JP2011107423A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus with which recovery time is shortened. <P>SOLUTION: The image forming apparatus 1 (such as a four-cycle type full-color printer) includes: a predetermined driven body (rotating developing rack, etc.); a capacitor 55 which stores regenerative energy regarding the driven body (developing rack, etc.) as electrical energy at emergency; and a drive control part 110. The drive control part 110, immediately after emergency stop, drives the driven body (developing rack 20, etc.) to a predetermined reference position (standby position PG1, etc.) using the energy stored in the capacitor 55. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a printer or an MFP (multifunction peripheral).

  In an image forming apparatus, there is a technique for charging a secondary battery with regenerative energy of a driven body (see Patent Document 1, etc.).

  For example, Patent Document 1 discloses an image forming apparatus that accumulates regenerative power of an actuator or the like in a secondary battery.

JP 2007-178039 A

  By the way, during the printing operation of the image forming apparatus, the driving operation of a predetermined driven body in the image forming apparatus may be stopped due to a paper jam or the like. In such a case, when the driving operation of the predetermined driven body is resumed again in response to the operation resuming instruction after the restoration, an operation for returning the driven body to the standby position is performed first, and then Various operations (such as other initial operations and actual printing operations) are performed.

  However, in such an operation, since the operation of returning the driven body to the standby position is started after the time when the operation resumption instruction is given, the driven body is again moved to the standby position and ready for printing. There is a problem that the time until recovery is completed (recovery time) becomes relatively long.

  In the above Patent Document 1, only a technique for storing merely the secondary battery the regenerative power or the like of the actuator of the image forming apparatus is shown, also similar in the above-described problems in the device described in Patent Document 1 Can occur.

  Accordingly, an object of the present invention is to provide an image forming apparatus capable of shortening the recovery time.

  In order to solve the above problems, the invention of claim 1, an image forming apparatus, a storage means for storing a predetermined driven member, the regenerative energy related to the predetermined driven body at the time of an emergency stop as electric energy Drive control means for returning the predetermined driven body toward a predetermined reference position using energy stored in the power storage means immediately after the emergency stop is provided.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect of the present invention, the image forming apparatus further includes a non-volatile memory that stores a current position of the predetermined driven body after the return driving, and the drive control unit includes: When the operation is resumed after the emergency stop, the predetermined driven body is moved to the predetermined reference position based on the current position stored in the nonvolatile memory.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect of the present invention, the image forming apparatus further comprises thermoelectric conversion means for converting thermal energy of a predetermined heat generating portion into electric energy, Immediately after an emergency stop, the driven body is driven using also the electric energy generated by the thermoelectric conversion means.

  According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the predetermined driven body is a rotary type provided in a four-cycle electrophotographic image forming apparatus. It is a developing rack.

  According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the predetermined driven body is a photosensitive drum.

  According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, the second driven body other than the first driven body, which is the predetermined driven body, is provided. The predetermined reference position is a reference position of the first driven body, and the control means uses the electric power stored in the power storage means during the emergency stop. The driven body and the second driven body are driven, the first driven body is driven toward the first reference position, and the second driven body is driven by the second driven body. It is characterized by being driven toward the reference position of the body.

  According to a seventh aspect of the invention, in the image forming apparatus according to the sixth aspect of the invention, the second driven body is a pressure contact / separation mechanism of a fixing device.

  According to an eighth aspect of the present invention, in the image forming apparatus according to the sixth aspect of the invention, the second driven body is a pressure contact / separation mechanism of a transfer unit.

  The invention of claim 9 includes a plurality of driven body, it is very power storage means for the regeneration energy for said plurality of the driven body at stop time accumulate as electrical energy, the amount of power stored in the storage means the storage amount A storage amount calculation means for calculating the required power amount, a required power amount calculation means for calculating each required power amount that is an amount of power for returning the plurality of driven bodies to their respective reference positions, and the plurality of driven bodies. Based on the storage time, each required power amount, and each required return time, a return time calculating means for calculating each required return time required to return each current position from each current position to each reference position, A determination unit that determines a drive target to be driven immediately after the emergency stop among the plurality of driven bodies, and a regenerative energy accumulated in the power storage unit immediately after the emergency stop. Characterized in that it comprises a drive control means for driving toward the plurality of the driven object of the driven body that is determined by the determining means of the driven member to the reference position.

  According to a tenth aspect of the present invention, in the image forming apparatus according to the ninth aspect of the invention, the determining means determines the required return time among the plurality of driven bodies based on the power storage amount and the required power amounts. When it is determined that the N driven bodies selected according to the priority order according to the above can be returned to the respective reference positions, the N driven bodies are determined as the driving targets. It is characterized by that.

  The invention of claim 11 is an image forming apparatus according to the invention of claim 9 or claim 10, nonvolatile storage means for storing respective current position immediately after emergency stop of the plurality of the driven body, further comprising a Features.

  According to a twelfth aspect of the present invention, in the image forming apparatus according to any one of the ninth to eleventh aspects of the present invention, the image forming apparatus further includes thermoelectric conversion means for converting thermal energy of a predetermined heat generating portion into electrical energy, The calculating means calculates a value including the amount of power stored in the power storage means by the thermoelectric conversion means as the power storage amount.

  According to the first to eighth aspects of the invention, immediately after an emergency stop, the predetermined driven body is driven toward the predetermined reference position using the energy stored in the power storage means. It is possible to shorten the recovery time when the operation is resumed.

  In particular, according to the second aspect of the present invention, since the current position immediately after the return drive of the predetermined driven body is stored in the nonvolatile memory, the power is temporarily turned off during the emergency stop period. In the recovery operation after resuming the operation, it is possible to easily move the predetermined driven body to the reference position by reading the current position stored in the nonvolatile memory.

  Particularly, according to the invention described in claim 3, immediately after an emergency stop, because even with electric energy generated by the thermoelectric converter driven member is driven, predetermined driven body is a predetermined reference It becomes easy to reach the position.

