JP2006010998A - Image forming apparatus and heat source control method in image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus provided with a fixing unit capable of improving temperature detection reliability and reducing power consumption even in non-contact temperature detection, and a method for controlling a heat source in the image forming apparatus. To do.
A control unit 81 that detects the temperature of a fixing belt and a pressure roller via temperature sensors 53, 63, and the like, and a temperature memory 83 that sequentially stores temperature detection data that are sequentially measured, are provided and controlled. The unit 81 sequentially acquires a predetermined plurality of continuous temperature detection data from the temperature memory 83, and sequentially averages the temperature detection data excluding the highest temperature and the lowest temperature among the plurality of continuous temperature detection data. And the actual temperature of the heat source such as the fixing belt and the pressure roller is controlled based on the temperature detection data averaged sequentially.
[Selection] Figure 3

Description

  The present invention provides an image forming apparatus capable of accurately detecting the temperature of a heat source such as a heating roller as a heating unit in a fixing unit with low power consumption and more accurately controlling the amount of heat generated by the heat source. And a method of controlling a heat source in the image forming apparatus.

In general, in an electrophotographic fixing unit, when a fixing roller or a fixing belt is used, the temperature of the fixing belt on the heating roller is controlled by, for example, each heater provided on the heating roller.
Conventionally, temperature detection was performed using a contact-type temperature detection thermistor, but recently, the heat roller and the fixing belt are scratched and the image quality is liable to deteriorate. Infrared thermistors have been used.
In the case of non-contact temperature detection, the actual temperature of the measurement object is determined by comparing the temperature of the measurement object (fixing belt, etc.) with the temperature of the detector itself. A control circuit is required to determine the temperature.

However, although the heat roller and the fixing belt are hot, the heat resistance temperature of the elements of the control circuit is low, so a configuration in which the control circuit is arranged outside the fixing unit is generally adopted, but in this case the vicinity of the control circuit is When the circuit board is the same as another circuit or when the harness passes through the vicinity of another circuit, the temperature detection is easily affected by noise.
At this time, in the non-contact temperature detection, a measurement range of about 0 ° C. to 200 ° C. is necessary in order to measure and compare the temperature of the heating roller in the fixing unit and the temperature of the non-contact temperature sensor itself. . For this reason, unlike the case of detecting a narrow temperature range as in the case of a contact type thermistor, the resistance change amount (voltage change amount) with respect to the temperature change cannot be taken large, and the sensitivity (converted output voltage per temperature difference) is extremely high. Get smaller. This means that when voltage fluctuation due to noise is superimposed on a non-contact type temperature sensor, it corresponds to a large temperature change as a detected temperature output, and accurate control cannot be performed.

As a countermeasure to this inconvenience, a method of averaging the data and using it as a detection signal can be considered, but if it is affected by noise from a high voltage system such as charging or transfer, one data affected by the noise changes greatly. Therefore, even if averaged, the influence of the noise greatly affects the average value of the result, which hinders accurate temperature detection.
In addition, when the normalization is performed as usual, the output cycle of the detection signal becomes large. However, in order to shorten the output cycle, it is necessary to remarkably shorten the data measurement cycle interval. There is a problem that it is difficult in terms of speed capability.

  In the control example related to temperature detection, first, the fixing roller heater is extra for a certain time after the pressure roller thermistor detects 167 + 0.7 ° C and the pressure roller heater is turned off. The effective amount of heat obtained by subtracting the amount of heat taken by the fixing roller from the amount of heat given to the fixing roller by the fixing roller heater in one cycle of temperature is equal to the amount of heat given to the pressing roller by the pressure roller heater. A fixing unit is known (see Patent Document 1).

As another example, secondly, the pressure roller is provided with a central heater that heats the center and an end heater that heats the end, and detects the temperature of the center and the end of the pressure roller, and the fixing roller A fixing unit is known in which, while the pair is rotating, the control means calculates the temperature of each of them to determine the median value of each temperature and controls the energization to the central heater and the end heater (for example, (See Patent Document 2).
Patent Document 1 describes that it is possible to eliminate the temperature difference between the fixing roller and the pressure roller during printing, and Patent Document 2 can shorten the rise time and perform appropriate temperature control of the heater. It is described that.

