cleaner, a static eliminator, etc. (not shown) are arranged from the charger 32 toward the upstream side of rotation in addition to the charger 32. Further, for example, laser light can enter the photosensitive drum 31 from an exposure device (not shown) at a position downstream in the rotation direction from the charger 32.
[0023]
In the photoreceptor unit 30 of the present embodiment, as shown in FIG. 2, a protective cover 50 is provided to cover the photoreceptor drum 31 exposed in a region extending from the facing surface 30 </ b> A of the photoreceptor unit 30 to the bottom surface. The protective cover 50 is formed by bending a substantially rectangular plate having a width dimension substantially the same as the width dimension of the photosensitive drum 31 in the rotation axis direction so as to follow the outer peripheral surface of the photosensitive drum 31. It is made of a material that can block the circulation of the ion flow, for example, a synthetic resin.
[0024]
The protective cover 50 is rotatably supported with respect to the photoreceptor unit 30 at the upper part on both sides in the width direction. On both sides of the rotation support shaft 51 of the protective cover 50, operation levers 52 formed integrally with the rotation support shaft 51 are provided. As shown in FIG. 2, the operation lever 52 is rotated in the direction indicated by the thick arrow A so that the protective cover 50 is flipped up to expose the photosensitive drum 31. The operation lever 52 is engaged with an engagement member 60 provided on the image forming apparatus main body 11 side in the direction of arrow A when the photosensitive unit 30 is inserted into the image forming apparatus main body 11. It is designed to rotate. The photosensitive unit 30 is inserted into the image forming apparatus main body 11 prior to the developing unit 40.
[0025]
(Developer unit configuration)
As shown in FIG. 1, the developing device unit 40 is provided with a developing sleeve 41 in contact with the photosensitive drum 31 when mounted on the lower part of the surface facing the photosensitive unit 30. A toner hopper 42 for supplying toner is formed on the surface of the developing unit 40 opposite to the surface facing the photoconductor unit 30. Further, a toner replenishing unit 43 is provided between the toner hopper 42 and the developing sleeve 41. Similar to the photosensitive unit 30, the developing unit 40 is guided and supported along a pair of rails formed in the image forming apparatus main body 11.
[0026]
[Operation and operation of image forming apparatus]
Next, operations and operations of the image forming apparatus 10 having the above-described configuration will be described.
[0027]
First, as shown in FIG. 1, in a state where the photoconductor unit 30 and the developing device unit 40 are inserted and mounted in the image forming apparatus main body 11, as shown by a thick arrow in FIG. When a predetermined charging voltage is applied to the photosensitive drum 31 by the corona discharge generated in step 1, an ion flow is generated and the ion flow flows to the developing sleeve 41 side. However, since the protective cover 50 on the photoconductor unit 30 side is in a state of being flipped up (a state in the retracted position), even if toner powder scattered from the developer unit 40 side is included in the ion flow, the protective cover 50 By blocking the ion flow, it is possible to prevent the ion flow including the toner powder from flowing into the charger 32 side.
[0028]
For example, in the state shown in FIG. 1, for example, when a paper feeding failure (JAM) or the like occurs and the developing unit 40 or the photosensitive unit 30 is taken out from the image forming apparatus main body 11 and JAM processing is performed, first, If the developing unit 40 is taken out of the image forming apparatus main body 11 along a rail provided in the image forming apparatus main body 11, then the photosensitive unit 30 is taken out of the image forming apparatus main body 11 along the rail. Good. At this time, when the photosensitive unit 30 is taken out along the rail, the engaging member 60 on the image forming apparatus main body 11 side is separated from the operation lever 52, so that the protective cover 50 is lowered by its own weight and the photosensitive drum 31 is exposed. Displace to a position that covers the part. For this reason, even if the photosensitive unit 30 is taken out of the image forming apparatus main body 11, the photosensitive drum 31 is protected by the protective cover 50 and can be prevented from being damaged.
[0029]
Further, when the developing unit 40 and the photosensitive unit 30 are taken out from the image forming apparatus main body 11 and the JAM processing is completed and the photosensitive unit 30 is inserted into the image forming apparatus main body 11, as shown in FIG. The operating lever 52 is automatically engaged with the engaging member 60 and rotated in the direction indicated by the arrow A. With this rotation, the protective cover 50 is flipped up and the photosensitive drum 31 is exposed. If the developing unit 40 is inserted into the image forming apparatus main body 11 in this state, the developing sleeve 41 can be brought into contact with the photosensitive drum 31. Further, the protective cover 50 that is flipped up at this time is housed in the developing device unit 40 and positioned between the charger 32 and the developing sleeve 41 as shown in FIG.
[0030]
In the image forming apparatus 10 according to the present embodiment described above, the retracting position of the protective cover 50 of the photosensitive drum 31 is set between the charger 32 and the developing unit 40, whereby the photosensitive unit 30 is formed with an image. It is possible to prevent the photosensitive drum 31 from being damaged in the state of being taken out from the apparatus main body 11 and to block the ion flow generated by the corona discharge in the charger 32. Therefore, the charging voltage can be satisfactorily applied by the charger 32 without using a conventional shielding sheet or the like. In addition, since the charger 32 and the developing unit 40 are shielded in a state where the protective cover 50 is flipped up, it is not necessary to increase the size of the charger itself.
[0031]
[Other embodiments]
It should not be understood that the above description and drawings, which form part of the disclosure of the embodiments of the present invention, limit the present invention. From this disclosure, various alternative embodiments and operational techniques will be apparent to those skilled in the art.
[0032]
For example, in the above-described embodiment, the movement of the protective cover 50 is determined by the positional relationship between the operation lever 52 and the engaging member 60. However, the protective cover 50 is removed when the developing unit 40 is removed from the image forming apparatus main body 11. Of course, it may be set so that 50 can move to a position covering the photosensitive drum 31.
[0033]
In the above embodiment, the protective cover 50 is rotated by the operation lever 52 formed integrally with the rotation support shaft 51. However, the protective cover 50 is located between the exposed portion of the photosensitive drum 31 and the retracted position. The movement of the protective cover 50 is not limited to the rotation mechanism as long as it can move between them, and for example, a slide mechanism or the like may be used.
[0034]
【The invention's effect】
As is apparent from the above description, according to the present invention, low-cost image formation that can reliably block the circulation of the ion flow generated in the charger without causing an increase in the number of parts or an increase in the size of the charger. An apparatus can be realized.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view of a photoconductor unit according to an embodiment of the present invention.
FIG. 3 is a cross-sectional view of a main part showing a photosensitive unit and a developing unit according to the embodiment of the present invention.
FIG. 4 is a cross-sectional view of a main part of a conventional image forming apparatus.
FIG. 5 is a cross-sectional view of a main part of another conventional image forming apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus, 30 ... Photoconductor unit, 31 ... Photoconductor drum, 32 ... Charger, 40 ... Developer unit, 41 ... Developing sleeve, 50 ... Protective cover, 51 ... Rotation Support shaft, 52 …… Operating lever, 60 …… Locking member

