JP4041668B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine or a printer.
[0002]
[Prior art]
Generally, in this type of image forming apparatus, the photoconductor is consumed as it is used, so information relating to the degree of wear is read from the photoconductor and toner status, and a reference value for determining the toner status is also corrected. There is a need. In other words, since conditions such as deterioration change between a new photoreceptor and a fully used photoreceptor, the conditions for supplying toner also change depending on the deterioration.
[0003]
In order to correct this, a predetermined pattern image is written and formed in a region outside the image writing range on the photosensitive member, and the potential of the pattern image and the photosensitive member background potential are detected by a sensor (so-called P sensor). Based on these detected potential relationships, the degree of deterioration of the photoreceptor is judged, and in combination with a sensor (so-called T sensor) that detects the remaining amount of toner in the developing device, the target value of the T sensor is set next time. A toner control correction value α for correction is calculated and stored in a nonvolatile memory. That is, control for correcting the reference value of the T sensor is performed based on the detection output of the P sensor. Such a series of feedback control is called process control.
[0004]
In general, a predetermined pattern image is formed on the photoconductor in an area outside the image writing range, the pattern image potential and the photoconductor background potential are detected by the P sensor, and based on the detected potential relationship. The reference value of the T sensor used to replenish the toner is changed in combination with the T sensor that determines the degree of deterioration of the photoreceptor and detects the remaining amount of toner. As a result, the toner replenishment amount can be appropriately replenished from a plurality of conditions such as not only the remaining amount of toner but also the degree of deterioration of the photoreceptor. More specifically, the electric potential of a predetermined pattern image, the electric potential of a background stain portion (a state where toner is thinly placed on the photoconductor by changing the value of the developing bias), and the electric potential of the photoconductor background portion Is read by the P sensor, the degree of deterioration of the photoconductor is determined based on the voltage ratio, and the toner control correction value α for correcting the target value of the T sensor is determined.
[0005]
[Problems to be solved by the invention]
However, in the manufacturing process of image forming apparatuses such as copying machines and printers, the process unit including the photoconductor does not use the actual product process unit until the inspection is completed on the production line. In most cases, a factory jig (a jig process unit dedicated to the process) is used for inspection instead of the process unit. When such a factory jig is used, the conditions are different from those of a normal product process unit. Therefore, the toner control correction value α for the T sensor is the normal mode in which the product process unit is mounted. The shifted value is stored in the nonvolatile memory.
[0006]
In other words, when a problem occurs in the factory assembly process, when the process surroundings including the photosensitive member is confirmed (using a factory jig) as the evaluation in order to investigate the cause, the toner is used. The value of the control correction value α is significantly different from the environment (product) in which the original product process unit is mounted and set to the normal mode, and the toner control correction cannot be performed properly. . This is also the case in the opposite case, for example, when maintenance accompanying the replacement of the photosensitive member or the like becomes necessary in the market.
[0007]
An object of the present invention is to set a toner control correction value α when a failure occurs in a factory assembly process, when an in-process mode is set as an evaluation and a process including the photosensitive member is checked using a factory jig. The value of is significantly different from the normal use environment where the original product process unit is installed and set to the normal mode, and as a result, it is possible to surely avoid the trouble that the toner control correction cannot be properly performed. It is.
[0008]
Another object of the present invention is to cope with a case where the toner control correction value α is not desired to be cleared even after returning to the normal mode depending on the use conditions in the in-process mode.
[0009]
In addition, the object of the present invention is to clear the toner control correction value α after being put on the market as a product, considering that the toner control correction value α should not be cleared to darkness. Tolerate only certain people.
[0010]
[Means for Solving the Problems]
  According to the first aspect of the present invention, a predetermined pattern image is formed on the photosensitive member, and the toner control correction value α obtained based on the relationship between the potential of the pattern image and the photosensitive member background potential is stored in the nonvolatile memory. In an image forming apparatus used as one of the elements for calculating the toner density,in frontUse factory jigs instead of product process units containing photoconductors.EquippedEquipped with in-process mode and product process unit to be usedUseMode switching means for switching the normal mode to be usable, and forced clear means for returning the toner control correction value α stored in the nonvolatile memory to a default value when the mode is switched by the mode switching means. .
[0011]
Therefore, when the mode is switched by the mode switching means, the toner control correction value α stored in the nonvolatile memory is forcibly cleared to the default value by the forced clearing means, and the toner control correction value α is used as it is. There is nothing. Also, because it is forcibly cleared, you will never forget it.
