JPH0426868A - Device for measuring irregularity of discharge for corona discharger - Google Patents

Abstract

PURPOSE:To detect the irregularity of discharge of a corona discharger with high accuracy and with high efficiency by moving a wire sensor which has a conductive wire orthogonally crossed with the discharge wire of the corona discharger along the discharge wire when the corona discharger discharges and measuring a current along all the area of the discharge wire. CONSTITUTION:The wire sensor 29 is provided, which has the conductive wire opposingly laid so as to be orthogonally crossed with the discharge wire 91C held by the holding part of the corona discharger 91. Then, the wire sensor 29 is moved along the discharge wire 91C to measure the value of the current which flows in the sensor 29 by the discharge of the wire 91C. Thus, the irregularity of discharge of the corona discharger is correctly and accurately measured along the entire discharge wire 91C.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a discharge unevenness measuring device for a corona discharger used in an image forming apparatus such as a copying machine or a printer.

(Prior Art) Many corona dischargers are used in image forming apparatuses such as electrophotographic copying machines and printers. For example, an electrophotographic copying machine uses a main charging corona discharger for charging a photoreceptor drum, a transfer corona discharger for transferring a toner image on the photoreceptor drum onto transfer paper, and the like. In a corona discharger, a discharge wire is usually installed within a shield case, and corona discharge is performed through an opening of the shield case that is open opposite to the discharge wire.

When such a corona discharger is installed in an image forming apparatus, it is necessary to check that it has desired discharge characteristics. In particular, the corona discharger used as the main charging device cannot uniformly charge the surface of the photoreceptor drum unless corona discharge is uniformly discharged from the entire discharge wire. However, if the discharge wire is twisted or has dust or the like attached to a part of the discharge wire, the corona discharge will not be uniformly discharged from the entire discharge wire. Therefore, when manufacturing an image forming apparatus such as an electrophotographic copying machine, the discharge state of the corona discharger used as the main charging device is inspected.

Conventionally, the discharge characteristics of the corona discharger, which is the main charging device, have been determined by attaching the corona discharger to the main body of the image forming apparatus, forming an image, and inspecting the discharge state of the discharge wire based on the state of the image. ing. In such a method, a corona discharger must be attached to the main body of the image forming apparatus to form an image, which poses a problem of poor work efficiency. Furthermore, since consumables such as developer and transfer paper are consumed during image formation, economic efficiency is impaired. If an abnormality is detected in the corona discharger, it is necessary to remove the corona discharger attached to the main body of the image forming apparatus, resulting in a decrease in work efficiency.

In order to solve this problem, the applicant of the present application proposed in Japanese Patent Application No. 199670/1983 that a minute slit B disposed opposite to the charge wire is moved along the charge wire in the discharged state. developed a method and device for measuring discharge unevenness in a corona discharger by measuring the leakage current from the microslit using a potential sensor.

(Problems to be Solved by the Invention) With such a discharge unevenness measuring device, discharge unevenness of a corona discharger can be detected without image formation, and workability is significantly improved. However, since the leakage current passing through the minute slits is detected, if the width of the minute slits is wide, there is a possibility that changes in the leakage current cannot be detected accurately.

The present invention solves the above-mentioned conventional problems, and its purpose is to provide a discharge unevenness measuring device for a corona discharger that can accurately and precisely measure the discharge unevenness of a corona discharger along the entire discharge wire. It is about providing.

(Means for Solving the Problem) The discharge unevenness measuring device for a corona discharger of the present invention has a holding part that can hold a corona discharger in a predetermined state and apply a predetermined voltage to the held corona discharger. and a wire sensor having a conductive wire installed so as to be orthogonal to the discharge wire of the corona discharger held by the holding part, and moving the wire sensor along the discharge wire. and means for measuring a current value flowing into the wire sensor due to corona discharge by a corona discharger, thereby achieving the above object.

(Function) In the corona discharger discharge unevenness measuring device of the present invention, a wire sensor of a conductive wire that is perpendicular to the discharge wire of the corona discharger is moved along the discharge wire. A current value flowing into the wire sensor due to discharge of the discharge wire is measured. Then, based on the measured value, discharge unevenness of the discharge wire is determined.

