JP2637512B2 - Image forming device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus that forms a toner image on plain paper using an optical image as a signal.

[Conventional technology]

2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic method, a great effort has been made to align a photosensitive drum and a developing device. However, mainly, a gap between a photosensitive drum surface and a developing sleeve, This relates to a so-called development gap, and JP-A-61-153670 also discloses a method of positioning them using the same member.

[Problems to be solved by the invention]

In a recording apparatus using a conventional electrophotographic method, relatively fine precision is not required in positioning in a direction perpendicular to a developing gap direction. However, in the method using the transparent support photosensitive drum, the precision in the vertical direction has a great influence on the image quality, so that there is an intense demand, and this positioning method is a serious problem.

SUMMARY An advantage of some aspects of the invention is to provide an image forming apparatus that can easily perform vertical positioning using a positioning member.

[Means for solving the problem]

An image forming apparatus according to the present invention is configured such that a concave portion that engages with a developing roller shaft of a developing section engages with a pin formed at one end of a latent image carrier unit to keep a developing gap constant, and that an optical device is used. A positioning member having a recess formed so that the light irradiation position can be adjusted relative to the developing unit is attached to the main body, and the developing unit and the latent image carrier unit are supported by the positioning member. It is.

[Action]

In the present invention, the developing gap is ensured by the positioning member, and the accuracy in the vertical direction between the photosensitive drum and the developing unit is further ensured.

〔Example〕

FIG. 1 is a schematic side sectional view showing the structure of one embodiment of the present invention, and FIG. 2 is a perspective view showing the relevant parts of FIG. 1 taken out. In these figures, reference numeral 10 denotes a main body, in which a latent image carrier unit 20, a developing unit 30, a transfer unit 40, a fixing unit 50, a paper feeding unit 60, and a cleaning unit 70 are provided. Hereinafter, each of the above-described units will be sequentially described.

The latent image carrier unit 20 is configured such that an optical printer head 21 as an optical device and a photosensitive drum 29 are integrated. The optical printer head 21 includes a large number of LED chips 22 arranged in a straight line, and a converging light transmitting body 23 extending in parallel with the LED chips.

Side plates 24A and 24B are attached to both sides of the optical printer head 21, and a plurality of shafts (three in the figure) 25 are provided between both side plates 24A and 24B.
A support roller 26 is rotatably provided on both sides of the shaft 25 near the side plate. Side plate 24A
In this case, a mounting piece 24a is integrally formed, and can be fixed to the chassis 11 of the main body 10 by a long hole 24b. Further, fulcrum pins 27 and guide pins 28 are fixed to the outer surfaces of the side plates 24A and 24B (the pins 27 of the side plates 24B are not visible).

The photoconductor drum 29 is formed by laminating a transparent conductive layer and a photoconductive layer on a transparent substrate, and the above-described optical printer head 21 is inserted therein, and each support roller 26 is moved from the inside to the photoconductor drum. 29 is rotatably supported. One of the support rollers 26 is a pressure transfer roller 42 described later.
Is provided at a position opposite to the above. The support roller 26
May be provided not only on both sides of the shaft 25 but also in the center.

The developing unit 30 includes a magnet roller 32 having a magnet roller shaft 33 in a housing 31, a spike regulating plate 34, a stirring screw
35 grades are provided. The housing 31 has a projection 36 and is pulled toward the latent image holding unit 20 by a coil spring 37 stretched between the housing 31 and the projection 12 provided on the chassis 11 of the main body 10.

Reference numeral 13 denotes a positioning member, as is well shown in FIG. 2, in which a concave portion 13a is formed on the end face on the developing unit 30 side, and a magnet roller shaft 33 of a magnet roller 32 is fitted therein. On the opposite side of the concave portion 13a, a concave portion 13b in which the fulcrum pin 27 of the latent image carrier unit 20 fits, a concave portion 13c in which the guide pin 28 similarly fits, and a guide opening 13d are formed by continuous reading. Further, a mounting hole 13e for fixing the chassis 11 or the like of the main body 10 with a screw or the like is formed. 14
Is a drive roller for rotating the photosensitive drum 29.

FIG. 3 is a view for explaining the mounting state of the positioning member 13. The fulcrum pins 27 of the both side plates 24A and 24B are fitted into the concave portions 13b of the left and right positioning members 13, respectively, and the guide pins 28 are inserted into the concave portions 13c.
, And the both side plates 24A, 24B are fixed to the chassis 11 by screws 24c using long holes 24b. At this time, the pointer 24d at the tip of the mounting piece 24a is aligned with the scale 15 of the chassis 11, and is rotated about the fulcrum pin 27, and the guide pin 28 is
By moving along 13c, the latent image carrier unit 20 can perform fine adjustment of the vertical direction, that is, the vertical position. On the other hand, when the magnet roller shaft 33 is fitted into the concave portion 13a, the magnet roller shaft 33 is pushed in the direction of arrow A by the coil spring 37 (FIG. 1). The interval, that is, the developing gap automatically becomes constant.

