JP2010066587A - Drive device and image forming apparatus - Google Patents

Drive device and image forming apparatus Download PDF

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JP2010066587A
JP2010066587A JP2008233648A JP2008233648A JP2010066587A JP 2010066587 A JP2010066587 A JP 2010066587A JP 2008233648 A JP2008233648 A JP 2008233648A JP 2008233648 A JP2008233648 A JP 2008233648A JP 2010066587 A JP2010066587 A JP 2010066587A
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drive
transfer
driven
unit
target value
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JP5117332B2 (en
Inventor
Toshiyuki Ando
Takashi Hashimoto
Takashi Hodoshima
Seiji Hoshino
Eigo Noguchi
Tatsuhiko Oikawa
達彦 及川
俊幸 安藤
誠治 星野
崇 橋本
隆 程島
英剛 野口
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Ricoh Co Ltd
株式会社リコー
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Abstract

A drive device and an image forming apparatus capable of calculating a feedforward target value capable of appropriately suppressing a speed fluctuation of a driven portion by feedforward control.
A drive source, a driven unit, a drive transmission unit that transmits drive from the drive source to the driven unit, a drive information acquisition unit that acquires driven information of the driven unit, and the driven information are used. A feedback control unit that performs drive control of the driving source, a feedforward control unit that performs feedforward control using a feedforward target value with respect to drive fluctuations of the driven part, and fluctuation prediction that predicts the occurrence timing of the drive fluctuations When the feedback control unit has a plurality of control gains, the control gain is switched to a lower gain than during normal operation, and the apparatus main body is operated without performing the feedforward control. Target value calculating means for calculating a feedforward target value using the driven information acquired in step (b).
[Selection] Figure 1

Description

  The present invention relates to a driving device used in an image forming apparatus such as a printer, a facsimile machine, and a copying machine, and an image forming apparatus using the driving device.

In recent years, in a color image forming apparatus, a toner image on a photosensitive member is primarily transferred onto an intermediate transfer member such as an intermediate transfer drum or an intermediate transfer belt at a primary transfer portion, and four color toner images on the intermediate transfer member are obtained. An intermediate transfer method in which secondary transfer is performed on the transfer paper at the secondary transfer portion is often employed. In the image forming apparatus using the intermediate transfer member, various types of sheet-like members such as thin paper, thick paper, postcard, and envelope can be used, and there is an advantage that versatility is high.
However, when a sheet-like member having a thickness of a certain level or more enters the secondary transfer portion, the speed of the intermediate transfer member that has been driven at a constant speed fluctuates for a short time until the primary transfer portion. There was a problem that the image was disturbed.

  In addition, as the color image forming apparatus is miniaturized, there is also an apparatus in which the secondary transfer unit and the fixing unit are brought close to each other, and image transfer and fixing are simultaneously performed on a sheet-like member. Even in this apparatus, when a sheet-like member having a thickness of a certain level or more enters the fixing unit, the speed of the fixing roller or the fixing belt that has been driven at a constant speed fluctuates for a short time, and the secondary member There has been a problem that the image is disturbed at the transfer portion.

  In addition, there is an image forming apparatus having a transfer fixing device that simultaneously performs image transfer and image fixing when transferring a toner image to a sheet-like member in order to improve image quality. Also in this case, when a sheet-like member having a thickness of a certain level or more enters the transfer fixing unit, the speed of the intermediate transfer member that has been driven at a constant speed decreases until a short time. There may be a problem that the image is disturbed in the secondary transfer portion.

  Regarding the speed fluctuation of the intermediate transfer body, etc. whose speed increases or decreases in a certain period of time, while detecting the speed fluctuation of the intermediate transfer body, the result is fed back to the driving speed of the drive motor that drives the intermediate transfer body. By performing feedback control, the speed of the intermediate transfer member can be stabilized. However, it is difficult for the above-described feedback control to cope with the sudden speed fluctuation of the intermediate transfer member due to the sudden load fluctuation that occurs when the sheet-like member enters the secondary transfer portion or the like.

  The above problem is that when the sheet-like member enters the secondary transfer unit, the fixing unit, or the transfer fixing unit, the timing at which the speed fluctuation occurs in the intermediate transfer member due to the entry is predicted. It can be avoided by feed-forward control that cancels the speed fluctuation by increasing the speed of the intermediate transfer member (Patent Document 1 and Patent Document 2). Prediction of the timing at which the speed fluctuation occurs can be performed by using a sheet-like member detection sensor installed immediately before the fixing unit as in the image forming apparatus described in Patent Document 3, for example. In other words, the time from when the sheet-like member detection sensor detects the sheet-like member until the sheet-like member enters the fixing unit is measured in advance, and the measured time is detected based on the detection of the sheet-like member. It is used as the timing when

  FIG. 25 shows a conceptual diagram of feedforward control. The speed fluctuation Va can be represented by a speed component waveform in a predetermined period as shown in FIG. For example, as the feedforward control when the speed fluctuation Va occurs in the intermediate transfer member, the intermediate transfer is performed at a speed Vb that is a feedforward target value that cancels the speed fluctuation Va as shown in FIG. 25A when the speed fluctuation Va occurs. Control the body to drive. As a result, the speed fluctuation Va can be canceled as shown in FIG. 25B, and the intermediate transfer member can be driven at a constant speed.

  FIG. 26 shows a conceptual diagram of conversion from a speed fluctuation to a feedforward target value in a driven part such as an intermediate transfer member. The feedforward target value is obtained by subtracting the speed fluctuation portion from the measurement data of the speed fluctuation by subtracting the steady speed Vs of the driven part as an offset amount and inverting the sign.

  Usually, the feedforward control as described above is often used in combination with the feedback control. In the image forming apparatus described in Patent Document 4, the predicted timing at which the predicted sheet-like member enters the transfer nip while stably driving the drive roller, which is one of the roller pair forming the transfer nip, by feedback control. Thus, feedforward control is performed using a feedforward target value that cancels the speed fluctuation of the driving roller.

  In the image forming apparatus described in Patent Document 4, feedforward target values corresponding to several types of sheet-like members are stored in advance in the storage unit of the apparatus body, but the thickness is not stored in advance. The feedforward target value corresponding to the sheet-like member can be calculated and added and stored. The feed-forward target value to be added is sent through a sheet-like member having a thickness to be added to the image forming apparatus in a mode set so that feed-forward control is not performed, and the sheet-like member enters the transfer nip. The speed fluctuation information of the driving roller at the time is acquired and calculated from the speed fluctuation information. Then, the calculated feedforward target value is stored in the storage unit of the apparatus main body. As described above, the feed-forward target value of the sheet-like member having a thickness not previously stored in the apparatus main body can be appropriately calculated and stored in the apparatus main body, so that the sheet-like member having various thicknesses can be stored. On the other hand, optimal feedforward control can be performed.

JP-A-2005-107118 JP 2003-215870 A JP 2004-54120 A JP 2008-94573 A

  However, in the above mode, although feedback feed control is not performed, feedback control is performed. The following problems may occur if feedback control is performed on the driven part when acquiring speed fluctuation information of the driven part such as a driving roller used to calculate the feedforward target value. .

  FIG. 27 shows a case where two sheet-like members are used when neither the feedback control nor the feed-forward control is performed when acquiring the speed fluctuation information of the intermediate transfer member that is the driven unit in the image forming apparatus. FIG. 6 shows the speed fluctuation of the intermediate transfer member generated by entering the next transfer portion. As shown in FIG. 27, a speed fluctuation 1 occurs in the vicinity of 0.38 [s], and a speed fluctuation 2 occurs in the vicinity of 0.4 [s] immediately after the speed fluctuation 1 occurs.

  Therefore, in the case where neither the feedback control nor the feedforward control is performed when acquiring the speed fluctuation information of the intermediate transfer member that is the driven unit in the image forming apparatus, as shown in FIG. A feedforward target value that cancels each of the speed fluctuation 1 and the speed fluctuation 2 is calculated from the speed fluctuation information.

  FIG. 28 illustrates an intermediate transfer member that is generated when a sheet-like member enters the secondary transfer unit when feedback control is performed and feedforward control is not performed when the speed fluctuation of the intermediate transfer member is acquired in the image forming apparatus. It shows the speed fluctuation. As shown in FIG. 28, even in this case, the speed fluctuation 1 occurs in the vicinity of 0.38 [s], but occurs in the vicinity of 0.4 [s] immediately after the speed fluctuation 1 that occurred in FIG. The speed fluctuation 2 that has been generated does not occur. When trying to suppress the speed fluctuation 1 by the feedback control, the feedback control is performed after the speed fluctuation 1 occurs, so that the effect of the control starts to be delayed. For this reason, it is considered that the speed fluctuation 2 that occurred immediately after the speed fluctuation 1 in FIG. 27 is suppressed by the feedback control performed to suppress the speed fluctuation 1.

