JP7326902B2 - DRIVE CONTROL DEVICE, IMAGE FORMING APPARATUS AND DRIVE CONTROL METHOD - Google Patents

Description

The present invention relates to a drive control device, an image forming apparatus and a drive control method.

2. Description of the Related Art Conventionally, there is a technique of operating a drive unit such as a motor to transmit force to an object (conveying medium) to move it. At this time, if the conveying speed changes abruptly, vibrations or the like may occur in response to changes in acceleration, which may pose a problem. Therefore, there is a technique of determining the change time of the conveying speed and also defining the change pattern of sequentially changing the conveying speed so that the change of the acceleration does not become too large (Patent Documents 1 and 2).

JP-A-2002-259957 JP-A-2004-129443

However, depending on the condition of the transported medium, etc., an unexpected load may occur, and the operation of the driving unit may deviate from normal changes. In such a case, there is a problem that the conventional technology cannot cope with it.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a drive control device, an image forming apparatus, and a drive control method that are capable of more flexibly and reliably controlling the conveying speed.

In order to achieve the above object, the invention according to claim 1,
a storage unit that stores operating speed information of a driving unit that generates a driving force applied to a predetermined object;
a control unit that controls the operating speed of the driving unit based on the operating speed information;
an acquisition unit that acquires a detection result of a load detection unit that detects the load of the drive unit;
with
The control unit changes the operating speed information to change the operating speed when a detection result indicating an abnormality of the load is acquired ,
decreasing the absolute value of the acceleration associated with the change in the operating speed when a detection result indicating that the load is abnormal is acquired during the change in the operating speed;
stopping the reduction of the absolute value of the acceleration and temporarily increasing the absolute value when a detection result indicating that the abnormality of the load has been resolved is acquired;
An operating speed of the driving unit that changes sequentially due to a temporary increase in the absolute value of the acceleration, and an operating speed according to the change determined by the operating speed information before acquisition of a detection result indicating an abnormality in the load. terminating the temporary rise when equal to the assumed value of
When the detection result indicating that the load abnormality has been resolved is obtained, the driving unit is operated within a period in which the operation speed is scheduled to be changed according to the operation speed information before the detection result indicating the load abnormality is obtained. Determine the temporary increase amount of the absolute value of the acceleration so that the operating speed of and the assumed value are equal
This drive control device is characterized by:

Further, the invention according to claim 2 is the drive control device according to claim 1,
the operation speed information includes an array of speed index values related to the operation speed of the drive unit;
When changing the operating speed of the driving unit, the control unit sequentially changes the operating speed in accordance with the arrangement order of the speed index values, and a detection result indicating an abnormality of the load is detected during the change of the operating speed. When obtained, the absolute value of the acceleration associated with the change in the motion speed is decreased.

Further, the invention according to claim 3 is the drive control device according to claim 1 or 2,
The control unit is characterized in that, when a detection result indicating an abnormality in the load is acquired during the change of the operating speed, the changing of the operating speed is interrupted.

Further, the invention according to claim 4 is the drive control device according to any one of claims 1 to 3 ,
The drive section may include a first drive section and a second drive section that generate the drive force applied to the same target.

Further, the invention according to claim 5 is the drive control device according to claim 4 ,
The second driving section is characterized by transmitting the driving force to the same transmission shaft as the first driving section.

Further, the invention according to claim 6 is the drive control device according to claim 5 ,
The control unit is capable of adjusting the driving force transmitted from the second driving unit to the transmission shaft,
The driving force of the second driving section is increased when a detection result indicating an abnormality of the load is obtained.

Further, the invention according to claim 7 is the drive control device according to claim 6 ,
The control unit equalizes the operation speed of the first driving unit and an assumed value of the operation speed according to the change determined by the operation speed information before acquisition of the detection result indicating the abnormality of the load. It is characterized in that the increase in the driving force is terminated when the driving force becomes.

Further, the invention according to claim 8 is the drive control device according to claim 4 ,
Said 1st drive part and said 2nd drive part are characterized by applying driving force with respect to said object individually.

Further, the invention according to claim 9 is the drive control device according to claim 8 ,
The control section may control the operating speed of the first driving section and the operating speed of the second driving section based on the same operating speed information.

Further, the invention according to claim 10 is the drive control device according to claim 8 or 9 ,
The acquisition unit acquires detection results of an operation amount detection unit that detects an operation amount at a predetermined position corresponding to each operation of the first drive unit and the second drive unit,
When the movement amount detection section detects a change in the movement speed of one of the first drive section and the second drive section, the control section changes the movement speed information to a magnitude corresponding to the change. The operation speed of the first drive unit and the operation speed of the second drive unit are adjusted to match each other.

Further, the invention according to claim 11 is the drive control device according to claim 10 ,
The motion amount detection unit is characterized by having an encoder.

Further, the invention according to claim 12 is the drive control device according to any one of claims 8 to 11 ,
The acquisition unit acquires a detection result of a target detection unit that detects a movement state of the target in a predetermined direction,
The first driving section and the second driving section apply a driving force to the object at positions aligned in a direction perpendicular to the predetermined direction, and move the object in the predetermined direction according to the operating speed. move at the specified speed,
The control unit identifies an inclination of the object with respect to the predetermined direction based on the detection result of the object detection unit, and controls the first driving unit and the second driving unit so that the identified inclination is removed. It is characterized by correcting the operation speed of at least one of the parts.

Further, the invention according to claim 13 is the drive control device according to claim 12 ,
The target detection unit has a plurality of sensors capable of detecting the presence or absence of the target,
The sensors are arranged in parallel in a direction perpendicular to the predetermined direction,
The controller is characterized in that the tilt is specified according to a difference in detection timing of the object by the plurality of sensors.

Further, the invention according to claim 14 is the drive control device according to claim 13 ,
The plurality of sensors are optical sensors.

Further, the invention according to claim 15 is the drive control device according to any one of claims 4 to 14 ,
The load detection section measures a current supplied to the second drive section.

Further, the invention according to claim 16 is the drive control device according to any one of claims 4 to 15 ,
The first driving section and the second driving section are characterized by having rotary motors.

Further, the invention according to claim 17 is the drive control device according to claim 16 ,
The second driving section is characterized by having a brushless motor.

Further, the invention according to claim 18 is the drive control device according to claim 16 ,
The second drive section has a stepping motor.

Further, the invention according to claim 19 ,
a driving unit that produces a force to be transmitted to a predetermined target;
a load detection unit that detects the load of the driving unit;
A drive control device according to any one of claims 1 to 18 ;
a transport section comprising
an image forming operation unit that forms an image on the medium conveyed by the conveying unit;
An image forming apparatus comprising:

Further, the invention according to claim 20,
A drive control method for a drive unit by a drive control device having a storage unit for storing operating speed information of the drive unit that generates a driving force applied to a predetermined object ,
a control step of controlling the operating speed of the drive unit based on the operating speed information;
an acquisition step of acquiring a detection result of a load detection unit that detects the load of the driving unit;
including
In the control step, when a detection result indicating an abnormality of the load is acquired, the operating speed information is changed to change the operating speed ,
decreasing the absolute value of the acceleration associated with the change in the operating speed when a detection result indicating that the load is abnormal is acquired during the change in the operating speed;
stopping the reduction of the absolute value of the acceleration and temporarily increasing the absolute value when a detection result indicating that the abnormality of the load has been resolved is acquired;
An operating speed of the driving unit that changes sequentially due to a temporary increase in the absolute value of the acceleration, and an operating speed according to the change determined by the operating speed information before acquisition of a detection result indicating an abnormality in the load. terminating the temporary rise when equal to the assumed value of
When the detection result indicating that the load abnormality has been resolved is obtained, the driving unit is operated within a period in which the operation speed is scheduled to be changed according to the operation speed information before the detection result indicating the load abnormality is obtained. Determine the temporary increase amount of the absolute value of the acceleration so that the operating speed of and the assumed value are equal
It is characterized by

ADVANTAGE OF THE INVENTION According to this invention, there exists an effect that a conveyance speed can be controlled more flexibly and reliably.

1 is a block diagram showing the functional configuration of an image forming apparatus according to an embodiment; FIG. FIG. 3 is a schematic diagram illustrating power transmission from a drive unit to a medium to be conveyed; 3 is a block diagram for explaining the functional configuration of a medium conveying unit; FIG. FIG. 5 is a diagram for explaining speed changes of a stepping motor in the image forming apparatus; 4 is a chart showing examples of a velocity table and an acceleration table; 4 is a chart showing an example of acceleration/deceleration settings set in a register; FIG. 11 is a chart showing an example of rewriting a velocity table and an acceleration table; FIG. It is a figure explaining abnormality of a speed change. 4 is a flowchart showing a control procedure of acceleration/deceleration control processing; 4 is a flow chart showing a control procedure of an abnormality handling control process called in the acceleration/deceleration control process; It is a schematic diagram explaining the modification of power transmission from a drive part to a conveying medium. FIG. 11 is a block diagram showing the functional configuration of an image forming apparatus according to a modified example; 9 is a flowchart of speed adjustment processing in the image forming apparatus of Modification 1; FIG. 11 is a block diagram showing the functional configuration of an image forming apparatus according to Modification 2;

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing the functional configuration of an image forming apparatus 1 according to an embodiment of the invention.

The image forming apparatus 1 is, for example, a multifunction machine having a scanning (reading) function, a copying (copying) function, and a printing (image forming) function. The image forming apparatus 1 includes a control unit 11, an image reading unit 12, a forming operation unit 13 (image forming operation unit), a transport unit 14, a storage unit 15, an operation reception unit 16, a display unit 17, A communication unit 18, a bus 19, and the like are provided.

