JPH02214881A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the degrading of a toner image quality by providing a means to mechanically lower the adhering ability of photosensitive body to the photosensitive body, in the vicinity of the upper stream side of a toner developing and cleaning means. CONSTITUTION:A following roller 4, as the adhering ability lowering means to mechanically lower the adhering ability to the photosensitive body 2 of the untransferred residue toner adhered to the surface of the photosensitive body 2, is provided in the vicinity of the upper stream side of the toner developing and cleaning means 25. Then a brush 39 is planted in the periphery of the central part of the rotating shaft 38 of the following roller 4, and is constituted to abut on the photosensitive body 2. Therefore, the untransferred residue toner B which is not transferred on a recording paper 18 is abraded off by the rotating brush 39, made to be in a floating condition, and is magnetically sunctioned by a magnetic roller 27. Thus, the residue toner is surely eliminated from the photosensitive body and the degrading of the printing quality can be prevented.

Description

Detailed Description of the Invention B) Industrial Field of Application The present invention relates to an image forming apparatus of a type in which, for example, an exposure light source is arranged inside a photoreceptor drum and the photoreceptor drum is exposed from inside. .

(b) Prior art This type of image forming apparatus is known, for example, from Japanese Patent Application Laid-Open No. 58-15395.
This is shown in Publication No. 7. In the apparatus disclosed in this publication, untransferred residual toner on the photoreceptor is removed and collected by a toner developing and cleaning means.

(C) Problems to be Solved by the Invention As mentioned above, in the conventional technology, the toner developing/cleaning means attempts to remove the toner (residual). It is possible to perform sufficient cleaning by using a toner developing and cleaning means.

However, as the frequency of use of the apparatus increases, scratches are inevitably formed on the surface of the photoreceptor due to recording paper and the like.

In this way, when the surface condition of the photoreceptor becomes grainy, the adhesion of the residual toner to the surface of the photoreceptor is strengthened, making it impossible to sufficiently clean the toner developing and cleaning means alone. Therefore, residual toner caused by poor cleaning may deteriorate the quality of toner images.

(d) Means for Solving the Problems The present invention provides a photoconductor that includes a transparent substrate, a transparent conductive layer and a photoconductor layer formed on the substrate, and moves in a predetermined direction, and a transparent substrate of the photoconductor. an exposure light source for exposing the photoconductor layer through the transparent substrate and the transparent conductive layer; An adhesion force reducing means is provided near the upstream side of the toner developing/cleaning means for mechanically reducing the adhesion force of untransferred residual toner adhering to the surface of the photoreceptor to the photoreceptor. It is characterized by the fact that

(e) Function: In the present invention, the adhesion force of untransferred residual l/toner adhering to the surface of the photoreceptor to the photoreceptor is mechanically reduced near the upstream side of the developing/cleaning means. Since the adhesive force reducing means is provided, the residual toner whose adhesion force has decreased is reliably removed from the photoreceptor by the L/ner developing/leaning means.

(f) Embodiment FIG. 1 is a schematic portrait view of an LED printer as an embodiment of the present invention, FIG. 2 is a partially sectional perspective view, and FIGS. 3 and 4 are side views of main parts. .

In these figures, (1) is an apparatus main body, and a photosensitive drum (2) is rotatably supported inside the apparatus main body (1). This photoreceptor drum (2) is a conventional surface forming device (
For example, as in JP-A-58-153957), it consists of a cylindrical transparent glass substrate, and a transparent conductive layer and a photoconductor layer that are sequentially laminated on the outer peripheral side wall of the glass substrate.

The photosensitive drum (2) has one driving roller (3) and two driven rollers [4] arranged around it.
(5) (see FIGS. 1 and 4) and is rotatably held. In addition, these rollers (3) (41 (5
) are in contact with the non-image forming area where only the transparent conductive layer is formed near both ends of the photoreceptor drum (2).

The driven roller (4) is made of conductive rubber and is grounded via its rotating shaft.

Inside the photoreceptor drum (2), an LED holder (6) extending in the axial direction and the LED holder (6) are provided.
) is inserted in the horizontal direction as an exposure device (9) as an exposure light source, which is composed of an LED array (7) and a short focus lens array (8) mounted on the lens and closely arranged in the axial direction.

One end of the LED holder (6) is fixed to one side wall (10) of the chassis of the device main body (1) with a thread 11). The other side wall (12) of the chassis is provided with an opening (13) through which the photoreceptor drum (2) can be inserted and removed in its axial direction, and a mounting plate (14) is provided in the opening (13). It is removably fixed with a thread 15). There are two wooden protrusions (1G) on the inside of the mounting plate (14).
) is provided in a protruding manner, and the other end of the LED boulder (6) is provided with a holding hole (17) into which the protrusion (16) can be inserted.

Note that the photosensitive drum (2) has a positioning member (36).
(37) determines its axial position.

In FIG. 1, a paper feed cassette (19) in which recording paper (18) is loaded is located at the lower right of the main body (1) of the apparatus.
It is inserted so that it can be inserted and removed horizontally. A recording paper holding plate (20) is attached to the bottom of this paper feed cassette (19) so as to be able to swing freely in the vertical direction, and the recording paper (18) is stacked on this recording paper holding plate (20). be done.

A paper feed roller (21) is provided above the downstream end of the paper feed cassette (19) of the apparatus main body (1), and the recording paper holding plate (20) is provided below the paper feed roller (21). A lifting lever (22) biased clockwise by a spring (not shown) is provided for lifting the.

