JP2015079108A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that enables a user or a service person to recognize the mounting state of a cartridge member used for image formation quicker than before.SOLUTION: An image forming apparatus includes a detachable cartridge member 1 that is used for image formation, a high voltage power source 206 that supplies an output voltage to the cartridge member 1, an output voltage detection unit 205 that detects the voltage value of the output voltage, and a CPU 201. The CPU 201 controls an output power source so that the voltage value of the output voltage becomes equal to a reference voltage value for the cartridge member 1 to perform normal operation. The image forming apparatus determines the mounting state of the cartridge member 1 on the basis of the voltage value of the output voltage before becoming equal to the reference voltage value.

Description

  The present invention relates to a power saving technique for an image forming apparatus such as a copier or a multifunction peripheral.

  In an image forming apparatus such as an electrophotographic copying machine or printer, it is known that durability deterioration of an image forming unit including an image carrier such as a photosensitive drum affects an image to be formed. For this purpose, a cartridge-type image forming unit is used so that a user or a serviceman can easily replace the image forming unit. However, in an image forming apparatus using a cartridge type image forming unit, the image forming unit may not be mounted correctly. In a state where the image forming unit is not properly mounted, the drive transmission for rotationally driving the image carrier and the contact failure of the high voltage contact for charging the surface of the image carrier occur. Such a state causes image defects. Therefore, it is necessary to confirm that the image forming unit is correctly mounted.

  Japanese Patent Application Laid-Open No. H10-228561 discloses that when a high voltage is applied to the image carrier, the image forming unit is correctly mounted according to the amount of current when a voltage is applied to a load such as a charging member that charges the image carrier. An invention to confirm is disclosed.

JP-A-6-3891

  Conventionally, after a voltage is applied to a load, the current amount is detected after the state is stabilized, and the mounting state of the image forming unit is confirmed. Therefore, it takes time to stabilize the state. 2. Description of the Related Art In recent years, in order to suppress power consumption, an image forming apparatus is becoming a mainstream configuration in which a sleep job is quickly entered after an image forming process is completed and a print job is quickly returned. In such a configuration, it is necessary to quickly check the mounting state of the cartridge type image forming unit in order to reduce the return time. The same applies to other cartridge-type replaceable members (hereinafter referred to as “cartridge members”) other than the image forming unit.

  In order to solve the above problems, it is a main object of the present invention to provide an image forming apparatus capable of quickly confirming a mounting state of members used for image formation.

  An image forming apparatus of the present invention that solves the above problems includes a detachable cartridge member used for image formation, a power source that supplies a voltage to the cartridge member, a voltage detector that detects a voltage value of the voltage, Based on the constant voltage control means for controlling the power supply so that the voltage value of the voltage becomes the reference voltage value, and the voltage value before the reference voltage value detected by the voltage detection unit, the cartridge member And determining means for determining the wearing state.

  According to the present invention, since the mounting state of the cartridge member is determined before the voltage supplied to the cartridge member becomes equal to the reference voltage value, the mounting state of the cartridge member can be confirmed more quickly than before.

1 is a schematic configuration diagram of an image forming apparatus. FIG. 3 is a circuit configuration diagram of a cartridge detection circuit according to the first embodiment. The figure showing the difference of the time change of output voltage. 3 is a flowchart showing the overall operation of the image forming apparatus. 10 is a flowchart of a confirmation process of a cartridge member mounting state. Explanatory drawing of time until the voltage value of an output voltage becomes a threshold value. The circuit block diagram of the cartridge detection circuit of 3rd Embodiment. The circuit block diagram of the cartridge detection circuit of 4th Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<First Embodiment>
FIG. 1 is a schematic configuration diagram of a tandem color image forming apparatus.
The image forming apparatus includes an image forming unit 1Y that forms a yellow image, an image forming unit 1M that forms a magenta image, an image forming unit 1C that forms a cyan image, and an image forming unit 1Bk that forms a black image. Four image forming units are provided. These four image forming units 1Y, 1M, 1C, and 1Bk are arranged in a line at regular intervals.

