JPH06194916A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device capable of properly controlling a toner concentration and a fixing temperature according to various kinds of image forming conditions by making the hard ware constitution of a process unit common. CONSTITUTION:The image forming device has a correction conditions generating means such as a ROM 32 generating the correcting conditions of a process speed, etc., participating in the correction of a concentration in the replenishment of toner 21 by a toner replenishing solenoid 9, a toner concentration sensor 22 measuring the concentration in the replenishment of the toner 21, an EEPROM 7 storing a series of toner concentration correction data corresponding to the level of the correcting conditions stepwise and a CPU 31 calculating a proper toner replenishment deciding level based on prescribed toner concentration correction data corresponding to the level of the correcting data conditions out of a series of the toner concentration correction data and comparing the toner replenishment deciding level with a toner sensor output level T0, to control the actuation of the toner replenishment solenoid 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic printer or an electrophotographic copying machine,
More specifically, the present invention relates to an image forming apparatus in which a process unit involved in image formation is detachably attached to the apparatus main body.

[0002]

2. Description of the Related Art Conventionally, various types of image forming apparatuses such as electrophotographic printers and electrophotographic copying machines have been known. Particularly, in recent years, printing paper has been considered in consideration of its convenience. Centered on the toner set containing the toner required for image formation on the image forming apparatus and the photoconductor drum that develops the image carrier with the toner supplied from the toner set according to the optical writing by the optical head unit of the apparatus main body. A drum unit and a drum unit are integrally formed as a process unit, and a process unit including the toner set and the drum set is detachably attached to the apparatus main body. .

Further, in a process unit used in this type of image forming apparatus, an EEPROM (electrically erasable programmable read only memory) which is a non-volatile memory capable of rewriting data at any time is further incorporated. There are things, this EEP
In the ROM, for example, a plurality of charging voltage data corresponding stepwise to the usage time of the photosensitive drum is stored in advance, and time data indicating the usage time of the photosensitive drum up to the present time is stored at any time. By storing the charging voltage data that matches the time data from the EEPROM and causing the main body control unit of the main body to perform a predetermined calculation, the quality of the photosensitive drum deteriorates with the increase of its use time and is appropriate for a long time. In order to form a different toner image, the charging voltage for forming the toner image on the photosensitive drum is adjusted to the optimum value.

In addition to this, for example, the above EEP
The ROM includes a fixing heater that heats the fixing roll in the fixing unit that measures the thermal fixing of the toner image formed on the photosensitive drum to the printing paper, and a thermistor that measures the heating temperature of the fixing roll by the fixing heater. The fixing temperature data indicating the ideal characteristics of both is stored, and the sensor output output from the thermistor during the fixing temperature control for controlling the temperature of the thermal fixing of the toner image is a value corresponding to the fixing temperature data. By making the main body controller of the apparatus main body determine whether or not it is present, the fixing unit normally functions during the fixing temperature control, and the toner image formed on the photosensitive drum is normally fixed on the printing paper. It is also performed to detect whether or not there is.

[0005]

By the way, the above EE
According to the image forming apparatus having the process unit having the built-in PROM, it is possible to correct the image forming conditions as described above. However, it is natural that the hardware configuration of the process unit is the apparatus. It is possible only when the specifications of the main unit are met. Therefore, it is not possible to mount the old process unit on the device main unit changed to the new specification and to use it, on the contrary, to replace the process unit changed to the new specification on the old device main unit. It is also impossible to mount and use. In other words, when considering the process unit as the main component, its hardware configuration is not standardized for the device main body that can be changed to various specifications, so compatibility with multiple device main bodies of arbitrary specifications can be obtained. However, this increases the production cost of each image forming apparatus and deteriorates its productivity. Of course, the above problem similarly occurs when the main body of the apparatus is considered instead of the process unit.

