JPH1124375A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the cleaning function of a corona discharge wire, to improve the durability of the corona discharge wire and the cleaning member, to reduce the cleaning irregularity of the corona discharge wire, and to automatically decide the function degradation of the corona discharge wire. SOLUTION: Voltage is applied to the corona discharge wire 1 by using a constant current power source 11. The device is provide with means (10 and 60) for detecting the voltage applied to the corona discharge wire 1, and a cleaning controlling means 60. The device is provided with a cleaning member 3 composed of two kind of different members of the A-cleaning member 3a consisting of the elastic member and the B-cleaning member 3b consisting of abrasive compounds. When the variation width of the voltage exceeds the reference voltage variation width, the cleaning means 60 perform the cleaning of the corona discharge wire 1 by the B-cleaning member 3b by judging that the corona discharge wire is the deterioration, and at the periodical cleaning time of the corona discharge wire 1, the cleaning is performed by the A-cleaning member 3a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus provided with a corona discharge wire for charging an object to be charged such as an image carrier and a transfer material, and a cleaning member for cleaning the corona discharge wire.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic copying machine or a printer, a corona charging device is used as a charging device for performing uniform charging of the surface of an image carrier, transfer charging to a transfer material, or charge removal separation. Widely used. The corona charging device uses an electric charge generated by a corona discharge phenomenon caused by a strong electric field generated between a corona discharge wire to which a high voltage is applied and a shield electrode facing the discharge wire, and uses the image carrier and the transfer material. And the like to charge or remove electricity.

[0003] Since corona charging devices use high voltages,
A foreign substance such as dust, floating toner, or a product generated by corona discharge existing inside the image forming apparatus is electrostatically attracted and adheres to the corona discharge wire, casing, grid, etc. with the passage of time to prevent dirt and deterioration. Easy to invite. Further, even when a high voltage is not applied, fine particles (toner, dust, cigarette smoke, vehicle exhaust gas, etc.) in the air are likely to adhere. When the stain becomes severe, the discharge efficiency of the stained portion is reduced, or intensive local discharge is caused to cause uneven discharge. Various defects on the image, such as white stripes, black stripes, uneven recording density, and recording density Deterioration occurs.

In order to prevent this, conventionally, a cleaning pad is slid by pressing against a corona discharge wire or the like.
A method of wiping off attached matter with a cleaning pad has been proposed. As a cleaning member, an elastic material such as a felt or a sponge is generally used. However, although these cleaning members can remove ordinary deposits, they are insufficient for removing foreign matters firmly fixed to a corona discharge wire. For this reason, a cleaning member containing an abrasive may be used.

For example, in the cleaning device disclosed in Japanese Patent Application Laid-Open No. 2-118586, a cleaning member comprising a grinding material and felt members provided on both sides of the grinding material is fixed to each leg of an inverted U-shaped cleaning member holder. doing. The corona discharge wire is located at the center of the holder, that is, at a position sandwiched by these cleaning members. By moving the holder left and right along the corona discharge wire, the abrasive and the felt member slide against the corona discharge wire. To clean the wire surface. By adjusting the elasticity (deflection) of each leg of the inverted U-shaped cleaning member holder and the thickness of the cleaning member fixed thereto, the load applied by the abrasive to the corona discharge wire and the load applied by the felt member to the corona discharge wire Is adjusted to balance the polishing by the abrasive and the wiping by the felt member.

[0006]

However, in the cleaning device disclosed in Japanese Patent Application Laid-Open No. 2-118586, if the pressure of the cleaning member against the corona discharge wire is increased in order to improve the cleaning function, There have been problems such as the cleaning member itself being damaged by the corona discharge wire and cutting the corona discharge wire. On the other hand, although the cleaning member containing the abrasive has an excellent cleaning function, the polishing function is deteriorated with use, and the durability of the corona discharge wire itself is reduced because the corona discharge wire is shaved by the polishing member. there were.

A first object of the present invention is to improve the cleaning function of the corona discharge wire and to improve the durability of the corona discharge wire and the cleaning member, and to reduce the unevenness of cleaning of the corona discharge wire. The third object is to automatically determine the functional deterioration of the corona discharge wire.

