JP3551389B2 - High voltage abnormality detection method for electrostatic recording device - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to electrical control of an electrostatic recording device provided with a high-voltage power supply, and more particularly to a method of detecting an abnormality when an abnormality occurs in the high-voltage power supply of the electrostatic recording device.
[0002]
[Prior art]
2. Description of the Related Art In an electrostatic recording apparatus that forms an image by an electrophotographic method, charging, development, transfer, separation, and the like are performed using a high-voltage power supply. In this case, for example, due to foreign matter in the vicinity of the electrode performing corona charging, a space for insulation and a creepage distance cannot be secured, and a high-voltage output leaks near the electrode. Due to this leak discharge, the transfer paper, toner and a portion having low flame retardancy burn, and there is a problem of safety.
[0003]
Therefore, as a safety measure in such a case, a method of detecting a leak of the high-voltage power supply and forcibly stopping the high-voltage power supply is generally adopted. The abnormality of the high voltage power supply is canceled by turning off the main power supply once .
[0004]
However, for a high pressure that does not directly affect the image or a high output that has a low output and is used in a place where ignition does not occur even if a leak occurs, stop the high pressure output with a single leak and stop the machine unnecessarily. This is undesirable from the viewpoint of user convenience.
[0005]
[Problems to be solved by the invention]
High-voltage power supplies used in electrostatic recording devices include power supplies that output high voltage and are of high importance in terms of safety, while power supplies that are of low importance in terms of safety, for example, do not cause a fire or the like immediately even if there is a leak. There is also. Some power supplies make it impossible to record an image immediately due to a leak, while others have a slightly lower reliability and the like but can continuously record an image due to a leak.
[0006]
The present invention relates to an electrostatic recording apparatus in which a recording operation is not stopped immediately by a leak discharge that can be immediately restored for a high-voltage power supply that has a low importance in safety and that does not affect an image even if an error occurs. It is an object of the present invention to provide a method for detecting a high-pressure abnormality.
[0007]
[Means for Solving the Problems]
The above object is achieved, if it is determined that the abnormal high-pressure abnormality output by detecting the output current other than the primary high pressure supply, to stop the output of high voltage power supply, the recording operation is stopped is displayed on the display section an abnormal state In the high pressure abnormality detection method of the electrostatic recording device ,
When the abnormality detection circuit detects the abnormality of the high voltage output,
An abnormal signal for stopping the output of the high-voltage power supply is input to the CPU via the latch circuit to stop the output of the high-voltage power supply,
While holding the output stop state of the high voltage power supply by the latch circuit,
A high-pressure abnormality page counter that counts the high-pressure abnormality output that occurs once in one page is counted up,
Using the OFF control signal from the CPU for the high-voltage power supply to reset the latch circuit,
The high-voltage power supply is driven by turning on the control signal,
The timing of outputting the high voltage power supply is the timing at which writing between recording pages is not performed,
By repeating the above operation, when the count value of the abnormal page counter becomes a value that is arbitrarily set two or more times continuously,
For the first time, the recording operation is interrupted and stopped by judging that the high-voltage power supply cannot be restored and that the high-voltage output is abnormal,
Display an error display on the display,
If no abnormal output has occurred during the period from the start of counting of the abnormal page counter to the set value, the abnormal page counter is cleared.
This is achieved by a method for detecting a high-pressure abnormality in an electrostatic recording device.
[0009]
[Action]
If the present invention is, for high pressure is less important in terms of safety, as the structure for releasing the high voltage power supply failure state by high pressure of ON / OFF control signals, repeatedly OFF and ON control signals, which continued for more than a certain number of times, a high pressure FIG. 6 is a block diagram of a high-voltage power supply abnormality detection circuit, in which FIG. 6A shows a conventional circuit configuration, and FIG. 6B shows a conventional circuit configuration. An example is shown, in which a latch circuit is reset by a high-voltage ON / OFF control signal.