The control unit 11 controls overall operations of the image forming apparatus 1 and causes each unit to perform appropriate operations. The control unit 11 includes a CPU 111, a RAM 112, a storage unit 113, and the like. The CPU 111 performs arithmetic processing and performs various control operations. The RAM 112 provides the CPU 111 with working memory space.

The storage unit 113 stores various setting data and programs related to control operations of the control unit 11 . The setting data includes data that forms the basis of a velocity table 1411a and an acceleration table 1411b, which will be described later. The storage unit 113 has a read-only ROM, a non-volatile memory such as a readable/writable flash memory, or a combination thereof.

The image reading unit 12 has an imaging unit (scanner) and the like, reads a document placed on a reading surface, and converts it into image data. The imaging unit has a configuration capable of reading pixel values in three wavelength bands (colors) of, for example, R (red), G (green), and B (blue), and generates image data each having a predetermined resolution. The generated image data is stored in the storage unit 15 or the like.

The forming operation unit 13 is an engine that forms an image on a recording medium (such as paper) based on image data to be formed. Although not particularly limited, the forming operation unit 13 is an electronic device that forms an image by fixing toner of each color of C (cyan), M (magenta), Y (yellow), and K (black) on a recording medium. It has a photographic configuration.

The conveying unit 14 processes the document read by the image reading unit 12 and the recording medium on which the image is formed by the forming operation unit 13 (collectively referred to as a conveying medium (predetermined object in this embodiment)), etc., at appropriate timing and speed. transport with The transport unit 14 has a medium transport unit 140 that transports a recording medium on which an image is formed by the forming operation unit 13 . The medium transport unit 140 includes a drive unit 143, a drive signal output unit 142 that operates the drive unit, a control unit 141 (drive control device) that controls the output of the drive signal from the drive signal output unit 142, and a load detector. 144 and the like. Further, the transport unit 14 may have a document transport unit that transports a document to be read, separately from the medium transport unit 140 .

The driving section 143 has a stepping motor 143a (first driving section) and a brushless motor 143b (second driving section). The driving unit 143 generates a driving force according to the rotation operation of each motor (rotating motor), and directly or indirectly applies this driving force to the medium to be conveyed to move the medium in a predetermined direction. The drive signal output section 142 has a first signal output section 142a that outputs a drive signal to the stepping motor 143a and a second signal output section 142b that outputs a drive signal to the brushless motor 143b.

The drive signal output unit 142 is a driver circuit (motor driver) that outputs a signal in which the polarity of the voltage applied to the stator is changed so as to change the polarity and phase of the stator according to the rotation of the rotor of each motor of the drive unit 143. have The first signal output unit 142a outputs a signal to the stepping motor 143a such that the polarity of a predetermined unit angle (for example, 180 degrees) changes stepwise according to the pulse signal. The second signal output unit 142b supplies the brushless motor 143b with the current direction and voltage ( A signal is output by changing the duty ratio of PWM control (Pulse Width Modulation). These switching intervals are respectively performed according to the input of the drive control signal from the control section 141 . The content of the control signal from the control unit 141 will be described later.

FIG. 2 is a schematic diagram illustrating power transmission from the drive unit 143 to the medium to be conveyed. The rotating shaft 143 a 1 of the stepping motor 143 a and the rotating shaft 143 b 1 of the brushless motor 143 b are connected to the same transmission shaft 201 . A roller 202 is fixed to the transmission shaft 201 , and the roller 202 rotates as the transmission shaft 201 rotates. The rotation directions and rotation ratios of the rotating shafts 143a1 and 143b1, the transmission shaft 201, and the rollers 202 may be different. may be The rotating surface of the roller 202 contacts the conveying medium and causes the conveying medium to move as the roller 202 rotates. That is, here, the stepping motor 143a and the brushless motor 143b jointly apply a driving force to the same conveying medium (object) through the same transmission shaft 201 to move it. Here, the stepping motor 143a mainly outputs driving force related to medium movement, and the brushless motor 143b operates to support the driving force of the stepping motor 143a. That is, the second signal output section 142b can be adjusted so as to increase the amplitude (driving force) of the voltage change according to the switching of the duty ratio (increase the maximum duty ratio) as necessary. This driving force may be changed to a different magnitude depending on the type and/or the rotation speed of the medium to be conveyed, as well as in the case of a load abnormality, which will be described later.

The load detection unit 144 detects the load associated with the rotation of the transmission shaft by the stepping motor 143 a or the brushless motor 143 b and outputs it to the control unit 141 . Here, for example, the load detection unit 144 measures the current flowing through the brushless motor 143b when the brushless motor 143b is in operation.

The storage unit 15 stores image data to be formed, image data read by the image reading unit 12, and the like. The storage unit 15 includes one or more of readable and writable storage media such as volatile memory such as DRAM, HDD (Hard Disk Drive), SSD (Solid State Drive), and flash memory.

The operation reception unit 16 includes operation keys, a touch sensor integrated with the display unit 17, and the like. The operation reception unit 16 outputs an operation signal to the control unit 11 in response to a pressing operation of an operation key and a touch operation to the display of the display unit 17 from the outside (mainly by a user).

The display unit 17 can display an operation reception screen, a status, and the like according to a control signal from the control unit 11 . The display unit 17 is not particularly limited, but for example, a liquid crystal display (LCD) that performs dot matrix display is used.

The communication unit 18 is an interface for communicating with a server or the like on a network according to instructions from the control unit 11. For example, the communication unit 18 is a network card for communication via LAN (TCP/IP, etc.), or a wireless LAN (IEEE802 .11n, etc.). The communication unit 18 receives image data to be formed and setting data related to print jobs from external devices such as other computers and print servers, and outputs status signals and the like.

Next, the configuration of the transport section 14 of this embodiment will be described.
The configuration of the medium conveying unit 140 will be described below.

FIG. 3 is a block diagram illustrating the functional configuration of the medium conveying section 140. As shown in FIG.
As shown in FIG. 3A, the control unit 141 of the medium transport unit 140 includes a RAM 1411 (storage unit), a register 1412, a control circuit 1413 (control unit, acquisition unit), an input/output I/F 1414, It includes a buffer 1415, a current controller 1416, and the like.

The RAM 1411 stores temporary setting values and the like. As the RAM 1411, high-speed reading and writing are possible, and an SRAM is used here, but a non-volatile memory such as an MRAM or FeRAM may be used. The RAM 1411 stores a speed table 1411a and an acceleration table 1411b (collectively motion speed information) as index values related to rotation speed. Writing to the velocity table 1411 a and the acceleration table 1411 b is performed from the external control unit 11 via the input/output I/F 1414 . The written speed table 1411a and acceleration table 1411b are referred to and read out by the control circuit 1413 when accelerating or decelerating the rotational speed of the stepping motor 143a.

A register 1412 stores a setting value related to conveying speed control. An acceleration/deceleration setting 1412 a is stored in the register 1412 and referred to by the control circuit 1413 . The write setting of the acceleration/deceleration setting 1412 a is performed by the control unit 11 via the input/output I/F 1414 . The contents of these acceleration/deceleration settings 1412a may be written and stored in the RAM 1411 together with the speed table 1411a and the acceleration table 1411b.

The control circuit 1413 controls the stepping motor 143a and the brushless motor 143b to operate at an appropriate speed (operating speed) by the drive signal output unit 142 based on the speed table 1411a, the acceleration table 1411b, and the acceleration/deceleration setting 1412a. Outputs drive control signals. The control circuit 1413 has a counting circuit 1413a (counter circuit), and outputs a driving control signal that switches each time a clock signal of a predetermined frequency is counted a specified number of times. In the above example, the brushless motor 143b switches the polarity (phase) three times more frequently than the stepping motor 143a. ratio) is synchronized with the drive control signal, and the remaining two times may be switched according to the detection state of the rotation of the rotor. The control circuit 1413 performs control operations here based on the control of the control unit 11 using a dedicated hardware circuit (such as an ASIC).

The input/output I/F 1414 switches the input signal from the outside of the control unit 141, here, the control unit 11, to the RAM 1411 and the register 1412 and outputs it, and also switches the setting data of the RAM 1411 and the register 1412 to output the input signal to the control unit 141. Output to the outside (control unit 11). Switching can be performed based on a control signal from the control unit 11 .

A buffer 1415 receives a trigger signal at the start of transportation to the control circuit 1413 and outputs it at an appropriate timing in synchronization with the clock signal. As a result, the timing for starting the transportation, the timing for starting the speed change, and the timing for ending the transportation can be aligned.

The current control section 1416 outputs the power supply voltage (power) supplied to the control section 141 . The output voltage is applied to the stator of the stepping motor 143a after being switched to have an appropriate polarity (and current flow path) based on the drive signal from the first signal output section 142a. Also, the polarity according to the switching by the second signal output unit 142b and the voltage according to the PWM control are applied to the stator of the brushless motor 143b. As a result, each stator generates a magnetic field according to the flowing current, and the rotor rotates according to the magnetic force acting between the magnetic field and the magnet (permanent magnet) of the rotor. A status signal is output from the control circuit 1413 to the current control unit 1416 to indicate whether it is acceleration or deceleration during acceleration or deceleration. If the stepping motor 143a and the brushless motor 143b can rotate in reverse, the status signal may include information indicating forward rotation or reverse rotation.

A clock signal CLK having a predetermined frequency and a reset signal RST are input to the control unit 141 .