(Example) The present invention will be described below with reference to Examples.

As shown in FIGS. 1 and 2, the apparatus for measuring discharge unevenness of a corona discharger according to the present invention includes a rectangular parallelepiped-shaped shield box 10 and a measuring section 20 provided inside the shield box 10. The shield box 10 has a box main body part 11 with an open front surface, and a drawer part 12 that is movable in the front and rear directions from the open front surface of the box main body part 11. The measurement section 20 is attached to the drawer section 12.

The measurement unit 20 measures, for example, discharge unevenness of a corona discharger 91 used as a charging device of a laser printer. This corona discharger 91 includes a shield case 91a formed as a part of a cover unit 9o that covers a photoreceptor drum of a laser printer.
A corona wire 91c is inserted inside a. Furthermore, the opening of the shield case 91a is covered with a grid 91b.

The drawer part 12 in the shield box lO is moved in the horizontal direction with respect to the box main body part 11 so that it is in a storage position located in the box main body part II and a drawer position in which it is pulled out from the box main body part 11. Ru. When the drawer section 12 is housed in the box main body 11, the inside of the box main body 11 is electromagnetically shielded. On the front side inside the drawer section 12, there is a measuring section 2.
The substrate 21 of No. 0 is attached at an angle of about 45 degrees.

As shown in FIG. 3, the substrate 21 is provided with a pair of support columns 22 at an appropriate interval in the width direction perpendicular to the moving direction of the drawer section 12. Each support column 22 protrudes toward the inside of the drawer section 12 in a state substantially perpendicular to the substrate 21 .

Support pins 23 and 23 protruding in directions away from each other are provided at the tip of each support column 22 in a substantially horizontal state. Each support pin 23 supports the cover unit 90. In this way, the cover unit 90 and the support bin 23
When the state is maintained, the corona discharger 91 of the cover unit 90 is electrically connected to a predetermined terminal of the cover unit 90, and a predetermined voltage can be applied.

A guide rail 24 extending in the width direction is provided on the board 21. The guide rail 24 has a length corresponding to the length of the corona wire 91c of the corona discharger 91 whose discharge unevenness is to be measured. On one side of the guide rail 24, as shown in FIG.
The sides of the two are slidably engaged. The sensor support 25 is attached to a toothed belt 27. The toothed belt 27 is wound around a pair of toothed pulleys 26a and 26b disposed corresponding to each end of the guide rail 24, respectively. One toothed pulley 26a
is connected to the output shaft of a stepping motor 28, and when the stepping motor 28 is driven, the sensor support base 25 is moved along the guide rail 24.

The upper surface of the sensor support base 25 has a horizontal portion on the guide rail 24 side, and, except for the horizontal portion, is an inclined surface that is gradually lowered from the horizontal portion. When the drawer section 12 is accommodated in the shield main body section 11 with the cover unit 90 attached to the unit holding section 30, the inclined surface comes to face the grid 91b of the corona discharger 91 in a parallel state. ing. A wire sensor 29 made of conductive wire is installed on the sensor support base 25 in the same inclined state as this inclined surface and at a predetermined distance from the inclined surface. A current flows into the wire sensor 29 when corona discharge is performed by the discharge wire 91c of the corona discharger 90.

As shown in FIG. 1, a control section 40 using, for example, a microcomputer is disposed within the box main body 11 of the shield box 10. As shown in FIG. The control section 4
0 applies a predetermined voltage to the corona discharger 91 of the cover unit 90 attached to the unit holding part 30 in the drawer part 12, and drives the stepping motor 28 of the measuring part 20. Further, the value of the current flowing into the wire sensor 29 is input to the control unit 40 . The control section 40
The output is displayed on a display section 41 using a CRT provided above the part of the box main body section 11 where the drawer section 12 is accommodated.
is also given.

The box main body 11 of the shield box 10 is provided with an exhaust fan (not shown), and the gas inside the shield box 10 is exhausted by the fan through an ozone filter.

The operation of the apparatus for measuring discharge unevenness of a corona discharger having such a configuration is as follows. Turn on the main switch of the measuring device, and open the box body 11 of the Seal Topo 7x 10.
The drawer section 12 is compared from .

In this state, the cover plate 90 provided with the corona discharger 91 is supported by the support pin 23.