Japanese Patent Laid-Open No. 9-80970 JP-A-9-134092

Patent Document 1 does not focus on improving the reliability of temperature detection using a thermistor or the like. Therefore, the configuration is insufficient from the viewpoint of accurate temperature detection excluding the influence of noise or the like. There is a problem that the reliability in control is low.
In addition, the temperature detection signal cannot be reduced in a short cycle, and the power consumption cannot be reduced by suppressing the inrush power of the execution power given to the heater, resulting in low temperature detection reliability. In addition, there is a problem that power consumption increases.

  Also, in the past, when temperature detection is performed with a non-contact type temperature sensor, a measurement range of about 0 ° C. to 200 ° C. is required because of measuring the temperature of the fixing unit itself. As described above, in order to detect a narrow temperature range with high accuracy like a contact type thermistor, the change in temperature detection voltage (resistance) cannot be increased, resulting in voltage fluctuations due to noise. Therefore, there is a problem that the temperature detection includes a large temperature change.

Therefore, the present invention improves the above-mentioned problems of the prior art, improves the reliability of the heat source temperature detection and heat generation amount control even in the non-contact type temperature detection, and can reduce the power consumption. An object of the present invention is to provide an image forming apparatus including a unit and a method of controlling a heat source in the image forming apparatus.
Specifically, the temperature detection signal that is resistant to noise is detected in a short cycle, and when the maximum execution power given to the heat source is controlled, the inrush power of the power value is reduced, thereby reducing the power consumption. An object of the present invention is to provide an image forming apparatus including a fixing unit in which these controls are efficient and the heat source control is highly reliable, and a method for controlling the heat source in the image forming apparatus.

  In order to achieve the above object, the present invention provides an image forming apparatus including a fixing unit that fixes a non-fixed image on a transfer sheet using a heating unit that is heated by a heat source that can control the amount of generated heat and includes a temperature detection unit. The temperature of the heating means is periodically measured via the temperature detection unit, and the measured temperature detection data is sequentially stored in the storage unit, and a predetermined number of continuous temperature detection data is periodically stored from the storage unit. Sequentially acquired and averages the remaining temperature detection data excluding one or more temperature detection data in the descending order of temperature and one or more temperature detection data in descending order of temperature. And a controller that controls the actual temperature of the heating means by controlling the amount of heat generated by the heat source based on the averaged temperature detection data.

  The invention according to claim 2 is characterized in that the control unit sets the measurement period of the temperature detection data to 0.1 second or more and 0.5 second or less per time.

  According to a third aspect of the present invention, the control unit sequentially acquires a predetermined plurality of consecutive temperature detection data from the storage unit, and among the plurality of consecutive temperature detection data, the highest temperature side, the lowest The temperature of the heating means is averaged based on the remaining temperature detection data excluding a plurality of temperature detection data from the temperature side, and the heat generation amount of the heat source is controlled based on the averaged temperature detection data. It is characterized by controlling.

  The invention according to claim 4 is characterized in that the control unit sets the energization cycle per time when energizing the heat generating source of the heating means to 0.2 second or more and 0.5 second or less.

  The invention described in claim 5 is characterized in that the temperature detection unit is a non-contact type temperature detection unit.

  According to a sixth aspect of the present invention, the control unit is configured to sample the plurality of continuous temperature detection data that are sampled during the averaging process when the apparatus starts up and stands by when the high voltage system such as the charging unit / transfer unit is not operating. The plurality of consecutive temperature detections that are sampled during the averaging process during process adjustment or paper feeding, during operation of the high-pressure system, or by eliminating or reducing the number of temperature detection data and the number of temperature detection data to be excluded The number of data acquisition and the number of temperature detection data to be excluded are reset to a specified number.

  According to a seventh aspect of the present invention, there is provided a fixing method in which an unfixed image is fixed on a transfer paper by using a heating unit that is heated by a heat source that can control a heat generation amount and that has a temperature detection unit. The control performs temperature detection of the heating means via the temperature detection unit, and first periodically stores the temperature detection data periodically measured in the storage unit, and is periodically specified from the storage unit. A number of consecutive temperature detection data are sequentially acquired, and the remaining plurality of the temperature detection data except for one or more temperature detection data in descending order of temperature and one or more temperature detection data in order of increasing temperature. A second step of averaging the temperature detection data, and a third step of controlling the actual temperature of the heating means by controlling the amount of heat generated by the heat source based on the averaged temperature detection data. Characterized in that it comprises and.

  The invention according to claim 8 is characterized in that, in the measurement of the temperature detection data in the first step, the measurement cycle is 0.1 second to 0.5 second per time.

  According to the ninth aspect of the present invention, in the second step, a plurality of remaining temperature detections obtained by removing a plurality of temperature detection data from the highest temperature side and the lowest temperature side of the temperature detection data acquired from the storage unit. Averaging is performed based on the data.