In connection with this, the process speed, which is the processing speed of image formation, is a major factor in determining the specifications of the apparatus main body. However, this process speed often differs depending on the model. As for the above, the inconvenience that the above-mentioned compatibility cannot be obtained occurs. Moreover, as in the former example described above, the EEPROM
When the charging voltage data is stored in, and the charging voltage for forming the toner image on the photosensitive drum is to be adjusted to the optimum value, the rotation speed is determined by the process speed of the main body of the adjustment. Since the process is uniformly performed corresponding to the photoconductor drum, if the process speed of the apparatus body changes, it is naturally impossible to adjust the charging voltage of the photoconductor drum to the optimum value.

On the other hand, as another problem different from this in nature, as shown in the crossover example above, fixing temperature data is stored in the EEPROM so that the fixing unit normally functions during fixing temperature control, and When trying to detect whether the toner image formed on the body drum is normally fixed on the printing paper, there is no adjustment of the fixing temperature according to the temperature and humidity of the toner that should be taken into consideration during the fixing temperature control. Some things have not been done. In addition, similar to this, for adjusting the toner density according to the temperature and humidity of the toner that should be taken into consideration when controlling the toner density for controlling the toner replenishment density to the photosensitive drum, and for measuring the toner density. Another problem is that the toner concentration is not adjusted at all according to the characteristic variation due to the individual difference of the toner concentration sensor incorporated in each process unit.

The present invention has been made on the basis of such an actual situation, and an object thereof is to make a hardware constitution of a process unit common to a plurality of apparatus main bodies having arbitrary specifications and to use a toner used. An object of the present invention is to provide an image forming apparatus capable of appropriately performing toner density control and fixing temperature control according to various image forming conditions such as state.

[0009]

According to a first aspect of the present invention, a process unit including at least a developing device for developing an image bearing member with toner is detachably attached to a main body of the device. The process unit includes a correction condition generating unit for generating a correction condition that is related to the density correction of the toner replenishment by the toner replenishing mechanism when the image carrier is developed by the developing device. Alternatively, the toner density sensor may be provided in any one of the apparatus main body and measures the toner replenishing density by the toner replenishing mechanism at the time of developing the image carrier by the developing device, and the degree of the correction condition generated by the correction condition generating means. The process unit has a non-volatile storage unit that stores a series of toner density correction data that correspond step by step. Of the series of toner density correction data stored in the non-volatile storage means, predetermined toner density correction data suitable for the degree of the correction condition generated from the correction condition generating means is read out, and based on the predetermined toner density correction data Calculating means for calculating an appropriate toner replenishment determination level when the image carrier is developed by the developing device,
The apparatus main body has control means for controlling the operation of the toner replenishing mechanism by comparing the toner replenishment determination level calculated by the arithmetic means with the digital conversion value of the sensor output from the toner concentration sensor. It is characterized by.

Here, in the case of the first aspect of the present invention, the above-mentioned correction condition generating means stores the process speed of the apparatus main body which is the correction condition, the temperature sensor for measuring the temperature of the process unit, and the process. A humidity sensor that measures the humidity of the unit, a detection unit that detects a variation in sensor output due to an individual difference of the toner concentration sensor, and a counting unit that counts the usage amount of the photoconductor drum in the developing device. The above-mentioned non-volatile storage means, as a series of toner density correction data corresponding to the above-mentioned correction conditions step by step, a series of process speed coefficient, a series of toner temperature coefficient, a series of toner humidity coefficient, and a series of toner. It is characterized in that it stores a sensor coefficient and a series of drum correction coefficients.

On the other hand, a second aspect of the present invention is an image forming apparatus in which a process unit including at least a developing device for developing an image carrier with toner is detachably attached to an apparatus main body. A correction condition generating means for generating a correction condition relating to temperature correction of toner fixing by a fixing unit after development of an image carrier by a developing device is provided in either the process unit or the apparatus main body. In addition, the process unit has a non-volatile storage means for storing a series of fixing temperature correction data corresponding stepwise to the degree of the correction condition generated by the correction condition generating means. Of a series of fixing temperature correction data stored in the means, a predetermined condition suitable for the degree of the correction condition generated by the correction condition generating means. A calculation unit that reads out the fixing temperature correction data and calculates an appropriate fixing control temperature after development of the image carrier by the developing device based on the predetermined fixing temperature correction data, and a fixing control temperature calculated by the calculation unit. A control unit for controlling the temperature of the fixing unit is provided in the main body of the apparatus.

