JP2014164183A - Fixing device, image forming apparatus, fixing control method, and fixing control program - Google Patents

Abstract

The present invention raises a fixing member to a fixing temperature quickly and inexpensively while suppressing overshoot.
A fixing unit includes a fixing control unit configured to control a fixing roller based on a detected temperature of a fixing roller detected by a temperature detecting unit when a fixing heater that heats the fixing roller is started up. Then, the power supply unit 101 turns on / off the power supplied to the fixing heater 51h via the switch unit 102, and when the energization of the fixing heater 51h is started, the calculation unit 108 receives the detected temperature based on the detected temperature. The input voltage value to the fixing heater 51h is predicted. The control unit 103 controls the rotation of the fixing roller 51 via the rotation driving unit 105 based on the voltage value and the detected temperature detected by the temperature detecting unit 110.
[Selection] Figure 2

Description

  The present invention relates to a fixing device, an image forming apparatus, a fixing control method, and a fixing control program, and more specifically, a fixing device, an image forming apparatus, and a fixing device that quickly and inexpensively raise a fixing member while suppressing overshoot. The present invention relates to a control method and a fixing control program.

  Conventionally, as a method of thermally fixing an image (hereinafter referred to as toner image) of a recording material such as toner (hereinafter simply referred to as toner) formed on a recording medium such as paper or film, generally, A heat fixing method is used in which the toner is melted by heating and pressurizing to thermally fix the toner onto a recording medium. In this heat fixing method, heat fixing is performed by passing a recording medium on which a toner image is transferred through a fixing roller heated by a fixing heater or a nip portion between a fixing belt and a pressure roller.

  In order to improve the usability of the fixing device of the heat fixing system, quick start-up and high fixing speed are required.

  Conventionally, a technology has been proposed in which the fixing device detects the current flowing through the fixing heater when the fixing heater is started up by a current detection circuit and performs duty control on the input power to the fixing heater (see Patent Document 1). .

  That is, in an image forming apparatus equipped with a fixing device or a fixing device, an AC commercial power source that is a power supply source of a fixing heater has an allowable range of a voltage range of 85 V to 140 V at an input voltage. Therefore, even if the initial duty value to the fixing heater is fixed, the initial offset power actually supplied to the fixing heater varies greatly depending on the fluctuation of the input voltage. If the input voltage is low, it takes a longer time than the preset scheduled time to reach the target temperature after the initial offset power is applied. In addition, when the input voltage is high, the temperature of the fixing heater greatly overshoots from the target temperature, and the fixed image is hot offset (the toner melts too much and adheres to the fixing roller and fixing belt, and the surface of the recording medium is stained) ) And other problems that are judged as malfunctions such as high-temperature abnormalities.

  Therefore, the conventional technology described in the above publication detects overcurrent and power shortage by detecting the current flowing through the fixing heater and controlling the input power even if the input power supply fluctuates when the fixing heater is started up. The temperature control which suppressed is carried out.

  However, in the prior art described in the above publication, the current flowing through the fixing heater is detected by the current detection circuit, and the energization to the fixing heater is controlled based on the detection result of the current detection circuit. There is a problem that the circuit configuration is enlarged, the mounting area of the components is increased, and the cost is increased. This problem also occurs when the energization voltage to the fixing heater is detected by the voltage detection circuit and the energization control to the fixing heater is performed.

  Therefore, an object of the present invention is to quickly heat a fixing member to a target temperature while suppressing overshoot with an inexpensive and simple configuration.

In order to achieve the above object, the fixing device according to claim 1 is heated to a predetermined target temperature by the heating means, and heats the recording medium on which the recording material image is transferred to the recording medium. A fixing member for fixing the recording material image; and a rotation driving means for rotating the fixing member;
A temperature detecting means for detecting the temperature of the fixing member; and, based on the detected temperature of the temperature detecting means, the power supply to the heat generating means is controlled by using an external power supply supplied from outside. When the energization of the temperature control means for controlling the temperature of the heater and the heat generation means is started, the voltage prediction for predicting the voltage value of the external power supply power based on the detected temperature detected by the temperature detection means for each predetermined observation period And a rotation control means for controlling the rotation of the fixing member by the rotation driving means based on the voltage value predicted by the voltage prediction means and the detected temperature detected by the temperature detection means. It is said.

  According to the present invention, it is possible to quickly heat the fixing member to the target temperature while suppressing overshoot with an inexpensive and simple configuration.

1 is a schematic configuration diagram of a color image forming apparatus to which an embodiment of the present invention is applied. FIG. 3 is a circuit configuration diagram of a fixing control unit. The figure which shows the relationship between the input voltage at the time of starting, and the temperature of a fixing roller. 7 is a flowchart showing fixing heater start-up processing.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, since the Example described below is a suitable Example of this invention, various technically preferable restrictions are attached | subjected, However, The range of this invention is unduly limited by the following description. However, not all the configurations described in the present embodiment are essential constituent elements of the present invention.

  1 to 4 are diagrams illustrating an embodiment of a fixing device, an image forming apparatus, a fixing control method, and a fixing control program according to the present invention. FIG. 1 illustrates a fixing device, an image forming apparatus, and a fixing control according to the present invention. 1 is a schematic configuration diagram of a color image forming apparatus 1 to which an embodiment of a method and a fixing control program are applied.

  In FIG. 1, a color image forming apparatus 1 includes a paper feed unit 10, a paper feed transport unit 20, a paper discharge transport unit 30, a double-sided transport unit 40, a fixing unit 50, an image forming unit 60, a manual feed in a main body housing 2. A paper feed unit 80, a control board 90, and the like are accommodated, a paper discharge tray 3 is provided at the top of the main body housing 2, and an operation display unit (not shown) is provided.