[0012]
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the forcible clearing unit stores the toner control stored in the nonvolatile memory when the in-process mode is switched to the normal mode. Return the correction value α to the default value.
[0013]
Therefore, for example, when the inspection is completed in the manufacturing process and the mode is switched from the in-process mode to the normal mode by the mode switching unit, the toner control correction value α stored in the nonvolatile memory is forcibly set to the default value by the forced clearing unit. Thus, the toner control correction value α in the in-process mode is not used as it is in the normal mode.
[0014]
According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the forced clearing unit is stored in the non-volatile memory when the normal mode is switched to the in-process mode. The toner control correction value α is returned to the default value.
[0015]
Therefore, for example, when a mode is switched from the normal mode to the in-process mode by the mode switching means in order to perform a test when a defect occurs in the factory assembly process, the toner control correction value α stored in the non-volatile memory. Is forcibly cleared to the default value by the forcible clearing means, and the toner control correction value α in the normal mode is not used as it is in the in-process mode.
[0016]
According to a fourth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to third aspects, further comprising a selection unit that enables or disables the operation of returning to the default value by the forced clearing unit.
[0017]
Therefore, basically, when the mode is switched, the toner control correction value α is forcibly cleared to the default value, but by setting the selection means to invalidate such an operation. If you do not want to clear, you can deal. For example, the inspection process is temporarily ended and returned to the normal mode. However, there is a case where there is a defect, the product is not shipped, and is used for a subsequent re-inspection. There are cases where it is desired to use the value of the previous inspection stage as the value of α.
[0018]
According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the image forming apparatus further comprises an authentication unit for enabling the operation of returning to the default value by the forced clearing unit.
[0019]
Therefore, the toner control correction value α can be forcibly cleared only when the operation of returning to the default value by the authenticating means is enabled, so that the toner control correction value α can be avoided from being cleared to darkness.
[0020]
According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect, the authentication unit is a unit that validates the input of a password.
[0021]
Therefore, the invention of claim 5 can be easily realized by the password input method.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described with reference to FIGS. This embodiment shows an application example to a laser printer as an image forming apparatus.
[0023]
FIG. 1 is a schematic diagram showing a schematic configuration example of a laser printer of the present embodiment in which a main body and each option are unitized. Schematically, a sheet feeding unit 3, a duplex unit 4, a finisher unit 5, a mailbox unit 6 and the like are added as optional units to a main unit 2 including a drum-shaped photosensitive member 1.
[0024]
The main unit 2 mainly includes the photosensitive member 1 for performing a series of image forming processes such as optical writing for image formation (electrostatic latent image formation), development, transfer / fixing control, and the like. Image forming process members such as a charger 7, an optical system unit 8, a developing device 9, and a transfer device 10 are arranged around the pair, a pair of registration rollers 11 upstream of the transfer device 10 in the transport direction, and a downstream side of the transport direction. A pair of fixing rollers 12 is provided. A registration sensor S <b> 1 is provided at a position immediately before the registration roller 11. In addition, a paper feed unit 13 is built in the main unit 2, and transfer paper is selectively fed from the paper feed unit 13 and the paper feed unit 3 toward the photosensitive member 1 by the paper feed rollers 14 and 15. It is configured to be paper.
[0025]
The duplex unit 4 is a unit for reversing and refeeding the transfer sheet in order to perform duplex printing in the duplex printing mode (details are omitted). The finisher unit 5 is a post-processing unit for shifting (sorting) and stapling the transferred transfer paper (details are omitted). The mail box unit 6 has a plurality of paper discharge units (in the illustrated example, three bins of paper discharge ports 1 to 3), and is a unit that discharges paper for each mail destination (details are omitted). Note that S1 to S20 shown in FIG. 1 are sensors for detecting the transfer paper at each position, and P1 to P5 indicate switching positions by a solenoid-driven switching claw for switching the transport direction.