Here, in the case of the second aspect of the present invention, the above-mentioned correction condition generating means stores the process speed of the apparatus main body which is the correction condition, the temperature sensor for measuring the temperature of the process unit, and A humidity sensor for measuring the humidity of the process unit, and further, the above-mentioned non-volatile storage means has a series of processes as a series of fixing temperature correction data corresponding stepwise to the above correction conditions. It is characterized by storing a speed coefficient, a series of toner temperature coefficients and a series of toner humidity coefficients.

[0013]

In the first aspect of the invention, the sensor output due to the process speed of the apparatus main body, the temperature of the process unit, the humidity of the process unit, and the individual difference of the toner concentration sensor, which are involved in the concentration correction of the toner replenishment by the toner replenishment mechanism. And the correction conditions such as the amount of the photosensitive drum used for developing the image carrier by the developing device,
It is generated from the correction condition generating means such as the storage means, the temperature sensor, the humidity sensor, the detecting means and the counting means. Then, the calculation means causes a series of process speed coefficients, a series of toner temperature coefficients, a series of toner humidity coefficients, a series of toner sensor coefficients, and a series of toner sensor coefficients corresponding to the degree of the correction conditions generated by the correction condition generation means in a stepwise manner. Among the series of toner density correction data such as the drum correction coefficient, predetermined toner density correction data suitable for the degree of the correction condition generated by the correction condition generating unit is read from the non-volatile storage unit for each correction condition. At the same time, the proper toner replenishment determination level at the time of developing the image carrier by the developing device is calculated based on the read predetermined toner density correction data, and further calculated by the control means by the calculation means. Digital conversion of toner replenishment judgment level and sensor output from toner concentration sensor DOO actuation of the toner supply mechanism is controlled are compared.

On the other hand, in the second aspect of the present invention, the correction conditions such as the process speed of the apparatus main body, the humidity of the process unit and the humidity of the process unit, which are involved in the temperature correction of the toner fixing by the fixing unit, are stored in the storage means and the temperature sensor. And a correction condition generating means such as a humidity sensor. Then, a series of fixing temperature correction data such as a series of process speed coefficient, a series of toner temperature coefficient, and a series of toner humidity coefficient corresponding to the degree of the correction condition generated by the correction condition generating means by the calculation means. Among these, the predetermined fixing temperature correction data suitable for the degree of the correction condition generated by the correction condition generating means is read from the non-volatile storage means for each correction condition, and the read predetermined fixing temperature An appropriate fixing control temperature after the development of the image carrier by the developing device is calculated based on the correction data, and the control unit controls the temperature of the fixing unit to the fixing control temperature calculated by the calculation unit.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings. First, FIG. 1 is a diagram schematically showing a configuration of an image forming apparatus according to an embodiment of the present invention.

As shown in the figure, this image forming apparatus is
The apparatus main body 1 is mechanically separated into a process unit 2 and a main body controller 3, and the process unit 2 and the main body controller 3 are connected to each other by a control line 4. ing.

Among them, the process unit 2 involved in the actual image formation includes a toner set (TS) 5 containing toner described later, which is necessary for image formation on the printing paper,
A drum set (DS) 6 centered on a photosensitive drum described later that develops an image bearing member with toner supplied from a toner set 5 in response to optical writing by an optical head unit described later of the apparatus main body 1 is provided. Further, in addition to these, an EEPROM 7 as a non-volatile storage means capable of rewriting data at any time is built in. And
Toner set 5, drum set 6 and EEPR
The process unit 2 including the OM 7 is configured to be attachable / detachable to / from the apparatus main body 1 so that the process unit 2 can be replaced with a new one according to the consumption state of the toner or the consumption state of the photosensitive drum. There is.

