JP4018594B2 - Photosensitive drum unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photosensitive drum unit provided in an electrophotographic image forming apparatus such as a copying machine, a facsimile machine, and a printer, and more specifically, a photosensitive drum unit applied to a photosensitive drum with a built-in heater. About.
[0002]
[Prior art]
In an electrophotographic image forming apparatus typified by a copying machine, the surface of a rotating photosensitive drum is uniformly charged to a predetermined polarity and exposed to light based on predetermined image information for static exposure. An electrostatic latent image is formed, and the electrostatic latent image is developed by a developing device filled with charged toner to form a toner image on the drum surface. The toner image is then transferred to a transfer roller or a transfer corona charge. The image is transferred to the transfer paper using an electrostatic force, transferred to the transfer paper using the electrostatic force, and the transfer paper onto which the toner image has been transferred is introduced into the fixing device, and the toner image is fixed on the transfer paper surface by heat and pressure. Done. On the other hand, after the transfer of the toner image is completed, the toner remaining on the surface of the photosensitive drum is cleaned by a cleaning device, and further, static elimination is performed as necessary. Thus, one cycle of the image forming process is completed, and the next image is completed. Formation takes place.
[0003]
As a photosensitive drum used in the image forming apparatus as described above, there is a type having a built-in heater. For example, a silicon photosensitive drum having an amorphous silicon photosensitive layer has a property that when a small amount of moisture is present on the surface, the surface charge flows and a so-called image flow occurs, so a heater is provided inside the drum. The image forming process is carried out while heating to a suitable temperature.
[0004]
In the above-described photosensitive drum with a built-in heater, since it is necessary to supply electric power to the heater provided inside the rotating photosensitive drum, various power feeding mechanisms have been proposed (for example, Patent Document 1, Patent Document 1). 2).
[0005]
[Patent Document 1]
Japanese Patent No. 2544237 [Patent Document 2]
JP-A-11-40305 [0006]
[Problems to be solved by the invention]
However, in the power supply method of Patent Document 1, a plurality of electrode plates are provided side by side along the drum axis direction at the end of the photosensitive drum, and electrode terminals are rubbed against the electrode plates on the image forming apparatus main body. Since it is attached, there is a drawback that the space of the electrode plate is increased and the width of the apparatus is increased. There is also a problem that it is not easy to remove the electrode terminal from the apparatus main body.
[0007]
Further, the power feeding method of Patent Document 2 is such that an electrode terminal is provided on the photosensitive drum side, and this electrode terminal is pressed against an electrode plate provided on the image forming apparatus main body side. There is a drawback in that the electrode terminal is damaged when being mounted on the main body or when the photosensitive drum mounted on the main body of the image forming apparatus is removed upward.
[0008]
Accordingly, it is an object of the present invention to easily supply power to the heater provided in the photosensitive drum without increasing the size of the image forming apparatus, and to attach / detach the photosensitive drum to / from the image forming apparatus main body. An object of the present invention is to provide a photosensitive drum unit capable of effectively preventing damage to electrode terminals and the like.
[0009]
[Means for Solving the Problems]
According to the present invention, a photosensitive drum provided with a heater inside, and an electrically insulating drum that is fitted in each of both ends of the photosensitive drum and has a rotation shaft and can rotate integrally with the photosensitive drum. A flange and a rotation shaft formed integrally with the drum flange are held so as to be rotatable relative to each other, and a distance between the developing roller and the photosensitive drum arranged side by side on the photosensitive drum is kept constant. A large-diameter and small-diameter ring-shaped electrode plate electrically connected to the heater is concentrically fixed to the outer surface of the drum flange in a non-contact manner on the outer surface of the drum flange. A photosensitive drum unit is provided in which a pair of electrode terminals are provided on the inner surface of the adjustment plate so as to be able to slide on the large-diameter or small-diameter ring-shaped electrode plates, respectively.
[0010]
In the image forming apparatus, a developing device is disposed around the photosensitive drum, and the developing device is provided with a developing roller facing the photosensitive drum. That is, since development is performed by attaching charged toner to the electrostatic latent image formed on the drum surface by the developing roller, it is necessary to set the developing roller and the photosensitive drum at a constant interval. It becomes. In order to adjust the interval, an interval adjusting plate is attached to the rotating shaft of the drum flange fitted to the end of the photosensitive drum. In the photosensitive drum unit of the present invention, electrode terminals are provided on the interval adjusting plate, and electrode plates are provided concentrically on a drum flange fitted in the photosensitive drum. Accordingly, the mounting and removal of the photosensitive drum from the image forming apparatus main body is performed while the interval adjusting plate is attached to the drum flange, so that the electrode terminals are damaged during the mounting and removal. There is no fear, and since the electrode plate is provided concentrically on the drum flange, a useless space by the electrode plate can be avoided. Furthermore, the electrode terminal can be easily detached from the interval adjusting plate.
