JP2017198864A - Image forming apparatus, method for calculating charging current, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of a low accuracy in calculating a charging current.SOLUTION: An image forming apparatus comprises: an image carrier on which an electrostatic latent image is formed; a charging part that charges the image carrier; a developing part that supplies a developer to the image carrier on which the electrostatic latent image is formed; a charging power supply that applies a voltage to the charging part; a developing power supply that applies a voltage to the developing part; a constant voltage member that is connected to the developing power supply to maintain the constant voltage at its both ends; a resistance member that has one end connected to the charging power supply and the other end connected to the developing power supply via the constant voltage member; a current detection part that detects a detection current including a charging current flowing in the charging part; and a control part that calculates the charging current flowing in the charging part on the basis of the detection current acquired while the charging power supply and the developing power supply are controlled on the basis of a predetermined voltage.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus, a charging current calculation method, and a program.

  An image forming apparatus in which a developing unit supplies a developer to a photosensitive member on which an electrostatic latent image is formed by charging by a charging unit to which a high voltage is applied from a high voltage power source and exposing the printed image to print the image. It has been known. In such an image forming apparatus, as the image is formed by printing or the like, the film thickness of the photoconductor decreases due to the shaving or the like. In view of this, in the image forming apparatus, a charging current flowing through the charging unit is detected by a current detection unit, and the film thickness of the photoconductor calculated from the charging current is calculated. In addition, in the image forming apparatus, a technique for reducing the cost of a high-voltage power supply or the like by sharing a charging and developing transformer is also disclosed.

  However, the above-described image forming apparatus has a problem that the calculation accuracy of the charging current is low because a current including a current other than the charging current is detected by a common transformer or the like.

  The present invention has been made in view of the above, and an object thereof is to improve the calculation accuracy of the charging current.

  In order to solve the above-described problems and achieve the object, an image forming apparatus of the present invention includes an image carrier on which an electrostatic latent image is formed, a charging unit that charges the image carrier, and the electrostatic latent image. A developing unit that supplies a developer to the image bearing member on which an image is formed; a charging power source that applies a voltage to the charging unit; a developing power source that applies a voltage to the developing unit; A constant voltage member for maintaining both ends thereof at a constant voltage, a resistance member having one end connected to the charging power source and the other end connected to the developing power source via the constant voltage member, and a charge flowing through the charging unit A current detection unit that detects a detection current including a current, and a charge that flows to the charging unit based on the detection current acquired in a state where the charging power source and the development power source are controlled based on a predetermined voltage. A control unit for calculating a current.

  According to the present invention, the charging current detection accuracy can be improved.

FIG. 1 is an overall configuration diagram of the image forming apparatus according to the first embodiment. FIG. 2 is a configuration diagram illustrating current and voltage in the image forming apparatus. FIG. 3 is a flowchart of main operation processing of the image forming apparatus by the control unit. FIG. 4 is a flowchart of the film thickness calculation process in the adjustment mode by the control unit. FIG. 5 is a configuration diagram illustrating the relationship between current and voltage and time in each member in the film thickness calculation process. FIG. 6 is a graph for explaining a method of calculating the slope of the charging current with respect to the charging voltage by the control unit. FIG. 7 is a graph illustrating the relationship between the slope of the charging current with respect to the charging voltage and the film thickness of the photoconductor. FIG. 8 is a diagram illustrating the voltage and current of the Zener diode that constitutes the constant voltage element. FIG. 9 is a graph showing the relationship between the voltage and current of the Zener diode and the temperature. FIG. 10 is a flowchart of the film thickness calculation process executed by the control unit. FIG. 11 is an example of a correction table used in the correction value determination process. FIG. 12 is a flowchart of the correction value determination process executed by the control unit.

  Similar components are included in the following exemplary embodiments and modifications. Therefore, below, the same code | symbol is attached | subjected to the same component, and the overlapping description is partially abbreviate | omitted. Portions included in the embodiments and modifications can be configured by replacing corresponding portions in other embodiments and modifications. In addition, the configuration, position, and the like of the parts included in the embodiments and modifications are the same as those in the other embodiments and modifications unless otherwise specified.

<First Embodiment>
FIG. 1 is an overall configuration diagram of an image forming apparatus 10 according to the first embodiment. As shown in FIG. 1, the image forming apparatus 10 includes an image forming unit 12, a high-voltage power supply unit 14, a temperature detection unit 16, and a control device 18.