On the other hand, the process unit 2 is connected to the control line 4
The main body control unit 3 controlled via the CPU is provided with a CPU (central processing unit) described later, and this CPU reads, writes, and erases the contents of the EEPROM 7 in the preceding process unit 2 and other components. Is controlled.

Next, FIG. 2 is a diagram showing an example of a combination of the process unit 2 and the main body control unit 3 shown in FIG.

As shown in FIG. 1, PU2a, PU2b and PU2c of different specifications are prepared as the process unit 2 and the main body control unit 3 of the same specification is used as the main body control unit 3 described above. 3a, main body control section 3b and main body control section 3c
When the image forming apparatus is prepared, according to the configuration of the image forming apparatus, it is possible to use the combination shown by the mutual arrows in the drawing.
For example, the PU 2a can be used in combination with all of the main body control unit 3a, the main body control unit 3b, and the main body control unit 3c, and similarly, the PU 2
The main body control unit 3 of a and the PU 2 c of
It can be used in combination with all of the body control section 3b of a and the body control section 3c of a.

The differences in the specifications of PU2a, PU2b, and PU2c are mainly due to the aforementioned EEPROM.
The difference in the mechanical specifications of the other components except for 7, and the differences in the specifications of the main body control unit 3a, the main body control unit 3b, and the main body control unit 3c are mainly in the image forming processing speed. There is a difference in process speed.

Next, FIG. 3 is a diagram showing in detail the configuration of the image forming apparatus according to an embodiment of the present invention. As shown in the figure, this image forming apparatus is configured to have the process unit 2 and the main body control section 3 as described above, and in addition to these, the apparatus excluding the process unit 2 and the main body control section 3 A fixing unit 8 involved in actual image formation is provided in a part of the main body 1 together with the process unit 2, and further, as a toner replenishment mechanism involved in control of the process unit 2 by the main body controller 3. A toner replenishing solenoid 9, a motor unit 10 as a rotating mechanism such as a photosensitive drum, and an optical head unit 11 having an optical writing head such as a plurality of light emitting diodes are provided. The fixing unit 8 includes a fixing heater 81 that heats a fixing roll (not shown), and a thermistor 82 that measures a heating temperature of the fixing roll by the fixing heater 81. Of these, the thermistor 82 is adapted to give its sensor output to the main body control section 3.

Here, the process unit 2 uses the above-mentioned E
In addition to the EPROM 7, a toner 21 required for image formation, a toner density sensor 22 for measuring the density of replenishment of the toner 21, and correction conditions relating to correction of the density of replenishment of the toner 21 and temperature correction of fixing. The temperature sensor 23 as a correction condition generating means for measuring the temperature of the process unit 2 (which is also the temperature of the toner 21) and the process serving as the correction condition involved in the density correction of the replenishment of the toner 21 and the temperature correction of the fixing. A humidity sensor 24 as a correction condition generating means for measuring the humidity of the unit 2 (which is also the humidity of the toner 21), and a photosensitive drum 25 for developing the image carrier with the toner 21 in response to optical writing by the optical head unit 11. And is configured. The toner concentration sensor 22 and the temperature sensor 23 among them
The humidity sensor 24 and the humidity sensor 24 give respective sensor outputs to the main body controller 3.

On the other hand, the main body control section 3 is configured to have a CPU 31 as an arithmetic means and a control means, as mentioned in the description of FIG. 1 above, and further, a processing program executed by the CPU 31. At the same time, the ROM, which is a storage unit as a correction condition generation unit, stores the process speed of the apparatus main body 1 which is a correction condition involved in the density correction of the toner 21 replenishment and the temperature correction of the fixing.
(Read-only memory) 32, timer 33 which is a calendar clock, and thermistor 8 in the fixing unit 8.
2. Toner concentration sensor 2 in process unit 2
2. A / D conversion (analog / digital conversion) of sensor outputs respectively given from the temperature sensor 23 and the humidity sensor 24, and an A / D converter 34 for giving the digital converted value to the CPU 31, various buffers 35, 36, and Three
It is configured to have 7.