  The invention according to claim 10 is characterized in that, in the third step, when the heat source is energized and controlled, the energization cycle per time is 0.2 seconds or more and 0.5 seconds or less. To do.

  The invention described in claim 11 is characterized in that, in the second step, the temperature detection data is measured using a non-contact type temperature detection unit.

  According to a twelfth aspect of the present invention, the number of continuous temperature detection data fetched in the first step is determined when the apparatus is in a stand-by state or in standby mode when the high-voltage system such as the charging unit / transfer unit is not operating. One of elimination or reduction is performed, and either the number of temperature detection data to be excluded in the averaging process in the second step is eliminated or reduced.

  According to the present invention, it is possible to improve the reliability of temperature detection and reduce power consumption even in non-contact temperature detection. Specifically, it enables temperature detection without the influence of noise, and also reduces the inrush power of the power value even when controlling the maximum execution power given to the heater, thereby reducing the power consumption and controlling these Is efficient and can improve reliability.

  That is, according to the first and seventh aspects of the present invention, when averaging the temperature detection data, one or more temperature detection data is excluded in descending order of temperature and one or more temperature detection data in order of decreasing temperature. This prevents large temperature changes that are affected by noise from high-pressure systems and averaged due to noise, and shifts and averages for each temperature detection data. The detection signal can be obtained in a short period, and thereby the reliability of temperature control can be improved.

  According to the second and eighth aspects of the invention, since the detection cycle of the temperature detection signal is set to 0.1 seconds or more, it is advantageous in terms of cost without increasing the load on the control unit (CPU or the like).

  In the inventions according to claims 3 and 9, since the processing becomes longer in time when the number of temperature detection data is increased, there may be a plurality of influences of high-pressure noise. Since multiple temperature detection data are excluded from the highest temperature side and the lowest temperature side respectively, a temperature detection signal that is more resistant to noise can be obtained in a short period, thereby further improving the reliability of temperature control. Can be made.

  According to the fourth and tenth aspects of the present invention, since the temperature detection signals can be aggregated in a short cycle according to the first and second aspects of the invention, the lighting cycle when the heat generating means generates heat is normally about 1 second. By reducing the power consumption to 0.5 seconds or less, the inrush power of the power value of the maximum execution power control can be suppressed, and the maximum power consumption can be reduced.

  According to the fifth and eleventh aspects of the present invention, since the temperature detection unit is non-contact, the actual temperature of the measurement object is determined by comparing the temperature of the measurement object with the temperature of itself. Alternatively, the actual temperature can be detected by performing the control 2 and the advantage of not scratching the heating means can be fully utilized.

  The invention described in claims 6 and 12 is characterized in that the control unit takes in and excludes a plurality of continuous temperature detection data to be sampled during the averaging process at the time of start-up and standby when the high-pressure system is not operating. Whether the number of detection data is eliminated or reduced, the number of continuous temperature detection data to be sampled and the temperature detection data to be excluded are sampled at the time of the averaging process during process adjustment or paper passing during high-pressure operation Therefore, the power consumption is greatly reduced and the control method is more efficient depending on the situation of the present apparatus.

  The image forming apparatus according to the first embodiment of the present invention will be described below with reference to FIGS. In this embodiment, a case where the image forming apparatus is applied to a copying machine is illustrated. FIG. 1 is an explanatory diagram for explaining the overall configuration of a copying machine as an image forming apparatus according to the present embodiment.

  As shown in FIG. 1, the copying machine Dp of the present embodiment includes at least an optical system Ops that optically reads an image of a document, an image read by the optical system Ops, or a job input from a communication unit or a transfer unit. (Original image: image forming command) or a memory (not shown: arbitrary memory) for storing a job (original image: image forming command) input from a storage medium (for example, a memory card or a CD-ROM), and optical An image created by creating an electrostatic latent image of an image read by the system Ops or a job (original image) stored in the memory (not shown) and developing it with a color toner to form a visible image. The image forming section 25 forms an image on the transfer paper P supplied from the paper supply tray 1 and manual feed tray 2 and the paper feed tray 1 or manual feed tray 2. The paper transfer unit 3 for transferring the visible image, the transfer belt (paper transfer system) 4 for transferring the transfer paper P on which the unfixed image is transferred by the paper transfer unit 3, and the transfer belt 4 And a fixing unit 10 for fixing an unfixed image on the transfer paper P.