  The image creating unit 12 creates an image corresponding to image information including electronic information on a medium such as paper. The image forming unit 12 includes a photoconductor 20, a charging roller 22, a developing unit 24, and a transfer roller 26.

  The photoconductor 20 is an example of an image carrier. An electrostatic latent image corresponding to an image to be printed is formed on the surface of the photoconductor 20 by being exposed in a charged state. The photoconductor 20 carries the formed electrostatic latent image.

  The charging roller 22 is provided in contact with the outer peripheral portion of the photoconductor 20. The charging roller 22 applies a charging voltage VC for forming an electrostatic latent image to the photoconductor 20 to uniformly charge the outer peripheral surface of the photoconductor 20. A charging voltage VC is applied to the charging roller 22 from the high voltage power supply unit 14. The charging roller 22 may have a chargeable configuration other than a roller shape such as charging.

  The developing unit 24 accommodates the developer, supplies the developer to the photoreceptor 20 on which the electrostatic latent image is formed, and develops the image. The developing unit 24 is an example of a developing unit. The developer includes, for example, a toner that forms an image and a carrier that conveys the toner to the photoconductor 20. The developing unit 24 includes a supply roller 28, a regulating blade 30, and a developing roller 32. A bias voltage is applied to the supply roller 28, the developing roller 32, and the regulation blade 30 from the high voltage power supply unit 14.

  The supply roller 28 supplies the stored developer to the development roller 32.

  The regulating blade 30 is arranged with a minute gap with respect to the outer peripheral surface of the developing roller 32. Thereby, the regulating blade 30 regulates the developer on the outer peripheral surface of the developing roller 32 supplied from the supply roller 28 to a constant layer thickness corresponding to the above-described minute interval. The regulating blade 30 may be in contact with the outer peripheral surface of the developing roller 32 with a minute pressure.

  The developing roller 32 is arranged on the outer peripheral surface of the photoconductor 20 with a minute interval. The developing roller 32 supplies the developer, which is supplied from the supply roller 28 and is regulated to a certain layer thickness by the regulating blade 30, to the electrostatic latent image on the photoconductor 20 and develops it.

  The transfer roller 26 applies pressure to the medium conveyed between the photoconductor 20 and the transfer roller 26. As a result, the transfer roller 26 transfers the developer of the electrostatic latent image formed on the outer peripheral surface of the photoconductor 20 to the medium to form an image.

  The high voltage power supply unit 14 supplies high voltage power to the charging roller 22 and the developing unit 24. The high-voltage power supply unit 14 includes a charging power supply 34, a development power supply 36, a first constant voltage element 38, a second constant voltage element 40, a current detection unit 42, and a resistance member 44.

  The charging power source 34 is connected to the charging roller 22. The charging power source 34 applies a high-voltage charging voltage VC for charging the photoconductor 20 to the charging roller 22.

  The development power source 36 is connected to the development unit 24 and applies a voltage to the development unit 24. Specifically, the developing power source 36 is directly connected to the developing roller 32. The development power source 36 applies a high development voltage VDV to the development roller 32. The development power source 36 is connected to the regulation blade 30 via the second constant voltage element 40. The development power source 36 applies a high regulation voltage VBL to the regulation blade 30. The development power source 36 is connected via the supply roller 28, the second constant voltage element 40, and the first constant voltage element 38. The development power source 36 applies a high supply voltage VR to the supply roller 28.

  The first constant voltage element 38 and the second constant voltage element 40 are connected to the developing power source 36 and maintain both ends thereof at a constant voltage. The first constant voltage element 38 and the second constant voltage element 40 are, for example, Zener diodes. The first constant voltage element 38 and the second constant voltage element 40 are connected in series. The first constant voltage element 38 and the second constant voltage element 40 connected in series are examples of a constant voltage member.

  One end of the first constant voltage element 38 is connected to the supply roller 28 and the resistance member 44, and the other end of the first constant voltage element 38 is connected to the regulating blade 30. As a result, the first constant voltage element 38 maintains the voltage between the supply roller 28 and the regulating blade 30 constant.