The counting circuit 1413a of the control circuit 1413 has a counter 21, a logic circuit 22, and a flip-flop circuit 23 (FF), as shown in FIG. 3B.
The counter 21 counts the number of times the clock signal CLK is input, and outputs a predetermined signal to the logic circuit 22 when the counted number (count number) reaches the count setting value 211 . The value counted by the counter 21 is reset and initialized to "0" when the count number reaches the count setting value 211, and the count from "0" is counted as it is. Alternatively, the counter 21 holds the value of the remainder obtained by dividing the number of counts by the count set value 211, and at the timing when the value of the remainder returns to "0", each motor of the drive section 143 is sent to the predetermined drive signal output section 142. It can be configured to output a signal for rotating. Hereinafter, it will be described that "the value counted by the counter 21 becomes the count setting value 211" including the case of this configuration.

The logic circuit 22 inverts the logic each time a signal is input from the counter 21 to alternately switch between high level (H) and low level (L). The flip-flop circuit 23 is a D flip-flop here, holds the voltage level related to the output logic from the logic circuit 22 in synchronization with the CLK signal, and outputs the drive control signal of the voltage level to the drive signal output section 142. Output. Then, the drive signal output unit 142 operates the motor of the drive unit 143 every time the voltage level of the drive control signal changes, and switches the drive signal for synchronizing the rotation phase.

As the count setting value 211 of the counter 21, a value calculated based on the value read from the speed table 1411a of the RAM 1411 or the value read from the acceleration table 1411b is set and stored. That is, the reciprocal of the count set value 211 becomes a value (appropriate factor multiplication) corresponding to the rotation speed of each motor of the drive unit 143 .

When rotating the stepping motor 143a, the first signal output unit 142a changes the polarity of the magnetic field generated by the stator at predetermined intervals by a predetermined angle (movement amount of a predetermined unit amount), for example, by inverting it by 180 degrees. , rotates the rotor in angular steps according to the angle change. When rotating the brushless motor 143b, the second signal output unit 142b changes the magnetic field of each stator according to the rotational position of the rotor, and continuously applies force to the rotor in the rotational direction. to keep the rotor spinning.

Next, the conveying operation of the conveying medium in the image forming apparatus 1 of this embodiment will be described.
As described above, in the image forming apparatus 1, the conveying medium moves at a moving speed corresponding to the rotation speed of the stepping motor 143a and the brushless motor 143b (the number of CLK signal inputs counted during rotation of a predetermined angle (180 degrees)). is moved by At this time, the rotation speed of each motor of the drive unit 143 does not immediately transition between the initial speed (stopped state, etc.) and the target speed due to the magnitude of torque, etc., and the shift period (speed increase period and/or speed period of decline). Also, when the stepping motor 143a is overloaded and the rotational speed change is not normal, the driving force (voltage amplitude) of the brushless motor 143b is increased to assist the operation of the stepping motor 143a.

FIG. 4 is a diagram for explaining speed changes of each motor of the drive unit 143 in the image forming apparatus 1 of this embodiment.

As shown in FIG. 4(a), each motor of the driving unit 143 rotates at a constant speed at a predetermined speed during a period R3 before and after the speed is changed, during which the rotational speed increases (slows up) during a period R1. , R2, and periods R4 and R5 during which the rotational speed decreases (slowdown) are set. Of these, in periods R1 and R5, the rotational speed changes with a constant acceleration with respect to the time axis (elapsed time), and in periods R2 and R4, the acceleration at each connection with periods R1 and R5 is faster than that in period R3. The rotation speed changes with the change in acceleration so that the acceleration at the connection portion with is reduced. In this way, by preventing sudden speed changes (i.e., instantaneously large acceleration) before and after transitioning to/from a constant-speed conveying operation, the position of the roller, conveying belt, and conveying medium during the conveying operation can be improved. To suppress occurrence of unevenness in moving speed, especially excessive variation (overshoot and undershoot) of moving speed at the time of acceleration stop. Here, the rise from the stop state (beginning of the period R1) and the transition to the stop state (end of the period R5) were exemplified as not involving changes in acceleration, but these cases also involve changes in acceleration. A change in rotational speed may be defined. Also, the acceleration change period may be provided at the start and/or end of the change, not limited to the start and stop of the rotation operation, even when the operation state at a predetermined speed is changed to another speed.

As shown in FIG. 4B, the drive control signal output from the control circuit 1413 (flip-flop circuit 23) of the control section 141 is a rectangular wave pulse that reciprocates between the high level signal H and the low level signal L. is a binary signal of shape. For each half period of this pulse, that is, each time the signal rises or falls, the first signal output section 142a changes the magnetic field polarity of the stator of the stepping motor 143a to rotate the rotor by a unit angle (for example, 180 degrees each). . When the speed changes, the second signal output section 142b also changes the magnetic field phase of the stator of the brushless motor 143b while synchronizing the timing of the predetermined reference phase (reference duty ratio) with this drive control signal. At this time, the degree of support of the stepping motor 143a by the brushless motor 143b is changed by changing the magnetic field strength, that is, the amplitude of the voltage (the maximum value of the duty ratio) according to the count setting value, that is, the rotation speed.

Here, the specified count numbers T1 to T13 that become the count set value 211 counted by the counter 21 for each rotation of the rotor of the stepping motor 143a are determined, and the specified count numbers T1 to T6 in the period R1 are determined when the speed is It is determined to rise with uniform acceleration. Further, the specified count numbers T7 to T12 in the period R2 are determined so that the speed is increased while the acceleration is gradually decreased, and the specified count number T13 is asymptotically approached. Then, in the period R3, it is fixed at a constant prescribed count number T13.

As described above, the counting circuit 1413a may be provided with both a variable counting circuit in which the count setting for each half cycle of the drive control signal is determined and a fixed counting circuit maintained at a fixed number of times during the period R3. In this case, the variable counting circuit is used in periods R1, R2, R4, and R5, and the fixed counting circuit is used in period R3. Even with a fixed counting circuit, the count setting value 211 can be updated according to the fixed number of times that is maintained, and is determined based on the type of transport medium and the recording mode (image resolution, etc.) or reading mode. Just do it.

FIG. 5 is a chart showing examples of the velocity table 1411a and the acceleration table 1411b.
Among these, the speed table 1411a may be provided in a plurality of types. Also, here, the acceleration table 1411b holds only a single table.

In the speed table 1411a shown in FIG. 5A, next reference addresses and specified counts (arrangement of speed index values) are stored in association with addresses. The prescribed count number is determined so that the reciprocal value (i.e., speed) increases at a constant rate with respect to the time axis (count integrated value from the start of counting) (i.e., constant acceleration). . The next reference address indicates the address information of the specified count number to be read next to the specified count number related to the current reference address and determined as the count setting value 211 . When the rotational speed of the stepping motor 143a and the brushless motor 143b is increased from the stop state (period R1), the address indicated by the next reference address from the address "0" (that is, the order of increasing one by one from the address "0"). are sequentially read out and determined as the set count value 211, and the speed is sequentially changed according to the arrangement order of the specified count numbers. When the stepping motor 143a and the brushless motor 143b are reduced from the predetermined rotation speed (period R5), the next reference address is set to be the previous address, and the specified count number is set in the order of decreasing one by one from the maximum address. are read in order, and the speed is changed in sequence according to the arrangement order of the specified count numbers. That is, the speed table 1411a is used here during a period in which the acceleration is constant among the periods in which the rotation speed is changed.

A plurality of types of speed tables are defined (according to a plurality of set accelerations) such that the constant ratio, that is, acceleration differs from each other. As will be described later, when a corrected speed profile is set, it may be determined that a speed table with acceleration greater than the original speed table is read and used.

In the acceleration table 1411b shown in FIG. 5B, next reference address offsets and acceleration set values (array of acceleration index values) are stored in association with addresses. During the above-described periods R2 and R4 (at least one of a predetermined period from the start of the acceleration change period and the rotation speed change period and a predetermined period before the end), the acceleration set value specified for the initial speed is used to determine the next count setting value 211 . The acceleration set value can be a value that is determined according to the acceleration value, regardless of the count number. The next reference address offset value is a relative address within the acceleration table 1411b, but it may be an absolute address (physical address, here, from "256") (see FIG. 7B). The acceleration setting value stored here is an absolute value, and the control circuit 1413 performs the processing of decreasing and increasing the count setting value 211 when the speed increases and decreases.

FIG. 6 is a chart showing an example of the acceleration/deceleration setting 1412a set in the register 1412. As shown in FIG.
FIG. 6(a) shows the settings used when the speed of the stepping motor 143a and the brushless motor 143b is increased from the stopped state, and FIG. This setting is used when the speed is slowing down.

These speed-up settings and speed-down settings can be made to registers 1412 separately. These settings may be made by the control unit 11 when the type of recording medium (conveyance medium) for image formation and/or the recording mode (reading mode) are set, and may be written and set in the register 1412 .

As shown in FIG. 6A, the acceleration/deceleration setting 1412a is set to the effect that the acceleration/deceleration type is used for speed "increase" as a setting for speed increase (acceleration) (actually, It may be either of the two values previously determined in association with the speed increase/speed decrease. Also, for the setting at the time of speed increase, the timing (point of inflection) at which the speed setting with constant acceleration using the speed table 1411a (period R1) shifts to the speed setting (period R2) using the acceleration table 1411b is set. , the address indicating the acceleration value (inflection point reference) first used when transitioning to the speed setting using the acceleration table 1411b, and the speed to be finally reached by the speed setting using the acceleration table 1411b A target count value indicating (set count value for period R3; predetermined target speed) is stored.

