JP4996148B2 - Image forming apparatus and control method thereof - Google Patents

Description

  The present invention relates to an image forming apparatus and a control method thereof, and more particularly to an image forming apparatus using an electrophotographic method and a control method thereof.

  In an image forming apparatus using an electrophotographic system, consumables such as toner are used. The toner is stored in a detachable unit such as a toner cartridge. When the toner is consumed, the user removes the toner cartridge from the main body of the image forming apparatus and replenishes the toner, or the toner cartridge is new. The cartridge can be easily replaced.

  In addition, a configuration in which a plurality of electrophotographic process devices such as a developing device and a photosensitive member are built in a single housing to form a unit (hereinafter referred to as a process unit) and can be detached from the main body of the image forming apparatus or pulled out. Many. Since the process unit can be removed from or pulled out from the main body, the maintenance and replacement of the built-in electrophotographic process apparatus can be facilitated, and the workability of the user and service personnel can be improved.

  Generally, these removable units are called customer replaceable units (hereinafter referred to as CRU).

  Recently, these CRUs have built in a nonvolatile memory such as an EEPROM, and various types of information are stored in the nonvolatile memory (see Patent Document 1 and the like).

  For example, in the case of a toner cartridge, information necessary for maintenance such as toner type, toner remaining amount, or usage time is stored in a built-in nonvolatile memory, and the replacement timing of the toner cartridge and the type to be replaced are determined by the user. Can be easily informed. Also, maintenance information is stored not in the image forming apparatus side but in the toner cartridge, so that maintenance information such as remaining toner amount and usage time is newly installed even when the used toner cartridge is installed in another model. It is possible to reliably notify the apparatus.

Further, by storing the identification information of the CRU in the built-in nonvolatile memory, it is possible to identify a regular CRU and a counterfeit product that hinders operation.
JP 2005-151175 A

  Normally, power is supplied to the nonvolatile memory built in the CRU from the main body side of the image forming apparatus, and information writing and reading are controlled from the main body side of the image forming apparatus.

  Information stored in the nonvolatile memory is maintenance information, identification information, and the like as described above, and the frequency of writing and reading of information is generally not so high.

  For this reason, conventionally, writing and reading with respect to the nonvolatile memory are often performed at an arbitrary timing on the main body side of the image forming apparatus without recognizing the state of the CRU. For example, there is a method of performing writing and reading with respect to the nonvolatile memory at predetermined time intervals.

  On the other hand, when the user removes the CRU, the timing of writing or reading on the image forming apparatus side is usually unknown. For this reason, for example, the user may remove the CRU while the image forming apparatus is accessing the nonvolatile memory in a standby state or the like. When such a situation occurs, information to be written is not normally written to the nonvolatile memory, or incorrect information is written to the nonvolatile memory.

  The present invention has been made in view of the above circumstances, and even when a CRU is attempted to be attached to or detached from the nonvolatile memory built in the CRU while being energized, information can be reliably written. An object of the present invention is to provide an image forming apparatus and a control method thereof.

In order to solve the above problems, an image forming apparatus according to the present invention includes a replaceable unit having a nonvolatile memory, a cover that opens and closes when the replaceable unit is replaced, and a detection unit that detects opening and closing of the cover A first power supply that outputs a first power supply voltage; a second power supply that steps down the first power supply voltage to convert it to a second power supply voltage and supplies power to the nonvolatile memory; A voltage detection unit that detects the first power supply voltage, and when the detection unit detects that the cover is opened, or is detected by the voltage detection unit when the first power supply is turned off. When the first power supply voltage drops below a predetermined threshold, the output voltage of the first power supply drops from the predetermined threshold voltage to a limit voltage that can generate the second power supply voltage. during the voltage drop time, before And a control unit for writing the predetermined data to the nonvolatile memory, wherein the control unit, when the predetermined data writing is not completed during the voltage drop time, write error with the predetermined data When the flag is set in the non-volatile memory and the write error flag is set when the non-volatile memory is read, the predetermined data is written again in the non-volatile memory .

