JP6965558B2 - How to determine the life of image forming equipment and ozone filter - Google Patents

Description

The present invention relates to an improvement in a technique for determining the life of an ozone filter provided in an image forming apparatus such as a printer.

In an electrophotographic image forming apparatus such as a printer, the surface of a charged image carrier is exposed and scanned to form an electrostatic latent image, and the imaged electrostatic latent image is developed with a developer such as toner. After forming the developer image, the image is formed on the recording sheet by transferring the developer image to the recording sheet.
Each step of charging and transferring is performed by applying a high voltage to a discharging member such as a charging charger or a transfer charger to generate a discharge. Along with this discharge, discharge products such as ozone are generated in the air inside the aircraft, and by removing the ozone with an ozone filter, the ozone generated inside the aircraft is not discharged to the outside of the aircraft.

Normally, the ozone filter has a reduced collecting capacity as the amount of ozone collected increases, and finally reaches the end of its life. When the ozone filter reaches the end of its life, for example, a serviceman or the like performs work to replace it with a new one.
Patent Document 1 discloses a configuration in which the replacement time of the ozone filter is determined by using the cumulative energization time of the current flowing from the high-voltage transformer to the corona charger.

Japanese Unexamined Patent Publication No. 3-186863

However, in the configuration using the cumulative energization time described above, there is a problem that the replacement time of the ozone filter cannot be accurately determined.
That is, the amount of ozone generated by the discharge of a charged charger or the like depends not only on the cumulative energization time of the current flowing through the corona charger, but also on the magnitude of the current value. For example, changes in the electrical resistance of charged chargers and transfer chargers due to the surrounding environment and durability, changes in electrical resistance due to a decrease in the thickness of the photoconductor, and electrical resistance of each sheet when different types of recording sheets are used. Differences The current value that flows may differ depending on the job execution period and the surrounding environment. Even if the energization time of the current flowing through the corona charger is the same each time a job is executed, the amount of ozone generated differs due to the difference in the current value between the job executed at one time and the job executed at another time. Will happen.

Therefore, in the configuration of Patent Document 1, even if the cumulative energization time of the current flowing through the corona charger is short, the ozone filter has already reached the end of its life in the first case, or even if the cumulative energization time is long, ozone is used. There may be a second case where there is still room to reach the end of the filter life.
In the first case, it will be late even if the replacement work is performed when the ozone filter replacement time is determined, and in the second case, the ozone filter that has not reached the end of its life, that is, the ozone filter that can still be used is replaced. This is contrary to cost reduction.

The above problems are not limited to the charging and transfer steps, but are static elimination chargers and static elimination needles that perform a static elimination step for separating the recording sheet from a discharge member that is a source of ozone, for example, a photoconductor or an intermediate transfer body. The same occurs in the configuration having the above.
The present invention has been made in view of the above problems, and is an image forming apparatus capable of more accurately determining the replacement time of the ozone filter in a configuration having a discharge member, and a method for determining the life of the ozone filter. It is intended to be provided.

In order to achieve the above object, the image forming apparatus according to the present invention performs at least one step of charging, transferring, and static elimination by discharging a discharge member provided for each step, and generates ozone generated in the air by the discharge. It is an electrophotographic image forming device that removes with an ozone filter, and calculates the amount of current obtained by time-integrating the current value flowing through the discharge member with the energization time each time a process involving discharge is executed. It is provided with a calculation means for calculating an index value for indexing the magnitude of the value obtained by accumulating all of them and a judgment means for determining the life of the ozone filter based on the index value . Among them, a first discharge member for executing the first step and a second discharge member for executing the second step are provided, and the image forming apparatus further includes a duct and the first discharge in the apparatus. The calculation means includes a fan that guides air containing ozone generated by the discharge of the member and air containing ozone generated by the discharge of the second discharge member through the duct to the ozone filter. Each time the process is executed, the current value flowing through the first discharge member is time-integrated with the energization time to calculate the first current amount, and the current value flowing through the second discharge member is calculated with the energization time each time the second step is executed. The second current amount time-integrated in is calculated, the calculated first current amount and the second current amount are each given a predetermined weight, and then the weighted first current amount and the second current amount are accumulated. In addition, the predetermined weighting is such that the air flow flow path between the first discharge member and the ozone filter is larger than the air flow flow path between the second discharge member and the ozone filter. When the distance is short, the weight for the first current amount is larger than the weight for the second current amount .

Further, it is an electrophotographic image forming apparatus that performs at least one step of charging, transferring, and eliminating static electricity by discharging a discharge member provided for each step, and removes ozone generated in the air by the discharge with an ozone filter. Then, each time a process involving discharge is executed, the current value obtained by time-integrating the current value flowing through the discharge member with the energization time is calculated, and the index value indicating the magnitude of the value obtained by cumulatively adding all the calculated current amounts. A first discharge member for executing the first step of each of the charging, transferring, and static elimination steps, which comprises a calculating means for calculating the current value and a determining means for determining the life of the ozone filter based on the index value. And a second discharge member for executing the second step, and further, the image forming apparatus includes a duct, air containing ozone generated by the discharge of the first discharge member in the apparatus, and the second discharge member. The calculation means includes a fan that guides air containing ozone generated by the discharge of the discharge member through the duct to the ozone filter , and the calculation means is a current flowing through the first discharge member each time the first step is executed. The first current amount was calculated by time-integrating the value with the energization time, and the second current amount was calculated by time-integrating the current value flowing through the second discharge member with the energization time each time the second step was executed. After performing predetermined weighting on each of the first current amount and the second current amount, the first current amount and the second current amount after the weighting are cumulatively added, and the predetermined weighting is applied to the first discharge member. When the wind speed WV1 of the air flow at the position of is weaker than the wind speed WV2 of the air flow at the position of the second discharge member, the weight with respect to the first current amount is smaller than the weight with respect to the second current amount. It is characterized in that it is performed in such a manner.

Further, a measuring means for measuring the current value flowing through the discharge member may be provided, and the calculating means may use the measured value by the measuring means as the current value flowing through the discharge member.
Further, the calculation means may estimate the current value flowing through the discharge member from the cumulative energization time of the discharge member or the cumulative number of images formed.
Further, the discharge member is provided with a power supply means for supplying electric power to the discharge member, and the discharge member is a charging member that contacts the image carrier to charge the image carrier, and the power supply means is the image at the time of image formation. An AC voltage including an inter-peak voltage having a magnitude such that a discharge current flows between the carrier and the charged member is supplied to the charged member, and the calculation means measures the discharge current flowing between the image carrier and the charged member. The current value of Ip may be obtained, and the obtained current value may be used as the current value flowing through the discharge member.

Here, when the discharge start voltage to the image carrier when a DC voltage is applied to the charging member is Vth, the region where the peak-to-peak voltage Vpp of the AC voltage is less than (Vth × 2) is the undischarged region. When the region where the peak voltage Vpp is (Vth × 2) or more is defined as the discharge region, the power supply means has a plurality of charging voltages including AC currents, and in each of the undischarged region and the discharged region. Each of the plurality of charging voltages having different peak voltage of the AC current is sequentially applied to the charging member at the time of non-image formation, and the calculation means is a characteristic straight line of the AC current value with respect to the peak voltage Vpp in the undischarged region. Characteristics of AC current value with respect to peak voltage Vpp in the discharge region The peak voltage Vy of the AC voltage included in the charging voltage used at the time of image formation is determined based on the peak voltage Vx at the intersection of the straight line L2, and further determined. The current value of the discharge current Ip may be estimated from the peak voltage Vy and the characteristic lines L1 and L2.

Further, it is an electrophotographic image forming apparatus in which at least one step of charging, transferring, and static elimination is performed by discharging a discharge member provided for each step, and ozone generated in the air due to the discharge is removed by an ozone filter. Then, each time a process involving discharge is executed, the current value obtained by time-integrating the current value flowing through the discharge member with the energization time is calculated, and the index value indicating the magnitude of the value obtained by cumulatively adding all the calculated current amounts. calculation means for calculating the life of the determination means and the ozone filter based on the transition of the magnitude of the previous SL the index value calculated each time the execution of the step of determining the lifetime of the ozone filter based on the index value A predictive means for predicting the arrival time and the time from the present to the predicted life arrival time are calculated, and when the calculated time is less than or equal to a predetermined time, the predicted life arrival time is notified and the calculated time is calculated. It is characterized by comprising a notification means that does not notify the predicted end-of-life time when it is longer than the predetermined time .
In the method for determining the life of an ozone filter according to the present invention, at least one step of charging, transferring, and static elimination is performed by discharging a discharge member provided for each step, and the ozone generated in the air due to the discharge is removed by the ozone filter. This is a method for determining the life of an ozone filter in an electrophotographic image forming apparatus, and is calculated by calculating the amount of current obtained by time-integrating the current value flowing through the discharge member with the energization time each time a process involving discharge is executed. The image forming apparatus is executed by executing a step including a calculation step of calculating an index value of the magnitude of a value obtained by cumulatively adding all of the current amounts and a determination step of determining the life of the ozone filter based on the index value. Is provided with a first discharge member for executing the first step and a second discharge member for executing the second step among the steps of charging, transferring, and static elimination, and further, a duct and a inside of the device. The calculation includes an air containing ozone generated by the discharge of the first discharge member and a fan for guiding the air containing ozone generated by the discharge of the second discharge member through the duct to the ozone filter. In the step, the first current amount is calculated by integrating the current value flowing through the first discharge member with the energization time each time the first step is executed, and the current value flows through the second discharge member each time the second step is executed. A second current amount obtained by time-integrating the current value with the energization time is calculated, and after performing predetermined weighting on each of the calculated first current amount and the second current amount, the weighted first current amount and the second current amount are applied. Each of the amounts is cumulatively added, and the predetermined weighting is such that the air flow flow path between the first discharge member and the ozone filter is the air flow between the second discharge member and the ozone filter. When the distance is shorter than the flow path of the above, the weight for the first current amount is larger than the weight for the second current amount .
Further, at least one step of charging, transferring, and static elimination is performed by discharging a discharge member provided for each step, and ozone generated in the air due to the discharge is removed by an ozone filter. This is a method for determining the life of a filter, which is a method of determining the life of a filter. A step including a calculation step of calculating an index value of size and a determination step of determining the life of the ozone filter based on the index value is executed, and the image forming apparatus performs each step of charging, transferring, and eliminating static electricity. Of these, a first discharge member for executing the first step and a second discharge member for executing the second step are provided, and further, it is generated by the discharge of the duct and the first discharge member in the apparatus. The calculation step includes a fan that guides the air containing ozone and the air containing ozone generated by the discharge of the second discharge member through the duct to the ozone filter, and the calculation step is performed every time the first step is executed. The first current amount obtained by time-integrating the current value flowing through the first discharge member with the energization time was calculated, and the current value flowing through the second discharge member was time-integrated with the energization time each time the second step was executed. The two current amounts are calculated, the calculated first current amount and the second current amount are each given a predetermined weighting, and then the weighted first current amount and the second current amount are cumulatively added, and the predetermined weighting is performed. When the wind speed WV1 of the air flow at the position of the first discharge member is weaker than the wind speed WV2 of the air flow at the position of the second discharge member, the weight with respect to the first current amount is the first. 2 It is characterized in that it is performed so as to be smaller than the weight with respect to the amount of current.
Further, at least one step of charging, transferring, and static elimination is performed by discharging a discharge member provided for each step, and ozone generated in the air due to the discharge is removed by an ozone filter. A method for determining the life of a filter, which is a method of determining the life of a filter. The calculation step of calculating the index value of the magnitude, the determination step of determining the life of the ozone filter based on the index value, and the transition of the magnitude of the index value calculated each time the step is executed. The prediction step for predicting the life reaching time of the ozone filter and the time from the present to the predicted life reaching time are calculated, and when the calculated time is less than the predetermined time, the predicted life reaching time is notified. When the calculated time is longer than the predetermined time, the step including the notification step of not notifying the predicted end-of-life time is executed.

