JP2020166176A - Image forming apparatus - Google Patents

Abstract

To provide an image forming apparatus that can appropriately notify a user of the place of occurrence of abnormal discharge.SOLUTION: An image forming apparatus comprises: a photoreceptor; a charger that charges the photoreceptor; a detection unit that detects a charging voltage applied to the charger; and a control unit. The control unit executes abnormal discharge detection processing (S15) of detecting the occurrence of abnormal discharge based on the charging voltage detected by the detection unit, specification processing of specifying the charging voltage when the abnormal discharge is detected, first notification processing of notifying a user of cleaning of the charger when the charging voltage is equal to or larger than a predetermined threshold, and second notification processing (S17) of notifying the user of replacement or cleaning of a member different from the charger when the charging voltage is less than the predetermined threshold.SELECTED DRAWING: Figure 6

Description

The present invention relates to an image forming apparatus.

In an image forming apparatus such as a laser printer, abnormal discharge such as spark discharge or arc discharge may occur due to adhesion of toner or the like to the charging wire constituting the charger. Therefore, an image forming apparatus has been proposed that displays on the display unit that the user is prompted to clean the charged wire when an abnormal discharge is detected (see, for example, Patent Document 1). The image forming apparatus of Patent Document 1 is provided with a voltage detection circuit for detecting the wire voltage of the charging wire, and whether or not the charging wire is cleaned depends on whether or not the wire voltage detected by the voltage detection circuit is equal to or higher than a predetermined threshold value. To judge.

Japanese Unexamined Patent Publication No. 2019-12233

Here, in the image forming apparatus, abnormal discharge may occur even with a member different from the charging wire. However, the image forming apparatus of Patent Document 1 only determines whether or not the charging wire is cleaned, and does not determine anything regarding the cleaning of another member different from the charging wire. Therefore, when an abnormal discharge occurs in a member different from the charged wire, there is a problem that the user cannot clean the location where the abnormal discharge occurs and the abnormal discharge may reoccur.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an image forming apparatus capable of appropriately notifying a user of a location where an abnormal discharge has occurred.

In order to solve the above problems, the image forming apparatus according to one aspect of the present invention includes a photoconductor, a charger for charging the photoconductor, a charging voltage applied to the charging device, and the charging voltage. It includes a detection unit and a control unit that detect at least one of the charging current that flows through the charger when applied. The control unit performs an abnormal discharge detection process for detecting the occurrence of an abnormal discharge based on at least one of the charging voltage and the charging current detected by the detection unit, and the abnormal discharge when the abnormal discharge is detected. When at least one of the charging voltage and the charging current is specified and at least one of the charging voltage and the charging current when the abnormal discharge is detected is equal to or higher than a predetermined threshold value, the charging device is used. A member different from the charger when at least one of the charging voltage and the charging current when the abnormal discharge is detected is less than a predetermined threshold, and the first notification process for notifying the user of the cleaning. It is characterized by performing a second notification process for notifying the user of replacement or cleaning, and a notification process for executing.

According to the image forming apparatus having the above configuration, when at least one of the charging voltage and the charging current detected by the detection unit is equal to or higher than a predetermined threshold value, the user is required to clean the charger, which is the location where the abnormal discharge occurs. You can notify. Further, when at least one of the charging voltage and the charging current detected by the detection unit is less than a predetermined threshold value, the user can be notified of replacement or cleaning of a member different from the charger. In this way, it is possible to appropriately notify the user of the location where the abnormal discharge occurs. As a result, the user can prevent the recurrence of the abnormal discharge by replacing or cleaning the member at the location where the abnormal discharge occurs.

Further, in the image forming apparatus according to one aspect of the present invention, the control unit executes a process of notifying the user that the photoconductor is removed from the image forming apparatus in the second notification process. Then, after the photoconductor is removed from the image forming apparatus, in a state where a charging voltage is applied to the charger, the control unit (i) replaces or cleans the photoconductor if it does not detect the occurrence of abnormal discharge. If the process of notifying the user is executed and (ii) the occurrence of abnormal discharge is detected, the process of notifying the user of replacement or cleaning of another member other than the charger and the photoconductor may be executed.

According to the image forming apparatus having the above-described configuration, if the control unit does not detect the occurrence of abnormal discharge by removing the photoconductor from the image forming apparatus, the user knows that the photoconductor has generated abnormal discharge. Can be notified to. Further, even if the photoconductor is removed from the image forming apparatus, if the control unit detects the occurrence of abnormal discharge, the user can be notified that the charger and another member other than the photoconductor should be replaced or cleaned. In this way, even when an abnormal discharge occurs in a member other than the charger, the user can be appropriately notified of the location where the abnormal discharge occurs.

Further, in the image forming apparatus according to one aspect of the present invention, the separate member includes a first separate member and a second separate member. In the second notification process, the control unit executes a process of notifying the user of the removal of the first separate member. Then, after the first separate member is removed from the image forming apparatus while leaving the photoconductor, in a state where a charging voltage is applied to the charger, the control unit must (i) detect the occurrence of abnormal discharge. The process of notifying the user of the replacement or cleaning of the first separate member is executed, and (ii) the process of notifying the user that the photoconductor is removed from the image forming apparatus when the occurrence of abnormal discharge is detected is executed. Then, the control unit replaces or cleans the photoconductor if (a) the occurrence of abnormal discharge is not detected in a state where the charging voltage is applied to the charger after the photoconductor is removed from the image forming apparatus. If (b) the occurrence of an abnormal discharge is detected, the process of notifying the user of the replacement or cleaning of the second separate member may be executed.

