JP2012042500A - Fixing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device capable of simply discriminating a heater power distribution configuration in the fixing device.SOLUTION: The start of warm-up is instructed with respect to a fixing heater (step S4). It is determined whether or not heater configuration information is stored in a memory (step S6). When it is determined that the heater configuration information is stored in the memory in the step S6, a CPU turns on all the fixing heaters (step S14). Then, it is determined whether or not predetermined temperature or more is obtained (step S16). When it is determined that the predetermined temperature or more is obtained, it is determined that power is high (two-heater configuration) (step S18). When it is determined that the predetermined temperature or more is not obtained, it is determined that the power is low (three-heater configuration) (step S26).

Description

  The present invention relates to an electrophotographic fixing device and an image forming apparatus including the same.

  2. Description of the Related Art Conventionally, in a fixing device in an electrophotographic recording apparatus, the temperature detected by a thermistor (temperature detecting means) disposed near the fixing roller and the temperature of the fixing temperature are used to reduce the temperature ripple of a fixing member such as a fixing roller. Using the difference and the amount of change in the detected temperature of the thermistor within a certain period of time as a decision factor, the lighting time and the light-off time of the fixing heater built in the fixing roller are set. Control is performed to control the fixing member to the fixing temperature.

  When performing such control, since the lighting period and the extinguishing period are usually set for a certain voltage, the setting of the lighting time and the extinguishing time is deviated from the target value in an area where the voltages are slightly different. In that case, there is a possibility that the temperature ripple of the fixing member becomes large, or a problem such as a decrease in fixing temperature occurs. In order to correct this, a voltage detection means is provided, and the setting is changed according to the detected voltage. Or measures such as changing the setting of the lighting / extinguishing time for each region at the time of factory shipment have been taken.

  In such countermeasures, there is a problem that the operation of setting the lighting / extinguishing time according to the region where the voltage is different is complicated, leading to an increase in cost.

  In Japanese Patent Laid-Open No. 2000-330418, a temperature detecting means for detecting the temperature of the fixing member, a timer for measuring the lighting period and the extinguishing period of the fixing heater, and a plurality of types corresponding to changes in the input voltage to the fixing heater. An on / off duty type storage means in which the on / off duty type of the fixing heater is stored in advance, and based on the time required for the temperature of the fixing member to increase by a predetermined temperature difference by energizing the fixing heater when the power is turned on, Select or set one of multiple types of on / off duty types, and use the on / off duty type to turn on / off the fixing heater based on the temperature difference between the current temperature of the fixing member and the fixing temperature and the amount of change in the detected temperature over a certain period of time. Controls to solve problems and automatically turns on in response to changes in input voltage at low cost It discloses a fixing device capable of setting the off time.

  Conventionally, in the temperature control of the fixing device, the fixing heater is turned on when the temperature of the fixing device is lower than the target temperature and turned off when the temperature is higher, or the fixing roller is fixed. In order to reduce the on / off frequency of the fixing heater in order to reduce the temperature ripple of the member, hysteresis temperature control that turns on the fixing heater when the temperature is lower than the target temperature range and turns off when the temperature is higher is more commonly used. ing.

  Among fixing devices using such temperature control, for example, there are image forming apparatuses of the same series depending on the destination of the shipping region, for example, but the number of fixing heaters is different and the power distribution configuration of the fixing heaters is different. To do.

  For example, in a device for Europe with flicker regulations, lighting of the heater during temperature control during normal image formation is reduced to 1/3 of the AC half wave of the commercial power source in order to suppress flicker during heater lighting. AC half-wave cycle control is performed such that the lamp is lit at a cycle of 1/2 cycle.

  In general, an apparatus for fixing various types of paper is generally configured with two heaters, ie, a small size heater and a large size end light distribution heater. During heating up, the two fixing heaters are controlled to be fully lit in order to perform a short warm-up, and AC half-wave cycle control is performed during standby or during normal temperature control during image formation.

  As a result, the execution power during normal temperature control is 1/3 to 2/3 of that during warm-up, so that not only the flicker value is suppressed but also the effective power during normal temperature control is suppressed to an appropriate value. In other words, the temperature ripple of the fixing member is reduced.