  Therefore, when acquiring the speed fluctuation information of the intermediate transfer member in the image forming apparatus, when the feedback control is performed and the Ford forward control is not performed, the speed fluctuation 1 is canceled out from the speed fluctuation information as shown in FIG. A correct feedforward target value is calculated. When the feedforward control using the feedforward target value calculated in this way is combined with the feedback control, the speed fluctuation of the intermediate transfer member caused by the sheet-like member entering the secondary transfer portion Is shown in FIG.

As shown in FIG. 29, it can be understood that the speed fluctuation 1 generated in FIG. 28 is suppressed by performing the feedforward control using the calculated feedforward target value at the timing when the speed fluctuation 1 occurs. . However, the speed fluctuation 2 that has been suppressed by the feedback control in FIG. 28 is newly generated. In FIG. 29, the speed fluctuation 1 is suppressed by the feedforward control, and the feedback control for the speed fluctuation 1 as performed in FIG. 28 is not performed. For this reason, the speed fluctuation 2 suppressed by the feedback control with respect to the speed fluctuation 1 in FIG. 28 occurs.
The feedforward control for suppressing the speed fluctuation 2 may be performed so that the speed fluctuation 2 does not occur. However, the feedforward target value corresponding to the speed fluctuation 2 is not calculated from the speed fluctuation information as shown in FIG. For this reason, in FIG. 29, feedforward control that suppresses the speed fluctuation 2 cannot be performed.

  As described above, when the feedforward target value calculated from the speed fluctuation information of the driven part such as the intermediate transfer member acquired while performing the feedback control cannot properly suppress the speed fluctuation of the driven part by the feedforward control. There is.

  If neither the feedback control nor the feedforward control is performed when acquiring the speed fluctuation information of the driven part in the image forming apparatus, the feedforward target value as shown in FIG. 27 is calculated. Appropriate speed fluctuation information can be obtained. However, when feedback control is not performed, the speed of the driven part may become unstable. As described above, the feedforward target value is obtained by subtracting the speed fluctuation portion from the measurement data of the speed fluctuation by subtracting the steady speed of the driven part as an offset amount and reversing the sign. Therefore, if the steady speed is greatly different between when the feedback control is performed and when the feedback control is not performed, there is a possibility that an appropriate feedforward target value cannot be calculated.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a drive device that can calculate a feedforward target value that can appropriately suppress the speed fluctuation of the driven portion by feedforward control, and the drive device. An image forming apparatus is provided.

In order to achieve the above object, the invention of claim 1 includes a drive source, a driven unit driven by the drive source, a drive transmission unit that transmits drive from the drive source to the driven unit, Drive information acquisition means for acquiring driven information of the driven part, a feedback control part for performing drive control of the drive source using the driven information acquired by the drive information acquisition means, and the driven part A feed-forward control unit that performs feed-forward control using a feed-forward target value that cancels out the driving fluctuation with respect to the non-periodic driving fluctuation; and a fluctuation prediction unit that predicts the timing of occurrence of the non-periodic driving fluctuation; The feedback control unit has a plurality of control gains, the control gain is switched to a lower gain than in normal operation, and the feedforward Target value calculating means for calculating the feedforward target value using the driven information acquired by the drive information acquiring means when the apparatus main body is operated without performing feedforward control by the control unit. It is characterized by comprising.
According to a second aspect of the present invention, there is provided a drive source, a driven part driven by the drive source, a drive transmission part for transmitting drive from the drive source to the driven part, and the driven part of the driven part A first drive information acquisition unit that detects information, a feedback control unit that performs drive control of the drive source using the driven information acquired by the first drive information acquisition unit, and the driven unit A feed-forward control unit that performs feed-forward control using a feed-forward target value that cancels the non-periodic drive fluctuation, and a fluctuation prediction unit that predicts the timing of occurrence of the non-periodic drive fluctuation; The drive device has a second drive information acquisition unit that acquires drive information of the drive source, and the feedback control unit uses the drive information acquired by the second drive information acquisition unit. The driven information acquired by the first driving information acquisition means when the apparatus main body is operated without performing the feedforward control by the feedforward control unit. And a target value calculation means for calculating the feedforward target value.
According to a third aspect of the present invention, in the driving device of the second aspect, the position resolution of the first drive information acquisition means in terms of the driven part and the position of the second drive information acquisition means in terms of the driven part. The resolution is equal.
According to a fourth aspect of the present invention, in the drive device according to the second aspect, the drive source is driven and controlled by a PLL system, and the position resolution of the first drive information acquisition means is the second drive information acquisition. It is a product of the position resolution of the means and the reduction ratio of the drive transmission unit.
According to a fifth aspect of the present invention, there is provided a latent image carrier that carries a latent image, developing means for developing the latent image on the latent image carrier into a toner image, and a toner image on the latent image carrier. Intermediate transfer means for transferring to the intermediate transfer member, secondary transfer means for transferring the toner image transferred to the intermediate transfer member to the sheet-like member, and fixing the toner image transferred to the sheet-like member to the sheet-like member An image forming apparatus including a fixing unit to be used is characterized in that the driving device according to claim 1, 2, 3, or 4 is used as at least one driving unit of the intermediate transfer unit and the fixing unit. .
According to a sixth aspect of the present invention, there is provided a latent image carrier that carries a latent image, a developing unit that develops the latent image on the latent image carrier into a toner image, and a toner image on the latent image carrier. In an image forming apparatus comprising an intermediate transfer unit for transferring to an intermediate transfer member and a transfer fixing unit for transferring and fixing a toner image transferred to the intermediate transfer member to a sheet-like member, as a drive unit for the intermediate transfer unit The drive device of claim 1, 2, 3 or 4 is used.
According to a seventh aspect of the present invention, there is provided a latent image carrier that carries a latent image, developing means that develops the latent image on the latent image carrier into a toner image, and a toner image on the latent image carrier. Intermediate transfer means for transferring to the intermediate transfer member, secondary transfer means for transferring the toner image transferred to the intermediate transfer member to the second intermediate transfer member, and the toner image transferred to the second transfer member. 5. The driving device according to claim 1, wherein at least one of the intermediate transfer unit and the secondary transfer unit is used as a driving unit in the image forming apparatus including a transfer fixing unit that transfers and fixes the sheet-like member. It is characterized by using.
According to an eighth aspect of the present invention, in the image forming apparatus according to the fifth, sixth or seventh aspect, the image forming apparatus has a target value calculation mode for calculating the feedforward target value.

In the first aspect of the invention, when the driven information used by the target value calculation means for calculating the feedforward target value is acquired by the drive information acquisition means, the feedforward control is not performed and the control gain of the feedback control is set. Lower than normal operation. As a result, the effect of suppressing the drive fluctuation of the driven part by the feedback control is reduced as compared with the case where the feedback control is performed using the control gain during the normal operation, and the drive fluctuation becomes noticeable as the effect is reduced. . Therefore, the feed-forward target value is calculated by the target value calculation means using the driven information acquired by the drive information acquisition means and in which the drive fluctuation becomes significant. Therefore, it is possible to calculate a feedforward target value that can appropriately suppress the drive fluctuation by feedforward control.
According to the second aspect of the present invention, the feedforward control is not performed when the first drive information acquisition unit acquires the driven information of the driven unit used when the target value calculation unit calculates the feedforward target value. Further, feedback control is performed so as to suppress drive fluctuations of the drive source using the drive information of the drive source. As a result, it is possible to suppress the drive fluctuation of the driven part by the feedback control, compared to the case of performing feedback control that controls the drive part using the driven information of the driven part and suppresses the drive fluctuation of the driven part. As the effect is reduced, the drive fluctuation of the driven part becomes remarkable. Accordingly, the feedforward target value is calculated by the target value calculation means using the driven information acquired by the first driving information acquisition means and in which the drive fluctuation of the driven part becomes significant. Therefore, it is possible to calculate a feedforward target value that can appropriately suppress the drive fluctuation by feedforward control.

  As mentioned above, according to this invention, there exists the outstanding effect that the feedforward target value which can suppress appropriately the speed fluctuation of a to-be-driven part by feedforward control can be calculated.

[Embodiment 1]
Hereinafter, a first embodiment of a drive device to which the present invention is applied will be described. In the present embodiment, the feedback control gain is switched when calculating the feedforward target value.

  FIG. 2 is a diagram showing an example of a drive device to which the present invention is applied. The drive source 1 and the driven part 2 are connected by a drive transmission part composed of a small diameter gear 3 and a large diameter gear 4, and drive information acquisition means 5 for acquiring driven information of the driven part 2 is connected to the driven part 2. is set up. As the drive source 1, a brushless DC motor, a pulse motor, an ultrasonic motor, a direct drive motor, or the like can be used. The drive transmission unit may use a transmission mechanism such as a gear and a toothed belt, a pulley and a V belt, or a planetary gear in addition to the gear transmission mechanism including the small diameter gear 3 and the large diameter gear 4 as described above. good. Further, when an ultrasonic motor or a direct drive motor is used as the drive source 1, the driven part 2 can be driven directly without using a drive transmission part due to the characteristics of the motor.