First, as shown in FIG. 2, the fixing unit 10 includes a heat source (hereinafter referred to as a first heater) 55 such as a halogen heater or an IH heat source inside or outside a cylindrical cored bar 50 b. A fixing roller (heating means) 50 that covers a rubber layer such as a fluororesin on the surface layer of the core metal 50b, and two heat sources (hereinafter referred to as a second heating source) such as a halogen heater and an IH heating source inside or outside the metal pipe 60b. , Which is called a third heater) 65, 66, and is stretched around the fixing roller 50 and the heating roller 60. For example, a metal film such as Ni or SUS, PI, PAI, etc. A heat-resistant endless fixing belt (heating means) 40 provided with a surface layer of, for example, a fluororesin on a base material of silicon and a halogen heater or IH inside or outside a cylindrical cored bar 70b A heating source (hereinafter referred to as a fourth heater) 75 such as a heat source is provided, and a surface layer of the cored bar 70b is coated with a rubber layer such as a fluororesin, and the fixing belt 40 is pressed together with a pressing force of a pressing means (not shown). A pressure roller (pressure means: heating means) 70 is provided between the fixing belt 40 and a predetermined nip width between the fixing belt 50 and pressing force applied to the fixing roller 50.
In addition to the halogen lamp and the IH heating, any heat source of any configuration such as a resistance heat generation method may be adopted as each heat source.

Secondly, the fixing unit 10 is in the vicinity of the outer surface of the fixing belt 40 and near the fixing roller 50, and the non-contact type temperature sensor 53 positioned near the heating roller 60. Temperature sensor 63 and a contact-type temperature sensor 73 located on a part of the outer surface of the pressure roller 70.
For example, a thermopile or an infrared thermistor is suitable for the non-contact type temperature sensors 53 and 63, and a normal thermistor may be used for the contact type temperature sensor 73, for example.
The temperature detection outputs of the non-contact type temperature sensors 53 and 63 and the temperature detection output of the contact type temperature sensor 73 are respectively input to the control unit 81 of the control system shown in FIG. The control system will be described later.

  The fixing roller 50 and the pressure roller 70 may be configured not to include a heat source, and the configuration of the fixing unit 10 may include a heating roller having a heat source without using the fixing belt 40, and a heating roller. A configuration in which a temperature sensor is appropriately provided in a pair of configurations with a pressure roller that applies a pressing force by a pressure unit may be used.

On the other hand, the copying machine Dp receives a main body paper discharge unit (paper transfer system) 5 for discharging the transfer paper P after image fixing on the downstream side of the fixing unit 10, and the transfer paper P discharged from the main body paper discharge unit 5. And a paper discharge tray 6 to be accommodated.
The copying machine Dp generally has the above-described configuration. In addition, for example, various touch keys as an operation system, a display (touch panel) for operation guidance, and other various configurations necessary for the copying machine Dp are provided. Detailed description is omitted.

As a general operation of the copying machine Dp, when an image from the optical system Ops or an image (original image) stored in a memory (not shown) is acquired, the image forming unit 25 is activated, for example, an image carrier. After forming an electrostatic latent image corresponding to the image and developing it to form a visible image, the transfer paper P fed from the paper feed tray 1 or the manual feed tray 2 by the paper transfer roller 3 is used. An unfixed image based on a visible image is transferred to the surface of the sheet.
Subsequently, the transport belt 4 feeds the transfer paper P on which an unfixed image is formed into the nip of the fixing unit 10, and the fixing unit 10 applies heat to the transfer paper P from the fixing belt 40 and the pressure roller 70, and A pressing force from the pressure roller 70 is applied to fix the unfixed image on the fixing paper P.
Then, the transfer paper P on which the semi-permanent image is fixed passes through the main body discharge unit 5 and is discharged to the discharge tray 6 to complete one copy cycle. At this point, the image carrier is subjected to a cleaning process by the cleaning means and proceeds to the next operation.

  The control system of the copying machine Dp is outside the fixing unit 10, and as shown in FIG. 3, for example, a control unit that controls the entire copying machine Dp including the first to fourth heaters 55, 65, 66, 75 using a CPU. 81, a program memory 82 that stores a control program for operating the control unit 81, and a plurality of temperature sensors 53, 63, and 73 continuously detected by the control unit 81 at intervals of, for example, 0.1 seconds And a temperature memory (storage unit) 83 for storing the temperature detection signal.