That is, the CPU 31 forming the center of the main body control section 3 is based on the processing program stored in the ROM 32, and the EEPRO in the process unit 2 is executed.
In addition to reading, writing and erasing the contents of M7,
While controlling the operation of the motor unit 10 to rotate the fixing roll in the fixing unit 8 and the photoconductor drum 25 in the process unit 2, the fixing unit 8 is heated via the driver 35 to heat the rotating fixing roll. In addition to energizing the fixing heater 81, the print data for sequentially performing optical writing on the photosensitive drum 25 which is also rotated is given to the optical head unit 11 via the driver 36, and further the toner is supplied via the driver 37. The operation of the supply solenoid 9 is controlled to supply the toner 21 in the process unit 2 to the surface of the photoconductor drum 25. The A / D converter 3
4 T ₀ shown given to CPU31 is a toner sensor output level is a digital conversion value corresponding to the sensor output outputted from the toner density sensor 22 in the process unit 2, for example, particularly in the process unit 2 By setting the toner sensor output level T ₀ when the toner 21 is sufficiently replenished to the surface of the photosensitive drum 25 as a reference value, the CPU 31
The detection unit can serve as a correction condition generation unit that detects a variation in sensor output due to individual differences of the toner concentration sensor 22 that is a correction condition related to the density correction of the toner 21 replenishment.

Next, FIG. 4 is a diagram showing a memory map of the EEPROM 7 shown in FIGS. 1 and 3. As shown in the figure, in the EEPROM 7, the number-of-prints counter area 71, the process speed coefficient storage area 72, the toner temperature coefficient storage area 73, and the toner humidity coefficient storage area 7 are stored.
4, a toner sensor coefficient storage area 75 and a drum correction coefficient storage area 76 are secured.

Among these, in the print number counter area 71, a count as a correction condition generating means for counting the usage amount of the photosensitive drum 25 in the process unit 2 which is a correction condition related to the density correction of the replenishment of the toner 21 A print number counter DCNT, which is a means, is set. The CPU 31 of the main body control unit 3 forms the image on the printing paper with the value of "0" set at the start of use of the process unit 2 (not used). By incrementing by +1 for each time, the number of print sheets on which the image is formed is counted.

On the other hand, the process speed coefficient storage area 72
Is a series of process speed coefficients PSKn (n is an address shown in the figure, which is stored in the ROM 32 of the main body control unit 3 as a series of toner density correction data corresponding stepwise to the degree of the process speed of the apparatus main body 1. AD
It is a natural number that increases according to the value of RS. same as below)
Similarly, a series of process speed coefficients PSKn ′ as a series of fixing temperature correction data corresponding stepwise to the degree of the process speed of the apparatus body 1 are written in advance by a writing device (not shown) (the same applies hereinafter). , This is constantly stored. Here, as an example, the process speed coefficients PSK1 and PSK1 ′ are PSK2 and PSK2 ′ when the process speed of the main body control unit 1 is 6 ppm (print / minute).
Has a coefficient of 8 ppm, PSK3 and PSK
A coefficient at 10 ppm is stored in 3 '.

In the toner temperature coefficient storage area 73,
A series of toner temperature coefficients TKn as a series of toner concentration correction data corresponding to the degree of temperature of the process unit 2 measured by the temperature sensor 23 in the process unit 2, and the degree of temperature of the process unit 2 as well. A series of toner temperature coefficients TKn ′ as a series of fixing temperature correction data corresponding to stepwise are stored constantly. In this case, for example, the toner temperature coefficient T
K1 and TK1 'have coefficients when the temperature of the process unit 2 is 5 ° C, and TK2 and TK2' have 6 °.
The coefficient at C is stored in TK3 and TK3 'at 7 ° C.