  The feedback control unit 6 uses the driven information of the driven unit 2 acquired by the driving information acquisition unit 5 so that the driven unit 2 is driven according to a target value such as a preset speed. Is controlling. As the drive information acquisition means 5, a rotary encoder, a linear encoder, a laser Doppler meter, or the like can be used. When an ultrasonic motor or a direct drive motor is used as the drive source 1, open loop control is possible without performing feedback control due to the characteristics of the motor.

  The feedforward control unit 7 performs feedforward control on aperiodic drive fluctuations that occur in the driven part 2 and corrects the aperiodic drive fluctuations.

  FIG. 25 shows a conceptual diagram of the feedforward control. In the feedforward control, the driven part 2 is driven at the speed Vb so as to cancel the speed fluctuation with respect to the speed fluctuation Va that is an aperiodic (impact) driving fluctuation generated in the driven part 2. By performing the control in this way, it is possible to cancel the speed fluctuation that is the driving fluctuation of the driven unit 2 and drive at a constant speed.

  The fluctuation prediction means 8 is a means for predicting the occurrence of non-periodic drive fluctuations that occur in the driven section 2 and outputs a prediction signal to the feedforward control section 7 when the occurrence of non-periodic drive fluctuations is predicted. To do. Receiving this signal, the feedforward control unit 7 outputs a feedforward target value stored in advance at a predetermined timing, and controls the driving of the driving source 1 to suppress non-periodic speed fluctuations. Here, the predetermined timing is the time from when the fluctuation prediction means 8 predicts that a non-periodic drive fluctuation occurs until the actual fluctuation occurs, which is also stored in the feedforward control unit 7 in advance. ing. The target value calculation means 9 calculates a feedforward target value used in feedforward control.

  FIG. 26 shows a conceptual diagram of the conversion from the speed fluctuation to the feedforward target value in the driven unit 2. The feedforward target value is obtained by subtracting the steady speed Vs of the driven unit 2 serving as an offset amount from the speed fluctuation measurement data, inverting the positive and negative, and cutting out only the speed fluctuation portion. In addition, when the fluctuation amount of the speed fluctuation in the driven unit 2 varies, the average value of the speed fluctuations for a plurality of times is converted into the feedforward target value, so that a stable feedforward control effect can be obtained even when the fluctuation occurs. It is possible to obtain Then, the feedforward target value obtained in this way is stored in a storage unit provided in the feedforward control unit 7. The details of the method for calculating the feedforward target value by the target value calculating means 9 will be described later.

  Here, the driven part 2 may have a configuration including not only the roller as shown in FIG. 2 but also the endless belt 14 as shown in FIG. In this case, the driven portion 2 includes a driving roller 10, support rollers 11, 12, and 13 and an endless belt 14. In FIG. 3, the drive information acquisition unit 5 is installed on the support roller 11 in order to control the endless belt 14. . In this example, the driven information of the endless belt 14 is acquired indirectly from the support roller 11, but the speed fluctuation of the endless belt 14 is directly acquired using a laser Doppler meter, a linear encoder, or the like. May be. Further, the number and position of the support rollers are not limited to the configuration shown in FIG. 3, and any configuration may be used.

  Next, factors that cause non-periodic drive fluctuations in the driven unit 2 will be described with some examples. For example, as shown in FIG. 4, there are a sliding member 41 that can be brought into and out of contact with the driven part 2 and an actuator 42 that drives the sliding member 41, and the sliding member 41 is with respect to the driven part 2. When contact / separation is performed at the timing, a load fluctuation occurs in the driven unit 2 as the sliding member 41 contacts / separates, and as a result, a non-periodic drive fluctuation occurs in the driven unit 2.

  Further, as shown in FIG. 5, the pressing member 43 is pressed against the driven portion 2 by a tension member 44 such as a spring, and the pressure applied to the pressing member 43 by the actuator 45 is given at a certain timing. In the case of changing, a load fluctuation occurs in the driven unit 2 with the change in the applied pressure, and as a result, a non-periodic driving fluctuation occurs in the driven unit 2.

  Further, as shown in FIG. 6, the pressing member 46 is pressed against the driven part 2 by a tension member 47 such as a spring, and the transport roller 51 is brought into contact with the pressing part between the driven part 2 and the pressing member 46. , 52, when the sheet-like member 48 is invaded, load fluctuation occurs in the driven part 2 when the sheet-like member 48 enters, and as a result, non-periodic driving fluctuation occurs in the driven part 2. .

  The same applies to the case where the driven portion 2 as shown in FIGS. 7, 8, and 9 includes the roller members 53 and 54 and the endless belt 30 stretched around these roller members. A load fluctuation of the driven unit 2 occurs, and as a result, a non-periodic driving fluctuation occurs in the driven unit 2.

  Here, the fluctuation prediction means 8 will be described with reference to the examples of FIGS. 4, 5, 6, 7, 8, and 9. In the examples of FIGS. 4, 5, 7, and 8, the fluctuation prediction means 8 may detect a drive start command signal for the actuators 42 and 45 and output a fluctuation prediction signal to the feedforward controller 7 after the detection. . In addition, the actuator drive start command signal or the like may be directly guided to the feedforward control unit or the like without using the CPU or the like to constitute the fluctuation prediction means 8.

  In the example of FIGS. 6 and 9, the fluctuation predicting means 8 functions as a sheet-like member detecting means for detecting the sheet-like member 48, and the fluctuation is detected when the sheet-like member 48 is detected by the fluctuation predicting means 8. What is necessary is just to output a prediction signal to the feedforward control part 7 grade | etc.,.

  Alternatively, a method may be used in which signals such as driving start signals for the conveying rollers 51 and 52 that convey the sheet-like member 48 are acquired and a fluctuation prediction signal is output to the feedforward control unit 7. In this case, a drive start signal or the like may be directly guided to the feedforward control unit 7.

  Next, details of the control unit of the drive device according to the present embodiment will be described with reference to FIG. This control unit includes a feedback control unit 6, a feedforward control unit 7, and target value calculation means 9. However, FIG. 1 is an example of the configuration of the control unit, and the control unit is not limited to this configuration.

  In a normal driving state, the feedback control unit 6 and the feedforward control unit 7 function. The feedback control unit 6 calculates the difference between the driven information of the driven unit 2 obtained by the driving information acquisition means 5 and the target value, and the drive command value for the driving source 1 so that this difference is always minimized. Is output. In this embodiment, there are a plurality of feedback control gains used for feedback control. In the example shown in FIG. 1, the feedback control unit 6 has two feedback control gains of a feedback gain 60 and a feedback gain 61. Yes. In the normal state, feedback control for suppressing the drive fluctuation of the driven unit 2 is performed by the feedback control unit 6 using the optimized feedback gain 60.

  The feedforward control unit 7 receives the fluctuation prediction signal from the fluctuation prediction unit 8 and outputs the feedforward target value stored in the storage unit 71 at a predetermined timing stored in the storage unit 71. The output feedforward target value is added to the drive command value output from the feedback control unit 6 to generate a corrected drive command value. Such control is performed in the normal state.

  On the other hand, in the target value calculation state in which the feedforward control target value is calculated, the feedback control unit 6 and the target value calculation unit 9 function. In the target value calculation state for calculating the feedforward target value, the feedback gain 60 used in the normal state is switched to the feedback gain 61 used in the target value calculation state.

  As described above in “Problems to be Solved by the Invention”, when feedback control and feedforward control are used together in order to suppress speed fluctuations of the driven unit 2, the feed is controlled by the influence of the feedback control. The forward control target value cannot be determined appropriately, and there may arise a problem that the optimum feedforward control effect cannot be obtained.

  FIG. 10 shows the speed fluctuation of the driven part 2 (intermediate transfer member) when the feedforward control and the feedback control are used in combination to suppress the speed fluctuation 1 and the speed fluctuation 2 shown in FIG. Is shown. If the feedforward control that cancels the speed fluctuation 1 and the speed fluctuation 2 is applied, the speed fluctuation 1 and the speed fluctuation 2 can be achieved by the combined use of the feedback control and the feedforward control without causing the problem shown in FIG. Can be suppressed.

  That is, in a state where the feedback control gain in the target value calculation state is reduced below the optimum value of the feedback control gain used in the normal state and the influence of the feedback control is small, that is, in the state where the speed fluctuation of the driven unit 2 becomes significant. Drive information of the driven unit 2 is acquired by the drive information acquisition means 5, and a feedforward target value is calculated using the acquired drive information. In the normal state, by using both feedforward control using the feedforward target value and feedback control, the speed fluctuation of the driven unit 2 (intermediate transfer member) can be effectively reduced as shown in FIG. It becomes possible to suppress.

