Image forming apparatus

Abstract

To provide an image forming apparatus that notifies a user of an abnormality in the frequency of a power supply more appropriately than before.SOLUTION: An image forming apparatus comprises: an image forming unit that performs image formation with a fixing unit that heats and fixes toner to printing paper; a power supply frequency detection unit that detects an abnormality in the frequency of an AC power supply that supplies power to a heater lamp of a heating circuit of the fixing unit; an operation panel that displays various types of information to a user and receives an instruction from the user; and a control unit that controls the image forming unit, the power supply frequency detection unit, and the operation panel. When the power supply frequency detection unit detects an abnormality in the frequency of the AC power supply, the control unit causes the operation panel to display a predetermined warning.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] This disclosure relates to an image forming apparatus, and more particularly to an image forming apparatus including a fixing unit that heats and fixes toner transferred by an electrophotographic method onto printing paper.

Background Art

[0002] Conventionally, an image forming apparatus including a fixing unit that heats toner transferred by an electrophotographic method to a predetermined temperature and fixes it onto printing paper is known.

[0003] Generally, a zero-cross signal output by detecting the zero-cross point of the AC voltage of the power supply is used for phase control of the heater lamp of the fixing unit used in such an image forming apparatus.

[0004] This zero-cross signal needs to have a stable period in order to perform temperature control of the fixing unit as intended. However, if the image forming apparatus is connected to the power supply with a coiled cord, operated simultaneously with other devices on one circuit (breaker), or operated simultaneously with a device that consumes a large amount of power such as a microwave oven nearby, the zero-cross signal may be disturbed, and the temperature of the fixing unit may not be controlled normally.

[0005] In response to such problems, conventionally, when there is an abnormality in the frequency detection of the power supply, a fixing control device capable of operating the device without stopping even during a frequency detection abnormality by performing switching control of a fixing heater that does not depend on the frequency has been disclosed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, when the conventional fixing control device detects an abnormality in the power supply frequency, it continues the operation of the image forming apparatus by control to compensate for the abnormal state, but this is only a temporary avoidance, and there is a problem that it is difficult to ensure the quality of the printing result when the continuous operation is performed in such an installation environment. In addition, when the control to compensate for the abnormal state does not work well, the image forming apparatus stops with an error display such as a low-temperature trouble in the fixing unit, but there is also a problem that it is difficult to identify the cause of the error.

[0008] As a result, the temperature change of the heater in the fixing unit cannot be controlled, and in the worst case, there is a risk of serious accidents such as ignition of the fixing unit.

[0009] This disclosure has been made in consideration of the above circumstances, and provides an image forming apparatus that more appropriately notifies a user of an abnormality in the power supply frequency than in the prior art.

Means for Solving the Problems

[0010] The image forming apparatus according to this disclosure includes an image forming unit that forms an image by a fixing unit that heats and fixes toner on printing paper, a power supply frequency detection unit that detects an abnormality in the frequency of an AC power supply that supplies power to a heater lamp of a heating circuit of the fixing unit, an operation panel that displays various information to a user and receives an instruction from the user, and a control unit that controls the image forming unit, the power supply frequency detection unit, and the operation panel. When the power supply frequency detection unit detects an abnormality in the frequency of the AC power supply, the control unit causes the operation panel to display a predetermined warning.

Effects of the Invention

[0011] According to this disclosure, an image forming apparatus that more appropriately notifies a user of an abnormality in the power supply frequency than in the prior art can be realized.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Embodiments for Carrying Out the Invention

[0013] In this disclosure, an "image forming apparatus" is an apparatus that forms and outputs an image, such as a copying machine or a multifunction device having a copying function (copying function) like a printer that uses an electrophotographic method for image formation by toner, or an MFP (Multifunctional Peripheral) that also includes functions other than copying. The warning notification method is not limited to "displaying a predetermined warning on the operation panel". For example, it may be to output a warning message or a warning sound by voice, or to notify a warning to a management user, a service technician, etc. by mail or the like.

[0014] Furthermore, preferred embodiments of this disclosure will be described.

[0015] In the image forming apparatus according to this disclosure, when the power supply frequency detection unit stops detecting an abnormality in the frequency of the AC power supply after detecting the abnormality in the frequency of the AC power supply, the control unit may cause the operation panel to cancel the warning.

[0016] By doing so, when the power supply frequency returns to normal after detecting an abnormality in the power supply frequency, the warning can be eliminated, and an image forming apparatus that can more appropriately notify the user of the abnormality in the power supply frequency than in the prior art can be realized.

[0017] In the image forming apparatus according to this disclosure, the control unit uses the zero-cross signal of the frequency of the AC power supply for phase control of the heater lamp. When the power supply frequency detection unit detects an abnormality in the frequency of the AC power supply, it determines whether the frequency of the AC power supply is within a preset range of frequencies. When the frequency of the AC power supply is not within the range of frequencies, the warning may be displayed on the operation panel.

[0018] By doing so, since the warning is displayed only when the power supply frequency is not within the predetermined range of frequencies, an image forming apparatus that can more appropriately notify the user of the abnormality in the power supply frequency than in the prior art can be realized.