  One end of the second constant voltage element 40 is connected to the regulating blade 30, and the other end of the second constant voltage element 40 is connected to the developing power source 36 and the developing roller 32. As a result, the second constant voltage element 40 maintains a constant voltage between the regulating blade 30, the developing power source 36, and the developing roller 32.

  One end of the first constant voltage element 38 and the second constant voltage element 40 connected in series is connected to the supply roller 28 and the resistance member 44. The other ends of the first constant voltage element 38 and the second constant voltage element 40 connected in series are connected to the developing power source 36 and the developing roller 32. The first constant voltage element 38 and the second constant voltage element 40 maintain a constant voltage between the developing power source 36 and the developing roller 32, the supply roller 28, and the resistance member 44.

  The current detection unit 42 detects a detection current Is that is a current including a charging current flowing through the charging roller 22. The current detection unit 42 outputs the detected detection current Is to the control device 18.

  One end of the resistance member 44 is connected to the charging power source 34 and the charging roller 22. The other end of the resistance member 44 is connected to the first constant voltage element 38 and the supply roller 28. Thereby, one end of the resistance member 44 is connected to the charging power source 34, and the other end of the resistance member 44 is connected to the developing roller 32 and the developing power source 36 via the first constant voltage element 38 and the second constant voltage element 40. The As a result, when the voltage output from the charging power source 34 and the developing power source 36 is constant, a constant voltage is applied to the resistance member 44 by the first constant voltage element 38 and the second constant voltage element 40.

  The temperature detection unit 16 detects the temperature Ta of the image forming apparatus 10. For example, the temperature detection unit 16 detects the temperature around the image forming apparatus 10 as the temperature Ta. The temperature detection unit 16 outputs information on the temperature Ta to the control device 18.

  An example of the control device 18 is a computer. The control device 18 includes a control unit 50 and a storage device 52.

  The control unit 50 governs overall control of the image forming apparatus 10. An example of the control unit 50 is a processor such as a CPU (Central Processing Unit). The control unit 50 is connected to the charging power source 34, the development power source 36, the current detection unit 42, and the temperature detection unit 16 so as to communicate information. The control unit 50 controls the magnitude of the high voltage applied by the high voltage power supply unit 14 to the charging roller 22 and the developing unit 24, the application timing of the voltage, and the like. For example, the control unit 50 performs charging that flows to the charging roller 22 from the detection current Is acquired in a state where the charging power source 34 and the development power source 36 are controlled based on a detection voltage ΔV that is an example of a predetermined voltage. Calculate the current.

  The control unit 50 includes an acquisition unit 54 and a processing unit 56. The control unit 50 functions as the acquisition unit 54 and the processing unit 56 by reading a program such as main operation processing. Part or all of the acquisition unit 54 and the processing unit 56 may be configured by hardware such as a circuit.

  The acquisition unit 54 acquires information such as parameters necessary for execution of the program, and outputs the information to the processing unit 56 or stores it in the storage device 52. For example, the acquisition unit 54 acquires the detection current Is from the current detection unit 42. The acquisition unit 54 acquires the preset detection voltage ΔV, the breakdown voltage of the constant voltage elements 38 and 40, and the resistance R of the resistance member 44 from the storage device 52. The acquisition unit 54 acquires the temperature Ta from the temperature detection unit 16.

  The processing unit 56 executes each process of the program such as the main operation process based on the information. For example, the processing unit 56 sets PWM signals Sa and Sb to be output to the charging power source 34 and the developing power source 36, controls the voltages output from the charging power source 34 and the developing power source 36, and executes printing or the like. Specifically, the processing unit 56 outputs a PWM signal Sa having a duty ratio corresponding to the charging voltage VC applied to the charging roller 22 to the charging power supply 34. The processing unit 56 outputs a PWM signal Sb having a duty ratio corresponding to the developing voltage VDV applied to the developing roller 32 to the developing power source 36.

  The storage device 52 stores a program and parameters necessary for executing the program. For example, the storage device 52 stores a program for executing main operation processing including execution of printing and an adjustment mode for printing.

  FIG. 2 is a configuration diagram illustrating current and voltage in the image forming apparatus 10.

  As illustrated in FIG. 2, when the development power supply 36 acquires the PWM signal Sb from the processing unit 56, the development power supply 36 applies a development voltage VDV to the development roller 32. As a result, the development current IX flows from the development power source 36 to the development roller 32. When the charging power supply 34 acquires the PWM signal Sa from the processing unit 56, the charging power supply 34 applies the charging voltage VC to the charging roller 22. As a result, the charging current IC flows to the charging roller 22.

