JP2000132464A - Data writing method and device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily discriminate the degree of reliability of the data even when a data writing process is interrupted by preparing a step where a cause is detected for the interruption of the data writing process and a step where the data are additionally written according to the detection result of the said detecting step. SOLUTION: When a writing process is started, the value of a variable M having the value of a marker bit that is added in a word writing mode is set at 0 (100). Then it is checked whether or not a factor such as the cut-off of a power supply is caused to interrupt the writing process before every word is written into an EEPROM (105). If no factor of the said interruption is detected, the writing process is started in a step 106. Then the occurrence or non-occurrence of an interruption factor is confirmed in the step 105 (107) for deciding the value of the marker bit before every word is written. If the cause of an interruption occurrence is detected, the marker bit is set at 1 (108) and the words are written (109).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for writing data to a nonvolatile storage device such as an EEPROM, and an image forming apparatus using the nonvolatile storage device for managing parts inside the device.

[0002]

2. Description of the Related Art In an image forming apparatus, in particular, in a color copying machine or a full-color printer, in order to obtain high-quality output without being affected by aging of a main body and a replacement part, or to avoid a situation that causes a serious failure. Some have a nonvolatile storage device and a mechanism for monitoring a state change of the image forming apparatus or the replacement part from the time of production / shipment even after the power is turned off.

[0003] These stores, for example, the accumulated use time in order to accurately grasp the life of the main body, and the failure information before the power is turned off.

By the way, as means for storing such information, EEPRO which can be easily connected at low cost is used.
Memory devices such as M are often used. The feature of this memory device is that it can be mounted with a simple configuration at low cost, but has the disadvantage that it takes time to write. Therefore, if a write operation is being performed when a failure such as a power failure occurs, it is highly likely that accurate storage contents cannot be guaranteed.

[0005] These problems do not occur during a normal operation, especially in a standby state or the like, but writing to a memory tends to be unstable in an emergency. And you have to remember the information you need in an emergency.

Conventionally, in order to guarantee the accuracy of the stored contents in this case, data for error checking such as a checksum is added to the entire data. It is determined that there is an error or that writing could not be performed normally at the time of writing, and that the replacement part or main body mounting the memory is determined to be faulty.

[0007]

However, in the method of diagnosing a failure by checking the entire data with the data for error check, even if there is an abnormality in a part of data which is not so important, it is determined that the memory is abnormal and cannot be used. turn into. Since this determination is made regardless of whether the replacement part is a completely new part or an old part, particularly when such an error is detected in a new part, the convenience of the main body and the replacement part is significantly reduced.

In order to stably complete the writing, there is a method of maintaining the power during the writing period by, for example, an auxiliary power supply when the power is turned off during the writing. However, these methods increase the cost and increase the size of the device. To make
In particular, it is not suitable for an image forming apparatus for personal use.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to easily determine how much data can be trusted when recording data in a nonvolatile storage device, even if the data writing process is interrupted. An object of the present invention is to provide a method and an apparatus for writing data which can be determined.

Another object of the present invention is to provide an image forming apparatus which stores information in a non-volatile storage device for the purpose of component management or the like, and which can operate as much as possible even if an error is detected in data in the non-volatile storage device. An object of the present invention is to provide an image forming apparatus capable of maintaining a state.

That is, the gist of the present invention is a method of writing data to nonvolatile storage means, wherein a step of detecting the occurrence of a factor that interrupts data writing before the start of data writing and during the writing process, A step of adding data corresponding to the result of the detection step and writing the data for each predetermined unit of data to be written to the storage means.

Another aspect of the present invention is a data writing device having nonvolatile storage means for writing data in a predetermined unit to the nonvolatile storage means, wherein data writing is started before data writing and during writing processing. Detecting means for detecting the occurrence of a factor that interrupts data writing, and data writing means for adding and writing data according to the result of the detecting means for each predetermined unit of data to be written to the storage means. Data writing device.

Still another aspect of the present invention is an image forming apparatus having a nonvolatile memory and a management unit for managing components based on data stored in the nonvolatile memory. Detecting means for detecting the occurrence of a factor that interrupts data writing before the start of data writing and during the writing process; and for each predetermined unit of data to be written to the non-volatile storage means, data corresponding to the result of the detecting means is written. An image forming apparatus having data writing means for additionally writing.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, when data writing to a storage device is interrupted, when the next reading is performed, the last writing was interrupted, and where was the interrupted location? Is characterized in that it can be detected.