[0019] In the image forming apparatus according to this disclosure, the control unit further includes a heating temperature control unit that controls the fixing temperature of the fixing unit. The zero-cross signal of the frequency of the AC power supply is used for phase control of the heater lamp. When the power supply frequency detection unit detects an abnormality in the frequency of the AC power supply, it determines whether the fixing temperature is within a preset range of temperatures. When the fixing temperature is not within the range of temperatures, the warning may be displayed on the operation panel.

[0020] By doing so, since the warning is displayed only when the fixing temperature is not within the range of temperatures, an image forming apparatus that can more appropriately notify the user of the abnormality in the power supply frequency than in the prior art can be realized.

[0021] In the image forming apparatus according to this disclosure, when the power frequency detection unit detects an abnormality in the frequency of the AC power supply while the image forming unit is not performing image formation, the control unit causes the operation panel to display the warning. On the other hand, when the power frequency detection unit detects an abnormality in the frequency of the AC power supply while the image forming unit is performing image formation, the control unit causes the operation panel to display the warning, and the operation panel may be configured to receive an instruction on whether to interrupt the image formation.

[0022] In this way, when the image forming unit detects an abnormality in the power supply during printing, not only is a warning displayed, but an instruction on whether to interrupt the printing is also received. Thus, an image forming apparatus can be realized that more appropriately notifies the user of an abnormality in the power frequency and receives an instruction on whether to interrupt the printing.

[0023] In the image forming apparatus according to this disclosure, when the power frequency detection unit detects an abnormality in the frequency of the AC power supply while the image forming unit is performing image formation, and the image formation relates to a pre-determined high-quality image, after causing the operation panel to display the warning, the control unit may execute an automatic interruption of the image formation.

[0024] In this way, when the image forming unit detects an abnormality in the power supply during printing, if the printed image relates to a high-quality image, after displaying a warning, the printing is automatically interrupted. Thus, an image forming apparatus can be realized that more appropriately notifies the user of an abnormality in the power frequency and automatically interrupts the printing.

[0025] In the image forming apparatus according to this disclosure, the operation panel may be configured to receive an instruction to cancel the automatic interruption of the image formation.

[0026] In this way, since an instruction to cancel the automatic interruption of the printing is received, an image forming apparatus can be realized that more appropriately notifies the user of an abnormality in the power frequency and automatically interrupts the printing.

[0027] In the image forming apparatus according to this disclosure, it may further include a timing unit that measures the passage of time and a storage unit that stores information related to an abnormality in the frequency of the AC power supply, and the control unit stores, in the storage unit, information related to the abnormality in the frequency of the AC power supply including the time when the abnormality in the frequency of the AC power supply is detected and the time when the abnormality in the frequency of the AC power supply ceases to be detected, and causes the information to be displayed on the operation panel.

[0028] In this way, since information related to power supply abnormalities is stored and displayed, an image forming apparatus can be realized that more appropriately notifies the user of abnormalities in the power supply frequency than in the prior art.

[0029] Hereinafter, this disclosure will be described in more detail with reference to the drawings. It should be noted that the following description is illustrative in all respects and should not be construed as limiting this disclosure.

[0030] [Embodiment 1] Based on FIG. 1, the configuration of a digital multifunction printer 1 which is an embodiment of the image forming apparatus of this disclosure will be described. FIG. 1 is an explanatory diagram showing a schematic configuration of the digital multifunction printer 1 of this disclosure.

[0031] The digital multifunction printer 1 is a device such as a multifunction printer or an MFP (Multifunctional Peripheral) that digitally processes image data and has a copying function, a scanner function, and a facsimile function.

[0032] FIG. 2 is a cross-sectional view showing the mechanical configuration of the main body portion of the digital multifunction printer 1 shown in FIG. 1. The digital multifunction printer 1 includes a document conveyance unit 112 that conveys a document to a document reading unit 111, a document reading unit 111 that reads a document, an operation panel 103 (see FIG. 3), and an image forming unit 102 that forms an image. The digital multifunction printer 1 executes printing jobs such as scanning, printing, and copying based on instructions from a user received via the operation panel 103 or the communication unit 55 (see FIG. 3).

[0033] <Configuration of the Digital Multifunction Machine 1> Here, the internal configuration of the digital multifunction machine 1 shown in FIG. 2 will be briefly described.

[0034] In the digital multifunction machine 1, a color image using each of the colors black (K), cyan (C), magenta (M), and yellow (Y) is printed on printing paper. Alternatively, a monochrome image using a single color (for example, black) is printed on printing paper. For this reason, in order to form four types of toner images corresponding to each color, four image stations Pa, Pb, Pc, and Pd are configured, each associated with black, cyan, magenta, and yellow. Four each of the developing unit 12, the photosensitive drum 13, the drum cleaning unit 14, and the charger 15 are provided, and toner images of each color are formed on the surface of each photosensitive drum 13.

[0035] The belt cleaning device 22 removes and collects residual toner on the circulating intermediate transfer belt 21. The printing paper is drawn out from any one of the four paper feed trays 18 by the pickup roller 33 and fed to the secondary transfer unit 23 via the paper conveyance path R1. Alternatively, it is fed from the manual feed tray 19 by a pickup roller (not shown) and fed to the secondary transfer unit 23 via the paper conveyance path R1. A registration roller 34 for temporarily stopping the printing paper to align the leading edge of the printing paper is arranged on the paper conveyance path R1. Also, conveyance rollers 35 and the like for promoting the conveyance of the printing paper are arranged.

