JPS59185361A - Method for detecting abnormality of charger in recording device - Google Patents

Abstract

PURPOSE:To detect the abnormality of a charger easily by insulating a photosensitive body electrically from other parts of a recording device. CONSTITUTION:The photoconductive photosensitive body 1 is insulated electrically from other parts of the recording device and earthed by using an exclusive earthing means 21. A current detecting means 22 is formed between the terminals of the earthing means 21 and earth current is detected at the execution of a recording process. A single reference level or plural reference levels are set up in accordance with the necessity, and when the plural levels are set up, a detected current value is compared with the respective levels successively in accordance with a fixed order. When the difference between the detected current value and the reference level exceeds an allowable value, the abnormality of the charger 2 or the like is detected.

Description

Detailed Description of the Invention (Technical Field) This invention relates to a method for detecting an abnormality in a charger in a recording device, and more specifically, in a recording device using a photoconductive photoreceptor, detecting an abnormality in a charger causing corona discharge to the photoreceptor. (Prior Art) Conventionally, Kameko copiers, optical printers, facsimile receiving devices, and the like are well known as recording devices using photoconductive photoreceptors. In such a recording device, the photoreceptor is first uniformly charged.

Then, by image exposure, an electrostatic potential field corresponding to the image to be recorded is formed. The image @exposure is on an electronic copying machine (
Well, this is done by irradiating a light image of the original to be copied, and in optical printers and facsimile receiving devices, one line of optical signals whose intensity is modulated by one image signal is one intensity modulated. It is done by irradiation with a beam etc.

The electrostatic latent image formed on the photoconductor is transferred to a recording medium such as paper, and then developed and visualized. A visible image is obtained when the image is transferred onto a recording medium such as paper.

In such a recording device using a photoconductive photoreceptor, one or more chargers are inevitably used due to the recording process.
The corona discharge from the charger to the photoreceptor is closely related to the recording process. Therefore, if any abnormality occurs in the charger, the recording process will be stopped immediately. Trouble? cause.

Therefore, there is a need to detect abnormalities in the charger, but conventional methods for detecting this abnormality have been
It directly produced the charging current of each charger, and detected abnormalities in the charger itself based on abnormalities in the charging current.

This method is accurate and reliable, but when there are multiple chargers to detect an abnormality, it is necessary to install an abnormality detection means for each charger.
Problems were the complexity, size, and cost of the equipment.

(Objective) Therefore, an object of the present invention is to solve the above-mentioned problems and provide a method for detecting an abnormality in a two-digit charger in a recording device, which can easily detect abnormalities in the charger.

(composition) The present invention will be explained below.

The charger abnormality detection method according to the present invention is characterized by the following points.

First, the photoconductive photoreceptor is electrically isolated from the rest of the recording device and is grounded using dedicated grounding means.

A current sensing means is provided between the terminals of this dedicated grounding means, so that the earth current is detected during execution of the recording process. The current value determined by the current detection means is:

Comparison with a preset reference level 2'1. reactor. Standard 1
Novel: Singular or plural as necessary, plural -
, 3- When 1 novel is set, the comparison between the Kichiton flow value and each 1 novel is performed in a certain order! a')
n, ro.

Is the difference between the Tochiton flow value and the standard +7 bells an acceptable value? Once it crosses the line, the problem with the charger becomes apparent.

Application of the present invention is particularly suitable when the photoconductive photoreceptor is a belt-shaped photoreceptor, as described below.

A specific example will be explained below with reference to one drawing.

Is Fig. 1 an example of a recording device to which the present invention is applied? Only important parts are schematically shown for explanatory purposes. That is, in Fig. 1, reference numeral 1 indicates a photoconductive photoconductor, 2 indicates a charger, 3 indicates an image exposure position, 4 indicates a display device, 5 indicates a charger for visible light transfer, and 6 indicates a separation. charger for
Code 7 is a charger for cleaning pretreatment, code 8
(The cleaning device, numeral 9 is a charger for static elimination, numerals 10 to 13 are pulleys, and numeral S is transfer paper for storing the medium?).

First, I will briefly explain the recording process.

The photoreceptor 1 is formed in the shape of an endless belt.
-! It is hung from J-10 to Engineering 3, counterclockwise) 5
Rotate in the direction.

At the start of the process, the photoreceptor 1 starts rotating, then the charger 7 starts discharging, and following this, the cleaning device 8 is activated.

Therefore, the circumferential surface t'11 of the photoreceptor 10. First, a pre-cleaning treatment is performed by corona discharge from the charger 7, and then cleaning is performed by the cleaning device 8. When the circumferential surface of the photoreceptor that has been thoroughly cleaned comes to the position of the charger 9, the charger 91 discharges corona to the photoreceptor 1 to eliminate static from the photoreceptor 1.