[0010]
【Example】
FIG. 1 is a sectional view showing the configuration of a color image forming apparatus as an embodiment of the electrostatic recording apparatus of the present invention.
[0011]
First, the configuration and operation will be described.
[0012]
In the figure, reference numeral 10 denotes a photosensitive drum serving as an image carrier, which is obtained by coating an OPC photosensitive layer on the drum, is grounded, and is driven and rotated clockwise. 12 Corona by high pressure in the scorotron charger current control is performed by the DC power source, the grid and the corona discharge wire which uniform charging of V _H is the potential held in the V _G the photosensitive drum 10 peripheral surface for charging Given by the discharge. Prior to the charging by the scorotron charger 12, in order to eliminate the history of the photoconductor up to the previous print, exposure by the PCL 11 using a light emitting diode or the like is performed to eliminate the charge on the peripheral surface of the photoconductor.
[0013]
After the photosensitive member is uniformly charged, image exposure based on the image signal is performed by the image exposure means 13. The image exposure means 13 scans the optical path by a reflecting mirror 132 through a rotating polygon mirror 131, an fθ lens, and the like, using a laser diode (not shown) as a light emitting light source. The rotation (sub-scan) of the photosensitive drum 10 A latent image is formed. In this embodiment, the character portion is exposed to form a reversal latent image such that the character portion has a lower potential _VL .
[0014]
Around the periphery of the photoconductor drum 10, there are provided developing devices 14 each containing a developer containing a toner such as yellow (Y), magenta (M), cyan (C), and black (K) and a carrier. The development of the first color is performed by a developing sleeve 141 which rotates while holding a developer with a built-in magnet. The developer consists of a carrier with ferrite as the core and an insulating resin coated around it, and a toner with polyester as the main material and a pigment according to the color, a charge control agent, silica, titanium oxide, etc. The agent is regulated to a layer thickness of 300 to 600 μm on the developing sleeve 141 by the layer forming rod, and is conveyed to the developing area.
[0015]
As 0.4~1.0mm the developing sleeve 141 a gap between the photosensitive drum 10 is greater than the layer thickness (developer) in the developing zone, the _{V AC} of the AC Baaisu and _{V DC} by a high voltage power supply for development during this time A DC bias is superimposed and applied. V _DC and _{V H,} for charging the toner are the same _polarity, the toner given the opportunity to leave from the carrier by _{V AC} is not adhere to a portion of the high _{V H} of potential than _{V DC,} potential than _{V DC} Adhered to the _VL portion having a low value, and visualization (reversal development) is performed.
[0016]
After the visualization of the first color is completed, the image forming process for the second color is started, the uniform charging is again performed by the scorotron charger 12, and the latent image based on the image data of the second color is formed by the image exposure unit 13. At this time, the charge removal by the PCL 11 performed in the image forming process of the first color is not performed because the toner attached to the image portion of the first color scatters due to a sharp drop in the surrounding potential.
[0017]
A latent image similar to that of the first color is formed on the portion of the photoconductor having the potential of _{VH which has} the potential of _VH again over the entire surface of the photoconductor drum 10 without the image, and development is performed. the potential difference in the portion to perform re-development to part there is an image of the first color, 1 V _M by color toner adhering to the charge possessed by the shading and toner itself _'latent image is formed, V _DC and V _M' Is performed in accordance with. In the overlapping portion of the first color image and the second color image, if the development of the first color is performed by creating a _VL latent image, the balance between the first color and the second color is lost. sometimes an intermediate potential to be _{H> V} M> _{V L.}
[0018]
For the third and fourth colors, the same image forming process as that for the second color is performed, and a visible image of four colors is formed on the peripheral surface of the photosensitive drum 10.
[0019]
On the other hand, the recording paper P fed from the paper feed cassette 21 by the paper feed mechanism 22 is fed to the transfer area by the transfer belt device 30 having the transfer belt 31 stretched, and the recording paper P The color images are collectively transferred onto the recording paper P.