According to the image forming apparatus having the above-described configuration, after the first separate member is removed from the image forming apparatus while leaving the photoconductor, an abnormal discharge is generated by the control unit in a state where a charging voltage is applied to the charger. If it is not detected, it can be determined that an abnormal discharge has occurred in the first separate member, and replacement or cleaning of the first separate member can be notified. Further, if the occurrence of abnormal discharge is not detected in the state where the charging voltage is applied to the charger after the photoconductor is removed from the image forming apparatus, it is determined that the photoconductor has undergone abnormal discharge, and the photoconductor is determined to have generated abnormal discharge. Can be notified of replacement or cleaning. On the other hand, if the occurrence of abnormal discharge is detected, it can be determined that abnormal discharge has occurred in the second separate member, and replacement or cleaning of the second separate member can be notified.

Further, in the image forming apparatus according to one aspect of the present invention, the first separate member may be a transport belt for transporting recording paper.

According to the image forming apparatus having the above configuration, it is possible to detect the occurrence of abnormal discharge due to the adhesion of toner or the like to the transport belt, and notify the user of the cleaning or replacement of the transport belt.

Further, in the image forming apparatus according to one aspect of the present invention, the second separate member may be provided at a position corresponding to the power transmission wire connecting the charger and the ground.

According to the image forming apparatus having the above configuration, the occurrence of abnormal discharge in the power transmission wire connecting the charger and the ground can be detected, and the recurrence of abnormal discharge can be prevented by cleaning or replacing the member in the corresponding place. it can.

Further, the image forming apparatus according to one aspect of the present invention includes a fan for discharging the air inside the image forming apparatus. The second separate member may be a protective member that protects the deposit from adhering to the power transmission wire by the fan.

According to the image forming apparatus having the above-described configuration, it is possible to detect that an abnormal discharge has occurred in the protective member due to the deposits adhering to the protective member, and to notify the user of cleaning or replacement of the protective member.

Further, the image forming apparatus according to one aspect of the present invention includes a charging voltage applying unit that applies a charging voltage to each of a plurality of charging devices. A plurality of photoconductors are provided. The charger is provided at a position corresponding to the plurality of photoconductors. The charging voltage application unit applies a charging voltage to each of the plurality of charging devices in order. The detection unit detects at least one of the charging voltage of each of the plurality of charging devices and the charging current flowing through each of the plurality of charging devices by applying the charging voltage. The control unit detects the occurrence of abnormal discharge at a location corresponding to each charger based on at least one of the charging voltage of each of the plurality of chargers detected by the detection unit and the charging current of each of the plurality of chargers. Then, the user may be notified of the replacement or cleaning of the member at the location corresponding to each charger.

According to the image forming apparatus having the above-described configuration, the control unit detects at least one of the charging voltage and the charging current of the plurality of charging devices at the location corresponding to each charging device. The occurrence of abnormal discharge can be detected, and the user can be notified of replacement or cleaning of a member at a location corresponding to each charger.

Further, in the image forming apparatus according to one aspect of the present invention, the charger has at least a charging wire. The detection unit may detect at least one of the charging voltage of the charging wire and the charging current of the charging wire.

According to the image forming apparatus having the above configuration, the control unit can detect the occurrence of abnormal discharge based on at least one of the charging voltage of the charging wire detected by the detection unit and the charging current of the charging wire. Therefore, it is possible to ensure redundancy for detecting the occurrence of abnormal discharge.

According to the image forming apparatus of the present invention, it is possible to appropriately notify the user of the location where the abnormal discharge occurs.

It is sectional drawing which shows the schematic structure of the image forming apparatus which concerns on Embodiment 1 of this invention. It is a block diagram of the image forming apparatus which concerns on Embodiment 1. FIG. It is the schematic which shows the detection method of the abnormal discharge of the image forming apparatus which concerns on Embodiment 1. FIG. It is a peripheral view of the protective film of the image forming apparatus which concerns on Embodiment 1. FIG. It is a flowchart which shows the flow of the abnormal discharge detection processing of the image forming apparatus which concerns on Embodiment 1. It is a flowchart which shows the flow of the abnormal discharge part identification processing which concerns on Embodiment 1 (the 1). It is a flowchart which shows the flow of the abnormal discharge part identification processing which concerns on Embodiment 1 (the 2). It is a flowchart which shows the flow of the abnormal discharge part identification processing which concerns on Embodiment 1 (the 3). It is a flowchart which shows the flow of the abnormal discharge detection processing of the image forming apparatus which concerns on Embodiment 2 of this invention. It is a flowchart which shows the flow of the abnormal discharge part identification processing of the image forming apparatus which concerns on Embodiment 2.

[Embodiment 1]
Hereinafter, the image forming apparatus according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 8.
[Outline configuration of image forming apparatus]
FIG. 1 is a cross-sectional view showing a schematic configuration of the image forming apparatus 1 according to the first embodiment. The image forming apparatus 1 of the first embodiment is a color laser printer that forms a color image on recording paper P or the like by the Carlson method. As shown in FIG. 1, the image forming apparatus 1 has a box-shaped apparatus main body 2, and a paper feeding unit 10 and an image forming unit 20 are housed inside the apparatus main body 2. In the following description, the right side of FIG. 1 is the front side of the image forming apparatus 1, the left side of FIG. 1 is the rear surface side of the image forming apparatus 1, the upper side of FIG. 1 is the upper side of the image forming apparatus 1, and the lower side of FIG. 1 is an image. It is the lower side of the forming device 1. Further, the front side of the paper surface of FIG. 1 is the left side when viewed from the front side of the image forming apparatus 1, and the back side of the paper surface of FIG. 1 is the right side.