According to the above configuration, the life of the ozone filter is determined according to the magnitude of the cumulative current amount obtained by multiplying the current value flowing through the discharge member by the energization time. It is possible to determine the replacement time of the ozone filter more accurately than the configuration in which the determination is made only from the cumulative energization time as described above.

It is a schematic front view which shows the structure of the image forming apparatus which concerns on Embodiment 1. FIG. It is a figure which shows the structure of the power-source part. It is a block diagram which shows the structure of a control part. (A) is a diagram illustrating a graph of a change in the voltage of the secondary transfer bias output during execution of a print job for printing on two sheets of continuously conveyed paper, and (b) is a diagram illustrating the state of change in the voltage of the secondary transfer bias. It is a figure which illustrates the graph of the state of the change of the current value flowing through the secondary transfer roller by the supply of the output voltage of the secondary transfer bias. It is a flowchart which shows the content of the life determination process of an ozone filter. (A) and (b) are diagrams for explaining the weighting coefficient used for weighting the amount of current according to the second embodiment. It is a figure which shows the example of the table in which the weighting coefficient which concerns on Embodiment 3 are written. It is a figure for demonstrating the method of estimating the discharge current in the structure of the AC charging system which concerns on Embodiment 4. FIG. It is a flowchart which shows the content of the discharge current estimation processing. It is a figure which shows the example of the table which associated the peak voltage and the current value. (A) and (b) are diagrams showing an example of a table in which the environmental condition, the durability condition, and the current value of the charging roller are associated with each other according to the fifth embodiment. It is a figure which shows the graph for demonstrating the control which predicts the time when the cumulative current amount exceeds a threshold value in Embodiment 6. It is a figure which shows the structural example of the table which shows the correspondence relationship between the elapsed time and the cumulative current amount. It is a flowchart which shows the content of the prediction process of the life end time of an ozone filter.

Hereinafter, embodiments of the image forming apparatus and the method for determining the life of the ozone filter according to the present invention will be described with reference to the drawings.
<Embodiment 1>
(1) Configuration of Image Forming Device FIG. 1 is a schematic front view showing the configuration of an image forming apparatus.

As shown in the figure, the image forming apparatus 1 is a tandem type color printer, which executes a print job transmitted from an external terminal device (not shown) via a network, specifically, a color toner. Print the image on a recording sheet such as paper.
The image forming apparatus 1 is an electrophotographic method, and has an image forming unit 10Y, 10M, 10C, 10K, an exposure unit 15, an intermediate transfer unit 20, a paper feeding unit 30, a static elimination unit 35, a fixing unit 40, and a control unit 50. A power supply unit 60, an operation unit 70, and an ozone removal unit 80 are provided.

The image forming unit 10K includes a photoconductor drum 11 that rotates in the direction of arrow A, a charged charger 12K arranged around the photoconductor drum 11, a developing unit 13, a cleaner 14, and the like, and is black on the photoconductor drum 11. K) Create a color toner image.
Here, in the charging charger 12K, a wire 122 that is not in contact with the surface of the photoconductor drum 11 is surrounded by a shield 121 from three sides, and a charging bias from the power supply unit 60 is supplied to the wire 122. By supplying this charging bias, corona discharge is performed from the wire 122 to the surface of the photoconductor drum 11, and the surface of the photoconductor drum 11 is charged. Instead of the configuration using the wire 122, for example, a scorotron type charging device having a needle electrode and further having a grid electrode between the needle electrode and the photoconductor drum 11 can be used.

The image-forming units 10Y, 10M, and 10C have basically the same configuration as the image-creating unit 10K, and the reference numerals are omitted in the figure except for the charged chargers 12Y, 12M, and 12C.
The image forming unit 10Y images a yellow (Y) color toner image, the image forming unit 10M images a magenta (M) color toner image, and the image forming unit 10C produces a cyan (C) color toner image. Create a toner image. In the above description, the photoconductor drum 11 is used as the image carrier, but the present invention is not limited to this, and for example, a photoconductor belt or the like can be used.

In addition to the intermediate transfer belt 21 arranged above the image forming unit 10Y to 10K, the intermediate transfer unit 20 includes a drive roller 22, a driven roller 23, a primary transfer roller 24Y, 24M, 24C, 24K, and a secondary transfer roller. It has 25 and the like.
The intermediate transfer belt 21 is stretched by the drive roller 22, the driven roller 23, and the primary transfer rollers 24Y to 24K, and is driven orbiting in the direction of arrow B.

The primary transfer rollers 24Y to 24K are arranged to face the photoconductor drum 11 of the image forming unit 10Y to 10K via the intermediate transfer belt 21. The secondary transfer roller 25 is arranged to face the drive roller 22 via the intermediate transfer belt 21. Each of the primary transfer rollers 24Y to 24K and the secondary transfer roller 25 are formed by laminating a layer of an elastic material made of conductive rubber or the like around a metal shaft core, and the metal shaft core is formed by laminating. Is supplied with a transfer bias from the power supply unit 60.

Of the peripheral surface of the secondary transfer roller 25, the portion facing the peripheral surface of the intermediate transfer belt 21 comes into contact with the peripheral surface of the intermediate transfer belt 21 to form the transfer nip 25a, and the portion other than the transfer nip 25a is intermediate. It is in non-contact with the peripheral surface of the transfer belt 21, and in the non-contact region, due to the curvature of the peripheral surface of the secondary transfer roller 25, as it moves away from the transfer nip 25a in the circumferential direction, it becomes in contact with the peripheral surface of the intermediate transfer belt 21. The gap (space) between them becomes larger.

Of the non-contact region, the portion near the transfer nip 25a has an extremely small gap, and when the secondary transfer bias is supplied to the secondary transfer roller 25, the secondary transfer is performed in the transfer nip 25a, which is the contact region. The secondary transfer is executed by the current flowing from the roller 25 to the intermediate transfer belt 21 and the discharge current due to the discharge flowing in the small gap in the non-contact region. This also applies to the primary transfer rollers 24Y to 24K.

Regarding the primary transfer, a configuration example using the primary transfer rollers 24Y to 24K in contact with the intermediate transfer belt 21 has been described above, but the transfer is not limited to the contact type transfer by the roller shape. For example, a transfer charger having a wire that performs corona discharge in a non-contact manner, such as the above-mentioned charged chargers 12Y to 12K, may be used. Similarly, instead of the charging chargers 12Y to 12K, for example, a charging roller that comes into contact with the surface of the photoconductor drum 11 may be used.

The exposure unit 15 is arranged below the image forming units 10Y to 10K, and the light beams Ly, Lm, Lc, and Lk are set by the drive signal from the control unit 50 of the corresponding image forming units 10Y, 10M, 10C, and 10K. Emit toward the photoconductor drum 11.
Before the light beams Ly to Lk are emitted, the photoconductor drum 11 is uniformly charged by the charging chargers 12Y to 12K in the image forming units 10Y to 10K, and the charged photobeam drum 11 is irradiated with the light beam. As a result, the photoconductor drum 11 is exposed and scanned. By this exposure scanning, an electrostatic latent image is formed on each of the photoconductor drums 11 of the image forming portions 10Y to 10K.

The electrostatic latent image formed on the photoconductor drum 11 for each image forming unit 10Y to 10K corresponds to the image forming unit by being developed by receiving the supply of toner as a developer by the developing unit 13. A toner image (developer image) of the desired color is formed on the photoconductor drum 11.
In the image forming unit 10Y to 10K, the toner image formed on the photoconductor drum 11 is primarily transferred to the intermediate transfer belt 21 by the primary transfer rollers 24Y to 24K. At this time, the image forming operation of each color is executed at different timings so that the toner image is superimposed and transferred to the same position on the intermediate transfer belt 21.

The cleaner 14 removes the residual toner remaining on the photoconductor drum 11 without being transferred from the photoconductor drum 11 to the intermediate transfer belt 21 during the primary transfer for each of the image forming portions 10Y to 10K.
The paper feed unit 30 includes a paper feed cassette 31 that accommodates the paper S as an example of a recording sheet, a feeding roller 32 that feeds the paper S in the paper feed cassette 31 one by one onto the transport path 39, and the fed paper. It is provided with a transport roller 33 for transporting S, a timing roller 34 for transporting the paper S at a timing of feeding the paper S to be transported to the transfer nip 25a (secondary transfer position), and the like. Hereinafter, the transfer nip is referred to as a secondary transfer position 25a.

The timing roller 34 conveys the paper S to the secondary transfer position 25a at the timing when the Y to K color toner images multiple-transferred on the intermediate transfer belt 21 are conveyed to the secondary transfer position 25a. Then, when the paper S passes through the secondary transfer position 25a, the toner image on the intermediate transfer belt 21 is secondarily transferred onto the paper S by the secondary transfer roller 25.
The static elimination unit 35 is located near the secondary transfer position 25a and downstream of the secondary transfer position 25a in the paper transport direction, and is discharged by the separation bias supplied from the power supply unit 60 to generate the secondary transfer position. The paper S that has passed through 25a is discharged.