  In the following description, it is assumed that the color image forming apparatus 1 prints print data of a print job received from a host device such as an external computer via a network such as a LAN (Local Area Network). In addition, an image data input unit such as a scanner unit or a facsimile unit may be provided, and print processing (image formation processing) may be performed based on image data from these image data input units.

  The paper supply unit 10 includes a paper supply tray 11, a paper supply roller 12, a separation pad (not shown), and the like, and a plurality of sheets (recording medium) P are stored in the paper supply tray 11. The sheet feeding unit 10 separates the uppermost sheet P in the sheet feeding tray 11 one by one by the sheet feeding roller 12 and the separation pad, and sends the separated sheet P to the sheet feeding and conveying unit 20.

  The manual paper feed unit 80 includes a manual tray 81 attached to the main body housing 2 so as to be rotatable by a predetermined angle, a manual paper feed roller 82 that feeds the paper P on the manual tray 81 to the paper feed conveyance unit 20, a manual bottom plate 83, and the like. A paper sensor (not shown) is provided.

  When manually feeding the paper P, the manual paper feed unit 80 becomes usable when the manual tray 81 accommodated in the main body housing 2 is opened at a predetermined angle by the user, and the manual bottom plate The manual paper feed roller 82 feeds the paper P inserted by the user onto the paper feeding / conveying unit 20.

  The paper feed conveyance unit 20 is connected to the paper discharge conveyance unit 30 and conveys the paper P sent out from the paper supply unit 10 to the paper discharge conveyance unit 30. A registration sensor 21 and a registration roller 22 are arranged along the conveyance direction (sub-scanning direction) of the paper P. The registration sensor 21 includes the paper supply unit 10 and the manual paper supply unit 80. The paper P conveyed to the registration roller 22 on the paper feeding / conveying unit 20 is detected. The registration roller 22 temporarily stops the conveyed paper P based on the detection result of the paper P by the registration sensor 21, and then adjusts the transfer timing of the toner image onto the paper P by the image forming unit 60. Drive control is performed so as to resume conveyance.

  The paper discharge conveyance unit 30 is provided with a fixing unit 50, a paper discharge sensor 31, a paper discharge roller 32, and the like. The fixing unit 50 transfers the toner image (recording material image) by the image forming unit 60. The paper P is conveyed while being heated and pressurized to fix the toner image on the paper P. The paper discharge conveyance unit 30 conveys the paper P on which the toner image is fixed by the fixing unit 50 to the paper discharge roller 32, and the paper discharge sensor 31 transfers the paper P conveyed from the fixing unit 50 to the paper discharge roller 32. Then, the paper discharge roller 32 discharges the paper P on which the toner image has been fixed onto the paper discharge tray 3.

  Further, the paper discharge conveyance unit 30 is connected to the double-sided conveyance unit 40 in the vicinity of the position where the paper discharge sensor 31 on the downstream side of the fixing unit 50 is disposed. 20 is connected in the vicinity of the sheet feeding unit 10.

  In the double-sided printing mode, the color image forming apparatus 1 stops driving the paper discharge roller 32 when the trailing edge of the paper P on which printing on one side has completed passes through the paper discharge sensor 31, and then discharges the paper. The roller 32 is driven reversely to feed the paper P into the double-sided conveyance unit 40.

  The double-sided conveyance unit 40 includes a double-sided roller 41, a double-sided sensor 42, and the like, and sends the paper P sent by the paper discharge roller 32 to the paper feeding / conveying unit 20 by the double-sided roller 41 while reversing the front and back surfaces. At the same time, the paper P is detected by the double-side sensor 42. For example, a reflection type or a transmission type photocoupler is used as the registration sensor 21, the paper discharge sensor 31, the double-side sensor 42, the paper sensor of the manual paper feed unit 80, and the like.

  The paper feed conveyance unit 20 conveys the paper P sent from the double-sided conveyance unit 40 to the paper discharge conveyance unit 30 after being subjected to image formation by the image forming unit 60 via the registration rollers 22.

  The image forming unit 60 is a so-called tandem type image forming unit, and is formed along an intermediate transfer belt 61 that is formed in an endless belt-like ring shape and stretched in a substantially horizontal direction, and the intermediate transfer belt 61. The developing units 62K, 62M, 62C, 62Y for the respective colors K (black), M (magenta), Y (yellow), and C (cyan), the exposure unit 63, and the toner mark (Toner Mark: TM) A sensor 64, a waste toner box 65, an intermediate transfer belt cleaner 66 and a secondary transfer roller 67 are provided. The intermediate transfer belt (intermediate transfer medium) 61 is stretched between a secondary transfer driving roller 68 and a tension roller 69. ing. The color image forming apparatus 1 is provided with CMYK primary transfer rollers 70K, 70M, 70C, and 70Y corresponding to the developing units 62K, 62M, 62C, and 62Y with the intermediate transfer belt 61 interposed therebetween. .

  Each of the developing units 62K, 62M, 62C, and 62Y has chargers 72K, 72M, 72C, and 72C, respectively, centering on photoreceptors (image carriers) 71K, 71M, 71C, and 71Y that are driven to rotate clockwise in FIG. 72Y, developing units 73K, 73M, 73C, and 73Y, cleaning units 74K, 74M, 74C, and 74Y, and a developing roller, a supply roller, a developing blade, a cleaner blade, and the like that are not provided with symbols are provided as a unit. In addition, toner storage portions 75K, 75M, 75C, and 75Y that supply toner to the developing portions 73K, 73M, 73C, and 73Y are disposed.