  The first constant voltage element 38 maintains the potential difference between the regulation voltage VBL applied to the regulation blade 30 and the supply voltage VR applied to the supply roller 28 at the breakdown voltage ΔVZ1 of the Zener diode.

  The second constant voltage element 40 maintains the potential difference between the developing voltage VDV applied to the developing roller 32 and the regulating voltage VBL applied to the regulating blade 30 at the breakdown voltage ΔVZ2 of the Zener diode. As a result, the regulation current IBL flows to the regulation blade 30.

  The first constant voltage element 38 and the second constant voltage element 40 have a potential difference between the development voltage VDV applied to the development roller 32 and the supply voltage VR applied to the supply roller 28, as a breakdown voltage ΔVZ 1 and a breakdown voltage ΔVZ 2. Keep the sum (= ΔVZ1 + ΔVZ2). As a result, the supply current IR flows to the supply roller 28. Further, a sum current IDV (= IX + IBL + IR) of the development current IX, the supply current IR, and the regulation current IBL flows to the development roller 32.

  The processor 56 maintains the potential difference between the charging voltage VC and the development voltage VDV at the detection voltage ΔV when calculating the charging current IC in order to calculate the film thickness of the photoconductor 20 and the like. That is, the processing unit 56 sets the PWM signals Sa and Sb in which the potential difference between the charging voltage VC and the developing voltage VDV becomes the detection voltage ΔV, and outputs the PWM signals Sa and Sb to the charging power source 34 and the developing power source 36. When the detection voltage ΔV is applied to the resistance member 44 having the resistance R, the resistance current Ia flows through the resistance member 44. The current detection unit 42 detects a detection current Is that is the sum (= IC + Ia) of the charging current IC and the resistance current Ia flowing through the resistance member 44. The acquisition unit 54 acquires the detection current Is from the current detection unit 42 and outputs the detection current Is to the processing unit 56. Here, the processing unit 56 detects the detection voltage ΔV which is a potential difference between the charging voltage VC and the supply voltage VR and is maintained constant, the breakdown voltages ΔVZ1 and ΔVZ2 of the constant voltage elements 38 and 40, and the resistance of the resistance member 44. The resistance current Ia is calculated from R. The processing unit 56 calculates the charging current IC by subtracting the resistance current Ia from the detection current Is detected by the current detection unit 42.

  FIG. 3 is a flowchart of main operation processing of the image forming apparatus 10 by the control unit 50. When the power is turned on, the control unit 50 reads the main operation processing program and executes the main operation processing.

  As shown in FIG. 3, in the main operation process, an adjustment mode for adjusting parameters and the like required for printing is executed (S100). For example, the control unit 50 executes process control for setting parameters for maintaining image quality in printing in the normal adjustment mode. Further, the control unit 50 calculates a charging current and calculates a film thickness by executing a film thickness calculation process described later based on the detected current acquired in the adjustment mode.

  Next, the controller 50 determines whether a predetermined number of sheets have been printed or whether a predetermined temperature change has occurred (S102). An example of the predetermined number is several to several tens. When the predetermined number of sheets have been printed or when there has been a predetermined temperature change, the control unit 50 returns to step S100 and executes the adjustment mode (S102: Yes).

  When the predetermined number of sheets has not been printed and there is no predetermined temperature change (S102: No), the control unit 50 executes printing (S104). The control unit 50 determines whether printing has been completed (S106). If the control unit 50 determines that the printing has not been completed (S106: No), the control unit 50 repeats Step S102 and the subsequent steps.

  When the control unit 50 determines that the printing is finished (S106: Yes), the control unit 50 determines whether the power is OFF (S108). When the control unit 50 determines that the power is not OFF (S108: No), the control unit 50 repeats the steps after step S102. On the other hand, if the control part 50 determines with a power supply being OFF (S108: Yes), it will complete | finish a main driving | operation process.