  Further, according to the invention described in claims 9 to 12, immediately after the emergency stop, the driven body to be driven among the plurality of the driven body with the energy stored in the energy storage means to the reference position Therefore, it is possible to shorten the recovery time when restarting the subsequent operation. In addition, a drive target to be driven immediately after an emergency stop among a plurality of driven bodies is determined based on the stored power amount, each required power amount, and each required return time, and the regenerative energy accumulated in the power storage means is determined. In use, immediately after the emergency stop, the driven body to be driven among the plurality of driven bodies is driven toward the reference position, so that the recovery time can be further shortened.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to a first embodiment. FIG. 2 is a diagram illustrating a detailed configuration of a rotary developing rack. 2 is a functional block diagram of the image forming apparatus. FIG. It is a figure which shows a mode that the image development rack is rotating. FIG. 6 is a diagram illustrating a state in which the developing rack has stopped due to a paper jam or the like. FIG. 6 is a diagram illustrating a state in which the developing rack has moved to a position immediately before a standby position by a return operation. FIG. 6 is a diagram illustrating a state in which a development rack exists at an origin position. FIG. 3 is a diagram illustrating a state in which a development rack is present at a standby position. It is a figure which shows the electric power supply state in normal operation | movement (print operation and reprint operation). It is a figure which shows charging operation. It is a figure which shows the electric power supply state in return operation | movement. It is a figure which shows the image forming apparatus which concerns on 2nd Embodiment. It is a figure which shows charging operation. It is a flowchart which shows the operation | movement which concerns on 3rd Embodiment. It is a figure which shows the functional block of the control part which concerns on 3rd Embodiment. It is a figure which shows the data table in which the regenerative electric power value according to the rotation state of a developing rack is stored. It is a figure which shows the acceleration / deceleration pattern of the developing rack at the time of normal operation. It is a figure which shows the data table in which each required electric power for every to-be-driven body was stored. It is a figure which shows the data table in which the regenerative electric power value regarding a photoconductor was stored. It is an electric circuit diagram which monitors the electrical storage amount of an electrical storage device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<1. First Embodiment>
<1-1. Device configuration>
FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus 1 (1A) according to the present embodiment. The image forming apparatus 1 is an apparatus that develops an electrostatic latent image on a photoreceptor (also referred to as an image carrier) to form an image. Here, as the image forming apparatus, an electrophotographic apparatus, more specifically, a four-cycle full-color electrophotographic apparatus is illustrated.

  As shown in FIG. 1, the image forming apparatus 1 includes a photoconductor (image carrier) 11, a charger 12, an exposure device 13, and a rotary developing rack (rotary developing device) 20.

  The photoconductor 11 has a substantially cylindrical shape and is also expressed as a photoconductive drum. The charger 12 is a device that uniformly charges the outer peripheral surface of the photoconductor 11. The exposure device 13 is a device that selectively irradiates the outer peripheral surface of the photoconductor 11 with light.

  The photoconductor 11 is provided with a drive mechanism (such as a motor and a gear) that rotates the photoconductor 11 about the rotation axis AX8.

  As shown in FIG. 2, the developing rack 20 includes a plurality (specifically, four) developing units 21 (specifically, 21Y, 21M, 21C, and 21K). Specifically, the developing rack 20 includes a yellow developing unit 21Y, a magenta developing unit 21M, a cyan developing unit 21C, and a black developing unit 21K. The developing units 21 have substantially the same configuration except that different color toners are stored.

  Each developing unit 21 includes a developing roller 14, a supply roller 15, and a toner storage unit 28. The toner storage unit 28 stores toner TN. Specifically, yellow toner is accommodated in the toner accommodating portion 28 of the developing unit 21Y, and magenta toner is accommodated in the toner accommodating portion 28 of the developing unit 21M. Similarly, cyan toner is accommodated in the toner accommodating portion 28 of the developing unit 21C, and black toner is accommodated in the toner accommodating portion 28 of the developing unit 21K. Since each developing unit 21 is a replaceable member that also stores toner, it is also referred to as a toner cartridge.

  The developing rack 20 is provided to be rotatable about a predetermined axis AX1. A motor (also referred to as “rack motor”) 20 </ b> R that rotationally drives the developing rack 20 and a rack docking gear 20 </ b> G are provided in the vicinity of the developing rack 20 (the lower side in the drawing).

  The rack docking gear 20G is provided so as to mesh with a gear fixed to one end surface of the developing rack 20 having a substantially cylindrical shape, and is also provided so as to mesh with a gear fixed to the rotation shaft of the rack motor 20R. Yes.

  The rotational driving force of the rack motor 20R is transmitted to the developing rack 20 via the rack docking gear 20G, and the developing rack 20 rotates about the axis AX1. Specifically, when the rack motor 20R rotates counterclockwise about the axis AX2, the rack docking gear 20G rotates clockwise about the axis AX3. As the rack docking gear 20G rotates, the developing rack 20 further rotates counterclockwise (forward rotation direction) about the axis AX1. The developing rack 20 can be rotated in the reverse direction by the driving force in the reverse direction (clockwise) of the rack motor 20R.

  The image forming apparatus 1 sequentially moves the four developing units 21 to a position facing the photoconductor 11 by rotating the developing rack 20. Then, the electrostatic latent image formed on the outer peripheral surface of the photoconductor 11 is developed using the corresponding color toner.

  Specifically, after the outer peripheral surface of the photoconductor 11 is charged by the charger 12 (see FIG. 1), the charge of the portion exposed by the exposure device 13 is reduced, so that the outer peripheral surface of the photoconductor 11 is statically exposed. An electrostatic latent image is formed. The electrostatic latent image is formed for each basic color component (specifically, each component of Y (yellow), M (magenta), C (cyan), and K (black)) in the final output image. .

  Each electrostatic latent image is developed by one of the plurality of development units 21 in the development rack 20. When appropriate development unit 21 of the plurality of developing units 21 are moved to the position opposite to the photosensitive member 11 facing the photosensitive member 11, in accordance with the rotation of the developing roller 14 of the developing unit 21, the developing unit The toner in 21 is supplied to the photoreceptor. Thereby, the electrostatic latent image on the photoconductor 11 is developed.

  Specifically, the yellow component electrostatic latent image is developed by the yellow developing unit 21Y, and the magenta component electrostatic latent image is developed by the magenta developing unit 21M. Similarly, the cyan component electrostatic latent image is developed by the cyan developing unit 21C, and the black component electrostatic latent image is developed by the black developing unit 21K. Thus, each developing unit 21 forms a toner image of each basic color component by an electrophotographic method.

  In full-color printing, the above four-color toner image forming operations are sequentially executed. More specifically, first, an electrostatic latent image forming operation and a developing operation relating to the yellow component are executed, and then an electrostatic latent image forming operation and a developing operation relating to the magenta component are executed. Thereafter, an electrostatic latent image forming operation and a developing operation relating to the cyan component are executed, and finally, an electrostatic latent image forming operation and a developing operation relating to the black component are executed.

  The toner image formed by the developing units 21 is thus transferred sequentially to the intermediate transfer belt in the (also referred intermediate transfer body) 31 (FIG. 1), is superimposed on the intermediate transfer belt 31.

