JP2009005576A - Stepping motor control device, image forming device, stepping motor and method of controlling stepping motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stepping motor control device reducing a load on a CPU and writing data smoothly without any delay. <P>SOLUTION: The stepping motor control device 26 is provided with: a buffer group 29 including a plurality of buffers for storing data for driving a stepping motor 24; an ASIC 27 for reading the data from the buffers; and a CPU 25 for writing the data into the buffers. The CPU 25 includes a first mode for writing the data in the buffers in a processing performed in a predetermined order, and a second mode for writing the data into the buffers upon receiving a request to write the data into the buffers from the ASIC 27. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a stepping motor control device, an image forming apparatus, a stepping motor, and a stepping motor control method, and more particularly to a stepping motor control device capable of reducing a load on a CPU and an image including such a stepping motor control device. The present invention relates to a forming apparatus, a stepping motor, and a stepping motor control method.

  In the image forming apparatus, a stepping motor is used as a paper feed motor for transporting paper in accordance with image formation. The rotation speed of the stepping motor is controlled by a stepping motor control device. Here, when the rotation speed of the stepping motor is changed suddenly, the stepping motor may step out. Therefore, the stepping motor control device is required to perform smooth start control and stop control of the stepping motor.

  A conventional stepping motor control device includes one buffer in an ASIC (Application Specific Integrated Circuit). A CPU (Central Processing Unit) writes pulse cycle data indicating a cycle for outputting a stepping motor driving pulse in a buffer. The ASIC reads the data written in the buffer and outputs a pulse based on the data. The pulse cycle data written to one buffer is for one step of rotating the stepping motor to a certain angle. For smooth start control and stop control of the stepping motor, data for a plurality of steps is required.

  At this time, if the writing of data for one step among the data for a plurality of steps is delayed, for example, the smooth start control and stop control of the stepping motor cannot be performed. Therefore, it is necessary to write data without delay.

  Here, techniques for writing data into a plurality of buffers are disclosed in Japanese Patent Application Laid-Open No. 8-149898 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2000-276435 (Patent Document 2).

  According to Patent Document 1, one of a plurality of buffers is a write target buffer, and the other is a read target buffer. Data is written while data is being read from the other read target buffer. Then, when the reading of data from the read target buffer is completed, the read target buffer and the write target buffer are switched.

According to Patent Document 2, data output from the processor is written in one of the plurality of buffers. Data output from the first buffer is written in the other second buffer. When data is written to the first buffer, the determination is made based on the ON / OFF state of the transmission interrupt signal, and the interrupt processing is performed.
JP-A-8-149889 (FIG. 1) JP 2000-276435 A

  According to Patent Document 1, data cannot be written unless all data is read from the read target buffer. In this case, since it is necessary to write data in a plurality of write target buffers all together, there is a possibility that the load on the CPU increases and the data writing is delayed.

  According to Patent Document 2, data writing is performed by interrupt processing. Therefore, when the number of data writing increases, the interrupt processing increases and the load on the CPU increases.

  An object of the present invention is to provide a stepping motor control device capable of reducing the load on the CPU and smoothly performing data writing without delay.

  Another object of the present invention is to provide an image forming apparatus capable of forming a good image.

  Still another object of the present invention is to provide a stepping motor having excellent control performance.

  Still another object of the present invention is to provide a control method for a stepping motor that can reduce the load on the CPU and can smoothly perform data writing without delay.

  The stepping motor control device according to the present invention includes a plurality of buffers that store data for driving the stepping motor, a reading unit that reads data from the buffer, and a writing unit that writes data to the buffer. The writing means performs a first mode for writing data to the buffer in a process performed according to a certain order, and a first mode for writing data to the buffer when a request for writing data is received from the reading means. 2 modes.

  Preferably, the writing means includes write buffer determination means for determining a buffer capable of writing data based on a write position register indicating a buffer to which data is written, among the plurality of buffers.

  More preferably, the reading unit includes a read buffer determining unit that determines a buffer from which data can be read based on a read position register indicating a buffer from which data is read out of the plurality of buffers.

  More preferably, the writing means writes data in a ring buffer format.

  In another aspect of the present invention, an image forming apparatus includes any of the stepping motor control devices described above.

  Preferably, the image forming apparatus includes an image forming unit that forms an image, a paper feed roller that transports paper to the image forming unit, and a stepping motor that rotates the paper feed roller. The stepping motor is controlled by a stepping motor control device.