Here, the static elimination unit 35 is made of a thin plate made of metal, for example, about 500 [μm], and has a long shape along the width direction of the paper S (direction orthogonal to the transport direction: corresponding to the vertical direction of the paper surface in the figure). , The side on the tip side facing the secondary transfer position 25a is formed in a saw shape. Since the tip of this saw-shaped tooth is formed in a needle shape, it is hereinafter referred to as a static elimination needle.
Immediately after the tip of the paper S on which the toner image is secondarily transferred has passed the secondary transfer position 25a, the paper S is peeled off from the intermediate transfer belt 21 by the static elimination action of the static elimination needle 35 and is conveyed toward the fixing portion 40. NS.

The fixing portion 40 is arranged above the secondary transfer position 25a, includes a fixing roller 41 and a pressure roller 42 that is pressed against the fixing roller 41, and fixes the paper S conveyed by the secondary transfer roller 25 to the fixing roller 41. The toner image (unfixed image) on the paper S is heat-fixed by heating and pressurizing the toner image (unfixed image) on the paper S through the fixing nip formed by the pressurizing roller 42. The fixing roller 41 is maintained at a predetermined fixing temperature (for example, 170 ° C.) required for fixing by the heat of the heater 43.

The paper S that has passed through the fixing portion 40 is discharged to the outside of the image forming apparatus 1 by the discharge roller 45, and is housed in the paper discharge tray 46. Each roller such as the photoconductor drum 11, the intermediate transfer belt 21, the feeding roller 32, and the fixing roller 41 is rotationally driven by the rotational driving force of the driving motor M.
The ozone removing unit 80 has a long duct 81, a fan 82, and an ozone filter 83, and among the above-mentioned charging, exposure, developing, transfer, static elimination, and fixing steps, charging and transfer (primary) accompanied by electric discharge. And secondary), remove ozone generated in the air by executing static elimination.

Specifically, in the duct 81, each of the suction port 88 on one end side in the longitudinal direction and the discharge port 89 on the other end side are open, and the suction port 88 is located inside the device housing 2 (inside the machine). The discharge port 89 communicates with the space outside the device housing 2 (outside the machine).
The fan 82 is arranged at a position intermediate in the longitudinal direction of the duct 81, and the ozone filter 83 is fitted into the discharge port 89 of the duct 81.

When the fan 82 rotates, the air inside the machine containing ozone is sucked into the duct 81 from the suction port 88 of the duct 81. The air sucked into the duct 81 passes through the fan 82, toward the discharge port 89 of the duct 81, and passes through the ozone filter 83 provided in the discharge port 89 (arrow 29 indicated by the broken line). At the time of this passage, discharge products such as ozone contained in the air flowing through the duct 81 are collected by the ozone filter 83. By the ozone removal function of the ozone filter 83, the air after the discharge products such as ozone are removed is discharged from the duct 81 to the outside of the machine. The ozone filter 83 can be replaced by a service person or the like, and when the replacement period (life) is reached, the old product is replaced with a new one.

The operation unit 70 is arranged on the front surface of the image forming apparatus 1 at a position where it is easy for the user to operate, and is provided with a key for receiving a setting input of the number of prints by the user, a key for receiving a selection input of various modes, and the like. In addition, a display unit 70a for displaying a warning message or the like indicating that the ozone filter 83 needs to be replaced because the replacement time has been reached is provided.
The environment sensor 16 detects the temperature, humidity, or both in the machine. This detection result is used to determine when to replace the ozone filter 83.

In the above description, the static elimination needle is used as the static elimination unit 35, but the present invention is not limited to this. For example, instead of the static elimination needle, a static elimination charger having a non-contact corona discharge wire such as a charging charger 12Y to 12K is used. It can also be configured to be used.
(2) Configuration of Power Supply Unit FIG. 2 is a diagram showing a configuration of a power supply unit 60.

As shown in the figure, the power supply unit 60 includes DC power supplies 61Y, 61M, 61C, 61K, DC power supplies 62Y, 62M, 62C, 62K, and DC power supplies 63, 64.
The DC power supplies 61Y to 61K supply a DC voltage of, for example, 4 to 5 k (kilo) V as a charging bias to the charging chargers 12Y to 12K.
The DC power supplies 62Y to 62K supply a DC voltage of, for example, 0.5 to 0.6 kV as a primary transfer bias to the primary transfer rollers 24Y to 24K.

The DC power supply 63 supplies a DC voltage of, for example, 2 kV to the secondary transfer roller 25 as a secondary transfer bias, and the DC power supply 64 supplies a DC voltage of, for example, 2 to 4 kV as a static elimination bias to the static elimination needle 35.
An ammeter 5 as a current measuring unit for measuring the current value flowing through the charged charger 12K is provided in the middle of the electric circuit connecting the DC power supply 61K and the charged charger 12K. The current value measured by the ammeter 5 is used to determine the life of the ozone filter 83.

In the middle of the electric path connecting the DC power supply 62K and the primary transfer roller 24K, an ammeter 6 is provided as a current measuring unit for measuring the current value flowing through the primary transfer roller 24K, and the DC power supply 63 and the secondary transfer roller 24K are provided. In the middle of the electric path connecting the 25, an ammeter 7 is provided as a current measuring unit for measuring the current value flowing through the secondary transfer roller 25. Similarly, an ammeter 8 as a current measuring unit for measuring the current value flowing through the static elimination needle 35 is provided in the middle of the electric circuit connecting the DC power supply 64 and the static elimination needle 35. The current value measured by each of the ammeters 6 to 8 is also used for determining the life of the ozone filter 83 in the same manner as the current value measured by the ammeter 5. This life determination method will be described later.

In the present embodiment, the polarity of the toner as a developer is negative polarity, and the development is performed by so-called reverse development. Therefore, the charge bias is the same polarity as the toner, which is negative polarity, primary transfer and secondary transfer. The bias has a positive polarity, which is the opposite polarity to the toner, and the static elimination bias has a negative polarity, which is the opposite polarity to the secondary transfer bias. When the polarity of the toner is positive, the polarities of charging, transfer, and static elimination are opposite to those described above. Further, the bias voltage is a DC voltage, but the present invention is not limited to this, and for example, an AC voltage obtained by superimposing an AC on the DC voltage may be used.

(3) Configuration of Control Unit FIG. 3 is a block diagram showing a configuration of the control unit 50.
As shown in the figure, the control unit 50 includes an interface (I / F) unit 101, a CPU (Central Processing Unit) 102, a ROM (Read Only Memory) 103, a RAM (Random Access Memory) 104, an image processing unit 105, and an image. A memory 106, an output voltage indicating unit 107, a cumulative current amount calculation unit 108, a cumulative current amount storage unit 109, a threshold storage unit 110, and a timer 111 are provided, and each of them can communicate with each other.

The I / F unit 101 is an interface for connecting to a network such as a LAN board, and when receiving print job data transmitted from an external terminal device via the network, the print job data is image-processed. Send to unit 105.
The image processing unit 105 converts the print job data into image data of the reproduction colors Y to K, outputs the converted image data to the image memory 106, and stores the converted image data in the image memory 106 for each job.

When the print job is executed, the CPU 102 controls the image forming units 10Y to 10K, the intermediate transfer unit 20, and the like to execute a color printing operation based on the image data stored in the image memory 106. In addition, the fan 82 is driven to rotate during job execution or regardless of whether or not the job is executed. Further, the life of the ozone filter 83 is determined.
The ROM 103 stores a program necessary for the CPU 102 to execute each process such as a print operation and a life determination of the ozone filter 83. The RAM 104 is used as a work area of the CPU 102 when executing a program.

The output voltage indicating unit 107 instructs the power supply unit 60 to output the charging bias, the primary transfer bias, the secondary transfer bias, and the static elimination bias. The output voltage of each bias is predetermined.
FIG. 4A is a diagram illustrating a graph of a change in the voltage of the secondary transfer bias output during execution of a print job for printing on two sheets of paper S that are continuously conveyed. Here, the secondary transfer bias is controlled by a constant voltage.

In the graph Fv of the figure, the time when the leading edge of the first sheet S in the conveying direction (the leading edge of the sheet) reaches the secondary transfer position 25a is t1, and the rear edge of the first sheet S in the conveying direction (rear edge of the sheet). The time when It is shown by t4.
Between the time points t1 to t2 and between the time points t3 to t4, it is the time during which the paper S is passing through the secondary transfer position 25a, and the secondary transfer bias voltage Va is 2 kV. On the other hand, the secondary transfer bias voltage Vb is 0.5 kV instead of 0 V between the time points t2 to t3, which is the so-called paper-to-paper relationship in which the secondary transfer to the paper S is not executed.

This takes into consideration the time required for the rise of the output voltage of the secondary transfer bias. That is, between the time points t2 to t3 between papers, even if the output of the secondary transfer bias is stopped (0 V), the secondary transfer is not affected, and the power is saved when the output is stopped. However, the time between the time points t2 to t3 is extremely short, such as 100 ms. Therefore, if the output is restarted immediately after the output of the secondary transfer bias is completely stopped at the time point t2, the secondary transfer bias voltage Va is still generated at the time point t3 depending on the length of time required for the output voltage to rise. It has not reached 2 kV, and it is likely that it will reach 2 kV after the time point t3 has passed. If this happens, the transferability to the tip of the second sheet of paper will decrease.

Therefore, between the time points t2 to t3 between the papers, the output voltage of the secondary transfer bias is made lower than that of the normal Va in consideration of the rising time of the output voltage of the secondary transfer bias, and the tip of the second sheet of paper is used. Is reduced to a voltage Vb (> 0) that can reach Va when the secondary transfer position 25a is reached, so as to save power and prevent deterioration of transferability to the tip of the second sheet. ing.

FIG. 4B is a diagram illustrating a graph of a change in the current value flowing through the secondary transfer roller 25 due to the supply of the output voltage of the secondary transfer bias shown in FIG. 4A.
In the graph Fi of the figure, the current value Ia is 200 μA from t1 when the front edge of the first sheet reaches the secondary transfer position 25a to t2 when the rear edge of the sheet passes through the secondary transfer position 25a. The current value Ib is 50 μA between the time points t2 to t3 between the papers, and the secondary transfer position 25a is from the time point t3 when the front end of the second sheet reaches the secondary transfer position 25a. The current value Ic is 175 μA up to t4 at the time of passing through.