  Thus, when calculating the feedforward control target value, it is necessary to reduce the feedback control gain, and therefore the feedback gain 61 is set to a value lower than the feedback gain 60.

  When the feedback control unit 6 is designed as an analog system, a circuit corresponding to the feedback gain 60 and a circuit corresponding to the feedback gain 61 are respectively designed as shown in FIG. Do. The switch 62 may be either mechanical or electronic. Further, when the feedback control unit 6 is designed in a digital system, a numerical value corresponding to the feedback gain 60 and a numerical value corresponding to the feedback gain 61 are respectively held, and calculation is performed by switching these numerical values. Good.

  In a state where the feedback control gain is lowered, the aperiodic drive fluctuation information generated in the driven section 2 is acquired by the drive information acquisition means 5, and the obtained drive fluctuation information and the target value stored in advance in the storage section 91 are acquired. The feedforward target value is calculated by the target value calculation means 9 using the calculation formula. In the target value calculation formula, for example, an inverse function of a transfer function from the driving source 1 to the fluctuation information obtained by the driving information acquisition unit 5 may be identified in advance and stored in the storage unit 91. The feedforward target value calculated by the target value calculation means 9 is stored in the storage unit 71 of the feedforward control unit 7 and is output when the feedforward control is executed. Further, the target value calculating means 9 can also calculate the predetermined timing for executing the feedforward control.

  The calculation of the feedforward target value and the predetermined timing will be described in more detail with reference to FIG. In FIG. 11, the upper stage is the output of the fluctuation prediction means 8, and the lower stage is the speed fluctuation of the driven unit 2 obtained by the drive information acquisition means 5. Here, speed variation is shown as an example of driven information. In FIG. 11, Ta is the time when the fluctuation predicting means 8 predicts the load fluctuation to the driven part 2, Tb is the time when the speed fluctuation occurs in the driven part 2, and Tc is the speed fluctuation in the driven part 2 is terminated. It's time.

  When the feedforward target value and the predetermined timing are calculated, the calculation process is started from time Ta. First, the time Tb−Ta is measured, and the measured time is stored in the storage unit 91 of the target value calculation means 9 as the predetermined timing which is a timing time for executing the feedforward control. Here, Tb may be determined by determining that the speed variation has occurred in the driven unit 2 when the driven information exceeds a preset threshold, and obtaining the time at that time. Next, the feed-forward target value may be calculated by calculating using the driven information during the period from Tb to Tc and the target value calculation formula stored in the storage unit 91.

  Further, the feedforward target value may be calculated by calculating the driven information during the period from Ta to Tc and the target value calculation formula stored in the storage unit 91. In this case, since the calculated feedforward target value also covers the time portion of Tb-Ta, it is not necessary to store Tb-Ta as the timing time of feedforward control.

  The calculated feedforward target value is stored in the storage unit 71 of the feedforward control unit 7. Regarding the storage of the calculated feedforward target value, it may be once stored in the storage unit 91 of the target value calculation means 9 and then transferred to the storage unit 71, and the method is not particularly limited.

  When the calculation of the feedforward target value by the target value calculation means 9 is completed, the feedback control gain of the feedback control unit 6 is returned from the feedback gain 61 used in the target value calculation state to the feedback gain 60 used in the normal state. In a normal state, feedforward control using the calculated feedforward target value and feedback control may be used in combination.

  Further, there is a possibility that an operation of returning the feedback control gain from the feedback gain 61 used in the target value calculation state to the feedback gain 60 used in the normal state may be forgotten. If the above operation is forgotten, the feedback control gain in the normal state cannot be sufficiently obtained because the feedback control gain is low. Therefore, a command signal is output at the end of feed-forward target value calculation speed fluctuation information acquisition, at the end of the feed-forward target value calculation operation, or at the end of storage of the feed-forward target value in the storage unit 71, etc. It is preferable to provide a function of switching the switch 62 of the feedback control unit 6 back to the feedback gain 60 automatically.

  As described above, in the present embodiment, when the drive information acquisition unit 5 acquires the driven information used when the target value calculation unit 9 calculates the feedforward target value, the feedback control gain is temporarily set to be higher than that at the normal time. A method of calculating the feedforward target value by decreasing the value and returning the feedback control gain to the normal state when the target value calculation is completed was shown. During normal operation, the feedforward control using the feedforward target value calculated in this manner can effectively suppress drive fluctuations that occur in the driven unit 2.

[Embodiment 2]
Hereinafter, a second embodiment of the drive device to which the present invention is applied will be described. In the present embodiment, the signal fed back when calculating the feedforward target value is switched from the speed information of the driven unit 2 to the speed information of the driving source 1.

  FIG. 12 shows an example of the speed fluctuation of the intermediate transfer body when the speed information of the drive source of the intermediate transfer body is fed back and the drive source is controlled so that the drive speed of the drive source approaches the target value. In FIG. 12, since the feedback control is performed on the drive source using the speed information of the drive source, the intermediate transfer member is more subjected to the feedback control on the drive source using the speed information of the intermediate transfer member. The effect of suppressing the generated speed fluctuation is small. Therefore, as shown in FIG. 12, the speed fluctuation 1 and the speed fluctuation 2 remain without being suppressed by the feedback control.

  That is, only when calculating the feedforward control target value, the feedback signal is switched from the speed information of the driven unit 2 (intermediate transfer member) to the speed information of the driving source 1 to calculate the feedforward target value. By using both the feedforward control using the feedforward target value and the feedback control, the speed fluctuation of the driven unit 2 (intermediate transfer member) can be reduced without causing a problem as in the case of the first embodiment. It can be effectively suppressed.

  An example of this embodiment is shown in FIGS. 2 and 3 of the first embodiment is that the drive information of the drive source 1 can be fed back. In FIG. 13, drive information acquisition means 15 for acquiring drive information of the drive source 1 is installed, and the drive information of the drive source 1 is fed back to the feedback control unit 6. Some drive sources have a function of outputting a drive signal corresponding to the rotational speed, and if they are used, as shown in FIG. 14, drive information acquisition means for acquiring drive information of the drive source 1 is separately installed. There is no need to do.

  Details of the control unit of the drive device according to the present embodiment will be described with reference to FIG. Basically, it is the same as the control unit described in Embodiment 1 with reference to FIG. The differences are that the feedback control unit 6 has a single feedback control gain, the switch 63 can switch drive information used for feedback control, and the switch 64 can switch the feedback target value. Etc. Further, the switch 63 and the switch 64 are configured to operate in conjunction with each other. The switches 63 and 64 may be either mechanical or electronic. Further, the switch 63 may be inside the feedback control unit 6 or may be installed outside the feedback control unit 6.

  In a normal state, the signal from the drive information acquisition means 5 is fed back, and the drive source 1 is controlled so that the driven part 2 is driven according to the target value 1. On the other hand, in the target value calculation state in which the feedforward target value is calculated, the switch 63 and the switch 64 are switched so that the drive information of the drive source 1 is fed back, and the drive source 1 is driven and controlled according to the target value 2. .

  Here, the position resolution in terms of the surface position of the driven part 2 of the drive information acquisition means 5 and the position resolution in terms of the surface position of the driven part 2 of the drive information acquisition means 15 are configured to be equal. It is good to keep. With this configuration, since the signals output from the drive information acquisition unit 5 and the drive information acquisition unit 15 are equal, the configuration of the feedback control system can be simplified.

  When the drive source 1 is controlled by a PLL (Phase Locked Loop) method, the clock frequency (F1 Hz) obtained by the drive information acquisition unit 5 and the clock frequency (F2 Hz) obtained by the drive information acquisition unit 15 It is preferable to adjust the position resolution of the drive information acquisition means 5 and the drive information acquisition means 15 so that the two are equal (F1 = F2).

  For example, when the reduction ratio (N3) in the drive transmission unit is 10, the position resolution (N1ppr) of the drive information acquisition unit 5 may be set to 10 times the position resolution (N2ppr) of the drive information acquisition unit 15. Thus, if the position resolution and the reduction ratio of the drive information acquisition means 5 and the drive information acquisition means 15 are set so as to satisfy N1 = N2 × N3, the feedback target value is set as shown in FIG. There is no need to set a plurality of settings, and the switch 64 is not necessary. Thereby, simplification of the feedback control unit 6 and further simplification of the entire control unit can be achieved.

  Further, when there is a limit in the setting of the position resolution between the drive information acquisition means 5 and the drive information acquisition means 15, the drive information is used by using a frequency divider or a multiplier so that the relationship of F1 = F2 is established. The frequency of the clock signal obtained from the obtaining unit 5 or the drive information obtaining unit 15 may be electrically adjusted.