[0036] A nip area is formed between the transfer roller 23a of the secondary transfer unit 23 and the intermediate transfer belt 21. When the printing paper passes through the nip, the color toner image formed on the surface of the intermediate transfer belt 21 is transferred to the printing paper. After passing through the nip area, the printing paper is sandwiched between the heating roller 24 and the pressure roller 25 of the fixing unit 17 and heated and pressurized. By this heating and pressurization, the color toner image is fixed on the printing paper. The printing paper that has passed through the fixing unit 17 is discharged to the discharge tray 39a or 39b via the discharge roller 36a or 36b.

[0037] Next, based on FIG. 3, the electrical configuration of the digital multifunction machine 1 will be briefly described. FIG. 3 is a block diagram showing the electrical configuration of the digital multifunction machine 1 shown in FIG. 1. As shown in FIG. 3, the digital multifunction machine 1 includes a communication unit 55, a timing unit 56, a control unit 100, an image forming unit 102, an operation panel 103, a storage unit 104, a document reading unit 111, a document conveyance unit 112, and a power frequency detection unit 113.

[0038] Hereinafter, each electrical component of the digital multifunction machine 1 will be described.

[0039] The communication unit 55 transmits and receives communication data to and from external devices, and receives, for example, a print job execution request and print data from an external computer.

[0040] The timing unit 56 is a timer that acquires time through a built-in clock or a network, measures time, and counts it.

[0041] The control unit 100 integrally controls the digital multifunction machine 1 and includes at least one CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), various interface circuits, and the like.

[0042] The control unit 100 monitors and controls the detection of each sensor, motors, clutches, fixing lamps, etc., that is, monitors and controls all loads, in order to control the operation of the entire digital multifunction machine 1.

[0043] Also, the control unit 100 includes a heating temperature control unit 1001. The heating temperature control unit 1001 hourly monitors the voltage of the thermistor 110 (see FIG. 4), and when the thermistor voltage reaches the voltage corresponding to a predetermined fixing temperature, controls the photo triac 108 (see FIG. 4) to be turned on / off so that the heating temperature is maintained at the fixing temperature.

[0044] The heating temperature control unit 1001 performs phase control to output a trigger signal at a predetermined timing (phase angle) based on a zero-crossing signal output by a zero-crossing detection circuit (not shown) that detects the zero-crossing point of the AC voltage, and controls the ON / OFF of the photo-triac 108.

[0045] The image forming unit 102 prints a printed image on printing paper by an electrophotographic method. The image forming unit 102 includes electrical components related to the optical scanning unit 11, developing unit 12, photosensitive drum 13, drum cleaning unit 14, and charger 15 in FIG. 2. Further, it includes electrical components related to the intermediate transfer belt 21, fixing unit 17, paper conveyance path R1, paper feed tray 18, and discharge trays 39a and 39b. Also, it includes a heating circuit 120 that heats the fixing unit 17.

[0046] The operation panel 103 is composed of a liquid crystal display and a touch panel, and is a part that displays information on the liquid crystal display and receives commands from the user through the touch panel. The control unit 100 displays the operation and state of the digital multifunction machine 1 through the operation panel 103.

[0047] The storage unit 104 includes a RAM 104a and a ROM 104b, and is a non-volatile storage means such as a hard disc drive (HDD) or a flash memory, and stores various data and programs.

[0048] The RAM 104a is a memory accessible by the control unit 100, and provides a work memory for temporarily storing data.

[0049] The ROM 104b is a read-only memory accessible by the control unit 100, and stores data necessary for the program control of the control unit 100. In the ROM 104b, various data serving as the basis for settings such as an image forming function and a heating temperature control function are stored.

[0050] RAM 104a and ROM 104b are connected to the control unit 100 via a bus, and programs for operating the control unit 100 are stored and memory-expanded therein. These are an example of a configuration, and a system may be configured by a plurality of CPUs and circuit boards.

[0051] The power frequency detection unit 113 is a part that detects the frequency of the external AC power supply 2 connected to the power supply circuit 109. Specifically, the power frequency detection unit 113 detects the frequency by counting the passage of the zero-crossing point, which is the point when the AC voltage flowing through the power supply circuit 109 becomes 0V. The method for detecting whether the frequency is abnormal will be described later.

[0052] The control unit 100 controls, for example, the document reading unit 111 and the document conveyance unit 112 to convey the document by the document conveyance unit 112. Then, the document reading unit 111 reads the image of the document, and stores the image data indicating the image of the document in the storage unit 104. Further, the control unit 100 controls the image forming unit 102 to print the image of the document indicated by the image data in the storage unit 104 on the printing paper by the image forming unit 102.

[0053] <Electrical Configuration of the Heating Circuit 120> Next, based on FIG. 4, the electrical configuration of the heating circuit 120 will be described. FIG. 4 is a block diagram showing the electrical configuration of the heating circuit 120 of the digital multi-function machine 1 shown in FIG. 1.

[0054] As shown in FIG. 4, the heating circuit 120 includes a heater lamp 105, a first relay 107, a photo triac 108, a power supply circuit 109, and a thermistor 110.

