JP3142104B2 - Electrophotographic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus such as a laser printer having a photoconductor and a charging device (photoconductor charger, transfer device).

[0002]

2. Description of the Related Art FIGS. 3 and 4 show a conventional structure of an electrophotographic apparatus. In FIG. 3, reference numeral 10 denotes a photoreceptor, which is rotated in a clockwise direction (direction of arrow A) in forming an image. Reference numeral 5 denotes a photoconductor charger, 6 denotes an exposure device, and 7 denotes a developing device.

The photoreceptor 10 is first charged uniformly by a photoreceptor charger 5 and then exposed by a laser beam B irradiated from an exposure device 6 based on print data to form an electrostatic latent image. The electrostatic latent image is developed by the developing device 7 to be a toner image, and then transferred by the transfer device 20 to a transfer material (paper or the like) sent from a paper supply unit (not shown).

Here, as shown in FIG. 4, the photoconductor 10 includes a drum 11 and a flange (12P, 17), and is rotatably mounted on a conductive shaft 19. The drum 11 is cylindrical and made of metal (for example, aluminum), and has a photosensitive layer formed on the surface. The flanges (12P, 17) are both formed of an insulating material, are press-fitted into the end of the drum 11, and support the drum 11 rotatably around the conductive shaft 19.

One of the two flanges (12P, 17) has a gear flange 12P having a tooth profile.
A gear train (not shown) is connected to the gear flange 12P to transmit power.

The above-mentioned drum 11 needs to be grounded (or an electric bias is applied). Therefore, the inner surface of the drum 11 and the conductive shaft 19 may be electrically connected via the connecting member 18 as shown in FIG. The connecting member 18 is connected to a flange (12
P), one end is pressed against the inner surface of the drum 11 and the other end is slidably pressed against the outer peripheral surface of the conductive shaft 19.

In FIG. 5, reference numeral 31 denotes a position regulating member.
The flange (12P, 17) is interposed between the frame 9 supporting the conductive shaft 19 and each flange (12P, 17).
2P, 17) to regulate the axial position of the photoconductor 10 by engaging with the end face of each bearing portion (14, 17a).

The transfer unit 20 is disposed below the photoconductor 10 so that the ends (101 and 201, 10r and 20r) are aligned with the photoconductor 10, and a power supply provided at one end. A high voltage (for example, 4.5 KV) is applied from the unit 25. Here, the transfer device 20
Is a wire type, and a power supply unit 25 includes a connecting portion 26 connected to the wire 22 stretched over the main body case 21,
An external contact 27 electrically connected to the connecting portion 26 and connected to a high-voltage power supply 29 is provided.

The photoreceptor charger 5, which is a kind of a charging device, has the same configuration as the transfer device 20, together with the transfer device 20 described above. That is, the transfer unit 20 includes components having the same configuration as the main body case 21, the wire 22, the power supply unit 25, the connection unit 26, the external contact 27, and the like.

As described above, in a lower-pass type electrophotographic apparatus for transferring a toner image onto a sheet passing below the photoconductor 10, the photoconductor charger 5 is disposed above the photoconductor 10 and transferred below. A device 20 is provided, and the sheet is
In the upper-pass type electrophotographic apparatus that transfers a toner image through the upper part of the photoconductor, a transfer unit (20) is provided above the photoconductor 10, and a photoconductor charger (5) is provided below the photoconductor.

[0011]

In the above-described electrophotographic apparatus, the connecting member 18 having a complicated shape must be mounted in the drum 11 of the photoreceptor 10, so that the assembling is troublesome and the cost is high. It tends to be. Also, the pressure contact condition between the connecting member 18 and the conductive shaft 19 is adjusted so that the drum 11 and the conductive shaft 19 are reliably electrically connected without increasing the rotational resistance of the photoconductor 10. It also takes time.

In order to solve the above problem, the present applicant has formed a flange (12P) from a conductive resin member, and electrically connected the drum 11 and the conductive shaft 19 via the flange (12P). (Japanese Utility Model Laid-Open No. 3-63173).