[0026]
In such a configuration, a schematic operation centering on the main unit 2 will be briefly described. The transfer paper selectively fed by the paper feed roller 14 or 15 from the paper feed unit 13 or 3 is temporarily stopped at the position when the leading edge is detected by the registration sensor S1. On the other hand, on the photosensitive member 1 side, it is uniformly charged by the charger 7, and by irradiating the laser light corresponding to the image information by the optical system unit 8, the irradiated portion on the photosensitive member 1 and the non-irradiated portion are not irradiated. An electrostatic latent image is formed by causing a potential difference between the portions, and a visible image is formed by developing toner with the developing device 9 using the potential difference. The transfer paper once stopped is re-conveyed toward the transfer position by the registration roller 11 so that the leading edge of the image on the photosensitive member 1 and the leading edge of the transfer paper coincide with each other. The toner image on the photosensitive member 1 is transferred onto the transfer paper and further subjected to a fixing action by the fixing roller 12. Residual toner on the photoreceptor 1 is removed by cleaning by a cleaning unit (not shown). Further, the fixed transfer paper is conveyed toward the duplex unit 4, the finisher unit 5 or the mail box unit 6 depending on the mode, and undergoes necessary conveyance processing and the like.
[0027]
Next, a configuration example of the control system of the laser printer of this embodiment is shown in the block diagram of FIG. The control system includes an interface with the host machine 21 and a controller unit 22 that performs image editing and control, and an engine unit 23 that performs machine control and writing mainly using the photosensitive member 1 and the like, paper feeding control, and printer status monitoring. It is divided into and. The controller unit 22 includes a microcomputer including a controller CPU 24, a program ROM 25, a RAM 26, and the like. In addition, a host interface 27 for the host machine 21, a font ROM 28, an option RAM 29, a panel interface 31 for the operation panel 30, and an engine interface for the engine unit 23. 32 and the like, and a font cartridge 33 can be externally attached.
[0028]
On the other hand, the engine unit 23 includes a microcomputer including an engine CPU 34, an engine ROM 35 in which a program is resident, a RAM 36 having a buffer register function, and the like. In addition, a flash ROM 37, an input port 38, an output port 39, and a maintenance cycle are recorded. A readable / writable EEPROM 40 is provided, and a controller interface 42 for the controller unit 22 side via an interrupt 41, an option interface 45 for an option 44 via an interrupt 43, and the like are provided. Sensors 46 such as S1 to S20, DIP switches 47, and other input units 48 are connected to the input port 38, and each high-pressure process member 49, each clutch 50, each motor 51, and the like are connected to the output port 39. An output unit 52 is connected.
[0029]
Under such a configuration, as the overall control of the laser printer, the general control as shown in FIG. In other words, after power-on (power-on), initial setting of each state is performed. System initialization (step S1), and then interface control between the engine unit 23 side and the controller unit 22 side (reception of paper feed command, resolution setting) Request reception, receipt of paper feed / discharge outlet switching request, etc.) control to check the internal state of the engine unit 23 such as maintenance request or error occurrence, paper feed timing, high voltage on / off, etc. A task for performing sequence control, a queue task for managing information on a transfer sheet to be printed (S2 to S6), and the like are repeatedly performed. On the other hand, an interrupt module (steps S11 and S12) as shown in FIG. 4 is provided for time monitoring and control for performing each process independently of such a main sequence, and every predetermined time set by the engine CPU 34. This interrupt routine is entered and necessary interrupt processing is performed.
[0030]
Here, formation of a predetermined pattern image related to toner density control in the developing device 9 will be described. FIG. 5 is a schematic configuration diagram showing the process members around the photosensitive member 1 in more detail. As described above, around the photosensitive member 1, the laser beam L from the charger 7 and the optical system unit 8, the developing unit 9. Along with the transfer device 10, the charge eliminating needle 61, the quenching lamp (QL) 62 for discharging, etc., the potential of a predetermined pattern image formed on the photosensitive member 1 and developed by the developing device 9, the photosensitive member background potential A so-called P sensor 63 is provided opposite the photosensitive member 1 between the development position and the transfer position.
[0031]
As described above, it is necessary to read the information from the state of the photoconductor 1 and the toner according to the degree of consumption of the photoconductor 1 and correct the reference value for judging the toner state. That is, since conditions such as deterioration are changed between the new photoreceptor 1 and the fully used photoreceptor 1, the conditions for supplying toner also change depending on the deterioration. In order to correct this, a predetermined pattern image is written and formed in an area outside the image writing range on the photosensitive member 1, and the potential of the pattern image and the photosensitive member background potential are detected by the P sensor 63 and detected. The degree of deterioration of the photosensitive member 1 is judged based on these potential relationships, and the target value of the T sensor is corrected next time in combination with a T sensor (not shown) that detects the remaining amount of toner in the developing unit 9. For this purpose, a toner control correction value α is calculated and stored in the EEPROM 40 as a non-volatile memory. That is, control for correcting the reference value of the T sensor is performed based on the detection output of the P sensor 63. Such a series of feedback control is called process control.