The device main body 2 has a housing 3 that opens upward, and a cover 7 that is rotatably connected to the housing 3 via a hinge portion 4 so as to close the opening of the housing 3. A cover switch 70 for detecting the open / closed state of the cover 7 is attached to the inner wall of the housing 3. An discharge tray 5 is provided on the upper surface of the apparatus main body 2 to discharge the recording paper P on which the image is formed in a stacked state.

A display unit 8 is provided on the upper portion on the rear side of the cover 7. The display unit 8 has a display screen, an operation unit, and the like. A message or the like to be notified to the user is displayed on the display unit 8.

The image forming unit 20 includes a transport unit 21, four process cartridges 30Y, 30M, 30C, and 30K, an exposure unit 35, and a fixing unit 50. The transfer unit 21 is provided between the paper feed unit 10 and the process cartridge 30C, and has a transfer belt 23 and four transfer rollers 25Y, 25M, 25C, 25K and the like.

The transport belt 23 is an endless belt formed by forming an annular belt, and is wound around a drive roller 27 located below the rear end side of the image forming portion 20 and a driven roller 28 located below the front end side. The upper surface of the transport belt 23 extends substantially horizontally directly under the process cartridge 30C and the like, and comes into contact with the back surface of the recording paper P supplied from the paper feed unit 10. The drive roller 27 rotates the transport belt 23 in a predetermined direction. Further, the transport belt 23 is negatively charged by applying a transfer voltage to each of the transfer rollers 25Y, 25M, 25C, and 25K, and the recording paper P is adsorbed on the upper surface by electrostatic force while adsorbing the adsorbed recording paper P. Along the transport path R, the paper is transported from the right side to the left side of FIG. 1 toward the discharge tray 5.

In the transport path R of the recording paper P, four process cartridges 30Y and 30M corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (K) are arranged in order from the upstream side in the transport direction. , 30C, 30K are arranged. Each process cartridge 30Y, 30M, 30C, 30K is provided with four toner cartridges 33 corresponding to each color. The four toner cartridges 33 contain toners of corresponding colors. The arrangement order of the process cartridges 30Y, 30M, 30C, and 30K is not limited to this, and can be changed as appropriate.

Each process cartridge 30Y, 30M, 30C, 30K is provided with a photoconductor drum 31Y, 31M, 31C, 31K, which is a drum-shaped photoconductor, respectively. The photoconductor drums 31Y, 31M, 31C, and 31K are provided so as to face the transfer rollers 25Y, 25M, 25C, and 25K. Grounded drum shafts 32Y, 32M, 32C, 32K are provided at the axes of the photoconductor drums 31Y, 31M, 31C, and 31K.

Further, each process cartridge 30Y, 30M, 30C, 30K is provided with four chargers 40, respectively. Each charger 40 is, for example, a scorotron type corona charger in which the charging wire 41 and the grid 42 are housed in the casing 43. The charging wire 41 is made of a metal, for example, gold-plated tungsten or tungsten alone. A charging voltage is applied to the charging wire 41 from the charging voltage application unit 64.

An opening is formed in a portion of the casing 43 facing the photoconductor drums 31Y, 31M, 31C, and 31K. The grid 42 has a structure in which conductive wires are stretched in a mesh shape at the opening of the casing 43. The charger 40 is not limited to the scorotron type, and may be a corotron type without the grid 42.

Each charger 40 uniformly positively charges the surfaces of the corresponding photoconductor drums 31Y, 31M, 31C, and 31K at the time of image formation. Specifically, by applying a voltage to the charging wire 41 of each charging device 40, between each charging wire 41 and each photoconductor drum 31Y, 31M, 31C, 31K corresponding to each charging wire 41. , An electric field is formed and a corona discharge is generated.

The exposure unit 35 is provided at the uppermost part of the inside of the apparatus main body 2, and forms an electrostatic latent image based on image data on the surfaces of the charged photoconductor drums 31Y, 31M, 31C, and 31K. The toner cartridge 33 supplies toner to the surfaces of the photoconductor drums 31Y, 31M, 31C, and 31K by supporting the toner on the surface of the developing roller 47.

The developing roller 47 rotates while being supplied with the developing voltage, so that the toner in the toner cartridge 33 is triboelectrically charged by the friction accompanying the rotation and supplied to the surfaces of the photoconductor drums 31Y, 31M, 31C, and 31K. .. In the photoconductor drums 31Y, 31M, 31C, and 31K, a toner image is formed by supplying toner to the electrostatic latent image formed on the surface.

The transport unit 21 transports the recording paper P toward the fixing unit 50. The recording paper P is conveyed while being sandwiched between the transfer rollers 25Y, 25M, 25C, 25K to which the transfer voltage is applied and the photoconductor drums 31Y, 31M, 31C, 31K. The developed toner image is transferred to the surfaces of the drums 31Y, 31M, 31C, and 31K.