The inflection point address is usually determined according to the target count value. By changing the speed based on the same acceleration change from the specified count number (initial value) of an arbitrary inflection point address, that is, the acceleration set value in the common range in the single acceleration table 1411b, A target count value corresponding to the curve point address can be asymptotically approached. Further, the initial acceleration, that is, the inflection point reference destination address (that is, the range used for calculating the rotation speed) is set for each of the plurality of speed tables corresponding to the plurality of accelerations (set acceleration). , the velocity can be varied based on the acceleration set values within the preferred range in the single acceleration table 1411b to asymptotically approach the target count value.

When the speed increases, first, the prescribed count numbers are read out in order from the address "0" of the speed table 1411a and set as the count set value. When the specified count number is counted corresponding to the address indicating the inflection point, the acceleration setting value of the address to which the inflection point is referred is referred to, and the acceleration setting value is used to decrease the current count setting value. Calculation is performed to calculate and set a new count setting value. After this count set value is counted, the next acceleration set value is referred to and the count set value is updated sequentially. Then, when this count set value becomes equal to or less than the target count value (when the target speed is reached), the target count value is set to the count set value and accelerated (the period during which the speed is changed, here the acceleration is period to change) ends.

On the other hand, as shown in FIG. 6B, the acceleration/deceleration setting 1412a is set to indicate that the acceleration/deceleration type is used for "decreasing" the speed as the setting for speed decrease. Also, the settings when the speed decreases include the initial speed setting, the initial acceleration address in the acceleration table 1411b, the speed setting with a gradually decreasing acceleration (<0) using the acceleration table 1411b (period R4), and the speed setting with constant acceleration. An address indicating the timing (point of inflection) to shift to (period R5) and an address indicating the speed value (referred to point of inflection) initially used when shifting to speed setting using the speed table 1411a are stored. ing. Note that the initial acceleration address may be fixed (for example, "280"). In this case, there is no need to store this value (address) in register 1412 . Also, the initial speed is determined in pairs with the address of the inflection point reference according to the speed in the period R3, and is used to select this setting and store it in the acceleration/deceleration setting 1412a of the register 1412. be.

When the speed decreases, the acceleration setting value of the initial acceleration address is referred to from the acceleration table 1411b, and the next count setting value 211 is calculated and set based on the acceleration setting value and the current speed (count setting value). When the count setting value 211 is counted by the counting circuit 1413a, the address for obtaining the acceleration setting value is decremented one by one according to the next reference address offset value, and the count setting value 211 is sequentially calculated until the address reaches the inflection point. is calculated and set. When the count set value 211 based on the acceleration set value corresponding to the address of the inflection point is counted, the prescribed count number referred to at the inflection point is acquired from the speed table 1411a and used as the count set value 211 as it is. Further, when the count setting value 211 is counted, the reference address of the speed table 1411a is decremented by one. After the predetermined count number "13332" of the address "0" is counted and the drive control signal is output, the stepping motor 143a is stopped and the operation control is finished.

That is, in the image forming apparatus 1 of the present embodiment, when the rotational speed of the stepping motor 143a is accelerated or decelerated, that is, when the rotational speed is changed, the rotational speed is increased at a constant acceleration according to the arrangement of the prescribed count numbers in the speed table 1411a. The drive signal output by the first signal output unit 142a by combining the determined period and the period determined by calculating the rotation speed while changing the acceleration based on the arrangement of the acceleration set values in the acceleration table 1411b, that is, the stepping motor The polarity (direction of current) of the voltage applied to the stator of 143a is controlled.
In addition, the calculated rotation speed (count setting value) exceeds the target speed (target count value). ), the final rotation speed is set to the target speed, and the control operation related to the speed change is terminated.
Also, the same (common) speed table 1411a and acceleration table 1411b are used when the speed increases and when the speed decreases, and the order of reading the array data (specified count number and acceleration set value) in each table is reversed. be.

The image forming apparatus 1 does not determine the next reference address by comparing the inflection point address of the acceleration/deceleration setting 1412a of the register 1412 with the actual reference address, but sets the next reference address itself based on the acceleration/deceleration setting 1412a. can be changed by

FIG. 7 is a chart showing an example of rewriting the velocity table 1411a and the acceleration table 1411b.

As shown in FIG. 7(a), in the speed table 1411a used when the speed increases, the address "262" of the acceleration table 1411b can be directly specified as the next reference address after the address "4". Further, as shown in FIG. 7B, in the acceleration table 1411b used when the speed decreases, the address "4" of the speed table 1411a can be directly specified as the reference address next to the address "262". . By designating the next reference address in this way, it is possible to slightly reduce the load of the determination processing involved in acquiring and calculating the count set value during the acceleration/deceleration operation.

In these cases, the control circuit 1413 can separately store and hold the changed original address information in the RAM 1411 so that it can be initialized after the end of the acceleration/deceleration operation. Alternatively, the initialization operation may be performed by the control unit 11 overwriting the original data of the storage unit 113 in the RAM 1411 or the like. Also, the rewriting operation of the next reference address may be directly performed by the control unit 11 when writing the setting to the register 1412 and the RAM 1411, or may be performed by the control circuit 1413 based on the acceleration/deceleration setting 1412a of the register 1412.

The acceleration/deceleration operation of the normal conveying speed is performed as described above. However, due to various factors such as an abnormality in the conveying medium, for example improper placement or setting mismatch, the speed change may temporarily not be properly controlled.

FIG. 8 is a diagram illustrating an abnormality in speed change.
As shown in FIG. 8A, while the rotational speed of the stepping motor 143a is increasing (during acceleration), the speed is not properly changed as described above, and the load La of the stepping motor 143a abnormally increases. Sometimes. At this time, the load Lb of the brushless motor 143b also increases at the same time. When the load detector 144 detects such a load abnormality (fluctuation) in the middle of the speed change and outputs the detection result to the control circuit 1413 (timing P11), the detection result is displayed as shown in FIG. The acquired control circuit 1413 of the control unit 141 suspends (interrupts, decreases the absolute value of acceleration) the speed increase (interval R1S). In addition, the control circuit 1413 of the control unit 141 temporarily increases (increases) the torque (driving force) of the brushless motor 143b, that is, increases the amplitude of the voltage phase change, thereby operating the stepping motor 143a. Assist. The load La of the stepping motor 143a is reduced in accordance with this assist operation. When the load abnormality (increase) is eliminated (timing P12), the control circuit 1413 cancels (finishes) the temporary suspension of the speed increase (speed change), and restarts the increase of the rotational speed of the stepping motor 143a. . Abnormalities in the load are detected based on a comparison between an assumed load amount calculated in advance based on the type of medium to be conveyed and the conveying speed, etc., and a reference value, or simply on the basis of the amount of deviation from the average value of the load detected most recently. can be discriminated.

The control unit 141 temporarily increases the rate of increase in speed after the restart of the speed increase, that is, the absolute value of the acceleration, so as to compensate for the delay in the speed increase caused by the stoppage of the acceleration of the stepping motor 143a ( raised) can be set (interval R12). When the rotation speed (assumed value) that was originally determined before the load abnormality was detected (before the detection result indicating the load fluctuation was obtained) and the actual rotation speed became equal (timing P13), the control unit 141 controlled the stepping motor The speed increase of 143a (temporary increase in the absolute value of acceleration) is restored as originally planned (temporary increase is terminated), and the torque of brushless motor 143b is restored (increase in driving force is terminated). ). Here, before the assumed value reaches the target speed (target count value) (within the period during which the operation speed was originally scheduled to be changed), the amount of increase in acceleration is set so that the actual rotation speed becomes equal to the assumed value. However, if the acceleration becomes too large, it is not necessary to completely recover the delay in speed increase. That is, the speed increase may end after the timing at which the speed increase should normally end. In this case, the inflection point may also be changed to a higher acceleration address.

When the control circuit 1413 changes the operating speed as described above due to acquisition of the detection result indicating the load fluctuation, the control circuit 1413 selects at least one of the speed table 1411a and the acceleration table 1411b according to the planned speed change ( operating speed information) as necessary.

FIG. 9 is a flow chart showing the control procedure of the acceleration/deceleration control process executed by the image forming apparatus 1 of this embodiment.
This acceleration/deceleration control process, which is the rotational motion control method of the embodiment of the present invention, is a start instruction to the control circuit 1413 via the input/output I/F 1414 under the control of the control unit 11. It is started by inputting a command (including start) or a command to slow down (including stop operation).

When the acceleration/deceleration control process is started, the control circuit 1413 acquires the acceleration/deceleration setting 1412a set in the register 1412 by the control unit 11 (step S101). At this time, the control circuit 1413 sets the next reference address (next reference address offset) of the speed table 1411a and the acceleration table 1411b based on the acceleration/deceleration setting 1412a according to the configuration of the drive signal output section 142 and necessity. The control circuit 1413 determines whether or not the acceleration/deceleration type of the setting content is the speed increase setting (step S102). If it is determined that the speed is set to increase ("YES" in step S102), the control circuit 1413 refers to the speed table 1411a and initializes the prescribed count number ("13332") corresponding to the address "0". It is obtained as a value and set as the count set value 211 (set value) of the counter circuit 1413a (step S103). Also, the duty ratio may be determined according to this set value.

The control circuit 1413 causes the counter 21 to start counting (step S104). When the control circuit 1413 has a fixed counting circuit and a variable counting circuit as described above, switching is performed so that the drive control signal is output from the variable counting circuit.