First, the control unit 81 synchronizes with the clock signal, for example, according to settings, a plurality of temperature detection signals (A, B, C) continuously detected by the temperature sensors 53, 63, 73 at a cycle of 0.1 seconds. ,..., Q,... (See FIG. 4) are sequentially stored in a predetermined area of the temperature memory 83.
For example, as shown in FIG. 4, the control unit 81 secondly sets, for example, A, B, C as each temperature value data based on each temperature detection signal sequentially detected by the temperature sensor 53 with a period of 0.1 second, for example. , D, E, F, G, H, I, J, K, L, M, N, O, P, Q,..., Each of which is precisely a temperature value (actual temperature X) as shown in FIG. When temperature value data having different values are stored in the temperature memory 83, for example, among the ten temperature value data from A to J, the temperature value data of the highest temperature, for example B, and the temperature value data of the lowest temperature, for example, F are excluded. , B and F other than A to J (the number of objects to be calculated) are averaged and calculated, and the temperature of the first heater 55 of the fixing roller 50 is set to a predetermined target temperature based on the average value. To control.
Subsequently, the control unit 81 obtains the highest temperature, for example, G temperature value data and the lowest temperature, for example, M temperature value data among the latest ten temperature value data from E to N after 0.4 seconds, for example. The average value of eight temperature values (number of calculation targets) from E to N other than G and M is calculated and obtained, and the temperature of the first heater 55 of the fixing roller 50 is determined based on the average value. Control to target temperature. Thereafter, the same processing is repeated every 0.4 seconds.

  In addition, the control unit 81 performs the same averaging process except for the highest temperature and the lowest temperature on the temperature detection data sequentially detected from the temperature sensors 63 and 73 with a period of 0.1 second, and the second and second 3. Control of the fourth heaters 65, 66, 75 is also performed.

  However, the temperature detection cycle is not limited to 0.1 seconds, and may be a cycle of 0.2 seconds, 0.3 seconds, 0.4 seconds, 0.5 seconds, or the like. Also, the timing period of the averaging process is not limited to a period of 0.4 seconds, and an arbitrary timing period may be used as appropriate.

Next, an aspect of the operation of the control unit 81 accompanying the execution of the control program of the present embodiment will be described.
(Step 101) When an operation of turning on the main power supply is detected, power is supplied to the essential parts of the copying machine Dp including the fixing unit 10 to start up, that is, a warm-up mode is executed.
(Step 102) For example, power is supplied to the first to fourth heaters 55, 65, 66, and 75, and temperature detection signals from the temperature sensors 53, 63, and 73 are acquired, for example, every 0.1 period.
(Step 103) Each temperature detection signal acquired in Step 102 is converted into a numerical value (data) and stored in the temperature memory 83.
(Step 104) It is determined whether 0.4 seconds have elapsed since the acquisition of the first temperature detection signal, or whether 0.4 seconds have elapsed since the previous 0.4 seconds.
(Step 105) If it is determined in step 103 that 0.4 seconds have elapsed, it is determined whether or not the current time is during process adjustment or paper passing, which is during operation of the high-pressure system. In the case of Yes, the number of consecutive temperature detection data to be sampled and the number of temperature detection data to be excluded to be sampled in the averaging process are set to a predetermined number (number of calculation targets). If no, the process moves to the next step 106.
(Step 106) It is determined whether or not the present time is a stand-by state or a stand-by state when the high-voltage system such as the charging unit / transfer unit is not operating. In the case of Yes, either the number of continuous temperature detection data to be sampled to be sampled during the averaging process or the number of temperature detection data to be excluded is either eliminated or reduced. If no, the process returns to step 104.
(Step 107) Thus, if the answer is Yes in Step 105, then a predetermined number of temperature detections among the plurality of temperature detection data corresponding to each of the temperature sensors 53, 63, 73 stored in the temperature memory 83 are performed. Acquire data and exclude the temperature detection data of each maximum temperature and minimum temperature (or multiple from the highest on the highest temperature side, multiple from the lowest on the lowest temperature side), and each of the remaining multiple (number of calculation objects) ) Calculate the average value of the temperature detection data. See Figure 4 for the formula.
(Step 108) The average value is stored in a predetermined memory as needed. The contents of the average value of the memory are rewritten at least every 0.4 seconds.
(Step 109) The heating values (energization) of the first to fourth heaters 55, 65, 66, 75 are controlled (for example, control to the reload temperature) using the average value of the temperature detection data stored in the memory. . In the energization control of the first to fourth heaters 55, 65, 66, and 75, the energization cycle (lighting cycle) per time is set to 0.2 seconds to 0.5 seconds.
(Step 110) It is determined whether or not the temperature of the fixing belt 40 has reached a reload temperature necessary for fixing an unfixed image. If Yes, the warm-up mode is terminated and the copy start button is detected and the copy operation is started. If No, the new average value stored in the memory at any time in step 108 is read and the operation (energization) of the first to fourth heaters 55, 65, 66, 75 is controlled using this new average value. To do. Also in this case, when controlling the energization of the first to fourth heaters 55, 65, 66, and 75, the energization cycle per time is set to 0.2 seconds to 0.5 seconds.
(Step 111) It is determined whether or not the copy operation has been completed. If the copy operation has been completed, this flow is terminated and the standby mode is entered.
(Step 112) For example, when it is detected that the copy operation is set or the copy start button is pressed, the process proceeds to Step 102.
(Step 113) On the other hand, if the answer is Yes in Step 106, then, along with any setting to eliminate or reduce the number of consecutive temperature detection data fetches and the number of temperature detection data to be excluded Continue standing up or waiting. Then, the process returns to step 103.