The current values Ia to Ic can be measured by the ammeter 7 during job execution, and by monitoring the measured value of the ammeter 7, the current value flowing through the secondary transfer roller 25 and the energization time during job execution can be measured. A graph (function) Fi showing the relationship can be calculated.
As shown in FIG. 4 (a), the output voltage Va of the secondary transfer bias is the same value for both the first sheet S and the second sheet S, but FIG. 4 (b) shows. As shown in the above, the current values Ia and Ic flowing through the secondary transfer roller 25 are slightly different. It is considered that this is because the electric resistance value of the first sheet S and the electric resistance value of the second sheet S are slightly different.

As described above, the amount of ozone generated during discharge changes depending on the magnitude of the current flowing through the secondary transfer roller 25, which is a discharge member. Therefore, the amount of ozone generated during secondary transfer to the first sheet S and the amount of ozone generated during secondary transfer Strictly speaking, there is a difference from the amount of ozone generated during the secondary transfer to the second sheet S.
The generated ozone is collected by the ozone filter 83. The life of the ozone filter 83 is determined by the cumulative amount of ozone collected from the time of new product to the present. The cumulative amount of ozone collected by the ozone filter 83 is related to the amount of ozone generated by the discharge, and the amount of ozone generated is related to the magnitude of the current flowing through the discharge member during the discharge.

Specifically, the larger the current value flowing through the discharge member during discharging, the larger the amount of ozone generated, the larger the amount of ozone collected by the ozone filter 83, and the shorter the remaining life of the ozone filter 83. Become. That is, it can be said that the magnitude of the current value flowing through the discharge member affects the life of the ozone filter 83.
In FIG. 4, an example in which the secondary transfer roller 25 is used as a discharge member has been described, but other discharge members, that is, the charging charger 12K, the primary transfer roller 24K, and the static elimination needle 35 also have a large current value flowing through them. Affects the life of the ozone filter 83.

From this, for example, if the configuration is as follows, the remaining life of the ozone filter 83 can be indexed from the value of the current flowing through each discharge member.
That is, during job execution, the value Pi (current amount: corresponding to the area Ps of the shaded portion shown in FIG. 4B) obtained by integrating the current value flowing through the discharge member for each discharge member with the energization time is graph Fi (function). ), And the total current amount Pa obtained by summing the obtained current amounts Pi is calculated.

For example, assuming that the current amount of the charged charger 12K in one job is P1, the current amount of the primary transfer roller 24K is P2, the current amount of the secondary transfer roller 25 is P3, and the current amount of the static elimination needle 35 is P4, the total current is The amount Pa is (P1 + P2 + P3 + P4).
Then, the cumulative current amount Pb obtained by accumulating the total current amount Pa calculated every time the job is executed after the ozone filter 83 is new is obtained. This cumulative current amount Pb can be said to be an index value that indicates the magnitude of the value obtained by cumulatively adding all of the total current amount Pa calculated from the time when the ozone filter 83 is new to the present. Further, the cumulative current amount Pb is also an index of the cumulative amount of ozone collected by the ozone filter 83 after the new product, that is, the remaining life of the ozone filter 83. Specifically, the larger the cumulative current amount Pb, the larger the amount of ozone generated by the discharge, and the shorter the remaining life of the ozone filter 83.

If the assumed value of the cumulative current amount Pb at the time when the ozone filter 83 reaches the end of its life is determined in advance from experiments or the like with the threshold th1 as the threshold th1, when the cumulative current amount Pb after the new ozone filter 83 exceeds the threshold th1, It can be determined that the ozone filter 83 has reached the end of its life. By this control, the amount of ozone generated, which changes depending on the magnitude of the current value flowing through the discharge member, is added to the life judgment of the ozone filter 83. The replacement time of 83 can be determined more accurately.

In the above, since the image forming units 10Y to 10K have basically the same configuration, the current value flowing through the charging chargers 12Y to 12K is substantially the same for all charging chargers, and the current flowing through the primary transfer rollers 24Y to 24K. Assuming that the values are almost the same for all primary transfer rollers, measure the current values of the charged charger 12K for K color and the primary transfer roller 24K with ammeters 5 and 6, and the current values for the other Y to C colors. Was not measured, but it is not limited to this. The current values flowing through the Y, M, and C colored chargers 12Y, 12M, and 12C and the current values flowing through the primary transfer rollers 24Y, 24M, and 24C are also individually measured with an ammeter and reflected in the above cumulative current amount Pb. It may be configured. In the case of this configuration, the threshold value th1 is set in advance from an experiment or the like so that the life can be determined from the magnitude relationship with the cumulative current amount Pb formed by cumulatively adding the current amounts of all the discharge members.

Returning to FIG. 3, the cumulative current amount calculation unit 108 calculates the total current amount Pa based on the measured values of the ammeters 5 to 8 for each job execution, and stores the calculated total current amount Pa in the cumulative current amount storage unit. The value added to the cumulative current amount Pb actually stored in 109 is calculated as a new cumulative current amount Pb. Then, the cumulative current amount Pb actually stored in the cumulative current amount storage unit 109 is rewritten to the calculated cumulative current amount Pb to update the cumulative current amount Pb.

The threshold storage unit 110 stores the above-mentioned threshold th1.
The timer 111 is used for each discharge member to measure the energization time when measuring the current value flowing through the discharge member with an ammeter. The graph Fi (function) shown in FIG. 4B is obtained for one discharge member based on the measured energization time and the measured current value, and the current amount Pi is calculated from the graph Fi. The total current amount Pa is calculated by adding the calculated current amounts Pi of each discharge member.

(4) Ozone filter life determination process FIG. 5 is a flowchart showing the contents of the ozone filter life determination process, and the process is performed by a main routine (not shown) each time the control unit 50 starts executing a job. Executed by being called.
As shown in the figure, when the job is started (step S1), the current values measured by the ammeters 5 to 8 are acquired at predetermined sampling intervals for each of the charging, primary transfer, secondary transfer, and static elimination steps. And memorize (step S2). The sampling interval is timed by a timer 111, for example, 0.1 second.

Acquisition and storage of the current value is continued until the end of the job is determined (“No” in step S3), and when the end of the job is determined (“Yes” in step S3), charging, primary transfer, secondary transfer, For each step of separation, the current amount Pi, which is the value obtained by integrating the stored current value with the energization time, is calculated (step S4). This calculation is performed using the graph Fi shown in FIG. 4 (b).
For example, the current amount P1 can be set for the charging step, the current amount P2 can be set for the primary transfer step, the current amount P3 can be set for the secondary transfer step, and the current amount P4 can be set for the static elimination step.

Then, the total current amount Pa, which is the sum of the calculated current amounts Pi, is obtained (step S5). In the above example, Pa = (P1 + P2 + P3 + P4).
The cumulative current amount Pb currently stored in the cumulative current amount storage unit 109 is read out, and the value obtained by adding the total current amount Pa calculated in step 5 to the read cumulative current amount Pb is calculated as a new cumulative current amount Pb. (Step S6).

Then, it is determined whether or not the new cumulative current amount Pb calculated in step S6 is larger than the threshold value th1 (step S7). The threshold value th1 is read from the threshold value storage unit 110.
When it is determined that the relationship of the new cumulative current amount Pb ≤ threshold th1 is satisfied (“No” in step S7), the cumulative current amount Pb actually stored in the cumulative current amount storage unit 109 is obtained in step 6. The cumulative current amount Pb is rewritten with a new cumulative current amount Pb to update the cumulative current amount Pb (step S8), and the process returns. As a result, all of the total current amounts Pa calculated from the time when the ozone filter 83 is new to the present are cumulatively added to obtain the cumulative current amount Pb.

On the other hand, when it is determined that the new cumulative current amount Pb> threshold th1 relationship is satisfied (“Yes” in step S7), it is notified that the ozone filter 83 has reached the replacement time due to the life of the ozone filter 83 (“Yes”). Step S9). This notification is performed, for example, by displaying a message on the display unit 70a of the operation unit 70. It suffices if the user, the serviceman, or the like can be notified, and for example, a voice output can be used, or information indicating that fact can be transmitted to the terminal device owned by the serviceman via the network.

When it is determined that the ozone filter 83 has been replaced from an old product to a new one by replacement work by a user or a service person (“Yes” in step S10), the cumulative current amount Pb actually stored in the cumulative current amount storage unit 109 Is reset to 0 (zero) (step S11) and returns. The determination that the ozone filter 83 has been replaced with a new one means that, for example, the user or the like presses a key (not shown) provided on the operation unit 70 indicating the completion of replacement after the replacement work is completed. It can be done by judgment.

As described above, in the present embodiment, the life of the ozone filter 83 is determined in consideration of the magnitude of the current value flowing through the discharge member such as the charged charger. It is possible to determine the replacement time of the ozone filter 83 more accurately than the configuration in which the life is determined from the above.
As a result, it is possible to prevent the ozone filter 83 from being replaced even if the replacement work is performed when the replacement time is determined as in the first case above, and the ozone that can still be used as in the second case can be prevented. It is possible to reduce the cost by preventing the filter from being replaced.
<Embodiment 2>
In the first embodiment, a configuration example is described in which the total current amount Pa is calculated by summing the current amounts P1 to P4 for the discharge members (charged charger, transfer roller, static elimination needle) in each step of charging, transferring, and static elimination. However, in the second embodiment, the total current amount Pa is calculated by weighting each of the current amounts P1 to P4 and summing the weighted current amounts P1 to P4. It is different from the first embodiment. Hereinafter, in order to avoid duplication of description, the description of the same content as that of the first embodiment will be omitted.

FIG. 6 is a diagram for explaining a weighting coefficient used for weighting, FIG. 6A shows an example of an apparatus using a toner having a negative polarity as a toner as a developer, and FIG. 6B shows an example of an apparatus using a toner having a positive polarity. An example of another device using one is shown.
As described above, the polarities of the charging bias, the transfer bias, and the static elimination bias are determined by the polarity of the toner or the charging polarity of the photoconductor drum 11. When the polarity of the toner is negative as in the first embodiment, the bias voltage supplied to the charging charger and the static elimination needle becomes negative as shown in FIG. 6A, and the bias voltage supplied to the transfer roller becomes positive. Become.