The fixing portion 50 is provided on the downstream side of the transport path R with respect to the transport unit 21. The fixing portion 50 has a heating roller 51 and a pressurizing roller 52. The heating roller 51 is arranged on the image forming surface side of the recording paper P, rotates in synchronization with the transport belt 23 and the like, and conveys the recording paper P while heating the toner transferred to the recording paper P. The pressurizing roller 52 sandwiches the recording paper P with the heating roller 51 and rotates drivenly while pressing the recording paper P toward the heating roller 51. As a result, the fixing unit 50 heats and melts the toner transferred to the recording paper P and fixes it on the recording paper P. The recording paper P on which the toner is fixed by the fixing unit 50 is conveyed along the conveying path R and discharged to the discharge tray 5.

The paper feed unit 10 has a paper feed tray 11 in which the recording paper P is housed and various rollers, and drives the various rollers to feed the recording paper P to the image forming unit 20. Further, the paper feed tray 11 is configured to be detachable from the lower part of the device main body 2.

Further, as shown in FIG. 1, the apparatus main body 2 is provided with a cooling fan 9. The fan 9 rotates by obtaining a driving force from the motor 90, and discharges the air inside the image forming apparatus 1 to the outside of the apparatus main body 2. Although not shown, the periphery of each charger 40 is connected by a duct as an air flow path of the fan 9.

Further, as shown in FIG. 4, a replaceable protective film 91 is provided in the vicinity of each fan 9. The protective film 91 is a protective member that protects deposits such as toner from adhering to the power transmission wire 40Y due to the flow of air by the fan 9. The protective film 91 is arranged so as to cover the spring 44 connected to the power transmission wire 40Y connecting each charger 40 and the ground. Since the spring 44 is arranged in the middle between the charger 40 to which a high voltage is applied and the ground, an abnormal discharge is likely to occur. If deposits adhere to the protective film 91 and an abnormal discharge occurs, the protective film 91 is cleaned or replaced.

[Electrical configuration of image forming apparatus]
FIG. 2 is a block diagram of the image forming apparatus 1. As shown in FIG. 2, the control unit 6 includes a paper feed unit 10, an image forming unit 20, a power switch 67, a cover switch 70, a motor 90, a display unit 8, a charging voltage applying unit 64, a voltage detecting unit 65, and a current detection unit. It is electrically connected to the unit 66. At least one of the voltage detection unit 65 and the current detection unit 66 is an example of the detection unit.

The control unit 6 performs general control on each unit of the image forming apparatus 1. The control unit 6 includes a CPU (Central Processing Unit) 61, a ROM (Read Only Memory) 62, a RAM (Random Access Memory) 63, and the like. The ROM 62 stores various control programs, various settings, and the like for controlling the image forming apparatus 1. The RAM 63 is used as a work area for reading various control programs and a storage area for temporarily storing image data. The control unit 6 controls the paper feeding unit 10, the image forming unit 20, and the like based on the control program read from the ROM 62. An application specific integrated circuit (ASIC) may be used instead of the CPU 61.

When the power switch 67 is turned on, an on signal is output to the control unit 6. The cover switch 70 outputs a signal corresponding to the opening / closing of the cover 7 to the control unit 6. For example, when the cover 7 is closed, the cover switch 70 outputs an on signal to the control unit 6, and when the cover 7 is open, the cover switch 70 outputs an on signal to the control unit 6. The fan 9 rotates when the motor 90 is driven and controlled by the control unit 6.

The charging voltage application unit 64 has a step-up transformer, a smoothing rectifier circuit, and the like, and applies a charging voltage to the charging wire 41 of each charging device 40. The voltage detection unit 65 detects the charge voltage value applied to the charger 40 from the charge voltage application unit 64. The current detection unit 66 detects the value of the charging current flowing through the charging wire 41 of the charging device 40 by applying the charging voltage. The charging voltage application unit 64 has a current control circuit (not shown). The current control circuit controls PWM (Pulse Width Modulation) to control the charging voltage value applied from the charging voltage applying unit 64 to the charging device 40 so that the charging current detected by the current detecting unit 66 becomes constant. To do.

FIG. 3 is a schematic view showing a method of detecting an abnormal discharge of the image forming apparatus 1. Note that FIG. 3 illustrates one of the four chargers 40 and the four photoconductor drums 31Y, 31M, 31C, and 31K for convenience of explanation.

As shown in FIG. 3, when a predetermined voltage, for example, about 5 to 6 [kV], is applied to the charging wire 41 of the charging device 40 by the charging voltage applying unit 64, the drum shaft is passed through the grid 42. Corona discharge occurs toward 32Y, 32M, 32C, and 32K. As a result, the surfaces of the photoconductor drums 31Y, 31M, 31C, and 31K are uniformly charged.

The voltage detection unit 65 is composed of, for example, a voltage dividing resistor, divides the charging voltage applied to the charging wire 41 of the charging device 40, and outputs a signal corresponding to the charging voltage value to the CPU 61 of the control unit 6. Further, the current detection unit 66 outputs a signal corresponding to the charging current value flowing through the charging wire 41 of the charging device 40 to the CPU 61 of the control unit 6 by applying the charging voltage. Specifically, the current detection unit 66 is composed of, for example, a resistor connected between the charging voltage application unit 64 and the power supply voltage (not shown), and generates a signal corresponding to the charging current value. The signal is output to the CPU 61.