Claims (2)

A charger for applying a charging voltage to the photosensitive member by corona discharge is disposed around the photosensitive member, covers an exposed portion of the photosensitive member when taken out from the main body of the image forming device, and the main body of the image forming device. a photoreceptor unit comprising a protective cover that moves to the retracted position when mounted on the electrostatic latent image formed on the photosensitive member and the developing unit for supplying toner to visualize said image forming apparatus main body An image forming apparatus detachably provided on the image forming apparatus,
After the photosensitive unit is mounted on the image forming apparatus main body, the developing unit is mounted on the image forming apparatus main body.
The exposed portion of the photoconductor is a region extending from the surface of the photoconductor unit facing the developing unit to the lower surface of the photoconductor unit,
The retracted position of the protective cover is a space between the charger and the developer unit,
The protective cover is integrally provided with an operation lever and is rotatably supported by the photosensitive unit.
On the image forming apparatus main body side, an engagement member that is engaged with the operation lever is provided,
When the photoconductor unit is mounted on the image forming apparatus main body, the operation lever is engaged with the engagement member, and the protective cover jumps up from the position covering the exposed portion of the photoconductor to the retracted position. Moved and
When the photoconductor unit is removed from the image forming apparatus main body, the operation lever is detached from the engaging member, and the protective cover is moved downward by its own weight from the retracted position to a position covering the exposed portion of the photoconductor. To
An image forming apparatus.   The image forming apparatus according to claim 1, wherein the protective cover blocks an ion flow and an air flow including toner flowing between the charger and the developing unit.

Images