  More preferably, the stepping motor control device controls the sheet feeding roller rotated by the stepping motor to slow up or slow down.

  More preferably, the image forming apparatus includes a transfer belt on which a visible image is formed by rotating, and a stepping motor that rotates the transfer belt. The stepping motor is controlled by a stepping motor control device.

  More preferably, the stepping motor control device performs control so as to keep the rotation speed of the transfer belt rotated by the stepping motor constant.

  In still another aspect of the present invention, a stepping motor includes any of the stepping motor control devices described above.

  In still another aspect of the present invention, the stepping motor control device controls the stepping motor by a CPU that performs a steady process and an interrupt process. The stepping motor control device includes a plurality of buffers. The stepping motor is driven based on data written in a plurality of buffers. The stepping motor control device writes data to a plurality of buffers in a steady process.

  In still another aspect of the present invention, a stepping motor control method controls a stepping motor by reading data written in a plurality of buffers by a reading unit. In addition, a step of writing data for driving the stepping motor into a plurality of buffers is provided, and the writing step includes a step of writing data to the buffer in a process performed in a certain order, and a writing of data from the reading unit Writing data to the buffer in response to the request.

  The stepping motor control device according to the present invention writes the data for driving the stepping motor in a process performed according to a certain order, and also receives a request to write data from the reading means and writes the data. As a result, it is possible to reduce the number of times the request is received and data is written. Then, the load on the CPU can be reduced, and data writing can be performed smoothly without delay.

  In addition, since the image forming apparatus according to the present invention includes the above-described stepping motor control device, it is possible to improve the control quality of the stepping motor and form a good image.

  In addition, since the stepping motor according to the present invention includes the above-described stepping motor control device, the load on the CPU can be reduced, and data writing can be performed smoothly without delay.

  In addition, the stepping motor control device according to the present invention writes the data for driving the stepping motor in the steady process. Thereby, since it is not necessary to write data by interrupt processing, the load on the CPU can be reduced, and data writing can be performed smoothly without delay.

  The stepping motor control method according to the present invention writes the data for driving the stepping motor in a process performed in a certain order, and writes the data in response to a data write request from the reading means. Do. As a result, the number of times data is written can be reduced according to the request. Then, the load on the CPU can be reduced, and data writing can be performed smoothly without delay.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a digital multifunction peripheral 10 when an image forming apparatus according to an embodiment of the present invention is applied to the digital multifunction peripheral 10. Referring to FIG. 1, the 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 the user in the digital multifunction peripheral 10, a document feeder 14 that automatically transports a document to a predetermined document reading position, and a document that has been transported by the document feeder 14 The image reading unit 15 that reads the image with a scanner at a predetermined reading position, the image forming unit 16 that forms the image from the document read by the image reading unit 15, and the sheet is automatically conveyed to the image forming unit 16. A paper transport unit 23 that stores data, a hard disk 17 that stores image data, and the like, a FAX communication unit 18 that is connected to the public line 20, and And a network IF (interface) unit 19 for connecting to a network 21.

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

  The digital multifunction machine 10 operates as a copying machine by forming an image in the image forming unit 16 via the DRAM 12 using the document 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.

