JPH0863082A - Printing device - Google Patents

Abstract

PURPOSE: To provide a printing device which is capable of printing in the case where the aimed potential is not obtained even in the case where the voltage impressed on the pre-electrifier reaches a specified limit value, whose cause is attributed to environmental conditions. CONSTITUTION: The voltage control means 7 controls the voltage impressed on the pre-electrifier 2 which uniformly electrifies the photosensitive drum 1 based on the temperature and humidity detected by the temperature/humidity detecting means 4, 5 so that the aimed potential preset in the memory 6 is obtained. The judging means 9 judges whether the present environmental conditions are within the regulation values which give the operation-securing environmental conditions (e.g. temperature 5 to 35 deg.C, humidity: 20 to 80%) prescribed in the design specification of this device or not. When the judgement is 'No', it is judged that printing is possible. Otherwise, it is judged that the device is abnormal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus using an electrophotographic system. In a printing device in which the voltage applied to the pre-charger is controlled according to the temperature and humidity inside the device, if the voltage applied to the pre-charger reaches a specified limit value, the printing operation is considered to be abnormal and the printing operation is stopped. It has been deterred.

However, when the cause is the environment in which the device is used, some users want to print even if the print quality is somewhat poor, and there is a demand for improvement.

[0003]

2. Description of the Related Art A printing apparatus adopting an electrophotographic system is constructed by arranging a pre-charging device, an exposing device, a developing device, a transfer device, a peeling device, a cleaning device, a static eliminator, etc. around a photosensitive drum. .

The surface of the photosensitive drum is uniformly charged by corona discharge by a pre-charger, and then an exposure light corresponding to a character or a figure to be printed is irradiated to form an electrostatic latent image. Developed).

After that, a sheet is supplied on the toner image,
The toner image on the photosensitive drum is transferred onto the paper by corona discharge from the back surface of the paper. The paper adsorbed on the photosensitive drum is peeled off and fixed by heating to complete the printing. The surface of the photosensitive drum that has been transferred is cleaned and discharged,
Further, the same steps are repeated.

In such a printing apparatus, since the charging characteristic of the photosensitive drum depends on the usage environment of the apparatus, it is necessary to detect the temperature inside the apparatus and adjust the voltage applied to the pre-charger accordingly. Thus, the surface potential of the photosensitive drum is controlled to a predetermined value.

When the voltage applied to the pre-charger reaches a limit value, that is, when the maximum voltage is applied to the power source or for safety reasons, a predetermined surface potential cannot be obtained.
Generally, the printing operation is stopped on the assumption that the apparatus has some abnormality.

[0008]

Here, when the predetermined surface potential cannot be obtained even when the voltage applied to the pre-charger reaches the limit value, the device is used except when an abnormal condition occurs. If the environment is not an operation-guaranteed environment according to the design specifications, for example, the temperature and humidity may be abnormally high, which may cause a decrease in surface resistance due to moisture absorption on the surface of the photosensitive drum.

In this case, the print quality may be deteriorated to some extent, but since the apparatus is not faulty, if the user allows or desires it, there is no problem even if printing is possible. Does not happen.

However, conventionally, if the predetermined surface potential is not obtained even when the voltage applied to the pre-charger reaches the limit value, it is uniformly judged that the apparatus is abnormal and the printing operation is stopped. Therefore, there is a problem that the request cannot be met.

Further, when the apparatus becomes abnormal, it is necessary to perform maintenance, but this is not due to the failure of the apparatus, but printing can be performed if the usage environment becomes proper, so that it is wasteful. Is not efficient.

The present invention has been made in view of the above circumstances, and an object thereof is to obtain a predetermined surface potential even when the applied voltage to the pre-charger reaches a limit value. The purpose of the present invention is to provide a printing device capable of performing printing by determining whether this is due to a device abnormality or a use environment, and if it is due to the use environment.