[0008]

[Means for Solving the Problems]

(1) The present invention provides an image bearing member (101) or an image bearing member
(101) a corona discharge wire (1) for charging a transfer member for transferring an electrostatic latent image formed thereon, and the corona discharge wire (1)
Image forming apparatus, comprising: a cleaning member (3) for cleaning a corona discharge wire; and a constant current power supply (11) for applying a voltage to the corona discharge wire (1).
(100) A cleaning member (3a) rich in elasticity for cleaning the corona discharge wire (1) and B
Cleaning member (3b); applied voltage (Vc) to the corona discharge wire (1)
h) means (10, 60) for detecting the fluctuation width (ΔV ₁ ); and when the fluctuation width (ΔV ₁ ) exceeds a set value (ΔV ₀ ),
The corona discharge wire (1) is cleaned by a cleaning member (3b), and the periodic cleaning of the corona discharge wire (1) includes cleaning control means (60) performed by the A cleaning member (3a). Features.

To facilitate understanding, reference numerals in parentheses for corresponding elements or corresponding items in the embodiment shown in the drawings and described later are added for reference.

[0010] Corona discharge wire (1) deteriorates (dirt adheres)
As a result, the load impedance changes. However, the power supply of the corona discharge wire (1) is a constant current power supply (11),
The current value is constant, and the wire applied voltage value (Vch) changes.
Then, the detecting means (10, 60) detects the variation (ΔV
₁ ) is detected, and when it exceeds the set value (ΔV ₀ ), the cleaning control means (60) determines that the corona discharge wire (1) has deteriorated and the cleaning member B (3b) made of an abrasive material. ) To clean the corona discharge wire (1). Periodic cleaning of the corona discharge wire (1), which is performed when the above-described deterioration of the corona discharge wire (1) is not detected, is performed by an A cleaning member (3a) made of a member having a high elasticity. Hereinafter, this cleaning mode is referred to as "a-mode cleaning".

Thus, the detecting means (10, 60) and the cleaning control means
At step (60), the degree of contamination (deterioration) of the corona discharge wire (1) is detected, and two different cleaning members are used according to the degree of contamination.
Since an appropriate cleaning member is selected from (A cleaning member (3a) and B cleaning member (3b)), the cleaning function of the corona discharge wire (1) is improved, and the corona discharge wire (1) and the cleaning member (3) are selected. The durability of the A cleaning member (3a) and the B cleaning member (3b) is improved.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

(2) The cleaning control means (60) cleans the corona discharge wire (1) by the A cleaning member (3a) immediately after cleaning the corona discharge wire (1) by the B cleaning member (3b). .
Hereinafter, this cleaning mode is referred to as "b-mode cleaning".

When the foreign material on the corona discharge wire (1) is scraped off by the B cleaning member (3b) made of an abrasive, shavings may remain on the corona discharge wire (1), thereby causing discharge unevenness. there is a possibility. In the "cleaning in the b mode", the shavings are cleaned immediately after the cleaning by the B cleaning member (3b) by cleaning again with the A cleaning member (3a) made of a highly elastic member. The cleaning property of the corona discharge wire (1) is further improved.

(3) The cleaning control means (60) determines the fluctuation range of the applied voltage (Vch) of the corona discharge wire (1) after the cleaning of the corona discharge wire (1) by the B cleaning member (3b).
When (ΔV ₁ ) exceeds the set value (ΔV ₀ ), a display prompting replacement of the corona discharge wire (1) is performed. That is, the cleaning control means (60) automatically determines the functional deterioration of the corona discharge wire,
Displays the function deterioration.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0016]

FIG. 1 shows an outline of an electrophotographic laser printer 100 having a corona discharger according to the present invention. The photoconductor drum 21 is charged by a charging device (corona discharger) 102 including a discharge wire 1 and a cleaning member 3 (described later), and the like.
The exposure device 200 scans and projects the laser light modulated with the image data on the charged surface using a polygon mirror. Thus, the magnetic brush roller 104a of the developing unit 104 gives a toner to the electrostatic latent image formed on the photoreceptor surface.
As a result, the electrostatic latent image becomes a toner image (visible image). The potential sensor 111, the pre-transfer charger 110, and the pre-transfer lamp 112 control the printing process conditions.