Here, a specific configuration of the image forming unit 16 will be described. FIG. 2 is a schematic diagram illustrating a part of the image forming unit 16 provided in the digital multifunction peripheral 10. In FIG. 2, solid arrows indicate the flow of the paper 44, and dotted arrows indicate the rotation direction of the transfer belt 41. FIG. 3 is a schematic diagram showing an example of a yellow developing device 46a provided in the image forming unit 16 shown in FIG. 1 to 3, the image forming unit 16 includes a yellow developing unit 46a, a magenta developing unit 46b, a cyan developing unit 46c, and a black developing unit 46d. The yellow developing device 46a includes a photoreceptor 39a, a charging unit 35a, an exposure unit 36a, and a developing unit 37a. The charging unit 35a applies a voltage to the photoconductor 39a to charge the surface of the photoconductor 39a to a predetermined potential. The exposure unit 36a exposes a yellow light image formed on the surface of the photoreceptor 39a charged by the charging unit 35a based on the document read by the image reading unit 15. As a result, an electrostatic latent image is formed on the surface of the photoreceptor 39a. The developing unit 37a attaches yellow toner to the electrostatic latent image formed on the surface of the photoreceptor 39a to form a yellow toner image. Similarly to the developing device 46a, toner images of the respective colors are formed on the developing device 46b, the developing device 46c, and the developing device 46d. The formed toner images of respective colors are superposed in the order of yellow, magenta, cyan, and black on the transfer belt 41 rotating in the direction indicated by the dotted arrow in FIG. 2 so that color misregistration does not occur. Primary transcription. In this way, a visible full-color image composed of yellow, magenta, cyan, and black is formed on the transfer belt 41. The full color image formed on the transfer belt 41 is secondarily transferred to the paper 44 by the transfer roller 42. Specifically, the paper 44 is moved from the position indicated by P ₁ toward the image forming unit 16 in the direction indicated by the solid line arrow in FIG. 2 by the paper feed motor 45 provided in the paper transport unit 23. Be transported. When the paper 44 is conveyed to the position indicated by P ₂ and reaches the transfer roller 42, the full color image is secondarily transferred onto the paper 44 by the transfer roller 42. Thereafter, when the paper 44 is conveyed to the position indicated by P ₃ and reaches the fixing roller 43, the full-color image transferred onto the paper 44 is fixed by the fixing roller 43. In this way, a full color image is formed on the paper 44.

  The paper feed motor 45 is a stepping motor whose rotation speed is adjusted in accordance with the conveyance timing of the paper 44, and is controlled by a stepping motor control device. Here, a specific configuration of the stepping motor control device will be described. FIG. 4 is a block diagram showing the configuration of the stepping motor control device 26 and the motor drive unit 28. 1 to 4, the stepping motor control device 26 includes a CPU 25 and an ASIC 27. The ASIC 27 includes a buffer group 29 composed of a plurality of buffers. The motor drive unit 28 includes a stepping motor 24. The CPU 25 and the ASIC 27 are included in the control unit 11 shown in FIG. 1, but are separately shown in FIG. 4 from the viewpoint of facilitating understanding. In FIG. 4, a solid arrow indicates a data write signal, a dotted arrow indicates a data write request signal, and a thick arrow indicates a pulse output signal.

  The CPU 25 outputs a data write signal to the ASIC 27 and writes data to each buffer of the buffer group 29 provided in the ASIC 27. Here, the CPU 25 serves as a writing unit. The writing means writes data to the buffer when receiving a request to write data from the first mode for writing data to the buffer and a reading means to be described later in a process performed in a certain order. Second mode to be performed. Details will be described later.

  Data is pulse cycle data indicating a cycle for outputting a stepping motor driving pulse. Specifically, it includes the pulse width of the pulse to be output and the number of times the pulse having that pulse width is output. The data written in one buffer is one step for rotating the stepping motor 24 to a certain angle. For example, when the buffer group 29 is composed of eight buffers, one step is included in each of the eight buffers. A total of 8 steps are written. When the speed of the stepping motor 24 is changed, a plurality of data having different pulse widths are written in each buffer.

  The ASIC 27 reads data written in the buffer group 29 by the CPU 25. Here, the ASIC 27 serves as a reading unit. Based on the read data, a pulse is output to the motor drive unit 28. When the ASIC 27 has read all the data in the buffer group 29, the ASIC 27 outputs a data write request signal to the CPU 25 to request the CPU 25 to write the data. Upon receiving the request, the CPU 25 outputs a data write signal to the ASIC 27 and writes data to the buffer group 29.

  The motor drive unit 28 rotates the stepping motor 24 based on the pulse output from the ASIC 27. The stepping motor 24 rotates a paper feed roller (not shown) that contacts the paper 44 and conveys the paper 44.

  In this way, the stepping motor control device 26 controls the stepping motor 24. Specifically, when the stepping motor 24 is driven, so-called slow-up control in which the rotation speed of the stepping motor 24 is gradually increased and so-called slow-down control in which the rotation speed of the stepping motor 24 is gradually decreased may be performed. In such a case, a plurality of data having different pulse widths are required in a short time. Here, the CPU 25 writes a plurality of data having different pulse widths in each buffer. Then, the ASIC 27 reads data and outputs pulses having different pulse widths based on the data. The motor driving unit 28 finely changes the speed of the stepping motor 24 based on pulses having different pulse widths. In this way, the slow-up control and slow-down control of the stepping motor 24 are smoothly performed.