The control unit 6 is an example of a control unit that realizes an abnormal discharge detection process, a specific process, and a notification process including a first notification process and a second notification process. The image forming apparatus 1 of the first embodiment detects the occurrence of abnormal discharge based on the charged voltage value detected by the voltage detecting unit 65. The abnormal discharge is different from, for example, a corona discharge, and refers to a spark discharge or an arc discharge caused by dirt on the charger 40 or the photoconductor drums 31Y, 31M, 31C, 31K due to toner or paper dust.

[Flow of abnormal discharge detection processing]
FIG. 5 is a flowchart showing the flow of the abnormal discharge detection process of the image forming apparatus 1 according to the first embodiment. The flowchart shown in FIG. 5 is an example, and the present invention is not limited to this.

When the power switch 67 is turned on and the cover 7 is closed (S1), the control unit 6 applies a charging voltage to each of the chargers 40 of 1ch to 4ch by outputting a control signal to the charging voltage application unit 64. (S2). Here, "1ch" is charging the charger 40 at the position corresponding to the photoconductor drum 31Y, "2ch" is charging the charger 40 at the position corresponding to the photoconductor drum 31M, and "3ch" is photosensitive. “4ch” means charging the charger 40 at the position corresponding to the body drum 31C, and “4ch” means charging the charging device 40 at the position corresponding to the photoconductor drum 31K.

Subsequently, the control unit 6 executes an abnormal discharge detection process for determining whether or not an abnormal discharge is detected at any of the 1ch to 4ch based on the charging voltage detected by the voltage detecting unit 65. (S3). The control unit 6 specifies the charging voltage when an abnormal discharge is detected at any of 1ch to 4ch (S3: YES) and when an abnormal discharge of any of 1ch to 4ch is detected. The process is performed to determine whether or not the charging voltage of any of 1ch to 4ch is equal to or higher than a predetermined threshold value (S4). The predetermined threshold value is, for example, about 6.6 [kV]. The threshold value can be appropriately changed according to the design conditions such as the charging voltage applied to the charger 40 at normal times.

When the control unit 6 determines that the charging voltage of any of 1ch to 4ch is equal to or higher than a predetermined threshold value (S4: YES), the control unit 6 notifies the cleaning of the charger 40 whose charging voltage exceeds the predetermined threshold value. 1 Execute the notification process (S5). Specifically, the control unit 6 causes the display unit 8 to indicate that the charger 40 whose charging voltage has reached the threshold value or higher should be cleaned. On the other hand, when all the charging voltages of channels 1 to 4 are less than a predetermined threshold value (S4: NO), the control unit 6 performs the abnormal discharge location identification process shown in FIG. 6 (S6).

FIG. 6 is a flowchart showing the flow of the abnormal discharge location identification process of the image forming apparatus 1 in the first embodiment. The flowchart shown in FIG. 6 is an example, and the present invention is not limited to this. In identifying the abnormal discharge location shown in FIG. 6, first, the control unit 6 notifies the user that the transport belt 23 is removed and the cover 7 is closed, leaving the photoconductor drums 31Y, 31M, 31C, and 31K (S11). .. Specifically, the control unit 6 causes the display unit 8 to indicate that the transport belt 23 is removed and the cover 7 is closed. When the user confirms the display on the display unit 8, the user opens the cover 7, removes the transport belt 23 from the image forming apparatus 1, and then closes the cover 7. In the first embodiment, the transport belt 23 is given as an example of the first separate member.

Next, the control unit 6 determines whether or not there is a transport belt 23 (S12). In this case, a sensor for detecting the presence / absence of the transport belt 23 is provided, and the control unit 6 determines whether or not the transport belt 23 is present based on the output signal of this sensor.

If there is a transport belt 23 (S12: YES), the process returns to S11, and if there is no transport belt 23 (S12: NO), the control unit 6 determines whether or not the photoconductor drums 31Y, 31M, 31C, and 31K are present. (S13). In this case, sensors for detecting the presence / absence of the photoconductor drums 31Y, 31M, 31C, and 31K are provided, and the control unit 6 controls the photoconductor drums 31Y, 31M, and 31C based on the output signals of these sensors. , 31K is determined.

If all the photoconductor drums 31Y, 31M, 31C, and 31K are not present (S13: NO), the process proceeds to S21 in FIG. On the other hand, when there are the photoconductor drums 31Y, 31M, 31C, and 31K (S13: YES), the control unit 6 outputs a control signal to the charging voltage application unit 64, so that the 1ch to 4ch chargers 40 are sequentially charged. A charging voltage is applied (S14). Then, the control unit 6 determines whether or not an abnormal discharge is detected in any of the chargers 40 of 1ch to 4ch based on the charging voltage detected by the voltage detecting unit 65 (S15).

When an abnormal discharge is detected in any of the chargers 40 of channels 1 to 4 (S16: YES), the control unit 6 notifies the user of the abnormally discharged channel (S16), and proceeds to S31 of FIG. Specifically, the control unit 6 causes the display unit 8 to display the abnormally discharged ch. On the other hand, when the abnormal discharge is not detected in all the chargers 40 of 1ch to 4ch (S15: NO), it is determined that the abnormal discharge has occurred in the transport belt 23, and the second notification process for notifying the replacement of the transport belt 23 is performed. (S17), the abnormal discharge location identification process is completed.