  In addition, AC current can be regulated by implementing AC half-wave cycle control even in an area where commercial power supply current 15A is regulated. With the above configuration, flicker regulation can be achieved while minimizing the cost with a minimum number of heaters. , Current regulation, temperature ripple, warm up can be achieved.

JP 2000-330418 A

  On the other hand, in the past, the AC half-wave cycle control is performed in an environment where the supply situation of commercial power is poor, and the fixing device is connected to the power supply of a lighting device such as a fluorescent lamp connected to the same power supply system. There was a problem that the lighting equipment flickers due to the influence of the power supply fluctuation that cycle-controls the AC half-wave at about 20 Hz.

  In particular, the influence is large in regions where the power supply voltage is low, and in response to such a situation, the number of fixing heaters has been increased by one. That is, a heater dedicated to warm-up is provided, and the heater for normal temperature control is a total of three heaters of two configurations of a small size heater and a large size end light distribution heater.

  In this system, the total power of the two heaters, the warm-up heater and the temperature control heater, achieves a short warm-up as the same power as that in the configuration for performing the AC half-wave cycle control, and two heaters are used during normal temperature control. Is controlled so that the effective power at that time is equivalent to the effective power when the AC half-wave cycle control is performed, and the power of the two heaters is distributed to restrict current regulation, temperature ripple, and internal environment. Is to eliminate.

  In the above configuration, since there is a cost disadvantageous factor for configuring one heater more, even in the case of the same commercial power supply voltage in the same shipping region, a cost-oriented configuration is used, or the commercial power source is the same system. It is possible to select whether or not a configuration that places emphasis on the suppression of obstacles to the external lighting device is selected.

  Therefore, in a fixing system having a difference in heater power distribution as described above, it is necessary to switch the control by determining whether the heater is fully lit or AC half-wave cycle control for each configuration with different heater power distribution. It was.

  In that case, setting the control orientation at the time of shipment from the factory as in the prior art takes a long time for the work and has a large loss in terms of management.

  Further, although there has been a method of identifying the fixing device orientation by giving an identification signal to the main body of the fixing mounting or image forming apparatus, there has been a problem that the loss is large in terms of management due to an increase in the combination of identification signals.

  In Patent Document 1 described above, the temperature rise gradient is detected and an on / off duty table is selected. For this, in the fixing device having the same power configuration, the optimum table when the power supply voltage is somewhat different is used as the power supply. Since the difference in temperature rise gradient is determined by changing the voltage, the power distribution configuration cannot be detected for the same power supply voltage, because the power supply voltage cannot be changed for different heater power distribution configurations. It wasn't something that could be done. In addition, since it was to select which to change depending on the difference in power supply voltage from the on-off duty type in a long cycle, it can not cope with control that chooses full lighting or AC half-wave cycle control, For example, when a long-cycle on / off duty type control is selected for a fixing device that requires AC half-wave cycle control, problems such as increased temperature ripple or exceeding the flicker regulation value occur. obtain.

  In Patent Document 1, the temperature rise gradient is determined when the power supply voltage is changed when the power is first turned on after the fixing device is installed. However, there is a difference in the power distribution configuration itself of the fixing device. In this case, for example, when all the heaters are fully lit, the total power is set to be the same, so that there is a problem that a difference in temperature increase gradient does not appear in the first place. Furthermore, performing the detection control only when the power is first turned on after the fixing device is installed requires a predetermined work, and there is a problem that a work loss occurs.

  SUMMARY An advantage of some aspects of the invention is that it provides a fixing device and an image forming apparatus that can easily determine a heater power distribution configuration in a fixing device. And

  A fixing device according to an aspect of the present invention is a fixing device that fixes toner transferred to a recording sheet, and includes a fixing member and a plurality of heaters having different power distributions for heating the fixing member to a predetermined fixing temperature. A heater unit configured to detect a temperature of the fixing member, and a control unit that performs lighting control of the heater unit, and the controller detects a temperature increase value of the fixing member by the temperature detection unit. Detection is performed, and lighting control corresponding to the difference in power distribution of the heater unit is executed based on the detection result.