[0032]
An example of the flow of processing from creation of a predetermined pattern image for detecting the P sensor 63 to reading of the P sensor 63 is shown in FIG. During power-on startup processing or during printing, a predetermined pattern image (P pattern image) 64 for reading the P sensor 63 is written between papers that are non-image areas, and after development, this pattern image portion ▲ 1), background stain portion (state in which the toner is thinly placed on the photoreceptor by changing the value of the developing bias) (2) and the potential of the photoreceptor background portion (3) are read by the P sensor 63 and read. Based on the relationship between the values (for example, ratio), the degree of deterioration of the photosensitive member 1 is determined, and used in combination with a T sensor that detects the remaining amount of toner in the developing unit 9 to replenish the toner. Control is performed so as to change the reference value of the T sensor. As a result, the amount of toner to be replenished can be appropriately replenished from a plurality of conditions such as the degree of deterioration of the photoreceptor 1 as well as the remaining amount of toner.
[0033]
The potential detected by the P sensor 63 at this time is shown in time series in FIG. That is, the P sensor 63 first measures the potential of the P pattern image (1) formed in the non-image area on the photoconductor 1, subsequently measures the potential of the background stain portion (2), and further measures the photoconductor. Measure the potential of the ground surface (3). At this time, the measured potentials (for example, 0.5 V, 3.5 V, and 4.0 V, respectively) change as shown in FIG. 6B due to the respective parts (1), (2), and (3). The degree of deterioration of the photosensitive member 1 is determined based on the ratio, and the toner control correction value α for correcting the target value of the T sensor is determined. This toner control correction value α is used as one of the elements for calculating the toner density.
[0034]
Here, when considering the actual situation of the laser printer according to the present embodiment, in the manufacturing process, a product process unit including a photosensitive member 1 is used as a process unit until inspection is completed on the production line. In most cases, factory jigs (in-process dedicated jig process units) are used for inspection instead of using product process units. In-process mode using such factory jigs and product processes The normal mode using the unit can be switched by the mode switching means. As a result, for example, when a defect occurs in the factory assembly process, the process is set to the in-process mode as an evaluation to investigate the cause, and the process including the photoconductor is confirmed using a factory jig, and the inspection is completed. After that, the product process unit is mounted and completed as a product, and returned to the normal mode usable in the market.
[0035]
When such mode switching, for example, switching to the in-process mode is performed, the conditions differ from those of the normal product process unit. Therefore, the toner control correction value α for the T sensor is the normal mode using the product process unit. There is a possibility that an offset value is stored in the EEPROM 40 and proper toner control correction cannot be performed.
[0036]
Therefore, in this embodiment, it is necessary to clear the toner control correction value α when a factory jig is used for inspection in the in-process mode, and after that, when the mode is exited from the in-process mode and returned to the normal mode. For this reason, as shown in the flowchart of FIG. 7, when the mode is switched, the toner control correction value α is forcibly cleared. In this embodiment, the RAM area for determining whether the mode is the in-process mode or the normal mode is F $ MODE. The configuration of this F $ MODE is defined as 1 byte, and when F0MODE bit0 = 1, it is defined as in-process mode, and when bit0 = 0, it is defined as normal mode.
[0037]
First, it is checked from time to time whether there is a request to shift to the in-process mode (S21). When there is a request to shift to the in-process mode (Y in S21), F $ MODE F If FAC is already on (Y in S22), the process routine is exited as is, but F $ MODE F If FAC is not on (N in S22), it is determined that the mode is the transition from the normal mode to the in-process mode, and F $ MODE F The FAC is turned on, and the toner control correction value α stored in the EEPROM 40 is cleared to the default value (0) (S23). The process of step S23 is executed as a function of forced clearing means.
[0038]
On the other hand, when there is no request for shifting to the in-process mode (N in S21), it is checked as needed whether there is a request for shifting to the normal mode (S24). If there is a request for transition to the normal mode (Y in S24), F $ MODE F If FAC is not on (N in S25), the process routine is exited as is, but F $ MODE F If FAC is on (Y in S25), it is determined that the mode is the transition from the in-process mode to the normal mode, and F $ MODE F The FAC is turned off, and the toner control correction value α stored in the EEPROM 40 is cleared to the default value (0) (S26). The process of step S26 is executed as a function of forced clearing means.