  FIG. 4 is a flowchart of the film thickness calculation process executed by the control unit 50 in the adjustment mode. FIG. 5 is a configuration diagram illustrating the relationship between current and voltage and time in each member in the film thickness calculation process. FIG. 5 is a graph showing, in order from the top, the charging voltage VC, the developing voltage VDV, the supply voltage VR, the detection current Is (= IC + Ia) detected by the current detection unit 42, and the relationship between the charging current IC and time. . In the three graphs from the top, the horizontal axis indicates time, and the vertical axis indicates voltage. In the lower two graphs, the horizontal axis indicates time, and the vertical axis indicates current. The controller 50 executes the film thickness calculation process by reading the film thickness calculation process program stored in the storage device 52 or the main operation process program including the film thickness calculation process program.

  As shown in FIG. 4, in the film thickness calculation process, the acquisition unit 54 acquires and sets the detection voltage ΔV stored in the storage device 52 (S202). An example of the detection voltage ΔV is 850V. The acquisition unit 54 outputs the detection voltage ΔV to the processing unit 56.

  The processing unit 56 outputs a PWM signal Sa having a duty ratio that is a predetermined charging voltage VC <b> 1 to the charging power supply 34. Thereby, the charging power source 34 outputs and applies the charging voltage VC1 to the charging roller 22 (S204). An example of the charging voltage VC1 is −900V. As shown in FIG. 5, the state in which the charging voltage VC1 is maintained is defined as the first adjustment.

The processing unit 56 outputs a PWM signal Sb having a duty ratio that becomes the development voltage VDV1 to the development power source 36. Here, the processing unit 56 sets the developing voltage VDV1 to be a difference between the charging voltage VC1 and the detection voltage ΔV. That is, the development voltage VDV1 satisfies the following expression (1).
VDV1 = VC1−ΔV (1)
An example of the developing voltage VDV1 is −50V. When the developing power supply 36 acquires the PWM signal Sb, the developing power supply 36 outputs and applies the developing voltage VDV1 to the developing roller 32 (S206).

The acquisition unit 54 acquires the detection current Is1 detected by the current detection unit 42 (S208). Here, the detection current Is1 is the sum of the charging current IC1 flowing through the charging roller 22 and the resistance current Ia flowing through the resistance member 44. Therefore, the detection current Is1 satisfies the following expression (2).
Is1 = IC1 + Ia (2)
Here, the breakdown voltage ΔVZ1 of the first constant voltage element 38 is 50V. The breakdown voltage ΔVZ2 of the second constant voltage element 40 is 200V. In this case, the sum of the breakdown voltages ΔVZ1 and ΔVZ2 (= ΔVZ1 + ΔVZ2) is 250V. Under this condition and when the charging voltage VC1 and the development voltage VDV1 are the above-described conditions, the supply voltage VR1 applied to the supply roller 28 is −300V. The detection current Is1 detected by the current detection unit 42 in the first adjustment of this condition is set to −210 μA. The acquisition unit 54 outputs the detection current Is1 to the processing unit 56.

The processing unit 56 calculates the charging current IC1 from the acquired detection current Is1 (S210). Specifically, the processing unit 56 calculates the resistance current Ia based on the following formula (3). The resistance R is 3 MΩ.
Ia = (ΔV−ΔVZ2−ΔVZ1) / R (3)
The processing unit 56 calculates the charging current IC1 from the expressions (2) and (3). In the case of the above-described conditions, the processing unit 56 calculates the resistance current Ia as −200 μA and calculates the charging current IC1 as −10 μA. The processing unit 56 stores the calculated charging current IC1 in the storage device 52 (S212).

  The processing unit 56 outputs a PWM signal Sa having a duty ratio that becomes a predetermined charging voltage VC <b> 2 to the charging power supply 34. Thereby, the charging power supply 34 outputs and applies the charging voltage VC2 to the charging roller 22 (S214). An example of the charging voltage VC2 is -1200V. As shown in FIG. 5, the state in which the charging voltage VC2 is maintained is defined as the second adjustment.

The processing unit 56 outputs a PWM signal Sb having a duty ratio that becomes the development voltage VDV <b> 2 to the development power source 36. Here, the processing unit 56 sets the development voltage VDV2 to be a difference between the charging voltage VC2 and the detection voltage ΔV. That is, the development voltage VDV2 satisfies the following expression (4).
VDV2 = VC2-ΔV (4)
An example of the developing voltage VDV2 is −350V. When acquiring the PWM signal Sb, the developing power source 36 outputs and applies the developing voltage VDV2 to the developing roller 32 (S216).