Similarly, in the toner humidity coefficient storage area 74, a series of toner density correction data, which is measured by the humidity sensor 24 in the process unit 2 and corresponds stepwise to the degree of humidity of the process unit 2, is stored. Similarly, the toner humidity coefficient HKn and a series of toner humidity coefficients HKn 'as a series of fixing temperature correction data corresponding to the degree of humidity of the process unit 2 are stored constantly. Also in this case, for example, the toner humidity coefficients HK1 and HK1 'are set to the process unit 2
Coefficient when the humidity of 20% RH is HK2 and HK
In 2 ', the coefficient at 22% RH is HK3 and HK
The coefficient at 24% RH is stored in 3 '.

Further, in the toner sensor coefficient storage area 75, a series of toner density corrections corresponding to the degree of variation in sensor output due to individual difference of the toner density sensor 22 detected by the CPU 31 in the main body control unit 3 are stepwise corrected. A series of toner sensor coefficients TSKn (T
SK1) are constantly stored. In this case, as described above, the toner 21 in the process unit 2
The toner sensor output level T ₀ when the surface of the photosensitive drum 25 is sufficiently replenished may be used as the reference value.

Then, the drum correction coefficient storage area 76 is stepwise to the extent of the usage amount of the photosensitive drum 25 in the process unit 2 which is determined by the printing number counter DCNT set in the preceding printing number counter area 71. A series of drum correction coefficients DCKn as a series of toner density correction data corresponding to is stored constantly.
In this case, for example, the drum correction coefficient DCK1 is a coefficient when the number of printed sheets counter DCNT is 1 to 500 (sheets), the coefficient when DCK2 is 501 to 1000 (sheets), and the coefficient when DCK3 is 1001. The coefficients for up to 1500 (sheets) are stored.

Next, the operation of the image forming apparatus configured as above will be described. First, when performing the density correction of the replenishment of the toner 21, the CPU 31 in the main body control unit 3
The data indicating the process speed peculiar to the device main body 1 is R
While reading from the OM 32, variations in sensor output due to individual differences of the toner concentration sensor 22 unique to the process unit 2 are detected. The CPU 31 also controls the temperature sensor 23 and the humidity sensor 2 in the process unit 2.
4 digitally converted values of the current sensor output A /
The current value of the print number counter DCNT indicating the usage amount of the photosensitive drum 25 in the process unit 2 is read from the print number counter area 71 in the EEPROM 7 while being fetched from the D converter 34.

Then, the CPU 31 has a predetermined process speed coefficient P adapted to the degree of the data indicating the obtained process speed and the sensor output.
SKn, toner temperature coefficient TKn, toner humidity coefficient HK
n, toner sensor coefficient TSKn and drum correction coefficient D
CKn is the process speed coefficient storage area 72, toner temperature coefficient storage area 73, toner humidity coefficient storage area 74, toner sensor coefficient storage area 75 in the EEPROM 7.
Further, the toner replenishment determination level Ts, that is, Ts = PSKnTKnHKnDCKnTs ₀ (Equation 1) is calculated from the drum correction coefficient storage area 76 and the respective coefficients. However, Ts ₀ is a toner replenishment level reference value, and is a unique value obtained by referring to a toner sensor coefficient TSKn indicating a variation in sensor output due to individual difference of the toner concentration sensor 22.

Here, to give a concrete example, the process speed of the apparatus main body 1 is 10 ppm, the current temperature of the process unit 2 is 6 ° C., the current humidity of the process unit 2 is 20% RH, and the number of printed sheets counter DCNT. of if the current value is 825 (sheets), the toner replenishing determination level Ts according to equation 1 described above becomes Ts = PSK3 · TK2 · HK1 · DCK2 · Ts 0.

Then, the CPU 31 in the main body control unit 3
Is the toner replenishment determination level Ts calculated in this way,
The toner sensor output level T ₀ that is a digital conversion value corresponding to the sensor output output from the toner concentration sensor 22 in the process unit 2 is compared, and this toner sensor output level T ₀ becomes smaller than the toner replenishment determination level Ts. In the case of (T ₀ <Ts), the operation of the toner replenishing solenoid 9 is controlled via the driver 37 to replenish the developing device with the toner 21 in the process unit 2. The toner density control according to the various image forming conditions can be properly performed.