Specifically, a bit serving as a marker is provided for each unit of data writing or for each word if the storage device is a memory device. Further, a means for detecting the interruption of writing is provided, and the time from the detection of interruption to the point where writing is disabled or data in the memory occurs is at least two times.
Words are configured to be guaranteed. The marker bit is written, for example, as 0 in normal writing and as 1 when interruption of writing is detected.

By this means, the next time the data is read from the memory, the portion where the marker bit changes from 0 to 1 and from 1 to 0 is detected, and the writing is interrupted. The starting point of the data that cannot be specified can be specified.

In addition, by dividing the data into blocks according to the importance of the data and writing each block, an unreliable data block can be specified, and the data of other blocks can be used normally.

As a result, a memory error due to an emergency interruption in writing data can be reduced without hindering downsizing and cost reduction, and even if a worst-case memory error occurs, the image forming apparatus can be as small as possible depending on the importance of data. Do not interrupt operation.

[First Embodiment] The present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a data writing device portion of the image forming apparatus of the present invention.
In the present embodiment, a case is shown in which a nonvolatile storage device is provided as a component of the image forming apparatus. In FIG. 1, 1 is a replacement part 2
Is an image forming apparatus. The image forming apparatus 1 has a CPU 3
Is controlled by 5 is CPU and EEPROM4
Shows the power line to the.

The replacement part 2 is a photosensitive drum unit which also serves as a waste toner box in the present embodiment. The photosensitive drum unit 2 includes a photosensitive drum for image formation and a waste toner box for storing waste toner after image formation, and is a replacement part that needs to be replaced after use for a predetermined life. The EEPROM 4 built in the replacement part has the contact 8
Through the serial communication with the CPU 3, the information such as the total usage time for calculating the life of the photosensitive drum is maintained.
Serial communication is performed by four communication lines 9A, 9B, 9C, and 9D.

Reference numeral 6 denotes a voltage maintaining device which has a role of a backup power supply for notifying the CPU 3 of power-off and maintaining a voltage to the CPU and the EEPROM while the CPU writes at least two words to the EEPROM 4. Since this can be implemented at low cost by a known technique using a capacitor or the like, detailed description will be omitted.

The EEPROM 4 has 1 word and 16 bits.
It is a non-volatile memory that can store 6 words of data.
Data storage is in word units, and communication lines 9A, 9B, 9C
This is performed by sending a write instruction command, a write address, and write data from the CPU through the CPU.

Next, how to use the EEPROM 4 (memory map) will be described. FIG. 2 is a diagram showing an example of the relationship between the memory map of the EEPROM 4 and the original data on the main memory of the CPU. In the present embodiment, the EEPROM 4
Is divided into three areas. These three areas are divided into three groups according to the importance of data or the necessity of the latest data.

The memory of the EEPROM 4 has one word (16
1) is used as a marker bit. This is used not as an area used as backup data but as information indicating whether stored data is reliable. Therefore, the area where the actual data can be used per word is 15 bits, and A
The usable number of bits in the area is 60 bits, the usable number of bits in the B area is 60 bits, and the usable number of bits in the C area is 120 bits. Of these, in the C area, since 8 bits other than the marker bits are used as a checksum for the entire data (16 words), the actually usable area is 112 bits.

In the present embodiment, the history information of optical detection of waste toner full for judging the area A is full of waste toner, the use time history for judging the life of the photosensitive drum in the area B, and the other area in the area C are other information. It is used to store process conditions and cartridge usage history information for market research. The order in which the reliability of information is required is highest in the A area, and then in the order of the B and C areas. The reason is that if the detection of the full state of the waste toner is delayed, the main body is damaged, and if it is found that the data in the EEPROM is wrong at the worst, the operation must be forcibly stopped. Therefore, data reliability is the most necessary. Regarding the judgment of the service life of the photosensitive drum, it does not cause any damage to the main body, but if this data is wrong, it has a great effect on the image quality. The usage history information of the last cartridge indicates damage to the main unit,
Since there is little relation with the output quality, if only this part of the data is damaged, usability can be prioritized and ignored.