Weighting is performed based on the difference in the amount of ozone generated in each of the charging, transferring, and static elimination steps. That is, the amount of ozone generated by the discharge differs depending on the difference in the polarity (plus and minus) of the bias voltage supplied to the discharge member. Specifically, it is known that there are more negative polarities than positive polarities. In addition, the amount of ozone generated differs depending on the electrode shape of the discharge member, specifically, the wire, roller, and needle electrode. Of the wire, roller, and needle electrode, the non-contact type wire generates ozone. It is also known that there are the most and the few contact rollers.

In FIG. 6A, in consideration of the difference in the polarity of the bias voltage, the negative polarity charging charger and the static elimination needle have a larger weighting coefficient than the positive polarity transfer roller, and the difference in the electrode shape is taken into consideration. Therefore, an example is shown in which a value in which the weighting coefficient of the charged charger is set to be larger than that of the static elimination needle is set.
The table 201 in which the weighting coefficient shown in FIG. 6A is written is obtained and stored in advance by an experiment or the like. The control unit 50 weights as follows. That is, in the process of obtaining the total current amount Pa (step S5 in FIG. 5), each current amount Pi calculated in step 4 is multiplied by the weighting coefficient Z shown in Table 201.

Specifically, assuming that the weighting coefficient for the charging charger is Z1, the weighting coefficient for the transfer roller is Z2, and the weighting coefficient for the static elimination needle is Z3, the current amount P1 × Z1 for the charging bias and the current amount P2 × for the primary transfer bias. The current amount is P3 × Z2 for Z2 and the secondary transfer bias, and the current amount is P4 × Z3 for the static elimination bias. Therefore, the total current amount Pa is calculated as [(P1 × Z1) + (P2 × Z2) + (P3 × Z2) + (P4 × Z3)]. The amount of current after the weighting coefficient Z is multiplied is called the amount of current after weighting. The cumulative current amount Pb is calculated from the current amounts P1 to P4 after this weighting. The cumulative current amount Pb to which the weighting is added is also the total amount calculated from the time when the ozone filter 83 is new to the present, similarly to the cumulative current amount Pb (the one without the weighting) in the first embodiment. It can be said that it is an index value that indicates the magnitude of the value obtained by cumulatively adding all of the current amount Pa.

FIG. 6B is also an example in which the weighting coefficient is set in consideration of the difference in both the polarity of the bias voltage and the electrode shape as in FIG. 6A, but the difference in the electrode shape is the difference in the bias voltage. Since the difference in the amount of ozone generated is usually larger than the difference in polarity, the positive polarity charged charger has a larger weighting coefficient than the negative polarity transfer roller.
The table 202 shown in FIG. 6B is also obtained and stored in advance by an experiment or the like in the same manner as the table 201. Needless to say, the value of the weighting coefficient Z is not limited to the above, and a value suitable for determining the life of the ozone filter 83 is set for each device configuration. Further, the weighting is not limited to the method performed by multiplying the weighting coefficient Z, and other methods may be used as long as different weights based on the difference in the electrode shape and the like can be added to each current amount Pi.

As described above, in the second embodiment, since the current amount Pi of each discharge member is weighted according to the difference in the polarity of the bias voltage and the electrode shape, the amount of ozone generated even with the same current amount Pi for each discharge member. When the values are different, the cumulative current amount Pb, which indicates the life of the ozone filter 83, reflects the difference in the amount of ozone generated due to the difference in the polarity of the bias voltage and the electrode shape, and the life of the ozone filter 83 is extended accordingly. The accuracy of determining when the time is reached (replacement time) can be further improved.
<Embodiment 3>
In the second embodiment, the weighting is performed according to the difference in the electrode shape and the like, but in the third embodiment, the weighting is performed according to the difference in the distance between each discharge member and the ozone filter 83. This point is different from the second embodiment.

FIG. 7 is a diagram showing an example of a table 211 in which the weighting coefficient according to the third embodiment is written.
As shown in the figure, among the charged chargers 12Y to 12K as discharge members, the weighting coefficient Zy for the charged charger 12Y arranged at the position farthest from the ozone filter 83 is 1, and the weighting coefficient Zy for the charged charger 12M next to it is 1. 2. The weighting coefficient Zy for the charged charger 12C next to it is 3, and the weighting coefficient Zy for the charged charger 12K located closest to the ozone filter 83 is 4. The distance from the ozone filter 83 to the discharge member is the air in the machine up to the ozone filter 83 after the air containing ozone generated by the discharge of each discharge member is sucked into the duct 81 by the fan 82. Indicates the length of the flow path.

Ozone generated by electric discharge has the property of returning to the original oxygen over time in the air. Therefore, the longer it takes for the generated ozone to reach the ozone filter 83, that is, the longer the distance to the ozone filter 83 if the air flow velocity is constant, the more the original ozone is reached when it reaches the ozone filter 83. The proportion of those returning to oxygen increases. This means that even if the amount of ozone generated by each of the charged chargers 12Y to 12K is the same, the amount of ozone reaching the ozone filter 83 is larger than that of ozone generated by the charged charger 12Y farthest from the ozone filter 83. It means less ozone generated by the charged charger 12K closest to the ozone filter 83.

Since the weighting is performed on the current amount Pi, which is the calculation source of the cumulative current amount Pb that indicates the remaining life of the ozone filter 83, the charging charger 12K having a large amount of ozone reaching the ozone filter 83 has a smaller charging charger. When the weighting coefficient Z is made larger than that of 12Y, the life of the ozone filter 83 can be determined by reflecting the difference in the amount of ozone generated due to the difference in the distance from the discharge member to the ozone filter 83.

In the table 211 shown in FIG. 7, the weighting coefficient Z is the minimum 1 for the primary transfer rollers 24Y to 24K because of the roller shape, and the roller shape for the secondary transfer roller 25. However, since it is arranged at a position considerably close to the ozone filter 83 and the static elimination needle 35 is also close to the ozone filter 83, the weighting coefficient Z is set to 4, which is the same as the charging charger 12K.

Further, the weighting is not limited to the above distance, and the weighting can be set according to the flow velocity (wind speed) of the air flow in the machine until the air containing ozone reaches the ozone filter 83, for example.
Specifically, when comparing the charged chargers 12Y and 12K, the wind speed at the position of the charged charger 12Y, which is far from the duct 81, due to the positional relationship between the charged chargers 12Y and 12K and the duct 81 provided with the ozone filter 83. The WV1 is weaker than the wind speed WV2 at the position of the charged charger 12K, which is closer to the duct 81.

When the relationship of wind speed WV1 <WV2 is satisfied, the weighting of the charged charger 12Y located at the weak position of the wind speed WV1 is smaller than that of the charged charger 12K located at the strong position of the wind speed WV2. The weaker the wind speed, the longer the air containing ozone stays in the place, and the larger the proportion of the generated ozone that returns to oxygen, so the weighting is reduced. In this sense, the cumulative current amount Pb including weighting can be said to be a value indicating the amount of ozone existing at the time when the ozone-containing air generated by the discharge of the charged charger reaches the ozone filter 83.

As described above, in the third embodiment, since weighting is performed according to the difference in the distance (or wind velocity) from each discharge member to the ozone filter 83, the ozone filter 83 is generated even if the amount of ozone generated is the same for each discharge member. The cumulative current amount Pb, which is an index of the life of the ozone filter 83, reflects the difference in the amount of ozone at the time of reaching the ozone filter 83 due to the above distance (or wind velocity). As a result, the accuracy of determining when the ozone filter 83 has reached the end of its life (replacement time) can be further improved as compared with the configuration in which weighting is not performed.
<Embodiment 4>
In the first to third embodiments, a charging charger that is not in contact with the photoconductor drum 11 is used as the discharge member that charges the photoconductor drum 11 by electric discharge. However, in the fourth embodiment, the photoconductor drum 11 is charged. It is configured to use a charging roller that comes into contact with the surface of 11, and is different from the first to third embodiments in this respect.

When such a contact-type charging roller is used, a discharge phenomenon similar to that of the transfer roller described above, that is, a region of the peripheral surface of the charging roller to which the charging bias is supplied, which is in contact with the surface of the photoconductor drum 11 ( While the current flows through the charging nip), the discharge current due to the discharge flows in the non-contact region near the charging nip and having a minute gap with the surface of the photoconductor drum 11, so that charging is performed.

Of the current and discharge current flowing through the charging nip, the discharge current is proportional to the amount of ozone generated, but the current meter 5 connected in series with the charging roller measures both the current flowing through the charging nip and the discharge current. Since the included current value is measured, it is not possible to measure only the discharge current that is proportional to the amount of ozone generated. Since the current flowing through the current meter 5 contains a component of the discharge current, it goes without saying that the current value measured by the current meter 5 is an index of the amount of ozone generated, but the magnitude of the discharge current. The life of the ozone filter 83 can be determined by reflecting only the amount of ozone generated by the discharge in the configuration that can measure only the current.

Therefore, in the fourth embodiment, the discharge current that cannot be measured by the ammeter 5 is estimated by the following method, and the estimated value is replaced with the measured value of the ammeter 5, so that the accuracy of determining the life of the ozone filter 83 is further improved. I am trying to improve it.
FIG. 8 is a diagram for explaining a method of estimating the discharge current in a so-called AC charging method configuration in which a charging voltage in which an AC voltage is superimposed on a DC voltage is supplied to a charging roller, and the horizontal axis is the peak of the AC voltage. The peak-to-peak voltage Vpp (V), which is the two-peak voltage, is shown, and the vertical axis shows the alternating current Iac (μA) flowing through the charging roller.

The undischarged region shown in the figure is a region in which the peak voltage Vpp is less than (Vth × 2) when the discharge start voltage to the photoconductor drum 11 when a DC voltage is applied to the charging roller is Vth. The discharge region refers to a region in which the peak voltage Vpp is (Vth × 2) or more.
The inter-peak voltage Vpp and the AC current Iac have a linear relationship in the undischarged region (graph L1), and in the discharged region, the current gradually increases with respect to the graph L1 as the inter-peak voltage Vpp increases. (Graph L2). The increment ΔIac of the alternating current Iac (the difference between the graphs L1 and L2 in the discharge region) is the increment of the current involved in the discharge, that is, the amount of discharge current that indicates the amount of discharge as a substitute. This is detailed in, for example, paragraph [0081] and FIG. 5 of the specification of Japanese Patent No. 4298107.