In this embodiment, it is assumed that a plurality of continuous temperature detection data is affected by noise from a high voltage system such as a charger or a transfer device, or noise caused by the harness passing through the vicinity of the high voltage system. However, the averaging process is performed based on the remaining multiple (number of calculation target) temperature detection data excluding the temperature detection data of the highest temperature and the lowest temperature that change most under the influence of noise. Since the heat generation amount of each heater 55, 65, 66, 75 is controlled, as a result, unnecessary fluctuation of the temperature detection signal is prevented to improve the reliability of temperature detection, and the control of each heater 55, 65, etc. Reliability can also be improved.
In this embodiment, since the temperature detection cycle is set to 0.1 second, the above-described averaging process can be performed without increasing the CPU load, that is, even if the CPU is not extremely fast. It is also advantageous in terms of cost.
In the present embodiment, the non-contact type temperature sensors 53 and 63 are used. However, as shown in FIG. 6, the non-contact type temperature sensor has a gradual temperature-resistance characteristic from a high temperature region to a low temperature region. A simple curve is drawn and the rate of change is small. Therefore, the above averaging process associated with the temperature detection based on the comparison between the temperature measurement of itself and the temperature measurement of the object to be measured (such as the fixing belt 40) is improved in reliability. Is preferable.

  When a non-contact type temperature sensor is used, a control circuit that detects the actual temperature by comparing its own temperature measurement with the temperature measurement of the object to be measured (such as the fixing belt 40) is required outside the fixing unit 10. However, detailed description of the control circuit is omitted.

  Next, a copying machine as an image forming apparatus according to a second embodiment of the present invention will be described. The copier according to the present embodiment also has the same configuration as that shown in FIGS. 1 to 4 and will not be described in detail.

In the case of the present embodiment, the processing content of the control unit 81 shown in FIG. 3 is slightly different. In other words, if the total number of temperature detection data is increased, the load required for the averaging process becomes longer in time, so that the influence of noise from high-voltage systems such as chargers and transfer units is also affected by the total number. There is.
For this reason, the control unit 81 according to the present embodiment, when averaging a plurality of temperature detection data acquired from the temperature sensors 53, 63, 73, for example, every 0.1 second, has a third highest value from the highest temperature. Exclude temperature data up to the temperature and exclude the temperature data from the lowest temperature to the third lowest temperature, and then calculate the average value of the predetermined multiple (number of calculation objects) temperature data each remaining, Based on the average value, the operation of the first to fourth heaters 55, 65, 66, 75 is controlled to a predetermined target temperature.

  In the present embodiment, the temperature data from the highest temperature to the third highest temperature and the temperature data from the lowest temperature to the third lowest temperature, which largely reflect the influence of noise, are excluded, thereby being resistant to noise. Since the temperature detection signals are aggregated and averaged in a short cycle, unnecessary changes in temperature detection are prevented to further improve the reliability of temperature detection, and the reliability of control of each heater 55, 65, etc. is further increased. Can be improved.

  The number of temperature data excluded during averaging is not limited to a total of six from the highest temperature to the third highest temperature and from the lowest temperature to the third lowest temperature. It may be set to.

  Next, a copying machine as an image forming apparatus according to a third embodiment of the present invention will be described. The copier according to the present embodiment also has the same configuration as that shown in FIGS. 1 to 4 and will not be described in detail.