  FIG. 5 is a configuration diagram showing the configuration of the buffer group 29 provided in the ASIC 27. Referring to FIG. 5, the buffer group 29 is composed of eight buffers from a buffer 30a to a buffer 30h in this embodiment. Data for driving the stepping motor is stored in each of the buffers 30a to 30h, the data is written by the CPU 25, and the data is read by the ASIC 27. Data writing and data reading are performed in a ring buffer format.

  Specifically, for example, when data writing starts from the buffer 30a and ends up to the last buffer 30h, data writing starts again from the buffer 30a. Similarly, in the data reading, when the data reading is started from the buffer 30a and finished to the last buffer 30h, the data reading from the buffer 30a is started again.

  In the data writing, a buffer capable of writing data is determined based on a write position register 31 indicating a buffer in which data is written. Here, the CPU 25 serves as a write buffer determination unit. The write position register 31 moves to the next buffer when data writing is completed in the indicated buffer.

  Similarly, in reading data, a buffer from which data can be read is determined based on a read position register 32 indicating a buffer from which data is read. Here, the ASIC 27 serves as a read buffer determination unit. The reading position register 32 moves to the next buffer when reading of data in the indicated buffer is completed. In FIG. 5, the dotted arrow indicates the moving direction of the write position register 31, and the solid arrow indicates the moving direction of the read position register 32.

  As shown in FIG. 5, when the write position register 31 points to the buffer 30a and the read position register 32 points to the buffer 30e, the CPU 25 determines that the buffer 30d can be written from the buffer 30a. To do. That is, it is determined that the buffer 30a to the buffer 30d are buffers that have finished reading data and have not yet written data. Then, the ASIC 27 determines that the buffer 30h is a buffer that can be read from the buffer 30e. That is, the buffers 30e to 30h are determined to be buffers that have finished writing data and have not yet read data.

  In this way, by writing data and reading data, it is possible to write data and read data only by grasping the write position register 31 and the read position register 32. Therefore, data can be efficiently written and read by a simple method, and the load on the CPU 25 can be reduced.

  Further, by performing data writing and data reading in a ring buffer format, even if data writing or data reading is completed in the last buffer 30h, the data is immediately moved to the buffer 30a to be written or read Can be read subsequently. Therefore, the load on the CPU 25 can be further reduced.

  Here, processing of the CPU 25 when data is written to the buffer will be described. FIG. 6 is a flowchart showing the steady process of the CPU 25. With reference to FIGS. 1-6, the steady process of CPU25 is demonstrated first.

  The CPU 25 normally performs steady processing. Then, interrupt processing is accepted as necessary. The steady process includes a process of conveying a document by the document feeder 14, a process of reading an image of the document by the image reading unit 15, a process of forming an image from image data of the document by the image forming unit 16, A series of processes relating to image formation in the digital multi-function peripheral 10 including a process of conveying paper, and the like, is a process performed in a certain order.

  The CPU 25 performs a series of processes relating to image formation in a steady process (in FIG. 6, step S11, the following steps are omitted). Further, the CPU 25 performs a data write process for writing data to the buffer in a steady process (S12).

  Here, the data writing process will be described. FIG. 7 is a flowchart showing the data writing process. The data writing process will be described with reference to FIGS.

  The CPU 25 determines a buffer capable of writing data from the buffers 30a to 30h based on the write position register 31 (S21). In this embodiment, as shown in FIG. 5, the write position register 31 indicates the buffer 30a, and the read position register 32 indicates the buffer 30e. Therefore, as described above, the buffer 30a to the buffer 30d are determined as buffers capable of writing.

  Since there is a buffer in which writing can be performed (YES in S22), the CPU 25 writes data from the buffer 30a to the buffer 30d (S23). The data writing at this time corresponds to the first mode.

  If there is no buffer that can be written in step 22 (NO in S22), the data writing process is terminated and the steady process is continued.

  On the other hand, the ASIC 27 reads data written by the CPU 25. At this time, when all the data in the buffer group 29 has been read, the ASIC 27 outputs a data write request signal to the CPU 25 and requests the CPU 25 to write the data. That is, it requests the CPU 25 for interrupt processing.

  FIG. 8 is a flowchart showing interrupt processing. The interrupt process will be described with reference to FIGS.