The transfer unit 40 is configured to be supported such that the pressure transfer roller 41 can rotate around a support shaft 42. Reference numeral 43 denotes a guide plate, which is configured to suck lightly with a suction fan 44 so that unfixed toner on a sheet passing therethrough is not rubbed and disturbed. 45 is a separation nail.

The fixing unit 50 includes a heating roller 51 in which a halogen lamp of about 850 W is installed and is driven to rotate, and a heating roller 51.
The pressure roller 52 is configured to press against
Felt under the 51 is silicone oil impregnated 53
Are provided so as to be pressed by the heating roller 51. 54 is a separation claw, and 55 is a paper discharge roller pair.

A portion including the pressure roller 52 of the transfer unit 40 and the fixing unit 50 and a roller on the driven side (upper side in the figure) of the sheet discharge roller pair 55 are unitized, and are counterclockwise around the support shaft 46. It is configured to be swingable.

The paper feed unit 60 includes a paper feed cassette 61, a paper feed roller 62, a driving roller connected to a motor, and a rotatable driven roller pressed against the driving roller.
Consists of 63.

The cleaning unit 70 includes a cleaning blade 71, and the photosensitive drum that is not transferred by the pressure transfer roller 41.
The toner remaining on the toner 29 is removed by the cleaning unit 70. 80 indicates paper.

 Next, the operation will be described.

A voltage is applied between the magnet roller 32 of the developing unit 30 and the transparent conductive layer of the photoconductor drum 29, and the optical printer head 21 and the converging optical transmitter disposed on the inner surface of the photoconductor drum 29
By irradiating image information by 23, a toner image is formed on the surface of the photosensitive drum 29 corresponding to the image information.

On the other hand, the paper 80 fed by the paper feed roller 62 is conveyed to the transfer position by the register roller pair 63 after timing is taken by the register roller pair 63. In the transfer unit 40, the pressure transfer roller 41 is rotated about the center of the support shaft 42, and the paper 80 is moved by the photosensitive drum 29 and the pressure transfer roller 41.
To transfer the toner image onto the paper 80. The paper 80 onto which the toner image has been transferred is separated from the photosensitive drum 29 by the separation claw 45, and further transported to the fixing unit 50 by the pressure transfer roller 41 and the photosensitive drum 29. The paper 80 onto which the toner image has been transferred in the fixing unit 50 is heated by a heating roller 51 and a pressing roller 52.
, The toner image is fixed, separated by the separation claw 54, and further discharged by the discharge roller pair 55.

〔The invention's effect〕

As described above, the present invention engages with the recess formed in the developing section, which engages with the developing roller shaft, with the pin formed at one end of the latent image carrier unit, to keep the developing gap constant, and to use the optical device. Since a positioning member having a recess formed so that the light irradiation position can be relatively adjusted with respect to the developing unit is provided in the main body, and the developing unit and the photosensitive drum are supported by the positioning member, The position of the developing gap between the photosensitive drum and the developing unit is of course determined by the positioning member.
Since the positional accuracy in the vertical direction can be maintained, dimensional control is easy, and reliability is improved. Further, there is an advantage that the light irradiation position on the developing roller can be easily and optimally set by the positioning member.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view showing an embodiment of the present invention, FIG. 2 is a perspective view showing a main part of FIG. 1, and FIG. 3 is an explanatory view of a state of mounting a positioning member. In the figure, 10 is a main body, 11 is a chassis, 12 is a projection, 20 is a latent image carrier unit, 21 is an optical printer head, 22 is an LED chip, 23 is a converging light transmitter, 24A and 24B are side plates, and 25 is Axis, 26
Is a support roller, 27 is a fulcrum pin, 28 is a guide pin, 29 is a photosensitive drum, 30 is a developing unit, 31 is a housing, 32 is a magnet roller, 33 is a magnet roller shaft, 34 is a spike restricting plate, 35 is Stirring screw, 36 is a protrusion, 37 is a coil spring, 40 is a transfer section, 41 is a pressure transfer roller, 42 is a support shaft, 50 is a fixing section, 51
Is a heating roller, 52 is a pressure roller, 53 is a felt, 54 is a separation claw, 55 is a paper discharge roller pair, 60 is a paper feed unit, 61 is a paper feed cassette, 62 is a paper feed roller, 63 is a register roller pair, 80 is paper.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaru Ozawa 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Fumihiko Hamada 2-18-18 Keihanhondori, Moriguchi-shi, Osaka (72) Inventor Kenpachi Shiraki 2-18-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (1)

(57) [Claims] 1. A latent image carrier in which a photosensitive drum having a transparent conductive layer and a photoconductive layer laminated on a transparent substrate and an optical device for irradiating light selected from the transparent substrate side are unitized. In an image forming apparatus having a unit and a developing unit arranged corresponding to the optical device via the photosensitive drum, a concave portion which engages with a developing roller shaft of the developing unit; A positioning member formed with a recess that is engaged with a pin formed at one end, maintains a developing gap constant, and allows a light irradiation position of the optical device to be adjustable relative to the developing unit. Wherein the developing unit and the latent image carrier unit are supported by the positioning member.