  When the target value calculation is completed, the switch 63 and the switch 64 are switched again to return to the original control state, that is, the normal state. By using such a method, it is possible to temporarily reduce the feedback control effect on the driven unit 2 when calculating the target value, and is similar to the method of temporarily reducing the feedback control gain of the first embodiment. The effect is obtained. Other configurations, various control methods, and a method for calculating the feedforward target value are the same as those in the first embodiment, and thus details thereof are omitted.

  In addition, since there is a possibility that the operation to return to the normal feedback control state may be forgotten, the target value calculation speed variation information acquisition end, the target value calculation operation end, or the target value storage unit 71 It is preferable to provide a function of outputting a command signal at the end of storage, switching the switches 63 and 64 according to the signal, and automatically returning the feedback signal to the original state.

  In addition, since there is a possibility that the operation to return to the normal feedback control state may be forgotten, the feedforward target value calculation speed fluctuation information acquisition end, the feedforward target value calculation operation end, or the feedforward target value A command signal is output at the end of storage in the storage unit 71, and the switch 63 and switch 64 of the feedback control unit 6 are switched by the signal to automatically return the feedback signal to the original state. Is good.

  As described above, in the present embodiment, when the drive information acquisition unit 5 acquires the drive information used when the target value calculation unit 9 calculates the feedforward target value, the target for temporarily acquiring the drive information is the target. The feed forward target value calculation is performed by switching from the drive unit 2 to the drive source 1, and the method of returning to the original control state at the end of the target value calculation is shown. During normal operation, the feedforward control using the feedforward target value calculated in this manner can effectively suppress drive fluctuations that occur in the driven unit 2.

[Embodiment 3]
Hereinafter, an embodiment of an image forming apparatus to which the present invention is applied will be described.
The present invention is an effective technique in all sheet-like member conveying apparatuses. As a configuration in which the effect of the present invention is most noticeable, an electrophotographic image forming apparatus including the sheet-like member conveying apparatus can be given. In an image forming apparatus, a sheet-like member conveying device is used in an intermediate transfer device, a fixing device, and a transfer fixing device. There are various types of image forming apparatuses and methods. Here, as a typical example, a tandem type image forming apparatus using an intermediate transfer method will be described.

  FIG. 17 shows an example of a tandem type image forming apparatus to which the present invention is applied. In the drawing, reference numeral 100 denotes a copying machine main body, 200 denotes a paper feed table on which the copying machine is placed, 300 denotes a scanner attached to the copying machine main body 100, and 400 denotes an automatic document feeder (ADF) attached to the scanner. Other symbols are directly cited in the detailed description.

  The image forming apparatus shown in FIG. 1 is a tandem type intermediate transfer (indirect transfer) type electrophotographic apparatus. The copying machine main body 100 is provided with an endless intermediate transfer belt 113 as an intermediate transfer member at the center. In the illustrated example, the intermediate transfer belt 113 is wound around three support rollers 114, 115, and 116 so as to be rotatable in the clockwise direction in FIG. Hereinafter, when the rotational movement of the belt is partially viewed, it is simply referred to as movement. An intermediate transfer belt cleaning device 117 for removing residual toner remaining on the intermediate transfer belt 113 after image transfer is provided on the left of the support roller 115 among the three support rollers. The support roller 115 also functions as a tension roller that keeps the tension of the intermediate transfer belt 113 constant, and pressure is applied from the inside to the outside of the intermediate transfer belt 113 by an elastic member such as a spring (not shown).

  Among the three support rollers, yellow (Y), magenta (M), and cyan (C) are arranged on the intermediate transfer belt 113 stretched between the support rollers 114 and 115 along the moving direction. , Black (K) image forming units 118Y, 118M, 118C, and 118K are arranged side by side to form a tandem image forming unit 120. In this embodiment, the support roller 114 is a drive roller. Further, an exposure device 121 is provided on the tandem image forming unit 120.

  Although an intermediate transfer belt type image forming apparatus is shown here, an intermediate transfer drum type image forming apparatus may be used. In this case, the intermediate transfer belt 113 and the support rollers 114, 115, and 116 are not necessary, and the image forming unit is arranged along the periphery of the intermediate transfer drum, not in a horizontal row. The present invention can be applied to an intermediate transfer device regardless of the intermediate transfer belt method or the intermediate transfer drum method.

  On the other hand, a secondary transfer device 122 is provided on the opposite side of the intermediate transfer belt 113 from the tandem image forming unit 120. The secondary transfer device 122 is arranged by pressing the secondary transfer roller 123 against the support roller 116 via the intermediate transfer belt 113, and simultaneously transfers the image on the intermediate transfer belt 113 to the sheet-like member. It is conveyed to the fixing device 124. Next to the secondary transfer device 122, a fixing device 24 for fixing the transferred image on the sheet-like member is provided. The secondary transfer device 22 is also provided with a sheet-like member conveying function for conveying the sheet-like member after image transfer to the fixing device 124.

  The fixing device 124 includes a heating roller 126, a fixing belt 125 stretched around the fixing roller 127, and a pressure roller 128 pressed against the fixing roller 127 via the fixing belt 125. The heating roller 126 also functions as a tension roller that keeps the tension of the fixing belt 125 constant, and pressure is applied from the inside to the outside of the fixing belt 125 by an elastic member such as a spring (not shown). The fixing belt 125 is heated to a temperature necessary for image fixing by a heating roller 126. The transfer image on the sheet-like member is fixed to the sheet-like member by applying heat and pressure. Although the belt fixing type image forming apparatus is shown here, a roller fixing type image forming apparatus including the heating roller 126 and the fixing roller 127 may be used.

  In the illustrated example, a sheet reversing device 129 for reversing the sheet to record images on both sides of the sheet is provided below the secondary transfer device 122 and the fixing device 124 in parallel with the tandem image forming unit 120 described above. Prepare.

  When making a copy using this image forming apparatus, the document is set on the document table 430 of the automatic document feeder 400. Alternatively, the automatic document feeder 400 is opened, a document is set on the contact glass 332 of the scanner 300, and the automatic document feeder 400 is closed and pressed by it. When a start switch (not shown) is pressed, when the document is set on the automatic document feeder 400, the document is conveyed and moved onto the contact glass 332. When a document is set on the contact glass 332, the scanner 300 is immediately driven. Next, the first traveling body 333 and the second traveling body 334 are caused to travel. Then, the first traveling body 333 emits light from the light source, and the reflected light from the document surface is further reflected toward the second traveling body 334, reflected by the mirror of the second traveling body 334, and passed through the imaging lens 335. The document is placed in a reading sensor 336 and the original content is read.

  In parallel with document reading, the support roller 114 is rotationally driven by a drive source (not shown), the other two support rollers 115 and 116 are driven to rotate, and the intermediate transfer belt 113 is rotationally driven. At the same time, in each image forming unit 118, the photosensitive drum 140 is rotated, and information on each color of yellow (Y), magenta (M), cyan (C), and black (K) is respectively displayed on each photosensitive drum 140. It is used for exposure and development to form a single color toner image. As the intermediate transfer belt 113 moves, the single color toner images are sequentially transferred to form a composite color image on the intermediate transfer belt 113.

  On the other hand, in parallel with the image formation, one of the paper feed rollers 242 of the paper feed table 200 is selectively rotated, and a sheet-like member is fed out from one of the paper feed cassettes 244 provided in multiple stages in the paper bank 243 to separate the separation roller 245. The sheets are separated one by one into the sheet feeding path 246, conveyed by the conveying roller 247, guided to the sheet feeding path in the copying machine main body 100, and abutted against the registration roller 149 and stopped. Alternatively, the sheet feeding roller 150 is rotated to feed out the sheet-like member on the manual feed tray 151, separated one by one by the separation roller 152, put into the manual feed path 153, and abutted against the registration roller 149 and stopped.

  Then, the registration roller 149 is rotated in synchronization with the composite color image on the intermediate transfer belt 113, and a sheet-like member is sent between the intermediate transfer belt 113 and the secondary transfer device 122, and transferred by the secondary transfer device 122. Then, a color image is recorded on the sheet-like member. After the image is transferred, the sheet-like member is heated and pressed by the fixing device 124 to fix the transferred image, and is then conveyed by the conveying roller 154 toward the sheet discharge tray, and is switched by the switching claw 155 to be discharged by the discharge roller 156. Are discharged and stacked on the discharge tray 157. Alternatively, the sheet is switched by the switching claw 155 and is put into the sheet reversing device 129, where it is reversed and guided again to the transfer position, and an image is recorded on the back side, and then ejected onto the sheet ejection tray 157 by the ejection roller 156.

  On the other hand, the intermediate transfer belt 113 after the image transfer is removed by the intermediate transfer belt cleaning device 117 to remove residual toner remaining on the intermediate transfer belt 113 after the image is transferred, so that the tandem image forming unit 120 can prepare for another image formation. Here, the registration roller 149 is generally used while being grounded, but it is also possible to apply a bias in order to remove the paper dust from the sheet-like member.