  The intermediate transfer belt 31 is moved in the direction of the arrow AR <b> 1 by driving of the driving roller 33. A secondary transfer roller 32 is provided at a position facing the drive roller 33 with the intermediate transfer belt 31 therebetween. The secondary transfer roller 32 can be linearly moved in the horizontal direction in the figure by a drive mechanism (solenoid or the like) 34 (not shown), and can be switched between a pressure contact state and a separated state with the drive roller 33.

  At the time of secondary transfer, both the driving roller 33 and the secondary transfer roller 32 are pressed against each other, and the paper PA passes through the portion sandwiched between the two, so that the toner image of each basic color component superimposed on the intermediate transfer belt 31 is obtained. Is further transferred onto a sheet (recording sheet) PA. Thereby, a full-color image is formed on the paper PA. Note that the paper PA is supplied from the lower (upstream) paper supply unit 40 of the secondary transfer roller 32 or the like toward the upper (downstream) secondary transfer roller 32 or the like in the drawing.

  A fixing device 45 is provided on the downstream side (upper side in FIG. 1) of the paper PA that has passed the position of the secondary transfer roller 32, and a paper discharge unit 46 is provided on the downstream side in the transport direction. It has been. Note that one fixing roller of the pair of roller pairs in the fixing device 45 can be linearly moved in the left-right direction in the drawing by a drive mechanism (solenoid or the like) 44 (not shown), and the one pair of roller pairs. It is possible to switch between the pressure contact state and the separated state.

  The toner image transferred onto the paper PA is heated by the fixing device 45 and fixed on the paper PA. Thereafter, the paper PA is discharged to the paper discharge unit 46 on the upper side of the image forming apparatus 1.

  The image forming apparatus 1 prints out an image based on image data transmitted from another information device (personal computer or the like) connected via a network or the like by using the printing mechanism as described above. Functions as a color page printer.

  FIG. 3 is a functional block diagram of the image forming apparatus 1. As shown in FIG. 3, the image forming apparatus 1 further includes a power supply unit 53, a capacitor 55, a switching unit 57, and a control unit (controller) 100.

  The control unit 100 includes a CPU, a RAM, a ROM (EEPROM), and the like, and controls various operations in the image forming apparatus 1. For example, the drive operation of each driven body related to the print output operation is controlled.

  As shown in FIG. 3, the control unit 100 (also referred to as 100 </ b> A) includes processing units such as the drive control unit 110. Each processing unit is functionally realized by executing a predetermined program in the CPU of the control unit 100A.

  The drive control unit 110 can switch the power supply source for the drive unit of each driven body (such as the rack motor of the developing rack 20) between the power supply unit 53 and the battery 55 using the switching unit 57 or the like. .

  Each driven body (also referred to as a printer engine) including the developing rack 20 and the like in the image forming apparatus 1 is driven by receiving power supply from a power supply unit 53 connected to a commercial power supply or the like during normal operation. . For example, electric power is supplied from the power supply unit 53 to the rack motor 20R, the rotational driving force of the rack motor 20R is generated, and the developing rack 20 is rotationally driven.

  On the other hand, at the time of emergency stop, power supply from the power supply unit 53 to each drive unit of each driven body is stopped, and the drive operation by the power supply unit 53 is not performed. Thereby, when an operator opens a main body cover etc. and performs maintenance work, it can avoid that each driven body malfunctions.

  However, in the image forming apparatus 1, during the emergency stop, power can be supplied from the capacitor 55 to each drive unit (not from the power supply unit 53). Therefore, even after an emergency stop, each drive unit can be driven by the electric power stored in the battery 55. The capacitor 55 accumulates regenerative energy at the time of emergency stop of each drive unit, as will be described later. The energy stored in the capacitor 55 is relatively small, and the operation duration time of the capacitor 55 is limited. . Therefore, even if a malfunction occurs, the influence of the malfunction is very limited. For example, in the case where each drive unit is driven by the energy of the battery 55 immediately after an emergency stop, when the operator opens the cover after the drive, the amount of power stored in the battery 55 has already been reduced. Therefore, normally, when the operator performs maintenance work by opening the main body cover or the like, each drive unit does not operate, or even if each drive unit operates, at least each drive unit is a capacitor. It will not continue to operate with 55 energy.

  The battery 55 converts the kinetic energy of the driven body that is rotating and moving into electrical energy and stores it. In other words, the battery 55 accumulates regenerative energy relating to the moving driven body as electric energy. For example, it is assumed that the developing rack 20 is rotating at an emergency stop operation start time T10 caused by a paper jam or the like. At this time, in the period from the emergency stop operation start time T10 to the actual stop time T11 (that is, the braking period), the rack motor 20R of the developing rack 20 converts the rotational energy (kinetic energy) of the developing rack 20 into electrical energy. Convert. Then, the converted electric energy (that is, regenerative energy) is stored in the battery 55. As the battery 55, a capacitor, a secondary battery (rechargeable battery), or the like can be used. Note that a capacitor is preferably used as the battery 55 from the viewpoint of cost.

  Then, the image forming apparatus 1 uses the electric energy stored in the capacitor 55 to perform the return operation S2 (during the emergency stop period (the period from the emergency operation start time to the operation restart time, particularly after the actual stop time). The developing rack 20 and the like can be driven even during a period in which (described later) is executed.

  Specifically, the drive control unit 110 is stored in the capacitor 55 immediately after the emergency stop (specifically, after each driven body that was in motion at the time of the emergency stop operation start actually stops). The drive part (rack motor 20R or the like) of each driven body (development rack 20 or the like) is driven using electrical energy, and the driven body is driven toward a predetermined standby position (reference position) PG1. As described above, the control unit 100 also controls a driving operation using the battery 55 as a driving source immediately after an emergency stop. During the emergency stop period, power supply from the power supply unit 53 to each drive unit is stopped, but power supply from the power supply unit 53 to the control unit 100 is continued. Therefore, even during the emergency stop period, the control unit 100 can execute various control operations (such as a control operation of a drive operation using the capacitor 55 as a drive source).

<1-2. Operation during emergency stop>
Next, an outline of the operation when the image forming apparatus 1 is in an emergency stop will be described.

In the image forming apparatus 1, an emergency stop signal is generated due to a paper jam or the like during execution of the normal operation (printing operation) S0, and the emergency stop operation is started from time T10 in response to the emergency stop signal. When,
(S1) Charging operation (storage operation) for converting regenerative energy into electric power and charging (charging) the capacitor 55;
(S2) a moving operation to approach the standby position PG1,
These operations are executed in this order.