[0013]

Description will be made with reference to a block diagram showing a principle configuration of the present invention shown in FIG. The printing apparatus of the present invention includes a photosensitive drum 1, a pre-charging device 2 that uniformly charges the surface of the photosensitive drum 1, a potential detection unit 3 that detects the surface potential of the photosensitive drum 1, and a temperature near the photosensitive drum 1. Temperature detecting means 4 for detecting the temperature, humidity detecting means 5 for detecting the humidity in the vicinity of the photosensitive drum 1, and target potential storing means 6 for storing a target potential preset corresponding to the temperature and the humidity.
And the target potential corresponding to the temperature and humidity detected by the temperature detecting means 4 and the humidity detecting means 5, respectively.
It is provided with a voltage control means 7 for controlling the voltage applied to the pre-charger 2 so that the potential detected by the potential detection means 3 becomes the target potential.

Further, the voltage applied to the specified value storage means 8 and the pre-charger 2 in which specified values indicating the specified temperature range and the specified humidity range for the operating environment of the apparatus are set in advance reach a predetermined limit value. At this time, the temperature detecting means 4 and the humidity detecting means 5 are provided with a judging means 9 for judging whether or not the detected temperature and detected humidity are within the range of the specified value. And
When the determination unit 9 determines that the detected temperature and the detected humidity are within the specified value range, the device is in an abnormal state, and the detected temperature or the detected humidity is outside the specified value range. Is set to a printable state.

In addition to the above structure, the following structure can be adopted. That is, even when the input unit 10 for selectively inputting whether the device is abnormal or printable is provided, and the determination unit 9 determines that the detected temperature or the detected humidity is out of the specified value range, If the selection by the input means is an abnormal device, the device is in an abnormal state.

A display means 11 is provided for displaying a warning when the determination means 9 determines that the detected temperature or the detected humidity is out of the specified range. When the determination unit 9 determines that the detected temperature or the detected humidity is out of the range of the specified value, the time counting unit 12 that counts a preset fixed time is provided, and the determination unit 9 includes the time counting unit. Waiting for the elapse of a fixed time by 12, further determination is made.

[0017]

In the printing apparatus, the specified environment in the design specifications is predetermined, and in the use in the specified environment, good printing can be performed as long as there is no apparatus failure.

Therefore, when the voltage applied to the pre-charger reaches the limit value and the predetermined surface potential is not obtained during use in such a specified environment, it is determined that the cause is some abnormality in the device. can do.

On the other hand, if the predetermined surface potential is not obtained even when the voltage applied to the pre-charger reaches the limit value during use in a environment other than the specified environment, the cause is due to the environment.
That is, it can be determined that the surface resistance is reduced due to moisture absorption of the photosensitive drum.

In the present invention, the above-mentioned specified value storage means 8 and
The determination means 9 determines whether or not the cause is due to the environment, and when the cause is due to the environment, printing is enabled, and thus it is possible to cope with a user who allows some deterioration in print quality. I did it.

For a user who does not tolerate the deterioration of print quality, this can be dealt with by setting the input means. Further, the display means 11 notifies the operator of a warning, and the time counting means 12 makes the determination again after a certain period of time elapses, thereby making it possible to wait for stabilization of the installation environment of the device to make a more reliable determination. .

[0022]

Embodiments of the present invention will be described below with reference to the drawings. In the following description, components that are substantially the same as those in FIG. 1 will be designated by the same reference numerals.

FIG. 2 is a diagram showing the overall construction of a printing apparatus to which the present invention is applied. In the figure, 1 is a photosensitive drum, and around the photosensitive drum 1, a pre-charger (corotron) 2, an exposure device 13, a developing device 14, a transfer device (corotron) 15, a peeling device (corotron) 16, and a cleaning device. A container 17, a static elimination lamp 18, etc. are arranged. Also, 19
Is a fixing device, 20 is a sheet, and 21 is a stacker of sheets after printing. Reference numeral 22 is a page buffer, and 23 is a sheet conveying means.