  It is often performed to make a black and white copy using this image forming apparatus. In that case, the intermediate transfer belt 113 is moved away from the photosensitive drums 140Y, 140C, and 140M by a displacement means (not shown) that displaces the intermediate transfer belt 113. These photosensitive drums are temporarily stopped from driving. Only the black photosensitive drum 140K contacts the intermediate transfer belt 113 to form and transfer an image.

  The present invention can be applied to both the secondary transfer device 122 and the fixing device 124 of the image forming apparatus.

  FIG. 18 shows an example of application to the secondary transfer device 122. Since the configuration is the same as that of the image forming apparatus shown in FIG. 17, the same numbers as those in FIG. 17 are used. Further, components not shown in FIG. 17 such as the control system are newly added.

  The feedback control unit 86 uses the driven information of the intermediate transfer belt 113 acquired by the encoder 84 so that the intermediate transfer belt 113 is driven in accordance with a target value such as a preset speed and the large diameter gear 82. A drive source 80 for driving the support roller 114 is controlled via the diameter gear 83.

  The feedforward control unit 87 performs feedforward control with respect to the non-periodic driving fluctuation generated in the intermediate transfer belt 113, and corrects the non-periodic driving fluctuation.

  The drive fluctuation of the intermediate transfer belt 113 which is a problem in the secondary transfer device 122 is a secondary transfer portion in which a sheet-like member 89 is formed at the pressure contact portion between the secondary transfer roller 123 and the support roller 116 as shown in FIG. It is noticeable when you enter. In order to suppress this fluctuation, feedforward control is effective.

  In FIG. 18, the sheet-like member detection means 85 is installed and used as a fluctuation prediction means. In addition to the method of using the sheet-like member detecting means 85, the fluctuation predicting means includes an operation signal of the registration roller 149 and the sheet-like member conveying roller 181 and the intermediate transfer when the sheet-like member 89 contacts the intermediate transfer belt 113. A method of detecting the drive fluctuation of the belt 113 with the encoder 84 can also be used.

  When performing the feedforward control, it is necessary to calculate a feedforward target value and store it in the feedforward control unit 87. Here, a procedure for calculating the feedforward target value in the image forming apparatus will be described.

  In the image forming apparatus, a switch for switching the feedback control gain of the intermediate transfer belt 113 is installed in advance. When calculating the feedforward target value, this switch temporarily switches the feedback control gain to a lower gain than in the normal state. In this state, the sheet-like member 89 is conveyed, and the speed fluctuation generated in the intermediate transfer belt 113 is measured by the encoder 84. The measured speed information is transmitted to the target value calculation means 88, the timing of feedforward control is calculated, and the feedforward target value is calculated by the target value calculation formula stored in the target value calculation means 88 in advance. The calculated timing and feedforward target value are stored in the feedforward control unit 87. When the calculation of the feedforward target value is completed, the feedback gain is returned to the normal state by the switch. When a plurality of sheet-like members are used, these procedures are repeated, a plurality of feedforward target values are stored in a table shape, and a feedforward target value corresponding to the sheet-like member to be used is called to perform feedforward control. .

  The above feedforward target value calculation method is the method shown in the first embodiment. However, when the method shown in the second embodiment is used, the drive information acquisition means 90 is installed as shown in FIG. In the feedback control unit 86, the signal from the encoder 84 and the signal from the drive information acquisition unit 90 may be switched. A switching switch or the like is installed in the image forming apparatus, and when the feedforward target value is calculated, the switch is switched to feed back a signal from the drive information acquisition means 90, and the sheet-like member 89 is conveyed in that state. Then, the speed fluctuation of the intermediate transfer belt 113 obtained by the encoder 84 is acquired. Similar to the above method, the feed-forward control timing and the feed-forward target value may be calculated using the acquired speed information and the target value calculation formula, and stored in the feed-forward control unit 87. After the calculation of the feedforward target value is completed, the original state where the signal from the encoder 84 is fed back may be restored by a switch operation.

  The optimum feedforward target value can be calculated by the method as described above, and is generated when the sheet-like member 89 enters the secondary transfer portion by performing feedforward control using these target values. In addition, the speed fluctuation of the intermediate transfer belt 113 can be effectively suppressed. The feedback control gain switching method, effect, and details of control are the same as those described in the first embodiment, the second embodiment, and the like, and are therefore omitted here.

  An example in which the present invention is applied to the fixing device 124 is shown in FIG. Since the configuration is the same as that of the image forming apparatus shown in FIG. 17, the same numbers as those in FIG. 17 are used. Further, components not shown in FIG. 17 such as a control system are also added. When applied to both the intermediate transfer device and the fixing device 24, the configurations shown in FIGS. 18, 19, and 20 may be combined.

  In the present embodiment, when switching the feedback control gain or switching the feedback control target manually, it is possible to forget the operation of returning to the original state after calculating the feedforward target value. If image formation is performed in this state, the feedback control system is not in an optimal state, which causes a problem that the quality of the formed image is deteriorated.

  In order to solve this problem, it is desirable that the feedback system automatically return to the normal state after calculating the feedforward target value. Therefore, a command signal is output when the feedforward target value calculation speed fluctuation information acquisition ends, when the feedforward target value calculation operation ends, or when the feedforward target value is stored in the feedforward control unit 87, etc. It is only necessary to automatically perform a switch operation for returning to the original state.

  Also, the image forming apparatus has a function capable of selecting a feedforward target value calculation mode, and when the feedforward target value calculation mode is selected, the feedforward is automatically switched and the feedback control target is switched. When the target value calculation mode is entered and the sheet-like member is conveyed, the feedforward timing and the feedforward target value are calculated, and after the calculation of the feedforward target value is completed, the original state (normal state) is restored. What should I do? By providing such a function, it is possible to solve the problem that the operation for returning to the normal state is forgotten after the feedforward target value is calculated and the quality of the formed image is deteriorated.

[Embodiment 4]
Hereinafter, another embodiment of the image forming apparatus to which the present invention is applied will be described.
FIG. 21 shows an example of an image forming apparatus having a transfer fixing device 266 that simultaneously transfers and fixes an image onto a sheet. Since the image forming process is the same as that of the image forming apparatus shown in FIG. 17 except for the transfer fixing unit, a detailed description of functions other than the transfer fixing unit is omitted.

  In the image forming apparatus illustrated in FIG. 21, the sheet-like member heating device 267, the transfer fixing roller 228, and the pressure roller 268 constitute a transfer fixing unit. The shape of the sheet-like member heating device 267 is not limited to a roller shape other than the plate shape shown in FIG. Also, the shape of the pressure roller 268 such as the pressure pad and the pressure belt is not limited to the roller.

  The sheet-like member fed out from the paper feed cassette 261 is conveyed to the transfer fixing unit by a sheet-like member conveyance device including a paper supply roller 262, a conveyance path 263, conveyance rollers 264a and 264b, registration rollers 265a and 265b, and the like. . In the transfer fixing unit, first, the surface of the sheet-like member is heated by the sheet-like member heating device 267 to a temperature sufficient to melt the toner. The heated sheet-like member is caught in a nip formed by the transfer fixing roller 228, the pressure roller 268 and the intermediate transfer belt 113. At this time, the toner image on the intermediate transfer belt 113 is melted by the heat of the sheet-like member, and is simultaneously transferred and fixed onto the sheet-like member by being pressurized at the nip portion.

  FIG. 22 shows an example of a transfer fixing device 512 having a different form from the transfer fixing device of FIG. The transfer fixing device of FIG. 22 is mainly composed of a second intermediate transfer member 513 and a pressure roller 514. The toner image on the intermediate transfer belt 113 is secondarily transferred onto the second intermediate transfer member 513. The second intermediate transfer member 513 has a heating device 515 inside thereof, and melts the second-transferred toner image on the surface thereof. The toner image melted on the second intermediate transfer member 513 is pressed at a nip portion N formed by the second intermediate transfer member 513 and the pressure roller 514, and is transferred and fixed onto the sheet-like member. The

  Here, the second intermediate transfer member 513 may have an endless belt shape, and is not limited to the roller shape shown in FIG. Further, the shape and method of the heating device 515 such as a halogen heater, a ceramic heater, or an IH heating device is not limited. Similarly, the shape and method of the pressure roller 514 are not limited to the method shown in FIG.

  The present invention can be applied to an image forming apparatus having the above-described transfer fixing device. An example in which the present invention is applied to a transfer fixing apparatus is shown in FIGS. Since the basic configuration is the same as that of the image forming apparatus shown in FIGS. 21 and 22, the same reference numerals as those in FIGS. 21 and 22 are used. Further, configurations not shown in FIGS. 21 and 22 such as the control system are also added. The details of the application to the transfer fixing device are the same as those applied to the intermediate transfer device and the fixing device of the third embodiment, and will be omitted.