  The configuration of the image forming unit 1Y will be described. Since the image forming units 1M, 1C, and 1Bk have the same configuration as the image forming unit 1Y, description thereof is omitted. The image forming unit 1Y includes a drum-type electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 2a as an image carrier. The image forming unit 1Y includes a primary charger 3a, a developing device 4a, a transfer roller 5a, and a drum cleaner 6a around the photosensitive drum 2a. The image forming unit 1Y is an example of a cartridge member in which the photosensitive drum 2a, the primary charger 3a, the developing unit 4a, the transfer roller 5a, and the drum cleaner 6a are integrated, and is detachable from the image forming apparatus. The cartridge member is a member that can be attached to and detached from an image forming apparatus used for image formation.

  The photosensitive drum 2a is a negatively charged OPC photosensitive member having a photoconductive layer on an aluminum drum base, and is rotationally driven at a predetermined process speed by a driving device (not shown). The primary charger 3a uniformly charges the surface of the photosensitive drum 2a to a predetermined negative potential with a charging bias.

  The laser exposure unit 7 installed below the primary charger 3a and the developing unit 4a includes a laser emission unit that emits light corresponding to image data, a polygon lens, a reflection mirror, and the like. The laser exposure unit 7 exposes the photosensitive drums 2a, 2b, 2c, and 2d to form electrostatic latent images of respective colors according to image data on the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d. . The developing devices 4a, 4b, 4c, and 4d store yellow toner, cyan toner, magenta toner, and black toner, respectively. The toner images are developed (visualized) by attaching each color toner to the electrostatic latent images formed on the respective photosensitive drums 2a, 2b, 2c, and 2d.

  The transfer roller 5a is disposed so as to be in contact with the photosensitive drum 2a via the intermediate transfer belt 8 in the primary transfer portion 32a. The toner images on the photosensitive drums 2a, 2b, 2c, and 2d are sequentially transferred onto the intermediate transfer belt 8 in a superimposed manner. The drum cleaners 6a, 6b, 6c, and 6d are configured by a cleaning blade or the like, and scrape off and remove the transfer residual toner remaining on the photosensitive drums 2a, 2b, 2c, and 2d after the primary transfer.

  The intermediate transfer belt 8 is arranged on the upper surface side of the photosensitive drums 2 a, 2 b, 2 c, 2 d and is stretched by the secondary transfer counter roller 10, the tension roller 11, and the intermediate transfer drive roller 13. The intermediate transfer belt 8 is made of a dielectric resin such as a polycarbonate, a polyethylene terephthalate resin film, a polyvinylidene fluoride resin film, or the like. The secondary transfer counter roller 10 is disposed in the secondary transfer portion 34 so as to be in contact with the secondary transfer roller 12 via the intermediate transfer belt 8. The image formed on the intermediate transfer belt 8 is conveyed from the paper feeding unit 17 and transferred to a recording medium P such as paper in the secondary transfer unit 34.

  The recording medium P is stored in a paper feeding unit 17 disposed below the image forming units 1Y, 1M, 1C, and 1Bk, and is conveyed to the secondary transfer unit 34 via the conveyance path 18 by the conveyance roller 19. . The recording medium P onto which the image has been transferred by the secondary transfer unit 34 is then fixed by the fixing unit 16 and discharged from the image forming apparatus by the discharge roller 21.

<Cartridge detection circuit>
FIG. 2 is a circuit configuration diagram of a cartridge detection circuit for detecting the presence / absence of the image forming units 1Y, 1M, 1C, and 1Bk. The cartridge detection circuit detects “present” when the image forming units 1Y, 1M, 1C, and 1Bk are correctly installed, and “none” when the image forming units 1Y, 1M, 1C, and 1Bk are properly installed. In the following description, the image forming units 1Y, 1M, 1C, and 1Bk are referred to as the cartridge member 1.
The cartridge detection circuit includes a CPU (Central Processing Unit) 201, an AD converter 203, and a high voltage power source 206. The high voltage power source 206 supplies a high voltage output voltage for contact charging the photosensitive drum 2 to the primary charger 3 in the cartridge member 1. The high voltage power supply 206 supplies an output voltage by driving the high voltage output unit 204 according to a drive signal from the CPU 201.