[0020]
The transfer belt 31 is an endless rubber belt having a resistance of 10 ⁶ to 10 ¹⁴ Ω · cm and a thickness of 0.4 to 1.0 mm and formed of an outer FLC layer of a urethane rubber substrate. And high resistance belts such as those coated with these films.
[0021]
And voltage V _PC is applied by a high-voltage power supply DC as pre-transfer charging means with respect to the axis 32a of the upstream-side holding roller 32 of the holding rollers 32 and 33 for stretching the transfer belt 31, this axis 32a A conductive brush 34 as a means for applying electric charge to the recording paper P is grounded at a position where the recording paper P is installed via the transfer belt 31, or grounded via a non-linear element resistor. The fed recording paper P enters between the brush 34 and the transfer belt 31, charges are injected into the recording paper P from the brush 34, and an attraction force is applied between the recording paper P and the transfer belt 31. Occurs. Thereafter, the recording paper P enters a nip (transfer area) 35 formed by the photosensitive drum 10 and the transfer belt 31, and is supplied from a high-voltage power supply having a polarity opposite to that of the high-voltage toner whose current is controlled from the rear surface of the transfer belt 31. A transfer electric field is applied to the corona discharger 36 or a bias roller instead of the corona discharger 36, and a multicolor image is transferred onto the recording paper P.
[0022]
The recording paper P separated from the photoreceptor drum 10 is subjected to AC corona discharge by an AC high voltage power supply using an axis 33a of a downstream holding roller 33 on which a transfer belt 31 is stretched as a counter electrode, or AC corona discharge. The sheet is separated from the transfer belt 31 while receiving the discharge. 37 removes toner adhered to the transfer belt 31 rotated by the cleaning blade. The transfer belt 31 of the transfer belt device 30 is separated from the photosensitive drum 10 around the shaft 33a of the holding roller 33 on the downstream side during the formation of a multicolor image.
[0023]
The recording paper P holding the multicolor image separated from the transfer belt device 30 is conveyed to a fixing device 23 including at least two pressure rollers having a heater inside one of the rollers, and heat and pressure are applied between the pressure rollers. Is added, the adhered toner is melted, fixed on the recording paper P, and then discharged out of the apparatus.
[0024]
The residual toner remaining on the peripheral surface of the photoconductor drum 10 after the transfer is subjected to static elimination by a static eliminator 15 using an AC corona discharge by a high-voltage AC power supply, and then enters a cleaning device 16 or a rubber material that contacts the photoconductor. Is scraped into the cleaning device 16 by a cleaning blade 16a, and discharged by a screw or the like, and stored in a collection box. The neutralizer 15 can also function to neutralize the recording paper depending on its arrangement.
[0025]
The photosensitive drum 10 from which the residual toner has been removed by the cleaning device 16 is uniformly charged by the above-described scorotron charger 12 after being exposed by the PCL 11, and enters the next image forming cycle. During the formation of the multicolor image, the cleaning blade 16a is separated from the surface of the photoconductor, and the AC static elimination by the static eliminator 15 is kept OFF.
[0026]
FIG. 3A shows a flowchart of the entire electrostatic recording apparatus. When the printer main body is turned on, the entire system is initialized, and idling processing is continuously executed until a print execution command comes. When a print execution command is received in this state, the printing process is repeatedly executed, and when the printing operation is completed, the process returns to the idling process.
[0027]
FIG. 3B shows an example of the print processing in FIG. 3A. The print processing is a collection of individual routines including a high-pressure abnormality determination routine to be described after the present invention. The software is configured to perform the print processing once every 5 msec or at a time interval of, for example, 5 msec.