[0011]
In the present invention,
1. A cylindrical holder in which the electrode terminal is accommodated is fixed to the inner surface of the distance adjusting plate, and the electrode terminal is urged by an elastic member so that the tip of the electrode terminal protrudes from the cylindrical holder. ,
2. The photosensitive drum is a silicon photosensitive drum provided with an amorphous silicon photosensitive layer;
Is preferred.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on specific examples shown in the accompanying drawings.
FIG. 1 is a diagram for explaining the function of the interval adjusting plate in the photosensitive drum unit of the present invention.
FIG. 2 is a plan cross-sectional view of the main part of the photosensitive drum unit of the present invention,
FIG. 3 is a front view of a drum flange used in the photosensitive drum unit of FIG.
FIG. 4 is a view showing a structure of a holder provided on the interval adjusting plate in the photosensitive drum unit of FIG.
[0013]
First, referring to FIG. 1, a photosensitive drum 1 attached to the main body of the image forming apparatus has a developing device generally indicated by 2 in the vicinity thereof (in FIG. 1, the developing device is shown in an exploded perspective view). Is placed). The developing device 2 includes a developing roller 2 a for supplying charged toner to a developing area on the surface of the photosensitive drum 1, and the developing roller 2 a is disposed at a constant interval with respect to the photosensitive drum 1. Must be. For this purpose, the interval adjusting plate 3 is used.
[0014]
That is, the interval adjusting plate 3 is attached to the rotating shaft 5a of the drum flange 5 fitted in the side end portion of the photosensitive drum 1, and has a notch 7 for positioning and a handle portion 8. . The notch 7 fixes the position of the gap adjusting plate 3 when it is attached to the main body of the image forming apparatus, and is held unrotatable. In addition, the handle unit 8 can be easily attached to and detached from the image forming apparatus main body for each photosensitive drum 1.
[0015]
On the other hand, protrusions 2b and 2b are provided on the side surface of the housing of the developing device 2, and when the interval adjusting plate 3 is attached to the main body of the image forming apparatus, the side surface of the interval adjusting plate 3 contacts the protrusions 2b and 2b. As a result, the photosensitive drum 1 and the developing roller 2a are held at a constant interval.
[0016]
Referring to FIG. 2, the photosensitive drum unit of the present invention includes a photosensitive drum 1, a drum flange 5 that is fitted into a side end portion of the photosensitive drum 1 and rotates integrally with the drum 1, and the above-described interval. The adjustment plate 3 is constituted.
[0017]
As the photosensitive drum 1, a silicon photosensitive drum in which an amorphous silicon photosensitive layer is formed on the surface of a conductive element tube such as aluminum is preferably used. This is because, as already described, in this type of photosensitive drum, removal of moisture by heating or heating is required to prevent image flow. Of course, other types of photosensitive drums can be used to prevent condensation.
[0018]
The internal structure of the photosensitive drum 1 is known per se and has the same structure as that disclosed in, for example, Japanese Patent No. 2544237. For example, a cylindrical heater 12 that operates in response to an electrical signal from a predetermined control board 10 is provided inside the drum 1 so as to rotate integrally with the drum flange 5. The thermistor 14 is connected. That is, a temperature detection signal from the thermistor 14 is transmitted to the control board 10 and the operation of the heater 12 is controlled according to the detected temperature.
[0019]
In the present invention, the drum flange 5 fitted in the side end portion of the photosensitive drum 1 is made of an electrically insulating material such as resin, and an annular protrusion centering on the rotating shaft 5a is formed on the outer surface thereof. 20 is formed, and a small-diameter ring-shaped electrode plate (hereinafter referred to as a first electrode plate) 22 is fixed to the inner side of the annular protrusion 20 with an adhesive or the like. A large-diameter ring-shaped electrode plate (hereinafter referred to as a second electrode plate) 24 is fixed with an adhesive or the like. That is, as shown in FIG. 3 which shows a front view of the drum flange 5, the first electrode plate 22 and the second electrode plate 24 are formed concentrically around the rotation shaft 5a. Yes.
[0020]
As is clear from FIG. 2, the first electrode plate 22 and the second electrode plate 24 are respectively connected to the control substrate 10 inside the drum 1, and the heaters are connected via the electrode plates 22 and 24. 12 is energized.
[0021]
The rotating shaft 5a of the drum flange 5 is fitted into the bearing 30 provided on the interval adjusting plate 3 described above, and the drum flange 5 and the interval adjusting plate 3 are relatively rotatable. That is, in the photosensitive drum unit, the photosensitive drum 1 is positioned at a constant interval from the developing roller 2a of the developing device 2 described above by attaching the interval adjusting plate 3 to the image forming apparatus main body and fixing the position thereof. Although not shown, a normal drum flange having only a rotating shaft is fitted into the other side end of the drum 1, and the rotating shaft is rotatably held by the main body of the image forming apparatus. The drum 1 can be driven and rotated by transmitting the drive from a predetermined drive mechanism to the shaft.