  The CPU 201 outputs a 50 [KHz] PWM (Pulse Width Modulation) signal as a drive signal. The voltage value of the output voltage changes depending on the ON ratio of the PWM signal. The voltage value of the output voltage is converted into a detection voltage value of 0 to 3.3 [V] by the output voltage detection unit 205, and 10-bit digital data (AD value) of “000h” to “3FFh” in the AD converter 203. Detected as In the present embodiment, the relationship between the voltage value of the output voltage, the detected voltage value, and the AD value is such that when the voltage value of the output voltage is “−1000 [V]”, the detected voltage value is “0.3 [V]”. , The AD value is “05Ch”. When the voltage value of the output voltage is “0 [V]”, the detected voltage value is “2.8 [V]”, and the AD value is “368h”.

  The CPU 201 performs constant voltage control by performing feedback control so that the voltage value of the output voltage becomes equal to the target value of the output voltage. The “target value” is a reference voltage value for the cartridge member 1 to perform normal operation.

FIG. 3 is a diagram illustrating the difference in the time change of the output voltage depending on the presence or absence of the cartridge member 1.
FIG. 3A shows the rise time of the output voltage. When the cartridge member 1 is not provided, the primary charger 3 is not connected and the connection load is reduced. For this reason, the output voltage rises at a high speed. When the cartridge member 1 is present, the primary charger 3 is connected. In this case, the connection load increases, and the rise of the output voltage is delayed as compared with the case where there is no cartridge member 1 due to the current flowing through the primary charger 3 and the charging of the capacity component of the primary charger 3.

When the rising time when there is no cartridge member 1 is Ta and the rising time when there is the cartridge member is Tb, the relationship is Tb> Ta.
In the present embodiment, the presence or absence of the cartridge member 1 is detected based on the difference in the rise time. Therefore, it is possible to determine the presence or absence of the cartridge member 1 before the output voltage reaches the target value and stabilizes.

In this embodiment, Ta = 10 [ms] and Tb = 35 [ms]. The CPU 201 determines whether or not the cartridge member 1 is present, for example, 5 [ms] after the start of supply of the output voltage. FIG. 3B shows the voltage value of the output voltage after 5 [ms] from the start of supply of the output voltage.
The voltage value of the output voltage after 5 [ms] from the start of supply of the output voltage is “−300 [V]” when the cartridge member 1 is not present (at the time of loading / unloading), and “−” when the cartridge member 1 is present (when mounted) 100 [V] ". Therefore, in the present embodiment, an intermediate value “−200 [V]” is set as a threshold value for determining the presence or absence of the cartridge member 1. The CPU 201 holds the threshold value as an AD value after AD conversion detected by the CPU 201. In this embodiment, “2CBh” is set.

  The CPU 201 starts the supply of the output voltage to the high-voltage power supply 206 and starts timing by the timer, detects the voltage value of the output voltage when the timer reaches 5 [ms], and acquires the detected voltage value. The CPU 201 compares the AD value obtained by AD converting the acquired detection voltage value with the threshold value “2CBh”. The CPU 201 determines that the cartridge member 1 is “absent” when the AD value after the elapse of 5 [ms] is less than or equal to the threshold value, and determines that the cartridge member 1 is “present” if the AD value is greater than the threshold value. As described above, the CPU 201 can determine the presence / absence of the cartridge member 1 based on the difference in the temporal change in the voltage value of the output voltage.

FIG. 4 is a flowchart showing the overall operation of the image forming apparatus.
When the image forming apparatus is powered on, the CPU 201 confirms the mounting state of the cartridge member 1 (the presence or absence of the cartridge member 1) (S401). Details of the confirmation process of the mounting state of the cartridge member 1 will be described later.