When the photoreceptor part that has been neutralized reaches the position of the charger 2, the charger 2 applies a corona discharge to the photoreceptor to uniformly charge the circumferential surface of the photoreceptor, and the photoreceptor part that has been uniformly charged in this way is charged. When reaching the image exposure section 3, one image (image exposure is performed and an electrostatic latent image is formed.Image 1W exposure "i 't': f, .
This is carried out by irradiation of a single image of light, or by irradiation of a light signal that has been modulated in intensity.

Thus, the shape 1iWsa71. The 1st submerged object is visually controlled by the 1st observation device 4. As the photoreceptor 10 rotates, the image formed on the photoreceptor I by development approaches the transfer section 1, that is, the area between the photoreceptor 1 and the charger 5. In synchronization with the movement of this visible image, the transfer paper S is fed into the transfer section.

It's superimposed with the visible 1 house.

At this time, the charger 5 emits a corona discharge, and due to this action, the visible image is transferred onto the transfer paper S.

Due to the action of corona discharge from the charger 6, the transfer paper S, together with the visible image, is separated from the photoreceptor 1.
After being subjected to necessary treatments such as soaking, the image is discharged from the recording apparatus as a recorded image f'1. Ru.

- 10,000, '5T inkstone transfer photoreceptor 1k; While rotating, it receives corona discharge from the charger 7 and cleaning from the cleaning device 8.

Now, the photoreceptor 1 is a belt-shaped photoreceptor, and as shown in FIG. 2, it has a dielectric support film IOO.

For example, a conductive layer 101 is formed by vapor-depositing aluminum on an Eva Mylar film or the like, and a photoconductive layer 102 is further formed on this conductive layer. The photoconductive layer 102 is, for example, an OPC layer.

Due to this configuration of the belt-like photoreceptor, the photoreceptor 1
)'1, by simply winding f'l- around the pulleys 10 to J3, the photoreceptor 1 can be electrically insulated from other parts of the recording apparatus.

When carrying out the present invention, two knives are used.

It is a requirement that the photoreceptor be electrically insulated from other parts of the recording device, but in the case of a belt-shaped photoreceptor, this requirement is not met due to its structure, as mentioned above. will naturally be satisfied.

In contrast, a well-known drum-shaped photoreceptor is used to form a line and a photoconductive layer σ-
) Since the support itself is conductive, it is necessary to insulate the photoreceptor by using a special insulating means for the holder that holds the photoreceptor itself in the apparatus.

Now, in FIG. 2, the horizontal direction is the width direction of the photoreceptor 10, that is, the direction perpendicular to the drawing in FIG. 101
Conductive part 1 by applying carbon paint directly on it.
03, the photoreceptor 1 is grounded using a dedicated grounding means 21.

The terminal of the grounding means 2J, which corresponds to the photoconductor 1, is a conductive brush 20, and is in sliding contact with the conductive portion IO3 of the photoconductor 1.

A current detection device 22 is provided between the terminals of the grounding means 2J, which detects the ground current to the photoreceptor 1 and outputs a detected current value (1). Using this detected current value 10, an abnormality in the charger 2 or the like is detected.

Now, chargers 2.5, 6.7, and 91'i all perform corona discharge on photoreceptor 1, but chargers 6 and 9 use AC corona discharge, and charger 2.5.7 uses DC corona discharge.

Therefore, for the sake of simplicity, the following explanation will be based on the assumption that an abnormality in charger 2.5.7, which performs direct current corona discharge, is detected.

- Stiff] Charger 2 discharge polarity for the 1st 8
- is of negative polarity. Then, charger 5.7
The discharge polarity of is correspondingly determined as positive polarity and negative polarity.

Also, looking at the discharge currents of chargers 2 and 5, although they both have negative polarity, the discharge current of charger 2 is thicker.

Therefore, a DC ammeter is used as the current detection device 22 in FIG. 2. The influence of the charger 6.9 which performs AC corona discharge cannot be detected by the DC ammeter. Therefore, depending on the output of the DC ammeter, the charger 2.5
．． You can know the influence of 7.

Therefore, assuming a case where a single copying process is performed,
At this time, the recording device shown in FIG. 1 is operated.

Assuming that each charger 2, 5, 6, 7, and 9 is functioning normally, the current value detected by the DC ammeter as the current detection device changes as shown in FIG. Current levels A and B in FIG.

(This is the level of the ground current corresponding to the corona discharge of charger 7.5.2. If each charger is functioning normally, then this , c are constant. Therefore, this n
It is set as one novel based on level A, B, and CY standards.

In FIG. 3, the time domain (2) indicates the time at which the process starts and the charger 2 discharges. The charger 7 applies a positive corona discharge to the photoreceptor 1 while the process is progressing. Time domain lTl1, discharge time by charger 2, time domain I
TH, Charger 2 has stopped discharging Charger 2 has charged the battery. Time required for the photoreceptor portion to reach the transfer section (1 hour) Region M is the discharge time of the charger 5 for transfer, and time region V is the time from the transfer until the end of the process. I'll show you my anus.

Now, the standard 1 novels A, 13, and C were set as described above.

