JP4454887B2 - Motor control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a motor control device that controls rotation / stop of a motor .
[0002]
[Prior art]
In recent years, an outer rotor type brushless motor is mainly used as a drive source for paper conveyance in an image forming apparatus. Outer rotor type brushless motors are widely used because they are inexpensive and can be used with high efficiency in a relatively high rotation range.
[0003]
Recently, the drive system is often divided and independent brushless motors are used depending on the load.
[0004]
However, the outer rotor type brushless motor has a demerit that the inertia is large and the rotor inertia continues to rotate even after the electrical stop signal is applied when stopping from the rotating state, and it takes time until the motor stops completely.
[0005]
When a paper jam occurs due to some problem when the paper is transported by the image forming operation in the image forming apparatus, the time until this complete stop is the time to transport the jammed paper forcibly, and the mechanism is subjected to excessive stress. There is a case to call. For example, when a paper jams into the fixing / separating claw, the paper will push the fixing / separating claw unless the paper transport is immediately stopped. As a result, the fixing separation claw may pierce the fixing roller and damage the fixing roller.
[0006]
Therefore, there is short brake control as a short-time stop control method of the motor, but in the case of a brushless motor, the rotor is not electrically connected like a brush motor, but is only turned by electromagnetic force. So it is not as effective as a brush motor.
[0007]
In addition, as a method of stopping the motor in a shorter time, there is reverse brake control. In this case, if the application time of the reverse signal is not adapted to the inertia and the load, there is a possibility that the motor will reverse beyond the stop.
[0008]
[Problems to be solved by the invention]
Therefore, it is necessary to set the application time of the reverse rotation signal to such an extent that the reverse rotation motor does not reverse in any load state. However, if the reverse rotation signal is too short, the reverse brake control is stopped when the rotor is not completely stopped, so the rotor becomes free and it takes time until the complete stop. It may induce unforeseen circumstances.
[0009]
The present invention has been made in view of the above-described situation. When there is a load change due to long-term use or a load variation among devices, the reverse brake signal application time of the motor is fixed and variable. Even if not, it is an object of the present invention to provide a motor control device that can always achieve a constant reverse braking effect and a complete stop by a short brake with a simple configuration .
[0010]
[Means for Solving the Invention]
This invention can solve the said subject by providing the following structure.
[0011]
(1) A start / stop signal for controlling the operation / non-operation of the motor, a forward / reverse signal for controlling the rotation direction of the motor, the motor rotor of the motor being left free, or a stator coil being short-circuited to the motor A motor control device having a motor control IC for controlling the motor in response to a no-brake / short-brake signal for controlling whether to apply a short brake to the motor, and a motor rotation / stop command signal input to the motor control device , said a first signal line for supplying the forward / reverse rotation signal input terminal of the motor control IC, and the signal supplied to the forward / reverse rotation signal input terminal, a first set time predetermined by a delay element only delays the second signal line for supplying a no brake / short brake signal terminals of the motor control IC The signal supplied to the no-brake / short brake signal terminal, a third signal line supplying delayed by a second set time predetermined for the start / stop signal terminals of the motor control IC by delay element Yes motor control device characterized by.
[0012]
(2) the first setting time between, the motor of the forward state is equal to or shorter than time to start to rotate in the opposite direction by the reverse rotation signal (1) The motor control device according.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0017]
FIG. 1 is a schematic cross-sectional view showing a configuration of an image forming apparatus equipped with a sheet processing control method according to the present invention.
[0018]
Reference numeral 101 denotes an original platen glass on which originals fed from the automatic document feeder 160 are sequentially placed at predetermined positions. Reference numeral 102 denotes a document illumination lamp composed of, for example, a fluorescent lamp, which exposes a document placed on the document table glass 101. Scanning mirrors 103, 104, and 105 are accommodated in an optical scanning unit (not shown) and guide reflected light from the original to the CCD unit 106 while reciprocating.
[0019]
The CCD unit 106 includes an imaging lens 107 that forms an image of reflected light from a document on the CCD, for example, an image sensor 108 composed of a CCD, a CCD driver 109 that drives the image sensor 108, and the like.