Thereafter, when the paper jam is resolved again and an operation start instruction is accepted again at time T30,
(S3) Confirmation operation to confirm the current position,
Is done first. And if the current position is not the standby position,
(S4) Recovery operation to move to the reference position,
Is further executed.

After that (in detail after S3 or S4)
(S5) Normal operation (reprinting operation etc.),
Is further executed.

  Hereinafter, these operations will be described with reference to FIGS. 4 to 11 by taking driving of the developing rack 20 as an example. 4 to 8 are diagrams illustrating the rotation state of the developing rack 20, and FIGS. 9 to 11 are diagrams illustrating the power supply states in the operations S0, S1, and S2, respectively.

  As shown in FIG. 7, the rotational position of the developing rack 20 (the rotation angle), the home sensor 25, which is fixed at a predetermined position in the apparatus is recognized, such as by detecting the slits 29K in the developing unit 21K. Specifically, the rotation position (rotation angle) at which the sensor 25 detects the slit 29K is recognized as the origin position PG0 (see FIG. 7) related to the rotation operation of the developing rack 20. The rotation angle from the origin position PG0 is calculated by counting the number of pulses of the encoder attached to the motor 20R.

  Further, as shown in FIG. 8, a position rotated by a predetermined angle θ1 counterclockwise with respect to the above-described origin position PG0 (FIG. 7) is set as the standby position PG1.

  During normal operation, the developing rack 20 is on standby (stopped) while rotating to the standby position PG1 (FIG. 8). Then, the development rack 20 moves to the development position for each color in response to a print command, performs a development operation, a transfer operation to the photoreceptor 11, and the like, and returns to the standby position PG1 again. Thus, the standby position PG1 is a position when waiting for a print command, and the printing operation is started from this standby position PG1.

  Now, it is assumed that the developing rack 20 rotates counterclockwise (forward rotation direction) from the developing position related to the developing unit 21K in FIG. 4 during a normal printing operation. In this situation, as shown in FIG. 9, power is supplied from the power supply unit 53 to the motor 20 </ b> R of the developing rack 20.

  In such a situation, the control unit 100 detects that the paper jam or the like occurs as described above, determines that the state should be an emergency stop, the drive unit of the driven member from the power supply unit 53 (rack The power supply to the motor 20R or the like is stopped at time T10 (see also FIG. 10). The power supply from the power supply unit 53 to each drive unit remains stopped in the operations S1 and S2 after the time T10 and is resumed after the time T30 described later. Note that power supply from the power supply unit 53 to the control unit (CPU or the like) 100 is continued in the operations S1 and S2.

And according to the said electric power feeding stop from the power supply part 53 to each drive part,
(S1) Charging operation for converting regenerative energy into electric power and charging,
Is executed.

  In this operation S1, the rotational energy of the driven body that is rotating is acquired as regenerative energy (see FIG. 10).

  For example, the developing rack 20 at time T10 is the case is rotating, the rotation of the developing rack 20 in the subsequent time T11 is obtained regenerative energy in the motor 20R before stopping (Figure 5). The regenerative energy is converted into electric power and stored in the battery 55. Further, the control unit 100 calculates the stop position of the developing rack 20 at time T11 based on the count value of the encoder pulse until the stop.

Next,
(S2) Movement operation (return operation) to approach the standby position,
Will be described.

  In the return operation S2, each driven body (development rack 20, etc.) is driven (return drive) toward each reference position (standby position PG1, etc.) using the energy accumulated in the battery 55.

  This moving operation S2 is executed from time T20 immediately after the emergency stop. Time T20 is the time immediately after time T19 when all the driven bodies that were rotating at time T10 stopped. For example, when the developing rack 20 is stopped last among all the driven bodies, the time T19 is the same as the time T11. Moreover, it is preferable that the time difference between the time point T19 and the time point T20 is close to zero.

  In the moving operation S2, the drive unit (development rack 20 or the like) that was being driven at time T10 is driven again using the electric power stored in the battery 55 in the above-described operation S1 or the like (see FIG. 11). . Specifically, the image forming apparatus 1 rotates the developing rack 20 from its current position (FIG. 5) toward a predetermined standby position PG1 (FIG. 8).

  When a sufficient amount of electric power is accumulated in the battery 55, the developing rack 20 moves to the desired standby position PG1 (FIG. 8) and stops in this moving operation S2, and the current position ( In this case, information on the same as the standby position PG1) is stored in the nonvolatile memory 108 (see FIG. 1) in the control unit 100.

  On the other hand, when a sufficient amount of electric power is not stored in the battery 55, the developing rack 20 cannot reach the desired standby position PG1 in this movement operation S2, and is at a position before the desired standby position PG1. Stop (see FIG. 6). Further, information on the current position after the stop is stored in the nonvolatile memory 108.

  After that, the jammed paper or the like is removed from the image forming apparatus 1 by the operator to eliminate the paper jam and the operation resumption instruction (pressing the start key, etc.) from the operator is accepted at time T30. And

In response to the operation resumption instruction, the image forming apparatus 1 confirms that the main body cover is closed, and then changes the power state of the apparatus to the state as shown in FIG. Power supply state), and
(S3) Confirmation operation to confirm the current position,
First do.

  Specifically, the control unit 100 reads the current position stored in the nonvolatile memory 108 and confirms whether or not the current position is equal to the reference position (such as the standby position PG1).

  When the current position is equal to the reference position, no recovery operation is necessary, and a reprint operation or the like can be immediately executed.

On the other hand, if the current position is not equal to the reference position,
(S4) Recovery operation to move to the reference position,
Is executed. For example, the drive control unit 110 moves the developing rack 20 to the standby position PG1 based on the current position information stored in the nonvolatile memory 108.

  As a method for returning to the standby position PG1, there is also a method in which the developing rack 20 is once returned to the origin and then moved to the standby position PG1. Specifically, first, the developing rack 20 is rotated in a predetermined direction (for example, counterclockwise) to once search for the origin position PG0. Thereafter, the developing rack 20 is further rotated from the origin position PG0 to the standby position PG1 rotated by a predetermined angle θ1. As a result, the developing rack 20 reaches the standby position PG1. However, when such a method is used, when the current position is, for example, a position as shown in FIG. 6 (a position between the origin position PG0 and the standby position PG1), the rotation is performed almost once to search for the origin position PG0. It takes a lot of time. On the other hand, as described above, the current position after the emergency stop is stored in the non-volatile memory 108, and the position information stored in the non-volatile memory 108 is used. Since it is possible to return to PG1, a recovery operation can be easily performed.

