JP5380009B2 - STEPPING MOTOR DEVICE, PAPER CONVEYING DEVICE, AND IMAGE FORMING DEVICE - Google Patents

Description

  The present invention relates to a stepping motor device, a sheet conveying device, and an image forming apparatus, and in particular, a stepping motor device in which the rotation directions of a plurality of stepping motors are restricted, a sheet conveying device using the stepping motor device, and an image forming apparatus. About.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, a stepping motor is used to drive a paper conveying device that conveys paper such as a document or printing paper. FIG. 7 is a diagram showing a schematic configuration of the stepping motor. Referring to FIG. 7, a stepping motor 50 includes four stators (electromagnets) 51 facing each other, and a rotor (permanent magnet) 52 that is provided inside the stator 51 and rotates according to a magnetic field generated in the stator 51. Including. The center of the rotor 52 is connected to the motor shaft 53. The stepping motor 50 rotates the motor shaft 53 by applying a pulsed voltage continuously and switching the positional relationship between the stator 51 and the rotor 52. In the stepping motor, if the pulse voltage is suddenly applied when the positional relationship between the stator 51 and the rotor 52 is deviated due to the structure of the motor, the rotor 52 cannot move to the intended position, and a phenomenon of step-out occurs at startup. To do.

In order not to cause such a step-out phenomenon, control is performed in which DC excitation (hold) is performed for a certain period of time so as to match the positional relationship between the stator 51 and the rotor 52 and the positional relationship is matched. Such control is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2001-292597 (Patent Document 1), Japanese Unexamined Patent Application Publication No. 2002-366002 (Patent Document 2), and Japanese Unexamined Patent Application Publication No. 2002-366001 (Patent Document 3). Has been.
JP 2001-292597 A (summary) JP 2002-366002 A (summary) JP 2002-366001 A (summary)

  The conventional method for preventing the step-out at the start of the stepping motor has been performed as described above. In the conventional example, there is no problem because one drive train is composed of one motor as a drive source, and direct current excitation (hereinafter referred to as “hold”) is performed in an arbitrary rotation direction for a certain period of time. In an apparatus in which two or more motor shafts are each configured as an independent drive train, in order to improve user operability, when these are connected by a connected object such as a belt, the direction is constant. Even when trying to hold DC excitation for a long time, there is a problem that the connected object interferes and the intended operation cannot be performed.

  The present invention has been made paying attention to the above-described problems, and even when the motor shafts of a plurality of stepping motors are connected by a connected object and the rotation direction thereof is restricted, It is an object of the present invention to provide a stepping motor device that can be individually held.

An image forming apparatus according to the present invention includes a pair of stepping motors, a coupling unit that couples the pair of stepping motors to rotate in the same direction, and a stator that constitutes the stepping motor to prevent the pair of stepping motors from stepping out. and a hold means for performing a hold for adjusting the positional relationship between the rotor, the one of the pair of stepper motors, when it is rotated by the connecting means, so as to rotate only in one direction, connected to the connecting means The hold means rotates the rotor of one stepping motor in one direction to perform DC excitation for a fixed time, and then rotates the other stepping motor in the reverse direction to perform DC excitation for a fixed time.

  The holding means preferably maintains the hold state of one stepping motor until the other stepping motor is held.

  In another aspect of the present invention, the sheet conveying device uses the above stepping motor device.

  In still another aspect of the present invention, an image forming apparatus includes the above-described sheet conveying device.

  According to the present invention, one of the pair of stepping motors is connected to the connecting means so as to rotate only in one direction when rotated by the connecting means. Accordingly, even if the rotor of one stepping motor is DC-excited for a certain period of time and then held by rotating the rotor of the other stepping motor in the reverse direction, the hold position of one stepping motor does not change.

  As a result, even when the rotors of a plurality of stepping motors are connected by a connected object, a stepping motor device that can hold each motor individually can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a digital multi-function peripheral when the stepping motor apparatus according to one embodiment of the present invention is applied to a paper transport device of the digital multi-function peripheral. Here, the document feeder 14 is a paper transport device.

  Referring to FIG. 1, a digital multifunction peripheral 10 displays a control unit 11 that controls the entire digital multifunction peripheral 10, a DRAM 12 for writing and reading image data and the like, and information that the digital multifunction peripheral 10 has. An operation unit 13 that includes a display screen and serves as an interface with a user in the digital multifunction peripheral 10; a document feeder 14 that includes an image reading unit 15 that conveys a document and reads the conveyed document with a scanner at a reading position; An image forming unit 16 that forms an image from a document read by the image reading unit 15 and outputs the image, a hard disk (HD) 17 that stores image data and the like, and a FAX communication unit 18 connected to the public line 20. And a network IF (interface) unit 19 for connecting to the network 21.