  According to the image forming apparatus and the control method therefor according to the present invention, even when the CRU is to be attached to or detached from the nonvolatile memory built in the CRU, reading and writing of information are ensured. It can be carried out.

  An image forming apparatus 1 and a control method thereof according to an embodiment of the present invention will be described with reference to the accompanying drawings.

(1) Configuration FIG. 1 is a diagram illustrating a configuration example of an image forming apparatus 1. The configuration example shown in FIG. 1 shows a configuration that is particularly relevant to the present invention. The image forming apparatus 1 includes, for example, a scanner unit that reads a document, an image processing unit that performs various image processing, a paper feeding unit that conveys recording paper, and a paper discharge unit that conveys printed recording paper to the outside. However, illustration of these is omitted.

  The image forming apparatus 1 includes, for example, a process unit 2 and a toner cartridge 3 as units (CRU) that can be replaced by a user or a service person.

  The process unit 2 includes a photosensitive drum 21 at the center, and a charging device 22, an exposure device 23, a developing device 24, a cleaner 25, and the like are disposed around the photosensitive drum 21.

  After the surface of the photosensitive drum 21 is charged to a predetermined potential by the charging device 22, an electrostatic latent image is formed on the photosensitive drum 21 by light such as laser light emitted from the exposure device 23. This electrostatic latent image is developed with toner built in the developing device 24, and a toner image is formed on the surface of the photosensitive drum 21. The toner image is transferred to the recording paper 12 by the transfer roller 11 and fixed to the recording paper 12 by a fixing device (not shown).

  The process unit 2 is unitized from the standpoint of maintainability and the like. For example, the process unit 2 is configured to be replaceable by opening the cover 2a provided on the front surface of the image forming apparatus 1. The cover 2a is provided with a cover open / close detection switch 2b for detecting the open / closed state of the cover 2a.

  The process unit 2 includes a nonvolatile memory 26 such as an EEPROM (Electronically Erasable and Programmable Read Only Memory).

  In the nonvolatile memory 26, for example, a product type name, a serial number, a manufacturer, and the like are recorded as identification information for identifying the process unit 2. The process unit 2 records the usage time, the number of sheets passed, time information, etc. as information about the usage time.

  On the other hand, the toner cartridge 3 is a unit containing toner, and the toner cartridge 31 is also configured as a replaceable unit (CRU). The toner cartridge 3 also has a built-in nonvolatile memory 31, and as identification information, for example, the type and manufacturer of the toner are recorded, and as information regarding the usage time, for example, the use start time is recorded, Information such as the remaining amount of toner is recorded.

  Similarly to the process unit 2, the toner cartridge 3 is also configured to open and replace the cover 3a provided on the front and side surfaces of the image forming apparatus 1, and the cover 3a is provided with a cover open / close detection switch 3b.

  The CRU is not limited to the process unit 2 and the toner cartridge 3 described above, and an appropriate component such as a fixing device can be formed in the form of the CRU according to the necessity for maintenance and replacement.

  Data recorded in the non-volatile memories 26 and 31 is read and referred to by the control unit 10. By referring to the identification information, it is possible to determine whether or not an appropriate unit is attached. When an inappropriate unit is attached, it is displayed on an operation panel (not shown) to display the user's Call attention. Further, when there is a possibility of malfunction or failure due to improper installation of the unit, the operation of the image forming apparatus 1 may be stopped.

  In addition, since information related to the usage time needs to be updated as appropriate, data related to the information is written from the control unit 10 to the nonvolatile memories 26 and 31.

  The written data relating to the usage time is read out and referred to by the control unit 10, and is used for correction of characteristics when the characteristics change depending on the usage time. In addition, when the usage time has passed a predetermined usable time limit, a display is made to prompt the user to replace the user.

  The nonvolatile memories 26 and 31 are supplied with a voltage of about 5 V (second power supply voltage) from, for example, a “5 V power supply” (second power supply) 7.

  The “5V power supply” 7 receives a voltage (first power supply voltage) of about 24V from the “24V power supply” (first power supply) 5 and steps down the voltage to generate a DC voltage of about 5V.