In such an image forming drum device, the photosensitive member 1
The smooth rotation of 0 is assured, and the photoconductor 10 can be reliably grounded (or an electric bias is applied).
However, when used for a long period of time beyond the normal use period, transfer failure may occur, and there is a problem from the viewpoint of further improving reliability and print quality.

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to reliably ground a photoreceptor under smooth rotation assurance, and to prevent the occurrence of transfer failure even during long-term use. An object of the present invention is to provide an electrophotographic apparatus capable of achieving high-quality printing by using an electrophotographic apparatus.

[0015]

SUMMARY OF THE INVENTION According to the present invention, transfer failure may occur due to long-term use because the conductive flange is worn by rubbing against the position regulating member, and the conductive powder or the like generated by the wear is used. Is a charging device (transfer unit, photoreceptor charger)
It was created based on the experimental result that it was caused by dropping on the power supply part of the No.1 and causing an electric short, a leak and the like.

That is, the present invention provides a photosensitive member having a conductive flange and driven to rotate, a position regulating member which engages with the conductive flange of the photosensitive member to regulate the axial position of the photosensitive member, A charging device provided below the photoconductor so that the photoconductor and the end are aligned with each other and to which a high voltage is applied from a power supply unit provided at one end; and a conductive flange for the transfer device. The power supply unit is provided so as to be aligned with an end opposite to the end provided with the power supply unit.

[0017]

[0018]

In the present invention having the above structure, the photosensitive member is grounded (or an electric bias is applied) via the conductive flange without using the connecting member (18) as in the conventional example (FIG. 5). Therefore, the photoreceptor can be surely grounded (or applied with an electrical bias) while ensuring smooth rotation.

Further, since the conductive flange is provided so as to be aligned with the end of the charging device (transfer device, photosensitive member charger) opposite to the end where the power supply portion is provided, it is assumed that the conductive flange is provided. Even if the conductive flange rubs against the position regulating member due to long-term use and wears, and the conductive wear powder may drop, the wear powder may adhere to the power supply portion and cause a leak or the like. Nothing happens. As a result, high quality printing can be achieved by preventing transfer failure from occurring even for long-term use.

[0020]

[0021]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) The present electrophotographic apparatus is of a lower pass type.
As shown in FIG. 1, the basic configuration is the same as that of the conventional example (FIGS. 3 to 5), but a conductive flange (12) is provided with a power supply portion 25 of a transfer device 20 as a charging device. The end (20l) is arranged so as to be aligned with the end (20r) opposite to the end (20l). Components common to the conventional example (FIGS. 3 to 5) are denoted by the same reference numerals.
The description is simplified or omitted.

The conductive gear flange 12 serving as a conductive flange is made of a conductive resin material (in this embodiment, a conductive polyacetal resin of a carbon dispersion type), and is larger than the inner diameter of the drum 11 constituting the photoreceptor 10. Drum fitting part 13 and bearing part 14 for receiving conductive shaft 19
And a drive gear unit 1 that receives power from a gear train (not shown)
5 are integrally formed. The conductive gear flange 12 elastically deforms the drum fitting portion 13 and press-fits it into the right end of the drum 11 in FIG.
1 is attached. The conductive shaft 19 is formed of a round bar in which the surface of a mild steel bar is plated with nickel.

Next, the operation of this embodiment will be described. The photoconductor 10 is connected to a connecting member (1) as in the conventional example (FIG. 5).
8) It is electrically contacted with the conductive shaft 19 via the conductive gear flange 12 without using. Therefore, the photoreceptor 10 can be reliably grounded (or applied with an electrical bias) while ensuring smooth rotation.

Further, since the conductive gear flange 12 is disposed so as to be aligned with the end 20r of the transfer unit 20 opposite to the end 201 provided with the power supply unit 25, the conductive gear flange 12 may be conductive for a long time. Even if the conductive gear flange 12 rubs against the position regulating member 31 and wears, and the conductive wear powder may fall, the wear powder may adhere to the power supply portion 25 and cause a leak or the like. Nothing happens.