  Preferably, the control unit performs full lighting control of all the heaters after the warm-up is completed, detects a temperature increase value of the fixing member by the temperature detection unit, and determines a difference in power distribution of the heater unit based on the detection result. The lighting control corresponding to is executed.

  In particular, the control unit stores the detection result in a memory, and the control unit performs full lighting control of all the heaters after the warm-up is completed, and detects the temperature rise value of the fixing member by the temperature detection unit. Before, it is determined whether or not the detection result is stored in the memory, and when the detection result is stored in the memory, it corresponds to the difference in power distribution of the heater unit based on the detection result Execute lighting control.

  Preferably, when the temperature detection unit determines that the temperature rise value of the fixing member is equal to or greater than a predetermined value, the control unit performs AC half-wave cycle control on the heater unit.

  Preferably, when the temperature detection unit determines that the temperature increase value of the fixing member is less than a predetermined value, the control unit performs full lighting control on the heater unit.

  An image forming apparatus according to an aspect of the present invention includes an image forming unit that forms a toner image and transfers the toner image onto the recording paper, and the fixing device described above.

  A fixing device according to an aspect of the present invention detects a temperature rise value of the fixing member by a temperature detection unit, and executes lighting control corresponding to a difference in power distribution of the heater unit based on a detection result. Therefore, it is possible to easily determine the heater power distribution configuration, and it is possible to perform heater lighting control suitable for the power distribution configuration of the fixing heater.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. It is a figure explaining the structure of the recording part 200 according to embodiment of this invention. It is a figure explaining the structure of the fixing device according to embodiment of this invention. It is a figure explaining the fixing device of a 2 heater structure. FIG. 5 is a diagram illustrating effective power in the fixing device having the two-heater configuration of FIG. 4. It is a figure explaining the fixing device of a 3 heater structure. It is a figure explaining the effective electric power in the fixing device of the 3 heater structure of FIG. FIG. 5 is a diagram illustrating effective power in the fixing device having the configuration of the two heaters of FIG. 4 according to the embodiment of the present invention. It is a figure explaining the effective electric power in the fixing device of the structure of 3 heaters of FIG. 6 according to embodiment of this invention. It is a figure explaining transition of the temperature of the heating member of the fixing device according to the embodiment of the present invention. It is a flowchart explaining the flow of the process which controls heater lighting corresponding to the difference in the electric power distribution of the fixing heater of the fixing device according to the embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same.

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention.
Referring to FIG. 1, an image forming apparatus 100 includes a CPU (Central Processing Unit) 23, a ROM (Read Only Memory) 24, a RAM (Random Access Memory) 25, a communication unit 26, a reading unit 27, an operation display unit 28, a timer. The thermistor 11, the A / D conversion unit 15, the fixing heater 10, the output port 17, the drive control unit 18, the laser control unit 19, and the like constitute the recording unit 200.

  The ROM 24 stores a basic processing program for the image forming apparatus 100, a temperature control program for the fixing heater 10, data necessary for executing these programs, and the like.

  The CPU 23 (control means) controls each part of the image forming apparatus 100 while using the RAM 25 as a work memory based on a program in the ROM 24 to perform basic processing as the image forming apparatus 100 and temperature control processing of the fixing heater 10.

  The RAM 25 is used as a work memory for the CPU 23. The RAM 25 is also used as a page memory in which write data for one page recorded in the recording unit 200 is expanded. That is, a page memory area is formed in the RAM 25, and one page of write data recorded and output by the recording unit 200 is developed by the CPU 23 into the page memory area of the RAM 25 and output by the CPU 23 to the laser control unit 19. The

  For example, a public telephone line is connected to the communication unit 26 and performs automatic call origination / incoming call processing, facsimile communication procedure execution processing, modulation / demodulation processing, image data compression / reproduction processing, and the like.

  The reading unit 27 is composed of, for example, an image scanner using a CCD, and the image scanner scans an original and reads an image surface of the original with a predetermined resolution.

