JPS6162076A - Scorotron electrifier for copying machine - Google Patents

Abstract

PURPOSE:To prevent a glid wire from toner pollution effectively and to keep high copying quality by forming a clean air feeder for supplying clean air into a shielding member. CONSTITUTION:When a scorotron electrifier is driven, ion air B is generated and air containing toner or the like tries to flow into the shielding member 4. Since cleaned air is always supplied into the shielding member 4 from a filter 9 in the clean air feeder 5, the shielding member can be effectively prevented from the inflow of air containing toner or the like. Even if the scorotron electrifier is driven over a long period, a glid wire 3 prevented from the adhesion of toner or the like is effectively worked and a low potential part is raised, so that the distribution of an electric field is uniformed and a prescribed uniform electrostatic charge potential can be obtained on the surface of a photosensitive body 1.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a charging device for a copying machine, and particularly relates to a corona wire that applies a predetermined potential to a photoreceptor by corona discharge, and a discharge of the corona wire. The present invention relates to a scorotron charging device equipped with a grid wire that can adjust unevenness and apply a uniform potential to a photoreceptor.

[Conventional technology]

Conventionally, as shown in FIG. 5, a charging device for a copying machine has a structure in which a corona wire (b) is attached to a shield member (a) that is open toward the photoreceptor (circuit). A predetermined potential is applied to the photoreceptor by corona discharge from the corona wire (b), and charging is performed, but toner enters from the opening (e) of the shield member (a) and the corona wire ( (b) may cause unevenness in corona discharge, resulting in non-uniform charging of the photoreceptor.

Therefore, a scorotron charging device has been proposed that can apply a uniform potential to the photoreceptor even if toner adheres to the corotron wire (b).

As shown in FIG. 6, this scorotron charging device has a grid wire (f) consisting of a plurality of thin wires attached to the opening (el side) of a shield member (d). , even if unevenness occurs in the corona discharge caused by the corona wire (gl), an uneven electric field formed between the corona wire (g) and the photoreceptor (circuit) due to the unevenness of discharge is applied to the grid wire (f). The voltage is corrected using a predetermined potential, and the charging on the photoreceptor is made uniform.

[Problem that the invention seeks to solve]

By the way, in this scorotron charging device, as shown in FIG.
As a result, an air flow (hereinafter referred to as HL) is generated from the inside of the shield member (DL) to the outside, and the thinned shield member (hereinafter referred to as HL) is generated. However, this air flow (il) may contain floating toner etc. scattered from the cleaning device, developing device, etc., and if it is used as it is for a long period of time, In particular, if toner etc. is concentrated on the end of the grid wire (f+) and left as is, this grid wire (d)
may no longer be able to perform its intended function.

That is, it becomes difficult to adjust the uneven electric field distribution due to discharge unevenness of the corona wire (GL) using the grid wire (DL), and as a result, the distribution of the charged potential on the photoreceptor becomes uneven, causing fogging. etc., resulting in deterioration of copy image quality.

[Means and effects for solving the problems] That is, the present invention provides a corona wire that is provided near a photoreceptor and applies a predetermined potential on the photoreceptor by corona discharge, and a connection between the corona wire and the photoreceptor. In a scorotron charging device for a copying machine, the scorotron charging device for a copying machine is equipped with a grid wire for adjusting discharge unevenness, and a shield member for attaching these corona wires and grid wires. The clean air supplied from the clean air supply device prevents toner, etc. from adhering to the grid wire, and prevents the corona wire and exposure to light due to uneven discharge. Even if a non-uniform electric field is generated between the photoreceptor and the photoreceptor, the above-mentioned grid wire, to which toner does not adhere, reliably compensates for this non-uniform electric field. This results in a uniformly charged state.

〔Example〕

The present invention will be described below based on embodiments shown in the accompanying drawings.

FIG. 1 shows a scorotron charging device for a copying machine to which the present invention is applied.
A corona wire (2) provided near the photoreceptor (1), a grid wire (3) provided between this corona wire (2) and the photoreceptor (1), and these corona wires (
2) and a shield member (4) to which the grid wire (3) is attached, and a clean air supply device (5) provided on this shield member (4) and supplying clean air (N) into the inside of this shield member (4). It is composed of.

The corona wire (2) generates a corona discharge on the photoconductor (1) which has been neutralized to zero potential by a static eliminator (not shown), and uniformly applies a predetermined potential onto the photoconductor (1) by this corona discharge. In this embodiment, a high voltage of -5 kVO is applied to a thin metal wire installed parallel to the rotation axis C circuit of the photoreceptor (1).

