JP2019035890A - Image forming apparatus and fixing control method - Google Patents

Abstract

To provide an image forming apparatus and a fixing control method that can reduce the occurrence of a fixing failure due to a reduction in voltage of a commercial power supply.SOLUTION: An image forming unit 13 forms a toner image on a sheet. A fixing unit 14 heats the toner image to fix the toner image to the sheet. A detection processing unit 161 detects a reduction in voltage of a commercial power supply. A recording processing unit 162 records a result of detection performed by the detection processing unit 161 in a storage unit 15 as voltage reduction history information D1. A fixing control unit 163 corrects a target temperature of the fixing unit 14 on the basis of the voltage reduction history information D1.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image forming apparatus and a fixing control method.

  An image forming apparatus capable of detecting an abnormality in the voltage of the commercial power supply based on the amount of change in the voltage of the commercial power supply during warm-up, and preventing a fixing failure by changing the fixing condition when the abnormality is detected Is known (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2015-210355

  However, in the image forming apparatus, when an abnormality occurs in the voltage of the commercial power supply after warm-up, fixing failure cannot be prevented.

  An object of the present invention is to provide an image forming apparatus and a fixing control method capable of suppressing the occurrence of fixing failure due to a decrease in the voltage of a commercial power source.

  An image forming apparatus according to one aspect of the present invention includes an image forming unit, a fixing unit, a detection processing unit, a recording processing unit, and a fixing control unit. The image forming unit forms a toner image on a sheet. The fixing unit heats the toner image to fix the toner image on the sheet. The detection processing unit detects a decrease in the voltage of the commercial power source. The recording processing unit records the detection result of the detection processing unit in a nonvolatile memory as voltage drop history information. The fixing control unit corrects a target temperature of the fixing unit based on the voltage drop history information.

  A fixing control method according to one aspect of the present invention is a fixing control method in an image forming apparatus including an image forming unit and a fixing unit. The image forming unit forms a toner image on a sheet. The fixing unit heats the toner image to fix the toner image on the sheet. The fixing control method includes a detection step, a recording step, and a correction step. In the detection step, a drop in the voltage of the commercial power source is detected. In the recording step, the detection result of the detection step is recorded in the nonvolatile memory as voltage drop history information. In the correction step, the target temperature of the fixing unit is corrected based on the voltage drop history information.

  According to the present invention, there is provided an image forming apparatus and a fixing control method capable of suppressing the occurrence of fixing failure due to a decrease in the voltage of a commercial power supply.

FIG. 1 is a block diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing a system configuration relating to fixing control in the image forming apparatus according to the embodiment of the present invention. FIG. 3 is a diagram showing an example of the voltage drop history information used in the image forming apparatus according to the embodiment of the present invention. FIG. 4 is a diagram illustrating an example of a procedure of recording processing executed by the image forming apparatus according to the embodiment of the present invention. FIG. 5 is a diagram illustrating an example of a procedure of correction processing executed by the image forming apparatus according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.

[Configuration of Image Forming Apparatus]
As shown in FIG. 1, an image forming apparatus 1 according to an embodiment of the present invention includes an operation display unit 10, an ADF (Auto Document Feeder) 11, an image reading unit 12, an image forming unit 13, a fixing unit 14, and a storage unit. 15 and a control unit 16. Specifically, the image forming apparatus 1 is a multifunction machine having a printer function, a scanner function, a copy function, a facsimile function, and the like. The present invention is not limited to a multi-function machine, and can be applied to any image forming apparatus such as a copier, a printer, and a facsimile machine.

  The operation display unit 10 includes a display unit such as a liquid crystal display that displays information, and an operation unit such as a touch panel and operation buttons that accept user operations.

  The ADF 11 is an automatic document conveyance device that includes a document setting unit, a conveyance roller, a document pressing unit, and a paper discharge unit, and conveys a document to be read by the image reading unit 12.

  The image reading unit 12 includes a document table, a light source, a mirror, an optical lens, and a CCD (Charge Coupled Device), and can read an image of the document and output it as image data.

  The image forming unit 13 forms a toner image on a sheet by electrophotography. The image forming unit 13 includes a photosensitive drum, a charger, an exposure device, a developing device, and a transfer device.