Next, the writing procedure of the EEPROM will be described with reference to FIG. FIG.
6 is a timing chart when writing word data. Signals / CS, DOUT, / CLO in FIG.
CK respectively correspond to the signal lines 9A, 9B, 9C in FIG. The signal line 9D shown in FIG. 1 is a signal line D for obtaining data from the EEPROM when reading from the EEPROM.
IN. The EEPROM starts storing a specified word by sequentially sending three data of a command code indicating writing by the signals / CLOCK and DOUT, a write address, and write data while the signal / CS is Low. After the signal / CS is returned to High, if the CPU has sent the correct command code, address and data, the storage of the word is completed after a predetermined time.

Here, as shown in FIG. 3, when the power is cut off and the writing process is interrupted, the writing result changes depending on the interrupted timing. That is,
If the write processing is interrupted in the section a where the CPU is transmitting the command, the address, and the data, the write instruction becomes invalid, and no new data is stored. However, in this case, old data remains. On the other hand, when the data transmission of the CPU is completed and the writing is interrupted in the section b after the signal / CS returns to High, the storage content of the word becomes undefined. In this case, no old data remains.

The procedure for accessing the EEPROM is known, and the procedure for reading is not a feature of the present invention. In the reading procedure, a read command and data indicating a read address are sent by / CLOCK and DOUT, and data is read by DIN.

As described above, when the write process is interrupted, new data is used up to the boundary of the word where the write is interrupted and up to and before the boundary, and old data is used after the word or after the word. Indicates that the word is undefined data. In any case,
If new data, undefined data, and old data are mixed, the reliability of the data as a whole is lost. Even if a checksum is taken for the entire data, it cannot be determined which part is unusable. Therefore,
In the present invention, a marker bit is used.

Next, the use method of the marker bit is EEPR
The description will be given according to the procedure for writing data to the OM. FIG.
9 is a flowchart showing a procedure for backing up data to the EEPROM. Writing of data starts from start and ends with processing ending with end.

When the writing process is started, first, the value of a variable M having the value of a marker bit added when writing a word is set to 0 (step 100). Next, CPU
3, the history data of the waste toner full optical detection stored in a predetermined area of the main memory (not shown) is read out, and
The data is converted into data of 15 bits × 4 for the area A of the EPROM 4 (step 101). Subsequently, similarly, the photosensitive drum life data in the main memory is converted into 15 bits × 4 for the area B (step 102), and the other data is converted into 15 bits × 7 + 7 bits for the area C (step 103). Next, a checksum is calculated for the entire converted data (step 104). At this time, the portion corresponding to the marker bit is set to 0, and the checksum is determined so that the sum of the bytes including the checksum becomes 1.
Thus, preparation of the actual data to be written to the EEPROM 4 is completed.

Next, the data is written into the EEPROM in word units. Before that, it is checked whether or not a factor that interrupts the writing process, such as power-off, has occurred (step 105). At this point, if the occurrence of the interruption factor is detected, the writing is not performed because there is a possibility that the data may become undefined immediately after the writing is started. If the interruption has not been detected, the writing is started from step 106.

The write word counter C is initialized (step 106). The counter C can be realized by using a counter area provided on the main memory, using a register of the CPU 3, and the like. Next, similarly to step 105, it is confirmed whether or not an interruption factor has occurred (step 107).
This check is for determining the value of the marker bit before writing each word. When the occurrence of the interruption factor is detected, the marker bit is set to 1 (step 108).

Next, a word is written (step 109). Word data is from step 100 to step 1
This is 16-bit data obtained by acquiring 15 bits from the beginning of the data prepared in step 04 and adding the value of the variable M as a marker bit to the least significant bit. The write operation shown in FIG. 3 is performed using this word data as an address C.

Completion of writing one word data (EEPR
It waits for a predetermined time as shown in the timing chart of FIG. 3 for completion of storage in the OM (step 11).
0). Some EEPROM devices have a means for knowing the completion of storage without waiting for a predetermined time, but in the present embodiment, a time for guaranteeing completion of writing is waited. When writing of one word is completed, the counter C is incremented (step 111), and it is confirmed whether or not the last address has been written (step 1).
12). If the processing has not been performed up to the last address, the processing from step 107 is repeated, and the writing processing of the remaining word data is performed.

When the above processing can be completed without being interrupted by turning off the power, the marker bits are all written as 0, as shown in FIG. If a factor that interrupts the writing process is detected in step 107, some word data whose marker bits have become 1 are written and the process is interrupted.