The control circuit 1413 compares the input load detection signal with a predetermined reference range to determine whether there is an abnormality in the load (step S105). If it is determined that there is an abnormality in the load ("YES" in step S105), the processing of the control circuit 1413 proceeds to step S106 to perform abnormality handling control processing. When the abnormality handling control process ends in step S106, the process of the control circuit 1413 proceeds to step S107. If it is determined that there is no load abnormality ("NO" in step S105), the processing of the control circuit 1413 proceeds to step S107.

After shifting to the process of step S107, the counter 21 determines whether or not the counted value (count value) is equal to or greater than the value (set value) set in the count set value 211 (step S107). If it is not equal to or greater than the set value ("NO" in step S107), the process returns to step S105 for each count operation.

When it is determined that the count value is equal to or greater than the set value of the count set value 211 (“YES” in step S107), the control signal is output from the counter 21 to the logic circuit 22 and output from the control circuit 1413. The drive control signal is switched. Also, the count value is reset and returns to "0".

At this time, the control circuit 1413 determines whether the reference operation of the velocity table 1411a or the acceleration table 1411b has already passed the inflection point, that is, whether the next reference address is the address of the acceleration table 1411b (step S108). If it is determined that it is not after the inflection point ("NO" in step S108), the control circuit 1413 refers to the data of the next reference address in the speed table 1411a and acquires a new prescribed count number. Then, the obtained value is set as the count setting value 211, and the duty ratio is set (step S109). The processing of the control circuit 1413 then returns to step S105.

If it is determined in the determination process of step S108 that the current state is after the inflection point ("YES" in step S108), the control circuit 1413 refers to the acceleration table 1411b to acquire the acceleration set value. The control circuit 1413 calculates a new set value (speed) from the current count set value 211 and the acquired acceleration set value, sets it in the counter 21, and sets the corresponding duty ratio (step S110). ). Here, only a new setting value is calculated, and the setting to the count setting value 211 may be performed according to the determination result of step S111, which will be described later.

The control circuit 1413 determines whether the set value set in the count set value 211 according to the calculated speed is equal to or less than the count value (target value) according to the speed after change by the acceleration/deceleration control process, that is, the speed It is determined whether or not the target speed for ascent has been reached (step S111). If it is determined that it is not equal to or less than the target value ("NO" in step S111), the processing of control circuit 1413 returns to step S105.

When it is determined that the set value is equal to or less than the target value ("YES" in step S111), the control circuit 1413 sets the target value in the counter 21 as the count set value 211 (step S112). As described above, when the fixed counting circuit is provided separately from the variable counting circuit, the target value may be set to the count setting value of the fixed counting circuit at this timing, or may be set in advance in step S101 or the like. It may be Then, in the process of step S112, the drive control signal is switched to be output from the fixed counting circuit. Then, the control circuit 1413 terminates the acceleration/deceleration control process. Thereafter, the drive control signal is output from the control circuit 1413 at fixed intervals each time the target value is counted.

On the other hand, if it is determined in the determination processing in step S102 that the speed increase setting is not set, that is, if the acceleration/deceleration type is determined to be the speed decrease setting (“NO” in step S102), the control circuit 1413 updates the speed table 1411a. The acceleration table 1411b is referenced to obtain the prescribed count number of the initial velocity address, and the acceleration setting value of the initial acceleration address is obtained by referring to the acceleration table 1411b. The control circuit 1413 applies the acceleration set value to the obtained prescribed count number to calculate the next set value, sets it as the count set value 211, and sets the corresponding duty ratio (step S123). . At the start of speed reduction, the count set value 211 has already been set, and the stepping motor 143a is rotating at a constant speed or accelerating, so the specified count number of the initial speed address is not acquired and the currently set value is set. Alternatively, the next set value may be calculated by applying the acceleration set value directly to the set value for the count set value 211 , and set as the count set value 211 .

The control circuit 1413 compares the input load detection signal with a predetermined reference range to determine whether there is an abnormality in the load (step S124). If it is determined that there is an abnormality in the load ("YES" in step S124), the processing of the control circuit 1413 proceeds to step S125 to perform abnormality handling control processing. When the abnormality handling control process ends in step S125, the process of the control circuit 1413 proceeds to step S126. If it is determined that there is no load abnormality ("NO" in step S124), the processing of the control circuit 1413 proceeds to step S126.

After shifting to the process of step S126, the control circuit 1413 determines whether or not the count value is equal to or greater than the set value (step S126). If it is determined that the count value is not equal to or greater than the set value ("NO" in step S126), the processing of control circuit 1413 returns to step S124.

When it is determined that the count value is equal to or greater than the set value ("YES" in step S126), the control signal is output from the counter 21 to the logic circuit 22, and the drive control signal output from the control circuit 1413 is switched. . Also, the count value is reset. The control circuit 1413 determines whether the reference operation of the speed table 1411a or the acceleration table 1411b is an inflection point address, that is, whether the next reference address is before the address of the acceleration table 1411b (step S127). If it is determined to be before the inflection point ("YES" in step S127), the control circuit 1413 refers to the value of the next reference address offset in the acceleration table 1411b to acquire the acceleration set value, Using the acceleration set value and the count set value 211, the next set value is calculated. The control circuit 1413 sets the calculated set value to the counter 21 as the count set value 211, and also sets the corresponding duty ratio (step S128). Then, the processing of control circuit 1413 returns to step S124.

If it is determined in the determination process of step S127 that the time is not before the inflection point (it is after the inflection point) ("NO" in step S127), the control circuit 1413 refers to the speed table 1411a, and the following , and sets the count setting value 211 as the next setting value, and also sets the corresponding duty ratio (step S129). The control circuit 1413 determines whether or not the set value is equal to or greater than the target value corresponding to the target speed after speed reduction (step S130). If it is determined that it is not equal to or greater than the target value ("NO" in step S130), the processing of control circuit 1413 returns to step S124.

If it is determined that the set value is equal to or greater than the target value ("YES" in step S130), the control circuit 1413 sets the target value to the upper limit value related to the operation of the stepping motor 143a, for example, "7659" in this case. That is, it is determined whether or not it is larger than the second largest (slowest operation) value in the speed table 1411a (step S131). If it is determined that the target value is not greater than the upper limit value (below the upper limit value) ("NO" in step S131), the processing of the control circuit 1413 proceeds to step S112.

If it is determined that the target value is greater than the upper limit value ("YES" in step S131), the control circuit 1413 sets "0" as the count setting value 211 and stops the counting operation by the counter 21 (step S131). S132). Then, the control circuit 1413 terminates the acceleration/deceleration control process while stopping the rotation of the stepping motor 143a.
Among the above processes, steps S105 and S124 correspond to the acquisition step of the drive control process of this embodiment. Other processing indicates specific contents of the control step.

FIG. 10 is a flow chart showing the control procedure of the abnormality handling control process called in steps S106 and S125 of the acceleration/deceleration control process. This abnormality response control process indicates the content of the speed change according to the abnormal load in the control step of the drive control method of this embodiment.

When the abnormality handling control process is called, the control circuit 1413 suspends the speed change (step S201). The control circuit 1413 continues the rotation operation at a fixed speed (constant speed) according to the current set value. When a fixed counting circuit and a variable counting circuit are provided, the control circuit 1413 sets the count set value 211 of the fixed counting circuit to the same value as the current count set value 211 of the variable counting circuit, and outputs the drive control signal. output to a fixed counting circuit. Also, the torque (such as the duty ratio in each phase) of the brushless motor 143b driven by the second signal output section 142b is increased by a predetermined amount.

Based on the input load detection signal, the control circuit 1413 determines whether or not the load increase (increase) has converged (whether or not the increase exceeding the reference value has been eliminated) (step S202). If it is determined that the convergence has not occurred ("NO" in step S202), the control circuit 1413 repeats the process of step S202. If it is determined that convergence has occurred ("YES" in step S202), the control circuit 1413 calculates a correction speed profile for catching up with the original speed based on the elapsed time from the interruption of the speed change until detection of convergence. (step S203). For example, the control circuit 1413 refers to the speed table 1411a with acceleration greater than the acceleration of the speed table 1411a set for use within a predetermined difference range, and changes the current speed (set value) to the original speed ( It may be set so that each prescribed count number until it catches up with (becomes equal to) the set value) is used in order. The setting in this case may be made by overwriting and correcting the next reference address in the velocity table 1411a and the acceleration table 1411b. For this overwrite correction, first, the current speed is set as the initial speed, the calculated acceleration is set as the initial acceleration, and the transfer point address of the timing of transition between the speed tables 1411a of different accelerations, etc. If set, the acceleration/deceleration setting 1412a may be overwritten and additionally modified. Alternatively, the control circuit 1413 calculates and specifies an appropriate acceleration for catching up with the original speed, calculates all the speeds (prescribed counts) of each step until the actual speed is caught up with the original speed, and calculates the current speed. You may overwrite the specified count number of the set speed table 1411a.

The control circuit 1413 specifies the address of the set value at the start of correction and the address of the set value at the end of correction (step S204), and when the current count value reaches the set value, the drive control signal (reference phase The count set value 211 is updated to the first set value at the timing when the duty ratio) is switched (step S205). Further, it may be output to the second signal output section 142b as a drive control signal indicating the setting of the voltage amplitude (duty ratio) according to the set value. When the output of the drive control signal is switched to the fixed counting circuit, it is switched to the output of the drive control signal from the variable counting circuit at an appropriate timing (timing when the count value reaches the set value).

The control circuit 1413 determines whether or not the count value is greater than or equal to the set value (step S206). If it is determined that the count value is less than the set value ("NO" in step S206), the control circuit 1413 repeats the process of step S206. If it is determined that the count value is equal to or greater than the set value ("YES" in step S206), all of the correction set values defined in the correction speed profile have been set, and the original operation speed has been restored (catch up). (step S207). That is, the timing determined here is the timing of switching from the speed table 1411a set for correction to the originally set speed table 1411a.