  Each of the developing units 62K, 62M, 62C, and 62Y is opposed to the primary transfer rollers 70K, 70M, 70C, and 70Y for each color with the photoreceptors 71K, 71M, 71C, and 71Y sandwiching the intermediate transfer belt 61. In a state where contact is possible, it is housed and mounted in the main body housing 2 of the color image forming apparatus 1, and the photoreceptors 71K, 71M, 71C, 71Y of the developing units 62K, 62M, 62C, 62Y and the primary transfer roller. The intermediate transfer belt 61 is conveyed between 70K, 70M, 70C, and 70Y. The primary transfer rollers 70K, 70M, 70C, and 70Y are used to transfer the toner images on the photoreceptors 71K, 71M, 71C, and 71Y to the intermediate transfer belt 61, but the primary transfer at the transfer operation timing is performed. Only the rollers 70K, 70M, 70C, and 70Y are positioned at positions facing the photoconductors 71K, 71M, 71C, and 71Y, and the primary transfer rollers 70K, 70M, 70C, and 70Y other than the transfer operation timing are the photoconductor 71K, Retreat to a position separated from the position facing 71M, 71C, 71Y.

  The exposure unit 63 irradiates the corresponding color photoconductors 71K, 71M, 71C, and 71Y with exposure light Lk, Lm, Lc, and Ly for each color modulated by the image data of each color.

  The image forming unit 60 sensitizes each color toner by the developing units 73K, 73M, 73C, and 73Y while rotating the photoconductors 71K, 71C, 71M, and 71Y on which the electrostatic latent images are formed by the exposure unit 63 in the clockwise direction. The electrostatic latent image is developed on each of the bodies 71K, 71C, 71M, and 71Y to form toner images of the respective colors, and primary transfer is performed on the photoreceptors 71K, 71C, 71M, and 71Y on which the toner images of the respective colors are formed. Rollers 70K, 70M, 70C, and 70Y sequentially superimpose and transfer onto the intermediate transfer belt 61 to form a color toner image. The image forming unit 60 further rotates the photoconductors 71K, 71C, 71M, and 71Y to which the toner image has been transferred to remove residual toner by the cleaning units 74K, 74M, 74C, and 74Y, and then again charges the charger 72K. , 72M, 72C, 72Y and used for image formation.

  The image forming unit 60 sends the waste toner removed by the cleaning units 74K, 74M, 74C, and 74Y to the waste toner box 65, and the color image forming apparatus 1 indicates that the waste toner in the waste toner box 65 is full. Is detected by a waste toner full detection sensor (not shown), a message prompting replacement with a new waste toner box 65 is output to the operation display unit.

  Each of the developing units 62K, 62M, 62C, and 62Y is provided with a toner sensor (not shown) that detects whether or not the toner has become a certain amount or less, and the toner sensors are the developing units 62K, 62M, When it is detected that the toner in 62C and 62Y has become a certain amount or less, the toner is supplied from the toner containers 75K, 75M, 75C, and 75Y to the developing units 62K, 62M, 62C, and 62Y in which the toner is reduced.

  The intermediate transfer belt 61 is driven to rotate counterclockwise in FIG. 1 by a secondary transfer drive roller 68 that is driven to rotate by a drive motor (not shown), and the secondary transfer drive roller 68 is connected to the secondary transfer roller 67. The toner image on the intermediate transfer belt 61 is transferred by the transfer potential of the secondary transfer roller 67 to the paper P that has been conveyed from the registration roller 22 therebetween.

  The fixing unit 50 includes a fixing roller 51 and a pressure roller 52 that are rotatably arranged. The fixing roller (fixing member) 51 includes a built-in fixing heater as shown in FIG. (Heat generating means) Heated to a predetermined fixing temperature (target temperature) by 51h. When the sheet P on which the toner image is transferred is conveyed between the fixing roller 51 and the pressure roller 52, the fixing unit 50 is heated and fixed by the fixing roller 51 and the pressure roller 52 that are heated to the fixing temperature. The paper P is conveyed while being pressurized, and the toner image on the paper P is fixed to the paper P.

  As described above, the paper discharge conveyance unit 30 conveys the paper P on which the toner image is fixed by the fixing unit 50 to the paper discharge roller 32, and the paper P conveyed from the fixing unit 50 to the paper discharge roller 32. When the paper discharge sensor 31 detects and one-sided printing or printing on the back side of double-sided printing is completed, the paper discharge roller 32 discharges the paper P on which the toner image has been fixed onto the paper discharge tray 3.

  The control board 90 is equipped with a controller and the like, and various sensors such as an operation display unit, a registration sensor 21, a paper discharge sensor 31, a double-side sensor 42, and a paper sensor of the manual feed tray 81 are connected to the controller. . The controller includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and controls each part of the color image forming apparatus 1 based on a basic program in the ROM. Basic processing as the image forming apparatus 1 is executed.

  The fixing unit (fixing device) 50 includes a fixing control unit 100 as shown in FIG. The fixing control unit 100 includes a power supply unit 101, a fixing heater 51h, a switch unit 102, a control unit 103, a zero cross circuit 104, a rotation driving unit 105, a thermistor 106, a temperature detection circuit 107, a calculation unit 108, a storage unit 109, and the like. ing.

  The power supply unit 101 is supplied with commercial power having an alternating current (AC) rating of 100 V and supplies the commercial power as it is to the fixing heater 51h as fixing power. If the commercial power supply is a 100V system, the voltage value fluctuation tolerance range is generally in the range of 85V to 115V. The commercial power supply input to the color image forming apparatus 1 fluctuates not only due to fluctuations in the commercial power supply itself, but also due to the local circumstances where the color image forming apparatus 1 is installed, the environment of surrounding equipment, and the like.