Also in the case of the present embodiment, the processing contents of the control unit 81 shown in FIG. 3 are slightly different. That is, when the energization period to each heater 55, 65, 66, 75 is increased when controlling the execution power for operating the first to fourth heaters 55, 65, 66, 75, as shown in FIGS. In addition, a large heater rush power is generated for each execution power.
For example, as shown in FIG. 8, the heater inrush power is Z ₂ in the energization cycle 2 per _second , for example, but the heater inrush power is greater than Z _{2 in} the energization cycle 1 of 0.5 seconds or less, for example. small Z _1, and the better to reduce the energization period heater rush power amount, it is possible to reduce the maximum power consumption.
Therefore, when the control unit 81 of the present embodiment controls the execution power for operating the first to fourth heaters 55, 65, 66, 75, the energization cycle of each heater 55, 65, 66, 75 is set to 0. 0. Set to 2 seconds or more and 0.5 seconds or less.

  In the present embodiment, the energization cycle of the first to fourth heaters 55, 65, 66, and 75 is normally set to about 1 second, and is set to 0.2 seconds or more and 0.5 seconds or less. The inrush power of the power value of the execution power control can be reduced, and the maximum power consumption can be reduced.

  Next, a copying machine as an image forming apparatus according to a fourth embodiment of the present invention will be described. The copier according to the present embodiment also has the same configuration as that shown in FIGS. 1 to 4 and will not be described in detail.

  Also in the case of the present embodiment, the processing content of the control unit 81 shown in FIG. 3 is partially different. That is, the high-pressure system that generates noise is turned off at the time of stand-up or standby, and conversely, the high-pressure system is turned on during process adjustment or paper feeding. Therefore, as shown in FIG. 9, it is possible to eliminate or reduce the number of temperature detection data to be averaged or the number of temperature detection data to be excluded at the start-up or standby time when the high-pressure system is turned off.

The control unit 81 of the present embodiment is configured so that the temperature sensors 53, 63, and 73 are used during the above-described averaging process at the time of start-up (warm-up mode) and standby when the high-voltage system such as the charging unit / transfer unit is not operating. The number of continuous temperature detection data sampled from the first to the temperature memory 83 and the number of temperature detection data to be excluded on the highest temperature side and the lowest temperature side are set to either elimination or reduction.
The control unit 81 captures a plurality of continuous temperature detection data sampled from each of the temperature sensors 53, 63, 73 during the above-described averaging process at the time of process adjustment, which is during operation of the high-pressure system, or during paper feeding. In addition, the number of temperature detection data to be excluded is set to a predetermined number (the number of calculation targets) as in the first or second embodiment.

In the present embodiment, at the time of start-up and stand-by when the high-pressure system is not in operation, the number of temperature detection data fetched from the temperature sensors 53, 63, 73 to the temperature memory 83 during the above-described averaging process, In addition, since the number of the temperature detection data to be excluded on the maximum temperature side and the minimum temperature side is set to be either eliminated or reduced, the period for acquiring the temperature detection signal can be further shortened. It is possible to further improve the control efficiency of the fourth heaters 55, 65, 66, 75.
Accordingly, there is an advantage that it is possible to improve the efficiency of the control method of the first to fourth heaters 55 depending on the situation of the copying machine Dp or the fixing unit 10.

  It should be noted that the technical idea of the present invention can be applied to a simultaneous transfer fixing technique in which a visible image (that is, an unfixed image) formed in the image forming unit is transferred to a transfer sheet and fixed.

  The present invention can be used as an image forming apparatus for a fax machine, a printer, or the like in addition to a copying machine.

1 is an explanatory diagram illustrating an overall configuration of a copying machine as an image forming apparatus according to each embodiment of the present invention. FIG. FIG. 2 is an explanatory diagram illustrating a configuration of a fixing unit of the copying machine. FIG. 2 is a block diagram illustrating a configuration example of a control system of the copying machine. It is explanatory drawing explaining the relationship between memory | storage of several continuous temperature detection data detected for every period of 0.1 second, and an averaging process. It is a graph explaining an example of the noise which affects a temperature detection signal. It is a graph which shows the characteristic of the temperature versus resistance of a non-contact-type temperature sensor. It is a graph which shows the relationship between the lighting period of the execution electric power which operates a heater, and an inrush voltage. It is a graph which shows two specific examples of a lighting period. FIG. 6 is a graph showing an example in which the temperature detection signal is taken in at different times when rising, during process adjustment, during standby, and during paper feeding.