[0055] The heating circuit 120 is a circuit for heating the fixing unit 17 of the image forming unit 102. Hereinafter, each component of the heating circuit 120 will be described.

[0056] The heater lamp 105 is a part that heats the heating roller 24 of the fixing unit 17 by being supplied with power from the power circuit 109 and generating heat.

[0057] The first relay 107 is a part that opens and closes the contact (switch) connecting the power circuit 109 and the heater lamp 105 according to a control signal from the heating temperature control unit 1001. When the heating temperature control unit 1001 determines that there is an abnormality in the frequency of the AC voltage supplied to the heater lamp 105, it automatically or based on an instruction from the user, controls the output of the first relay 107 to OFF, thereby cutting off the power supply to the heater lamp 105 and stopping the heating of the heating roller 24.

[0058] The photo triac 108 is a part that controls the power flowing through the heater lamp 105 by driving the LED incorporated in the gate of the triac (bidirectional thyristor) connecting the power circuit 109 and the heater lamp 105 with a control signal from the heating temperature control unit 1001 to put the triac into a conducting state.

[0059] The power circuit 109 is a circuit connected to an external AC power supply 2 and supplies AC power with a predetermined voltage and frequency to the heater lamp 105.

[0060] The thermistor 110 is a part that converts the temperature change of the heater lamp 105 into a change in electrical resistance value. The temperature of the heater lamp 105 is voltage-converted by the thermistor 110, the value is read by the analog port of the heating temperature control unit 1001, and is detected by comparing and calculating with a table stored in the ROM104b. Based on the calculation result, the heating temperature control unit 1001 controls the photo triac 108 to be ON / OFF and controls and monitors so that the fixing unit 17 reaches a preset fixing temperature.

[0061] <Judgment Process for Abnormality of Power Supply Frequency> Next, based on FIG. 5, the determination process for the abnormality of the power supply frequency detected by the power supply frequency detection unit 113 of the digital multi-function peripheral 1 will be described. FIG. 5 is a flowchart showing the determination process for the abnormality of the power supply frequency detected by the power supply frequency detection unit 113 of the digital multi-function peripheral 1 shown in FIG. 1.

[0062] In step S1 of FIG. 5, the control unit 100 of the digital multi-function peripheral 1 turns off all of the 50 Hz band flag, 60 Hz band flag, and frequency detection completion flag, and resets the frequency abnormality to 0 (step S1).

[0063] Next, in step S2, the control unit 100 permits the 1 ms interrupt and the zero-cross interrupt (step S2).

[0064] The processes of FIGS. 7 and 9 described later are executed in parallel with the process of FIG. 5. Permitting the 1 ms interrupt enables the process of FIG. 7 to be executed, and permitting the zero-cross interrupt enables the process of FIG. 9 to be executed. FIG. 7 (S22) is executed after the frequency detection completion flag of FIG. 9 (S38) becomes ON (the processes are in the order of FIG. 9 (S38) → FIG. 7 (S22)).

[0065] Next, in step S3, the control unit 100 determines whether the number of 1 ms interrupts is 1000 or more (1 second) (step S3).

[0066] When the number of 1 ms interrupts becomes 1000 or more (1 second) (when the determination in step S3 is Yes), in step S4, the control unit 100 calculates the current frequency CF from 1000 / ((number of 1 ms interrupts / number of zero-cross interrupts) × 2) (step S4).

[0067] FIG. 6 is an explanatory diagram showing an example of the AC input signal (after rectification) and the zero-cross signal of the power supply of the digital multi-function peripheral 1 shown in FIG. 1. FIG. 6 (A) shows the AC input signal (after rectification), and FIG. 6 (B) shows the zero-cross signal (normal).

[0068] When an AC input signal whose voltage changes in the period of a specified frequency is input, the signal after rectification becomes as shown in Fig. 6(A), and its zero-crossing signal becomes as shown in Fig. 6(B).

[0069] Fig. 7 is a flowchart showing the count process of the number of 1 ms interrupts of the digital multifunction machine 1 shown in Fig. 1.

[0070] In the example of Fig. 7, it is assumed that an interrupt is generated every 1 ms. At this time, in step S21 of Fig. 7, the control unit 100 determines whether or not the frequency detection flag is ON (step S21).

[0071] When the frequency detection flag is ON (when the determination in step S21 is Yes), in step S22, the control unit 100 increments the 1 ms interrupt count and ends the process.

[0072] On the other hand, when the frequency detection flag is not ON (when the determination in step S21 is No), the control unit 100 ends the process as it is.

[0073] For example, in step S4 of Fig. 5, when the number of zero-crossing interrupts is 100 out of 1000 times (1 second) of the 1 ms interrupt count, the current frequency CF is 1000 / ((1000 / 100) × 2) = 50 (Hz).

[0074] Next, in step S5, the control unit 100 clears the 1 ms timer interrupt count and the zero-crossing interrupt count (step S5).

[0075] Next, in step S6, the control unit 100 determines whether or not the 50 Hz band flag is ON (step S6). Note that the determination of whether or not the 50 Hz band flag is ON will be described later in the explanation of the flowchart of Fig. 9.

[0076] When the 50 Hz band flag is ON (when the determination in step S6 is Yes), in step S7, the control unit 100 determines whether the current frequency CF is equal to or greater than the 50 Hz band minimum frequency and less than the 50 Hz band maximum frequency (step S7).