Transfer charger (corona discharger) 105
Is an electrostatic latent image attached to the surface of the photosensitive drum 21 by applying a potential higher than the potential on the surface of the photosensitive drum 21 from the back surface of the transfer paper (recording paper) supplied by the registration roller 113. Is transferred (transferred) onto the transfer paper in accordance with the charge of the toner. The transfer sheet is charged with a charge suppressed by a separation charger 106, separated from the photosensitive drum 21 by a separation claw, and sent to a fixing unit (not shown) by a paper transport unit (not shown). The fixing device heats and presses the toner on the transfer paper and joins (fixes) it to the transfer paper.
I do. The transfer paper after fixing is discharged outside the machine.

The photosensitive drum 21 is not completely transferred onto the transfer paper.
The remaining toner adhering to the surface is scraped off by the cleaning brush 107a and the cleaning blade 107b of the cleaning unit 107. Photoconductor drum 2
One surface is neutralized by a neutralization lamp 108.

FIG. 2 shows an enlarged view of a main part of the corona discharger 102, and FIG. 3 shows the cleaning member 3 of the corona discharger 102 in a perspective view from the back. The corona discharger 102 includes a corona discharge wire 1 and shield plates 2a and 2b. A cleaning device for cleaning the corona discharge wire 1 includes a cleaning member 3, a cleaning member support member 4, a cleaning member support member 4, and a screw. It is composed of a lead screw 5 extending in the vertical direction. The cleaning member 3 includes an A cleaning member 3a made of an elastic member (elastic member) such as felt or sponge;
The cleaning member 3 is composed of two different members, namely, a B cleaning member 3b made of an abrasive, and the same member is disposed at an inner diagonal position of the cleaning member 3 having an inverted U-shaped cross section.
The cleaning member 3 is rotatably attached to the cleaning member support member 4. In addition, a shutter member 6 that is movable in the left-right direction (x direction) in FIG. 2 by a drive solenoid 7 is attached to the upper portion of the charging device.

When foreign matter adheres to the corona discharge wire 1, vibrations occur in the corona discharge wire 1 during corona discharge. In particular, this phenomenon is likely to occur when strong chemicals due to discharge products adhere. Then, the distance between the corona discharge wire 1 and the photosensitive drum 21 or the shield plates 2a and 2b is changed by the vibration. That is, the load impedance of the corona discharge wire 1 changes. Then, when the power supply is controlled with a constant current so that a constant current always flows like the constant current power supply 11, the applied voltage (detection voltage Vch) as shown in FIG.
Changes. Therefore, the degree of contamination (deterioration) of the corona discharge wire can be detected by detecting the change in the applied voltage.

In this embodiment, the voltage detection circuit 10 detects the applied voltage Vch, and the CPU 60
The voltage detection signal of 0 is digitally converted and read, and the upper peak value VchH and the lower peak value VchL of the applied voltage Vch are detected, and the fluctuation width ΔV ₁ = VchH−VchL of the applied voltage Vch is calculated. . The CPU 60 determines the variation width ΔV of the applied voltage Vch.
₁ is compared with a preset reference variation width (set value) ΔV _0, and if ΔV ₁ is equal to or larger than ΔV ₀ , the b-mode cleaning is performed when image formation is completed. Do. Next, a cleaning mode that can be performed by the cleaning member 3 will be described.

1. Cleaning with only B cleaning member 3b: FIG.
(FIG. 2 as viewed from below). Initially, the cleaning member 3 is at a home position in contact with the right corona discharge wire support member 12a in FIG. The drive motor 8 is rotated by a signal sent from the control circuit 9, and the lead screw is rotated.
Rotate 5 Thereby, the cleaning member 3 attached to the cleaning member support member 4 moves leftward (−y direction) from the home position in FIG. At this time, the shutter member 6, which is normally retracted to a position where it does not hit the projection 3c provided on the cleaning member 3, is
Move in x direction. Then, the shutter member 6 comes into contact with the projection 3c of the cleaning member 3, so that the cleaning member 3 rotates clockwise in FIG. 4 around the rotation shaft 3d of the cleaning member,
The B cleaning member 3b contacts the corona discharge wire 1. When the cleaning member 3 moves in the −y direction in that state, the corona discharge wire 1 is cleaned by the B cleaning member 3b.