When the cover unit 90 is attached to the support pin 23, the corona discharger 91 of the cover unit 9o is electrically connected to a predetermined terminal. Then, the drawer part 12 is pushed into the box main body part 11 so that the drawer part 12 becomes a part housed in the box main body part 11. In this situation, cover unit 9
The grid 91b of the corona discharger 91 of No. 0 is in a state facing the wire sensor 29.

When the drawer section 12 is housed in the shield main body section 11, the control section 40 starts measurement control of discharge unevenness of the corona discharger 91. The control unit 40 first applies a predetermined voltage to the corona discharger 91. As a result, the corona discharger 91 starts discharging. On the other hand, the control unit 40 drives the stepping motor 28 to move the sensor support base 25
is moved to the measurement start position at one end of the guide rail 24. When the sensor support base 25 is moved to the measurement start position, the control unit 40 reads the current value flowing into the wire sensor 29 and rotates the output shaft of the stepping motor 28 at a predetermined rotation angle (for example, 0.36 degrees). ), and the sensor support stand 25 is moved stepwise along the guide rail 24 by a predetermined distance (for example, 0.055+m). The control unit 40 controls the sensor support base 25
is moved a predetermined distance, the wire sensor 29
Read the current value flowing into. In this way, by moving the sensor support stand 25 from one end to the other end along the guide rail 24, the wire sensor 29 is moved along the entire area of the discharge wire 91c in the corona discharger 91. The discharge state of the discharge wire 91c is measured over the entire area based on the current value flowing into the wire sensor 29.

In this way, when the discharge state of the discharge wire 91c in the corona discharger 91 is measured over the entire area, the control unit 40 makes the current value flowing into the wire sensor 29 correspond to the distance from the measurement start position. It is graphed and displayed on the display unit 41. And wire sensor 29
If the value of the current flowing into the corona discharger 90 is within a predetermined range, it is displayed on the display unit 41 that the discharge state of the corona discharger 90 is normal. If even a portion of the current flowing into the wire sensor 29 is outside the predetermined range, an indication of ineligibility is displayed on the display section 41.

During such measurements, a fan provided within the shield main body 11 is driven, and ozone generated during corona discharge by the corona discharger 91 is discharged to the outside of the shield box 10 via the ozone filter.

When the measurement of discharge unevenness of the corona discharger 91 is completed in this way, the drawer part 12 is pulled out from the shield main body part 11 and the cover unit 90 provided with the corona discharger 91 is removed from the unit holding part 30. . Then, the main switch is turned off and the measurement operation ends.

(Effects of the Invention) As described above, the corona discharger discharge unevenness measuring device of the present invention uses a wire sensor constituted by a conductive wire that is orthogonal to the discharge wire of the corona discharger. During discharge, the current value flowing into the wire sensor is measured along the entire discharge wire by moving it along the discharge wire, so that the discharge unevenness of the corona discharger is prevented with high accuracy and high efficiency. can be done. Since the discharge state along the entire area of the discharge wire can be captured, twisting of the discharge wire and local dirt on the discharge wire can also be detected.

4. Figure 1 is a schematic configuration diagram of the discharge unevenness measuring device for a corona discharger according to the present invention, Figure 2 is a side view of the main part thereof, and Figure 3 is a plan view of the measuring section of the device. , FIG. 4 is a perspective view of the main part of the measuring section.

DESCRIPTION OF SYMBOLS 10... Turned Bonox, 11... Turned main body part, 12... Drawer part, 20... Measurement part, 21
. . . Substrate, 22 . . . Support portion, 24 . . . Guide rail, 25 .・Cover unit, 91...Corona discharger, 91a...Nold case, 91b...Guri,
91c...discharge wire or higher

Claims (1)

[Claims] 1. A holding part capable of holding a corona discharger in a predetermined state and applying a predetermined voltage to the held corona discharger, and a discharge of the corona discharger held by the holding part. a wire sensor having a conductive wire installed so as to be perpendicular to the wire; means for moving the wire sensor along the discharge wire; and a means for moving the wire sensor along the discharge wire; A discharge unevenness measuring device for a corona discharger, comprising means for measuring a current value flowing into the corona discharger.