  A time constant circuit 6 is provided between the “24 V power supply” 5 and the “5 V power supply” 7. The time constant circuit 6 includes, for example, an electrolytic capacitor and a resistor. Even when the output of the “24V power supply” 5 is turned off, the input terminal of the “5V power supply” 7 is not instantaneously reduced, It slowly decreases over time determined by the time constant.

  The “5V power supply” 7 can generate a voltage of 5V if its input voltage is slightly higher than the output voltage of 5V, for example, about 7V (limit voltage) or more.

  When the image forming apparatus 1 is turned off, or when the image forming apparatus 1 is not operated for a predetermined time and as a result the image forming apparatus 1 shifts to the power saving mode (sleep mode), the input of “24V power supply” 5 The side switch 4 is turned off, and the output of the “24V power supply” 5 becomes zero almost instantaneously. However, at the input of “5 V power supply” 7, the voltage is gradually decreased from 24 V by the time constant circuit 6. As a result, the time from when the “24V power supply” 5 is turned off until the input voltage of the “5V power supply” 7 drops to the limit voltage of about 7V (voltage drop time), the voltage of 5V is “5V It is possible to operate the nonvolatile memory 26 normally by being supplied from the “power supply” 7 to the nonvolatile memories 26 and 31.

  The voltage at the output terminal of the “24 V power supply” 5 is compared with a predetermined threshold, for example, about 22 V, in the voltage detection unit 8, and the result is input to the control unit 10. This determination is for detecting the timing when the “24V power supply” 5 is turned off.

  Further, the voltage at the input terminal of the “5V power supply” 7 (the output terminal of the time constant circuit 6) is also compared and determined by the voltage detector 9 with a predetermined threshold, for example, about 7V. This determination is to detect the limit timing at which the output of the “5V power supply” 7 can normally output a voltage of 5V when the input voltage of the “5V power supply” 7 drops from 24V.

  The determination results of the voltage detection units 8 and 9 are input to the control unit 10. These voltage determination results are used for controlling the write timing of the nonvolatile memories 26 and 31 together with the cover open / close detection switches 2b and 3b.

(2) Operation The operation of the image forming apparatus 1 configured as described above, in particular, the read and write control operations of the nonvolatile memories 26 and 31 will be described below.

  Since the operation of the process unit 2 with respect to the nonvolatile memory 26 and the operation of the toner cartridge 3 with respect to the nonvolatile memory 31 are not substantially different, the operation of the process unit 2 with respect to the nonvolatile memory 26 will be described below.

  FIG. 2 is a flowchart illustrating a processing example of read / write control of the nonvolatile memory 26 performed by the control unit 10.

  First, in step ST1, the recording data of the CRU nonvolatile memory 26 is read. In the present embodiment, the read timing is not particularly specified, and for example, the recording data is read by accessing the nonvolatile memory 26 when the power is turned on. After power activation, it may be read at an appropriate constant cycle.

  In step ST2, it is determined whether or not a “write error flag” is set for the read data. The “write error flag” is used when the controller 10 determines that an error has actually occurred or the possibility that an error has occurred is high when data is written from the controller 10 to the nonvolatile memory 26. To the non-volatile memory 26.

  If the “reading error flag” is not set, the process proceeds to step ST3, and the data on the main body side (control unit 10) of the image forming apparatus 1 is updated with reference to the read CRU data.

  On the other hand, when the “reading error flag” is set, it is determined that the reliability of the recorded data (the previously written data) is low, so that the control unit 10 again stores the data in the nonvolatile memory 26 of the CRU. Then, writing is performed (step ST4), and the process proceeds to step ST5.

  In step ST5, it is determined whether the CRU is usable based on the read data. For example, from the identification information of the read CRU, when the CRU is not an appropriate unit, it is determined that it cannot be used. Further, it is determined that the CRU is unusable from the read usage time information even when the CRU has passed the usable time limit.