Explanation of symbols

Dp ... Copier Ops ... Optical system P ... Transfer paper 1 ... Feed tray 2 ... Bypass tray 3 ... Paper transfer section 4 ... Conveying belt 5 ... Main body paper discharge section 6 ... Discharge tray 10 ... Fixing unit 25 ... Image production Image unit 40... Fixing belt (heating means)
50. Fixing roller (heating means)
53 ... Temperature sensor (temperature detector)
55 ... 1st heater 60 ... Heating roller (heating means)
63 ... Temperature sensor (temperature detector)
65 ... second heater 66 ... third heater 70 ... pressure roller (pressure means: heating means)
73 ... Temperature sensor (temperature detector)
81 ... Control unit 82 ... Program memory 83 ... Temperature memory (storage unit)

Claims (12)

In an image forming apparatus including a fixing unit that fixes a non-fixed image on a transfer sheet using a heating unit that is heated by a heat source that can control the amount of generated heat, and that includes a temperature detection unit.
While periodically measuring the temperature of the heating means via the temperature detection unit, and storing the measured temperature detection data in the storage unit sequentially,
Periodically, a predetermined number of continuous temperature detection data is sequentially acquired from the storage unit, and one or more temperature detection data in the descending order of temperature and one or more temperature detections in the order of low temperature among the acquired temperature detection data. Average the remaining multiple temperature detection data excluding the data,
An image forming apparatus comprising: a control unit configured to control an actual temperature of the heating unit by controlling a heat generation amount of the heat generation source based on the averaged temperature detection data.   The image forming apparatus according to claim 1, wherein the control unit sets the measurement period of the temperature detection data to 0.1 second or more and 0.5 second or less per time. The control unit sequentially obtains a predetermined plurality of continuous temperature detection data from the storage unit, and among the plurality of continuous temperature detection data, a plurality of temperature detection data from the highest temperature side and the lowest temperature side, respectively. Based on the remaining temperature detection data excluding,
Controlling the actual temperature of the heating means by controlling the calorific value of the heat source based on the averaged temperature detection data;
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.   4. The control unit according to claim 1, wherein an energization cycle per time when the heating unit of the heating unit is energized and controlled is 0.2 seconds or more and 0.5 seconds or less. 5. The image forming apparatus according to one.   The image forming apparatus according to claim 1, wherein the temperature detection unit is a non-contact type temperature detection unit. The control unit is configured to sample the plurality of continuous temperature detection data to be sampled and to exclude the temperature at the time of start-up and standby of the high-voltage system such as the charging unit / transfer unit during standby. Whether to reduce or reduce the number of detected data,
At the time of process adjustment or paper passing during operation of the high-pressure system, the number of continuous temperature detection data to be sampled and the number of temperature detection data to be excluded to be sampled during the averaging process are reset to a predetermined number. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. In a fixing method in which an unfixed image is fixed on a transfer sheet using a heating unit that is heated by a heat source that can control the amount of heat generation and includes a temperature detection unit.
Control of the amount of heat generated in the heat source is
A first step of performing temperature detection of the heating means via the temperature detection unit and sequentially storing temperature detection data periodically measured in the storage unit;
A predetermined number of continuous temperature detection data is periodically acquired sequentially from the storage unit, and one or more temperature detection data in the descending order of temperature among the acquired temperature detection data and one or more temperature detections in descending order of temperature. A second step of averaging the remaining plurality of temperature detection data excluding the data;
And a third step of controlling the actual temperature of the heating means by controlling the amount of heat generated by the heat source based on the averaged temperature detection data.   The fixing method according to claim 7, wherein the temperature detection data is measured in the first step at a measurement cycle of 0.1 seconds to 0.5 seconds.   In the second step, averaging is performed based on a plurality of remaining temperature detection data obtained by removing a plurality of temperature detection data from the highest temperature side and the lowest temperature side among the temperature detection data acquired from the storage unit. The fixing method according to claim 7, wherein the fixing method is characterized in that:   10. The method according to claim 7, wherein, in the third step, when energizing and controlling the heat source, the energization cycle per time is set to 0.2 seconds to 0.5 seconds. The fixing method according to one.   The fixing method according to claim 7, wherein in the second step, the temperature detection data is measured using a non-contact temperature detection unit. Whether the number of continuous temperature detection data fetched in the first step is eliminated or reduced when the apparatus is in a stand-by state or when waiting for a high-voltage system such as a charging unit / transfer unit. The method according to any one of claims 7 to 11, wherein the number of temperature detection data excluded in the averaging process in the second step is eliminated or reduced. Fixing method.

Images