If it is determined that there are still correction set values that have not been set ("NO" in step S207), the control circuit 1413 sets the next correction set value and the corresponding duty ratio (temporary ) is set (step S208). Also, the count value is reset. Then, the processing of control circuit 1413 returns to step S206.

When it is determined that all the correction set values have been set and the original operating speed has been restored ("YES" in step S207), the control circuit 1413 corresponds the specified count value that is the restored original set value. It is read from the address, acquired, and set as the count setting value 211 (step S209). Then, the interrupted speed change is resumed from the set value of the return position. Also, the temporary increase in torque of the brushless motor 143b is restored. If the operating speed catches up with the target value at the timing after the original speed change is completed according to the correction speed profile, the target value is set as the count setting value 211 as it is, and the constant speed operation (by the fixed counting circuit) is performed. counting). Then, the abnormality handling control process by the control circuit 1413 ends, and the process proceeds to step S107 or step S126.

[Modification]
FIG. 11 is a schematic diagram illustrating a modification of power transmission from the drive unit 143 to the conveying medium.
In Modified Example 1 shown in FIG. 11(a), two stepping motors 143a and 143c have rotating shafts 143a1 and 143c1, respectively. The rotating motion of the rotating shaft 143a1 is transmitted to the roller 201a, and the rotating motion of the rotating shaft 143b1 is transmitted to the roller 202a. That is, in this case, driving force is not transmitted to the same transmission shaft for each driving portion 143 . In the image forming apparatus 1a (see FIG. 12) having these stepping motors 143a and 143c, a driving force is individually applied to the medium M, which is the same object to be operated, through the rollers 201a and 202a. The medium M is moved at a moving speed corresponding to . Here, the rollers 201a and 202a (positions where the stepping motors 143a and 143c respectively apply the driving force to the medium M) are arranged in the width direction perpendicular to the movement direction (conveyance direction) of the medium M. Then, the rollers 201a and 202a do not need to have this positional relationship. The rollers 201a and 202a may be positioned at different positions in the transport direction.

FIG. 12 is a block diagram showing the functional configuration of an image forming apparatus 1a according to Modification 1. As shown in FIG.
The medium conveying unit 140 has an operation detection unit 146 (movement amount detection unit) in addition to the stepping motor 143c described above. As the motion detection unit 146, a motion detection unit 1461 that detects the amount of rotation of the rotation shaft 143a1 (predetermined position) (amount of motion; the amount of motion per unit time is the motion speed), and a motion detection unit 1461 that detects the amount of rotation of the rotation shaft 143c1. A detector 1462 is provided. The motion detection units 1461 and 1462 are, for example, rotary encoders. The count set value 211 is determined identically by the speed table 1411a and the acceleration table 1411b (same operation speed information), and a common drive control signal is output to the first signal output section 142a and the second signal output section 142b to perform the operation. control may be made. If one of the stepper motors 143a, 143c is overloaded and the speed changes (decreases), the speeds of the stepper motors 143a, 143c are kept synchronized and matched by updating the common setting. you can Further, when one of the stepping motors 143a and 143c is overloaded, control may be performed to increase the torque of the other. That is, the stepping motors 143a and 143c do not need to have a master-slave relationship. Note that the rotary encoder may also be used as a load detector.

Other configurations are the same in the image forming apparatuses 1 and 1a, and the same configurations are denoted by the same reference numerals, and descriptions thereof are omitted.

FIG. 13(a) is a flow chart of speed adjustment processing in the image forming apparatus 1a of the first modification. This process is activated when one of the motion detection units 1461 and 1462 detects a speed change. The control circuit 1413 changes (corrects) and updates the current operating speed setting by the magnitude of the change according to the magnitude of the detected change (step S251). As a result, the rotational speeds of the stepping motors 143a and 143c are rapidly synchronized. It should be noted that the speed change referred to here is not limited to that caused by an abnormality that poses a problem in operation as described above, but here, the entire deviation of the speed from the assumed value will be described as the speed abnormality.

In Modification 2 shown in FIG. 11B, in addition to Modification 1, the image forming apparatus 1b (see FIG. 14) further includes a medium detection unit 147 (object detection unit) for measuring the position of the medium M to be moved. Two (plural) are provided. The medium detection unit 147 is, for example, an optical sensor capable of detecting the presence or absence of the medium M by capturing an image of the transport surface of the medium M, and particularly capable of specifying the leading edge position of the medium M.

FIG. 14 is a block diagram showing the functional configuration of an image forming apparatus 1b of Modification 2. As shown in FIG.
A medium detection unit 147 is added to each component of the image forming apparatus 1a. Other configurations are the same between the image forming apparatuses 1a and 1b, and the same configurations are denoted by the same reference numerals, and descriptions thereof are omitted.

As shown in FIG. 11B, the two medium detection units 147 are arranged in parallel at the same position in the transport direction indicated by the arrows and at different positions in the width direction perpendicular to the transport direction. They are located near both ends so as to detect the presence or absence of the medium M (that is, to detect the state of movement of the medium M in the transport direction). A detection signal of the medium M is input to the control circuit 1413, and the inclination of the medium M with respect to the transport direction is specified according to the difference in detection timing.

In the case of Modified Example 2, in addition to the above-described control when the speed changes, the rotation speed of each motor of the driving section 143 is controlled according to the inclination of the medium M. Here, the delay is recovered and the tilt is eliminated by correcting the rotation speed of the stepping motor on the side where the medium M is detected with delay so as to be temporarily higher than the rotation speed of the other stepping motor.

FIG. 13B is a flow chart showing a control procedure by the control circuit 1413 of the medium orientation adjustment process. This medium orientation adjustment process is started when a new medium M is conveyed and detected by the two medium detectors 147 .

The control circuit 1413 determines whether or not the detection timing difference between the two medium detection units 147, that is, the inclination of the medium M is detected (step S301). If it is determined that no deviation has been detected ("NO" in step S301), the control circuit 1413 terminates the medium orientation adjustment process.

If it is determined that a deviation has been detected ("YES" in step S301), the control circuit 1413 sets the operating speed of one of the stepping motors detected later (step S302). In addition, if only one stepping motor is insufficient, setting may be made to lower the operating speed of the other stepping motor. In this case, since the drive control signal is different between the output to the first signal output section 142a and the output to the second signal output section 142b, the control circuit 1413 has a plurality of counting circuits 1413a which operate separately. good. Also, since the amount of increase (the amount of decrease) in the operating speed may be constant, there is no need to correct the entire speed table 1411a, and fixed count set values 211 may be determined for each.

The control circuit 1413 determines whether or not the tilt of the medium M has been eliminated (step S303). The control circuit 1413 does not need to directly detect the inclination of the medium M again. It may be determined by counting the elapsed time. If it is determined that the tilt has not been resolved ("NO" in step S303), the control circuit 1413 repeats the process of step S303. If it is determined that the tilt has been eliminated (“YES” in step S303), the control circuit 1413 returns the operating speed of the motor, which had been increased (and/or decreased), to the original speed to make it constant. (Step S304). Then, the control circuit 1413 ends the medium orientation adjustment process.

As described above, the control unit 141 as the drive control device of the present embodiment stores the speed table 1411a and the acceleration table 1411b, which are operation speed information of the drive unit 143 that generates the driving force applied to the transport medium (medium M). It has a RAM 1411 and a control circuit 1413 that controls the operating speed of the drive unit 143 based on the operating speed information. The control circuit 1413 , as an acquisition unit, acquires the detection result of the load detection unit 144 that detects the load of the driving unit 143 . The control circuit 1413 performs control to change the operating speed by changing the operating speed information when the detection result indicating the abnormality of the load is acquired.
In other words, when an abnormality in the load is detected, the control unit 141 changes the setting of the operation speed during that period to suppress the continuation and expansion of the influence of the abnormality, and facilitate the return to the proper operation speed. In particular, in the drive unit 143, the speed setting is performed using the speed table 1411a and the acceleration table 1411b, so by changing these, it is possible to easily change and correct the speed profile to an appropriate one. Therefore, the control unit 141 can control the operating speed of the drive unit 143 more flexibly and reliably.

In addition, the operating speed information (speed table 1411a) includes an array of prescribed count values related to the speed (rotational speed) of the drive unit 143, and when the control circuit 1413 changes the rotation speed of the drive unit 143, The rotation speed is sequentially changed according to the arrangement order of the specified count values, and when the detection result indicating the load abnormality is obtained during the change of the rotation speed, the absolute value of the acceleration related to the change of the rotation speed is decreased.
In this way, when an abnormality in the load that causes a problem in following the speed change is detected during the speed change, the speed change is slowed down (it may be a small acceleration value in the direction opposite to the initial speed change direction). ), it is possible to suppress the expansion of the influence of the abnormality and make it easier to return to the proper rotation speed.

Further, the control circuit 1413 suspends the change of the rotation speed when the detection result indicating the abnormality of the load is acquired during the change of the rotation speed. In other words, not only slowing the speed change, but also completely stopping it, it is possible to suppress the expansion of the deviation of the rotational speed due to the influence of the load, and facilitate the return to the proper rotational speed.

Further, the control circuit 1413 ends the reduction of the absolute value of the acceleration when the detection result indicating that the load abnormality has been resolved is obtained. That is, when the load abnormality is resolved, the speed change can be quickly resumed to shift to the target speed, thereby preventing unnecessary extension of the required time.