  If it is determined that it cannot be used, in step ST6, the “unusable flag” is written in the non-volatile memory 26 of the CRU and the process is terminated. At this time, an indication that the user cannot use the information may be displayed to prompt the user to replace the CRU.

  When it is determined that the CRU is usable, the image forming apparatus 1 starts or continues normal operation.

  While the image forming apparatus 1 is operating, the control unit 10 always monitors the open / closed state of the cover 2 a and the operating state of the “24V power supply” 5.

  The open / closed state of the cover 2a is detected by a cover open / close detection switch 2b provided on the cover 2a and notified to the control unit 10. When the cover 2a is opened, the control unit 10 starts writing to the non-volatile memory 26 of the CRU at that time, and ends the writing operation when predetermined data has been written. FIG. 3 is a diagram illustrating this operation.

  Conventionally, the data write operation from the control unit 10 to the nonvolatile memory 26 has been performed without considering the state on the CRU side. For example, the control unit 10 performs writing to the nonvolatile memory 26 at a constant cycle. For this reason, if the user pulls out the CRU for exchange during the writing period, there is a problem that data being written is destroyed.

  In the present embodiment, the occurrence of the above problem is prevented by limiting the write timing to the nonvolatile memory 26 to a specific case. One limitation of the write timing is when the cover 2a is opened (step ST7 and step ST9).

  When replacing the CRU, the user always opens the cover 2a. The amount of write data is not so large, and the time required for writing all data is, for example, about 700 ms or less at the maximum. Therefore, the writing of data to the nonvolatile memory 26 is surely completed before the user accesses the CRU after opening the cover 2a, and the possibility that the CRU is extracted during the data writing period is eliminated.

  Another limitation of the write timing is when the “24V power supply” 5 is turned off. Specifically, after the “24V power supply” 5 is turned off, data is written into the nonvolatile memory 26 only during the voltage drop time described above (steps ST8 and ST9).

  In such a form, the latest data is written to the nonvolatile memory 26 every time the image forming apparatus 1 is turned off, so that there is no concern that old data will remain in the CRU.

  Further, although a mode in which the image forming apparatus 1 is always used without being turned off without turning off the main power supply is also conceivable, the present image forming apparatus 1 usually has a “power saving mode”. The “power saving mode” is a mode in which the main power supply system is turned off except for a part of the power supply when the image forming apparatus 1 is not operated for a certain period of time. Accordingly, in the “power saving mode”, the “24V power supply” 5 is also turned off. For this reason, even when the power supply is always used, the latest data is written to the non-volatile memory 26 of the CRU when shifting to the “power saving mode”.

  The voltage drop time can be changed by changing the capacitance of the electric field capacitor of the time constant circuit 6 and is set with an appropriate margin in consideration of the amount of data written to the nonvolatile memory 26 and the writing speed. .

  FIG. 4 is a diagram illustrating a situation where data is written to the nonvolatile memory 26 within the voltage drop time. When the voltage detection unit 8 detects that the “24V power supply” 5 is turned off, the control unit 10 starts writing data to the nonvolatile memory 26 and before the output voltage of the “5V power supply” 7 decreases. The data writing is finished (before the output voltage of the time constant circuit 6 reaches about 7 V which is the limit voltage).

  Steps ST10 to ST12 show processing when data writing is not completed within the set voltage drop time for any reason.

  The control unit 10 monitors the output voltage of the time constant circuit 6 during the data writing, and if the output voltage of the time constant circuit 6 falls below about 7V before the writing is completed, an error occurs in the data writing. Therefore, it is determined that there is a high possibility that the “write error flag” is set in the nonvolatile memory 26.

  This “write error flag” is referred to in step ST2 when data is read.

  As described above, according to the image forming apparatus 1 and the control method thereof according to the present embodiment, even when an attempt is made to attach / detach the CRU to the nonvolatile memory 26 built in the CRU during energization. , Information can be written reliably. In addition, by writing data when the image forming apparatus 1 is powered off or shifted to the “power saving mode”, it is possible to always update the contents of the nonvolatile memory 26 using the latest data.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, the constituent elements over different embodiments may be appropriately combined.