The acquisition unit 54 acquires the detection current Is2 detected by the current detection unit 42 (S218). The detection current Is2 detected by the current detection unit 42 in the second adjustment is set to −230 μA. Here, the detection current Is2 is the sum of the charging current IC2 flowing through the charging roller 22 and the resistance current Ia flowing through the resistance member 44. Therefore, the detection current Is2 satisfies the following equation (5). The acquisition unit 54 outputs the detection current Is2 to the processing unit 56.
Is2 = IC2 + Ia (5)

  The processing unit 56 calculates the charging current IC2 from the acquired detection current Is2 (S220). Specifically, the processing unit 56 calculates the charging current IC2 as −30 μA from the resistance current Ia calculated based on the above equation (3), the supply voltage VR2 of −600 V, and the equation (5). The processing unit 56 stores the calculated charging current IC2 in the storage device 52 (S222).

  The processing unit 56 stops outputting the PWM signals Sa and Sb (S224). As a result, the charging power supply 34 stops applying the charging voltage VC to the charging roller 22. The development power source 36 stops applying the development voltage VDV to the development roller 32. In other words, the voltage applied to the charging roller 22 and the developing roller 32 is 0V.

The processing unit 56 calculates the inclination GR based on the charging voltage VC1, the charging current IC1, the charging voltage VC2, and the charging current IC2 (S226). FIG. 6 is a graph illustrating a method for calculating the slope GR of the charging current IC with respect to the charging voltage VC by the processing unit 56. As illustrated in FIG. 6, the processing unit 56 calculates the gradient GR based on the following equation (6).
GR = (IC2-IC1) / (VC2-VC1) (6)
Under the above conditions, the processing unit 56 calculates the slope GR as 0.067.

  The processing unit 56 calculates and sets the film thickness Tc of the photoconductor 20 corresponding to the inclination GR (S228). FIG. 7 is a graph illustrating the relationship between the slope GR of the charging current IC with respect to the charging voltage VC and the film thickness Tc of the photoconductor 20. As shown in the graph shown in FIG. 7 described in Japanese Patent Application Laid-Open No. 2004-334063, the slope GR of the charging current IC with respect to the charging voltage VC is related to the film thickness Tc of the photoconductor 20. That is, the inclination GR differs for each film thickness Tc. Accordingly, the processing unit 56 can extract and set the film thickness Tc corresponding to the calculated gradient GR. For example, the processing unit 56 may extract the film thickness Tc corresponding to the calculated inclination GR based on the film thickness table including the film thickness Tc associated with the inclination GR stored in the storage device 52 in advance. .

  Thereby, the process part 56 complete | finishes a film thickness calculation process. The processing unit 56 controls the charging voltage VC and the like based on the film thickness Tc. For example, as illustrated in FIG. 7, the processing unit 56 controls the charging voltage VC while adjusting the charging voltage VC based on the inclination GR set from the film thickness Tc and the starting voltage when the charging voltage VC is applied.

  As described above, in the image forming apparatus 10, the control unit 50 maintains the detection current Is detected by the current detection unit 42 in a state where the potential difference between the charging power supply 34 and the development power supply 36 is maintained at the detection voltage ΔV. get. Thereby, the control unit 50 can accurately calculate the resistance current Ia included in the detection current Is. As a result, the control unit 50 can accurately calculate the charging current IC flowing through the charging roller 22 based on the detection current Is and the resistance current Ia.

Second Embodiment
Next, a second embodiment in which a part of the above-described embodiment is changed will be described.

  FIG. 8 is a diagram illustrating the voltage Vz and current Iz of the Zener diode ZD that constitutes the constant voltage elements 38 and 40. As shown in FIG. 8, it is assumed that the voltage Vz is applied to the Zener diode ZD and the current Iz flows.

  FIG. 9 is a graph showing the relationship between the voltage Vz and current Iz of the Zener diode ZD and the temperature Ta. As shown in FIG. 9, even if the same current Ib flows in the reverse direction, the breakdown voltage of the Zener diode ZD differs when the temperature Ta is different. Therefore, it can be seen that the accuracy can be further improved by correcting the breakdown voltage of the Zener diode ZD to any of the correction amounts Vza, Vzb, Vzc based on the temperature Ta. Therefore, the control unit 50 of the present embodiment calculates the charging current IC from the detection current Is based on the voltage corresponding to the temperature Ta of the first constant voltage element 38 and the second constant voltage element 40 that are Zener diodes.