Next, moving to FIG. 7, the control unit 6 notifies the user whether the abnormal discharge location identification process can proceed as it is without the photoconductor drums 31Y, 31M, 31C, 31K and the transport belt 23 (S21). ). Specifically, the control unit 6 causes the display unit 8 to indicate to the user whether or not the abnormal discharge location identification process can proceed as it is. Then, the control unit 6 determines whether or not the charging voltage may be applied (S22). Specifically, when the user selects that the abnormal discharge location identification process may proceed, the control unit 6 determines that a charging voltage may be applied (S22: YES), and proceeds to S33 in FIG. On the other hand, if the user selects not to proceed with the abnormal discharge location identification process, the control unit 6 determines that the charging voltage is not applied to the chargers 40 of channels 1 to 4 (S22: YES), and proceeds to S11 of FIG. ..

Next, moving to FIG. 8, the control unit 6 notifies that the photoconductor drums 31Y, 31M, 31C, and 31K are removed and the cover 7 is closed (S31). Specifically, the control unit 6 removes the photoconductor drums 31Y, 31M, 31C, and 31K from the image forming apparatus 1, and causes the display unit 8 to indicate that the cover 7 is closed.

Then, after the user removes the photoconductor drums 31Y, 31M, 31C, 31K from the image forming apparatus 1 and closes the cover 7, the control unit 6 determines whether or not the photoconductor drums 31Y, 31M, 31C, 31K are present. Judgment (S32). When there are photoconductor drums 31Y, 31M, 31C, 31K (S32: YES), the process returns to S31, and when there is no photoconductor drum 31Y, 31M, 31C, 31K (S32: NO), the control unit 6 applies a charging voltage. By outputting the control signal to the unit 64, the charging voltage is sequentially applied to the charging devices 40 of 1ch to 4ch (S33).

Then, the control unit 6 executes an abnormal discharge detection process for determining whether or not an abnormal discharge is detected in any of the chargers 40 of channels 1 to 4 (S34). When an abnormal discharge is detected in any of the chargers 40 of channels 1 to 4 (S34: YES), the control unit 6 notifies the user of the channel in which the abnormal discharge is detected (S35), and the protective film for that channel. A second notification process for notifying the cleaning of 91 is performed (S36). On the other hand, when abnormal discharge is not detected in all the chargers 40 of 1ch to 4ch (S34: NO), the control unit 6 performs a second notification process for notifying the replacement of the photoconductor drums 31Y, 31M, 31C, 31K. (S37), the abnormal discharge location identification process is completed. In the first embodiment, the protective film 91 is given as an example of the second separate member.

In the image forming apparatus 1 of the first embodiment described above, when the charging voltage of the charging wire 41 of the charging device 40 detected by the voltage detecting unit 65 is equal to or higher than a predetermined threshold value, an abnormal discharge occurs in the charging device 40. It is possible to notify the user of the cleaning of the charger 40 by determining that the occurrence has occurred. In particular, since it is possible to detect in which of the chargers 40 of 1ch to 4ch the abnormal discharge has occurred, it is possible to appropriately notify the user of the cleaning of the charger 40 in which the abnormal discharge has occurred (S5).

Further, when the charging voltage of the charging wire 41 detected by the voltage detecting unit 65 is less than a predetermined threshold value, the user can be notified of replacement or cleaning of a member different from the charging device 40. Specifically, if the occurrence of abnormal discharge is not detected due to the transfer belt 23 being removed from the image forming apparatus 1 leaving the photoconductor drums 31Y, 31M, 31C, and 31K, the transfer belt 23 is abnormal. It is possible to determine that the discharge has occurred and notify the replacement of the transport belt 23 (S17).

Further, if the occurrence of abnormal discharge is not detected in the state where the charging voltage is applied to the charger 40 after the photoconductor drums 31Y, 31M, 31C, 31K are removed from the image forming apparatus 1, the photoconductor drum 31Y, It is possible to determine that an abnormal discharge has occurred in 31M, 31C, 31K and notify the replacement of the photoconductor drums 31Y, 31M, 31C, 31K (S37). On the other hand, if the occurrence of abnormal discharge is detected, it can be determined that the protective film 91 has generated abnormal discharge, and the cleaning of the protective film 91 can be notified (S36). In particular, since it is possible to detect which of the protective films 91 of 1ch to 4ch the abnormal discharge has occurred (S35), it is possible to appropriately notify the user of the cleaning of the protective film 91.

As described above, according to the image forming apparatus 1 of the first embodiment, the user can be appropriately notified of the location where the abnormal discharge occurs. As a result, the user can prevent the recurrence of the abnormal discharge by replacing or cleaning the member at the location where the abnormal discharge occurs.

[Embodiment 2]
Next, the image forming apparatus according to the second embodiment of the present invention will be described with reference to FIGS. 9 and 10. For convenience of explanation, the same reference numerals will be added to the members having the same functions as the members described in the first embodiment, and the description will not be repeated. The image forming apparatus 1 of the second embodiment is different from the first embodiment in that it is a monochrome laser printer.

Since the image forming apparatus 1 of the second embodiment is a monochrome laser printer, although not shown, the image forming unit 20 includes one process cartridge 30K, one photoconductor drum 31K, and one transfer roller 25K. One charger 40 is provided. Further, the transport belt 23 is not provided. In the second embodiment, it is assumed that the recording paper P is conveyed by the plurality of transfer rollers, the transfer roller 25K, and the photoconductor drum 31K.

[Flow of printing operation]
FIG. 9 is a flowchart showing the flow of the abnormal discharge detection process of the image forming apparatus 1 according to the second embodiment. The flowchart shown in FIG. 9 is an example, and the present invention is not limited to this.