  Also in this embodiment, it is desirable to have a function of automatically returning to the normal state after calculating the feedforward target value by setting the feedforward target value calculation mode or the like.

As described above, according to the present embodiment, the drive source, the driven unit driven by the drive source, the drive transmission unit that transmits the drive from the drive source to the driven unit, and the driven information of the driven unit are acquired. Drive information acquisition means, feedback control section that performs drive control of the drive source using the driven information acquired by the drive information acquisition means, and drive fluctuation against non-periodic drive fluctuation generated in the driven section In a drive device having a feedforward control unit that performs feedforward control using a feedforward target value to be erased, and a fluctuation prediction unit that predicts the timing of occurrence of an aperiodic drive fluctuation, the feedback control unit has a plurality of control gains. The control gain is switched to a lower gain than during normal operation, and feedforward control is performed by the feedforward control unit. A free, using a driven information acquired by the driving information acquisition means when operating the apparatus body, and a target value calculating means for calculating a feedforward target value. As a result, the effect of suppressing the drive fluctuation of the driven part by the feedback control is reduced as compared with the case where the feedback control is performed using the control gain during the normal operation, and the drive fluctuation becomes noticeable as the effect is reduced. . Therefore, the feed-forward target value is calculated by the target value calculation means using the driven information acquired by the drive information acquisition means and in which the drive fluctuation becomes significant. Therefore, by performing feedforward control using the feedforward target value calculated in this way, the above-described drive fluctuation that has been suppressed by feedback control in a conventional drive device can be suppressed by feedforward control. . Therefore, it is possible to suppress the drive fluctuation of the driven part that is suppressed when only the feedback control is performed from occurring when the feedforward control and the feedback control are performed in combination. Therefore, it is possible to satisfactorily suppress the drive fluctuation of the driven part when the feedback control and the feedforward control are used together.
Further, according to the present embodiment, the drive source, the driven unit driven by the drive source, the drive transmission unit that transmits the drive from the drive source to the driven unit, and the driven information of the driven unit are detected. A first drive information acquisition unit, a feedback control unit that performs drive control of the drive source using the driven information acquired by the first drive information acquisition unit, and aperiodic drive fluctuations that occur in the driven unit. In a drive apparatus having a feedforward control unit that performs feedforward control using a feedforward target value that cancels drive fluctuations, and fluctuation prediction means that predicts the timing of occurrence of non-periodic drive fluctuations, A second drive information acquisition unit configured to acquire drive information, and the feedback control unit performs drive control of the drive source using the drive information acquired by the second drive information acquisition unit; The feedforward target value is calculated using the driven information acquired by the first drive information acquisition means when the apparatus main body is operated without performing the feedforward control by the feedforward control unit. A target value calculation means is provided. As a result, it is possible to suppress the drive fluctuation of the driven part by the feedback control, compared to the case of performing feedback control that controls the drive part using the driven information of the driven part and suppresses the drive fluctuation of the driven part. As the effect is reduced, the drive fluctuation of the driven part becomes remarkable. Accordingly, the feedforward target value is calculated by the target value calculation means using the driven information acquired by the first driving information acquisition means and in which the drive fluctuation of the driven part becomes significant. Therefore, the feedforward control is performed using the feedforward target value calculated in this way, so that the drive fluctuations of the driven parts that are suppressed by the feedback control in the conventional driving device are suppressed by the feedforward control. be able to. Therefore, it is possible to suppress the drive fluctuation of the driven part that is suppressed when only the feedback control is performed from occurring when the feedforward control and the feedback control are performed in combination. Therefore, it is possible to satisfactorily suppress the drive fluctuation of the driven part when the feedback control and the feedforward control are used together.
Further, according to the present embodiment, the position resolution equivalent to the driven part of the first drive information acquisition unit and the position resolution equivalent to the driven part of the second drive information acquisition unit are equal, Since the signals output from the first drive information acquisition unit and the second drive information acquisition unit are equal, the configuration of the feedback control system can be simplified.
Further, according to the present embodiment, the drive source is driven and controlled by a PLL system, and the position resolution of the first drive information acquisition unit is equal to the position resolution of the second drive information acquisition unit and the drive transmission. Product of the reduction ratio of the part. When drive control of the drive source is performed by the PLL method, it is necessary to match the phase and frequency of the clock signal obtained by the drive information acquisition unit and the target clock signal. When the frequency of the clock signal obtained from the first drive information acquisition unit and the second drive information acquisition unit is different, it is necessary to make it possible to generate two target clocks or to install two PLL controllers. Leads to an increase in Therefore, the increase in cost is prevented by setting the resolutions of the respective drive information acquisition means so that the frequencies of the clock signals obtained from the first drive information acquisition means and the second drive information acquisition means are equal. can do.
Further, according to the present embodiment, the photosensitive drum that is a latent image carrier that carries the latent image, the developing unit that develops the latent image on the photosensitive drum into a toner image, and the toner image on the photosensitive drum. Intermediate transfer means for transferring to an intermediate transfer belt that is an intermediate transfer member, secondary transfer device that is a secondary transfer means for transferring a toner image transferred to the intermediate transfer belt to a sheet-like member, and transferred to the sheet-like member In the image forming apparatus provided with a fixing device which is a fixing means for fixing the toner image to the sheet-like member, the driving device of the present invention is used as at least one driving means of the intermediate transfer means and the fixing device. When a sheet-like member of a certain thickness enters or leaves the press contact part of the secondary transfer device or the fixing device of the image forming apparatus, driving fluctuations of the intermediate transfer belt and the fixing device occur, and the formed image There is a problem that quality deteriorates. Therefore, by applying the driving device of the present invention to the driving means such as the intermediate transfer means and the fixing device, the driving fluctuation can be suppressed and the deterioration of the image quality can be suppressed.
Further, according to the present embodiment, the photosensitive drum that is a latent image carrier that carries the latent image, the developing unit that develops the latent image on the photosensitive drum into a toner image, and the toner image on the photosensitive drum. An image forming apparatus comprising: an intermediate transfer unit that transfers to an intermediate transfer belt that is an intermediate transfer member; and a transfer fixing device that is a transfer fixing unit that transfers and fixes a toner image transferred to the intermediate transfer belt onto a sheet-like member. The drive device of the present invention is used as the drive means of the intermediate transfer means. When a sheet-like member having a certain thickness or more enters or leaves the pressure contact portion of the transfer fixing device, there is a problem that the drive fluctuation of the intermediate transfer belt occurs and the quality of the formed image is lowered. Therefore, by applying the driving device of the present invention to the driving unit of the intermediate transfer unit, the driving fluctuation can be suppressed and the deterioration of image quality can be suppressed.
Further, according to the present embodiment, the photosensitive drum that is a latent image carrier that carries the latent image, the developing unit that develops the latent image on the photosensitive drum into a toner image, and the toner image on the photosensitive drum. Intermediate transfer means for transferring to the intermediate transfer belt, which is an intermediate transfer body, secondary transfer means for transferring the toner image transferred to the intermediate transfer belt to the second intermediate transfer body, and transfer to the second intermediate transfer body In the image forming apparatus provided with a transfer fixing device that is a transfer fixing device for transferring and fixing the toner image to the sheet-like member, the driving device of the present invention is used as at least one of the intermediate transfer device and the secondary transfer device. Is used. The quality of the image formed due to fluctuations in the drive of the intermediate transfer belt or the secondary transfer means when a sheet-like member of a certain thickness enters or leaves the press contact part of the secondary transfer means or the transfer fixing device. There is a problem that decreases. Therefore, by applying the driving device of the present invention to the intermediate transfer unit or the driving unit of the second intermediate transfer member, the driving fluctuation can be suppressed and the image quality can be prevented from deteriorating.
According to this embodiment, the image forming apparatus has a target value calculation mode for calculating the feedforward target value. When calculating the feedforward target value during setup or user use, the feedforward target value may be calculated without switching the feedback control gain or switching the feedback signal. The forward control effect cannot be obtained. In addition, there is a problem that it is necessary to return the feedback gain and feedback signal switched at the time of target value calculation to the original state, and if this operation is not performed, all images formed thereafter will be deteriorated. is there. Therefore, a function of shifting to an operation mode for calculating a feedforward target value such as a feedforward target value calculation mode is added to the image forming apparatus, and when the feedforward target value calculation mode is selected, it is automatically The above problem can be solved by switching the feedback control gain or the feedback signal and automatically returning to the original state when the target value calculation is completed.