  FIG. 10 is a flowchart of the film thickness calculation process executed by the control unit 50. As shown in FIG. 10, in the film thickness calculation process, first, the control unit 50 executes a correction value determination process (S200).

  FIG. 11 is an example of the correction table 58 used in the correction value determination process. The storage device 52 stores a correction table 58 shown in FIG. The correction table 58 associates the temperature Ta with correction amounts Vza, Vzb, and Vzc for correcting the voltage of the Zener diode ZD. The correction amounts Vza, Vzb, Vzc may be a difference from a reference voltage, or may be an absolute value of a voltage with 0 V as a reference (that is, a potential difference between both ends of the Zener diode ZD). The control unit 50 extracts correction amounts Vza, Vzb, and Vzc corresponding to the temperature Ta acquired from the temperature detection unit 16, and determines the correction values VA.

  FIG. 12 is a flowchart of the correction value determination process executed by the control unit 50.

  As illustrated in FIG. 12, the acquisition unit 54 acquires information on the temperature Ta from the temperature detection unit 16 and outputs the information to the processing unit 56 (S304). The processing unit 56 determines whether or not the acquired temperature Ta is normal temperature (S306). The processing unit 56 determines that the temperature Ta is normal if the temperature Ta is a predetermined temperature for normal temperature determination (eg, about 25 ° C. or 20 ° C. to 26 ° C.). If the processing unit 56 determines that the temperature Ta is normal temperature (S306: Yes), the normal temperature correction amount Vzb extracted from the correction table 58 is set as the correction value VA (S308), and the step of film thickness calculation processing is performed. S202 and subsequent steps are executed.

  When determining that the temperature Ta is not normal temperature (S306: No), the processing unit 56 determines whether the temperature Ta is low (S310). The processing unit 56 determines that the temperature Ta is low if the temperature Ta is a predetermined low-temperature determination temperature (for example, about 15 ° C. or 20 ° C. or less). If the processing unit 56 determines that the temperature Ta is a low temperature (S310: Yes), the low temperature correction amount Vza extracted from the correction table 58 is set as the correction value VA (S312), and the step of the film thickness calculation process S202 and subsequent steps are executed.

  When determining that the temperature Ta is not low (S310: No), the processing unit 56 determines whether the temperature Ta is high (S314). The processing unit 56 determines that the temperature Ta is high if the temperature Ta is a predetermined high temperature determination temperature (for example, about 27 ° C. or 26 ° C. to 35 ° C.). If the processing unit 56 determines that the temperature Ta is high (S314: Yes), the high temperature correction amount Vzc extracted from the correction table 58 is set as the correction value VA (S316), and the step of film thickness calculation processing is performed. S202 and subsequent steps are executed.

  When the temperature Ta is extremely low or very high, the processing unit 56 determines that the temperature Ta is not high (S314: No), executes the interruption process, and ends.

  Thereafter, the processing unit 56 executes step S202 and subsequent steps of the film thickness calculation process based on the determined correction value VA. For example, in steps S210 and S220, the processing unit 56 substitutes the correction value VA for the breakdown voltage ΔVZ1 and the breakdown voltage ΔVZ2, and calculates the resistance current Ia based on Expression (3).

  As described above, in the image forming apparatus 10 according to the second embodiment, the control unit 50 corrects the breakdown voltages ΔVZ1 and ΔVZ2 of the constant voltage elements 38 and 40 based on the temperature Ta. The accuracy of the current IC can be further improved.

  The main operation processing program including the adjustment mode program executed by the image forming apparatus 10 of the present embodiment is a file in an installable format or an executable format, and is a CD-ROM, a flexible disk (FD), a CD-R. And recorded on a computer-readable recording medium such as a DVD (Digital Versatile Disk).

  Further, the main operation processing program executed by the image forming apparatus 10 of the present embodiment may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. good. The main operation processing program executed by the image forming apparatus 10 of the present embodiment may be provided or distributed via a network such as the Internet.

  Moreover, you may comprise so that the program of the main operation processing of this embodiment may be provided by previously incorporating in ROM etc.