Therefore, when the paper feed cassette (19) is inserted horizontally from the right side of the apparatus main body (1), the recording paper holding plate (20)
is lifted by the lifting lever (22), and the uppermost recording paper (18) is brought into pressure contact with the paper feed roller (21).

On the downstream side of the paper feed roller (21) along the paper feeding direction, the recording paper (18) that has been fed by the paper feed roller (21) is stopped at a certain timing. A pair of registration rollers (231 (24)) for refeeding is provided.

A toner developing/cleaning device (25) is provided outside the photosensitive drum (2) at a location facing the short focus lens array (8) of the exposure device (9).

The toner developing/cleaning device (25) is attached to the chassis of the device main body (1) by a coil spring (not shown) so as to be always pulled toward the photosensitive drum (2). □The toner supplied into the developer chamber of the developing device (25) is transported to the magnet roller (27) by the transport screw (26). The transported toner is formed as a magnetic brush on the circumference of the magnet roller (27). The height of the magnetic brush, that is, the height of the spike is adjusted by a spike regulating plate (28), and is transferred to the part facing the photoreceptor drum (2) according to the rotation of the magnet roller (27). be done. That is, toner is conveyed between the magnetic roller (27) and the photoconductor layer of the photoreceptor drum (2).

On the other hand, although not shown, for example, 200
(2) DC voltage is applied. The photoconductor layer of the photosensitive drum (2) facing the magnet roller (27) is then irradiated with exposure light according to the image information by the LED array (7) and the short focus lens array (8). ing. In the portion of the photoconductor layer that has received the exposure light, its resistance value decreases, and therefore a current flows between the magnet roller (27) and the transparent conductive layer due to the above-mentioned voltage. Therefore, the toner present in that area is charged by the current. On the other hand. In the unexposed areas, the resistance of the photoconductor layer remains high and no current flows, so the toner is hardly charged. Further, on the exposed photoconductor drum (2), that is, the photoconductor layer, a latent image charge having a polarity opposite to that of the toner is generated by the above-mentioned current, and the charged toner is transferred to the photoconductor drum (2). ) is attracted to the surface of the photoconductor layer by electrostatic force. In this way, the LED array (7
), a toner image (TA) is formed on the photoreceptor drum (2) by the developing device (25).

The registration I/roller pair +231 (downstream side of 241)
On the left), a transfer roller (29) for transferring the toner image (TA) on the photoreceptor drum (2) onto the recording paper (18) is in pressure contact with the lower part of the photoreceptor drum (2). There is.

On the downstream side (left side) of the transfer roller (29), recording paper (1
8) A heat roller pair (30) (311) is provided for fixing the toner image transferred thereon by heat and pressure.A separating claw (32) is attached to the upper heat roller (30). ing.

The recording paper (18) fixed by the heat roller pair <30) (31) is made a U-turn through the paper feed path (33), and is discharged by the paper discharge roller pair (34) (35).

The recording paper (18) discharged by the pair of paper discharge rollers (34) [35] is discharged to the upper part of the apparatus main body (1).

The shield (39) is configured to abut against the photoreceptor (2).

Therefore, the untransferred residual toner (TB) that is not transferred to the recording paper (18) is rubbed by the rotating brush (39), and its adhesion to the photosensitive drum (2) is reduced, resulting in a floating state.

Then, the floating residual toner (TB) is magnetically attracted to the magnet roller (27) and the photosensitive drum (27)
).

(G) Effects of the Invention In the present invention, an attachment is provided near the upstream side of the toner developing/cleaning means to mechanically reduce the adhesion force of untransferred residual toner adhering to the surface of the photoreceptor to the photoreceptor. Since the adhesive force reducing means is provided, even if the surface of the photoreceptor becomes rough, residual toner whose adhesion force has decreased is reliably removed from the photoreceptor by the toner developing and cleaning means.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, FIG. 2 is a partially enlarged sectional view, FIG. 3 is a plan view of the main part, and FIG. 4 is a side view of the main part. (1)...Device body, (2)...Photoconductor drum, (
3)... Drive roller, (4) (51... Followed roller, (6)... LED holder, (7)... LED array, (8)... Short focus lens row, (9 )...Exposure device, (1θ)...-One side wall, (12)...Other side wall, (13)...Opening, (14)...Mounting plate,
(1B) Recording paper, (25) Toner developing and cleaning device, (27) Magnet roller, (3
9)...Brush.

Claims (1)

[Scope of Claims] 1. A photoreceptor that includes a transparent substrate, a transparent conductive layer and a photoconductor layer formed thereon, and that moves in a predetermined direction, and a transparent substrate that is disposed on the transparent substrate side of the photoreceptor. and an exposure light source for exposing the photoconductor layer through the transparent conductive layer, and a toner developing/cleaning unit provided at a location facing the exposure light source with the photoconductor sandwiched therebetween, or at a location downstream from the said location. In an image forming apparatus comprising a transfer means for transferring a toner image onto a recording paper, a portion of untransferred residual toner adhering to the surface of the photoreceptor is removed near the upstream side of the toner developing/cleaning means. An image forming apparatus characterized by comprising an adhesion force reducing means for mechanically reducing the adhesion force to the photoreceptor. 2. The image forming apparatus according to claim 1, wherein the adhesion force reducing means is a rotating brush.