The grid wire (3) is the corona wire (2)
This is intended to equalize the electric field ζ formed between the corona wire (2) and the photoreceptor (1), but if a low potential portion occurs in the electric field due to uneven discharge, etc. This grid wire (3) adjusts the low potential part, and in this embodiment, it is composed of a plurality of thin metal wires to which a voltage of -1000V is applied, and is parallel to the corona wire (2). and is installed between the corona wire (2) and the photoreceptor (1).

The shield member (4) prevents ions, etc. generated from the corona wire (2) from diffusing into unnecessary areas when the corona wire (2) performs corona discharge, and also prevents the corona wire (2) It provides complete protection and is box-shaped with an approximately U-shaped cross section and has an opening (4a) that opens toward the photoreceptor (1).

Further, the shield member (4) is provided with a supporting portion (6) on the longitudinal end side of the shield member (4) along the rotation axis of the photoreceptor (1), and the corona wire (2) )
and a grid wire (31) are fixedly attached thereto.The shield member (4) is made of a conductive material such as AA, is grounded, and constitutes a ground electrode.

The clean air supply device (5) constantly supplies clean air (A) toward the inside of the shield member (4) from the back or side surface of the longitudinal end of the shield member (4). In this example, the shield member (4)
An air intake pipe (8) whose distal end side is attached to an opening hole (7) opened on the back side of the longitudinal end side of the 8)
It consists of a filter (9) that purifies the air that enters the area. This clean air supply device (5) supplies clean air (A) toward this low pressure part because the air inside the shield member (4) becomes diluted when ion wind (B) is generated from the corona wire (2). is starting to enter.

As described above, the clean air purifying device (5) of this embodiment has a configuration in which the filter (9) is attached to the base end side of the pipe, and the air is purified here and supplied to the inside of the shield member (4). However, the present invention is of course not limited to this. For example, as shown in FIG. To prevent this, a fan (13) is provided, and this fan (
13) may be used to forcibly send air into the shield member (4), or as shown in Figure 4, a similar effect can be achieved by attaching a filter (one stage) directly to the opening hole circle without using a pipe. Anything other than this is also possible as long as it plays.

Therefore, according to this embodiment, even if the scorotron charging device operates and generates ion wind (Bl), and therefore air containing toner etc. tries to flow into the shield member (4), clean air is not supplied. Since purified air from the filter (9) of the device (5) always flows into the shield member (4), the inflow of air containing toner and the like is effectively prevented.

Therefore, even if the scorotron charging device operates for a long period of time, the grid wire (3) will not be contaminated with toner etc. due to the influx of air containing toner etc., which is the case in the past. Even if discharge unevenness occurs in 2) and the electric effect distribution between the photoreceptor (1) and the corona wire (2) becomes uneven, the grid wire (3), which does not have toner attached, will work effectively. As a result, the low potential portion is increased and the electric field distribution becomes uniform, thereby obtaining a predetermined uniform charging potential on the photoreceptor (1).

〔Effect of the invention〕

The scorotron charging device for a copying machine according to the present invention has the above-described configuration, and the clean air constantly supplied to the inside of the shield member by the clean air supply device constantly prevents air containing toner from flowing into the inside of the shield member. Since it is possible to effectively prevent toner contamination of the grid wire, there is no deterioration in copy image quality such as uneven copy density or fog, and high quality copy images can be maintained over a long period of time. , the effect is great.

[Brief explanation of the drawing]

1 and 2 are a schematic side sectional view and a sectional view taken along the I-■ arrow, showing a scorotron charging device for a copying machine according to the present invention;
8 and 4 are schematic side cross-sectional views showing other embodiments of the scorotron charging device for a copying machine according to the present invention, and FIGS. 5 and 6 are schematic perspective views showing a conventional charging device. can be,
A corotron charging device and a scorotron charging device are shown, respectively. [Code explanation]

Claims (1)

[Claims] A corona wire that is provided near the photoreceptor and applies a predetermined potential to the photoreceptor through corona discharge, a grid wire that is provided between the corona wire and the photoreceptor to adjust discharge unevenness, and these corona wires and A scorotron charging device for a copying machine comprising a shield member to which a grid wire is attached, wherein the shield member is provided with a clean air supply device for supplying clean air into the inside of the shield member. Charging device.