  The main operation processing program executed by the image forming apparatus 10 of the present embodiment has a module configuration including the above-described units (acquisition unit 54, processing unit 56), and CPU (processor) as actual hardware. Reads out the main operation processing program from the storage medium and executes it to load the respective units onto the main storage device, and the acquisition unit 54 and the processing unit 56 are generated on the main storage device.

  The image forming apparatus 10 of the present embodiment may be applied to an apparatus having at least one or more functions among a copy function, a printer function, a scanner function, and a facsimile function.

  The function, connection relationship, number, and the like of the configuration of each embodiment described above may be changed as appropriate. Each embodiment mentioned above may be combined suitably. You may change suitably the order of the step of the flowchart mentioned above.

  The above-described embodiments have been presented by way of example and are not intended to limit the scope of the present invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. The embodiments and modifications of the embodiments are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus 12 ... Image forming part 14 ... High voltage power supply part 16 ... Temperature detection part 18 ... Control apparatus 20 ... Photoconductor 22 ... Charging roller 24 ... Developing unit 26 ... Transfer roller 28 ... Supply roller 30 ... Restricting blade 32 ... Developing roller 34 ... Charging power source 36 ... Developing power source 38 ... First constant voltage element 40 ... Second constant voltage element 42 ... Current detection unit 44 ... Resistance member 50 ... Control unit 54 ... Acquisition unit 56 ... Processing unit

JP 2004-334063 A JP 2000-089624 A Japanese Patent Laying-Open No. 2015-52760

Claims (6)

An image carrier on which an electrostatic latent image is formed;
A charging unit for charging the image carrier;
A developing section for supplying a developer to the image carrier on which the electrostatic latent image is formed;
A charging power source for applying a voltage to the charging unit;
A developing power source for applying a voltage to the developing unit;
A constant voltage member connected to the developing power source and maintaining both ends at a constant voltage;
A resistance member having one end connected to the charging power source and the other end connected to the developing power source via the constant voltage member;
A current detection unit for detecting a detection current including a charging current flowing through the charging unit;
A control unit that calculates a charging current flowing through the charging unit based on the detection current acquired in a state where the charging power source and the development power source are controlled based on a predetermined voltage;
An image forming apparatus comprising: The image forming apparatus according to claim 1, wherein the control unit calculates the charging current based on the detected current acquired in an adjustment mode for adjusting a parameter required for printing.   The image forming apparatus according to claim 1, wherein the constant voltage member includes a Zener diode connected between the developing power source and the resistance member. A temperature detector for detecting the temperature of the image forming apparatus;
The image forming apparatus according to claim 3, wherein the control unit calculates the charging current from the detection current based on a voltage of the Zener diode corresponding to the temperature. An image carrier on which an electrostatic latent image is formed;
A charging unit for charging the image carrier;
A developing section for supplying a developer to the image carrier on which the electrostatic latent image is formed;
A charging power source for applying a voltage to the charging unit;
A developing power source for applying a voltage to the developing unit;
A constant voltage member connected to the developing power source and maintaining both ends at a constant voltage;
A resistance member having one end connected to the charging power source and the other end connected to the developing power source via the constant voltage member;
A current detection unit for detecting a detection current including a charging current flowing through the charging unit;
A method for calculating a charging current in an image forming apparatus comprising:
Based on a predetermined voltage, obtain the detection current obtained in a state of controlling the charging power supply and the development power supply,
A charging current calculation method for calculating a charging current flowing through the charging unit from the detection current. An image carrier on which an electrostatic latent image is formed;
A charging unit for charging the image carrier;
A developing section for supplying a developer to the image carrier on which the electrostatic latent image is formed;
A charging power source for applying a voltage to the charging unit;
A developing power source for applying a voltage to the developing unit;
A constant voltage member connected to the developing power source and maintaining both ends at a constant voltage;
A resistance member having one end connected to the charging power source and the other end connected to the developing power source via the constant voltage member;
A current detection unit for detecting a detection current including a charging current flowing through the charging unit;
An acquisition unit that acquires the detection current acquired in a state where the charging power source and the development power source are controlled based on a predetermined voltage on a computer provided in the image forming apparatus,
A program that functions as a calculation unit that calculates a charging current flowing through the charging unit from the detection current.

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