[0039]
When the mode is switched in this way, the toner control correction value α stored in the EEPROM 40 is forcibly cleared to the default value (0), so that when a problem occurs in the factory assembly process, When the periphery of the process including the photosensitive member is confirmed using a factory jig as an evaluation, the value of the toner control correction value α is significantly different from the environment in which the original product process unit is mounted and normally used. It is possible to avoid such a problem that the toner control correction cannot be properly performed. Also, because it is forcibly cleared, you will never forget it.
[0040]
A second embodiment of the present invention will be described with reference to FIG. The same parts as those shown in the first embodiment are denoted by the same reference numerals, and description thereof is also omitted (the same applies to the following embodiments).
[0041]
In the present embodiment, depending on the use conditions in the in-process mode, a dip on the control board may be taken into consideration that the toner control correction value α may not be cleared even after returning from the in-process mode to the normal mode. The switch 47 (DIP SW1) is used as a selection means, and the dip switch 47 can arbitrarily select and set whether the forced clear operation is enabled or disabled. Here, the invalid mode in which the toner control correction value α cannot be forcibly cleared when DIPSW1 is set to ON, and the valid mode in which the toner control correction value α is forcibly cleared when DIP SW1 is set to OFF. To do.
[0042]
Referring to FIG. 8, in the process control described with reference to FIG. 7, before the process of clearing the toner control correction value α to 0 (S23, S26), the state of DIP SW1 is checked (S31, S32). If SW1 is not turned on (N in S31, N in S32), the processing (S23, S26) for clearing the toner control correction value α to 0 is performed as described in FIG. 7, but the DIP SW1 is turned on. If this is the case (Y in S31, Y in S32), the process of clearing the toner control correction value α to 0 (S23, S26) will be performed, and each of F $ MODE F Only the process of turning on the FAC (S33) or the process of turning off (S34) is performed, and the process routine is exited.
[0043]
Therefore, according to the present embodiment, it is possible to cope with a case where it is not desired to clear the toner control correction value α even if the mode is returned to the normal mode depending on the use condition in the in-process mode. For example, the inspection process in the in-process mode is temporarily completed and returned to the normal mode, but there are still cases where the inspection result is defective, the product is not shipped, and is used for a subsequent re-inspection. This can be dealt with when it is desired to use the value of the previous inspection stage as the value of α as it is.
[0044]
A third embodiment of the present invention will be described with reference to FIG. In the present embodiment, after the laser printer is put on the market as a product, the toner controllability value α should not be cleared by darkness. The toner control correction value α can be cleared on the condition that only a person knows the password input.
[0045]
This will be described with reference to the flowchart shown in FIG. Here, the case where the DIP SW2 in the DIP switch 47 is on is used as a trigger for forcibly clearing the toner control correction value α. In the market, if it becomes necessary to forcibly clear the toner control correction value α due to the replacement of the photosensitive member 1 or the like, the DIP SW2 is turned on (Y in S41). Then, the operation panel 30 is switched to the password input screen (S42) and waits for the password input (S43). If the password is input (Y in S43) and the password is correct (Y in S44), a clear process for setting the toner control correction value α to 0 is performed (S45). On the other hand, if the password is not input (N in S43) or the input password is not correct (N in S44), the clear process (S45) for setting the toner control correction value α to 0 is not executed. The process of Y in step S43 and the process of Y in S44 are executed as a function of the authentication means, and the process of step S45 is executed as a function of the forced clearing means.
[0046]
Therefore, according to the present embodiment, after the image forming apparatus is put on the market as a product, a clear process for setting the toner control correction value α to 0 is allowed only by a specific person such as a serviceman, and the toner control correction value α is no longer cleared by darkness.
