JPS60263177A - Adjusting mechanism for electrostatic charging width of charger - Google Patents

Abstract

PURPOSE:To manufacture the adjusting mechanism of simple constitution at low cost by rotating a cylindrical shield body which has plural long holes corresponding to different copy magnification values and is fitted onto a charger so that the long holes face a photosensitive drum. CONSTITUTION:The shield body 17 formed of a metallic cylindrical pipe with good conductivity is arranged rotatably around the outer peripheral surface of the electrostatic charger 15. The plural long holes 18 formed in the shield body 17 correspond specific copy magnification values respectively and differ in length from one another. When reduction magnification is specified, a control circuit 36 sends out a signal corresponding to the magnification to an electromagnetic solenoid 33. A plunger 35 reciprocates repeatedly to feed a ratched wheel 19 with a claw 31a intermittently. The shield body 17 rotates and the long hole 18 corresponding to the magnification faces the outer peripheral surface of the photosensitivity drum. Only the part facing the long hole 18 of the photosensitive drum is charged electrostatically to adjust the charging width optionally.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a charge width adjustment mechanism for a charger incorporated in a copying machine.

<Prior Art and Its Disadvantages> As is well known, copying machines with a reduction function have a mechanism in which the non-image area in the direction perpendicular to the feeding direction of the transfer paper is charged during the reduction operation. Conventionally, two methods have been adopted for this purpose.Part 1
One is based on optical means using a blank lamp, and the other is one in which an R-electrode shield plate is movably arranged between the photoreceptor drum J and the charger.

In the former case, the cost increases due to the blank lamp, and in the latter case, shield plates must be prepared in accordance with the number of reduction stages, which inevitably increases the number of parts and complicates the structure.

<Objective of the Invention> The present invention has been made in order to eliminate the drawbacks of the above-mentioned conventional devices, and it is an object of the present invention to provide a charging width adjustment mechanism for a charger that has a simple structure and can be manufactured at low cost.

<Configuration and Effects of the Invention> The present invention forms a plurality of elongated holes of different lengths in a conductive cylindrical shield body which is rotatably disposed on the outer circumferential side of a charger, and a plurality of elongated holes of different lengths are formed in a conductive cylindrical shield body which is rotatably disposed on the outer circumferential side of a charger. 4+f.

The cylindrical shield body is rotated by a rotary drive means so that the elongated hole faces the photosensitive drum.

In the present invention with this configuration, the charging width can be adjusted without the need for expensive items such as blank lamps, and moreover, one cylindrical shield body can correspond to multiple copying magnifications, so the number of parts is reduced. This has the effect of simplifying the structure.

<Embodiment> An embodiment of the present invention will be described above with reference to the drawings.

FIG. 1 shows a copying machine incorporating a charging width adjustment mechanism for a charger according to the present invention. In the figure, 1 is the main body of the apparatus, 2 is a moving table, 3 is a paper feeder, and 4 is a photosensitive drum. 5 is a lamp 6, a reflector 7.
8 and a lens 9, etc., 10 is a developing tank, 1
1 is a transfer charger, 14 is a cleaning discharge light, 1
5 is a belt it'lJ-Yasha, and 16 is a transfer paper conveyance mechanism.

J On the outer peripheral surface of the charger 15, as shown in FIG. 2, a seal 17 formed of a metal cylindrical vibrator with good conductivity is arranged so as to be rotatable with respect to the charger 15. . 18 (18a to 18d) are a plurality of long holes formed equidistantly around the axis of the shield body 17 as shown in FIG. There is. 19 is a ratchet wheel fixed to one end of the shield body.

A support structure for the shield body 17 and the like is shown in FIG. In the same figure, 21.22 is the 4th photoreceptor drum (jl
A frame extending along the l1 plane, 23 is a frame 2
A high voltage lance is fixed at 1, and 23a is a socket terminal portion. The charger 15 has one end inserted into the socket terminal portion 23a, and the other end inserted into the charger holder 2.
4 is engaged with the engagement hole 25 of the frame 22, thereby being fixed to the device main body 1. 26.27
correspond to both ends of the charger 15, respectively.''-
He is a conductive collar that is fixed to each frame 21, 22 and constitutes the knoll body support means 28 together with the frame 21, 22, etc., and both ends of the shield body 17 are rotatable at this collar 26° 27. Along with being fitted externally,
The shield body 17 is electrically grounded via the collar 26.27 and the frame 21.22. 29 is a contact piece for connecting the other end of the charger 15 to the collar 27.