Therefore, in the actual recording process, the detected current value ■ is the output of the DC ammeter as the current detection means. is applied to the comparator circuit, and the reference level A is also applied to the comparator circuit.
, B, and C. Of course, the reference level is applied to the comparator circuit by applying the ties shown in Figure 3 (NG, ■, m, tv, vi
According to - (, A, C.

Switch in the order of A, B, A.

And the detected current value ■. and Standard 1 novels A and B.

Detect the difference from C. If each charger 2.5.7 functions normally, the above difference should be close to O. Therefore,
An abnormality is assumed to have occurred when the difference between the detected current value ■ and the reference level exceeds a certain preset tolerance value. When this abnormality occurs, compare it with the detected current value ■0. Whether the reference 1 novel being read is A, B, or C can be known from the timing. If the reference level that has been carefully compared at the time of occurrence of an abnormality is, for example, B, it can be seen that an abnormality has occurred in the charger 5. In this way, you can detect the occurrence of an abnormality and at the same time identify the charger where the abnormality is occurring.

The above is a case where a single recording process is performed.
It was. When several recording processes are carried out in succession, each charger's discharge period is controlled at a fixed interval of 11-4 minutes, after which time the necessary consecutive processes are terminated. , Continue the continuous discharge with the valley charger. Therefore, the timing of switching the reference level is as shown in FIG. 4, and one new novel D is added. Standard 1 Novel D is Charger 2
．． This is the normal value of the earth current corresponding to the combination of the discharge current according to 5.7.

In this case, each of the 17 bells is compared with the detected current value τ0, and when the difference between the two exceeds a certain tolerance value.

Based on that fact, you can detect the existence of an abnormality.

Note that instead of changing the reference levels A, I3, etc. over time and inputting them to the comparison circuit, the reference l/bells A, B, etc. are fixed and the detected current value o is compared with them. Current value ■ What level should be compared with o? It may be set to 5 to switch depending on the timing.

FIG. 85 shows an example of a control system when the present invention is applied to the apparatus shown in FIG.

The current detection device 22 detects the charge flowing into and out of the photoreceptor due to the corona discharge gradient of the chargers 2.5, 6, and 7.9 as a modulation of the ground current. The current detection device 22, in this example, includes a direct current detection device and an alternating current detection device so that the influence of alternating current corona discharge can also be detected.

The current value detected by the current detection device 22 is applied to the comparison circuit f'L. The reference 1 novel is stored in the control device, and a predetermined level is converted into a signal by the reference signal circuit and applied to the comparison circuit according to a predetermined timing controlled by the control device.

Comparison circuit (compares the detected current value and base level, and applies the difference to the control device.The control device determines whether or not there is an abnormality based on the applied signal. If it is an adjustable abnormality, the charger 2.5+6,7t9 discharge 1-channel C2, C5, C
6, C7, and C9 that correspond to the charger in which the abnormality has occurred, and remove the abnormality. Also, if the abnormality cannot be adjusted and is resolved, the abnormality is displayed and recorded. Take necessary measures such as stopping the operation of the device. In addition to corona discharge from the charger and ground current, charge transfer to and from the photoconductor is caused by charge transfer due to friction with the far run of the cleaning device, and dust particles. There are changes in the toner charge amount due to charge movement through the toner and toner adhesion during the phenomenon. As a result of their experiments, Koori et al.
We investigated the input and output of electric charge through the turtle and confirmed that it is a slight error that can be treated as an error. It goes without saying that the present invention can be carried out using the following methods.

(Effects) According to the present invention, it is possible to provide a novel method for detecting an abnormality in charring. In this method, there is no need to provide an abnormality detection means for each charger, so the device does not become large or complicated, and can be implemented with a simple device at low cost.

[Brief explanation of drawings]

FIG. 1 is a front view schematically showing only the main parts of an example of a recording device to which the present invention can be applied, and FIGS.
5 is a diagram for explaining the present invention, and FIG. 5 is a block diagram showing an example of a control system when the present invention is implemented in the recording apparatus shown in FIG. 1. 1... Belt-shaped photoreceptor, 2, 5, 6, 7.9.
...Charger, 21...Grounding means, 20.
...to conductive plan as a terminal for grounding means - 499

Claims (1)

[Claims] 1. In a recording device using a photoconductive photoreceptor. A method for detecting an abnormality in a charger that discharges corona by illuminating the photoreceptor. The photoconductive photoreceptor is electrically insulated from other parts of the recording device, and the photoreceptor is grounded using a dedicated grounding means, and a current detection means is connected between the terminals of the grounding means. The current value detected by the current detecting means is compared with a preset reference level, and when the difference between the two exceeds an allowable value, an abnormality in the charger is recognized. A method for detecting an abnormality in a charger in a recording device. 2. A method for detecting an abnormality in a charger in a recording device according to claim 1, wherein the photoconductive photoreceptor is a belt-shaped photoreceptor;