[0028]
In the electrostatic recording apparatus of the present invention, there is no danger of ignition even if there is a leak in the charged portion, as in, for example, a pre-transfer charging unit, and the reliability of conveyance of the recording paper is reduced (jam etc. may occur). For a high-voltage power supply that does not affect the image, when the abnormality of the high-voltage output is detected, means for stopping the output of the high-voltage power supply and holding the stopped state, and controlling the stopped state by a control signal of the high-voltage power supply Is provided by turning off the control signal, and the timing of turning on the control means and outputting the high-voltage power supply is a timing at which writing between the recording pages is not performed , and repeatedly turns off and on while the high-voltage output is abnormal. A counter for counting the operation is provided, and when the counter continuously exceeds an arbitrary value, it is determined that the high voltage output is abnormal for the first time, and the recording operation is interrupted and stopped. It is intended to display the abnormality on the display unit using a liquid crystal or the like provided in the.
[0029]
FIG. 2 is a block circuit diagram showing a control system of the present invention. FIG. 4 is a flowchart of a high-voltage abnormality determination A of the present invention in which a determination process is performed by a CPU. It is a time chart figure of an OFF control signal. FIG. 6 is a diagram illustrating a relationship between an abnormal output waveform, a detection signal, and an abnormal output when abnormal discharge occurs in the high-voltage output. Although FIG. 6 shows a case where abnormal discharge has occurred with respect to the DC high-voltage output, the same applies to AC.
[0030]
The description will be made mainly on the flowchart of the high-pressure abnormality determination A in FIG. The CPU 201 shown in FIG. 2 checks whether or not the target high-voltage power supply is operating according to the high-voltage abnormality determination routine (F1). When the high-voltage output is being performed, is the abnormality flag = 1? A check is made as to whether or not it is (F2). A high-voltage output is generated from the high-voltage generator 202B of the high-voltage power supply unit 202 shown in FIG. 7B, but the abnormal-state flag is not set and the high-voltage output waveform has an abnormal discharge state as shown in FIG. Then, a detection signal as shown in FIG. 7B is sent from the high voltage generation unit 202B to the abnormality detection circuit 202C, and an abnormality signal is output from the latch circuit 202D to the CPU 201. When it is checked whether an abnormal signal is input (F3), if an abnormal signal is input to the CPU 201, the CPU 201 sets an abnormal flag (F4), and stops outputting the high voltage output as shown in FIG. Is performed, and the abnormal page counter of the RAM memory 204 is counted up (F5). Next, the counted value is compared with a comparison value stored in advance in the ROM 203, for example, 200 pages (F6), and when the count value becomes equal to 200 pages (FIG. 5 (4)), the stop processing of the recording operation is performed. (F7A), and the display unit 205 displays "High voltage abnormality occurred" (F8A).
[0031]
If the counted value does not reach 200 pages, it is checked whether or not the writing operation for forming an image has been completed (F7). If the writing operation has not been completed, the flow returns to F1 of the high voltage abnormality determination routine described above. When the write operation has been completed, it is checked whether or not the abnormal flag = 1 in the high voltage output state (F8). If the abnormal flag has not been set to 1, the counter has been counted up first. The abnormal page counter is cleared (F9A), then the abnormal flag is cleared (F10), and the process returns to F1 of the high-pressure abnormality determining routine.
[0032]
Also though the write operation is completed, should be noted when an abnormal flag = 1 performs OFF and ON operation by ON / OFF control signal from the CPU 201 (FIG. 5 (2)), to release the latch circuit, a high pressure The output is output again (F9), and the process returns to F1 of the high pressure abnormality determination routine with the abnormality flag cleared (F10).
[0033]
Here, the reason why the abnormality flag is provided is that, in the high-pressure abnormality determination routine shown in FIG. 4, this processing is performed once, for example, every 1 to 5 msec as a part of the print processing flowchart shown in FIG. Therefore, during this time, the abnormal state continues and counts up steadily. Therefore, when the abnormal flag is set (abnormal flag = 1), the routine is not performed and the count is not incremented.
[0034]
The high-voltage power supply to be described above is a high-voltage power supply that does not damage the machine even when the high-voltage output stops, and the control during the recording operation is as follows.