Thus, according to the first embodiment, the conductive gear flange 12 is disposed so as to be aligned with the end 20r of the transfer unit 20 opposite to the end 201 provided with the power supply unit 25. With such a configuration, the photosensitive member 10 can be reliably grounded under the assurance of a smooth rotation, and a high-quality printing can be achieved by preventing a transfer failure from occurring even during long-term use. be able to.

When the present invention is applied to an upper-pass type electrophotographic apparatus, a photoreceptor charger (not shown) as a charging device is provided below the photoreceptor 10 in place of the transfer device 20. Therefore, the conductive flange (12) is disposed so as to be aligned with the end of the photoconductor charger opposite to the end where the power supply unit is provided.

Although the conductive flange is formed of the conductive gear flange 12, the other flange 17 may be formed of a conductive material, and the conductive flange may be formed by the flange 17.

(Second Embodiment) A second embodiment is shown in FIG. The electrophotographic apparatus according to the second embodiment has a configuration in which an insulating member (41) is interposed between the conductive flange (12) and the position regulating member 31. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be simplified or omitted.

In this embodiment, the insulating member is formed by the insulating cap 41. The insulating cap 41 is
The photoconductor 10 is configured so that it can be mounted on the left end in FIG. 2 of the bearing portion 14 of the conductive gear flange 12 of the photoconductor 10.

With such a configuration, the conductive gear flange 1
Since the insulating cap 41 is interposed between 2 and the position regulating member 31, no abrasion powder is generated from the conductive gear flange 12 even when used for a long time. As a result, the photoreceptor 10 can be reliably grounded or the like under the assurance of smooth rotation, and furthermore, it is possible to achieve high quality printing by preventing occurrence of transfer failure even for long-term use. . In addition, the arrangement position of the conductive gear flange 12 can be freely selected, and the degree of freedom in layout is expanded.

In the present invention, the flanges (12, 17) at both ends of the drum 11 are used without using the conductive shaft 19.
Can also be applied to a photoreceptor configured to rotatably support. In such a photoconductor, ground (electric bias is applied) through the conductive flange (12).

[0032]

According to the present invention, since the conductive flange is arranged so as to be aligned with the end of the charging device opposite to the end where the power supply portion is provided, the photosensitive member can be used. Grounding can be reliably performed under the assurance of smooth rotation, and high-quality printing can be achieved by preventing the occurrence of transfer failure even during long-term use.

[0033]

[Brief description of the drawings]

FIG. 1 is a side sectional view for explaining a first embodiment of the present invention.

FIG. 2 is a side sectional view for explaining a second embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration of an electrophotographic apparatus.

FIG. 4 is an exploded perspective view for explaining a conventional configuration of a photoconductor.

FIG. 5 is a side sectional view for explaining another conventional example of a photoconductor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Photoconductor 11 Drum 12 Conductive gear flange (conductive flange) 20 Transfer device (charging device) 25 Power supply part 31 Position regulating member 41 Insulating cap (insulating member)

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tadao Kamano 570, Oni-cho, Oni-cho, Tata-gun, Shizuoka Prefecture Tokyo Electric Co., Ltd. In the Ohito Plant (56) References JP-A-61-114282 (JP, A) JP-A-60-112085 (JP, A) Japanese Utility Model Sho-56-52771 (JP, U) (58) Fields investigated (Int. . Cl ^7, DB name) G03G 15/00 550 G03G 21/00 350 - 352 G03G 15/02 G03G 15/16 G03G 21/16 - 21/18

Claims (1)

(57) [Claims] A photosensitive member having a conductive flange and driven to rotate; a position regulating member which engages with the conductive flange of the photosensitive member to regulate an axial position of the photosensitive member; A charging device provided so that the photosensitive member and the end portions thereof are aligned with each other, and to which a high voltage is applied from a power supply portion provided at one end portion, a conductive flange provided, and a power supply portion of the charging device provided. An electrophotographic apparatus, wherein the electrophotographic apparatus is arranged so as to be aligned with an end opposite to the end provided.