Further, the control circuit 1413 temporarily increases the absolute value of the acceleration when the detection result indicating that the load abnormality has been resolved is obtained. In other words, the time required to shift to the target speed is longer than originally planned by the amount of speed change temporarily suppressed due to an abnormal load. You can let As a result, extension of the required time can be suppressed.

In addition, the control circuit 1413 controls the rotational speed of the drive unit 143, which changes sequentially due to a temporary increase in the absolute value of the acceleration, and the change determined by the operation speed information before obtaining the detection result indicating the abnormality of the load. The temporary increase is terminated when the rotation speed is equal to the assumed value. When the acceleration temporarily increases to catch up with the initial scheduled speed in the middle of transition to the target speed, the acceleration may be returned to the scheduled value at that timing. If the vehicle reaches the target speed with a large absolute value of acceleration, overshoots or undershoots are likely to occur when reaching the target speed. It is possible to quickly start a desired operation (such as an image forming operation) after reaching the target speed.

In addition, the control circuit 1413 controls the rotation speed of the drive unit 143 to become equal to the assumed value within a period in which the rotation speed is scheduled to be changed according to the operating speed information before obtaining the detection result indicating the abnormality of the load. Determines the amount of temporary increase in the absolute value of acceleration.
By changing the acceleration setting in this way, even if an abnormality occurs in the load, it is possible to quickly suppress the abnormality and shift to the target speed without extending the required time. The operation of the drive unit 143 can be controlled.

The control circuit 1413 also includes a stepping motor 143a and a brushless motor 143b (or a stepping motor 143c) that generate a driving force applied to the same conveying medium. Even in the drive unit 143 that drives using a plurality of motors in this way, by changing the acceleration setting according to the load abnormality, it is possible to easily and quickly change the operation of the motor different from the motor that caused the load abnormality. It is possible to restore the normal rotation speed without increasing the abnormality.

Also, the brushless motor 143b gives torque to the same transmission shaft 201 as the stepping motor 143a. In this way, by applying a common torque to the transmission shaft 201 from a plurality of motors, even if an abnormality occurs in the load of the stepping motor 143a, the torque of the other brushless motor 143b is maintained while the abnormality of the stepping motor 143a is resolved. Therefore, it is possible to suppress the influence of the abnormality and maintain the driving force flexibly and more reliably.

Further, the control circuit 1413 can adjust the magnitude of the torque transmitted to the transmission shaft 201 by the brushless motor 143b, and increases the torque of the brushless motor 143b when a detection result indicating a load abnormality is acquired. In this way, by increasing the torque of the motor (brushless motor 143b) that is different from the motor (stepping motor 143a) in which the abnormality has occurred to support the operation of the stepping motor 143a, the load of the stepping motor 143a is corrected. can be quickly resolved and returned to a normal state.

In addition, the control circuit 1413 detects when the rotation speed of the stepping motor 143a and the estimated rotation speed corresponding to the change determined by the operation speed information before obtaining the detection result indicating the abnormality of the load are equal to each other. , terminate the increase in the torque of the brushless motor 143b. That is, while the stepping motor 143a is performing a load abnormality and recovery operation from the abnormality, the support operation of the brushless motor 143b is increased, and when the operation of the stepping motor 143a returns to normal, the brushless motor 143b The increase can be eliminated by eliminating the need for assisting operations. As a result, it is possible to quickly and reliably recover from the load abnormality, while suppressing an unnecessary increase in power consumption when the normal state is recovered. Thereby, the control unit 141 can flexibly and efficiently operate the driving unit 143 at an appropriate speed.

In addition, in the control circuit 1413 of Modification 1, the stepping motors 143a and 143c individually apply driving force to the conveying medium. In this way, each driving force may be applied to a common object without passing through the common transmission shaft 201 or the like. In this case, since an abnormality in the load of one stepping motor does not directly affect the operation of the other stepping motor, it is possible to eliminate the abnormality in the load while maintaining the driving state by the operation of the other stepping motor.

Also, the control circuit 1413 controls the rotational speed of the stepping motor 143a and the rotational speed of the stepping motor 143c based on the same operating speed information. When driving force is applied to the same object from a plurality of stepping motors 143a and 143c, the operations of the plurality of stepping motors 143a and 143c are interlocked, so that speed interlocking control can be easily achieved using the same information. .

In addition, the control circuit 1413 (acquisition unit) acquires the detection results of the operation detection units 1461 and 1462 that detect the rotation amounts of the rotation shafts 143a1 and 143c1 of the operation of the stepping motor 143a and the stepping motor 143c, respectively, and detects the operation. When the units 1461 and 1462 detect a change in the operating speed of one of the stepping motors 143a and 143c, the operating speed information is corrected in magnitude according to this change, and the rotation speed of the stepping motor 143a and the rotation of the stepping motor 143c are corrected. Match speed.
That is, when the two stepping motors 143a and 143c individually apply driving force to the same medium to be conveyed, the conveying speed must be synchronized. In this case, when one speed changes, the other speed can easily follow. It is possible to suppress the spread of influence.

Also, the motion detection unit 146 has an encoder. That is, since the motion detection unit 146 can accurately detect the amount of direct motion in real time, the control circuit 1413 can promptly detect an abnormality in the load and respond quickly and flexibly.

Also, the control circuit 1413 (acquisition unit) acquires the detection result of the medium detection unit 147 that detects the movement state of the medium to be conveyed in the predetermined conveyance direction. The stepping motors 143a and 143c are positioned side by side in the width direction perpendicular to the transport direction and apply a driving force to the transport medium to move the transport medium in the transport direction at a moving speed corresponding to the rotation speed. The control circuit 1413 identifies the inclination of the conveying medium with respect to the conveying direction based on the detection result of the medium detection unit 147, and corrects the rotation speed of at least one of the stepping motors 143a and 143c so as to remove the identified inclination. do.
In this manner, depending on the positional relationship of the stepping motors 143a and 143c, that is, how the driving force is transmitted from the stepping motors 143a and 143c to the conveying medium, it may be possible to operate them at different speeds. With such a configuration, it is also possible to adjust the speed so as to correct the inclination of the transported medium based on the detection result of the medium detection unit 147 . In this way, the conveying speed can be easily adjusted to an appropriate speed in various processes more flexibly.

In addition, the medium detection unit 147 has a plurality of sensors capable of detecting the presence or absence of the transported medium, and the sensors are arranged in parallel in the width direction perpendicular to the transport direction. The control circuit 1413 identifies the inclination of the conveyed medium according to the difference in detection timing of the conveyed medium by the plurality of sensors.
In this way, the sensors of the medium detection unit 147 are positioned at different positions in the width direction, particularly at both ends of the medium to be conveyed, so that the inclination of the medium can be easily detected. , it is possible to easily move the conveying medium in the correct direction. In addition, the same adjustment can be made even when the medium to be conveyed is tilted due to an abnormality in the operation of the stepping motors 143a and 143c.

Also, the plurality of sensors are optical sensors. By using a common optical sensor, it is possible to easily correct the orientation of the conveyed medium while avoiding an increase in cost and size.

Also, the load detection unit 144 measures the current supplied to the brushless motor 143b. This makes it possible to detect the load in real time easily and at low cost. Further, when detecting on the side of the second motor, it becomes easy to adjust the driving force of the second motor.

In addition, the driving section 143 has two rotary motors. By applying the above processing to drive control of rotary motors that tend to operate continuously, these rotary motors can be operated continuously, flexibly, and appropriately.

Further, the drive unit 143 has a brushless motor 143b as a support motor. By having a device that is capable of relatively strong and continuous rotation control even when the load is abnormal, more stable, flexible, and reliable speed control can be performed.

Further, the driving section 143 has two stepping motors 143a and 143c. In this way, by using the same motors side by side, it is possible to easily and accurately perform rotation control with similar characteristics. Also, even if any motor has an abnormality in load or a change in speed, the operation of the other motor assists the operation of the other motor, thereby facilitating recovery from the abnormality and adjustment.

Further, the image forming apparatus 1 of the present embodiment includes a drive unit 143 that generates force to be transmitted to a predetermined conveying medium, a load detection unit 144 that detects the load of the drive unit 143, and the control circuit 1413 as a drive control device. and a forming operation unit 13 that forms an image on the medium conveyed by the conveying unit 14 . In this image forming apparatus 1, it is possible to quickly suppress transport abnormalities, prevent troubles from spreading, and form images efficiently and accurately.

Further, the drive control method of the present embodiment includes a control step of controlling the rotation speed of the drive unit 143 based on the operating speed information, an acquisition step of acquiring the detection result of the load detection unit 144 that detects the load of the drive unit 143, In the control step, when a detection result indicating a load abnormality is obtained, control is performed to change the operating speed information to change the rotational speed. As described above, this drive control method makes it possible to control the operating speed of the drive unit 143 more flexibly and reliably.

It should be noted that the present invention is not limited to the above embodiments, and various modifications are possible.
For example, in the above embodiment, when an abnormality (fluctuation) in the load is detected, the speed change is interrupted, that is, the acceleration is controlled to be zero, but it is not necessarily completely zero. . The absolute value of acceleration may be reduced to a non-zero value to maintain some velocity change. In this case, after the driving force of the brushless motor 143b is increased when the load is abnormal, the driving force of the brushless motor 143b, which is changed when the load is removed, is changed according to the operating speed when the load is removed. may be different from before the increase in

Further, in the above embodiment, when a load abnormality occurs during a change in speed, the acceleration related to the change is changed. may be controlled to reduce the speed.