[0020]
The image signal output from the image sensor 108 is converted into, for example, 8-bit digital data and then input to the controller unit 150.
[0021]
Reference numeral 110 denotes a photosensitive drum, which is discharged by a pre-exposure lamp 112 in preparation for image formation. A primary charger 113 uniformly charges the photosensitive drum 110. Reference numeral 117 denotes an exposure unit, which is composed of, for example, a semiconductor laser and exposes the photosensitive drum 110 based on image data processed by the controller unit 150 that performs image processing and overall control of the apparatus, thereby forming an electrostatic latent image. .
[0022]
Reference numeral 118 denotes a developing device that contains a black developer (toner). Reference numeral 119 denotes a buffer unit that stores toner, and the toner is supplied from a removable toner storage container (hereinafter referred to as a toner cartridge) 120 set at an upper position. The toner supplied to the buffer unit 119 is supplied to the developing device 118 according to the amount of toner in the developing device 118. A pre-transfer charger 121 applies a high voltage before the toner image developed on the photosensitive drum 110 is transferred to a sheet.
[0023]
Reference numerals 122, 124, 126, 128, and 130 denote paper feed units, and each paper feed roller 123, 125, 127, 129, 131 drives the transfer paper into the apparatus, and the registration roller 132 is disposed. Is temporarily stopped, the writing timing with the image formed on the photosensitive drum 110 is taken, and the sheet is fed again.
[0024]
Reference numeral 133 denotes a transfer charger, which transfers the toner image developed on the photosensitive drum 110 onto a transfer sheet to be fed. A separation charger 134 separates the transfer sheet on which the transfer operation has been completed from the photosensitive drum 110. Reference numeral 170 denotes a separation claw for physically separating the transfer paper when electrostatic separation by the separation charger 134 is not successful.
[0025]
The toner remaining on the photosensitive drum 110 without being transferred is collected by the cleaner 111.
[0026]
Reference numeral 135 denotes a conveyance belt which conveys the transfer sheet on which the transfer process has been completed to the fixing device 136 and is fixed by heating, for example. Reference numeral 137 denotes a flapper, which controls the transfer sheet transport path after the fixing process in either the staple sorter 145 direction or the reverse path 139 direction. The sheets discharged to the staple sorter 145 are sorted into bins, and the staple unit 146 performs stapling according to instructions from the controller unit 150. The reverse path 139 is used when face-down paper discharge and double-sided copying. When face-down paper discharge is performed, the paper is reversed after the reverse path 139 and discharged. When performing double-sided copying, the paper is conveyed from the reverse path 139 to the double-sided path 144. Reference numerals 140 to 142 denote paper feed rollers that convey the retransfer paper on the duplex path 144 to the refeed roller 143. The retransfer paper is conveyed by the paper feed rollers 140 to 142 and the refeed roller 143 in a timed manner with the transfer paper fed from the paper feed units 122, 124, 126, 128, and 130. It is conveyed to the installation position.
[0027]
The controller unit 150 includes a microcomputer, an image processing unit, and the like, which will be described later, and performs the above-described image forming operation in accordance with instructions from the operation panel 151.
[0028]
Further, a temperature / humidity sensor (not shown) for detecting the temperature and humidity in the image forming apparatus is provided.
[0029]
FIG. 2 is a block diagram showing the configuration of the controller unit 150 of the image forming apparatus according to the present invention.
[0030]
A CPU 201 controls the entire image forming apparatus, and sequentially reads and executes a program from a read-only memory (ROM) 203 that stores a control procedure (control program) of the apparatus main body. The address bus and data bus of the CPU 201 are connected to each load via a bus driver and an address decoder 202.
[0031]
Reference numeral 204 denotes a random access memory (RAM) which is a main storage device used for storing input data, a working storage area, and the like.
[0032]
Reference numeral 205 denotes an image data hard disk (HD) which stores data input from the CCD unit 106 and subjected to image processing. The image data is also stored when connected to a network or the like.