When the cartridge member 1 is mounted, the CPU 201 performs an adjustment operation of the image forming apparatus (S401: “Yes”, S402). By the adjustment operation of the image forming apparatus, for example, a current value when a constant charging voltage is applied to the photosensitive drum 2 is measured, and an applied voltage for obtaining a predetermined current value is determined. By such adjustment, the image forming conditions of the image forming apparatus can be set optimally.
After completion of the adjustment operation, the image forming apparatus shifts to a standby mode (S403). From the standby mode, the operation mode is shifted according to various conditions. For example, when a print job is instructed to the image forming apparatus, the image forming apparatus shifts to a print mode and performs image forming processing (S404: Y, S405). After the image forming process is completed, the image forming apparatus returns to the standby mode.

  In the standby mode, when the condition for shifting to the sleep mode is satisfied due to elapse of a predetermined time or the like, the image forming apparatus shifts to the sleep mode (S404: N, S406: Y, S407). When a return condition such as a print job instruction occurs during the sleep mode, the image forming apparatus returns from the sleep mode (S408: Y). When returning from the sleep mode, since there is a possibility that the cartridge member 1 has been replaced during the sleep mode, the processing from step S401 onward is performed again, and the process shifts to the standby mode.

  In the standby mode, when the door of the part where the cartridge member 1 is mounted is opened without shifting to the sleep mode, the cartridge member 1 may be replaced. Therefore, after the door is closed, the image forming apparatus performs the processing from step S401 onward in the same manner as when returning from the sleep mode (S406: N, S409: Y, S410: Y, S401). If the door is not opened and closed and the power is turned off in the standby mode, the image forming apparatus stops its operation (S411: Y).

The confirmation process of the mounting state of the cartridge member 1 will be described with reference to the flowchart of FIG.
The CPU 201 starts supplying the output voltage and starts measuring an elapsed time T from the start of supply (S501, S502). The CPU 201 measures the voltage value of the output voltage when the elapsed time T reaches 5 [ms] (S503: Y, S504).

  The CPU 201 compares the detected voltage value V obtained by converting the voltage value of the output voltage with a threshold value “−200 [V]”. Based on the comparison result, the CPU 201 determines whether the cartridge member 1 is mounted (there is a cartridge member), whether it is mounted / removed or not mounted correctly (no cartridge member). If the detected voltage value V is higher than the threshold value, it is determined that there is a cartridge member (S505: Y, S506). If the detected voltage value V is lower than the threshold value, it is determined that there is no cartridge member (S505: N, S507).

  In this way, by determining the presence / absence of the cartridge member 1 based on the elapsed time from the start of supply of the output voltage and the voltage value of the output voltage, as compared with the conventional case where the presence / absence is determined after the output voltage is stabilized. Can be determined at high speed. In the above example, in order to make a determination based on the voltage value after 5 [ms] has elapsed from the start of supply of the output voltage, it is not necessary to wait for determination until 35 [ms] when the output voltage stabilizes, and the time is reduced by 30 [ms]. Is realized.

Second Embodiment
In the second embodiment, the presence or absence of the cartridge member 1 is determined based on the time until the voltage value of the output voltage becomes equal to the threshold value. FIG. 6 is an explanatory diagram of the time until the voltage value of the output voltage reaches the threshold value.

  FIG. 6 illustrates the result of sampling the voltage value of the output voltage until the threshold value “−300 [V]” is reached and measuring the time until the threshold value is exceeded. In the present embodiment, the CPU 201 starts sampling the voltage value of the output voltage at intervals of 0.1 [ms] when the supply of the output voltage is started. In addition, the timer starts timing with the start of output voltage supply. Time measurement is stopped when the voltage value of the output voltage reaches a threshold value, and the elapsed time from the start of supply of the output voltage is acquired.

  In FIG. 6, the elapsed time Tc to the threshold when the cartridge member 1 is not present is 5 [ms], and the elapsed time Td when it is present is 17.5 [ms]. The CPU 201 holds in advance a reference time for determination (in this example, 10 [ms]). If the measured elapsed time is less than the reference time, the CPU 201 determines that there is no cartridge member 1, and if it is equal to or longer than the reference time, the cartridge member. It is determined that 1 is present.