[0077] FIG. 8 is a table showing an example of the range of the power supply frequency detected by the power supply frequency detection unit 113 of the digital multi-function device 1 shown in FIG. 1, the zero-cross timer count, and the number of zero-crossings in one second.

[0078] In the example of FIG. 8, the range (minimum to maximum) of the frequency range (Hz) is 30 Hz to 55 Hz for the 50 Hz band and 55 Hz to 80 Hz for the 60 Hz band. Also, in the case of other ranges (0 Hz to 30 Hz or 80 Hz to), an error occurs.

[0079] In step S7 of FIG. 5, when the current frequency CF is equal to or greater than the 50 Hz band minimum frequency and less than the 50 Hz band maximum frequency (when the determination in step S7 is Yes), in step S8, the control unit 100 sets the frequency abnormality = 0 assuming that there is no frequency abnormality (step S8).

[0080] On the other hand, when the current frequency CF is not equal to or greater than the 50 Hz band minimum frequency and less than the 50 Hz band maximum frequency (when the determination in step S7 is No), in step S9, the control unit 100 sets the frequency abnormality = the current frequency CF to record the frequency assuming that there is a frequency abnormality (step S9).

[0081] Also, in step S6, when the 50 Hz band flag is not ON (when the determination in step S6 is No), in step S10, the control unit 100 determines whether the current frequency CF is equal to or greater than the 60 Hz band minimum frequency and less than the 60 Hz band maximum frequency (step S10).

[0082] When the current frequency CF is equal to or higher than the minimum frequency of the 60 Hz band and lower than the maximum frequency of the 60 Hz band (when the determination in step S10 is Yes), in step S11, the control unit 100 sets the frequency abnormality to 0, assuming that there is no frequency abnormality (step S11).

[0083] On the other hand, when the current frequency CF is not equal to or higher than the minimum frequency of the 60 Hz band and lower than the maximum frequency of the 60 Hz band (when the determination in step S10 is No), in step S12, the control unit 100 sets the frequency abnormality to the current frequency CF, i.e., frequency abnormality = current frequency CF, in order to record the frequency assuming that there is a frequency abnormality (step S12).

[0084] Next, after the processing in steps S8, S9, S11, or S12 is completed, in step S13, the control unit 100 determines whether the frequency abnormality = 0 (step S13).

[0085] When the frequency abnormality = 0 (when the determination in step S13 is Yes), in step S14, if the control unit 100 is performing a warning notification of the power supply frequency, it cancels the warning notification (step S14). Then, the control unit 100 ends the processing.

[0086] On the other hand, when the frequency abnormality ≠ 0 (when the determination in step S13 is No), in step S15, the control unit 100 determines whether the image forming unit 102 is executing a print job (step S15).

[0087] When the image forming unit 102 is not executing a print job (when the determination in step S15 is No), in step S16, the control unit 100 performs a warning notification of the power supply frequency (step S15). Then, the control unit 100 ends the processing.

[0088] On the other hand, when the image forming unit 102 is executing a print job (when the determination in step S15 is Yes), in step S17, the control unit 100 accepts a warning notification of the power supply frequency and whether to interrupt the print job (step S17). Then, the control unit 100 ends the processing.

[0089] Figure 9 is a flowchart showing the zero-crossing interrupt processing of the digital multi-function peripheral 1 shown in FIG. 1.

[0090] When the zero-crossing interrupt starts, in step S31 of FIG. 9, the control unit 100 determines whether the frequency completion flag is OFF (step S31).

[0091] When the frequency completion flag is OFF (when the determination in step S31 is Yes), in step S32, the control unit 100 acquires the timer count value TC of the zero-crossing interrupt (step S32).

[0092] Next, in step S33, the control unit 100 determines whether the timer count value TC of the zero-crossing interrupt is equal to or greater than the 50 Hz minimum count value and less than the 50 Hz maximum count value (step S33).

[0093] In the table of FIG. 8, when it is assumed that one count is made in 0.543 μs, the range (minimum to maximum) of the zero-crossing timer count is "16757 (55 Hz) to 30720 (30 Hz)" in the 50 Hz band and "11520 (80 Hz) to 16756 (55 Hz)" in the 60 Hz band.

[0094] When the timer count value TC of the zero-crossing interrupt is equal to or greater than the 50 Hz minimum count value and less than the 50 Hz maximum count value (when the determination in step S33 is Yes), in step S34, the control unit 100 turns on the 50 Hz band flag (step S34).

[0095] On the other hand, in step S33, when the timer count value TC of the zero-crossing interrupt is not equal to or greater than the 50 Hz minimum count value and less than the 50 Hz maximum count value (when the determination in step S33 is No), in step S35, the control unit 100 determines whether the timer count value TC of the zero-crossing interrupt is equal to or greater than the 60 Hz minimum count value and less than the 60 Hz maximum count value (step S35).

[0096] When the zero-crossing interrupt timer count value TC is equal to or greater than the 60 Hz minimum count value and less than the 60 Hz maximum count value (when the determination in step S35 is Yes), in step S36, the control unit 100 turns on the 60 Hz band flag (step S36).