[0033]
Reference numeral 206 denotes an I / O port conforming to the interface standard. The operator inputs a key and displays an operation panel 151 for displaying the state of the apparatus using a liquid crystal (LED), a paper feed system, a transport system, and an optical system. The motors 207, the clutches 208, the solenoids 209, and the paper detection sensors 210 for detecting the conveyed paper are connected to each load of the apparatus.
[0034]
The developing device 118 is provided with a toner sensor 211 that detects the amount of toner in the developing device, and its output signal is input to the I / O port 206. In addition, signals from switches 212 for detecting the home position of each load, the open / closed state of the door, and the like are also input to the I / O port 206. A high voltage unit 213 outputs a high voltage to the above-described primary charger 113, developing device 118, pre-transfer charger 121, transfer charger 133, and separation charger 134 in accordance with instructions from the CPU 201.
[0035]
An output from a temperature / humidity sensor (not shown) is directly connected to an analog port of the CPU 201, and is A / D converted and calculated as a digital value. From the temperature / humidity sensor, a voltage value representing temperature and a voltage value representing humidity are input to the analog port of the CPU 201.
[0036]
An image processing unit 215 receives an image signal output from the CCD unit 106, performs image processing described later, and outputs a control signal for the laser unit 117 according to the image data.
[0037]
Laser light output from the laser unit 117 irradiates and exposes the photosensitive drum 110, and a light emission state is detected by the beam detection sensor 214 which is a light receiving sensor in the non-image area, and the output signal is output from the I / O port 206. Is input.
[0038]
FIG. 3 is a block diagram showing a configuration of the image processing unit 215 in the controller unit 150 in the image forming apparatus according to the present invention.
[0039]
The image signal converted into an electrical signal by the CCD 108 is first corrected for variation among pixels by the shading circuit 301, and then subjected to a data thinning process at the time of reduction copy at the scaling circuit 302, and at the time of enlargement copy, the data Perform interpolation.
[0040]
Next, in the edge enhancement circuit 303, for example, secondary differentiation is performed in a 5 × 5 window to enhance the edge of the image. Since this image data is luminance data, the γ conversion circuit 304 performs data conversion by table search in order to convert the image data into density data for output to the print. The image data converted into density data is input to the binarization processing unit 305. Here, for example, multi-value data is converted into binary data by the ED method. The image data converted to binary is input to the synthesis circuit 307. The combining circuit 307 selectively outputs the input image data and the image data in the image memory 310 constituted by, for example, a hard disk, or outputs the result of ORing. The read / write control for the image memory 310 is performed by the memory controller 306, and when the image is rotated, the read address of the image data in the memory is controlled. These image data are input to the PWM circuit 311 to be converted into a signal of laser emission intensity, and a pulse width corresponding to the image density is output to the laser unit 117.
[0041]
Next, FIG. 4 is a schematic explanatory view showing an image forming process, which will be described with reference to FIG.
[0042]
The photosensitive drum 110 rotates in the direction of the arrow (clockwise).
[0043]
Residual charges on the surface of the photosensitive drum 110 are removed by the pre-exposure unit and then charged to 700 to 800 V by the primary charger 113. Thereafter, the image is exposed, and a rectangular wave of about 1500 Vpp and a DC bias of 0 to 500 V are applied to the developing device 118 to form a toner image on the latent image on the surface of the photosensitive drum 110. Next, a rectangular wave of 12,500 Vpp and a DC constant current of 0 to 500 μA are applied by the pre-transfer charger 121 so that the toner image on the photosensitive drum 110 is easily transferred. The transfer charger is applied with a negative potential of −5300V to −8300V to transfer the toner image onto the transfer paper.
[0044]
The separation charger 134 is applied with a rectangular wave of 14000 Vpp and a DC constant current of 0 to 500 μA to separate the transfer paper from the photosensitive drum 110.