FIG. 3 is a block diagram illustrating an example of a drive control unit according to the first embodiment. FIG. 3 is a schematic diagram illustrating an example of a drive device according to the first embodiment. FIG. 5 is a schematic diagram illustrating another example of the drive device according to the first embodiment. The schematic diagram which shows an example of an aperiodic drive fluctuation generation source. The schematic diagram which shows another example of an aperiodic drive fluctuation generation source. The schematic diagram which shows another example of an aperiodic drive fluctuation generation source. The schematic diagram which shows another example of an aperiodic drive fluctuation generation source. The schematic diagram which shows another example of an aperiodic drive fluctuation generation source. The schematic diagram which shows another example of an aperiodic drive fluctuation generation source. The graph which showed the speed fluctuation of the intermediate transfer body at the time of cardboard rush. The figure used for description of a feedforward target value and feedforward timing. The graph which showed the speed fluctuation of the intermediate transfer body at the time of cardboard rush. FIG. 6 is a schematic diagram illustrating an example of a drive device according to a second embodiment. FIG. 6 is a schematic diagram illustrating another example of a drive device according to the second embodiment. FIG. 4 is a block diagram illustrating an example of a drive control unit according to a second embodiment. FIG. 6 is a block diagram illustrating another example of a drive control unit according to the second embodiment. FIG. 5 is a schematic configuration diagram of an image forming apparatus according to a third embodiment. The schematic diagram which shows an example of a secondary transfer part. FIG. 6 is a schematic diagram illustrating another example of a secondary transfer unit. FIG. 3 is a schematic diagram illustrating an example of a secondary transfer unit and a fixing unit. FIG. 6 is a schematic configuration diagram of an image forming apparatus according to a fourth embodiment. FIG. 10 is a schematic configuration diagram of another image forming apparatus according to the fourth embodiment. FIG. 2 is a schematic diagram of a transfer fixing device. FIG. 2 is a schematic diagram of a transfer fixing device. The conceptual diagram of feedforward control. The conceptual diagram of the conversion from a speed fluctuation to a feedforward target value. The graph which showed the speed fluctuation | variation of the intermediate transfer body at the time of cardboard rush in the case of a low gain. The graph which showed the speed fluctuation | variation of the intermediate transfer body at the time of cardboard rush in the case of high gain. The graph which showed the speed fluctuation of the intermediate transfer body at the time of cardboard rush.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drive source 2 Drive part 3 Small diameter gear 3 Patent document 4 Large diameter gear 5 Drive information acquisition means 6 Feedback control part 7 Feed forward control part 8 Fluctuation prediction means 9 Target value calculation means 10 Drive roller 11 Support roller 12 Support roller 13 Support roller 14 Endless belt 15 Drive information acquisition means 22 Secondary transfer device 24 Fixing device 30 Endless belt 41 Slide member 42 Actuator 43 Pressure member 44 Tension member 45 Actuator 46 Pressure member 47 Tension member 48 Sheet-like member 51 Conveying roller 53 Roller member 54 Roller member 60 Feedback gain 61 Feedback gain 62 Switch 63 Switch 64 Switch 71 Storage unit 80 Drive source 82 Small diameter gear 83 Large diameter gear 84 Encoder 85 Sheet-like member detection means 86 Fee Back control unit 87 Feed forward control unit 88 Target value calculation unit 89 Sheet-like member 90 Drive information acquisition unit 91 Storage unit 100 Copier body 113 Intermediate transfer belt 114 Support roller 115 Support roller 116 Support roller 117 Intermediate transfer belt cleaning device 118 Image Forming means 120 Tandem image forming unit 121 Exposure device 122 Secondary transfer device 123 Secondary transfer roller 124 Fixing device 125 Fixing belt 126 Heating roller 127 Fixing roller 128 Pressure roller 129 Sheet reversing device 140 Photosensitive drum 149 Registration roller 150 Paper feed Roller 151 Tray 152 Separation roller 153 Feed path 154 Transport roller 155 Switching claw 156 Discharge roller 157 Discharge tray 181 Sheet-shaped member transport roller 200 Feed table 22 8 Transfer fixing roller 242 Paper feed roller 243 Paper bank 244 Paper feed cassette 245 Separating roller 246 Paper feed path 247 Transport roller 261 Paper feed cassette 262 Paper feed roller 263 Transport path 264 Transport roller 265 Registration roller 266 Transfer fixing device 267 Sheet-like member Heating device 268 Pressure roller 300 Scanner 332 Contact glass 333 Traveling body 334 Traveling body 335 Imaging lens 336 Sensor 400 Automatic document feeder 430 Document table 512 Transfer fixing device 513 Intermediate transfer member 514 Pressure roller 515 Heating device

Claims (8)

  1. A driving source;
    A driven part driven by the drive source;
    A drive transmission unit for transmitting drive from the drive source to the driven unit;
    Driving information acquisition means for acquiring driven information of the driven part;
    A feedback control unit that performs drive control of the drive source using the driven information acquired by the drive information acquisition unit;
    A feed-forward control unit that performs feed-forward control using a feed-forward target value that cancels out the driving variation with respect to the non-periodic driving variation generated in the driven unit;
    In a driving device having fluctuation prediction means for predicting the timing of occurrence of the non-periodic driving fluctuation,
    The feedback control unit has a plurality of control gains,
    The drive gain is acquired by the drive information acquisition means when the control gain is switched to a lower gain than in normal operation, and the apparatus main body is operated without performing feedforward control by the feedforward control unit. A drive apparatus comprising: target value calculation means for calculating the feedforward target value using driven information.
  2. A driving source;
    A driven part driven by the drive source;
    A drive transmission unit for transmitting drive from the drive source to the driven unit;
    First driving information acquisition means for detecting driven information of the driven part;
    A feedback control unit that performs drive control of the drive source using the driven information acquired by the first drive information acquisition unit;
    A feedforward control unit that performs feedforward control using a feedforward target value that cancels the drive fluctuation with respect to the aperiodic drive fluctuation generated in the driven part;
    In a driving device having fluctuation prediction means for predicting the timing of occurrence of the non-periodic driving fluctuation,
    Second driving information acquisition means for acquiring driving information of the driving source;
    The feedback control unit performs drive control of the drive source using the drive information acquired by the second drive information acquisition unit, and does not perform feedforward control by the feedforward control unit, and the apparatus main body A drive apparatus comprising: target value calculation means for calculating the feedforward target value using the driven information acquired by the first drive information acquisition means when the is operated.
  3. The drive device according to claim 2, wherein
    A driving apparatus characterized in that a driven part equivalent position resolution of the first driving information acquisition means is equal to a driven part equivalent position resolution of the second driving information acquisition means.
  4. The drive device according to claim 2, wherein
    The drive source is driven and controlled by a PLL system, and the position resolution of the first drive information acquisition unit is the product of the position resolution of the second drive information acquisition unit and the reduction ratio of the drive transmission unit. A drive device characterized by that.
  5. A latent image carrier for carrying a latent image;
    Developing means for developing the latent image on the latent image carrier into a toner image;
    Intermediate transfer means for transferring the toner image on the latent image carrier to an intermediate transfer member;
    Secondary transfer means for transferring the toner image transferred to the intermediate transfer member to a sheet-like member;
    An image forming apparatus comprising: a fixing unit that fixes the toner image transferred to the sheet-like member to the sheet-like member;
    5. An image forming apparatus using the driving device according to claim 1, 2, 3 or 4 as at least one of the intermediate transfer unit and the fixing unit.
  6. A latent image carrier for carrying a latent image;
    Developing means for developing the latent image on the latent image carrier into a toner image;
    Intermediate transfer means for transferring the toner image on the latent image carrier to an intermediate transfer member;
    In an image forming apparatus comprising transfer fixing means for transferring and fixing a toner image transferred to the intermediate transfer member to a sheet-like member,
    An image forming apparatus using the driving device of claim 1, 2, 3, or 4 as a driving unit of the intermediate transfer unit.
  7. A latent image carrier for carrying a latent image;
    Developing means for developing the latent image on the latent image carrier into a toner image;
    Intermediate transfer means for transferring the toner image on the latent image carrier to an intermediate transfer member;
    Secondary transfer means for transferring the toner image transferred to the intermediate transfer body to the second intermediate transfer body, and transfer fixing means for transferring and fixing the toner image transferred to the second transfer body to the sheet-like member In an image forming apparatus comprising:
    5. An image forming apparatus using the driving device according to claim 1, 2, 3 or 4 as at least one of the intermediate transfer unit and the secondary transfer unit.
  8. The image forming apparatus according to claim 5, 6 or 7.
    An image forming apparatus having a target value calculation mode for calculating the feedforward target value.
JP2008233648A 2008-09-11 2008-09-11 Driving device and image forming apparatus Active JP5117332B2 (en)

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JP2014182374A (en) * 2013-03-15 2014-09-29 Xerox Corp Improving motionquality of transfix nip using media thickness and/or skew feedforward to nip motor torque
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JP2014182374A (en) * 2013-03-15 2014-09-29 Xerox Corp Improving motionquality of transfix nip using media thickness and/or skew feedforward to nip motor torque

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