[0097] On the other hand, when the zero-crossing interrupt timer count value TC is not equal to or greater than the 60 Hz minimum count value and less than the 60 Hz maximum count value (when the determination in step S35 is No), in step S76, the control unit 100 performs machine trouble stop and prohibits zero-crossing interrupt (step S37).

[0098] After the processing of step S34, S36 or S37 is completed, in step S38, the control unit 100 clears the 1 ms timer interrupt count counter and the zero-crossing interrupt count counter, and turns on the frequency detection flag (step S38). Then, the control unit 100 ends the zero-crossing interrupt.

[0099] On the other hand, in the determination of step S31, when the frequency completion flag is ON (when the determination in step S31 is No), in step S39, the control unit 100 performs phase control of the heater lamp 105 (step S39).

[0100] Next, in step S40, the control unit 100 increments the zero-crossing interrupt count counter (step S40). Then, the control unit 100 ends the zero-crossing interrupt.

[0101] FIG. 10 is an explanatory diagram showing an example of a warning message when an abnormality in the power supply frequency is detected during standby of the digital multifunction machine 1 shown in FIG. 1. FIG. 10(A) shows the screen during standby, and FIG. 10(B) shows an example of a message when an abnormality in the power supply frequency is detected.

[0102] As shown in FIG. 10(A), when the operation panel 103 detects an abnormality in the power frequency while displaying the standby screen, a warning message as shown in FIG. 10(B) is pop-up displayed.

[0103] In the example of FIG. 10(B), under the message "An abnormality in the power frequency has been detected. Please check the following precautions.", the confirmation items "· Are there any devices connected to the same breaker?" "· Are you using octopus wiring or an extension cord?" "· Is there any damage to the power cord?" are displayed.

[0104] When the abnormality in the power frequency is resolved, the warning message is erased. However, the warning message may also be erased when the "OK" button in the lower right of the warning message is pressed.

[0105] FIG. 11 is an explanatory diagram showing an example of a warning message when an abnormality in the power frequency is detected during copying of the digital multifunction machine 1 shown in FIG. 1. FIG. 11(A) shows the screen during copying, and FIG. 11(B) shows an example of a message when an abnormality in the power frequency is detected.

[0106] As shown in FIG. 11(A), when the operation panel 103 detects an abnormality in the power frequency while displaying the copying screen, a warning message as shown in FIG. 11(B) is pop-up displayed.

[0107] In the example of FIG. 11(B), the confirmation item "An abnormality in the power frequency has been detected. There may be a problem with the print quality. Do you want to interrupt the job?" is displayed. The user can instruct whether to interrupt the copying by pressing the "Interrupt" button or the "Do not interrupt" button in the lower right of the warning message. When the abnormality in the power frequency is resolved, the warning message is erased.

[0108] FIG. 12 is an explanatory diagram showing an example of a warning message when copying is interrupted after detection of an abnormality in the power supply frequency detected by the power supply frequency detection unit 113 of the digital multi-function machine 1 shown in FIG. 1.

[0109] On the screen of FIG. 11(B), when the user presses the "Interrupt" button at the lower right of the warning message, a warning message as shown in FIG. 12 is popped up and displayed.

[0110] In the example of FIG. 12, below the message "An abnormality in the power supply frequency has been detected. Please check the following precautions.", confirmation items such as "· Are there any devices connected to the same breaker?", "· Are you using octopus wiring or an extension cord?", and "· Is there any damage to the power cord?" are displayed. Also, a message "※ It will automatically resume when the abnormality is resolved." is displayed below that.

[0111] When the abnormality in the power supply frequency is resolved, the warning message is erased and the interrupted copy is resumed. Note that the warning message may also be erased when the "OK" button at the lower right of the warning message is pressed. In this case, the copy may not be resumed until the abnormality in the power supply frequency is resolved.

[0112] (Modification example) As a modification example of Embodiment 1, when an abnormality in the power supply frequency is detected and when it returns to normal, the history such as those times and frequencies may be recorded. FIG. 13 is a table showing the history of abnormalities in the power supply frequency detected by the power supply frequency detection unit 113 of the digital multi-function machine 1 shown in FIG. 1.

[0113] In the example of FIG. 13, the "Date of abnormality occurrence", "Abnormal frequency", "Occurrence time", "Normal recovery time", and "Machine state" are recorded.

[0114] As the machine state, for example, states such as when the power is ON, when the door is open, during warm-up, in standby, during a job, during a jam, and during trouble can be considered.

[0115] In this way, the digital multifunction machine 1 that can more appropriately detect an abnormality in the power supply frequency than in the prior art can be realized.

[0116] [Embodiment 2] Next, with reference to FIG. 14, the determination process of the abnormality in the power supply frequency detected by the power supply frequency detection unit 113 of the digital multifunction machine 1 according to Embodiment 2 of this disclosure will be described.

[0117] Since the schematic configuration of the digital multifunction machine 1 according to Embodiment 2 is the same as that of Embodiment 1 (FIGS. 1 to 4), the description thereof will be omitted.

[0118] <Determination Process of Abnormality in Power Supply Frequency Detected by Power Supply Frequency Detection Unit 113 of Digital Multifunction Machine 1 According to Embodiment 2 of this Disclosure> FIG. 14 is a flowchart showing the determination process of the abnormality in the power supply frequency detected by the power supply frequency detection unit 113 of the digital multifunction machine 1 according to Embodiment 2 of this disclosure.