Next, a method of determining a reliable data range from the data content of the EEPROM 4 when an interruption factor occurs during the writing process will be described. Hereinafter, a case will be described in which the interruption factor of the writing is the power interruption, and the time during which the voltage maintaining device 6 maintains the voltage when the power interruption is detected is the time required to write the data of four words.
In this case, even if the last word written when the power supply to the CPU 3 and the EEPROM 4 is actually interrupted becomes indefinite data, processing is performed after at least three words of data with a marker bit of 1 have been written. Will be interrupted.

FIG. 5 is a diagram showing the contents of the EEPROM 4 when the writing process is interrupted in the above situation. Looking at the marker bits from the lower address (write start address) to the upper address, it can be seen that it changes from 0 to 1 and returns to 0. From FIG. 5, it can be seen that the power-off was detected during the writing of data to the address 5 or during the period from the end of writing to the start of writing to the address 6. This is the word on the 1 side of the boundary that changes from 0 to 1, that is, the word in which the word data at address 6 is first written after power-off detection. Thereafter, since the marker bit is written with 1 until the power supply is actually interrupted, the power supply is interrupted during the writing process of the address 9 or from the end of the writing to the start of the data writing to the address 10.

As described with reference to the timing chart of FIG. 3, when writing of a certain word is interrupted due to power-off, the case where old data remains,
There are two cases where the word becomes undefined data. Therefore, it cannot be determined whether the word (address 10) in which the marker bit becomes 0 again has a result that old data remains when the word is written or is indefinite data. In addition, it cannot be determined whether the last word (address 9) whose marker bit immediately before is 1 is the last word that could be normally written with the marker bit being 1 or whether it was interrupted and became undefined data.

However, since the marker bit is set to 1 for all the words to be written after the power-off detection until the power supply is actually stopped, the word written before the two words on the boundary as shown in FIG. (Address 0
8) is the latest data, and subsequent words (address 11)
To 15) can be determined as old data, and it can be seen that they can be used reliably. Here, it can be seen that when the interruption of the writing is detected by the marker bit, the data in the memory can be divided into three areas. The latest data, unreliable data (possibly indeterminate), or old data.

When the marker bit remains at 1 until the last address as shown in FIG. 6, the last word becomes unreliable data. In this case, all the remaining words are the latest data. Further, when there are two boundaries where the marker bit changes from 1 to 0 as shown in FIG. 7, the reliability of the data may be evaluated based on the change point on the upper address side. Also, as in the present embodiment,
In the case where data with high importance is written first and data with low importance is written later, as shown in FIG. 8, the data below the boundary where the first interruption is detected is determined as unreliable data, and the importance is determined. The reliability of the data of the high-order address having a higher value may be more reliably evaluated.

The processing after the evaluation of the type and reliability of data as described above will be described. As described above, in the present embodiment, the history information of the waste toner full optical detection for determining the area A is full of waste toner, the usage time history for determining the life of the photosensitive drum in the area B, and other processes in the area C are described. The configuration is such that data of high importance such as conditions and cartridge use history information for market research are written first, and low data is written later. Therefore, if the unreliable data area is included in the A area (addresses 0 to 3), the operation of the entire image forming apparatus is stopped as a memory failure. If the unreliable data area is not included in the A area and the unreliable data area is included in the B area (addresses 4 to 7), a warning that affects the image quality is displayed, but the operation is not stopped. In this case, the time to replace the photosensitive drum can be determined by the user. If the warning is included only in the area C, the warning is issued at a lower level, and does not affect the operation of the image forming apparatus.

If all the marker bits are 0 and the check by the checksum results in an error, the EEP
It is determined that the ROM device has failed. Thereby, EEP
It is possible to distinguish between a failure of the ROM device and a data abnormality due to the interruption of writing.

In the case of a data error that does not stop the operation, the latest data is created from the read result, and the EEPROM data is updated on the spot. by this,
The marker bits are all reset to 0, and the next write interruption can be detected. If the power is turned off during the update and the writing is interrupted, there is a possibility that the interrupted location cannot be detected. However, this frequency is so low that it can be ignored.

As described above, the marker bits are provided in units of words to detect the interruption of writing due to the power supply cutoff, and the data in the backup memory is grouped by reliability by detecting the writing interruption word by the marker bits at the time of reading. In addition, by grouping the data in the backup memory according to the importance of the information, the operation of the image forming apparatus can be maintained without reducing the usability for the damage of the data of low importance. It becomes possible.