  The fixing unit 14 heats the toner image formed on the sheet to fix the toner image on the sheet. The fixing unit 14 includes a heating roller (not shown) and a pressure roller (not shown) arranged to face the heating roller. The sheet on which the toner image is formed by the image forming unit 13 is conveyed while being sandwiched between the heating roller and the pressure roller. As a result, the toner image formed on the sheet is heated and pressurized and fixed on the sheet.

  The storage unit 15 is a non-volatile storage unit such as a hard disk or an EEPROM (registered trademark). The storage unit 15 stores various control programs executed by the control unit 16, various data, and the like.

  The control unit 16 includes control devices such as a CPU, a ROM, and a RAM. The CPU is a processor that executes various arithmetic processes. The ROM is a non-volatile storage unit in which information such as a control program for causing the CPU to execute various processes is stored in advance. The RAM is a volatile or nonvolatile storage unit used as a temporary storage memory (working area) for various processes executed by the CPU. The control unit 16 may include a plurality of processors mounted on different boards.

  Next, fixing control in the image forming apparatus 1 will be described with reference to FIG.

  As shown in FIG. 2, the fixing unit 14 includes a heater 141 and a temperature sensor 142. The heater 141 heats the heating roller in response to a control signal from the control unit 16. The temperature sensor 142 is a sensor for detecting the temperature of the heating roller. The control unit 16 feedback-controls the heater 141 according to the temperature detected by the temperature sensor 142 so that the temperature of the heating roller becomes the target temperature. The heater 141 is supplied with commercial power (for example, 100V AC power, 200V AC power, etc.) through the power plug 21.

  By the way, as a related technique related to the present embodiment, an abnormality in the voltage of the commercial power supply is detected based on the amount of change in the voltage of the commercial power supply during warm-up, and the fixing condition is changed when an abnormality is detected. An image forming apparatus capable of preventing a fixing failure is known. However, in the related art, when an abnormality occurs in the voltage of the commercial power supply after warm-up, fixing failure cannot be prevented. On the other hand, in the image forming apparatus 1 according to this embodiment, as described below, it is possible to suppress the occurrence of fixing failure due to a decrease in the voltage of the commercial power source.

  Specifically, the image forming apparatus 1 includes a voltage detection circuit 22 that detects the voltage of the commercial power supplied through the power plug 21. The voltage detection circuit 22 includes, for example, a rectifier circuit that converts an AC voltage into a DC voltage and an AD converter.

  The control unit 16 includes a detection processing unit 161, a recording processing unit 162, and a fixing control unit 163. The control unit 16 functions as each of these processing units by executing various processes according to the control program. Moreover, the control part 16 may be provided with the electronic circuit which implement | achieves a part or some processing function of each of these process parts.

  The detection processing unit 161 detects a decrease in the voltage of the commercial power supply. Specifically, the detection processing unit 161 monitors the voltage of the commercial power source detected by the voltage detection circuit 22 and detects a decrease in the voltage of the commercial power source. For example, the detection processing unit 161 determines that the voltage of the commercial power supply has decreased when the voltage of the commercial power supply has decreased by a predetermined value or more from a normal voltage value (for example, 100 V).

  The recording processing unit 162 records the detection result of the detection processing unit 161 in the storage unit 15 (an example of the nonvolatile memory of the present invention) as the voltage drop history information D1 (see FIG. 3). In addition, only the detection result of the detection process part 161 in the past fixed period (For example, the past one week, the past one month, the past one year, etc.) may be recorded on the voltage fall log | history information D1. In this case, the old detection result is deleted from the voltage drop history information D1 as needed.