When the projection 3c of the cleaning member 3 reaches further leftward from the left end of the shutter member 6, the cleaning member 3 rotates counterclockwise, and the B cleaning member 3b separates from the corona discharge wire 1. In this state, the cleaning member 3 contacts the left corona discharge wire support member 12b.

When the drive motor 8 is rotated in the reverse direction to move the cleaning member 3 from left to right and return to the home position,
The cleaning member 3 is moved by the drive solenoid 7 to the shutter member 6.
To the retracted position that does not hit the projection 3c. Therefore, on the double track, both the cleaning members A and B of the cleaning member 3 move to the home position while being separated from the corona discharge wire 1, and
The cleaning operation is completed. That is, the corona discharge wire 1 is cleaned only by the B cleaning member 3b made of an abrasive on the outward path.

2. Cleaning using only A cleaning member (cleaning in a mode): The periodic cleaning separately specified is performed by the CPU 60.
Is executed when the copy number N becomes equal to or more than the set value Ncc, and when the image formation is completed and the image formation start input is awaited.
Clear That is, the periodic cleaning is performed every time the image formation of Ncc or more is completed. In this regular cleaning, CPU
Reference numeral 60 moves the cleaning member 3 leftward from the home position in FIG. At that time, the shutter member 6
Is moved to a position where it does not hit the projection 3c of the cleaning member 3 so that the cleaning member 3 is moved.

When the cleaning member 3 reaches the position of the corona discharge wire support member 12b on the left side, the drive motor 8 rotates in the reverse direction and moves the cleaning member 3 to the right. At this time, the shutter member 6 is moved by the drive solenoid 7 to the protrusion 3c of the cleaning member 3.
4, the cleaning member 3 rotates counterclockwise in FIG. 4 around the rotation shaft 3 d of the cleaning member, and the A cleaning member 3 a contacts the corona discharge wire 1. In this state, the corona discharge wire 1 is cleaned by the A cleaning member 3a by moving the cleaning member 3 rightward (+ y direction).
When the protrusion 3c of the cleaning member 3 reaches further rightward from the right end of the shutter member 6, the cleaning member 3 rotates clockwise, and the A cleaning member 3a separates from the corona discharge wire 1 to complete the cleaning operation. In this state, the cleaning member 3 comes into contact with the corona discharge wire support member 12a and stops. That is, it returns to the home position. In this way, the corona discharge wire 1 is cleaned by the A cleaning member 3a made of an elastic member such as felt or sponge only on the return path.

3. b-mode cleaning: cleaning member 3
Moves from the right corona discharge wire support member 12a to the left corona discharge wire support member 12b.
This is the same operation as described above, and the corona discharge wire 1 is cleaned by the B cleaning member 3b made of an abrasive.

When the cleaning member 3 moves rightward (+ y direction) from the corona discharge wire support member 12b on the left side, the shutter member 6 is kept at a position where it contacts the projection 3c of the cleaning member 3. Then, when the protrusion 3c of the cleaning member 3 reaches the left end position of the shutter member 6, the cleaning member 3 rotates counterclockwise in FIG. 4 around the rotation shaft 3d of the cleaning member, and the A cleaning member 3a is moved by the corona discharge wire. Touch 1.
By moving the cleaning member 3 in this state, the corona discharge wire 1 is cleaned by the A cleaning member 3a made of an elastic member such as felt or sponge. When the protrusion 3c of the cleaning member 3 moves away from the right end of the shutter member 6, the cleaning member 3 rotates clockwise, and the A cleaning member 3a separates from the corona discharge wire 1 to complete the cleaning operation. In this state, the cleaning member 3 comes into contact with the corona discharge wire support member 12a and stops. That is, it returns to the home position. As described above, the corona discharge wire 1 is cleaned by the B cleaning member 3b made of an abrasive on the outward path, and the corona discharge wire 1 is cleaned by the A cleaning member 3a made of an elastic member such as felt or sponge on the return path.

This is because when the foreign material of the corona discharge wire 1 is scraped off with an abrasive such as the B cleaning member 3b, shavings may be left on the corona discharge wire 1, thereby causing discharge unevenness. Immediately thereafter, cleaning is performed again with an elastic member such as the A cleaning member 3a, thereby collecting shavings and obtaining better cleaning performance.