[Second Embodiment] In the first embodiment, the power-off is used as a factor for interrupting writing. However, in addition to this, for example, a power-off due to opening of a door of an image forming apparatus may be a factor for interrupting writing. It is valid. In particular, there is a possibility that the user may suddenly remove the photosensitive drum or the like, which is a replacement part, from the image forming apparatus during memory access. This is more useful if implemented as a factor of interruption of writing. Also, if there is a possible interruption factor in the data writing process such as when a forced reset process is performed in addition to power-off, a sensor that detects the occurrence of the factor is provided. By maintaining the time operation, various factors can be dealt with.

FIG. 9 is a main block diagram showing an example of a configuration for coping with various interruption factors. In the figure, FIG.
The same reference numerals are given to the same components as those described above, and description thereof will be omitted. In the present embodiment, the sensor block 20 that collectively receives inputs from various sensors (not shown) that detect the occurrence of an interruption factor other than the power interruption and the voltage maintaining device 6 detects the output signal of the sensor block 20 by the power interruption detection A delay circuit 23 for delaying at least the same time as the voltage is sometimes maintained, and a switch 22 for outputting the output signal of the sensor block 20 as it is or delayed by the delay circuit 23 are newly provided.

The sensor block 20 monitors the outputs of the various sensors and, when receiving a state change that may cause interruption of data writing to the EEPROM 4, switches the switch 22 to select the output signal of the delay circuit 23 and indicates the state change. The signal delays initiating the process of interrupting the data write. At the same time, it notifies the voltage maintenance device 6 that the write interruption factor has been detected. Thus, the writing of the word data with the marker bit set to 1 is started.

As described above, even in the case where the data writing process may be interrupted due to factors other than the power interruption, the reliability of the data can be reliably grasped.

[Third Embodiment] The third embodiment is the same as the first embodiment in terms of memory access and basic configuration, so that detailed description is omitted, and the third embodiment is different from the first embodiment. I will explain only.

The third embodiment is different from the third embodiment in that the EEPROM 11, which is a non-volatile storage means, is not a replacement part but is built in the main body of the image forming apparatus. FIG. 10 is a block diagram showing the third embodiment.

In FIG. 10, reference numeral 11 denotes a main body EEPROM,
Reference numeral 10 denotes a communication line to the main body 11. Main body EEPROM1
Reference numeral 1 stores data for measuring the number of discharged sheets and the life of non-replaced parts in the image forming apparatus. In the present embodiment, for example, the life data is treated as high-priority data that is targeted for failure in the event of a data error, and the integrated number of discharged sheets is treated as low-priority data for warning display only even in the case of a data error. The method of using the EEPROM, the method of writing, and the method of evaluating the reliability of the data are the same as those in the embodiment of the stand 1, and therefore the description is omitted.

[0053]

Other Embodiments In the above embodiment, the present invention has been described based on an example in which the present invention is applied to an image forming apparatus. However, the present invention is not limited to the image forming apparatus but can be applied to any apparatus. In addition, any device other than the EEPROM can be used as the nonvolatile storage device.

The present invention may be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.). That is, the location where data is written and the occurrence of a factor that interrupts data writing may be detected at different locations.

In this embodiment, a photosensitive drum is used as an example of a replacement part, and an EEP is used as an example of a nonvolatile memory.
Although a ROM is mentioned, the present invention is not limited to this, and the present invention is effective even when another memory device is used for another replacement part.

[0056]

As described above, in the present invention,
When writing data to the non-volatile storage device, by providing a bit for detecting a write interruption for each predetermined write unit, even if an error occurs during the write and the process does not end normally, This has the effect that reliable data can be determined. Furthermore, if the writing process is interrupted, the error handling method is changed according to the data importance of the unreliable area, so that the device can be used except when it is really a problem. The configuration has the effect of preventing usability from deteriorating.

[Brief description of the drawings]

FIG. 1 is a conceptual block diagram of an image forming apparatus according to a first embodiment.

FIG. 2 is a diagram showing a relationship between a memory map of a backup memory (EEPROM) and data on a CPU main memory.

FIG. 3 is a timing chart showing an EEPROM writing procedure.

FIG. 4 is a flowchart illustrating a writing process.

FIG. 5 is a diagram illustrating an example of a memory map when writing is interrupted;

FIG. 6 is a diagram showing another example of a memory map when writing is interrupted.

FIG. 7 is a diagram illustrating a method for determining data reliability when there are two change points.

FIG. 8 is a diagram illustrating another method of determining data reliability when there are two change points.