  The operation display unit 28 includes various operation keys such as a numeric keypad and a start key, and also includes a display (for example, a liquid crystal display), and various commands such as a transmission operation are input from the operation keys. Are displayed, and various information notified to the operator from the image forming apparatus 100 is displayed. In particular, after the apparatus is installed, when a predetermined operation key is pressed when the power is turned on for the first time, a command signal for instructing a setting process for a lighting / extinguishing period, which will be described later, is sent to the CPU 23 and input.

  The timer 22 includes an oscillation circuit, a frequency dividing circuit, and the like, and outputs a time measurement result to the CPU 23. The CPU 23 controls each part of the image forming apparatus 100 based on the timing of the timer 22.

  As the recording unit 200, a known electrophotographic recording apparatus is used, and is configured as shown in FIGS.

FIG. 2 is a diagram illustrating the configuration of the recording unit 200 according to the embodiment of the present invention.
Referring to FIG. 2, the recording unit 200 includes a photosensitive member 13, a cleaning unit 4, a charge removal unit 5, a charging unit 6, an exposure unit 7, a development unit 8, a transfer unit 14, a fixing roller 9, a pressure roller 3, a discharge roller. The photosensitive member 13 is composed of a paper roller 2 and the like, and is driven to rotate by a plurality of conveying rollers 12.

  In the recording unit 200, an electrostatic latent image is formed on the photosensitive member 13 uniformly charged by the charging unit 6 by modulating the laser based on the image data, and the exposure unit 7 forms the electrostatic latent image. The developing unit 8 develops toner by attaching it to the photosensitive member 13. The toner adhering to the photosensitive member 13 is transferred from a recording paper cassette (not shown) to the recording paper conveyed to the transfer unit 14, and the recording paper adhering the toner is conveyed to the fixing roller 9 and the pressure roller 3.

  After the transfer, the photosensitive member 13 has the residual toner removed by the cleaning unit 4, neutralized by the neutralizing unit 5, charged by the charging unit 6, and waits for the next electrostatic latent image forming step.

FIG. 3 is a diagram illustrating the configuration of the fixing device according to the embodiment of the present invention.
Referring to FIG. 3, the fixing roller 9 has a built-in fixing heater 10, a thermistor 11 is provided in contact with the outer periphery thereof, and a separation claw 1 for separating the recording paper after fixing is provided. ing.

  After the fixing roller 9 is heated and held at a predetermined temperature by the fixing heater 10 built in the fixing roller 9, the toner is fixed on the recording paper, and then the recording paper is discharged to a discharge tray (not shown) by the discharge roller 2. To do.

  Referring again to FIG. 1, the thermistor 11 (temperature detection means) detects the temperature of the fixing roller 9 and outputs an analog temperature detection signal to the A / D converter 15. The A / D converter 15 converts the analog temperature detection signal input from the thermistor 11 into a digital temperature detection signal and outputs the digital temperature detection signal to the CPU 23 via the bus. That is, the thermistor 11 is disposed in the vicinity of the fixing roller, and the CPU 23 acquires the temperature of the fixing roller 9 based on this temperature detection signal.

  The fixing heater 10 generates heat and heats the fixing roller 9 by turning on / off a power supplied from an external power source (not shown) in response to a turn-on signal and a turn-off signal input from the output port 17.

  The drive control unit 18 controls the operation of the drive part of the recording unit 200 based on a command from the CPU 23.

  The laser control unit 19 performs drive control of a laser light emitting unit (not shown) based on write data (image data) transferred from the RAM 25, and performs laser modulation control corresponding to the write data.

  According to such a configuration, the image forming apparatus 100 compresses the image data of the document read by the reading unit 27 in the communication mode by a predetermined compression method, and then transmits the image data to the other party. After being expanded in the page memory area of the RAM 25, it is transmitted to the recording unit 200 and output to the recording paper.