[0119] Note that since the processes in steps S41 to S54 in FIG. 14 are the same as the processes in steps S1 to S14 in FIG. 5 (Embodiment 1), the description thereof will be omitted. Here, the processes in steps S55 and S56 in FIG. 14, which are not shown in FIG. 5, will be described.

[0120] In step S53 in FIG. 14, when the frequency abnormality ≠ 0 (when the determination in step S53 is No), in step S55, the control unit 100 determines whether the current fixing temperature T is equal to or higher than the target temperature - TA °C and lower than the target temperature + TB °C (step S55).

[0121] The range of the target temperature of the fixing temperature T is, for example, 110°C to 200°C. The target temperature of the fixing temperature T is, for example, 140°C during warm-up, 130°C during job standby, 150°C during color printing (on plain paper), and 180°C during color printing (on thick paper). However, since the target temperature of the fixing temperature T and its range vary depending on the situation, it is not limited to the above.

[0122] When the current fixing temperature T is equal to or higher than the target temperature - TA °C and lower than the target temperature + TB °C (when the determination in step S55 is Yes), the control unit 100 ends the process.

[0123] On the other hand, when the current fixing temperature T is not equal to or higher than the target temperature - TA °C and lower than the target temperature + TB °C (when the determination in step S55 is No), in step S56, the control unit 100 issues a warning notification of the power frequency (step S55). Then, the control unit 100 ends the process.

[0124] (Modification example) As a modification example of Embodiment 2, when the digital multifunction machine 1 is in the sleep state or the standby state, etc., and there is no need to perform phase control of the heater lamp 105, the determination in step S55 may be omitted, and only a warning notification of the power frequency may be issued, or the process may be ended without warning notification.

[0125] In this way, it is possible to realize the digital multifunction machine 1 that determines that there is an abnormality in the power frequency only when a deviation of a predetermined temperature or more occurs between the fixing temperature and the target temperature.

[0126] 〔Embodiment 3〕 Next, with reference to FIG. 15, the determination process of the abnormality of the power frequency detected by the power frequency detection unit 113 of the digital multifunction machine 1 according to Embodiment 3 of this disclosure will be described.

[0127] Since the schematic configuration of the digital multifunction machine 1 according to Embodiment 3 is the same as that of Embodiment 1 (FIGS. 1 to 4), the description thereof will be omitted.

[0128] <Determination process of the abnormality of the power frequency detected by the power frequency detection unit 113 of the digital multifunction machine 1 according to Embodiment 3 of this disclosure> FIG. 15 is a flowchart showing the determination process of the abnormality of the power frequency detected by the power frequency detection unit 113 of the digital multifunction machine 1 according to Embodiment 3 of this disclosure.

[0129] Note that since the processes in steps S61 to S74 in FIG. 15 are the same as the processes in steps S1 to S14 in FIG. 5 (Embodiment 1), the description thereof is omitted. Here, the processes in steps S75 to S77 in FIG. 15, which are not described in FIG. 5, will be described.

[0130] In step S73 of FIG. 15, when the frequency abnormality ≠ 0 (when the determination in step S73 is No), in step S75, the control unit 100 determines whether a predetermined high-quality image such as printing on photo-glossy paper is being printed (step S75).

[0131] When a predetermined high-quality image is not being printed (when the determination in step S75 is No), in step S76, the control unit 100 issues a warning notification of the power frequency (step S76).

[0132] On the other hand, when a predetermined high-quality image is being printed (when the determination in step S75 is Yes), in step S77, after the control unit 100 issues a warning notification of the power frequency and a notification to automatically interrupt printing, it causes the image forming unit 102 to execute automatic interruption of printing (step S77). Then, the control unit 100 ends the process.

[0133] Note that the automatic interruption of printing may not be executed immediately, but may be executed after a predetermined waiting time.

[0134] (Modification example) As a modification example of Embodiment 3, the control unit 100 may display a cancel button for automatic interruption of printing on the operation panel 103 and accept the automatic interruption.

[0135] In this way, the digital multi-function peripheral 1 that determines that there is an abnormality in the power supply frequency only when a deviation of a predetermined temperature or more occurs between the fixing temperature and the target temperature can be realized.

[0136] [Embodiment 4] Next, based on FIGS. 16 and 17, the display of a warning message for an abnormality in the power supply frequency detected by the power supply frequency detection unit 113 of the digital multi-function peripheral 1 according to Embodiment 4 of this disclosure will be described. In Embodiment 4, the display of a warning message for an abnormality in the power supply frequency when the fixing unit 17 is not used will be described.

[0137] Since the schematic configuration of the digital multi-function peripheral 1 according to Embodiment 4 is the same as that of Embodiment 1 (FIGS. 1 to 4), the description thereof will be omitted.

[0138] FIG. 16 is an explanatory diagram showing an example of a warning message when an abnormality in the power supply frequency is detected in the scan mode of the digital multi-function peripheral 1 according to Embodiment 4 of this disclosure.

[0139] When the operation panel 103 detects an abnormality in the power supply frequency while displaying the screen in the scan mode, a warning message as shown in FIG. 16 is displayed. In the example of FIG. 16, only the warning message "An abnormality in the power supply frequency has been detected." is displayed at the lower left of the screen.