The surface of the photosensitive drum 1 is first uniformly charged by corona discharge by the pre-charger 2. The exposure device 13 irradiates the uniformly charged photosensitive drum 1 with a laser beam, which is sent from the host 24 and stored in the page buffer 22, corresponding to an image to be printed such as characters and figures.
As a result, an electrostatic latent image is formed on the photosensitive drum 1. This electrostatic latent image is developed by the developing device 14 with toner (developer).

Corresponding to the toner image on the photosensitive drum 1, the sheet 20 is conveyed by the conveying means 23, and the toner image on the photosensitive drum 1 is transferred onto the sheet 20 by corona discharge from the back surface of the sheet 20 by the transfer unit 15. It After transfer, peeler 1
The paper 20 is peeled off from the photosensitive drum 1 by the corona discharge by 6, and is heat-fixed by the fixing device 19 to complete the printing. The paper 20 on which printing has been completed is stored in the paper stacker 21.
Sent to

On the surface of the photosensitive drum 1 which has been transferred, the cleaning device 17 removes residual toner, paper dust and the like, and the charge is removed by the charge eliminating lamp 18, and these steps are repeated. The toner removed from the photosensitive drum 1 by the cleaning device 17 is sucked by air.

FIG. 3 is a block diagram showing the structure of the main part of this embodiment. Reference numeral 31 is a control means, and the control means 31 includes a microprocessing unit (MPU) 32, a memory (ROM, RAM) 33, and an outport (OUT-PO).
RT) 34 and import (IN-PORT) 35.

A surface potential detector (potential detecting means) 3 and temperature / humidity detectors (temperature detecting means, humidity detecting means) 4, 5 are connected to the import 35, and the out port 34 is connected.
A high voltage power supply 36 for applying a voltage to the pre-charger 2 and a display means 37 for notifying an operator of various information such as a device abnormality are connected to the.

The memory 33 corresponds to the target potential storage means 6 and the prescribed value storage means 8 shown in FIG. 1, and the target potential table and the prescribed value are preset. Further, the limit value of the high voltage power supply 36 is also preset. The microprocessing unit 32 realizes the functions of the voltage control unit 7, the determination unit 9, and the other units shown in FIG. 1 by appropriately executing the program stored in the memory 33.

In this embodiment, the surface potential detector 3
Is provided on the downstream side of the pre-charger 2, and the temperature / humidity detectors 4 and 5 are provided inside the photosensitive drum 1. Next, the processing of the control means 31 (voltage control means 7 and determination means 9 in FIG. 1) will be described with reference to the flow chart shown in FIG.

First, when the power of the printing apparatus is turned on (ST1), the control means 31 causes the temperature / humidity detectors 4 and 5 to operate.
The target potential table of the memory 33 is searched based on the detected temperature and the detected humidity detected by, and the target potential corresponding thereto is determined (ST2, 3). The surface potential of the photosensitive drum 1 is set in advance in the target potential table in correspondence with the temperature and the humidity, and for example, the temperature is 40 ° C. and the humidity is 50.
In%, data such as 900 V is set as the target potential.

Next, the control means 31 controls the high-voltage power supply 36 to apply a voltage corresponding to the target potential to the pre-charger 2 (ST4), and the surface of the photosensitive drum 1 measured by the surface potential detector 3 is measured. The electric potential is taken in (ST5). The measured surface potential is compared with the target potential (ST6), and when the measured surface potential is the target potential, the printable state is set (ST7).

When the measured surface potential is not the target potential, the voltage applied to the pre-charger 2 is changed (increased) (ST8). As a result of increasing the applied voltage, it is judged whether or not it has reached the limit value set in the memory 33, that is, the maximum voltage from the viewpoint of the capability of the high voltage power supply 36 or safety (ST9), and has not reached. In that case, the process returns to ST4.

When the applied voltage reaches the limit value,
Temperature / humidity detectors 4 and 5 detect temperature and humidity,
This is compared with the specified value in the memory 33 (ST10). The stipulated value is a numerical representation of the operation guarantee environment in the design specifications of this printing apparatus. Specifically, for example, the temperature is 5 ° C to 35 ° C and the humidity is 20 to 80 ° C.
Like% RH.