1 is a diagram illustrating a configuration example of an image forming apparatus according to an embodiment of the present invention. 5 is a flowchart showing an example of a read / write control method for a non-volatile memory built in a CRU among control methods for an image forming apparatus according to an embodiment of the present invention. The figure which shows typically the relationship between the timing which opens the cover for CRU replacement | exchange, and the data write timing with respect to a non-volatile memory. The figure which shows typically the relationship between the voltage drop time of "24V power supply", and the data write timing with respect to a non-volatile memory.

Explanation of symbols

1 Image forming apparatus 2 CRU (process unit)
2a Cover 2b Cover open / close detection switch 3 CRU (toner cartridge)
3a Cover 3b Cover open / close detection switch 5 “24V power supply” (first power supply)
6 Time constant circuit 7 “5V power supply” (second power supply)
8 Voltage detection unit 9 Voltage detection unit 10 Control unit

Claims (8)

A replaceable unit with built-in non-volatile memory;
A cover that opens and closes when replacing the replaceable unit;
A detector for detecting opening and closing of the cover;
A first power supply for outputting a first power supply voltage;
A second power supply for stepping down the first power supply voltage and converting it to a second power supply voltage to supply power to the nonvolatile memory;
A voltage detector for detecting the first power supply voltage;
When the detection unit detects that the cover is opened, or the first power supply is turned off and the first power supply voltage detected by the voltage detection unit is lower than a predetermined threshold value. When the output voltage of the first power source drops from the predetermined threshold voltage to a limit voltage that can generate the second power source voltage, the non-volatile memory is A control unit for writing predetermined data,
With
The controller is
When writing of the predetermined data is not completed during the voltage drop time, a write error flag is set in the nonvolatile memory together with the predetermined data,
When the write error flag is set when the nonvolatile memory is read, the predetermined data is written to the nonvolatile memory again.
Image forming apparatus characterized by. A time constant circuit is provided between the first power source and the second power source,
The voltage drop time can be changed by adjusting the time constant of the time constant circuit.
The image forming apparatus according to claim 1 . The replaceable unit is a unit including at least one of a toner cartridge for storing toner and a process unit.
The image forming apparatus according to claim 1. The predetermined data to be written to the nonvolatile memory includes identification information for identifying the replaceable unit, information on the usage time of the replaceable unit, and information indicating the remaining amount of consumables stored in the replaceable unit. , Data indicating at least one of
The image forming apparatus according to claim 1. A replaceable unit containing a non-volatile memory, a cover that opens and closes when replacing the replaceable unit, a first power supply that outputs a first power supply voltage, and a step-down from the first power supply voltage. A control method for an image forming apparatus, comprising: a second power source that converts the power source voltage into a power source voltage of 2 and supplies power to the nonvolatile memory ;
Detecting the opening and closing of the cover;
Detecting the first power supply voltage;
When it is detected that the cover is opened, or when the first power supply is turned off and the detected first power supply voltage falls below a predetermined threshold, the first power supply output voltage, between the voltage of the predetermined threshold voltage drop time drops to a product capable limit voltage the second supply voltage, write the predetermined data to the nonvolatile memory,
When writing of the predetermined data is not completed during the voltage drop time, a write error flag is set in the nonvolatile memory together with the predetermined data,
When the write error flag is set when the nonvolatile memory is read, the predetermined data is written to the nonvolatile memory again.
A control method for an image forming apparatus. The voltage drop time can be changed by adjusting a time constant of a time constant circuit provided between the first power source and the second power source.
The method of controlling an image forming apparatus according to claim 5 . The replaceable unit is a unit including at least one of a toner cartridge for storing toner and a process unit.
The method of controlling an image forming apparatus according to claim 5 . The predetermined data to be written to the nonvolatile memory includes identification information for identifying the replaceable unit, information on the usage time of the replaceable unit, and information indicating the remaining amount of consumables stored in the replaceable unit. , Data indicating at least one of
The method of controlling an image forming apparatus according to claim 5 .

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