[0035]
(1) Abnormal discharge occurs at the high voltage electrode. The high voltage abnormality detection circuit 202C outputs an abnormality signal and stops the high voltage power supply.
[0036]
(2) CPU is an abnormality signal is inputted, and counts up the abnormal page counter. The record page is completed, the non-image area between successive recording page, ON the reset high voltage power supply latch circuit 202D by ON once and OFF the high pressure ON / OFF control signal of the ON state again I do.
[0037]
(3) If a continuously high abnormal discharge occurs, (2), (3) Operation repeating, when the abnormal page counter value is equal to or greater than a set value, it determines that the abnormal high-pressure output system does not return To stop the recording operation, stop the machine, and display a warning.
[0038]
(4) If abnormality counter reaches the recording operation ends standby state before reaching the set point, also, if even one page abnormal discharge in continuous printing did not occur, the content of the abnormal page counter clear.
[0039]
Although the comparison value is 200 pages in the embodiment, this value may be changed according to the machine configuration or process conditions, or a plurality of values may be switched and compared according to conditions.
[0041]
On the other hand, if a high voltage power source such as a charging unit, a developing bias, a transfer unit, etc. causes a leak or the like, no image is formed, or if there is a risk of fire, it is necessary to immediately stop the operation. The high-pressure abnormality determination B routine shown in FIG. 8 indicates this. The high-pressure abnormality determination A routine and the high-pressure abnormality determination B routine of the present invention are incorporated into the print processing flowchart of FIG.
[0042]
【The invention's effect】
In the conventional image recording apparatus, the recording operation has been stopped by an error that does not affect the image or a leak discharge that can be immediately restored. Since the countermeasures were taken separately for abnormalities, the running performance of the machine was greatly improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a configuration of an electrostatic recording device according to the present invention.
FIG. 2 is a block circuit diagram showing a control system of the present invention.
3A is a flowchart of the overall control, and FIG. 3B is a flowchart of a printing process.
FIG. 4 is a flowchart of a high-pressure abnormality determination A according to the present invention.
FIG. 5 is a time chart when a high-pressure abnormality (A) occurs according to the present invention.
FIG. 6 is a time chart showing a relationship between a detection signal and abnormal output when abnormal discharge occurs in a high voltage output.
7A is a block circuit diagram of a conventional high-voltage power supply unit according to the present invention; FIG.
FIG. 8 is a flowchart of a high-pressure abnormality determination B;
[Explanation of symbols]
201 CPU
202 High voltage power supply unit 202A High voltage controller 202B High voltage generator 202C Abnormality detection circuit 202D Latch circuit 203 ROM
204 Memory 205 Display unit

Claims (1)

If by detecting the output current other than the primary high-pressure supply is determined to be abnormal high pressure error output, it stops the output of the high-voltage power supply, the recording operation is stopped, an electrostatic recording apparatus of displaying a abnormal state in the high-pressure abnormality detecting method,
When the abnormality detection circuit detects the abnormality of the high voltage output,
An abnormal signal for stopping the output of the high-voltage power supply is input to the CPU via the latch circuit to stop the output of the high-voltage power supply,
While holding the output stop state of the high-voltage power supply by the latch circuit,
A high-pressure abnormality page counter that counts the high-pressure abnormality output that occurs once in one page is counted up,
Using the OFF control signal from the CPU for the high-voltage power supply to reset the latch circuit,
The high-voltage power supply is driven by turning on the control signal,
The timing of outputting the high voltage power supply is the timing when writing between recording pages is not performed,
By repeating the above operation, when the count value of the abnormal page counter becomes a value that has been set arbitrarily twice or more,
For the first time, the recording operation is interrupted and stopped by judging that the high-voltage power supply cannot be restored and the high-voltage output is abnormal,
Display an error display on the display,
If no abnormal output occurs during the period from the counting of the abnormal page counter to the set value, the abnormal page counter is cleared.
A method for detecting a high-pressure abnormality in an electrostatic recording device.

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