  Further, the image forming apparatus 100 develops the image data of the document read by the reading unit 27 in the copy mode in the page memory area of the RAM 25 for each page, and then transmits the image data to the recording unit 200 and outputs it to the recording paper. When outputting image data in the recording unit 200, the fixing roller 9 is controlled to a suitable fixing temperature by controlling the energization to the fixing heater 10.

  Next, in the fixing device according to the embodiment of the present invention, a configuration having a difference in the heater power distribution configuration will be described.

FIG. 4 is a diagram illustrating a fixing device having a two-heater configuration.
Referring to FIG. 4, here, a fixing device having a two-heater configuration that focuses on meeting costs and flicker regulations is shown.

  As an example, it is assumed that the center heater 10A is an 800W heater, and the end heater 10B has a 500W heater configuration as an end light distribution in order to heat the end of a large size sheet.

  It is assumed that at least one thermistor 11 for measuring the temperature of the heated fixing member and maintaining a predetermined temperature is installed in the fixing device.

  The temperature of the thermistor 11 is detected. When the temperature of the fixing device is lower than the target temperature, the fixing heater is turned on. In order to reduce the frequency, the temperature of the fixing member is kept constant by hysteresis temperature control that turns on the fixing heater when the temperature is lower than the target value temperature range, and turns it off when the temperature is higher than the target value temperature range in order to reduce the on / off frequency of the fixing heater. .

FIG. 5 is a diagram for explaining the effective power in the fixing device having the two heater configuration of FIG.
Referring to FIG. 5, here, heater lighting conditions and effective power supplied to the fixing device in the time series of the fixing device in the power distribution configuration are shown.

  Specifically, when the power of the image forming apparatus is turned on, first, each system is started and warm-up for heating the fixing device to a predetermined temperature is performed. Here, a total of 1300 watts of the 800 W center heater 10A and the 500 W end heater 10B is fully lit, and the fixing roller is heated for several seconds to several tens of seconds.

  Thus, during warm-up, short warm-up is possible by controlling full lighting.

  Next, when the warm-up is completed and a standby state is reached, a period of normal temperature control is entered. Also, when the image forming apparatus enters the print operation mode, the heater is turned on by normal temperature control.

  In the normal temperature control section with this configuration, the AC zero cross of the current is detected, and the AC half-wave cycle is thinned out to reduce the effective power.

  The 800 W center heater 10A is thinned out by half a cycle, and the heater is turned on with an on / off duty of two-thirds cycle, and the effective power is set to 533W.

Similarly, the 500 W end heater 10B has an effective power of 333W.
By implementing AC half-wave cycle control in this way, the effective value of power is reduced, so that the temperature ripple of the fixing member can be reduced or the total power and current combined with the operating power of the image forming apparatus can be suppressed. It becomes. In addition, by thinning out by cycle control, the initial inrush current value when entering the heater lighting section is also suppressed, and as a result, the flicker value is suppressed.

FIG. 6 is a diagram illustrating a fixing device having a three heater configuration.
Referring to FIG. 6, as an example, warm-up heater 10C is a 434W heater, center heater 10D is a 533W heater, and end heater 10E has an end arrangement for heating the end of a large-size sheet. It is assumed that the light has a 333 W heater configuration.

  It is assumed that at least one thermistor 11 for measuring the temperature of the heated fixing member and maintaining a predetermined temperature is installed in the fixing device.

  In this system, the total power of the two heaters, the warm-up heater and the temperature control heater, achieves a short warm-up as the same power as that in the configuration for performing the AC half-wave cycle control, and two heaters are used during normal temperature control. Is controlled so that the effective power at that time is equivalent to the effective power when the AC half-wave cycle control is performed, and the power of the two heaters is distributed to restrict current regulation, temperature ripple, and internal environment. Is to eliminate.

FIG. 7 is a diagram for explaining the effective power in the fixing device having the three heater configuration of FIG.
Referring to FIG. 7, here, the heater lighting state in time series of the fixing device in the power distribution configuration and the effective power supplied to the fixing device are shown.

  Specifically, when the power of the image forming apparatus is turned on, first, each system is started and warm-up for heating the fixing device to a predetermined temperature is performed. Here, a total of 1300 W of the 434 W warm-up heater 10 C, the 533 W center heater 10 D, and the 333 W end heater 10 E is fully lit, and the fixing roller is heated for several seconds to several tens of seconds.