[0045]
The transfer paper on which the toner image has been transferred and separated from the photosensitive drum 110 is heated and pressurized and fixed by a fixing device 136. The toner that has not been transferred on the photosensitive drum 110 is cleaned by a cleaner blade, and again proceeds to the pre-exposure process.
[0046]
The above is the description of the image forming process.
[0047]
Next, the actual operation will be described.
[0048]
FIG. 5 is an enlarged explanatory view of the fixing unit in FIG. In the drawing, the fixing roller is divided into an upper fixing roller 136u and upper and lower rollers of a pressure roller 136L, and is heated and pressed and fixed. The upper fixing roller 136u is driven by a fixing driving motor (not shown) independently of the other driving, and the pressure roller 136L is driven to rotate by the driving of the upper fixing roller 136u. After exiting the pair of fixing rollers 136u and 136L, a fixing separation claw 1361, a claw jam sensor 1362, an internal paper discharge roller 1363, and an internal paper discharge sensor 1364 are arranged.
[0049]
FIG. 6 is an explanatory diagram showing how a sheet (paper) is separated by a fixing separation claw.
[0050]
FIG. 7 is a perspective view showing the positional relationship between the fixing separation claw and the fixing upper roller.
[0051]
FIG. 8 is an explanatory diagram showing a state in which a sheet (paper) is caught on the fixing separation claw.
[0052]
As shown in FIG. 6, the fixing separation claw 1361 is provided to physically separate the paper adhering to the fixing upper roller 136u with the claw. As shown in the perspective view of FIG. There are 6 locations. If the leading edge of the paper is caught in any of the six fixing separation claws 1361, the separation claw 1361 not caught is forcibly pressed against the fixing upper roller 136u side by the paper as shown by the arrow in FIG. It will be. In this case, the fixing separation claw 1361 digs into the fixing upper roller 136u or scratches the fixing upper roller, and as a result, only that portion cannot be fixed. If this happens, the fixing upper roller 136u must be replaced, which is a major obstacle for the user.
[0053]
Therefore, as shown in the basic timing chart of the reverse brake control in FIG. 9, a reverse signal for reversing the motor rotation direction is applied before the motor stop signal (the reverse signal application time is tc). A method of applying a reverse rotation signal and applying a brake when stopping the motor in this way is called reverse brake control.
[0054]
However, in actuality, the amount of inertia rotation from the motor stop command varies depending on the variation in load and the change in the friction coefficient of the sliding portion due to long-term use.
[0055]
10 and 11 are timing charts showing the difference.
[0056]
FIG. 10 is a timing chart showing the stop time when the sliding load is relatively light when the reverse brake control is not used. The inertia rotation by the rotor inertia has been stopped for t1 hours from the motor stop command.
[0057]
FIG. 11 is a timing chart showing the stop time in a state where the use of the reverse brake control is not used for a long time and the sliding load becomes heavy. The inertia component is determined by the physical shape and is irrelevant to whether or not it is used for a long time. However, as the sliding load increases with long-term use, the braking effect is enhanced and the time to stop is shortened.
[0058]
If the reverse brake application time is set to the time for the minimum load, if the load increases, it may stop too early and cause reverse rotation. This is shown in FIG.
[0059]
That is, FIG. 12A is a timing chart showing a case where the reverse brake application time is too long and the reverse rotation is reached.
[0060]
In order to prevent reverse rotation for such load variations, the reverse brake application time is set to the shortest stop time.
[0061]
However, in that case, when the load is light, the reverse brake is released before the time until the rotor completely stops, and the rotor does not completely stop. This is shown in FIG.
[0062]
That is, FIG. 12B is a timing chart illustrating a case where the reverse brake application time is too short to completely stop the rotor.
[0063]
FIG. 13 is a timing chart showing the sheet processing control method according to the present invention, and FIG. 14 is a controller and motor control circuit for realizing the timing chart of FIG.
[0064]
Therefore, as shown in FIG. 13, the short brake mode is switched to the reverse rotation time after the reverse brake signal is applied to prevent reverse rotation as shown in FIG. 12B after the reverse brake is released.