  The switch unit 102 uses a high-speed semiconductor switching element such as a transistor, a thyristor, or a triac, and is connected in series between the fixing heater 51 h and the power supply unit 101. The switch unit 102 is turned on / off under the control of the control unit 103, and phase-controls the heater current flowing from the power supply unit 101 to the fixing heater 51h. The phase control refers to control for gradually increasing the current flowing through the fixing heater 51h when supplying current to the fixing heater 51h. By performing this phase control, it is possible to suppress an inrush current that occurs in the initial stage when supplying current to the fixing heater 51h, and to suppress flicker.

  The zero cross circuit 104 detects the zero cross point of the power supply unit 101 that supplies AC power to the fixing heater 51 h and outputs the detection result to the control unit 103.

  The controller 103 normally shortens the energization time to the fixing heater 51h by setting the time from the zero cross point detected by the zero cross circuit 104 to the heater on longer. Conversely, the control unit 103 sets the time from the zero cross point to the heater ON to be short, thereby extending the energization time to the fixing heater 51h and increasing the amount of heat applied from the fixing heater 51h to the fixing roller 51.

  The rotation drive unit (rotation drive unit) 105 includes, for example, a motor that rotates the rotation shaft of the fixing roller 51, a motor drive circuit that drives the motor, and the like. The rotation driving unit 105 rotates the fixing roller 51 at an appropriate rotation speed by controlling the operation of the motor driving circuit under the control of the control unit 103.

  The thermistor 106 is disposed in the vicinity of the fixing roller 51. For example, a thermistor whose resistance value has a positive characteristic with respect to temperature is used.

  The temperature detection circuit 107 detects the temperature of the fixing roller 51 by detecting the change in the resistance value due to the temperature of the fixing roller 51 of the thermistor 106, that is, the temperature of the fixing heater 51h, and detects the detected temperature signal to the calculation unit 108. Output as. The thermistor 106 and the temperature detection circuit 107 function as a temperature detection unit (temperature detection means) 110 that detects the temperature of the fixing roller 51 as a whole.

  A non-volatile memory such as NVRAM (Non Volatile RAM) is used as the storage unit (information storage unit, storage unit) 109, and a temperature difference detected by the temperature detection unit 110 in each predetermined observation period (hereinafter, as appropriate) Temperature / voltage correspondence information that associates the voltage value of the power supply supplied from the external power supply unit 101 with each other is also stored.

  For example, as shown in FIG. 3, the temperature / voltage correspondence information includes the temperature difference detected by the temperature detection unit 110 in the observation period t2-t1 and the input voltage value (power supply corresponding to the temperature difference in the observation period). This is information (for example, a database) in which the voltage value of power is associated. For example, in FIG. 3, even in the same observation period t2-t1, if the input voltage is 80V, the temperature difference (temperature rise amount) is T2 (80) -T1 (80), and the input voltage is 100V. The temperature difference (temperature rise amount) is T2 (100) -T1 (100), and the input voltage is 120V, the temperature difference (temperature rise amount) is T2 (120) -T1 (120). The storage unit 109 measures in advance these observation periods, temperature difference (temperature rise amount), and input voltage value (voltage value of commercial power supplied to the power supply unit 101), and stores it as initial temperature / voltage correspondence information. Has been.

  Further, the storage unit 109 stores a power supply voltage calculation formula for calculating a voltage value of the power supply power from the detected temperature difference in the observation period. As in the case of obtaining the initial temperature / voltage correspondence information, this power supply voltage calculation formula is obtained in advance by experimentally detecting the detected temperature difference and the power supply voltage value during the observation period, or based on the experimental results or the fixing heater. It is derived from the resistance characteristic of 51h.

  The calculating unit (voltage predicting unit) 108 calculates a detected temperature difference that is an increase amount of the detected temperature during the observation period based on the detected temperature signal from the temperature detecting circuit 107, and based on the calculated detected temperature difference, The input voltage is predicted with reference to the initial temperature / voltage correspondence information. Alternatively, the calculation unit 108 calculates and predicts the input voltage using the power supply voltage calculation formula based on the detected temperature difference in the calculated observation period. Hereinafter, the input voltage predicted by the calculation unit 108 is appropriately referred to as a predicted input voltage. The calculation unit 108 outputs the predicted predicted input voltage to the control unit 103.

  Based on the fixing control program stored in the internal memory or the storage unit 109, the control unit 103 suppresses overshoot with a low-cost and simple configuration when the fixing heater 51h is started up, and the fixing roller 51 as a fixing member. A fixing control process for quickly heating the toner to the target temperature is executed.

  That is, the fixing control unit 100 includes a ROM, an EEPROM (Electrically Erasable and Programmable Read Only Memory), an EPROM, a flash memory, a flexible disk, a CD-ROM (Compact Disc Read Only Memory), a CD-RW (Compact Disc Rewritable), and a DVD. Control by reading a fixing control program for executing the fixing control method of the present invention recorded on a computer-readable recording medium such as (Digital Versatile Disk), SD (Secure Digital) card, MO (Magneto-Optical Disc), etc. By introducing it into the internal memory of the unit 103, the storage unit 109, and the like, a fixing unit that executes a fixing control method for quickly heating the fixing heater 51h to a target temperature while suppressing overshoot with an inexpensive and simple configuration to be described later ( It is constructed as a fixing control unit of the fixing device 50. This fixing control program is a computer-executable program written in a legacy programming language such as assembler, C, C ++, C #, Java (registered trademark), an object-oriented programming language, or the like, and is stored in the recording medium. Can be distributed.