'' The rotation driving means 30 of the bipedal shield body 17 will be explained with reference to FIG. In the figure, 31 is a drive rod having a pawl 31a that engages with the ratchet wheel 19 in response to the spring force of a spring 32, 33 is an electromagnetic solenoid, and 34 is the electromagnetic solenoid 3.
This is a lever that transmits the reciprocating motion of the plunger 35 of No. 3 to the drive rod 31, and the drive means 30 based on these levers receives a signal corresponding to a designated copying magnification from the control circuit 36, and operates in accordance with the designated copying magnification. The shield body 17 is configured to be rotated intermittently so that the elongated hole 18 faces the photoreceptor tram 4.

Next, the operation of the above configuration will be explained.

Since the copying operation is well known, the explanation thereof will be omitted and the adjustment of the charging width will be described.

First, a desired copy magnification is specified using an operation panel (not shown) or the like. For example, when a reduction magnification of 1:0.7 is specified, the control circuit 36 sends a signal corresponding to the magnification to the electromagnetic solenoid 33. The plunger 35 of the electromagnetic solenoid 33 repeats reciprocation a number of times determined by the above signal. This reciprocating motion is transmitted to the drive rod 31 via the lever 34, and the pawl 31a intermittently feeds the ratchet wheel 19, thereby rotating the shield body 17 in the direction of arrow a in FIG.

When a long hole corresponding to the reduction magnification, for example, the long hole 18a, faces the outer peripheral surface of the photoreceptor drum 4, the plunger 3
5 stops, and the rotation of the lead body 17 also stops.

On the other hand, high voltage is applied to the charger 15 from the high voltage transformer 23, and only the portion facing the long hole 18a of the photoreceptor drum 4 is charged, and the portion not facing the long hole 18a is kept uncharged by the shield body 17. becomes. That is,
Without using an expensive blank lamp or preparing multiple shield sheets, the above charger can be installed simply by rotating the wooden shield body 17 so that the elongated hole 18 corresponding to the copying magnification faces the photosensitive drum 4. The charging width of the 15 photoreceptor drums 4 can be adjusted as desired.

Note that the shield body 17 may be formed of a metal cylindrical vibrator or may be formed of conductive resin. Furthermore, when the conductive rubber 61 is used, there is an advantage that the space in the radial direction becomes smaller (see FIG. 6).

Furthermore, if the high voltage power source is of a constant voltage drive type, the uniformity of the surface potential of the charged area of the photoreceptor drum can be made even more stable, and high-quality copied images can be stably obtained. When driving the high voltage power supply with a constant current, the high voltage output may be varied according to the set magnification.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of a copying machine incorporating the charging width adjustment mechanism of the charger according to the present invention, Fig. 2J is a perspective view showing the charger and shield body of the same device, and Fig. 3 is a cross-sectional view of the shield body, etc. 4 is a front sectional view showing the mounting structure of the shield body, etc., FIG. 5 is an explanatory diagram of the rotational drive mechanism of the shield body, and FIG. 6 is a cross sectional view showing a modified example of the shield body. be. 4-Photosensitive drum, 15-Charger 17. 61-Shield body, 18 (18a to 18d)-Elongated hole, 28-Supporting means, 301-Rotation drive mechanism applicant Sharp Co., Ltd. agent Patent attorney Hisao Komori No. 1 figure tongue figure

Claims (1)

[Claims] (11) a conductive cylindrical shield fitted over the charger facing the outer circumferential surface of the photoreceptor tram; supporting means for rotatably supporting the cylindrical shield in the axial direction with respect to the charger; The cylindrical shield body has a plurality of elongated holes formed equidistantly around the axis of the cylindrical shield body, and has a plurality of elongated holes corresponding to different copying magnifications, and a plurality of elongated holes corresponding to a specified copying magnification facing the photoreceptor drum. A charge width adjustment mechanism for a charger, comprising a rotation drive means for rotating the charger.