Assuming that the ratio of the alternating current Iac to the peak voltage Vpp shown in the graph L1 of FIG. 8 is α (0.4 in the example of the figure), the nip current flowing through the charged nip which is the contact portion other than the current due to the discharge is ( α × Vpp), and the following equation (1) is satisfied in the discharge region.
ΔIac = Iac− (α × Vpp) ・ ・ ・ (Equation 1)
From this (Equation 1), in the discharge region, (α × Vy) is the nip current In and (Iac-In) is the discharge current of the AC current Iac when the peak voltage Vpp is set to a certain value, for example, Vy. It turns out that it becomes Ip. The definitions of the nip current and the discharge current are detailed in paragraph [882] of the above-mentioned Japanese Patent No. 4298107.

The slopes of the graphs L1 and L2 change due to changes in the electrical resistance values of the photoconductor drum 11 and the charging roller, changes in the environment (temperature and humidity), and the like, and the magnitude of the peak voltage Vx at the intersection 3x of the graphs L1 and L2 can also change. If the peak voltage Vx at the intersection 3x is used as a reference to determine in advance how much the peak voltage should be increased to allow the discharge current Ip of a size suitable for charging to flow, it should be increased. By using the determined voltage Vz and the graphs L1 and L2, the inter-peak voltage Vy (= Vx + Vz) having a size suitable for charging can be obtained, and the current value of the discharge current Ip with respect to the inter-peak voltage Vy is also You can guess.

Graph L1 can be obtained as follows. That is, an AC voltage having a plurality of different peak-to-peak voltages V1, V2, V3, and V4 belonging to the undischarged region, in the example of FIG. 8, is applied to a predetermined constant DC voltage Vdc at the time of non-image formation. The four superimposed charging voltages are supplied to the charging rollers one by one in order.
Then, the AC current values I1, I2, I3, and I4 flowing through the charging roller are measured by the ammeter 5 for each of the four supplied charging voltages. Four plots 3a, 3b, 3c, and 3d were obtained from the correspondence between the peak voltage V1 to V4 and the AC current values I1 to I4. The relationship between alternating currents is linearly approximated to obtain an approximate straight line. The obtained approximate straight line is defined as the characteristic straight line (graph) L1 of the AC current value with respect to the peak voltage Vpp in the undischarged region.

The graph L2 can be obtained in the same manner. That is, at the time of non-image formation, an AC voltage having a plurality of different peak voltages V5, V6, V7, and V8 belonging to the discharge region, and four peak voltages V5, V6, V7, and V8 in the example of FIG. 8 was superimposed on the same constant DC voltage Vdc as described above. The four charging voltages are supplied to the charging rollers one by one in order. Then, the AC current values I5, I6, I7, and I8 flowing through the charging roller are measured by the ammeter 5 for each of the four supplied charging voltages. Four plots 3e, 3f, 3g, and 3h were obtained from the correspondence between the peak voltage V5 to V8 and the AC current values I5 to I8, and the peak voltage and AC in the discharge region were obtained from the obtained four plots 3e to 3h. Approximate straight line is obtained by linearly approximating the relationship between currents. The obtained approximate straight line is defined as the characteristic straight line (graph) L2 of the AC current value with respect to the peak voltage Vpp in the discharge region.

The inter-peak voltage Vy can be obtained from the graphs L1 and L2 obtained at the time of non-image formation, and the current value of the discharge current Ip corresponding to the obtained inter-peak voltage Vy can be calculated. At the time of image formation, if a charging voltage obtained by superimposing an AC voltage having a peak voltage Vy on the constant DC voltage Vdc is supplied to the charging roller, in the charging process, a discharge current Ip having the same magnitude as the calculated current value is obtained. Since it should flow, the calculated current value of the discharge current Ip becomes an estimated value, and the life of the ozone filter 83 can be determined using the estimated value.

The above V1 to V4 have a size of about belonging to the undischarged region (in other words, not belonging to the discharged region) even if the electric resistance value of the photoconductor drum 11 or the like changes or the environment changes. It is predetermined as an inter-peak voltage value. Similarly, V5 to V8 are also predetermined as inter-peak voltage values having a magnitude that belongs to the discharged region (in other words, does not belong to the undischarged region).

FIG. 9 is a flowchart showing the contents of the discharge current estimation process, which is executed by the control unit 50 at the time of non-image formation.
The variable i is set to 1 (step S21). Then, the power supply unit 60 is instructed to supply the charging roller with the charging voltage Vt1 in which the peak voltage Vi, here the AC voltage of V1 is superimposed, on the predetermined DC voltage Vdc (step S22). The current value Ii flowing through the charging roller by the ammeter 5, here I1 is measured (step S23), and the peak voltage V1 and the measured current value I1 are stored in association with each other (step S24). FIG. 10 is a diagram showing an example of a table 301 in which the peak voltage and the current value are associated with each other, and the table 301 is provided in a storage unit (not shown) of the control unit 50.

Returning to FIG. 9, it is determined whether or not the variable i is equal to N, here 8 (step S25). When it is determined that the variable i is not equal to N (“No” in step S25), the value obtained by incrementing “1” from the current variable i, here “2” is updated to a new variable i (step S26). , Return to step S22.
In step S22, the power supply unit 60 is instructed to supply the charging roller with a charging voltage Vt2 in which a predetermined DC voltage Vdc is superposed with an inter-peak voltage Vi, here, an AC voltage of V2.

Then, the current value Ii flowing through the charging roller by the ammeter 5, here I2 is measured (step S23), and the peak inter-peak voltage V2 and the measured current value I2 are stored in the table 301 in association with each other (step S24). ..
The processes of steps S22 to S26 are repeated until the variable i is determined to be equal to N. As a result, the peak inter-peak voltages V3 to V8 and the current values I3 to I8 are associated with each other and stored in the table 301 (see FIG. 10).

When it is determined that the variable i is equal to N (“Yes” in step S25), the approximate straight line L1 is calculated from the correspondence between the stored peak voltage V1 to V4 and the current values I1 to I4 (step S27). Subsequently, the approximate straight line L2 is calculated from the correspondence between the stored peak voltage V5 to V8 and the current values I5 to I8 (step S28).
The inter-peak voltage Vx at the intersection 3x is calculated from the straight lines L1 and L2 (step S29), and the value obtained by adding the predetermined value Vz to the calculated inter-peak voltage Vx is determined as the inter-peak voltage Vy (step S30). The current value of the discharge current Ip is calculated from the determined peak voltage Vy and the straight lines L1 and L2 (step S31). The determined peak voltage Vy and the calculated current value of the discharge current Ip are stored (step S32), and the process is terminated. The stored peak voltage Vy is used in the charging process at the time of image formation as described above, and the current value of the discharge current Ip is replaced with the current value flowing through the discharge member (charging roller) during job execution. It is used to calculate the total current amount Pa.

This discharge current estimation process is executed at the time of non-image formation. Specifically, when the device power is turned on (such as when the device is first turned on in the morning), the cumulative number of prints from the past to the present is a predetermined value (for example, a multiple of 1000). It is executed when the amount of change in the environment (temperature and humidity) exceeds a predetermined value each time the value of) is reached.
In the above, the peak voltage Vy suitable for charging is obtained by using the graphs L1 and L2, but the present invention is not limited to this. For example, when the target current value of the discharge current Ip is set in advance for each device, it can be controlled as follows.

That is, at the time of non-image formation, the magnitude of the peak-to-peak voltage Vpp should be set to the target current value from the graphs L1 and L2, and the obtained peak-to-peak voltage Ve is stored. Then, at the time of image formation, a charging voltage obtained by superimposing the AC voltage having the obtained peak voltage Ve on the constant DC voltage Vdc is supplied to the charging roller.
This control is AC constant current control, and even in the case of AC constant current control, the current value of the discharge current Ip should be the target current value in the charging process, so the ozone filter 83 uses that target current value as an estimated value. It becomes possible to judge the life of the.

As described above, in the fourth embodiment, since the current value of the discharge current Ip, which is proportional to the amount of ozone generated, is estimated, the life of the ozone filter 83 is determined rather than the configuration in which the current value including the nip current In is measured. The accuracy of the current can be improved.
<Embodiment 5>
In the first to third embodiments, the current flowing through the discharge member is actually measured, and in the fourth embodiment, the amount of ozone generated is indexed by estimating the discharge current. However, in the fifth embodiment, the actual measurement and estimation are performed. This is different from the first to fourth embodiments in that the current value flowing through the discharge member is estimated based on the predetermined environmental conditions and durability conditions.

FIG. 11A is a diagram showing an example of a table 501 in which environmental conditions, durability conditions, and current values of charging rollers are associated with each other. Environmental conditions are divided into three conditions: HH (high temperature and high humidity), NN (normal temperature and humidity), and LL (low temperature and low humidity). Hereinafter, it is referred to as "durability time").
Table 501 shows the results obtained from experiments and the like in advance as to how much current flows through the charging roller when a job is performed under a certain environmental condition in a certain endurance time. For example, when the endurance time is in the range of 0 to 1000 hours and the print job is executed in the NN environment, referring to Table 501, it is 100 μA, so this 100 μA is used as the current value flowing through the charging roller. The estimated current value Pi is obtained by integrating the estimated current value of 100 μA with the energization time. The environmental conditions are detected by the environmental sensor 16 shown in FIG. The endurance time is timed by timer 111 or another timer.

Similar to Table 501, by preparing a table that associates environmental conditions, durability conditions, and current values not only in the charging process but also in each transfer and static elimination process, each time a job is executed, For each discharge member, the current value (estimated value) corresponding to the environmental conditions and durability conditions at that time can be read from the table, and the current amount Pi obtained by integrating the read current value with the energization time can be obtained (FIG. 5). Step S4).

Compared with the configuration that actually measures the current value flowing through the discharge member, the error from the actual current amount tends to be large, but the life judgment is made more than the configuration that judges the life of the ozone filter 83 without considering the current value at all. The accuracy can be improved.
FIG. 11B is also a diagram showing an example of the table 502 in which the environmental condition, the durability condition, and the current value of the charging roller are associated with each other. As for the table 502, the table 501 shown in FIG. 11A is applied. An example of a table applied to a configuration in which the thickness of the photosensitive layer of the photoconductor drum 11 is thinner than that of the configuration is shown.