  Then, when the fixing heater 51h is started up, the control unit 103 controls on / off of the switch unit 102 and supplies a current to the fixing heater 51h. Then, the control unit 103 performs heating control of the fixing heater 51h until the detected temperature of the fixing roller 51 indicated by the detected temperature signal from the temperature detecting circuit 107 reaches a target temperature that is a predetermined fixing temperature.

  When the detected temperature exceeds the target temperature, the control unit 103 turns off the switch unit 102 and stops energization of the fixing heater 51h. Thereafter, the control unit 103 controls the switch unit 102 to be turned on / off based on the detected temperature of the fixing roller 51 indicated by the detected temperature signal from the temperature detection circuit 7 so that the fixing roller 51 has a predetermined temperature range. Control to range. In this case, the control unit 103 controls the phase of the current from the power supply unit 101 to the fixing heater 51h by controlling on / off of the switch unit 102 based on the zero-cross detection result of the zero-cross circuit 104. The fixing roller 51 is controlled within a predetermined temperature range. Therefore, the control unit 103 and the switch unit 102 as a whole use the power supply power from the power supply unit 101 that is external power supply supplied from the outside, based on the temperature detected by the temperature detection unit 110, and the fixing heater 51h. It functions as a temperature control means for controlling the temperature of the fixing roller 51 by controlling the power supply to.

  Further, when the temperature of the fixing roller 51 is heated to the fixing roller rotation control start temperature preset in the storage unit 109, the control unit 103 controls the rotation driving unit 105, which is a rotation driving unit, to thereby fix the fixing roller. 51 is rotationally driven at a predetermined rotational speed. The storage unit 109 stores a preset fixing roller rotation control start temperature and stores a preset rotation speed of the fixing roller 51 corresponding to the temperature of the fixing roller 51. As the rotation speed of the fixing roller 51, a higher rotation speed is set as the temperature of the fixing roller 51 is higher. The fixing roller rotation control start temperature is normally set to a temperature lower than the target temperature by a predetermined temperature as shown in FIG. Therefore, the control unit 103 is a rotation control unit that controls the rotation of the fixing roller 51 by the rotation drive unit 105 based on the voltage value predicted by the calculation unit 108 that is a voltage prediction unit and the detected temperature detected by the temperature detection unit 110. It is functioning.

  Next, the operation of this embodiment will be described. In the color image forming apparatus 1 of the present embodiment, the fixing unit 50 quickly heats the fixing roller 51 as a fixing member to a target temperature while suppressing overshoot with an inexpensive and simple configuration.

  In the color image forming apparatus 1, the paper P from the paper feeding unit 10 or the manual paper feeding unit 80 is conveyed between the intermediate transfer belt 61 and the secondary transfer roller 67 of the image forming unit 60 by the paper feeding / conveying unit 20. To do. The image forming unit 60 forms a color toner image by sequentially superimposing the toner images of the respective colors on the intermediate transfer belt 61 by the developing units 62K to 62Y, and at the nip portion between the intermediate transfer belt 61 and the secondary transfer roller 67. Then, it is transferred to the paper P.

  In the color image forming apparatus 1, the paper P on which the toner image is transferred is transported to the fixing unit 50 by the paper discharge transport unit 30 and transported while being heated and pressurized by the fixing unit 50, and the toner image is fixed on the paper P. Then, the paper is discharged onto the paper discharge tray 3.

  When the color image forming apparatus 1 fixes the toner image on the paper P in the fixing unit 50, the color image forming apparatus 1 first starts up the fixing heater 51h that heats the fixing roller 51, and then the predetermined fixing temperature. (Target temperature) is controlled within a predetermined temperature range.

  The fixing control unit 100 performs the starting process of the fixing heater 51h as shown in FIG. That is, when the fixing heater 51h comes up, the fixing control unit 100 turns on the switch unit 102, and starts up the fixing heater 51 that starts energizing the fixing heater 51h (step). S101). This start-up start timing corresponds to time to in FIG.

  Based on the detected temperature signal from the temperature detector 110, the controller 103 waits until the temperature of the fixing heater 51h (fixing roller 51) reaches a preset stable state (step S102). The timing when this stable state is reached corresponds to time t1 in FIG.

  The control unit 103 causes the calculation unit 108 to calculate the temperature difference (temperature rise amount) per observation period (t2-t1 in FIG. 3) when the detected temperature is stabilized. The control unit 103 further causes the calculation unit 108 to predict an input voltage value from the temperature difference (temperature rise amount), and stores the predicted input voltage value and the temperature difference (temperature rise amount) as temperature / voltage correspondence information. 109 (step S104).

  The calculation unit 108 stores the temperature difference (temperature increase amount) per observation period in the storage unit 109, for example, the detected temperature indicated by the detected temperature signal from the temperature detection unit 110 at the timing t1, and then the timing t2. The detected temperature indicated by the detected temperature signal from the temperature detecting unit 110 is stored in the storage unit 109. Then, the calculation unit 108 calculates the temperature difference (temperature rise amount) by subtracting the detected temperature at the timing t1 from the detected temperature at the timing t2.

  Based on the calculated temperature difference (temperature rise amount) and the observation period, the calculation unit 108 is the voltage value of the commercial power supplied to the power supply unit 101, that is, the input voltage supplied to the fixing heater 51h. Predict the value. The calculation unit 108 may predict the input voltage value by calculating the power supply voltage calculation formula stored in the storage unit 109 in advance, or may calculate the initial temperature / value stored in the storage unit 109. The prediction may be performed with reference to the voltage correspondence information. Further, in step S104, the calculation unit 108 stores the predicted input voltage value as temperature / voltage correspondence information in association with the temperature difference (temperature rise amount) and the observation period, thereby predicting the input voltage value from the next time onward. The temperature / voltage correspondence information may be used.