After such a recovery operation S4, an operation to be performed after the recovery operation, that is,
(S5) Normal operation (reprinting operation etc.),
Is executed.

  According to the above operation, during an emergency stop due to a paper jam or the like, during the period after time T20 and before time T30, the regenerative electric power related to the development rack 20 is used to drive the developing rack 20 (motor 20R). Etc.) and the developing rack 20 can be moved toward the standby position. For example, when the regenerative power is sufficient, the developing rack 20 can be moved to the standby position PG1 in advance, so that the developing rack 20 is changed to the standby position PG1 in the recovery operation after the operation is resumed (after time T30). No need to move to. Therefore, the time required for the recovery operation after the operation is resumed (after time T30) can be greatly reduced. Even if the regenerative power is not sufficient, the operation toward the standby position PG1 is executed before the recovery operation (immediately after the emergency stop) and has moved in advance to a position relatively close to the standby position PG1. In the recovery operation after time T30, the time for moving to the standby position PG1 is shortened. Thus, the recovery time can be shortened.

  In addition, the power may be turned off between the operation S2 and the operation S3 according to the operation of the operator. By storing the current position immediately after the emergency stop of the driven body in the nonvolatile memory 108 as described above, when the power is temporarily turned off during the emergency stop period and then turned on again. However, the driven body can be easily moved to the reference position by the operations S3 and S4 as described above. That is, in the recovery operation after the operation is resumed, it is possible to easily move the predetermined driven body to the reference position by reading the current position stored in the nonvolatile memory.

  In the above, the current position of each driven body is not recorded in the nonvolatile memory 108 during normal operation, but is recorded in the nonvolatile memory 108 immediately after an emergency stop. That is, the current position of each driven body is not constantly updated in the nonvolatile memory 108 but is updated and stored at a limited opportunity such as immediately after an emergency stop. For this reason, the number of times the nonvolatile memory is stored becomes difficult to reach the upper limit.

  In the above description, the case where the developing rack 20 is rotating at the time T10 has been described. However, the present invention is not limited to this. For example, the same idea as described above may be applied when the photoconductor 11 is rotating at time T10. Specifically, before the rotation of the photoconductor 11 stops, regenerative energy is acquired using a photoconductor drive motor 11R (see FIG. 10) or the like, and the photoconductor 11 is used using the regenerative energy or the like. The photosensitive member 11 may be rotated to a predetermined standby position. In particular, in the case where the rotation phase of the photoconductor 11 is adjusted by making the photoconductor 11 stand by at a predetermined standby position and the influence of the rotation unevenness caused by the eccentricity of the photoconductor 11 is suppressed, the above-described concept is used. It is preferable to apply.

  When a plurality of the driven member (e.g. both the development rack 20 and the photosensitive member 11) has been driven at time T10, like each for all the plurality of the driven body performs the same operation as described above You can do it.

  Moreover, in the above, although the case where only the to-be-driven body from which the regenerative energy is acquired is moved to the standby position is illustrated, the present invention is not limited to this. For example, not only the driven body that is the acquisition target of the regenerative energy is moved to the standby position, but each driven body other than the acquisition target of the regenerative energy may be moved to the standby position. As the driven body other than the target for obtaining the regenerative energy, for example, a driving mechanism (solenoid or the like) related to the pressure contact / separation operation of the transfer roller 32, that is, a pressure contact / separation mechanism of the transfer device is exemplified. Alternatively, a driving mechanism (solenoid or the like) related to the pressure contact / separation operation of the fixing device 45, that is, a pressure contact / separation mechanism or the like of the fixing device is also exemplified.

<2. Second Embodiment>
In this 2nd Embodiment, the case where movement operation | movement S2 is performed not only using the electrical energy converted from the kinetic energy but also using the electrical energy converted from the thermal energy is illustrated. The second embodiment is a modification of the first embodiment, and the following description will focus on differences from the first embodiment.

  FIG. 12 is a diagram illustrating an image forming apparatus 1 (also referred to as 1B) according to the second embodiment. In the image forming apparatus 1B according to the second embodiment, as shown in FIG. 12, a thermoelectric conversion element 48 such as a Peltier element is disposed in the vicinity of the fixing device 45 (heat generating portion). Then, using this thermoelectric conversion element 48, heat (thermal energy) generated in the fixing device 45 is converted into electric power (electric energy), and the converted electric energy is also stored in the capacitor 55 (see FIG. 13). Note that, similarly to the first embodiment, the battery 55 also stores regenerative energy (electric energy after conversion) by the developing rack 20.

  In the moving operation S2, the predetermined driven body (development rack 20 or the like) is driven based on the electric power generated using the thermoelectric conversion element or the like. Specifically, the rack motor 20R and the like are driven immediately after an emergency stop using the electrical energy accumulated in the battery 55 (both the electrical energy due to the regenerative operation and the electrical energy due to thermoelectric conversion), so that the developing rack 20 and the like are It is rotated.

  Also by such an aspect, it is possible to obtain the same effect as that of the first embodiment. Further, immediately after emergency stop, because the electric energy generated by the thermoelectric conversion element 48 be used given the driven member (developing rack 20, etc.) is driven, the predetermined driven member a predetermined reference position ( It is easy to reach the standby position PG1 or the like.

<3. Third Embodiment>
The third embodiment is a modification of the first embodiment. Hereinafter, the difference from the first embodiment will be mainly described.

  In the third embodiment, a mode in which an operation of returning a plurality of driven bodies to their respective reference positions (standby positions) using the regenerative energy stored in the battery 55 during an emergency stop will be described. . However, in this third embodiment, not all the driven bodies are always driven to return at the time of emergency stop, but from among a plurality of driven bodies in consideration of the total amount of regenerative energy stored in the capacitor 55. A mode in which only the selected drive target is driven to return will be described. According to such an aspect, it is possible to further shorten the time required for the recovery operation.

  FIG. 14 is a flowchart illustrating an operation according to the third embodiment, and FIG. 15 is a diagram illustrating detailed functional blocks of the control unit 100 (100C) according to the third embodiment.

  As illustrated in FIG. 15, the control unit 100 </ b> C includes a power storage amount calculation unit 111, a required power amount calculation unit 113, a return time calculation unit 115, a determination unit 117, and a drive control unit 110. Each of these processing units is functionally realized by executing a predetermined program in the CPU of the control unit 100C.