  The document feeder 14 includes a stepping motor device 31 including a plurality of stepping motors 26 to 28 for conveying the document and a hold device (hold means) 30 for holding the stepping motors 26 to 28.

  The digital multifunction peripheral 10 operates as a copying machine by forming an image in the image forming unit 16 via the DRAM 12 using the image data of the original read by the image reading unit 15. Further, the digital multifunction peripheral 10 forms an image in the image forming unit 16 via the DRAM 12 using the image data transmitted from the personal computer 22 connected to the network 21 through the network IF unit 19, thereby serving as a printer. Operate. Further, the digital multifunction peripheral 10 forms an image in the image forming unit 16 through the DRAM 12 using the image data transmitted from the public line 20 through the FAX communication unit 18, and also by the image reading unit 15. The image data of the read original is transmitted to the public line 20 through the FAX communication unit 18 to operate as a facsimile machine. That is, the digital multi-function peripheral 10 has a plurality of functions such as a copying (copying) function, a printer function, and a FAX function regarding image processing. Further, each function has functions that can be set in more detail.

  In FIG. 1, thick arrows indicate the flow of image data, and thin arrows indicate the flow of control signals or control data.

  The control unit 11 compresses and writes the image data of the original document supplied from the image reading unit 15 to the DRAM 12, reads the data written to the DRAM 12, decompresses and decodes the data, and outputs it by the image forming unit 16.

  FIG. 2 is a diagram showing details of the document feeder 14. The solid arrow in FIG. 2 indicates the conveyance direction when reading one side of the document, and the dotted arrow indicates the conveyance direction when reading the other side. 1 to 2, the document feeder 14 feeds a document tray 25 on which a document to be conveyed is set and a document set on the document tray 25 one by one to the document to a predetermined position. A paper feed roller 26a for transporting, a transport roller 27a for transporting a document transported to a predetermined location by the paper feed roller 26a, and an image reading unit 15 for reading an image of the document transported by the transport roller 27a at a reading position 15a. A reversing roller 28a for holding the document read at the reading position 15a of the image reading unit 15 for reversal, and a discharge roller 29a for discharging the document after reading the reversed document through the reversing roller 28a. And a discharge tray 32 on which the document discharged by the discharge roller 29a is placed. Idle rolls 28b and 29b abut against the reversing roller 28a and the discharge roller 29a, respectively, and the document is conveyed between the rollers. The paper feed roller 26a and the transport roller 27a are driven by the paper feed motor 26 and the transport motor 27, respectively. The reverse roller 28a and the discharge roller 29a are driven by the same reverse motor 28. The reverse motor 28 is attached to the motor shaft of the discharge roller 29a and rotates the discharge roller 29a. The reverse roller 28a and the discharge roller 29a rotate in opposite directions.

  These motors 26 to 28 are all stepping motors that control forward / reverse rotation by pulse drive. When the document is conveyed in the direction indicated by the solid line, the paper feed roller 26a, the conveyance roller 27a, and the reverse roller 28a are rotated in the direction indicated by the solid line, respectively, and when the document is conveyed in the direction indicated by the dotted line, the document is reversed. The roller 28a is rotated in the direction indicated by the dotted line.

  FIG. 3 is a view showing a state where a document jam occurs in the document feeder 14 shown in FIG. A state where the roller is engaged with the conveying roller 27a and the reverse roller 28a is indicated by a dotted line, and a state where the roller is engaged with the conveying roller 27a and the discharge roller 29a is indicated by a one-dot chain line. The drive trains of the respective motors are transport drive by the transport motor 27 and reverse / discharge drive by the reverse motor 28. Since the conveyance drive and the reverse / discharge drive are composed of independent motors 27 and 28, respectively, it is basically necessary to rotate them individually. However, in such a state that the document is jammed and jammed, as shown in FIG. 3, when the conveying roller 27a rotates clockwise, the reverse roller 28a rotates counterclockwise and the discharge roller 29a rotates clockwise. By providing a mechanism for rotating the document, it is possible to easily take out the jammed document.

  FIG. 4 is a diagram for explaining this mechanism. With reference to FIG. 4, in this embodiment, a drive unit 27 b of the conveyance motor 27 that rotates the conveyance roller 27 a and a motor shaft 29 c of the reverse motor are connected by a belt 33. Therefore, the belt 33 operates as a connecting means. An idle roller 34 is provided so that the belt 33 is wound around each roller at a predetermined winding angle. In this case, the transport roller 27a and the discharge roller 29a driven by the reverse motor 28 rotate in the same direction and rotate in the opposite direction to the reverse roller 28a. Then, by rotating in either direction, the jammed original can be easily removed.

  Next, the hold performed by the hold device 30 when the transport motor 27 and the reverse motor 28 are started will be described. Here, the relationship between the driving force of the conveyance motor 27 and the reverse motor 28 is as follows.