  When the calculation unit 108 predicts the input voltage value, the control unit 103 checks whether the predicted input voltage value is equal to or lower than the rated voltage (100 V) (step S105).

  If the predicted input voltage value is equal to or lower than the rated voltage in step S105 (YES in step S105), control unit 103 reaches the fixing roller rotation control start temperature that is preset and stored in storage unit 109. Wait until. When the temperature detected by the temperature detection unit 110 reaches the fixing roller rotation control start temperature, the control unit 103 rotates the rotation speed of the fixing roller 51 without changing the rotation speed from a preset initial rotation speed. The fixing roller 51 is rotated by the drive unit 105 (step S106).

  The control unit 103 rotates the fixing roller 51, and when the temperature detected by the temperature detection unit 110 falls within a predetermined temperature range centering on the target temperature, or when a predetermined time (for example, 1 second) elapses, the control unit 103 rotates the fixing roller 51h. Startup is completed (step S107).

  If the predicted input voltage value exceeds the rated voltage in step S105 (NO in step S105), the control unit 103 sets the fixing roller rotation control start temperature set in advance and stored in the storage unit 109. Wait until When the temperature detected by the temperature detection unit 110 reaches the fixing roller rotation control start temperature, the control unit 103 changes the rotation speed of the fixing roller 51 from the initial rotation speed at the time of start-up according to the detected temperature, and rotates. The fixing roller 51 is rotated by the drive unit 105 (step S108).

  The control unit 103 rotates the fixing roller 51, and when the temperature detected by the temperature detection unit 110 falls within a predetermined temperature range centered on the target temperature, or when a predetermined time (for example, 1 second) elapses, the fixing heater The start-up of 51h is completed (step S109).

  That is, as shown in FIG. 3, the start-up characteristics of the fixing heater 51h differ depending on the voltage (input voltage) of the input AC commercial power, and the target temperature is set higher as the input voltage is higher than the rated voltage (100V). The overshoot amount to be over increases. Therefore, normally, the higher the input voltage, the longer the stabilization time until the target temperature is stabilized.

  Therefore, in the color image forming apparatus 1 of this embodiment, when the input voltage is equal to or lower than the rated voltage, the fixing is performed at a preset initial rotation speed at the time of startup when the detected temperature rises to the fixing roller rotation start temperature. The roller 51 is rotated. However, if the input voltage exceeds the rated voltage, the fixing roller 51 is rotated at a rotational speed faster than the initial rotational speed at the time of startup when the detected temperature rises to the fixing roller start temperature. By doing so, it is possible to stabilize the fixing roller 51 at the target temperature more quickly while suppressing the amount of overshoot when the input voltage is higher than the rated voltage.

  In the above description, the observation period is set in advance, but can be appropriately set by an operation on the operation display unit of the color image forming apparatus 1. The calculation unit 108 acquires the set observation period via an I / O (period change accepting unit), and inputs the temperature increase amount based on the set observation period under the control of the control unit 103. Predict the voltage.

  Further, the calculation unit 108 predicts an overshoot amount based on the detected temperature from the temperature detection unit 110, stores the predicted overshoot amount in the storage unit 109, and predicts the input voltage in the next and subsequent predictions of the input voltage. An amount of overshoot may be used.

  Then, the control unit 103 may perform a combination of the rotation control of the fixing roller 51 and the energization control to the fixing heater 51 h by the on / off control of the switch unit 102.

  In this way, it is possible to control the fixing roller 51 more quickly to the target temperature while further suppressing overshoot.

  In the above description, the case where the fixing roller 51 is used as the fixing member has been described. However, the fixing member is not limited to the fixing roller 51 and may be an endless belt-like fixing belt or the like. The same can be applied.

  As described above, in the color image forming apparatus 1 of the present embodiment, the fixing unit 50 is heated to the predetermined target temperature by the fixing heater (heating unit) 51h, and the toner image (recording material image) is transferred. A fixing roller (fixing member) 51 that heats a sheet (recording medium) P to fix the toner image on the sheet P, a rotation driving unit (rotation driving means) 105 that rotates the fixing roller 51, and a fixing roller Based on the temperature detection unit (temperature detection means) 110 that detects the temperature of 51 and the temperature detected by the temperature detection unit 110, the power supply to the fixing heater 51h is controlled using external power supplied from the outside. When energization of the control unit 103, the switch unit 102, and the fixing heater 51h as temperature control means for controlling the temperature of the fixing roller 51 is started, the temperature detection unit 110 is detected every predetermined observation period. A calculation unit (voltage prediction unit) 108 that predicts the voltage value of the external power supply power based on the detected temperature to be detected, and a rotational drive based on the voltage value predicted by the calculation unit 108 and the detected temperature detected by the temperature detection unit 110. And a control unit (rotation control means) 103 that controls the rotation of the fixing roller 51 by the unit 105.

  Therefore, the voltage value of the power supply power supplied to the fixing heater 51h is predicted with a simple configuration without using a current detection unit or voltage detection unit for detecting the current value or voltage value of the external power supply power. Then, it is possible to control the rotation of the fixing roller 51 at the time of starting from the start of energization to the fixing heater 51h based on the predicted voltage value. As a result, the fixing roller 51 can be quickly heated to the target temperature with an inexpensive and simple configuration.