When the power switch 67 is turned on and the cover 7 is closed (S41), the control unit 6 applies a charging voltage to the charging device 40 by outputting a control signal to the charging voltage applying unit 64 shown in FIG. 3 (S41). S42).

Subsequently, the control unit 6 executes an abnormal discharge detection process for detecting whether or not an abnormal discharge has occurred based on the charging voltage of the charging wire 41 of the charging device 40 detected by the voltage detecting unit 65 (S43). ). When an abnormal discharge is detected (S43: YES), the control unit 6 performs a specific process for specifying the charging voltage of the charging wire 41 when the abnormal discharge is detected, and the charging voltage is set to a predetermined threshold value, for example, 6. It is determined whether or not it is 6.6 [about kV] or more (S44).

When the control unit 6 determines that the charging voltage is equal to or higher than a predetermined threshold value (S44: YES), the control unit 6 executes a first notification process for notifying the cleaning of the charging device 40 (S45). Specifically, the control unit 6 causes the display unit 8 to indicate that the charger 40 that charges the photoconductor drum 31K should be cleaned. On the other hand, when the charging voltage is less than a predetermined threshold value (S44: NO), the process proceeds to the abnormal discharge location identification process shown in FIG. 10 (S46).

FIG. 10 is a flowchart showing the flow of the abnormal discharge location identification process of the image forming apparatus 1 in the second embodiment. The flowchart shown in FIG. 10 is an example, and the present invention is not limited to this.

In identifying the abnormal discharge location, first, the control unit 6 notifies the user that the photoconductor drum 31K is removed and the cover 7 is closed (S51). Specifically, the control unit 6 removes the photoconductor drum 31K and causes the display unit 8 to indicate that the cover 7 is closed. The user confirms the display of the display unit 8, opens the cover 7, removes the photoconductor drum 31K from the image forming apparatus 1, and then closes the cover 7.

Next, the control unit 6 determines whether or not there is a photoconductor drum 31K (S52). Specifically, the control unit 6 determines whether or not there is a photoconductor drum 31K based on a signal from a sensor that outputs a signal according to the presence or absence of the photoconductor drum 31K. If there is a photoconductor drum 31K (S52: YES), the process returns to S51, and if there is no photoconductor drum 31K (S52: NO), the control unit 6 has a charging voltage value detected by the voltage detection unit 65. Based on the above, an abnormal discharge detection process for determining whether or not an abnormal discharge has been detected is executed (S53).

When the abnormal discharge is detected (S54: YES), the control unit 6 determines that the abnormal discharge has occurred in the protective film 91, and performs a second notification process for notifying the cleaning of the protective film 91 (S55). Specifically, the control unit 6 causes the display unit 8 to indicate that the protective film 91 should be cleaned. On the other hand, when the abnormal discharge is not detected (S54: YES), the control unit 6 determines that the photoconductor drum 31K has an abnormal discharge, and performs a second notification process for notifying the replacement of the photoconductor drum 31K. (S55). Specifically, the control unit 6 causes the display unit 8 to indicate that the photoconductor drum 31K should be replaced.

The same effect as that of the first embodiment can be obtained in the image forming apparatus 1 of the second embodiment described above. That is, the control unit 6 can notify the user of cleaning of the charger 40 when the charging voltage detected by the voltage detecting unit 65 is equal to or higher than a predetermined threshold value (S45).

Further, when the charging voltage of the charging wire 41 detected by the voltage detection unit 65 is less than a predetermined threshold value, the user is notified that the photoconductor drum 31K is to be removed, and the user notifies the user that the photoconductor drum 31K is removed from the image forming apparatus 1. After the removal, if the occurrence of abnormal discharge is not detected, the user can be notified of the replacement of the photoconductor drum 31K (S55). On the other hand, even if the photoconductor drum 31K is removed, the user can be notified of the cleaning of the protective film 91 if the occurrence of abnormal discharge is detected (S54).

As described above, according to the image forming apparatus 1 of the second embodiment, it is possible to appropriately notify the user of the location where the abnormal discharge occurs. As a result, the recurrence of the abnormal discharge can be prevented by encouraging the user to clean or replace the member at the location where the abnormal discharge occurs.

[Other Embodiments]
In the image forming apparatus 1 in the above-described embodiment, the control unit 6 detects the occurrence of abnormal discharge based on the charging voltage value detected by the voltage detecting unit 65, but the present invention is not limited to this. For example, the control unit 6 may detect the occurrence of abnormal discharge based on the charge current value detected by the current detection unit 66. That is, the occurrence of abnormal discharge is caused by detecting the charging current value of a value larger than the normal value that momentarily flows through the charger 40 due to the occurrence of abnormal discharge in the charger 40 by the current detection unit 66. It may be detected.

Further, the control unit 6 may detect the occurrence of abnormal discharge based on both the charging voltage detected by the voltage detecting unit 65 and the charging current detected by the current detecting unit 66. Further, the image forming apparatus 1 does not necessarily have to include both the voltage detection unit 65 and the current detection unit 66, and may include at least one of the voltage detection unit 65 and the current detection unit 66.

Further, in the above-described embodiment, the threshold value used when notifying the cleaning of the charger 40 and the threshold value used when notifying the cleaning of another member other than the charger 40 may be set to different values. For example, the threshold value of the charger 40 may be set to about 6.6 [kV], and the threshold value of another member other than the charger 40 may be set to about 5.0 [kV].