As the discharge time of the corona discharge wire 1 increases, dirt accumulates and the deterioration progresses. The life of the corona discharge wire 1 does not recover even after cleaning. Immediately after the cleaning by the B cleaning member 3b made of the abrasive, the CPU 60 again detects the variation width of the applied voltage by the voltage detection circuit 10 to be ΔV ₁ ,
Compares the reference fluctuation width [Delta] V ₀ set in advance as V _1, ΔV ₁
Is larger than ΔV ₀ , a display urging replacement of the corona discharge wire 1 is performed. As a result, when the corona discharge wire 1 is deteriorated, a display for automatically prompting replacement is generated.

FIG. 6 shows an outline of an electric system of the image forming apparatus 100 shown in FIGS. CPU60, RAM
61, a ROM 62, an EEPROM 67 (non-volatile memory), a control unit using a microcomputer composed of input / output port buffer amplifiers 63 and 64, and the like.
The ADF 80 (not shown) and the exposure apparatus 200 are controlled by serial communication between the 60 T × D, R × D, and PC2 terminals. The serial communication is configured such that when the output of the PC 2 is at the H level, the ADF 80 communicates with the control unit, and when the output of the PC 2 is at the L level, the exposure apparatus 200 communicates with the control unit. ing. Here, the microcomputer of the ADF 80 performs document feeding / discharging processing and jam detection based on data transmitted from the control unit of the copying machine. On the other hand, the microcomputer of the exposure apparatus 200 drives and controls the scanner and the mirror based on the data transmitted from the control unit. In addition,
In the CPU 60, a sheet sorting unit, a sheet reusing unit, a defective printing preventing unit, a conveyance resuming unit, and the like are formed by firmware or the like.

The drive motor 8 of the lead screw 5
In synchronization with the rotation of the pulse, the pulse generator 65 generates one pulse for each rotation of the minute angle, and the control unit here uses the pulse count value generated by the synchronization pulse generator 65 based on the count value of the pulse. At the position (home position) where the cleaning member 3 is in contact with the corona discharge wire 12a and the position where the cleaning member 3 is in contact with the corona discharge wire 12b, normal rotation, reverse power and stop processing are performed. The synchronizing pulse is generated by the pulse generator 65 in synchronism with the rotation of the drive motor 8, and
Give to PU60. The CPU 60 executes an interrupt process every time one pulse arrives, counts up the number of incoming pulses,
The count value is compared with the count value of the timing table (table storing the relationship between the count value and the event). If the count value matches one count value of the table, the count value is sent to the count value. Event (on / off of drive motor 8, reverse rotation).

FIG. 7 shows an outline of the control operation of the CPU 60. When the power is turned on, the CPU 60 sets an internal register,
A counter, a timer, and the like are set to the values in the standby state, and the input and output ports for the mechanism unit are set to the signal levels during the standby (step 1). Hereinafter, the word "step" is omitted in parentheses and only the step number is described.

When the initialization (1) is completed, the CPU 60 reads the state of the mechanism unit and checks for an abnormality (a state where image formation cannot be started) (2, 3). The information is displayed on the operation board 66 (not shown) (4). If there is no abnormality, energization of the heater of the fixing device is started, the target temperature is set to the standby value, warming up to the target temperature is started, and the fixing temperature (fixing device (not shown) (Fixing roller temperature) is at the standby temperature. If the temperature has not reached the standby temperature, wait until the temperature reaches the standby temperature. When the standby temperature is reached, Ready (image formation possible) is displayed on the operation display section, and when there is an operator operation on the operation board 66, it is read (5). Here, the input, such as the input of the number of recording sheets, the input of the recording magnification, the input of the recording density, etc., is written in the register. The register is an internal memory of the CPU 60 or a memory area allocated to the RAM 61 or the EEPROM 67.