  Further, in the color image forming apparatus 1 of this embodiment, the fixing unit 50 is heated to a predetermined target temperature by the fixing heater 51h, and heats the paper P on which the toner image is transferred to the paper P. Based on the rotational drive processing step for rotationally driving the fixing roller 51 for fixing the toner image, the temperature detection processing step for detecting the temperature of the fixing roller 51, and the temperature detected in the temperature detection processing step, the external supply is performed. The temperature control processing step for controlling the temperature of the fixing roller 51 by controlling the power supply to the fixing heater 51h using the external power supply, and the energization to the fixing heater 51h are started every predetermined observation period. A voltage prediction processing step for predicting a voltage value of the external power supply based on the detected temperature detected in the temperature detection processing step; and the voltage prediction processing step. And a rotation control processing step for controlling the rotation of the fixing roller 51 in the rotation drive processing step based on the voltage value predicted in the step and the detected temperature detected in the temperature detection processing step. doing.

  Therefore, the voltage value of the power supply power supplied to the fixing heater 51h is predicted with a simple configuration without using a current detection unit or voltage detection unit for detecting the current value or voltage value of the external power supply power. Then, it is possible to control the rotation of the fixing roller 51 at the time of starting from the start of energization to the fixing heater 51h based on the predicted voltage value. As a result, the fixing roller 51 can be quickly heated to the target temperature with an inexpensive and simple configuration.

  Further, in the color image forming apparatus 1 of the present embodiment, the fixing unit 50 is heated to a predetermined target temperature by a fixing heater 51h by a control processor such as a CPU to heat the paper P on which the toner image is transferred. Then, based on the rotation driving process for rotating the fixing roller 51 for fixing the toner image on the paper P, the temperature detection process for detecting the temperature of the fixing roller 51, and the detected temperature in the temperature detection process, When a temperature control process for controlling the temperature of the fixing roller 51 by controlling the power supply to the fixing heater 51h using the external power supply supplied from the outside and the energization of the fixing heater 51h are started, a predetermined observation period A voltage prediction process for predicting a voltage value of the external power supply power based on a detected temperature detected by the temperature detection process every time, and a voltage value predicted by the voltage prediction process It is equipped with fixing control program for executing a rotation control process for controlling the rotation of the fixing roller 51 in the rotation driving process based on the detection temperature detected by the temperature detection process.

  Therefore, the voltage value of the power supply power supplied to the fixing heater 51h is predicted with a simple configuration without using a current detection unit or voltage detection unit for detecting the current value or voltage value of the external power supply power. Then, it is possible to control the rotation of the fixing roller 51 at the time of starting from the start of energization to the fixing heater 51h based on the predicted voltage value. As a result, the fixing roller 51 can be quickly heated to the target temperature with an inexpensive and simple configuration.

  Further, in the color image forming apparatus 1 according to the present embodiment, when the control unit 103 serving as the rotation control unit exceeds a preset rotation start temperature detected by the temperature detection unit 110, the rotation driving unit 105. The rotation of the fixing roller 51 is started, and the rotation speed of the fixing roller 51 is controlled based on the voltage value predicted by the calculation unit 108.

  Therefore, the rotation of the fixing roller 51 can be more appropriately controlled, and the fixing roller 51 can be heated more quickly to the target temperature while appropriately suppressing the overshoot.

  Further, in the color image forming apparatus 1 according to the present embodiment, the calculation unit 108 performs every observation period after a stable period from the start of energization to the fixing heater 51h until the heating temperature of the fixing heater 51h stabilizes. The voltage value of the external power supply power is predicted.

  Therefore, an accurate voltage value can be predicted, and the fixing roller 51 can be quickly heated to the target temperature while appropriately suppressing overshoot.

  Further, in the color image forming apparatus 1 of the present embodiment, the fixing unit 50 supports the initial temperature and voltage in which the detected temperature detected by the temperature detecting unit 110 and the voltage value of the external power supply are associated with each observation period. The storage unit (information storage unit) 109 that stores information (temperature / voltage correspondence information) is further provided, and the calculation unit 108 determines the initial temperature / temperature based on the detected temperature detected by the temperature detection unit 110 during the observation period. The voltage value of the external power supply power is predicted with reference to the voltage correspondence information.

  Accordingly, a more accurate voltage value can be predicted more quickly, and the fixing roller 51 can be heated more quickly to the target temperature while appropriately suppressing overshoot.

  Further, in the color image forming apparatus 1 of the present embodiment, the calculation unit 108 stores the detected temperature and the predicted voltage value in the observation period as predicted temperature / voltage correspondence information in the storage unit (storage unit) 109. In the prediction of the voltage value after the next time, the voltage value of the external power supply power may be predicted by referring to the predicted temperature / voltage correspondence information in the storage unit 109 based on the detected temperature in the observation period. Good.

  In this way, a more accurate voltage value can be predicted more quickly, and the fixing roller 51 can be heated more quickly to the target temperature while appropriately suppressing overshoot.

  In the color image forming apparatus 1 of the present embodiment, the fixing unit 50 includes a period change receiving unit that receives the change of the observation period, and the calculation unit 108 is based on the observation period received by the period change receiving unit. The voltage value may be predicted. That is, the change of the observation period from the operation display unit or the like of the color image forming apparatus 1 is received by the period change receiving unit such as I / O, and the calculation unit 108 or the control unit 103 stores the changed observation period in the storage unit. 109 and the like, and the calculation unit 108 predicts the input voltage value based on the observation period after the change.

  In this way, it is possible to predict the input voltage value by changing the observation period according to the accuracy required by the user, the installation environment of the color image forming apparatus 1, and the like, and the usability can be improved.

  The invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to that described in the above embodiments, and various modifications can be made without departing from the scope of the invention. It goes without saying that it is possible.