On the other hand, in the case of correcting the fixing temperature of the toner 21, the CPU 31 in the main body control section 3
The data indicating the process speed peculiar to the device main body 1 is R
The digital conversion values of the current sensor outputs of the temperature sensor 23 and the humidity sensor 24 in the process unit 2 are read out from the OM 32, and the A / D converter 3 is also provided.
Take in from 4.

Then, the CPU 31 has a predetermined process speed coefficient P adapted to the obtained data indicating the process speed and the degree of the sensor output.
SKn ′, toner temperature coefficient TKn ′ and toner humidity coefficient HKn ′ are read from the process speed coefficient storage area 72, toner temperature coefficient storage area 73 and toner humidity coefficient storage area 74 in the EEPROM 7, respectively.
Further, the fixing control temperature Tf, that is, Tf = PSKn ′ · TKn ′ · HKn ′ · Tf ₀ (Equation 2) is calculated from these respective coefficients. Note that Tf ₀ is, for example, the EEPROM 7
Is a fixing temperature reference value that is constantly stored in an arbitrary storage area, and is unique to the fixing temperature based on a predetermined process speed of a predetermined apparatus body 1 and a predetermined temperature and humidity of a predetermined process unit 2. Is the value of.

Here, to give a concrete example, when the process speed of the apparatus main body 1 is 8 ppm, the current temperature of the process unit 2 is 5 ° C., and the current humidity of the process unit 2 is 24% RH, , the fixing control temperature Tf by equation 2 described above becomes Tf = PSK2 '· TK1' · HK3 '· Tf 0.

Then, the CPU 31 in the main body control section 3
Is energized to the fixing heater 81 in the fixing unit 8 via the driver 35 so that the temperature of the fixing roll in the fixing unit 8 is set to the fixing control temperature Tf calculated in this way. The fixing temperature control can be properly performed according to various image forming conditions such as the toner state.

The embodiment of the present invention has been described above. In particular, the density correction for replenishing the toner 21 is performed with reference to the value of the print number counter DCNT in the EEPROM 7, as shown in the embodiment. It is also possible to use the timer clock 33. That is,
The year, month, day, and hour data at the start of use of the process unit 2 is stored in an arbitrary storage area of the EEPROM 7, and the CPU 31 stores the year, month, day, and hour data at the start of use in the timer 33. From the calendar data, and the time data after the subtraction may be used as a substitute for the print number counter DCNT. in this case,
Since the elapsed time of the toner 21, the photosensitive drum 25, and the like from the start of use of the process unit 2 is accurately calculated, the replenishment concentration of the toner 21 that takes into consideration the change with time of the characteristics of the photosensitive drum 25 and the like is taken. Can also be corrected.

[0042]

As described above in detail, according to the first aspect of the present invention, the calculating means is based on the predetermined toner density correction data adapted to the degree of the correction condition generated from the correction condition generating means. An appropriate toner replenishment determination level at the time of developing the image carrier by the developing device is calculated, and the calculated toner replenishment determination level and the digital conversion value of the sensor output from the toner density sensor are calculated by the control means. By comparison, the operation of the toner replenishing mechanism is controlled, and according to the second aspect of the present invention, the calculation means corrects a predetermined fixing temperature that matches the degree of the correction condition generated by the correction condition generating means. An appropriate fixing control temperature after development of the image carrier by the developing device is calculated based on the data, and the calculated fixing control temperature is further calculated by the control means. The temperature of the fixing unit is to be controlled, so that various toner concentration control and the fixing temperature control in accordance with image forming conditions such as the condition of the toner to be used are performed properly.