In ST10, when both the detected temperature and the detected humidity are within the specified range, the reason why the surface potential does not reach the target potential is that some abnormality has occurred in the device. It is judged that the device is in an abnormal state,
The printing operation is suppressed (ST11). When either or both of the detected temperature and the detected humidity are outside the range of the specified value, it is determined that the cause of the surface potential not reaching the target potential is the environment, and the printable state is set ( ST
7).

The above flow will be specifically described. When the power is turned on, the temperature is 40 ° C., the humidity is 50%, the target potential corresponding thereto is 900 V, and if the surface potential after the voltage application is 800 V, the surface potential has not reached the target potential. The control means 31 raises the applied voltage.

The applied voltage is 1000, which is the limit value.
When the temperature reaches V, the temperature and humidity are detected again, and when there is no change from when the power is turned on, the temperature is outside the range of the specified value. In this case, the printable state is set. However, in this case, since the surface potential has not reached the target potential, the print quality is not guaranteed, but it may be sufficient depending on the purpose of printing such as provisional printing for checking.

FIG. 5 is a flowchart showing the processing when the input means 10 shown in FIG. 1 is provided, which is a modification of part of the processing shown in FIG. The same processes as those in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted.

That is, the processes from ST1 to ST9 in FIG. 4 are the same, and in ST10, when the detected temperature or the detected humidity is out of the range of the specified value, the printable state is not immediately input but the input is performed. When the designation by the means (setting switch) 10 is judged (ST12), the printing is enabled only when the designation is "ON" (ST7), and when the designation is "OFF", the device is in an abnormal state. (ST11).

Depending on the user, there are cases in which the print quality is not guaranteed and the user cannot be satisfied. In this case, since the printable state should not be set, the setting switch 10 is set to "OFF". This is to deal with this.

FIG. 6 is a flowchart showing a process when the time counting means 12 in FIG. 1 is provided, which is a part of the process of FIG. 4 improved. The same processes as those in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted.

That is, the processing from ST1 to ST9 in FIG. 4 is the same, and in ST10, when the detected temperature or humidity is out of the range of the specified value, the printable state is not immediately set but the time counting is performed. The means (timer) 12 counts a certain period of time, waits for a certain period of time to elapse (ST13), detects temperature and humidity again, and compares this with a specified value (S).
T14), the printable state is set only when it is out of the specified value range (ST7), and the device abnormal state is set when it is in the specified value range (ST11).

Generally, in an office or the like in which a printing apparatus is installed, the air conditioning equipment in the office is turned on and the printing apparatus is turned on when the work is started until the indoor environment stabilizes. Takes time. Therefore, when the power is turned on, it is often outside the specified value range, and the reliability of the determination as to whether the cause of the surface potential not reaching the target potential is a device failure or the environment is low.

Therefore, the printable state is set only when the value is still outside the range of the specified value even after a certain period of time has passed. When the cause is a device failure, there is a problem in making the printable state, and thus such a defect is compensated. The fixed time is preset as a time sufficient for stabilizing the indoor environment.

FIG. 7 is a flowchart showing the processing when the display means 11 in FIG. 1 is provided, which is a modification of part of the processing shown in FIG. The same processes as those in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted.

That is, the processing from ST1 to ST9 in FIG. 4 is the same. In ST10, when the detected temperature or the detected humidity is out of the range of the specified value, first, the temperature or the humidity is displayed on the display means 11 as the specified value. Is displayed, the operator is warned to that effect (ST15), and then the printable state is set (ST7).

Next, it is further judged whether the detected temperature or the detected humidity is within the specified value range or outside the specified value range. If the detected temperature or detected humidity is outside the specified value range, the judgment is repeated (ST16). When it is within the range of the specified value, the warning display displayed on the display means 11 is cleared (ST17). In ST10, when the detected temperature and the detected humidity are within the range of specified values, the device is in an abnormal state (ST11).