  The power storage amount calculation unit 111 calculates a power storage amount PR that is the amount of power stored in the battery 55 during an emergency stop.

  The required power amount calculation unit 113 calculates each required power amount, which is a power amount for returning the plurality of driven bodies immediately after the emergency stop to the respective reference positions.

  The return time calculation unit 115 calculates each required return time required for returning the plurality of driven bodies immediately after the emergency stop from the respective current positions to the respective reference positions.

  The determination unit 117 determines a drive target to be driven immediately after an emergency stop among a plurality of driven bodies, based on the storage amount PR, each required power amount PEi, and each required return time TEi.

  Immediately after the emergency stop, the drive control unit 110 uses the regenerative energy accumulated in the capacitor 55 to direct the driven body to be driven, which is determined by the determination unit 117, among the plurality of driven bodies toward the reference position. Drive.

  In the third embodiment, after the normal operation S0 and charging operation S1 of similar to the above is performed, the moving operation S2 shown in FIG. 14 (S2c) is performed under control of the control unit 100C.

  Specifically, as shown in FIG. 14, first, in step S21, the regenerative energy PRi obtained by each of the plurality of driven bodies (development rack 20, etc.) in the above-described charging operation S1 is calculated.

  For example, the regenerative energy (electric energy) PR1 related to the developing rack 20 among the plurality of driven bodies is obtained based on the following equation (1), for example. In the expression (1), it is considered that the regenerative energy PR1 changes according to the rotation state of the developing rack 20 (specifically, the motor 20R) immediately before stopping.

PR1 = P1 × TR1 (1)
Here, the value P1 is a power value (average value) of regenerative power according to the rotation state (specifically, the rotation command value and the acceleration / deceleration state) immediately before the emergency stop. The value P1 is obtained in advance based on experiments or the like, and is stored in advance in the data table TL11 (FIG. 16). FIG. 16 is a diagram illustrating a data table TL11 in which a power value P1 of regenerative power related to the developing rack 20 is stored.

  For example, in FIG. 16, when the rotation command value for the motor 20R is 400 (rpm (per rotation)), the acceleration / deceleration status (motor status) is “accelerating”, “steady rotating”, and Each value of 5 W (Watt), 15 W (Watt), and 10 W (Watt) is stored as the value P <b> 1 depending on which of “decelerated”. Similarly, when the rotation command value for the motor 20R is 800 (rpm (per rotation)), depending on the acceleration / deceleration status (“accelerating”, “steady rotating”, and “decelerating”), Each value of 8 W (Watt), 30 W (Watt), and 20 W (Watt) is stored as a value P1. Strictly speaking, the generated regenerative power varies depending on the point in time within the acceleration period TA (or deceleration period TC) (see FIG. 17), but it is simplified here. Therefore, during acceleration and deceleration, it is considered that a fixed regenerative power is acquired without depending on which time point in the acceleration / deceleration period.

  The value TR1 is the time from the emergency stop start time (braking start time) T10 to the stop time T11. Specifically, the time TR1 required for stopping is calculated by calculating the speed V10 of the driven body at the braking start time T10 and taking into account the deceleration (negative acceleration) of the driven body during regenerative braking. Is done. More specifically, whether the braking start time point T10 is a time point within the acceleration period TA, a time point within the constant speed period TB, or a time point within the deceleration period TC in the normal acceleration / deceleration pattern (see FIG. 17). Further, the speed V10 of the driven body at the braking start time T10 is calculated by determining which time point within the periods TA and TC the braking start time T10 is. And the time from the calculated speed V10 to a stop is calculated based on the deceleration acceleration (negative acceleration) of the driven body at the time of regenerative braking. In this way, the value TR1 is calculated. In addition, it is preferable to previously store the time from each speed V10 to the stop in the data table.

  For example, when the value P1 is "30 W (Watt)" is a and the value TR1 is "2 seconds" is, regenerative energy PR1 is calculated as 60 (watt seconds) (= 30 × 2).

  Similarly, with respect to other driven bodies, the respective regenerative energy PRi is calculated based on the following equation (2).

PRi = Pi × TRi (2)
Here, each value Pi is a power value of regenerative power corresponding to the driving state of each driven body immediately before the emergency stop. The value TRi is the time from the emergency stop start point (braking start) to the actual stop point of each driven body. FIG. 19 is a diagram showing a data table TL12 in which the power value P2 of regenerative power related to the photoconductor 11 is stored. The power value P2 of the regenerative power related to the photoconductor 11 is determined based on the data table TL12.

  And the total value of each regenerative energy PRi of these several to-be-driven bodies is calculated as total regenerative energy PR.

  Next, in step S22, for each of the plurality of the driven body, the time required until the return to the reference position (standby position) (the required recovery time) TEi is calculated.

  For example, for the developing rack 20, the time TE1 required to return from the current position immediately after the emergency stop (time T11) to the reference position (standby position PG1) is calculated. This value TE1 may be calculated based on the distance D1 from the current position to the standby position PG1 and the average moving speed V1 (TE1 = D1 / V1). Note that the value TE1 may be calculated more accurately based on acceleration, deceleration, steady speed, and the like in the acceleration / deceleration pattern for return operation. Further, from the viewpoint of speeding up the calculation process, a data table showing the relationship between the distance D1 and the required return time TE1 during the return operation is created in advance, and the required return time is calculated using the data table. It is preferable.

  Similarly, each required return time TEi is calculated for other driven bodies.

  Further, in this step S22, for each of the plurality of driven bodies, the energy (required electric energy) PEi required to return each driven body from each current position to each reference position is also calculated. The value PEi is expressed by the following equation (3).

PEi = Ui × TEi (3)
Here, the value Ui is power (average value) for driving each driven body (development rack 20 or the like). Strictly speaking, the value Ui is different for each distance D1 from the current position to the standby position PG1, but here the value Ui is assumed to be constant for simplicity.

  FIG. 18 is a diagram showing a data table TL30 in which required power Ui for each driven body is stored.

  In the data table TL30 of FIG. 18, for example, it is shown that 20 W (watts) is required as the required power Ui for returning the developing rack 20 toward the standby position PG1. If the value TEi is calculated as “1.5 seconds”, the required power PEi for returning the developing rack 20 to the standby position PG1 is 30 (watt seconds) (= 20 × 1.5). Is calculated as

  Similarly, the data table TL30 indicates that 10 W (watts) is required as the required power Ui for returning the photosensitive member 11 toward the reference position. Assuming that the value TEi is calculated as “1.0 second”, the required electric energy PEi for returning the photosensitive member 11 to its reference position is 10 (watt seconds) (= 10 × 1.0). Calculated.