In this way, it is possible to determine the mounting state of the cartridge member 1 based on the elapsed time until the threshold value is reached.
In each of the above embodiments, each numerical value is an example, and the invention is not limited to the numerical value of the embodiment. By determining the output voltage and the threshold value according to the output characteristics of the high-voltage power source 206 and the load of the cartridge member 1, it is possible to determine the mounting state of the cartridge member 1 according to the configuration.

<Third Embodiment>
In the first and second embodiments, the example in which the mounting state (presence / absence) of the cartridge member 1 is determined based on the voltage value of the output voltage has been described. FIG. 7 is a circuit configuration diagram of a cartridge detection circuit for detecting the current value and detecting the presence or absence of the cartridge member 1.

  Compared with the circuit diagram of FIG. 2, the high-voltage power supply 209 is different in that it includes a current detection circuit 207 for current detection. The CPU 201 makes a determination based on the output current value detected by the current detection circuit 207 in the same manner as the determination of the presence or absence of the cartridge member 1 based on the voltage value. In other words, the CPU 201 supplies the output voltage until the output current value reaches the predetermined current value, or the difference in the output current value after the predetermined time has elapsed since the start of the supply of the output voltage, which is caused by the difference in the output current value over time. The presence or absence of the cartridge member 1 is determined based on the time difference from the start.

<Fourth embodiment>
FIG. 8 is a circuit configuration diagram of a cartridge detection circuit that determines the mounting state (presence / absence) of the cartridge member 1 according to the fourth embodiment. In comparison with the circuit diagram of FIG. 2, the configuration of the high-voltage output unit 211 in the high-voltage power supply 210 is different. 2 shows a configuration in which the feedback control of the output voltage is performed by the CPU 201. In FIG. 8, the feedback control of the output voltage is performed in the high-voltage power supply 210.

  The high voltage output unit 211 receives the detection voltage value detected by the output voltage detection unit 205 and the target value output from the CPU 201 with a drive signal (PWM signal) of 50 [KHz] and smoothed by a resistor and a capacitor. The The high voltage output unit 211 performs constant voltage control by controlling the voltage value of the output voltage to be equal to the target value using an operational amplifier.

In the fourth embodiment, the presence or absence of the cartridge member 1 can be determined in the same manner as in the first and second embodiments. Further, by providing the current detection circuit 207 of the third embodiment in the high-voltage power supply 210, the presence or absence of the cartridge member 1 can be determined in the same manner as in the third embodiment.
As described above, various methods may be used for controlling the high-voltage output voltage, and the present embodiment is not limited.

Claims (6)

A removable cartridge member used for image formation;
A power supply for supplying a voltage to the cartridge member;
A voltage detector for detecting a voltage value of the voltage;
Constant voltage control means for controlling the power supply so that the voltage value of the voltage becomes a reference voltage value;
And determining means for determining a mounting state of the cartridge member based on the voltage value before the reference voltage value detected by the voltage detection unit.
Image forming apparatus. The determination means determines the mounting state of the cartridge member based on the voltage value detected after a predetermined time has elapsed since the power supply started supplying the voltage to the cartridge member.
The image forming apparatus according to claim 1. The determination means holds in advance an intermediate value between the voltage value at the time of mounting the cartridge member and the voltage value at the time of mounting / demounting after the predetermined time has elapsed from the start of supply of the voltage. The mounting state of the cartridge member is determined by comparing the voltage value with the intermediate value.
The image forming apparatus according to claim 2. The determination unit is configured so that the voltage value detected by the voltage detection unit from when the power source starts supplying the voltage to the cartridge member until the voltage value reaches a predetermined voltage value different from the reference voltage value. The mounting state of the cartridge member is determined,
The image forming apparatus according to claim 1. The determination unit holds in advance a reference time from the start of supply of the voltage until the voltage value becomes the predetermined voltage value, and the detected voltage value becomes the predetermined voltage value. The mounting state of the cartridge member is determined by comparing the time and the reference time.
The image forming apparatus according to claim 4. Current detection means for detecting a current value generated by the voltage;
The determination means determines the mounting state of the cartridge member based on a time change of the current value before becoming equal to the reference voltage value instead of the voltage value.
The image forming apparatus according to claim 1.

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