  For example, the recording processing unit 162 detects a voltage value (for example, “80 V”, “95 V”, etc.) or a voltage decrease amount (for example, “−10 V”, “−5 V”) when a decrease in the voltage of the commercial power supply is detected. Voltage drop history information D1 including voltage value information (for example, information on “voltage” in FIG. 3) may be recorded. Further, the recording processing unit 162 may record the voltage decrease history information D1 including the number of times information indicating the number of times the voltage decrease of the commercial power supply is detected (for example, “2 times”, “5 times”, etc.). . In the voltage drop history information D1 shown in FIG. 3, the number of records included in the voltage drop history information D1 corresponds to the number information. In addition, the recording processing unit 162 displays time information (for example, “time” in FIG. 3) indicating the length of time (for example, “5 seconds”, “10 seconds”, etc.) when the voltage drop of the commercial power supply is detected. Voltage drop history information D1 including information) may be recorded. The recording processing unit 162 also includes a month (for example, “January”, “March”, etc.), a day (for example, “10th day”, “15th day”, etc.) in which a drop in the voltage of the commercial power source is detected. Day of the week (eg, “Monday”, “Wednesday”, etc.), time zone (eg, “7 o'clock to 8 o'clock”, “15 o'clock to 16 o'clock”), and time (eg, “7: 3”, “ Voltage drop history information D1 including occurrence timing information (for example, “date” and “time zone” information in FIG. 3) indicating at least one of “7:15” or the like) may be recorded.

  The fixing control unit 163 corrects the target temperature of the fixing unit 14 based on the voltage drop history information D1. That is, the fixing control unit 163 prepares for the voltage drop of the commercial power supply when it is predicted that the voltage of the commercial power supply is likely to drop from the voltage drop history information D1 recorded in the past. The target temperature of the fixing unit 14 is set higher than usual. As a result, since a larger amount of heat than usual is stored in the fixing unit 14, even if the voltage of the commercial power supply is reduced, the occurrence of fixing failure due to the temperature drop of the fixing unit 14 is suppressed.

  In addition, it is expected that the voltage value when the voltage of the commercial power supply is lowered is lowered as the voltage value when the voltage drop of the commercial power supply is detected in the past is lowered. Therefore, the fixing control unit 163 may correct the target temperature of the fixing unit 14 based on the voltage value information included in the voltage drop history information D1. Specifically, the fixing control unit 163 may increase the correction amount of the target temperature of the fixing unit 14 as the voltage value indicated by the voltage value information is lower. For example, when the voltage value indicated by the voltage value information is 97V, the fixing control unit 163 does not correct the target temperature of the fixing unit 14, and when the voltage value indicated by the voltage value information is 93V. The target temperature of the fixing unit 14 may be increased by 5 ° C.

  In addition, it is expected that the frequency (possibility) that the voltage of the commercial power supply will decrease from now on increases as the number of times the voltage drop of the commercial power supply is detected in the past (for example, the number of times in the past fixed period) increases. Therefore, the fixing control unit 163 may correct the target temperature of the fixing unit 14 based on the number-of-times information included in the voltage drop history information D1. Specifically, the fixing control unit 163 may increase the correction amount of the target temperature of the fixing unit 14 as the number of times indicated by the number of times information increases.

  In addition, it is expected that the longer the time when the voltage drop of the commercial power supply is detected in the past, the longer the voltage drop time when the voltage of the commercial power supply is lowered. Therefore, the fixing control unit 163 may correct the target temperature of the fixing unit 14 based on the time information included in the voltage drop history information D1. Specifically, the fixing control unit 163 may increase the correction amount of the target temperature of the fixing unit 14 as the time indicated by the time information is longer.

  Further, it is expected that the commercial power supply voltage is likely to drop in the same time zone in which the voltage drop of the commercial power supply is detected in the past. For example, in a factory where a large number of devices are activated in the time zone from 7 o'clock to 8 o'clock, there is a high possibility that the voltage of the commercial power supply will decrease in the time zone from 7 o'clock to 8 o'clock. In addition to the time zone, there is a possibility that the voltage of the commercial power source is likely to decrease at a specific month, a specific day, a specific day of the week, or a specific time. Therefore, the fixing control unit 163 may correct the target temperature of the fixing unit 14 based on the generation timing information included in the voltage drop history information D1. For example, the fixing control unit 163 sets the target temperature of the fixing unit 14 to be higher than normal in the same time zone in which the voltage drop of the commercial power supply was detected in the past, and the fixing unit 14 in other time zones. The target temperature may be a normal target temperature.