Specifically, when comparing the current values of the tables 501 and 502 in the range of 0 to 1000 hours and corresponding to the NN environment, the current values are 100 μA in the table 501 and 150 μA in the table 502. .. Looking at other combinations of endurance time and environmental conditions, it can be seen that the current value of Table 502 is larger than that of Table 501 under the same conditions. This is because the electric resistance value becomes smaller as the film thickness of the photoconductor drum 11 is thinner. Therefore, if the charging bias voltage is constant, the current value flowing through the charging roller is smaller because the electric resistance value of the photoconductor drum 11 is smaller. Is large. This is not limited to charging, and has the same relationship in, for example, the primary transfer step.

When the change in the current value depending on the thickness of the photoconductor drum 11 does not affect the life determination of the ozone filter 83 so much, one regardless of the thickness of the photoconductor drum 11. The table may be shared.
On the contrary, in a configuration in which the film thickness of the photoconductor drum 11 gradually decreases as the durability time increases, if a change in the film thickness affects the determination of the life of the ozone filter 83, for example, it is determined from the time of a new product. By controlling using the table 501 up to the time and using the table 502 when the predetermined time is exceeded, it is possible to estimate the current value closer to the actual measurement.

The above tables 501 and 502 are generated and stored in advance by obtaining a value suitable for the apparatus configuration by an experiment or the like, and the current values written in the tables 501 and 502 during the life determination process of the ozone filter 83. Is read out.
In the above, the environmental condition and the durability condition are combined, but the present invention is not limited to this. The accuracy of determining the life of the ozone filter 83 can be improved.

In addition, the example in which the durability condition is the cumulative energization time of the charging roller has been described, but the present invention is not limited to this, and any parameter that can index the change in resistance value due to long-term use of the charging roller may be used. It is also possible to use the cumulative number of image formations indicating the cumulative value of the number of prints from the time to the present.
<Embodiment 6>
In the first to fifth embodiments, when the cumulative current amount Pb exceeds the threshold value th1 (“Yes” in step S7 of FIG. 5), it is determined that the ozone filter 83 has reached the end of its life (step S9). However, in the sixth embodiment, the time when the cumulative current amount Pb exceeds the threshold value th1 is predicted from the transition of the rate of increase of the cumulative current amount Pb from the past to the present, and in this respect, the first embodiment 1 It is different from ~ 5.

FIG. 12 is a diagram showing a graph 601 for explaining the control for predicting the time when the cumulative current amount Pb exceeds the threshold value th1, where the horizontal axis is the elapsed time T from the time when the ozone filter 83 is new and the vertical axis is cumulative. The amount of current Pb is shown.
Looking at the transition of the cumulative current amount Pb from the time when the ozone filter 83 is new to the present Tp (for example, one year) from the graph 601 it can be seen that the elapsed time T and the cumulative current amount Pb are in a proportional relationship. .. By obtaining the equation of graph 601 in the figure, it is possible to predict the elapsed time Tz when the cumulative current amount Pb reaches the threshold value th1, that is, the time when the ozone filter 83 is expected to reach the life (life arrival time) Tz. ..

Graph 601 can be obtained as a prediction formula such as linear regression. Here, every time a unit time, for example, one day or one week elapses after the ozone filter 83 is new, the cumulative current amount Pb and the elapsed time T at that time are associated with each other, and the cumulative current amount storage unit is used. It is stored in the table of 109.
FIG. 13 is a diagram showing a configuration example of Table 610 showing the correspondence relationship between the elapsed time T and the cumulative current amount Pb. As the elapsed time T from the time of new product increases to T1, T2 ..., The cumulative current amount Pb increases to P1, P2 ... From the correspondence between the elapsed time T written in the table 610 and the cumulative current amount Pb between the time of new product and the present, the prediction formula showing the graph 601 is obtained to predict the life arrival time Tz.

If the life reaching time Tz can be predicted, for example, by displaying a message indicating the life reaching time Tz on the display unit 70a of the operation unit 70, the user or the serviceman is notified of a new product before the life reaching time Tz is reached. It is possible to notify that the ozone filter 83 is prepared in advance. It is also possible to make a reservation to the service person to replace the ozone filter 83 at the end of life Tz. As a result, parts of the ozone filter 83 can be ordered and replaced at an appropriate time, the cost required for the replacement work can be reduced, and inventory management can be simplified.

Further, for example, the image forming apparatus 1 transmits the predicted life arrival time Tz to an external service base via a network, so that the service base can order a new ozone filter 83 or make a reservation for replacement work by a service person. You can also build a system.
FIG. 14 is a flowchart showing the content of the prediction process of the end of life of the ozone filter 83, which is executed every time the control unit 50 reaches a predetermined time (for example, 9:00 am every day).

As shown in the figure, the current cumulative current amount Pb is read from the cumulative current amount storage unit 109 (step S51). Subsequently, the elapsed time T from the time when the ozone filter 83 is new to the present is obtained (step S52). The date and time of the new product (for example, 9:00 am on January 10, 2017) is registered in advance, and the elapsed time from the registered date and time to the current date and time (for example, 9:00 am on April 24, 2017). Is calculated. The elapsed time T and the current cumulative current amount Pb are associated with each other and written in the table 610 (step S53).

Then, a prediction formula (corresponding to graph 601) was obtained from the information indicating the correspondence between the elapsed time T from the time of new product to the present and the current cumulative current amount Pb written in the table 610, and the obtained prediction formula was obtained. Is used to predict the end-of-life time Tz (step S54).
From the present, the time Tx until the predicted life arrival time Tz is calculated (step S55). It is determined whether or not the time Tx is equal to or less than the predetermined time Ty (step S56). The predetermined time Ty is, for example, a time corresponding to 60 days.

When it is determined that the relationship of time Tx ≤ predetermined time Ty is satisfied (“Yes” in step S56), the end of life time Tz is notified (step S57), and the process ends. On the other hand, when it is determined that the relationship of time Tx> predetermined time Ty is satisfied (“No” in step S56), step S57 is skipped (notifying is not performed), and the process ends.
As a result, when the predicted life arrival time Tz is approached (about 2 months ago in the above example), the user or the like can be notified that the remaining life of the ozone filter 83 is shortened, so that a new product can be obtained. It is possible to give the user a preparation period such as ordering the ozone filter 83 of the above. On the other hand, if there is still time to replace the product (in the above example, the period until the end of life Tz is longer than 2 months), the notification is not given as soon as possible. You can prevent too many notifications. It should be noted that the user may be notified each time the life end time Tz is predicted. In addition, once the notification is given, it is possible to adopt a configuration in which the notification is not given thereafter. In the case of this configuration, in step S9 of FIG. 5, when the replacement time is reached, the fact that the replacement time has been reached will be notified.

The present invention is not limited to the image forming apparatus, and may be a method for determining the life of the ozone filter 83. Further, the method may be a program executed by a computer. The program according to the present invention includes, for example, magnetic tapes, magnetic disks such as flexible disks, optical recording media such as DVD-ROMs, DVD-RAMs, CD-ROMs, CD-Rs, MOs, and PDs, and flash memory recording media. It is possible to record on various computer-readable recording media such as, etc., and it may be produced or transferred in the form of the recording medium, or in the form of a program, various wired and wireless networks including the Internet. It may be transmitted and supplied via broadcasting, telecommunications lines, satellite communications, etc.

<Modification example>
Although the present invention has been described above based on the embodiments, the present invention is not limited to the above-described embodiments, and the following modifications can be considered.
(1) In the above embodiment, for each job execution, the current amount Pi is calculated for each of charging, transfer, and static elimination, and the calculated current amounts Pi are added to calculate the total current amount Pa to calculate the cumulative current amount. Pb was calculated, but it is not limited to this.

For example, the life of the ozone filter 83 can be determined by obtaining the cumulative current amount Pb of only the discharge member that performs any one of the charging, transferring, and static elimination steps.
For example, in the configuration where only the cumulative current amount Pb for the charged charger 12K is calculated, the amount of ozone generated in each step of transfer and static elimination is not taken into consideration, but the relationship between the amount of ozone generated by transfer and static elimination is also considered in advance from experiments and the like. Then, by setting the above-mentioned threshold th1 to a value suitable only for charging, the life can be determined more accurately than the configuration in which the life of the ozone filter is determined without considering the magnitude of the current value. ..

Further, it is also possible to obtain the cumulative current amount Pb from the current amount Pi of each of the first discharge member that performs one step of charging, transfer, and static elimination and the second discharge member that performs another step.
Of all the discharge members that are ozone generation sources, the larger the number of discharge members for which the current amount Pi is obtained, the greater the magnitude of the current value, which is an index value of the ozone generation amount for each discharge member, is reflected in the cumulative current amount Pb. Since it becomes easy, it can be expected that the accuracy of the life determination will be further improved.

(2) In the above embodiment, a configuration example in which the fan 82 is arranged in the duct 81 has been described as shown in FIG. 1, but the arrangement position of the fan 82 is not limited to this. Any position in the apparatus may be used as long as the air containing ozone generated by the discharge of each discharge member can be passed through the duct 81 and guided to the ozone filter 83. For example, the fan 82 is located outside the duct 81 and is arranged in the space between the suction port 88 of the duct 81 and the secondary transfer roller 25, and the air flow generated by the rotation of the fan 82 is discharged from the suction port 88 of the duct 81. It is also possible to adopt a configuration in which the air is fed into the duct 81.

(3) In the above embodiment, a configuration example of a tandem type color image forming apparatus has been described, but the present invention is not limited to this. It can be applied to an electrophotographic image forming apparatus in which any one or more steps of charging by electric discharge, transfer, and static elimination are executed by a discharge member provided in each process.
For example, in a configuration in which a toner image formed on one photoconductor drum is directly transferred to a recording sheet, charging of the photoconductor drum, transfer of the toner image from the photoconductor drum to the recording sheet, and transfer of the photoconductor drum after transfer are performed. It can also be applied to a monochrome image forming apparatus having a discharge member that performs either static elimination or static elimination of a recording sheet after transfer.

That is, the charging of the image carrier, the transfer of the image formed on the image carrier to the recording sheet or the transfer to the recording sheet via the intermediate transfer body, and the static elimination of the image carrier, the intermediate transfer body or the recording sheet. It can be applied to a configuration in which at least one of the steps is performed.
Further, it goes without saying that the above-mentioned numerical values such as time, temperature, current, and voltage are not limited to the above, and suitable values such as time and temperature are determined in advance by experiments or the like according to the device configuration.

Further, the contents of the above-described embodiment and the above-described modification may be combined as much as possible.

The present invention can be used in an image forming apparatus for forming an image on a recording sheet.