Reversing / discharging driving force (by reversing motor 28) <conveying driving force (by conveying motor 27)
In this case, first, the rotor (52 in FIG. 7) of the transport motor 27 is adjusted and held. Thereafter, even if the reversing motor 28 is held, the rotor cannot be moved to a desired position because the reversing motor 28 is connected to the transport motor 27 by the belt 33. Therefore, in this embodiment, as shown in FIG. 4, the drive unit 27b of the carry motor 27 and the drive shaft 27c of the carry motor 27 can rotate only in the clockwise direction in FIG. It is connected via a one-way clutch 35. With this configuration, as shown in FIG. 5, the transport motor 27 and the reverse motor 28 can rotate simultaneously in the clockwise direction, but the transport motor 27 does not rotate in the counterclockwise direction ( Only the reversing motor 28 can rotate and can be held.

  Next, the holding of the reversing motor 28 and the conveyance motor 27 will be described. FIG. 6 is a timing chart of the hold. Here, REM is an abbreviation for the REMOTE signal, the hold process is turned on at the rising edge, and the processing is terminated at the falling edge. CLOCK is a pulse signal for rotating the rotor, _CW / CCW is a signal indicating the clockwise direction or the counterclockwise direction, and the downward direction indicates the clockwise direction. The motor shaft behavior indicates the rotational movement of the rotor.

  With reference to FIG. 6, in this example, first, the rotor of conveyance motor 27 is gradually rotated clockwise to be positioned at a predetermined position. Here, it is positioned at a predetermined position with three pulses. Next, the same process is performed on the reversing motor 28 while maintaining this state. Here, the conveyance motor 27 and the reversing motor 28 are connected by the belt 33, but the drive shaft of the conveyance motor 27 is connected to the belt 33 via the one-way clutch 35, so Even if the belt 33 is rotated in the reverse direction and the rotor of the reversing motor 28 is held, the rotor of the transport motor 27 does not move. As a result, it is possible to provide a stepping motor device that can easily deal with document jamming but can reliably hold DC excitation for a certain period of time, and can prevent step-out when the stepping motor is started.

  In addition, although the example which performs 3 times of short time excitation was demonstrated here, not only this but 1 time of excitation may be sufficient and it may be other than 3 times.

  Also, the rotation direction when inputting a pulse is not a fixed direction. In the reverse motor, the rotation direction is counterclockwise, clockwise, and counterclockwise. In the conveyance motor, the rotation direction is clockwise, counterclockwise, and clockwise. It is good.

  In the above-described embodiment, the stepping motor that rotates in the opposite direction provided in the document feeder is described as the paper transport device. However, the present invention is not limited to this, and the present invention is not limited to this. Regardless, the present invention may be applied to a plurality of stepping motors provided in the paper feeding device.

  In the above-described embodiment, the example in which the belt is used to rotate the driving unit of the conveyance roller and the driving shaft of the reversing motor has been described. However, the invention is not limited to this. Good.

  Moreover, in order to make it the structure which rotates only one of the two motors connected with the connecting member and does not rotate the other, the example using the one-way clutch has been described. Arbitrary arbitrary configurations may be adopted.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

1 is a block diagram illustrating a configuration of a digital multi-function peripheral including a document feeder having a stepping motor device according to an embodiment of the present invention. FIG. 3 is a diagram illustrating a main part of a document feeder. FIG. 4 is a diagram illustrating a state where a document is bitten in the document feeder. It is a figure which shows the state which connected the conveyance motor and the reverse motor. It is a figure which shows the state which connected the conveyance motor and the reverse motor. It is a timing chart which shows hold processing. It is a figure which shows the structure of the principal part of a stepping motor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Digital multifunction device, 11 Control part, 12 DRAM, 13 Operation part, 14 Document feeder, 15 Image reading part, 16 Image formation part, 17 Hard disk, 18 FAX communication part, 19 Network IF part, 25 Document tray, 26 Feed Paper motor, 27 transport motor, 28 reverse motor, 33 belt, 35 one-wet latch.

Claims (4)

A pair of stepping motors;
Connecting means for connecting the pair of stepping motors to rotate in the same direction;
In order to prevent step-out of the pair of stepping motors, the holding means for holding to match the positional relationship between the stator and the rotor constituting the stepping motor,
One of the pair of stepping motors is connected to the connecting means so as to rotate only in one direction when rotated by the connecting means ,
The holding means performs a hold for direct current excitation by rotating the rotor of one stepping motor in one direction for a certain period of time,
Thereafter, a stepping motor device that holds the other stepping motor rotated in the reverse direction and DC-excited for a certain period of time . The stepping motor device according to claim 1, wherein the holding unit maintains the hold of one stepping motor until the other stepping motor is held. Sheet conveying device using the stepping motor according to claim 1 or 2. An image forming apparatus comprising the sheet conveying device according to claim 3 .

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