  The fixing control unit 163 may correct the target temperature of the fixing unit 14 based on any combination of the voltage value information, the number-of-times information, the time information, and the generation timing information. For example, when the voltage drop of the commercial power supply is detected twice in the time zone from 7 o'clock to 8 o'clock in the past week, the fixing control unit 163 detects the fixing unit 14 in the time zone from 7 o'clock to 8 o'clock. The target temperature may be 10 ° C. higher than usual. The fixing control unit 163 indicates a correspondence relationship between a correction condition determined by an arbitrary combination of the voltage value information, the number-of-times information, the time information, and the generation timing information, and a correction amount of the target temperature of the fixing unit 14. With reference to the correction table, the target temperature of the fixing unit 14 may be corrected with a correction amount corresponding to the correction condition. For example, the correction table is stored in advance in the ROM or the storage unit 15.

  Note that the target temperature of the fixing unit 14 may be set differently when the operation mode of the image forming apparatus 1 is on standby, during warm-up, and during printing. Specifically, the target temperature during standby is set lower than the target temperature during printing, and the target temperature during warm-up is set higher than the target temperature during printing. The fixing control unit 163 corrects at least one of the target temperature during standby, the target temperature during warm-up, and the target temperature during printing based on the voltage drop history information D1. The fixing control unit 163 may individually correct the target temperature during standby, the target temperature during warm-up, and the target temperature during printing based on the voltage drop history information D1.

  In addition, when the target temperature after correction based on the voltage drop history information D1 has not reached the predetermined upper limit temperature, the fixing control unit 163 corrects the fixing conditions other than the target temperature without changing the fixing conditions. When the later target temperature reaches the upper limit temperature, fixing conditions other than the target temperature may be corrected. Note that examples of correcting fixing conditions other than the target temperature include slowing the sheet transport speed in the fixing unit 14 and increasing the sheet transport interval in the fixing unit 14. As a result, when the corrected target temperature does not reach the upper limit temperature, fixing conditions other than the target temperature are not corrected, so that the productivity of the image forming apparatus 1 is reduced (that is, the number of printed sheets per unit time). Reduction) can be prevented. On the other hand, when the corrected target temperature has reached the upper limit temperature, fixing conditions other than the target temperature are also corrected. Therefore, even when the target temperature reaches the upper limit temperature, occurrence of fixing failure can be effectively suppressed.

  In addition to the voltage drop history information D1, the fixing control unit 163 may correct the target temperature of the fixing unit 14 based on at least one of the number of continuously printed sheets, the sheet type, and the environmental temperature. For example, the fixing control unit 163 may increase the target temperature of the fixing unit 14 as the number of continuous prints increases. For example, the fixing control unit 163 does not correct the target temperature of the fixing unit 14 when the number of continuous prints is several, and sets the target temperature of the fixing unit 14 to 5 when the number of continuous prints is several tens. The temperature may be raised. The fixing control unit 163 may increase the target temperature of the fixing unit 14 as the sheet size and thickness are increased. The fixing control unit 163 may increase the target temperature of the fixing unit 14 as the environmental temperature is lower. Note that the information on the number of continuously printed sheets and the sheet type is input by the user through the operation display unit 10, for example. The environmental temperature is detected by, for example, a temperature sensor (not shown) provided in the image forming apparatus 1.

[Recording process]
Next, an example of the procedure of the recording process executed by the control unit 16 will be described with reference to FIG. Here, steps S11, S12,... Represent the numbers of processing procedures (steps) executed by the control unit 16. Note that the recording process is started, for example, in response to the power supply of the image forming apparatus 1 being turned on, and then ended in response to the power supply of the image forming apparatus 1 being turned off.

<Step S11>
First, in step S11, the control unit 16 (detection processing unit 161) determines whether or not the voltage of the commercial power source has decreased. For example, the control unit 16 determines that the voltage of the commercial power supply has dropped when the voltage of the commercial power supply detected by the voltage detection circuit 22 has dropped from a normal value by a predetermined value or more. If it is determined that the voltage of the commercial power source has decreased (S11: Yes), the process proceeds to step S12. On the other hand, if it is determined that the voltage of the commercial power source has not decreased (S11: No), the process of step S11 is repeated until it is determined that the voltage of the commercial power source has decreased. The step S11 is an example of the detection step of the present invention.