[0065]
FIG. 14 is a circuit diagram for realizing the timing chart of FIG. Reference numeral 150 in FIG. 14 denotes a DC controller that forms the controller unit described in FIG. 2 (hereinafter referred to as a DC controller). A motor control IC 1301 controls the motor. The first pin of the motor control IC 1301 is a start / stop terminal, the second pin is a forward / reverse rotation terminal, and the third pin is a brake terminal. The start / stop terminal starts at L, stops at H or open, and the forward / reverse terminal is forward at L or open, and reverse at H. The brake terminal is L or open, no brake, and H when brake. Pin 8 is a lock detection signal, which outputs L when the motor is within the rated speed ± 6%. Reference numerals 1302 to 1304 denote hall elements that output an alternating waveform corresponding to the pattern magnetized on the motor rotor. An FG output signal is generated by combining the outputs of the Hall elements 1302-1304. 1414 of 1301 is the FG output.
[0066]
The DC controller 150 outputs a rotation / stop * command signal to the motor. Further, the motor outputs an FG pulse signal and a lock detection signal to the DC controller 150. Reference numeral 1305 denotes a motor drive element, and 1306 denotes a motor stator coil.
[0067]
14, φ1, φ2, φ3, and φ4 correspond to the rotation / stop * command signal, FORWARD / BACK * signal, No Break / Short Break * signal, and start / stop * signal in FIG. 13, respectively. Here, a signal name with an asterisk (*) is a low and active signal, and a signal name not added is a high and active signal. The rotation / stop * command signal output from the DC controller becomes the forward / reverse * signal as it is. Also, the rotation / stop * command signal delayed by the delay element 1307 becomes the FORWARD / BACK * signal, and the FORWARD / BACK * signal delayed by the delay element 1308 becomes the start / stop * signal.
[0068]
When a motor rotation command is received from the DC controller 150, first, the forward / reverse rotation signal is switched to forward rotation at T1. At this point, the motor has not yet rotated. Next, the short brake is released at T2. Actually, the short brake does not work unless the motor start signal is input, so the rotor is in a free state.
[0069]
Next, at T3, the start / stop * signal is started, and the motor starts to rotate in the forward direction.
[0070]
Next, the stop time will be described. When a motor stop command is received, the rotation direction signal is switched to reverse at T4. At this time, the short brake is not in the brake state, and the motor is in the start state, so the reverse brake is applied. Next, after a delay of tc1, the short brake signal becomes a short brake at T5. Regardless of the logic of the reverse rotation signal, if the short brake signal is in the short brake state and the start / stop signal is in the start state, the short brake mode is set. After tc2 from T5, the start / stop signal is stopped, and the motor brake is not applied.
[0071]
tc1 is the reverse brake application time, and tc2 is the short brake application time.
[0072]
FIG. 15 is a timing chart in which the reverse brake start edge of FIG. 13 is delayed to create a short brake start edge, and the short brake start edge is delayed to a stop signal edge.
[0073]
15 is a timing chart showing the sheet processing control method according to the present invention. FIG. 16 shows a controller and motor control circuit for realizing the timing chart of FIG.
[0074]
【The invention's effect】
As described above, according to the present invention, when there is a load change due to long-term use or a load variation among devices, the application time of the reverse brake signal of the motor is fixed and not variable. However, a constant reverse braking effect and a complete stop by a short brake are always possible.
[0075]
That is, in the present invention, the conventional problem is solved by generating a signal so that the short brake state is established from the time when the reverse brake signal is released.