According to the various embodiments described above, when the detected temperature or the detected humidity is out of the range of the predetermined specified value,
It was determined that the cause of the surface potential not reaching the target potential was due to the environment, and in this case, printing was enabled.
Therefore, it becomes possible for a user who allows a slight deterioration in print quality to perform printing.

A user who does not tolerate such deterioration of print quality can be dealt with by setting the input means (setting switch) 10. Further, by providing the time counting means (timer) 12, it is possible to improve the reliability of the determination as to whether the cause of the surface potential not reaching the target potential is the device abnormality or the environment.

By providing the display means 11, the operator can confirm that the current environment does not meet the predetermined operation guarantee environment, that is, if printing is performed in this state,
It can be recognized that the print quality is slightly deteriorated, and the operator can determine whether or not to print.

[0051]

Since the present invention is configured as described above, when the predetermined surface potential cannot be obtained even when the voltage applied to the pre-charger reaches the limit value, whether this is due to an abnormality in the device or the operating environment. It is possible to provide a printing device capable of performing printing depending on the usage environment.

[Brief description of drawings]

FIG. 1 is a block diagram showing a principle configuration of the present invention.

FIG. 2 is a diagram showing an overall configuration of an embodiment of the present invention.

FIG. 3 is a block diagram showing a main configuration of an embodiment of the present invention.

FIG. 4 is a flowchart showing a process of an embodiment of the present invention.

FIG. 5 is a flowchart showing a process of another embodiment of the present invention.

FIG. 6 is a flowchart showing the processing of another embodiment of the present invention.

FIG. 7 is a flowchart showing a process of another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Precharger 3 Potential detection means 4 Temperature detection means 5 Humidity detection means 6 Target potential storage means 7 Voltage control means 8 Specified value storage means 9 Judgment means 10 Input means 11 Display means 12 Time counting means

Claims (4)

[Claims] 1. A printing apparatus adopting an electrophotographic system, comprising: a photosensitive drum; a pre-charger for uniformly charging the surface of the photosensitive drum; a potential detecting means for detecting the surface potential of the photosensitive drum; A temperature detecting means for detecting the temperature in the vicinity of the drum, a humidity detecting means for detecting the humidity in the vicinity of the photosensitive drum, and a target potential storing means for storing a target potential preset corresponding to the temperature and the humidity. A target potential corresponding to the temperature and humidity detected by the temperature detecting means and the humidity detecting means is taken out from the target potential storing means, and the pre-charger is set so that the detected potential by the potential detecting means becomes the target potential. Voltage control means for controlling the voltage applied to the device, specified value storage means in which specified values indicating the specified temperature range and specified humidity range for the operating environment of the device are preset, and the pre-charger is marked. When the applied voltage reaches a predetermined limit value, the temperature detection means and the humidity detection means include a determination means for determining whether the detected temperature and the detected humidity are within the range of the specified value. When it is determined by the means that the detected temperature and the detected humidity are within the range of the specified value, the device is in an abnormal state, and when it is determined that the detected temperature or the detected humidity is outside the range of the specified value. A printing apparatus, which is in a printable state. 2. The printing apparatus according to claim 1, further comprising an input unit for selectively inputting whether the device is abnormal or capable of printing, and the determination unit detects the detected temperature or the detected humidity within the specified range. A printing apparatus, wherein even if it is determined that the printing apparatus is outside, if the selection by the input means is a printing apparatus abnormality, a printing apparatus abnormal state is set. 3. The printing apparatus according to claim 1, further comprising a display unit that displays a warning when the determination unit determines that the detected temperature or the detected humidity is outside the specified value range. A printing device characterized by the above. 4. The printing apparatus according to claim 1, wherein when the determination unit determines that the detected temperature or the detected humidity is outside the range of the specified value, a preset constant time is counted. A printing apparatus, comprising: a time counting unit, wherein the determination unit waits for a certain period of time by the time counting unit to make a further determination.