<Step S12>
In step S12, the control unit 16 (recording processing unit 162) records the detection result in step S11 in the storage unit 15 as the voltage drop history information D1. For example, the control unit 16 records voltage drop history information D1 including at least one of the voltage value information, the frequency information, the time information, and the generation timing information in the storage unit 15. Step S12 is an example of the recording step of the present invention.

  Thus, whenever a voltage drop of the commercial power supply is detected, the voltage drop history information D1 is recorded or updated as needed. Note that the control unit 16 may delete the old detection result from the voltage drop history information D1 as needed.

[Correction process]
Next, an example of the procedure of the correction process executed by the control unit 16 will be described with reference to FIG. Here, steps S21, S22,... Represent the numbers of processing procedures (steps) executed by the control unit 16. The correction process is started in response to, for example, the power supply of the image forming apparatus 1 being turned on, and then ended in response to the power supply of the image forming apparatus 1 being turned off. That is, while the image forming apparatus 1 is powered on, the recording process and the correction process are executed in parallel.

<Step S21>
First, in step S21, the control unit 16 determines whether or not the operation state of the image forming apparatus 1 is on standby. If it is determined that the operation state of the image forming apparatus 1 is on standby (S21: Yes), the process proceeds to step S22. On the other hand, if it is determined that the operation state of the image forming apparatus 1 is not in standby (S21: No), the process proceeds to step S23.

<Step S22>
In step S <b> 22, the control unit 16 (fixing control unit 163), based on the voltage decrease history information D <b> 1 stored in the storage unit 15, waits for the target temperature (that is, the operation state of the image forming apparatus 1 is on standby). The target temperature of the fixing unit 14 is corrected as necessary. The step S22 is an example of a correction step of the present invention.

<Step S23>
In step S23, the control unit 16 determines whether or not the operation state of the image forming apparatus 1 is warming up. If it is determined that the operation state of the image forming apparatus 1 is warming up (S23: Yes), the process proceeds to step S24. On the other hand, if it is determined that the operation state of the image forming apparatus 1 is not warming up (S23: No), the process proceeds to step S25.

<Step S24>
In step S24, the control unit 16 (fixing control unit 163) determines that the target temperature during warm-up (that is, the operation state of the image forming apparatus 1 is warm) based on the voltage drop history information D1 stored in the storage unit 15. The target temperature of the fixing unit 14 when the image is being increased is corrected as necessary. For example, when the voltage value when the voltage drop of the commercial power supply is detected in the past is 80 V and the time is 10 seconds, the control unit 16 executes a print job with 30 continuous prints. The target temperature during the warm-up for starting is corrected to 160 ° C., which is 10 ° C. higher than the normal target temperature (for example, 150 ° C.). As a result, even if the voltage of the commercial power supply drops to 80 V for 10 seconds during execution of the print job, it is possible to suppress the occurrence of fixing failure without changing fixing conditions other than the target temperature. Therefore, it is possible to prevent the productivity of the image forming apparatus 1 from being lowered. The step S24 is an example of a correction step of the present invention.

<Step S25>
In step S <b> 25, the control unit 16 determines whether or not the operation state of the image forming apparatus 1 is printing. When it is determined that the operation state of the image forming apparatus 1 is printing (S25: Yes), the process proceeds to step S26. On the other hand, if it is determined that the operation state of the image forming apparatus 1 is not printing (S25: No), the process returns to step S21.

<Step S26>
In step S <b> 26, the control unit 16 (fixing control unit 163), based on the voltage drop history information D <b> 1 stored in the storage unit 15, the target temperature during printing (that is, the operation state of the image forming apparatus 1 is being printed). The target temperature of the fixing unit 14 is corrected as necessary. Then, the process returns to step S21. The step S26 is an example of a correction step of the present invention.

  In this way, the target temperature during standby, the target temperature during warm-up, and the target temperature during printing are corrected so as to be higher than usual as necessary, based on the voltage drop history information D1 recorded in the past. The

  In another embodiment, for example, when a predetermined correction amount determination timing such as once per hour or once a day has arrived, standby or warm-up is performed based on the voltage drop history information D1. The correction amount for each target temperature during printing is determined in advance and stored in the storage unit 15, and the target amount is stored using the correction amount stored in the storage unit 15 until the next correction timing arrives. The temperature may be corrected.