1 Image forming device 5, 6, 7, 8 Ammeter 11 Photoreceptor drum 12Y, 12M, 12C, 12K Charged charger 16 Environmental sensor 24Y, 24M, 24C, 24K Primary transfer roller 25 Secondary transfer roller 35 Static elimination needle 50 Control unit 60 Power supply unit 70a Display unit 80 Ozone removal unit 83 Ozone filter 108 Cumulative current amount calculation unit 109 Cumulative current amount storage unit 110 Threshold storage unit 111 Timer 201, 202, 211, 301, 501, 502, 610 Table

Claims (10)

An electrophotographic image forming apparatus in which at least one step of charging, transferring, and static elimination is performed by discharging a discharge member provided for each step, and ozone generated in the air due to the discharge is removed by an ozone filter.
Each time a process involving discharge is executed, the amount of current obtained by time-integrating the current value flowing through the discharge member with the energization time is calculated, and the index value indicating the magnitude of the value obtained by cumulatively adding all the calculated current amounts is calculated. Calculation method and
Judgment means for determining the life of the ozone filter based on the index value, and
With
Of the charging, transfer, and static elimination steps, a first discharging member for executing the first step and a second discharging member for executing the second step are provided.
Further, the image forming apparatus is
With the duct
The apparatus includes an ozone-containing air generated by the discharge of the first discharge member and a fan that guides the ozone-containing air generated by the discharge of the second discharge member through the duct to the ozone filter.
The calculation means is
Each time the first step is executed, the current value flowing through the first discharge member is time-integrated with the energization time to calculate the first current amount, and the current value flowing through the second discharge member is calculated each time the second step is executed. The second current amount time-integrated with the energization time is calculated, the calculated first current amount and the second current amount are each given a predetermined weighting, and then the weighted first current amount and the second current amount are respectively. Cumulatively add
The predetermined weighting is
When the air flow flow path between the first discharge member and the ozone filter is shorter than the air flow flow path between the second discharge member and the ozone filter, the first current images forming device you characterized by being performed to be greater than the weight for the second current amount is more weight to the amount. An electrophotographic image forming apparatus in which at least one step of charging, transferring, and static elimination is performed by discharging a discharge member provided for each step, and ozone generated in the air due to the discharge is removed by an ozone filter.
Each time a process involving discharge is executed, the amount of current obtained by time-integrating the current value flowing through the discharge member with the energization time is calculated, and the index value indicating the magnitude of the value obtained by cumulatively adding all the calculated current amounts is calculated. Calculation method and
Judgment means for determining the life of the ozone filter based on the index value, and
With
Of the charging, transfer, and static elimination steps, a first discharging member for executing the first step and a second discharging member for executing the second step are provided.
Further, the image forming apparatus is
With the duct
The apparatus includes an ozone-containing air generated by the discharge of the first discharge member and a fan that guides the ozone-containing air generated by the discharge of the second discharge member through the duct to the ozone filter.
The calculation means is
Each time the first step is executed, the current value flowing through the first discharge member is time-integrated with the energization time to calculate the first current amount, and the current value flowing through the second discharge member is calculated each time the second step is executed. The second current amount time-integrated with the energization time is calculated, the calculated first current amount and the second current amount are each given a predetermined weighting, and then the weighted first current amount and the second current amount are respectively. Cumulatively add
The predetermined weighting is
When the wind speed WV1 of the air flow at the position of the first discharge member is weaker than the wind speed WV2 of the air flow at the position of the second discharge member, the weight with respect to the first current amount is greater than the weight with respect to the second current amount. images forming device you comprises carrying out to be smaller than the weight. An electrophotographic image forming apparatus in which at least one step of charging, transferring, and static elimination is performed by discharging a discharge member provided for each step, and ozone generated in the air due to the discharge is removed by an ozone filter.
Each time a process involving discharge is executed, the amount of current obtained by time-integrating the current value flowing through the discharge member with the energization time is calculated, and the index value indicating the magnitude of the value obtained by cumulatively adding all the calculated current amounts is calculated. Calculation method and
Judgment means for determining the life of the ozone filter based on the index value, and
Prediction means for predicting the life end timing of the ozone filter based on the size of the transition of the previous SL the index values calculated in each execution of step,
The time from the present to the predicted life arrival time is calculated, and when the calculated time is less than or equal to the predetermined time, the predicted life arrival time is notified, and when the calculated time is longer than the predetermined time, Notification means that do not notify the predicted end of life time,
Images forming device you comprising: a. A measuring means for measuring the value of the current flowing through the discharge member is provided.
The calculation means is
The image forming apparatus according to any one of claims 1 to 3 , wherein the value measured by the measuring means is the value of the current flowing through the discharge member. The calculation means is
The image forming apparatus according to any one of claims 1 to 4 , wherein the current value flowing through the discharging member is estimated from the cumulative energizing time of the discharging member or the cumulative number of images to be formed. A power supply means for supplying electric power to the discharge member is provided.
The discharge member is a charging member that comes into contact with the image carrier and charges the image carrier.
At the time of image formation, the power supply means supplies the charging member with an AC voltage including an inter-peak voltage having a magnitude such that a discharge current flows between the image carrier and the charging member.
The calculation means is
The present aspect of any one of claims 1 to 5 , wherein the current value of the discharge current Ip flowing between the image carrier and the charging member is obtained, and the obtained current value is used as the current value flowing through the discharge member. The image forming apparatus according to the description. When the discharge start voltage to the image carrier when a DC voltage is applied to the charging member is Vth, the region where the peak voltage Vpp of the AC voltage is less than (Vth × 2) is the undischarged region, and the peak voltage. When the region where Vpp is (Vth × 2) or more is the discharge region,
The power supply means
A plurality of charging voltages including alternating currents, each of which has a different peak-to-peak voltage of the alternating current in each of the undischarged region and the discharged region, is applied to the charging member at the time of non-image formation. Apply sequentially,
The calculation means is
Characteristic of AC current value with respect to peak voltage Vpp in undischarged region Characteristic of AC current value with respect to peak voltage Vpp in discharged region Included in charging voltage used at the time of image formation based on peak voltage Vx at the intersection of straight line L2 The sixth aspect of claim 6, wherein the inter-peak voltage Vy of the AC voltage is determined, and the current value of the discharge current Ip is estimated from the determined inter-peak voltage Vy and the characteristic lines L1 and L2. Image forming device. An ozone filter in an electrophotographic image forming apparatus in which at least one step of charging, transferring, and static elimination is performed by discharging a discharge member provided for each step, and ozone generated in the air due to the discharge is removed by an ozone filter. It is a life judgment method,
Every time a process involving discharge is executed, the amount of current obtained by time-integrating the current value flowing through the discharge member with the energization time is calculated, and the index value of the magnitude of the value obtained by cumulatively adding all the calculated current amounts is calculated. Steps and
A judgment step for determining the life of the ozone filter based on the index value, and
Perform the steps including,
The image forming apparatus
Of the charging, transfer, and static elimination steps, a first discharging member for executing the first step and a second discharging member for executing the second step are provided.
In addition, with a duct,
A fan that guides air containing ozone generated by the discharge of the first discharge member and air containing ozone generated by the discharge of the second discharge member through the duct to the ozone filter in the apparatus.
With
The calculation step is
Each time the first step is executed, the current value flowing through the first discharge member is time-integrated with the energization time to calculate the first current amount, and the current value flowing through the second discharge member is calculated each time the second step is executed. The second current amount time-integrated with the energization time is calculated, the calculated first current amount and the second current amount are each given a predetermined weighting, and then the weighted first current amount and the second current amount are respectively. Cumulatively add
The predetermined weighting is
When the air flow flow path between the first discharge member and the ozone filter is shorter than the air flow flow path between the second discharge member and the ozone filter, the first current A method for determining the life of an ozone filter, characterized in that the weight with respect to the amount is larger than the weight with respect to the second current amount. An ozone filter in an electrophotographic image forming apparatus in which at least one step of charging, transferring, and static elimination is performed by discharging a discharge member provided for each step, and ozone generated in the air due to the discharge is removed by an ozone filter. It is a life judgment method,
Every time a process involving discharge is executed, the amount of current obtained by time-integrating the current value flowing through the discharge member with the energization time is calculated, and the index value of the magnitude of the value obtained by cumulatively adding all the calculated current amounts is calculated. Steps and
A judgment step for determining the life of the ozone filter based on the index value, and
Perform steps that include
The image forming apparatus
Of the charging, transfer, and static elimination steps, a first discharging member for executing the first step and a second discharging member for executing the second step are provided.
In addition, with a duct,
A fan that guides air containing ozone generated by the discharge of the first discharge member and air containing ozone generated by the discharge of the second discharge member through the duct to the ozone filter in the apparatus.
With
The calculation step is
Each time the first step is executed, the current value flowing through the first discharge member is time-integrated with the energization time to calculate the first current amount, and the current value flowing through the second discharge member is calculated each time the second step is executed. The second current amount time-integrated with the energization time is calculated, the calculated first current amount and the second current amount are each given a predetermined weighting, and then the weighted first current amount and the second current amount are respectively. Cumulatively add
The predetermined weighting is
When the wind speed WV1 of the air flow at the position of the first discharge member is weaker than the wind speed WV2 of the air flow at the position of the second discharge member, the weight with respect to the first current amount is greater than the weight with respect to the second current amount. A method for determining the life of an ozone filter, which is characterized in that it is performed so as to be smaller than the weight. An ozone filter in an electrophotographic image forming apparatus in which at least one step of charging, transferring, and static elimination is performed by discharging a discharge member provided for each step, and ozone generated in the air due to the discharge is removed by an ozone filter. It is a life judgment method,
Every time a process involving discharge is executed, the amount of current obtained by time-integrating the current value flowing through the discharge member with the energization time is calculated, and the index value of the magnitude of the value obtained by cumulatively adding all the calculated current amounts is calculated. Steps and
A judgment step for determining the life of the ozone filter based on the index value, and
A prediction step for predicting the time to reach the end of the life of the ozone filter based on the transition of the magnitude of the index value calculated each time the step is executed.
The time from the present to the predicted life arrival time is calculated, and when the calculated time is less than or equal to the predetermined time, the predicted life arrival time is notified, and when the calculated time is longer than the predetermined time, Notification steps that do not notify you of the expected end of life, and
A method for determining the life of an ozone filter, which comprises performing a step including.

Images