  In the next step S23, the driving target to be driven immediately after the emergency stop is determined among the plurality of driven bodies.

  For example, when it is possible to return all of the plurality of driven bodies to the reference position using the energy stored in the capacitor 55, all of the plurality of driven bodies are determined as driving targets. The Specifically, when the total value of regenerative energy generated by each driven body (the amount of power stored in the battery 55) PR is greater than the total value PE (total power requirement) of each PEi, All of the driven bodies are determined as “driving targets”.

  On the other hand, if this is not the case, the driven body to be driven is selected as the “driven object” from the plurality of driven bodies based on the priority order determined depending on each required return time TEi. It is determined. Here, it is assumed that a relatively high priority is given to the driven body ACj having a relatively long required return time TEi.

  Specifically, first, among the plurality of driven bodies ACj, the driven body AC1 having the longest (required) return time TEi is selected as the target driven body, and the required power amount of the target driven body AC1 PEi is added to the total required power PT. When the total required power amount PT is less than or equal to the stored electricity amount PR, the target driven body AC1 is determined as a driving target.

  Next, of the plurality of driven bodies ACj, the driven body AC2 having the second largest required return time TEi is selected as the target driven body, and the required power amount PEi of the target driven body AC2 is the total required power. Further added to the quantity PT. When the total required power amount PT after the addition is equal to or less than the charged amount PR, the target driven body AC2 is added to the drive target. That is, the target driven body AC2 is further determined as the driving target together with the determined driven body AC1. On the other hand, when the total required power amount PT is larger than the charged amount PR, the target driven body AC2 is excluded from the driving target.

  The driving target is determined by repeating the same operation. That is, N (one or two or more) driven bodies are selected as driving objects in accordance with the above-described priority order so that the total required power amount PT does not exceed the charged amount PR. . Here, the total required power amount PT is a total value PT of required power amounts PEi for returning N (N is a natural number) driven bodies to their respective reference positions.

  As described above, N (N) selected according to the priority order corresponding to each required return time TEi among the plurality of driven bodies ACj based on the storage amount PR, each required power amount PEi, and the required return time TEi. Is a natural number), it is determined that it is possible to return the driven bodies to their respective reference positions, and the N driven bodies are determined as “driving targets”.

  Thereafter, in step S <b> 24, the image forming apparatus 1 stores, in the nonvolatile memory 108, the current position of the driven body other than the driving target among all the driven bodies.

  In step S25, the image forming apparatus 1 drives the driven body to be driven (selected in step S23) among all the driven bodies. Thereafter, the image forming apparatus 1 stores the current position after the return operation of the driven body to be driven among all the driven bodies in the nonvolatile memory 108.

  Here, when the determination operation in step S23 is correct as a result, each driven body to be driven returns appropriately to each reference position, but the determination operation is not correct as a result. In other words, each driven body to be driven cannot reach each reference position and stops before the reference position. In any case, the current position after stopping each driven body to be driven is stored in the nonvolatile memory 108 (step S26).

  Further, as in the first embodiment, when an operation resumption instruction is accepted by the operator, the operations S3, S4, and S5 as described above are executed after time T30.

  According to the above aspect, it is possible to obtain the same effect as that of the first embodiment. In particular, at the time of an emergency stop, the driven body having a relatively large required return time TEi is preferentially driven and returned to the reference position using the energy of the battery 55, so that the recovery operation after the restart of the operation can be performed. It is possible to shorten the time required. That is, the recovery time can be further shortened by intensively driving the selected driven body back.

  For example, it is assumed that the required return times of all (three) driven bodies AC1, AC2, and AC3 are 3 seconds, 1 second, and 1 second, respectively. At this time, if the driven body AC1 having the longest required return time is returned to the reference position in advance, the remaining two driven bodies AC2 and AC3 are returned to the reference position in a maximum of 1 second in the recovery operation S4. It is possible. In other words, it is possible to shorten the operation time during the recovery operation by intensively driving a driven body having a relatively large required recovery time among a plurality of driven bodies using the storage amount PR. is there. Thus, an efficient recovery operation can be realized.

  Note that when a specific condition (such as a required return time of one driven body is significantly longer than that of a plurality of other driven bodies) is satisfied, the recovery time is reduced by such a selective return operation. It can be shortened well. However, the recovery time when the specific condition is not satisfied may be longer than the recovery time when all the driven bodies are driven to return. In order to avoid such a situation, the return drive operation is not performed according to the selection result in the operation of selecting the drive target from among all the driven bodies, but in a manner according to the following modified example. May be performed. Specifically, the expected value RT1 of the recovery time when the return drive is performed according to the selection result and the expected value RT0 of the recovery time when all the driven bodies are driven to return without following the selection result are compared. Then, it may be determined which return drive operation is performed according to the comparison result. Specifically, the return drive corresponding to the smaller value of the expected values RT0 and RT1 may be executed.

<4. Fourth Embodiment>
The fourth embodiment is a modification of the third embodiment. Hereinafter, the difference from the third embodiment will be mainly described.

  In the fourth embodiment, as in the second embodiment (see FIG. 12), a thermoelectric conversion element (such as a Peltier element) 48 is disposed in the vicinity of the fixing device 45, and the thermoelectric conversion element 48 causes the fixing device 45 to Heat is converted into electrical energy. However, the converted energy is stored in a capacitor (here, a capacitor) 56 (FIG. 20) different from the capacitor 55. In the fourth embodiment, the voltage across the battery 56 (capacitor) 56 is monitored to calculate the charge amount PR0 of the battery 56.

  The power storage amount PR0 is also added to the power storage amount PR, and the same operation as in the third embodiment is executed.

  Specifically, in the fourth embodiment, operations corresponding to steps S21 and S23 in FIG. 14 are different from those in the third embodiment.

  Specifically, in step S21, not only the regenerative energy value PRi is calculated, but also the electric energy value PR0 converted and generated by the thermoelectric conversion element 48 is calculated. FIG. 20 is an electric circuit diagram relating to the thermoelectric conversion element 48. Using the electric circuit as shown in FIG. 20, the thermoelectric conversion element 48 converts thermal energy into electric energy and stores it in a capacitor (here, a capacitor) 56. In step S21, the storage amount calculation unit 111 of the control unit 100 (100D) monitors the voltage (measured value) of the voltage across the capacitor 56 (specifically, the voltage across the electrical resistance connected in parallel to the capacitor 56) V2. ) To calculate the electrical energy PR0 stored in the battery 56. The relationship between voltage V2 and electrical energy PR0 is preferably calculated in advance and stored in a data table.