  In yet another embodiment, the control unit 16 may first determine whether or not the target temperature of the fixing unit 14 needs to be corrected based on the voltage drop history information D1. Then, only when it is determined that the target temperature of the fixing unit 14 needs to be corrected, the control unit 16 may execute the processes of steps S21 to S26 shown in FIG. For example, when it is determined that the target temperature of the fixing unit 14 needs to be corrected only in the time zone from 7:00 to 8:00 and the time zone from 15:00 to 16:00 based on the voltage drop history information D1, 16 may execute the processing of steps S21 to S26 shown in FIG. 5 only in these time zones. Thereby, the processing burden of the control part 16 in another time slot | zone can be reduced.

  As described above, according to the image forming apparatus 1 according to the present embodiment, based on the voltage drop history information D1 recorded in the past, the target temperature of the fixing unit 14 becomes higher than usual as necessary. It is corrected. Therefore, even if the voltage of the commercial power supply is reduced, the occurrence of fixing failure due to the temperature drop of the fixing unit 14 is suppressed.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 13 Image forming part 14 Fixing part 141 Heater 142 Temperature sensor 15 Storage part 16 Control part 161 Detection processing part 162 Recording processing part 163 Fixing control part 21 Power plug 22 Voltage detection circuit

Claims (10)

An image forming unit for forming a toner image on a sheet;
A fixing unit that heats the toner image and fixes the toner image on the sheet;
A detection processing unit that detects a drop in the voltage of the commercial power supply;
A recording processing unit for recording the detection result of the detection processing unit in a nonvolatile memory as voltage drop history information;
A fixing control unit for correcting a target temperature of the fixing unit based on the voltage drop history information;
An image forming apparatus comprising: The recording processing unit records voltage drop history information including voltage value information indicating a voltage value or a voltage drop amount when a voltage drop of a commercial power supply is detected,
The fixing control unit corrects the target temperature based on the voltage value information included in the voltage drop history information;
The image forming apparatus according to claim 1. The recording processing unit records voltage decrease history information including number information indicating the number of times a decrease in the voltage of the commercial power source is detected,
The fixing control unit corrects the target temperature based on the number-of-times information included in the voltage drop history information;
The image forming apparatus according to claim 1. The recording processing unit records voltage drop history information including time information indicating a length of time when a voltage drop of a commercial power supply is detected,
The fixing control unit corrects the target temperature based on the time information included in the voltage drop history information;
The image forming apparatus according to claim 1. The recording processing unit records voltage decrease history information including generation timing information indicating at least one of a month, a day, a day of the week, a time zone, and a time when a decrease in the voltage of the commercial power source is detected,
The fixing control unit corrects the target temperature based on the generation timing information included in the voltage drop history information;
The image forming apparatus according to claim 1. The fixing control unit corrects at least one of a target temperature during standby, a target temperature during warm-up, and a target temperature during printing based on the voltage drop history information;
The image forming apparatus according to claim 1. The fixing control unit individually corrects the target temperature during standby, the target temperature during warm-up, and the target temperature during printing based on the voltage drop history information.
The image forming apparatus according to claim 6. When the corrected target temperature does not reach a predetermined upper limit temperature, the fixing control unit does not change fixing conditions other than the target temperature, and the corrected target temperature reaches the upper limit temperature. Correct the fixing conditions other than the target temperature,
The image forming apparatus according to claim 1. The fixing control unit corrects the target temperature based on at least one of a continuous print number, a sheet type, and an environmental temperature in addition to the voltage drop history information;
The image forming apparatus according to claim 1. A fixing control method in an image forming apparatus, comprising: an image forming unit that forms a toner image on a sheet; and a fixing unit that heats the toner image and fixes the toner image on the sheet.
A detection step for detecting a drop in the voltage of the commercial power supply;
A recording step of recording the detection result of the detection step in a nonvolatile memory as voltage drop history information;
A correction step of correcting a target temperature of the fixing unit based on the voltage drop history information;
A fixing control method.

Images