[0022]
In the present invention, as shown in FIG. 2, a first holder 32 and a second holder 33 are provided on the inner surface of the interval adjusting plate 3 fixed in position within the image forming apparatus main body. Electrode terminals 35 are provided in the holders 32 and 33, respectively. That is, one of these electrode terminals 35 and 35 is connected to a power source 37, and the electrode terminal 35 rubs against the first electrode plate 22 or the second electrode plate 24, respectively. It is provided as follows.
[0023]
That is, in FIG. 4 showing the structure of the holder 32 (33), the holder 32 (33) includes a support substrate 40, a cylindrical portion 42 formed on one surface of the support substrate 40, and the support substrate 40. A foot portion 44 formed on the other surface, and an opening 46 is formed between the foot portions 44. In other words, the holder 32 (33) is fixed to the interval adjusting plate 3 by fitting the foot portion 44 to the wall of the interval adjusting plate 3.
[0024]
An electrode terminal 35 is accommodated in the holder 32 (33), and this electrode terminal 35 is urged outward by an elastic member 46 supported by the support substrate 40. Further, a claw 48 is formed at the upper end of the cylindrical portion 42, and the electrode terminal 35 is stably held in the cylindrical portion 42 by the claw 48.
[0025]
As is apparent from FIG. 4, the upper end surface 35a of the electrode terminal 35 is a curved surface, protrudes outward from the upper end of the cylindrical portion 42, and the upper end surface 35a is rotated by elastic force. It is configured to come into contact with 22 or 24 and rub. A wiring conductor 50 is drawn out from the electrode terminal 35, and a connector 52 is connected to the tip of the wiring conductor 50. The connector 52 is connected to a connector (not shown) provided in the image forming apparatus main body, and electric power is input to the electrode terminal 35 via the connector 52, and the first and second electrode plates 22 and 24 are used. Electric power is supplied to the heater 12 and the thermistor 14 via the control board 10.
[0026]
【The invention's effect】
As described above, according to the present invention, since the concentric electrode plates 22 and 24 are provided on the drum flange 5 fitted in the photosensitive drum 1, it is possible to prevent generation of useless space due to the electrode plates. And an increase in the size of the image forming apparatus can be avoided.
[0027]
In addition, power is supplied to the electrode plates 22 and 24 that supply power to the heater 12 inside the drum 1 through electrode terminals 35 provided on the interval adjusting plate 3 side. That is, the electrode terminal 35 slidably rubs against the electrode plates 22 and 24 provided on the rotating drum flange 5, but the image of the drum photosensitive drum 1 is maintained with the gap adjusting plate 3 attached to the flange 5. Attachment to the forming apparatus main body and removal from the image forming apparatus main body are performed. Therefore, there is no possibility of damaging the electrode terminal during the mounting and removal.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a function of a gap adjusting plate used in a photosensitive drum unit of the present invention.
FIG. 2 is a plan cross-sectional view showing the main part of the photosensitive drum unit of the present invention.
3 is a front view of a drum flange used in the photosensitive drum unit of FIG. 2;
4 is a view showing a structure of a holder provided on a gap adjusting plate in the photosensitive drum unit of FIG. 2;
[Explanation of symbols]
1: Photosensitive drum 3: Space adjustment plate 5: Drum flange 10: Control board 12: Heater 14: Thermistor 22: Small-diameter electrode plate (first electrode plate)
24: Large-diameter electrode plate (second electrode plate)
35: Electrode terminal

Claims (3)

A photosensitive drum having a heater therein; an electrically insulating drum flange that is fitted in each of both ends of the photosensitive drum and has a rotation shaft; and is rotatable integrally with the photosensitive drum; and the drum flange integrally is relatively rotatably supported to one of the formed the rotary shaft consists of a gap adjusting plate for holding juxtaposed to the photoreceptor drum was a developing roller spacing of the photoreceptor drum constant A large-diameter and a small-diameter ring-shaped electrode plate electrically connected to the heater is fixed concentrically and in a non-contact manner on the outer surface of the drum flange, and on the inner surface of the gap adjusting plate, A photosensitive drum unit, wherein a pair of electrode terminals are provided so as to be able to slide on the large-diameter or small-diameter ring-shaped electrode plates, respectively.   A cylindrical holder in which the electrode terminal is accommodated is fixed to an inner surface of the interval adjusting plate, and the electrode terminal is urged by an elastic member so that a tip of the electrode terminal protrudes from the cylindrical holder. Item 2. The photosensitive drum unit according to Item 1.   The photosensitive drum unit according to claim 1, wherein the photosensitive drum is a silicon photosensitive drum having an amorphous silicon photosensitive layer.

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