JPS61121065A - Method for discriminating abnormal state of copying machine - Google Patents

Abstract

PURPOSE:To discriminate surely the abnormal state by attaching a surface potential sensor and a toner concentration sensor near a photosensitive body and discriminating whether a copying function executing part or a sensor part is abnormal or not on the basis of detection signals of both sensors. CONSTITUTION:A surface potential sensor 13 and a toner concentration sensor 19 are attached near a photosensitive drum 1. If the detection signal of the surface potential sensor 13 is within the range of the an area R1, it is judged that the surface potential of the photosensitive drum 1 is a correct value; and if the detection signal of the toner concentration sensor 19 is within the range of an area R2, it is judged that the quantity of the toner attracted to the surface of the photosensitive drum 1 is a correct value. Said discrimination processings are performed in every one copying operation, and it is judged that a high voltage unit 21, a charging charger 12, or the like is abnormal if detection signals of both sensors are on the outside of correct ranges, and it is judged that the sensor which outputs the detection signal on the outside of the correct range, a control part, or the like is abnormal if only this detection signal is on the outside of the correct range.

Description

[Detailed description of the invention] Technical fields> The present invention relates to a method for determining an abnormal state of a copying machine.

<Prior Art> 7. Conventionally, by installing a surface potential sensor or a toner concentration sensor, it is possible to control the operation of a copying function performing section of a copying machine, such as a high voltage unit that applies high voltage to an electrostatic charger, a portion around the electrostatic charger, etc. A state-sensing copier is provided.

In such a copying machine, if the above-mentioned sensor is operating normally, it is possible to accurately detect whether the above-mentioned operating state is appropriate or not, and to promptly take measures against the incorrect operating state. , a proper copy can be obtained. Further, if the detection signal of the sensor is outside the permissible range, it is determined that the copying function execution section is in an abnormal state, and the abnormal state can be dealt with.

However, it is not necessary to determine whether or not the above-mentioned sensor is operating normally, and the copying function execution unit must be controlled solely based on the sensor's detection signal. Even if there is only one shift, a detection signal indicating that the surface potential is abnormal may be output due to a failure of the sensor unit (sensor, sensor control unit). In this case,
As the voltage applied to the charger continues to increase or decrease, the surface potential of the photoreceptor becomes far from the proper value, producing copies of inferior quality, and in the worst case. has the problem of producing copies whose basolateral characteristics cannot be determined.

In addition, in order to solve the above problems, it is necessary to install a special determination means to determine whether or not the sensor is operating normally, which not only complicates the configuration but also increases costs. This will give rise to a new problem.

Purpose> This invention was made in view of the above problems,
An object of the present invention is to provide a method for determining an abnormal state of a copying machine, which can reliably determine an abnormal state without installing a special determining means for determining the operating state of a sensor mounted close to a photoreceptor. There is.

In order to achieve the above object, the abnormal state determination method of the present invention determines whether there is an abnormality in the copying function execution unit based on detection signals from a surface potential sensor and a toner density sensor that are installed close to the photoreceptor. , which determines whether the sensor unit is abnormal, and when the detection signals of both sensors are abnormal state detection signals,
If it is determined that there is an abnormality in the copying function execution unit and only the detection signal of one sensor is an abnormal state detection signal, the sensor that outputs the abnormal state detection signal or the sensor control unit is abnormal. It can be determined that

<Example> Hereinafter, embodiments will be described in detail with reference to the accompanying drawings showing examples.

FIG. 1 is a schematic diagram showing the main parts of a copying machine, in which a pre-exposure lamp (
11), electrification charger (12), surface potential hinger (1
3), blank lamp (14), developing device I (15),
Pre-transfer static elimination lamp (16), transfer charger (17),
Separation charger (18), toner concentration sensor (19),
Then, install the crease (20) in this order. Note that (21) is a high voltage unit for applying a DC high voltage to the charger (12).

Further, (3) is an optical system for exposing the original on the original placing table (31) to form an original image on the photosensitive drum (1), which includes a light source (32), a reflecting mirror (33 )(34H3
5), a lens (36), and a reflector 1 (37), and can form an original image on the exposure area E of the photoreceptor drum (1). In addition, (38) is a black mock manuscript,
The light source (32
) is installed at a predetermined distance away from the home position side.

In addition, (4) is the copy paper tray feeding section, and the paper feed cassette (
41) The paper feed roller (
42), a paper feed path (43), a registration roller (44) that conveys the copy paper (P) in synchronization with the photosensitive drum (1),
A conveyor belt (45) that conveys the copy paper (P) separated from the photoreceptor drum (1) by the separation charger (18).
, a fixing roller (46), and a receiver m (47).

With the above configuration, each time a copying operation is performed, an electrostatic charge corresponding to the simulated original (38) is first applied to the exposure area E of the photosensitive drum (1), which is uniformly charged by the charging charger (12). A latent image is formed, and the surface potential is detected by a surface potential sensor (13), and developed into a toner image by a developing device (15).
The toner concentration is detected by the cleaner (20).
The toner is collected by

Next, an electrostatic latent image corresponding to the original image exposed by the light source (32) is formed and developed into a toner image by the developing device (15), and the toner image is transferred to the copy paper (P) by the transfer chiller (17). ), the copy paper (P) is peeled off by a separation charger (18), and then the residual toner on the photoreceptor drum (1) is collected by a cleaner (20). In this case, the charger (
The voltage applied to 12) is set to an appropriate value based on the detection signal of the surface potential sensor (13) during exposure of the simulated original (38), and the toner field attracted to the surface of the photoreceptor drum (1) is Mock original (38) Toner density sensor during exposure (19)
Since the value is set to an appropriate value based on the detection signal, high-quality copies can be obtained.