In addition, the forward / reverse rotation signal, no-brake / short-brake signal, and start / stop signal are generated from the motor rotation / stop command signal without depending on the processing of the CPU. Can be realized with a simple configuration to decelerate the motor and then stop the motor by a short brake.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view illustrating a configuration of an image forming apparatus equipped with a sheet processing control method according to the present invention. FIG. 2 is a block diagram illustrating a configuration of a controller unit 150 of the image forming apparatus according to the present invention. FIG. 4 is a block diagram showing a configuration of an image processing unit 215 in the controller unit 150 in the image forming apparatus according to the present invention. FIG. 4 is a schematic explanatory view showing an image forming process. FIG. FIG. 6 is an explanatory view showing how a sheet (paper) is separated by a fixing separation claw. FIG. 7 is a perspective view showing a positional relationship between the fixing separation claw and a fixing upper roller. ) Is an explanatory diagram showing the hooked state. [Fig. 9] Basic timing chart of reverse brake control. [Fig. 10] The stop time when the sliding load is relatively light (initial use) when reverse brake control is not used. Timing chart shown [FIG. 11] Timing chart showing stop time in a state where the use of the reverse brake control is not used for a long time and the sliding load becomes heavy (late use) [FIG. 12] (a ) Timing chart showing the case where the reverse brake application time is too long and the reverse rotation is reached, (b) Timing chart showing the case where the reverse brake application time is too short to stop the rotor completely [FIG. 13] FIG. 14 is a control circuit diagram of a controller and a motor for realizing the timing chart of FIG. 13. FIG. 15 is a timing chart showing the sheet processing control method according to the present invention. FIG. 16 is a timing chart in the case where the timing chart is delayed. Control circuit diagram of the over La and motor [Description of symbols]
DESCRIPTION OF SYMBOLS 101 Document glass 102 Document illumination lamps 103, 104, 105 Scanning mirror 106 CCD unit 107 Imaging lens 108 Imaging element 109 CCD driver 110 Photosensitive drum 111 Cleaner 112 Pre-exposure lamp 113 Primary charger 117 Exposure means (laser unit)
118 Developing Device 119 Buffer 120 Toner Cartridge (Removable Toner Storage Container)
121 Pre-transfer chargers 122, 124, 126, 128, 130 Paper feed unit 150 Controller (DC controller)
123, 125, 127, 129, 131 Paper feeding roller 132 Registration roller 133 Transfer charging device 134 Separation charging device 135 Conveying belt 136 Fixing device 137 Flapper 139 Reverse path 140-142 Paper feeding roller 143 Re-feed roller 144 Double-sided path 145 Staple Sorter 146 Stapling section 151 Operation panel 170 Separation claw 160 Automatic document feeder 201 CPU
202 Bus driver and address decoder 203 ROM
204 RAM
205 Hard disk for image data (HD)
206 I / O port 207 Motor 208 Clutch 209 Solenoid 210 Paper detection sensor 211 Toner sensor 212 Switch 213 High voltage unit 214 Beam detection sensor 215 Image processing unit 301 Shading circuit 302 Scaling circuit 303 Edge enhancement circuit 304 γ Conversion circuit 305 Binary processing unit 306 Memory controller 307 Synthesis circuit 310 Image memory 311 PWM circuit 1301 Motor control IC
1302-1304 Hall element 1305 Motor drive element 1306 Motor stator coil 1307, 1308 Delay element 136u Upper fixing roller 136L Pressing roller 1361 Fixing separation claw 1362 Claw jam sensor 1363 Internal paper discharge roller 1364 Internal paper discharge sensor

Claims (2)

Start / stop signal for controlling the operation / non-operation of the motor, forward / reverse signal for controlling the rotation direction of the motor, freeing the motor rotor of the motor, or short-circuiting the stator coil to short brake to the motor A motor control device having a motor control IC for controlling the motor in response to a no-brake / short-brake signal for controlling whether to apply
A first signal line for supplying a motor rotation / stop command signal input to the motor control device to a forward / reverse signal input terminal of the motor control IC ;
The signal supplied to the forward / reverse rotation signal input terminal, a first second signal line for supplying the set time only delays a no brake / short brake signal terminals of the motor control IC, which is predetermined by the delay element And
Yes said signals supplied to the No brake / short brake signal terminal, the third signal line supplying delayed by a second set a predetermined time by the delay element to the start / stop signal terminals of the motor control IC A motor control device.   2. The motor control device according to claim 1, wherein the first set time is shorter than a time until the motor in the normal rotation state starts to rotate in the reverse direction by the reverse rotation signal.

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