Since the process speed of the apparatus main body is set as the correction condition generated by the correction condition generating means, the hardware configuration of the process unit is made common to a plurality of apparatus main bodies having arbitrary specifications. As a result, it is possible to easily respond to changes in the specifications of the main body of the apparatus and version upgrades, so that high compatibility can be obtained, and along with this, the production cost of individual image forming apparatuses is reduced. And, the productivity will be improved.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a configuration of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a combination of the process unit and the main body control unit shown in FIG. 1 in the case where three types having different specifications are facilitated.

FIG. 3 is a diagram showing in detail the configuration of an image forming apparatus according to an embodiment of the present invention.

FIG. 4 is a diagram showing a memory map of the EEPROM shown in FIGS. 1 and 3;

[Explanation of symbols]

 1 Device Main Body 2 Process Unit 3 Main Body Control Unit 7 EEPROM 8 Fixing Unit 9 Toner Supply Solenoid 21 Toner 22 Toner Density Sensor 23 Temperature Sensor 24 Humidity Sensor 25 Photosensitive Drum 31 CPU 32 ROM 71 Print Number Counter Area 72 Process Speed Coefficient Storage Area 73 toner temperature coefficient storage area 74 toner humidity storage area 75 toner sensor coefficient storage area 76 drum correction coefficient storage area

Claims (10)

[Claims] 1. An image forming apparatus comprising a process unit including at least a developing device for developing an image bearing member with toner, which is detachably attached to an apparatus main body. Means, a toner sensor provided in the process unit for detecting the toner concentration, and a series of toner concentrations provided in the process unit and corresponding stepwise to the degree of the correction condition generated by the correction condition generating means. Non-volatile storage means for storing correction data, and the correction condition generated from the correction condition generation means out of the series of toner density correction data provided in the apparatus main body side and stored in the non-volatile storage means. Of the predetermined toner density correction data that matches the degree of A calculation unit for calculating an appropriate toner replenishment determination level when the image carrier develops the image carrier, and a digital representation of the toner replenishment determination level calculated by the calculation unit and the sensor output output from the toner concentration sensor. An image forming apparatus, comprising: a control unit for controlling the operation of the toner replenishing mechanism by comparing the converted value with the apparatus main body. 2. The image forming apparatus according to claim 1, wherein the correction condition generating unit is a storage unit that stores a process speed of the apparatus main body which is the correction condition. 3. The image forming apparatus according to claim 1, wherein the correction condition generation unit is a temperature detection unit that measures the temperature of the process unit that serves as the correction condition. 4. The image forming apparatus according to claim 1, wherein the correction condition generation unit is a temperature detection unit that measures the temperature of the process unit that serves as the correction condition. 5. The image forming apparatus according to claim 1, wherein the correction condition generation unit is a detection unit that detects a variation in the sensor output due to an individual difference of the toner density sensor serving as the correction condition. 6. The correction condition generating means is a counting means for counting the usage amount of the photosensitive drum in the process unit, which serves as the correction condition.
The image forming apparatus described. 7. An image forming apparatus comprising a process unit including at least a developing device for developing an image bearing member with toner in a detachable manner with respect to an apparatus main body. Means, a non-volatile storage means provided in the process unit for storing a series of fixing temperature correction data corresponding to the degree of the correction condition generated from the correction condition generating means in a stepwise manner, And a predetermined fixing temperature correction data suitable for the degree of the correction condition generated from the correction condition generating means out of the series of fixing temperature correction data stored in the non-volatile storage means is read. Calculation for calculating an appropriate fixing control temperature after development of the image carrier by the developing device based on predetermined fixing temperature correction data An image forming apparatus, characterized in that the apparatus main body has means and control means for controlling the temperature of the fixing unit to the fixing control temperature calculated by the arithmetic means. 8. The image forming apparatus according to claim 7, wherein the correction condition generation unit is a storage unit that stores a process speed of the apparatus main body which is the correction condition. 9. The image forming apparatus according to claim 7, wherein the correction condition generation unit is a temperature detection unit that measures the temperature of the process unit that serves as the correction condition. 10. The image forming apparatus according to claim 7, wherein the correction condition generation unit is a humidity detection unit that measures the humidity of the process unit that serves as the correction condition.