If there is a start input, an operation key is displayed to that effect.
The CPU 60 updates the target temperature of the fixing unit to a high temperature for fixing processing (this causes the driver for controlling the fixing temperature to switch the current supplied to the fixing heater to a high level). The rotation drive of the photoconductor 21 and the lighting of the charge removing lamp (charge removing exposure) are started. The CPU 60 then sets the start and end timings of charging, exposure, erasing, paper feeding, development, transfer, etc. for one image formation (recording of one image) in the recording mode which has already been input. Corresponding to
The timing table is set, one copy cycle (one image forming process) is executed, and the recorded number counter (register) is counted up by one (9). During this one copy cycle (9), the CPU 60 executes the process control of charging (by the corona discharger 102), exposure, development and transfer. Here, 1 is added to the register N for counting the total number of copies (9a).

Next, it is checked whether the number of copies (the number of image formation: the number of continuous copies) has reached the set number (1).
0), when the set number has not been reached, one copy
Execute cycle (9). When the set number of sheets is reached, the target temperature of the fixing unit is returned to the standby value, and post-processing (end cycle) such as cleaning (continuation time) of the photoconductor, the transfer belt and the charging roller is set (end cycle) ( 11), operation board 6
Wait for an input at 6 (5). When there is no start input from the operation board 66 and the end cycle is completed, the rotation drive of the photoreceptor 21 is stopped, and the static elimination lamp is turned off.
Therefore, the end cycle is stopped (12, 13), and the processing shown in FIG. 8 is performed (to be described later).

FIG. 9 shows the "one copy cycle" shown in FIG.
In (9), the processing content of "voltage peak value detection" (RIV) executed by the CPU 60 at a constant period when the constant current power supply 11 shown in FIG. 2 is turned on is shown. Voltage detection circuit 1
0 detects the applied voltage Vch applied to the discharge wire 1, and the CPU 60 A / D converts and reads the voltage detection signal (31). If the value of the read applied voltage Vch is equal to or more than the value of the upper peak value register VchH (32), the value of the upper peak value register VchH is updated to the value of the read applied voltage Vch (33). ), Return. If the value of the read applied voltage Vch is equal to or less than the value of the upper peak value register VchH (32),
This time, the value is compared with the value of the lower peak value register VchL (3
4) If the applied voltage Vch is equal to or lower than the lower peak value register VchL, the value of the lower peak value register VchL is updated to the value of the applied voltage Vch and the process returns (35). When the read applied voltage Vch is larger than the value of the lower peak value register VchL, the return is performed as it is. The maximum value of the applied voltage Vch thus read is stored in the upper peak value register VchH, and the minimum value is stored in the lower peak value register VchL.
FIG. 8 shows the contents of the processing (-) after the end cycle (13) of FIG. By subtracting the value of the lower peak value register VchL from the upper peak value register VchH, the applied voltage V
The fluctuation width of ch is obtained and stored in the register ΔV ₁ (1
4). When the value of the register [Delta] V ₁ is less than or equal to the value of the reference fluctuation width [Delta] V ₀ is copied - the value of the register N for counting the number cumulative value is compared with a set value Ncc (16), if exceeded if a mode - de Periodic cleaning by (cleaning by A cleaning member) is performed (17), and the registers N, BmF, VchH, Vch
L is reset (18), and the process returns to the input reading of step 5 (FIG. 7). That is, the periodic cleaning is performed every time the image formation of the set value Ncc or more is completed. If not, the periodic cleaning is not performed, and the process returns to the input reading of step 5 (FIG. 7).

When the value of the variation width ΔV ₁ exceeds the value of the reference variation width ΔV ₀ , it is determined whether or not the register BmF is 1 (19). If it is not 1, the b-mode cleaning (B Immediately after cleaning by the cleaning member, cleaning by the A cleaning member
(20). That is, it is determined that the function of the corona discharge wire is reduced due to dirt, and b-mode cleaning is performed. Then, 1 is written into the register BmF (21), VchH and VchL are reset (22), and the process returns to the input reading of step 5 (FIG. 7). If the register BmF is 1 in the stap 19, that is, even though the b-mode cleaning has already been performed, the variation width ΔV of the applied voltage Vch
_{When 1} exceeds the value of the reference variation width ΔV ₀ , the operation board 6
In FIG. 6, "wire exchange required" is displayed (23), the registers N, BmF, VchH, and VchL are reset (24), and the process returns to the input reading of step 5 (FIG. 7). As described above, in the image forming apparatus of the present invention, the voltage fluctuation width detecting means 1
By detecting the fluctuation width ΔV ₁ of the applied voltage Vch of the constant current power supply 11 from 0 and 60, the degree of contamination of the corona discharge wire 1 is actually detected. When the fluctuation width ΔV ₁ exceeds a predetermined reference voltage fluctuation width ΔV ₀ , the corona discharge wire 1 is turned on by the B cleaning member 3b made of an abrasive and by the A cleaning member 3a made of an elastic member during regular cleaning.
Cleaning, it is possible to actually detect the degree of contamination of the corona discharge wire 1 and to select an appropriate cleaning member, thereby improving the cleaning function of the corona discharge wire 1 and improving the corona discharge wire 1 and the cleaning members 3a and 3a. 3b can be improved in durability.