In the above-described embodiment, when some notification is given to the user, the notification content is displayed on the display unit 8, but the present invention is not limited to this, and the user is made to recognize the notification content by, for example, voice output from the speaker. May be good.

Further, the voltage detection unit 65 detects the charging voltage applied to the charging wire 41 of the charging device 40, but is not limited to this, and the charging voltage of both the charging wire 41 and the grid 42 of the charging device 40 is detected. It may be detected. In this case, the control unit 6 detects the occurrence of abnormal discharge based on the charging voltage values of both the charging wire 41 and the grid 42 detected by the voltage detecting unit 65, and thus provides redundancy for detecting the occurrence of abnormal discharge. Can be secured.

Further, in the above-described embodiment, the voltage detection unit 65 detects the charging voltage applied to the charger 40, but the present invention is not limited to this. For example, a non-contact type potential sensor (ESV: Electro Static Voltmeter) is provided near the charger 40, and the control unit 6 detects the occurrence of abnormal discharge based on the detection signal from the potential sensor. May be good.

The image forming apparatus 1 described above is said to be a color printer or a monochrome printer, but the present invention is not limited to this, and any other apparatus having a printing function, such as a multifunction device or a FAX apparatus, can be applied. Further, the control unit 6 of the image forming apparatus 1 may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or may be realized by software.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

1 Image forming device 6 Control unit 7 Cover 8 Display unit 9 Fan 23 Conveyance belt 25Y, 25M, 25C, 25K Transfer roller 31Y, 31M, 31C, 31K Photoreceptor drum 40 Charger 40Y Transmission wire 41 Charging wire 42 Grid 64 Charging voltage Applying unit 65 Voltage detecting unit 66 Current detecting unit 91 Protective film

Claims (8)

Photoreceptor and
A charger that charges the photoconductor and
A detection unit that detects at least one of a charging voltage applied to the charging device and a charging current flowing through the charging device due to the application of the charging voltage.
Control unit and
With
The control unit
An abnormal discharge detection process that detects the occurrence of an abnormal discharge based on at least one of the charging voltage and the charging current detected by the detection unit.
Specific processing for specifying at least one of the charging voltage and the charging current when the abnormal discharge is detected, and
When at least one of the charging voltage and the charging current when the abnormal discharge is detected is equal to or higher than a predetermined threshold value, the first notification process for notifying the user of the cleaning of the charger and the abnormal discharge are performed. When at least one of the charging voltage and the charging current at the time of detection is less than a predetermined threshold value, a second notification process for notifying the user of replacement or cleaning of a member different from the charger is executed. An image forming apparatus characterized by performing notification processing. In the second notification process, the control unit executes a process of notifying the user that the photoconductor will be removed from the image forming apparatus.
After the photoconductor is removed from the image forming apparatus, the control unit is in a state where a charging voltage is applied to the charger.
(I) If the occurrence of the abnormal discharge is not detected, a process of notifying the user of replacement or cleaning of the photoconductor is executed.
(Ii) The image formation according to claim 1, wherein if the occurrence of the abnormal discharge is detected, a process of notifying the user of replacement or cleaning of the charger and another member other than the photoconductor is executed. apparatus. The separate member includes a first separate member and a second separate member.
In the second notification process, the control unit executes a process of notifying the user of the removal of the first separate member.
After the first separate member is removed from the image forming apparatus while leaving the photoconductor, the control unit is in a state where a charging voltage is applied to the charging device.
(I) If the occurrence of the abnormal discharge is not detected, a process of notifying the user of replacement or cleaning of the first separate member is executed.
(Ii) When the occurrence of the abnormal discharge is detected, a process of notifying the user that the photoconductor is to be removed from the image forming apparatus is executed, and after the photoconductor is removed from the image forming apparatus, the charger is used. In the state where the charging voltage is applied to
(A) If the occurrence of the abnormal discharge is not detected, a process of notifying the user of replacement or cleaning of the photoconductor is executed.
(B) The image forming apparatus according to claim 2, wherein if the occurrence of the abnormal discharge is detected, a process of notifying the user of replacement or cleaning of the second separate member is executed. The image forming apparatus according to claim 3, wherein the first separate member is a transport belt for transporting recording paper. The image forming apparatus according to claim 3 or 4, wherein the second separate member is provided at a position corresponding to a power transmission wire connecting the charger and the ground. A fan for exhausting the air inside the image forming apparatus is provided.
The image forming apparatus according to claim 5, wherein the second separate member is a protective member that protects the deposits from adhering to the power transmission wire by the fan. A plurality of the photoconductors are provided,
The charger is provided at a position corresponding to the plurality of photoconductors, respectively.
The image forming apparatus includes a charging voltage application unit that applies a charging voltage to each of the plurality of charging devices.
The charging voltage applying unit applies the charging voltage to each of the plurality of charging devices in order.
The detection unit detects at least one of the charging voltage of each of the plurality of charging devices and the charging current flowing through each of the plurality of charging devices by applying the charging voltage.
The control unit performs an abnormal discharge at a location corresponding to each charger based on at least one of the charging voltage of each of the plurality of chargers detected by the detection unit and each charging current of the plurality of chargers. The image forming apparatus according to any one of claims 1 to 6, wherein the occurrence of is detected and the user is notified of replacement or cleaning of a member at a location corresponding to each charger. The charger has at least a charging wire and
The image forming apparatus according to any one of claims 1 to 7, wherein the detection unit detects at least one of the charging voltage of the charging wire and the charging current of the charging wire. ..

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