[0047]
【The invention's effect】
According to the first aspect of the present invention, a predetermined pattern image is formed on the photosensitive member, and the toner control correction value α obtained based on the relationship between the potential of the pattern image and the photosensitive member background potential is stored in the nonvolatile memory. In the image forming apparatus used as one of the elements for storing and calculating the toner density, an in-process mode in which a factory jig is used for inspection instead of a product process unit including the photosensitive member in a process at the time of factory assembly A mode switching means for switching a normal mode which can be used in the market by mounting a product process unit, and the toner control correction value α stored in the nonvolatile memory when the mode is switched by the mode switching means. When the mode is switched by the mode switching means, the forced clearing means for returning the value to the default value is stored in the nonvolatile memory. The toner control correction value α can be forcibly cleared to the default value by the forcible clearing means, and since it is forcibly cleared, the toner control correction value α is used as it is without forgetting it. You can avoid that.
[0048]
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the forced clearing unit is stored in the non-volatile memory when the mode is switched from the in-process mode to the normal mode. Since the toner control correction value α is returned to the default value, for example, when the inspection is completed in the manufacturing process and the mode is switched from the in-process mode to the normal mode by the mode switching unit, the toner stored in the nonvolatile memory is stored. The control correction value α can be forcibly cleared to the default value by the forcible clearing means, and therefore, it can be avoided that the toner control correction value α in the in-process mode is used as it is in the normal mode.
[0049]
According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the forced clearing unit is stored in the nonvolatile memory when the normal mode is switched to the in-process mode. The toner control correction value α is reset to the default value, so that, for example, in order to perform an inspection in the factory assembly process, the mode is switched from the normal mode to the in-process mode. Then, the toner control correction value α stored in the nonvolatile memory can be forcibly cleared to the default value by the forcible clearing means, so that the toner control correction value α in the normal mode is used as it is in the in-process mode. It is possible to avoid being broken.
[0050]
According to the fourth aspect of the present invention, the image forming apparatus according to any one of the first to third aspects further includes a selection unit that enables or disables the operation of returning to the default value by the forced clearing unit. When the mode is switched, the toner control correction value α is forcibly cleared to the default value. However, it is desired to clear the toner control by setting the selection means to invalidate such an operation. If not, you can deal with it.
[0051]
According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the authentication means for enabling the operation of returning to the default value by the forced clearing means is provided. Since the toner control correction value α can be forcibly cleared only when the operation to return to the default value is enabled by means, the toner control correction value α must be cleared to darkness after it is put on the market as a product. This clearing operation can be avoided only by a specific person such as a serviceman.
[0052]
According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect, the authentication unit is a unit that validates the input of a password as a condition. It can be easily realized.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating a configuration example of a laser printer according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration example of the control system.
FIG. 3 is a schematic flowchart showing main control.
FIG. 4 is a schematic flowchart illustrating an example of interrupt processing.
FIG. 5 is a schematic view showing a process layout around a photosensitive member.
FIG. 6 is an explanatory diagram illustrating a predetermined pattern image example and an output level example.
FIG. 7 is a flowchart illustrating an example of processing control.
FIG. 8 is a flowchart showing an example of processing control according to the second embodiment of the present invention.
FIG. 9 is a flowchart showing an example of processing control according to the third embodiment of the present invention.
[Explanation of symbols]
1 Photoconductor
40 Nonvolatile memory
47 selection means
S23, S26 Forced clearing means
Y in S43, Y in S44 Authentication means
S45 Forced clearing means

Claims (6)

An element for forming a predetermined pattern image on the photoconductor, storing the toner control correction value α obtained based on the relationship between the potential of the pattern image and the photoconductor background portion potential in a non-volatile memory, and calculating the toner density. In an image forming apparatus used as one,
And mode switching means for switching a normal mode that allows for the mode and used by mounting the product process unit step using equipped with a factory jig instead of the product process unit comprising a pre-Symbol photoreceptor,
An image forming apparatus comprising: a forcible clearing unit that returns the toner control correction value α stored in the nonvolatile memory to a default value when the mode is switched by the mode switching unit.   2. The forced clearing unit returns the toner control correction value α stored in the nonvolatile memory to a default value when the mode is switched from the in-process mode to the normal mode. Image forming apparatus.   3. The forced clear means returns the toner control correction value α stored in the nonvolatile memory to a default value when the normal mode is switched to the in-process mode. The image forming apparatus described.   4. The image forming apparatus according to claim 1, further comprising a selection unit that enables or disables the operation of returning to the default value by the forced clear unit.   5. The image forming apparatus according to claim 1, further comprising an authentication unit configured to validate an operation of restoring the default value by the forced clear unit.   The image forming apparatus according to claim 5, wherein the authentication unit is a unit that validates a password as a condition.

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