By performing cleaning with the A cleaning member 3a immediately after cleaning with the B cleaning member 3b, the B cleaning member 3b is cleaned.
To prevent unevenness in cleaning, and more reliably improve the cleanability of the corona discharge wire 1.

Immediately after the cleaning by the B cleaning member 3b, the voltage fluctuation width ΔV ₁ is detected again, and the detection is made as the reference voltage fluctuation width ΔV _0.
Is exceeded, a message prompting replacement of the corona discharge wire 1 is displayed, so that the life (replacement time) of the corona discharge wire 1 can be appropriately determined.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing an outline of an electrophotographic laser printer including a corona discharger of the present invention.

FIG. 2 is a front sectional view schematically showing the corona discharger and the cleaning device of FIG.

FIG. 3 is a perspective view showing the cleaning member 3 from the back.

FIG. 4 is a rear view showing the corona discharger, the cleaning member, and the shutter member of FIG. 2 from below.

FIG. 5 is a graph showing a change in a power supply voltage applied to a corona discharge wire (1) vibrating under the influence of a foreign matter.

FIG. 6 is a block diagram showing an outline of an electric system of the laser printer shown in FIGS. 1 and 2;

FIG. 7 is a flowchart showing an outline of a control operation of a CPU 60 shown in FIG. 6;

8 is a flowchart showing the details of the processing of the remaining part (,) of FIG. 7;

FIG. 9 shows “voltage peak value detection” executed by CPU 60 at a constant period when constant current power supply 11 shown in FIG. 2 is turned on in “one copy cycle” (9) shown in FIG. "
This is a flowchart showing the contents of (RIV).

[Explanation of symbols]

 1: Discharge wire 2a, 2b: Shield plate 3: Cleaning member 3a: A cleaning member 3b: B cleaning member 3c: Projecting portion of cleaning member 3d: Rotating shaft of cleaning member 4: Cleaning member support member 5: Lead screw 6 : Shutter member 7: drive solenoid 8: drive motor 11: constant current power supply 12 a, 12 b: corona discharge wire support member 21: photosensitive drum 100: printer 101: photosensitive drum 102: charger (corona discharger) 103: exposure Slit 104: developing unit 104a: magnetic bronze roller 105: transfer charger 106: separation charger 107: cleaning unit 107a: fur brush 107b: cleaning blade 108: static elimination lamp 110: pre-transfer charger 111: potential sensor 112: pre-transfer lamp 113: resist roller 200: exposure apparatus

Claims (3)

[Claims] A corona discharge wire for charging an image carrier or a transfer member for transferring an electrostatic latent image formed on the image carrier; a cleaning member for cleaning the corona discharge wire; An image forming apparatus comprising: a constant current power supply for applying a voltage; and an elastic A for cleaning the corona discharge wire.
A B cleaning member comprising a cleaning member and an abrasive; a means for detecting a fluctuation range of the applied voltage of the corona discharge wire; and, when the fluctuation width exceeds a set value, the B cleaning member causes the corona discharge wire to rotate. An image forming apparatus comprising: a cleaning control unit that performs cleaning and performs periodic cleaning of the corona discharge wire by the A cleaning member. 2. The cleaning control means performs cleaning of the corona discharge wire by the A cleaning member immediately after cleaning of the corona discharge wire by the B cleaning member.
The image forming apparatus as described in the above. 3. The cleaning control means urges replacement of the corona discharge wire when the fluctuation range of the voltage applied to the corona discharge wire exceeds a set value after cleaning the corona discharge wire by the B cleaning member. The image forming apparatus according to claim 1, wherein the image is displayed.