DESCRIPTION OF SYMBOLS 1 Color image forming apparatus 2 Main body housing 3 Paper discharge tray 10 Paper feed part 11 Paper feed tray 12 Paper feed roller 20 Paper feed conveyance part 21 Registration sensor 22 Registration roller 30 Paper discharge conveyance part 31 Paper discharge sensor 32 Paper discharge roller 40 Double-sided conveyance unit 41 Double-sided roller 42 Double-sided sensor 50 Fixing unit 51 Fixing roller 51h Fixing heater 52 Pressure roller 60 Image forming unit 61 Intermediate transfer belt 62K, 62M, 62C, 62Y Developing unit 63 Exposure unit 64 Toner mark sensor 65 Waste toner box 66 Intermediate transfer belt cleaner 67 Secondary transfer roller 68 Secondary transfer drive roller 69 Tension roller 70K, 70M, 70C, 70Y Primary transfer roller 71K, 71M, 71C, 71Y Photoconductor 72K, 72M, 72C, 72Y Charger 73K, 73M, 73C, 73 Y developing unit 74K, 74M, 74C, 74Y cleaning unit 75K, 75M, 75C, 75Y toner storage unit 80 manual sheet feeding unit 81 manual tray 82 manual sheet feeding roller 83 manual bottom plate 90 control board 100 fixing control unit 101 power supply unit 102 Switch unit 103 Control unit 104 Zero cross circuit 105 Rotation drive unit 106 Thermistor 107 Temperature detection circuit 108 Calculation unit 109 Storage unit 110 Temperature detection unit P Paper

JP 2006-39027 A

Claims (9)

A fixing member that is heated to a predetermined target temperature by a heat generating means, heats the recording medium on which the recording material image is transferred, and fixes the recording material image on the recording medium;
A rotation driving means for rotating the fixing member;
Temperature detecting means for detecting the temperature of the fixing member;
Temperature control means for controlling the temperature of the fixing member by controlling power supply to the heat generating means using external power supplied from the outside based on the detected temperature of the temperature detecting means;
When energization to the heat generating means is started, voltage predicting means for predicting the voltage value of the external power supply based on the detected temperature detected by the temperature detecting means for each predetermined observation period;
A rotation control means for controlling rotation of the fixing member by the rotation driving means based on a voltage value predicted by the voltage prediction means and a detected temperature detected by the temperature detection means;
A fixing device. The rotation control means includes
When the detection temperature detected by the temperature detection means exceeds a preset rotation start temperature, the rotation driving means starts rotation of the fixing member and based on the voltage value predicted by the voltage prediction means. The fixing device according to claim 1, wherein a rotation speed of the fixing member is controlled. The voltage predicting means includes
The voltage value of the external power supply is predicted for each observation period after a stable period from the start of energization to the heat generating means until the heating temperature of the heat generating means stabilizes. The fixing device according to claim 2. The fixing device includes:
Information storage means for storing temperature-voltage correspondence information that associates the detected temperature detected by the temperature detection means in each observation period with the voltage value of the external power supply power,
In addition,
The voltage predicting means includes
4. The voltage value of the external power supply is predicted with reference to the temperature / voltage correspondence information based on the detected temperature detected by the temperature detecting means during the observation period. The fixing device according to any one of the above. The voltage predicting means includes
The detected temperature in the observation period and the predicted voltage value are stored in the storage means as predicted temperature / voltage correspondence information, and the voltage value is predicted based on the detected temperature in the observation period in the next and subsequent predictions. 5. The fixing device according to claim 1, wherein the voltage value of the external power supply power is predicted by referring to the predicted temperature / voltage correspondence information stored in a storage unit. The fixing device includes:
Comprising a period change accepting means for accepting a change in the observation period;
The voltage predicting means includes
The fixing device according to claim 1, wherein the voltage value is predicted based on an observation period received by the period change receiving unit. In an image forming apparatus provided with a fixing unit for transferring a recording material image to a recording medium by an image forming means and fixing the recording material image to the recording medium.
An image forming apparatus comprising the fixing device according to claim 1 as the fixing unit. Rotation drive processing step of rotating the fixing member that is heated to a predetermined target temperature by the heat generating means and heats the recording medium on which the recording material image is transferred to fix the recording material image on the recording medium. When,
A temperature detection processing step for detecting the temperature of the fixing member;
A temperature control processing step for controlling the temperature of the fixing member by controlling the power supply to the heat generating means using external power supplied from the outside based on the detected temperature in the temperature detection processing step;
When energization of the heat generating means is started, a voltage prediction processing step for predicting a voltage value of the external power supply power based on the detected temperature detected in the temperature detection processing step for each predetermined observation period;
A rotation control processing step for controlling the rotation of the fixing member in the rotation drive processing step based on the voltage value predicted in the voltage prediction processing step and the detected temperature detected in the temperature detection processing step;
A fixing control method characterized by comprising: To the control processor,
A rotation driving process for rotating and driving a fixing member that is heated to a predetermined target temperature by the heat generating means and heats the recording medium to which the recording material image is transferred to fix the recording material image on the recording medium; ,
Temperature detection processing for detecting the temperature of the fixing member;
A temperature control process for controlling the temperature of the fixing member by controlling the power supply to the heating means using an external power supply supplied from the outside based on the detected temperature in the temperature detection process;
When energization to the heating means is started, a voltage prediction process for predicting a voltage value of the external power supply power based on a detected temperature detected by the temperature detection process for each predetermined observation period;
A rotation control process for controlling the rotation of the fixing member in the rotation driving process based on the voltage value predicted in the voltage prediction process and the detected temperature detected in the temperature detection process;
A fixing control program characterized in that is executed.

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