  Thus, during warm-up, short warm-up is possible by performing full lighting control.

  Next, when the warm-up is completed and a standby state is reached, a period of normal temperature control is entered. Also, when the image forming apparatus enters the print operation mode, the heater is turned on by normal temperature control.

  In the normal temperature control section with this configuration, the warm-up heater 10C is not lit, and the 533W center heater 10D and the 333W end heater 10E are fully lit.

  In this normal temperature control section, the total effective value of power is 866 W, which is the same effective power as in the case of the two-heater configuration described in FIG. 5, and the operation of the image forming apparatus while reducing the temperature ripple of the fixing member. It is also possible to suppress the total power and current combined with the power.

  In addition, since it is only turned on at full power, it suppresses the problem that lighting equipment such as fluorescent lamps that are connected to the same power supply system flickers due to power supply fluctuations due to current fluctuation caused by turning on and off the short cycle of an AC half-wave. There is an advantage that is possible.

  As described above, even in the system configuration of the same image forming apparatus, a system configured with two heaters as shown in FIGS. 4 and 5 with an emphasis on cost and flicker suppression, and a flicker problem with an emphasis on the flicker problem, FIGS. And a system comprising three heaters as shown in FIG.

  Next, the contents for controlling the heater lighting corresponding to the difference in the power distribution of the fixing heater of the fixing device according to the embodiment of the present invention will be described.

  FIG. 8 is a diagram illustrating effective power in the fixing device having the two-heater configuration of FIG. 4 according to the embodiment of the present invention.

  FIG. 9 is a diagram illustrating effective power in the fixing device having the three-heater configuration of FIG. 6 according to the embodiment of the present invention.

  Referring to FIGS. 8 and 9, the fixing device according to the embodiment of the present invention is different from the examples of FIGS. 5 and 7 in that a heater power distribution configuration detection section is further provided.

  Specifically, in FIG. 8, the center heater 10A and the end heater 10B are fully lit and the effective power is 1300 W in the two heater configuration.

  In FIG. 9, in the three heater configuration, the warm-up heater 10C, the center heater 10D, and the end heater 10E are fully lit to 1300W.

  FIG. 10 is a diagram illustrating the transition of the temperature of the heating member of the fixing device according to the embodiment of the present invention.

  Referring to FIG. 10, in the warm-up section, in the case of the two heater configuration, the center heater 10A and the end heater 10B are fully lit and 1300 W is applied. In the case of the three heater configuration, the center heater 10D and the end heater 10E are fully lit and 866 W is applied.

  After reaching the target warm-up completion temperature of 150 ° C. in 10 seconds each, a section for detecting the heater power distribution configuration is entered.

  In the case of the two heater configuration, the center heater 10A and the end heater 10B are fully lit for a predetermined time.

  In the case of the three heater configuration, the center heater 10D and the end heater 10E are fully lit for a predetermined time. In this example, the predetermined time is set to 3 seconds in which a sufficient difference in temperature rise occurs when the center heater and the end heater are fully lit.

  In the case of the two heater configuration, an effective power of 1300 W is applied, and the temperature of the heating member rises to 190 ° C. during a predetermined time (3 s).

  On the other hand, in the case of the three heater configuration, an effective power of 866 W is applied, and the temperature of the heating member rises to 160 ° C. during a predetermined time (3 s).

  The CPU 23 of the image forming apparatus sets the determination temperature to 180 ° C. and determines the temperature rise of the heating member.

  When the CPU 23 of the image forming apparatus determines that the temperature of the heating member is 190 ° C., the CPU 23 recognizes that the temperature is higher than the determination temperature 180 ° C. and determines that the two-heater configuration (1300 W) is used. Based on this, normal temperature control is performed in the normal temperature control section. Specifically, AC half-wave cycle control is executed.