FIG. 9 is a conceptual block diagram of an image forming apparatus according to a second embodiment.

FIG. 10 is a conceptual block diagram of an image forming apparatus according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Replacement part 3 CPU 4,11 EEPROM 20 Sensor block 22 Switch 23 Delay circuit

Continued on front page F-term (reference) 2C061 AP04 AQ06 AR01 HJ06 HK11 HV02 HV04 HV39 5B018 GA01 HA13 HA31 LA03 QA05 QA15 RA11 5B021 DD19 MM04 NN15 NN19 5C062 AB44 AB49 AC22 AC58 AC60 AE15 AF00 AF06 AF07 BA00

Claims (24)

[Claims] 1. A method for writing data to a non-volatile storage means, comprising: detecting an occurrence of a factor that interrupts the data writing before starting to write the data and during the writing process; Adding data corresponding to the result of the detection step and writing the data for each predetermined unit of data. 2. The data writing method according to claim 1, further comprising a step of maintaining the data writing process for a predetermined time when the occurrence of the interruption factor is detected during the data writing process. 3. The data writing method according to claim 2, wherein the predetermined time is equal to or longer than a time required for writing two predetermined units of the data. 4. The apparatus according to claim 2, wherein the predetermined time is equal to or longer than a time required to write two predetermined units of the data and less than a time required to write three predetermined units of the data. Data writing method. 5. The data writing method according to claim 1, wherein the predetermined unit is a minimum unit that can be written to the nonvolatile storage unit. 6. The data writing method according to claim 1, wherein an order of writing to said nonvolatile storage means is determined according to importance of said data to be written. 7. The data writing method according to claim 1, wherein the factor of interrupting the data writing is power-off. 8. The method according to claim 1, further comprising the step of writing error determination data with respect to all data written during the writing process after writing the last predetermined unit data. Data writing method described. 9. The data writing method according to claim 1, wherein said nonvolatile storage means is an EEPROM. 10. A data writing device having nonvolatile storage means for writing data to said nonvolatile storage means in predetermined units, wherein said data writing is interrupted before data writing is started and during writing processing. A data writing apparatus comprising: a detection unit that detects the occurrence of a factor; and a data writing unit that adds and writes data corresponding to a result of the detection unit for each predetermined unit of data to be written to the storage unit. . 11. The data writing device according to claim 10, further comprising: a unit for maintaining the data writing process for a predetermined time when the detecting unit detects the occurrence of the interruption factor during the data writing process. . 12. The data writing device according to claim 11, wherein the predetermined time is equal to or longer than a time required to write two predetermined units of the data. 13. The method according to claim 11, wherein the predetermined time is equal to or longer than a time required to write two predetermined units of the data and less than a time required to write three predetermined units of the data. Data writer. 14. The data writing device according to claim 10, wherein the predetermined unit is a minimum unit that can be written to the nonvolatile storage unit. 15. The data writing device according to claim 10, wherein said nonvolatile storage means has a writing area according to importance of said data to be written. 16. The data write interruption is caused by power-off.
The data writing device according to any one of the above. 17. The method according to claim 10, wherein the data writing unit writes error determination data for all data written during the writing process after finishing writing the last predetermined unit data. The data writing device according to any one of the above. 18. The method according to claim 18, wherein said nonvolatile storage means is an EEPROM.
15. The data writing device according to claim 10, wherein: 19. An image forming apparatus comprising: a nonvolatile memory; and a management unit that manages a component based on data stored in the nonvolatile memory, wherein before the start of writing data to the nonvolatile storage unit. And during the writing process, detecting means for detecting the occurrence of a factor that interrupts the data writing, and for each predetermined unit of data to be written to the non-volatile storage means, adding data corresponding to the result of the detecting means. An image forming apparatus, comprising: data writing means for writing. 20. The image forming apparatus according to claim 19, further comprising: a unit that maintains the data writing process for a predetermined time when the detecting unit detects the occurrence of the interruption factor during the data writing process. . 21. The image forming apparatus according to claim 19, wherein the predetermined time is equal to or longer than a time required for writing two predetermined units of the data. 22. The image forming apparatus according to claim 19, wherein the non-volatile memory is included in a component to be managed. 23. The image forming apparatus according to claim 19, wherein the nonvolatile memory is not included in a component to be managed. 24. The image forming apparatus according to claim 19, wherein said component includes a photosensitive drum.