Also, in the above embodiment, the load abnormality during speed change at a constant acceleration has been described, but even in the case of load abnormality during acceleration change, the absolute value of acceleration can be temporarily reduced in the same manner. . At the time of returning to the speed change in this case, the correction speed profile may be set so as to gradually decrease the acceleration from a larger absolute value than originally.

Further, in the above embodiment, the correction speed profile is determined so as to compensate for the delay time caused by this interruption when returning after the speed change is interrupted. no. Further, when the absolute value of acceleration related to the corrected speed profile increases, the corrected speed profile may be determined so that the absolute value of acceleration is gradually increased rather than suddenly increased to a specific absolute value.

Further, in the above embodiment, the operation speed information is described as having a plurality of speed tables 1411a and a single acceleration table 1411b, but the present invention is not limited to this. At least one of them should be present.

Further, in the above embodiment, the drive unit 143 has two rotary motors, but the speed change may be temporarily interrupted in the same way even with a single rotary motor. Also, even if there are three or more rotary motors, for example, two support motors may be placed on both sides of the main motor for balance. Moreover, the configuration may be such that drive control is performed on a drive unit having a plurality of combinations of main motors and support motors.

Further, in the above embodiment, the stepping motor and the brushless motor are used as examples of the two rotary motors, but other types of rotary motors may be used. Further, it is not necessary to apply a driving force in the rotational direction, such as a clutch. Also, it may be a motor other than a rotary motor, for example, a motor that reciprocates along a predetermined axis to apply a driving force to the object.

Further, in the above embodiment, the load is detected by measuring the current of the brushless motor 143b, but the load may be detected by measuring the current of the stepping motor 143a.

Further, in the above embodiment, the rotating shaft of the motor is set at a predetermined position and the amount of rotation is detected. may have.

Further, in the above embodiment, the medium to be conveyed is detected by an optical sensor, but other sensors, such as a sensor that detects a change in electric conductivity according to contact with the medium to be conveyed, may be used. Also, the light detected by the optical sensor is not limited to visible light, and may be infrared light or the like.

Further, in the above-described embodiment, the motor that drives the transport roller in the transport unit of the recording medium in the image forming apparatus is described. However, it is not limited to these. The motor may be a motor used in a transport section that transports other members or the like, or may be a motor in a configuration that moves or rotates an object within a predetermined range without being limited to transport.

Further, in the above embodiment, the control circuit 1413 performs various judgments and operation control by a hardware circuit such as an ASIC, but part or all of it may be processed by software such as a CPU.
In addition, specific details such as the configurations, control contents, and control procedures shown in the above embodiments can be changed as appropriate without departing from the spirit of the present invention.

1, 1a, 1b image forming apparatus 11 control unit 111 CPU
112 RAMs
113 storage unit 12 image reading unit 13 forming operation unit 14 transport unit 140 medium transport unit 141 control unit 1411 RAM
1411a Speed table 1411b Acceleration table 1412 Register 1412a Acceleration/deceleration setting 1413 Control circuit 1413a Counting circuit 1414 Input/output I/F
1415 buffer 1416 current control unit 142 drive signal output unit 142a first signal output unit 142b second signal output unit 143 drive units 143a, 143c stepping motors 143a1, 143b1, 143c1 rotary shaft 143b brushless motor 144 load detection units 146, 1461, 1462 Motion detection unit 147 Medium detection unit 15 Storage unit 16 Operation reception unit 17 Display unit 18 Communication unit 19 Bus 21 Counter 22 Logic circuit 23 Flip-flop circuit 201 Transmission shafts 201a, 202, 202a Roller 201a Roller 211 Count set value M Medium

Claims (20)

a storage unit that stores operating speed information of a driving unit that generates a driving force applied to a predetermined object;
a control unit that controls the operating speed of the driving unit based on the operating speed information;
an acquisition unit that acquires a detection result of a load detection unit that detects the load of the drive unit;
with
The control unit changes the operating speed information to change the operating speed when a detection result indicating an abnormality of the load is acquired ,
decreasing the absolute value of the acceleration associated with the change in the operating speed when a detection result indicating that the load is abnormal is acquired during the change in the operating speed;
stopping the reduction of the absolute value of the acceleration and temporarily increasing the absolute value when a detection result indicating that the abnormality of the load has been resolved is acquired;
An operating speed of the driving unit that changes sequentially due to a temporary increase in the absolute value of the acceleration, and an operating speed according to the change determined by the operating speed information before acquisition of a detection result indicating an abnormality in the load. terminating the temporary rise when equal to the assumed value of
When the detection result indicating that the load abnormality has been resolved is obtained, the driving unit is operated within a period in which the operation speed is scheduled to be changed according to the operation speed information before the detection result indicating the load abnormality is obtained. Determine the temporary increase amount of the absolute value of the acceleration so that the operating speed of and the assumed value are equal
A drive control device characterized by: the operation speed information includes an array of speed index values related to the operation speed of the drive unit;
When changing the operating speed of the driving unit, the control unit sequentially changes the operating speed in accordance with the arrangement order of the speed index values, and a detection result indicating an abnormality of the load is detected during the change of the operating speed. 2. The drive control device according to claim 1, wherein, when obtained, the absolute value of the acceleration associated with the change in the operating speed is decreased. 3. The drive control according to claim 1, wherein the control unit interrupts the change of the operating speed when a detection result indicating an abnormality of the load is obtained during the changing of the operating speed. Device. The drive control device according to any one of claims 1 to 3 , wherein the drive section includes a first drive section and a second drive section that generate the drive force applied to the same target. . 5. The drive control device according to claim 4 , wherein the second driving section transmits the driving force to the same transmission shaft as the first driving section. The control unit is capable of adjusting the driving force transmitted from the second driving unit to the transmission shaft,
6. The drive control device according to claim 5 , wherein the drive force of the second drive section is increased when a detection result indicating an abnormality of the load is obtained. The control unit equalizes the operation speed of the first driving unit and an assumed value of the operation speed according to the change determined by the operation speed information before acquisition of the detection result indicating the abnormality of the load. 7. The drive control device according to claim 6 , wherein the increase in the driving force is terminated when the driving force becomes. 5. The drive control device according to claim 4 , wherein said first drive section and said second drive section individually apply drive force to said object. 9. The drive control device according to claim 8 , wherein the control section controls the operating speed of the first driving section and the operating speed of the second driving section based on the same operating speed information. The acquisition unit acquires detection results of an operation amount detection unit that detects an operation amount at a predetermined position corresponding to each operation of the first drive unit and the second drive unit,
When the movement amount detection section detects a change in the movement speed of one of the first drive section and the second drive section, the control section changes the movement speed information to a magnitude corresponding to the change. 10. The drive control device according to claim 8 or 9, wherein the operating speed of the first driving unit and the operating speed of the second driving unit are adjusted to match each other. 11. The drive control device according to claim 10 , wherein the operation amount detection section has an encoder. The acquisition unit acquires a detection result of a target detection unit that detects a movement state of the target in a predetermined direction,
The first driving section and the second driving section apply a driving force to the object at positions aligned in a direction perpendicular to the predetermined direction, and move the object in the predetermined direction according to the operating speed. move at the specified speed,
The control unit identifies an inclination of the object with respect to the predetermined direction based on the detection result of the object detection unit, and controls the first driving unit and the second driving unit so that the identified inclination is removed. The drive control device according to any one of claims 8 to 11, wherein the operating speed of at least one of the parts is modified. The target detection unit has a plurality of sensors capable of detecting the presence or absence of the target,
The sensors are arranged in parallel in a direction perpendicular to the predetermined direction,
13. The drive control device according to claim 12 , wherein the control unit identifies the inclination according to a difference in detection timing of the object by the plurality of sensors. 14. The drive control device according to claim 13 , wherein the plurality of sensors are optical sensors. The drive control device according to any one of claims 4 to 14, wherein the load detection section measures the current supplied to the second drive section. The drive control device according to any one of claims 4 to 15, wherein the first drive section and the second drive section have rotary motors. 17. The drive control device according to claim 16 , wherein said second drive section has a brushless motor. 17. The drive control device according to claim 16 , wherein said second drive section has a stepping motor. a driving unit that produces a force to be transmitted to a predetermined target;
a load detection unit that detects the load of the driving unit;
A drive control device according to any one of claims 1 to 18 ;
a transport section comprising
an image forming operation unit that forms an image on the medium conveyed by the conveying unit;
An image forming apparatus comprising: A drive control method for a drive unit by a drive control device having a storage unit for storing operating speed information of the drive unit that generates a driving force applied to a predetermined object,
a control step of controlling the operating speed of the drive unit based on the operating speed information;
an acquisition step of acquiring a detection result of a load detection unit that detects the load of the driving unit;
including
In the control step, when a detection result indicating an abnormality of the load is acquired, the operating speed information is changed to change the operating speed ,
decreasing the absolute value of the acceleration associated with the change in the operating speed when a detection result indicating that the load is abnormal is acquired during the change in the operating speed;
stopping the reduction of the absolute value of the acceleration and temporarily increasing the absolute value when a detection result indicating that the abnormality of the load has been resolved is acquired;
An operating speed of the driving unit that changes sequentially due to a temporary increase in the absolute value of the acceleration, and an operating speed according to the change determined by the operating speed information before acquisition of a detection result indicating an abnormality in the load. terminating the temporary rise when equal to the assumed value of
When the detection result indicating that the load abnormality has been resolved is obtained, the driving unit is operated within a period in which the operation speed is scheduled to be changed according to the operation speed information before the detection result indicating the load abnormality is obtained. Determine the temporary increase amount of the absolute value of the acceleration so that the operating speed of and the assumed value are equal
A drive control method characterized by:

Images