  On the other hand, when the CPU 23 of the image forming apparatus determines that the temperature of the heating member is 160 ° C., the CPU 23 recognizes that the temperature is lower than the determination temperature 180 ° C. and determines that the three-heater configuration (866 W) is used. Based on this, normal temperature control is performed in the normal temperature control section. Specifically, full lighting control is executed.

  The heater configuration information is stored in a memory (ROM 24 or RAM 25). By using this information when the power is turned on next time, it is possible to control heater lighting without providing a heater power distribution configuration detection section.

  FIG. 11 is a flowchart illustrating a flow of processing for controlling heater lighting corresponding to a difference in power distribution of the fixing heater of the fixing device according to the embodiment of the present invention.

Referring to FIG. 11, first, it is determined whether or not the power is turned on (step S2).
The CPU 23 instructs the fixing heater 10 to start warm-up (step S4). Specifically, 1300 W is applied until the heating member reaches 150 ° C. by instructing the fixing heater to fully light.

  Next, the CPU 23 determines whether heater configuration information is stored in the memory (step S6). Specifically, the CPU 23 determines whether the ROM 24 or the RAM 25 stores information for identifying the two-heater configuration or the three-heater configuration as the configuration of the fixing heater of the fixing device.

  If the CPU 23 determines in step S6 that the heater configuration information is stored in the memory (YES in step S6), the process proceeds to step S14. On the other hand, when it is determined that the heater configuration information is not stored in the memory (NO in step S6), the process proceeds to step S8.

  If the CPU 23 determines that the heater configuration information is stored in the memory, the CPU 23 turns on the fixing heater fully (step S14). Specifically, the fixing heater is fully lit for a predetermined time (3 s) in the heater power distribution configuration detection section.

  Next, the CPU 23 determines whether or not the temperature is equal to or higher than a predetermined temperature (step S16). Specifically, it is determined whether the temperature of the heating member is 180 ° C. or higher.

  In step S16, if the CPU 23 determines that the temperature is equal to or higher than the predetermined temperature (YES in step S16), the CPU 23 determines that the power is large (two heater configuration) (step S18). And based on this, normal temperature control is implemented in a normal temperature control area (step S20). Specifically, AC half-wave cycle control is executed.

  Next, the CPU 23 determines whether or not the heater configuration information can be stored in the ROM 24 (step S22).

  In step S22, if the CPU 23 determines that the heater configuration information can be stored in the ROM 24 (YES in step S22), the CPU 24 stores the heater configuration information in the ROM 24. Then, the process ends (END). As the ROM 24, for example, a backup ROM or the like can be used.

  On the other hand, if the CPU 23 determines in step S22 that the heater configuration information cannot be stored in the ROM 24 due to restrictions such as access (NO in step S22), the CPU 25 stores the heater configuration information in the RAM 25. Then, the process ends (END). Note that the RAM 25 is preferably a nonvolatile memory.

  If the CPU 23 determines in step S16 that the temperature is not equal to or higher than the predetermined temperature (NO in step S16), the CPU 23 determines that the power is small (three heater configuration) (step S26). And based on this, normal temperature control is implemented in a normal temperature control area (step S28). Specifically, full lighting control is executed.

  Then, the process proceeds to step S22, and the same processing as described above is executed. Specifically, the heater configuration information is stored in the memory.

  By storing the heater configuration information in the memory, the information can be used when the power is turned on again.

  In step S6, if the CPU 23 determines that there is heater configuration information in the memory (NO in step S6), the CPU 23 next determines whether the heater configuration information is information for identifying the two heater configuration. Judgment is made (step S8).

  In step S8, when the CPU 23 determines that the heater configuration information is information for identifying the two heater configuration (YES in step S8), the CPU 23 performs the normal temperature control in the normal temperature control section. (Step S12). Specifically, AC half-wave cycle control is executed. Then, the process ends (END).

  On the other hand, when the CPU 23 determines in step S8 that the heater configuration information is not information for identifying the two heater configuration (NO in step S8), the CPU 23 performs normal temperature control in the normal temperature control section. (Step S10). Specifically, full lighting control is executed. Then, the process ends (END).