  In step S23, the total value of each regenerative energy value PRi and the electric energy value PR0 is adopted as the charged amount PR, and the same determination operation and the like as in the third embodiment are performed.

  According to such an aspect, it is possible to return more driven bodies to the respective reference positions immediately after an emergency stop using the electric energy generated by the thermoelectric conversion element 48. Therefore, the recovery time can be further shortened.

  In particular, during an emergency stop, the driven body having a relatively large required return time TEi is preferentially driven and returned to the reference position using the energy of the capacitors 55 and 56, so that the recovery after resuming the operation is performed. It is possible to reduce the time required for the operation.

<5. Modified example>
Although the embodiments of the present invention have been described above, the present invention is not limited to the contents described above.

  For example, in the third embodiment, the case where the charged amount PR of the battery 55 is calculated based on the formula (2) or the like is illustrated, but the present invention is not limited to this. Specifically, similarly to the case where the voltage across the capacitor 56 is monitored by calculating the voltage across the capacitor 56 in the fourth embodiment, a capacitor is adopted as the capacitor 55 and the voltage across the capacitor 55 is used. May be monitored, and the amount of stored electricity (regenerative energy) PR accumulated in the battery 55 may be calculated. However, it is not necessary to provide such a monitoring circuit by calculating the storage amount PR based on the arithmetic processing using the above formula (2) or the like.

  In each of the above embodiments, the standby position is mainly exemplified as the “reference position” of each driven body. However, the present invention is not limited to this, and may be other positions such as an origin position.

  In each of the above embodiments, a four-cycle full-color electrophotographic apparatus (electrophotographic image forming apparatus) has been exemplified, but the present invention is not limited to this. For example, the above concept may be applied to a tandem full-color electrophotographic apparatus (electrophotographic image forming apparatus). Specifically, each driven body such as a plurality of photosensitive drums, a plurality of primary transfer units, and a secondary transfer unit may perform a return operation similar to the above during an emergency stop.

  In each of the above embodiments, an image forming apparatus having only a printing function has been illustrated, but the present invention is not limited to this. For example, the above concept is applied to an image forming apparatus such as an MFP (Multi Function Peripheral) having a plurality of functions such as a scan function, a FAX function, and a copy function as well as a print function. Also good.

  Moreover, in each said embodiment, although illustrated about the case where the regenerative energy of the to-be-driven body in a printing mechanism is utilized, it is not limited to this. For example, the above concept may be applied to a technique for returning the moving unit in the scanner unit to the reference position.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 11 Photoconductor 20 Developing rack 20R Rack motor 21, 21Y, 21M, 21C, 21K Developing unit 25 Sensor 28 Toner storage part 29K Slit 31 Intermediate transfer belt 32 Secondary transfer roller 33 Driving roller 45 Fixing device 48 Thermoelectric conversion Element 53 Power supply unit 55, 56 Capacitor 108 Non-volatile memory

Claims (12)

An image forming apparatus,
A predetermined driven body;
Power storage means for storing regenerative energy related to the predetermined driven body at the time of emergency stop as electric energy;
Immediately after the emergency stop, using the energy stored in the power storage means, drive control means for returning the predetermined driven body toward a predetermined reference position; and
An image forming apparatus comprising: The image forming apparatus according to claim 1.
A nonvolatile memory for storing a current position of the predetermined driven body after the return driving;
Further comprising
The drive control means moves the predetermined driven body to the predetermined reference position based on the current position stored in the nonvolatile memory when the operation is resumed after the emergency stop. Image forming apparatus. The image forming apparatus according to claim 1, wherein:
Thermoelectric conversion means for converting thermal energy of a predetermined heat generating part into electrical energy,
Further comprising
The image forming apparatus, wherein the control unit drives the driven body using the electric energy generated by the thermoelectric conversion unit immediately after the emergency stop. The image forming apparatus according to any one of claims 1 to 3,
2. The image forming apparatus according to claim 1, wherein the predetermined driven body is a rotary developing rack provided in a four-cycle electrophotographic image forming apparatus. The image forming apparatus according to any one of claims 1 to 3,
The image forming apparatus, wherein the predetermined driven body is a photosensitive drum. The image forming apparatus according to any one of claims 1 to 5,
A second driven body other than the first driven body which is the predetermined driven body;
Further comprising
The predetermined reference position is a reference position of the first driven body;
The control means drives the first driven body and the second driven body using the electric power stored in the power storage means during the emergency stop, and the first driven body The image forming apparatus, wherein the second driven body is driven toward the first reference position and the second driven body is driven toward the reference position of the second driven body. The image forming apparatus according to claim 6.
The image forming apparatus according to claim 2, wherein the second driven body is a press-contact / separation mechanism of a fixing device. The image forming apparatus according to claim 6.
2. The image forming apparatus according to claim 1, wherein the second driven body is a pressure contact / separation mechanism of a transfer device. A plurality of driven bodies;
Power storage means for storing regenerative energy related to the plurality of driven bodies at the time of emergency stop as electric energy;
A storage amount calculation means for calculating a storage amount that is an amount of power stored in the storage means;
Required power amount calculating means for calculating each required power amount that is an amount of power for returning the plurality of driven bodies to the respective reference positions;
Return time calculating means for calculating each required return time required for returning the plurality of driven bodies from the respective current positions to the respective reference positions;
Determining means for determining a drive target to be driven immediately after the emergency stop among the plurality of driven bodies, based on the power storage amount, each required power amount, and each required return time;
Immediately after the emergency stop, using the regenerative energy accumulated in the power storage means, the driven body to be driven determined by the determining means among the plurality of driven bodies is driven toward the reference position. Drive control means;
An image forming apparatus comprising: The image forming apparatus according to claim 9.
The determining means selects N driven bodies selected from the plurality of driven bodies according to a priority order corresponding to each required return time based on the power storage amount and the required power amounts. An image forming apparatus, wherein when it is determined that it is possible to return to a reference position, the N driven bodies are determined as the driving objects. The image forming apparatus according to claim 9 or 10, wherein:
Nonvolatile storage means for storing each current position immediately after an emergency stop of the plurality of driven bodies;
An image forming apparatus further comprising: 12. The image forming apparatus according to claim 9, wherein
Thermoelectric conversion means for converting thermal energy of a predetermined heat generating part into electrical energy,
Further comprising
The image forming apparatus, wherein the storage amount calculation unit calculates a value including the amount of power stored in the storage unit by the thermoelectric conversion unit as the storage amount.

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