[0140] FIG. 17 is an explanatory diagram showing an example of a warning message when an abnormality in the power supply frequency is detected while the home screen (screen for performing function selection) of the digital multi-function peripheral 1 according to Embodiment 4 of this disclosure is being displayed. Also in the example of FIG. 17, only the warning message "An abnormality in the power supply frequency has been detected." is displayed at the lower left of the screen.

[0141] In this way, even when an abnormality in the power supply frequency is detected, when in the scan operation mode without using the fixing unit 17 or when the home screen (screen for performing function selection) is being displayed, by displaying the warning message smaller and more conservatively than in the copy mode using the fixing unit 17, it is possible to prevent the user's operation from being hindered.

[0142] Preferred embodiments of this disclosure also include combinations of any of the above-described embodiments. In addition to the above-described embodiments, there can be various modifications to this disclosure. Such modifications should not be construed as not belonging to the scope of this disclosure. This disclosure should include meanings equivalent to the claims and all modifications within the scope.

Description of Reference Numerals

[0143] 1: Digital multi-function machine, 2: AC power supply, 11: Optical scanning unit, 12: Developing unit, 13: Photoconductor drum, 14: Drum cleaning unit, 15: Charger, 17: Fixing unit, 18: Feeding tray, 19: Manual feed tray, 21: Intermediate transfer belt, 22: Belt cleaning device, 23: Secondary transfer unit, 23a: Transfer roller, 24: Heating roller, 25: Pressing roller, 33: Pickup roller, 34: Registration roller, 35: Conveyor roller, 36a, 36b: Discharge roller, 39a, 39b: Discharge tray, 55: Communication unit, 56: Timing unit, 100: Control unit, 102: Image forming unit, 103: Operation panel, 104: Storage unit, 104a: RAM, 104b: ROM, 105: Heater lamp, 107: First relay, 108: Photo triac, 109: Power circuit, 110: Thermistor, 111: Document reading unit, 112: Document conveying unit, 113: Power frequency detection unit, 120: Heating circuit, 1001: Heating temperature control unit, C: Arrow direction, CF: Current frequency, Pa, Pb, Pc, Pd: Image stations, R1: Paper conveyance path, T: Fixing temperature, TC: Timer count value

Claims

1. An image forming unit that forms an image by a fixing unit that heats and fixes toner on printing paper, A power frequency detection unit that detects an abnormality in the frequency of an AC power supply that supplies power to a heater lamp in the heating circuit of the fixing unit, An operation panel that displays various information to the user and receives the user's instructions, A control unit that controls the image forming unit, the power frequency detection unit, and the operation panel, The control unit causes the operation panel to display a predetermined warning when the power frequency detection unit detects an abnormality in the frequency of the AC power supply. An image forming apparatus characterized by this.

2. The control unit causes the operation panel to cancel the warning when the power frequency detection unit stops detecting an abnormality in the frequency of the AC power supply after detecting the abnormality in the frequency of the AC power supply. The image forming apparatus according to Claim 1.

3. The control unit uses the zero-cross signal of the frequency of the AC power supply for phase control of the heater lamp, When the power frequency detection unit detects an abnormality in the frequency of the AC power supply, it determines whether the frequency of the AC power supply is within a predetermined range of frequencies, and if the frequency of the AC power supply is not within the range of frequencies, the operation panel is caused to display the warning. The image forming apparatus according to Claim 1.

4. The control unit further includes a heating temperature control unit that controls the fixing temperature of the fixing unit, and uses the zero-cross signal of the frequency of the AC power supply for phase control of the heater lamp, When the power frequency detection unit detects an abnormality in the frequency of the AC power supply, it determines whether the fixing temperature is within a predetermined range of temperatures, and if the fixing temperature is not within the range of temperatures, the operation panel is caused to display the warning. The image forming apparatus according to Claim 1.

5. When the power frequency detection unit detects an abnormality in the frequency of the AC power supply when the image forming unit is not performing image formation, the control unit causes the operation panel to display the warning. On the other hand, when the power frequency detection unit detects an abnormality in the frequency of the AC power supply when the image forming unit is performing image formation, the operation panel displays the warning, and the operation panel receives an instruction on whether to interrupt the image formation. The image forming apparatus according to any one of Claims 1 to 4.

6. When the power frequency detection unit detects an abnormality in the frequency of the AC power supply while the image forming unit is performing the image formation, and the image formation relates to a pre-determined high-quality image, the control unit causes the operation panel to display the warning and then executes an automatic interruption of the image formation. The image forming apparatus according to claim 5. **Claim 7** The operation panel of the image forming apparatus according to claim 6 is configured to receive a cancel instruction for the automatic interruption of the image formation. **Claim 8** The image forming apparatus further includes a timing unit that measures the passage of time. The image forming apparatus further includes a storage unit that stores information related to an abnormality in the frequency of the AC power supply. When the control unit detects an abnormality in the frequency of the AC power supply, the control unit stores information related to the abnormality in the frequency of the AC power supply, including the time when the abnormality was detected and the time when the abnormality in the frequency of the AC power supply disappeared, in the storage unit and causes the information to be displayed on the operation panel. The image forming apparatus according to claim 1.

Images