  By using the heater configuration information at the next power-on by this processing, it is possible to control the heater lighting without providing a heater power distribution configuration detection section.

  Therefore, even when the configuration of the fixing heater cannot be grasped by the method according to the embodiment of the present invention, a difference in the rising temperature of the fixing member is detected by energization, and lighting control of the fixing heater is controlled based on the detection result. Therefore, the heater lighting control suitable for the power distribution configuration of the fixing heater can be automatically and reliably performed.

  In addition, after the warm-up is completed with all the heaters fully lit, the heater for temperature control is fully lit to detect the rising temperature, and by executing the heater lighting control corresponding to the difference in the power distribution of the fixing heater, A difference in the power distribution configuration of the fixing heater can be detected without impairing the warm-up time.

  In addition, when it is determined that the temperature rise is higher than the predetermined value, it is determined that the heater power is high, and switching to AC half-wave cycle control satisfies the flicker regulation and reduces the temperature ripple. It is possible to perform heater lighting suitable for the configuration.

  In addition, when it is determined that the temperature rise is lower than the predetermined value, it is determined that the heater power is low, and by continuing to perform the full lighting control, the required effective power is satisfied and the heater configuration is inexpensive. The heater can be turned on.

  In addition, heater configuration information that discriminates the difference in power distribution of the fixing heater is stored in a memory such as a RAM or a backup ROM, so that the heater lighting suitable for the power distribution configuration of the fixing heater can be achieved even in an inexpensive system without a backup ROM. Control can be executed, and when a backup ROM is mounted, control for detecting the power distribution configuration of the fixing heater can be omitted, so that time loss due to control can be reduced.

  In this example, the method of determining the heater configuration based on whether the temperature is higher or lower than the predetermined temperature has been described. However, the present invention is not limited to this. For example, the heater configuration is determined according to a temperature rise gradient or a rise temperature difference. You may do it.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Separation claw, 2 discharge roller, 3 pressure roller, 4 cleaning part, 5 static elimination part, 6 charging part, 7 exposure part, 8 developing part, 9 fixing roller, 10 fixing heater, 10A, 10D center heater, 10B, 10E end heater, 10C warm-up heater, 11 thermistor, 12 transport roller, 13 photoconductor, 14 transfer unit, 15 A / D conversion unit, 17 output port, 18 drive control unit, 19 laser control unit, 22 timer, 24 ROM, 25 RAM, 26 communication unit, 27 reading unit, 28 operation display unit, 100 image forming apparatus.

Claims (6)

A fixing device for fixing toner transferred to a recording paper,
A fixing member;
A heater unit composed of a plurality of heaters each having different power distribution for heating the fixing member to a predetermined fixing temperature;
A temperature detector for detecting the temperature of the fixing member;
A control unit that performs lighting control of the heater unit,
The control unit detects a temperature increase value of the fixing member by the temperature detection unit, and performs lighting control corresponding to a difference in power distribution of the heater unit based on a detection result.   The control unit performs full lighting control of all the heaters after the warm-up is completed, detects the temperature rise value of the fixing member by the temperature detection unit, and responds to the difference in power distribution of the heater unit based on the detection result The fixing device according to claim 1, wherein the lighting control is performed. The control unit stores the detection result in a memory,
After the warm-up is completed, the control unit performs full lighting control of all the heaters, and before the temperature detection unit detects the temperature rise value of the fixing member, is the detection result stored in the memory? Determine whether or not
The fixing device according to claim 2, wherein when the detection result is stored in the memory, lighting control corresponding to a difference in power distribution of the heater unit is executed based on the detection result.   The control unit performs AC half-wave cycle control on the heater unit when the temperature detection unit determines that the temperature rise value of the fixing member is equal to or greater than a predetermined value. The fixing device according to any one of the above.   The said control part performs full lighting control with respect to the said heater part, when the temperature detection part judges that the temperature rise value of the said fixing member is less than predetermined value, The any one of Claims 1-3 A fixing device according to claim 1. An image forming unit that forms a toner image and transfers the toner image to the recording paper;
An image forming apparatus comprising the fixing device according to claim 1.

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