The above is an explanation when both sensors (13) and (19) are operating normally; if either one is not operating normally, the above control will cause the photosensitive drum (1) to
The toner m adsorbed on the surface of the toner m will deviate significantly from the appropriate value.

FIG. 2 is a flowchart showing the operation for determining an abnormal state when one of the sensors is not operating normally.

However, in the following explanation, if the detection signal of the surface potential sensor (13) is within the range of region R1 in FIG. If the detection signal of the sensor (19) is within the range R2 in FIG. 4, it is determined that the amount of toner adsorbed on the surface of the photosensitive drum (1) is an appropriate value.

In step (2), the detection signal Sv of the surface potential sensor (13) is obtained when the simulated original (38) is exposed, and in step (2), the detection signal Sv is obtained based on the graph of FIG. and calculate the surface potential VB corresponding to the detection signal SV, and step
In (2), it is determined whether the surface potential VB is within the range of the region R1. If it is above the region R1, an abnormality flag 2 is set in step (2), if it is below the region R1, an abnormality flag 1 is set in step (2), and if it is within the region R1, Without setting any flags, the next step is to determine if the value is less than Φ,
Process.

In step 2, the detection signal [)B of the toner density sensor (19) when the simulated original (38) is exposed is obtained;
In step 2, it is determined whether the detection signal QB is within the range of the detection signal region R2 corresponding to the surface potential region R1 (see FIG. 4).

If the detection signal QB is smaller than the lower limit value OL of the region R2, it is determined whether or not the abnormality flag 2 is set in step [share], and if the abnormality flag 2 is set, step 0 , the surface potential is abnormally high, and the high voltage unit (21) and charger (12)
) etc. is determined to be abnormal, and on the other hand, if the abnormality flag 2 is not set, in step @, the amount of toner is abnormally large, and the toner supply unit (not shown), toner concentration sensor (19), etc. It is determined that there is an abnormality.

Further, if the detection signal DB is larger than the upper limit value DH of the region R2, it is determined in step [phase] whether or not the abnormality flag 1 is set, and if the abnormality flag 1 is set, in step If the surface potential is abnormally low and the high voltage unit (21), charger (12), etc. are determined to be abnormal, and if the abnormality flag 1 is not set, then in step (2), the amount of toner is abnormally low. It is determined that the toner supply unit (not shown), toner 81 degree sensor (19), etc. are abnormal.

Moreover, if the detection signal DB is within the range of the above region R2,
In step [phase] (2), it is determined whether abnormality flag 1 or abnormality flag 2 is set.

If abnormality flag 1 is set, the output value of the surface potential sensor (13) is abnormal in step [phase], and the surface potential sensor (13), control circuit (not shown), etc. are abnormal. If it is determined that there is an abnormality and the abnormality flag 2 is set, it is determined in step [phase] that the surface potential sensor (13), the control circuit (not shown), etc. are abnormal. On the other hand, if neither flag is set,
In the step [phase] the dove replenishment motor (not shown)
etc., toner replenishment m is performed, and then in step (3), a copying operation is performed at an appropriate density.

In summary, the above discrimination and processing are performed for each copying operation, and the toner density is controlled only when the detection signals of both sensors are within the appropriate range, and the copying operation is performed at the appropriate density. If the detection signal of the sensor is outside the proper range, it is determined that the high voltage unit (21), charger (12), etc. are abnormal, and only the detection signal of one of the sensors is outside the proper range. In this case, it is determined that the sensor, control unit, etc. that output the detection signal outside the appropriate range is abnormal.

Therefore, when there is an abnormality in the sensor, control unit, etc., the toner density is controlled based on the abnormal detection signal to prevent the production of incorrect copies and the wastage of toner, copy paper, etc. It can definitely be prevented.

It should be noted that the present invention is not limited to the above-mentioned embodiments. For example, if a sensor is installed to detect the remaining amount of toner in the developing device (15), and the detection signal of the toner concentration sensor is outside the appropriate range, , it is possible to determine whether or not the amount of toner in the developing device (15) is abnormal, and it is possible to reliably determine whether the toner concentration sensor (19) is abnormal. Photosensitive drum (1
) instead of detecting the surface potential of the photoreceptor drum (1).
The dark potential of the present invention can be detected, and various other design changes can be made without changing the gist of the present invention.

<Effects> As described above, the present invention mounts a surface potential sensor and a toner concentration sensor in close proximity to a photoreceptor, and detects whether an abnormality is in the copying function execution section or the sensor section based on the detection signals of both sensors. This has the unique effect of being able to reliably prevent the inconvenience of performing inappropriate surface potential control or the like based on an abnormal detection signal by determining the abnormal state of the sensor section.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the main parts of a copying machine, FIG. 2 is a flowchart, FIG. 3 is a diagram showing characteristics of a surface potential sensor, and FIG. 4 is a diagram showing characteristics of a toner degree sensor.

Claims (1)

[Claims] 1. Place the surface potential sensor close to the photoreceptor. Attach the toner density sensor and both sensors. Based on the detection signal of Determine whether it is normal or there is an abnormality in the sensor part. A method for determining an abnormal state of a copying machine. 2. Detection of abnormal state of detection signals of both sensors If the signal is The scope of the above claims determined to be A method for determining an abnormal state of a copying machine according to item 1. 3. Only the detection signal of one sensor is abnormal. If the signal is a detection signal of an abnormal condition, The sensor or sensor that outputs the detection signal The above characteristics are determined to be an abnormality in the control unit. Abnormality of the copying machine as set forth in claim 1 Status determination method.