  The CPU 25 receives a data write request signal from the ASIC 27 (S31). Then, as described above, since the ASIC 27 reads all data in the buffer group 29 as described above, the CPU 25 writes data from the buffer 30a to all buffers in the buffer 30h (S32). As described above, the interrupt process is a process of receiving a data write request from the ASIC 27 and writing the data. Then, as described above, this processing is requested to the CPU 25 at the timing when the ASIC 27 has read all the data in the buffer group 29. The interrupt processing is, for example, timing when a series of processing relating to image formation shown in Step 11 in FIG. 6 is completed, timing for determining a buffer capable of writing data, shown in Step 21 in FIG. , Requested at various times. Note that the data writing at this time corresponds to the second mode.

  As described above, the stepping motor control device 26 writes the data for driving the stepping motor by the steady process, and writes the data by the interrupt process. As a result, the number of times data is written by interrupt processing can be reduced. Then, the load on the CPU 25 can be reduced, and data writing can be performed smoothly without delay.

  Further, since the paper feed motor 45 is the stepping motor 24 controlled by the stepping motor control device 26 as described above, the CPU 25 is also used when a plurality of data is required in a short time such as slow-up control and slow-down control. Thus, data writing can be performed smoothly without delay. Then, the speed of the paper feed motor 45 can be changed more smoothly, and the paper can be conveyed appropriately.

  Further, since the digital multi-function peripheral 10 includes such a stepping motor control device 26, it is possible to improve the control quality of the stepping motor 24 and form a good image.

  In addition, such a control method of the stepping motor 24 writes data for driving the stepping motor by a steady process and writes data by an interrupt process. As a result, the number of times data is written by interrupt processing can be reduced. Then, the load on the CPU 25 can be reduced, and data writing can be performed smoothly without delay.

  In the above embodiment, the example in which the paper feeding motor 45 is the stepping motor 24 controlled by the stepping motor control device 26 has been described. However, the present invention is not limited to this, and the transfer shown in FIG. It can also be used for a driving roller 47 that contacts the belt 41 and rotates the transfer belt 41.

  Specifically, the stepping motor 24 rotates the drive roller 47. The driving roller 47 contacts the transfer belt 41 and rotates the transfer belt 41. The rotational speed of the transfer belt 41 is constantly monitored. For example, the rotational speed of the transfer belt 41 is constantly monitored by detecting the rotational speed of the transfer belt 41 in a predetermined section.

  As described above, a full color image is formed on the transfer belt 41 by superimposing the toner images of the respective colors. Therefore, when the rotational speed of the transfer belt 41 deviates from a predetermined rotational speed, color misregistration occurs. As a result, a clear full-color image cannot be formed, and the rotation speed of the transfer belt 41 needs to be kept constant.

  However, the rotation speed of the transfer belt 41 depends on slippage between the transfer belt 41 and the rollers that rotate the transfer belt 41, deterioration due to aging of the transfer belt 41, errors in manufacturing the transfer belt 41, and the like. Due to differences or the like, it may be difficult to keep constant. Therefore, in order to keep the rotation speed of the transfer belt 41 constant and prevent color misregistration, it is necessary to finely control the rotation speed of the roller that drives the transfer belt 41.

  In such a case, the stepping motor control device 26 corrects the rotational speed of the stepping motor 24 that rotates the driving roller 47. Specifically, the CPU 25 writes a plurality of data having different pulse widths in consideration of the characteristics of the transfer belt 41 described above in each buffer. Then, the ASIC 27 reads data and outputs pulses having different pulse widths based on the data. The motor drive unit 28 changes the speed of the stepping motor 24 based on pulses having different pulse widths. In this way, the rotational speed of the drive roller 47 is corrected, and the rotational speed of the transfer belt 41 is kept constant.

  By doing so, it is possible to perform a delicate correction of the rotational speed according to the transfer belt 41, and to keep the rotational speed of the transfer belt 41 constant. Thereby, it is possible to prevent color misregistration and form a clear full color image.

  In addition, any motor that uses the stepping motor 24, such as a registration motor, can be employed in other motors.

  In the above embodiment, the example in which data is written to a plurality of buffers from the buffer 30a to the buffer 30d in step 23 in FIG. 7 has been described. However, any one of the plurality of buffers is described. Data may be written to the buffer.

  In the above-described embodiment, an example in which data writing and data reading are performed in the ring buffer format has been described. However, the present invention is not limited to this, and another format may be used. For example, when the data writing is completed, the write position register 31 moves to a buffer other than the adjacent buffer. As a result, the CPU 25 writes data into another buffer. Similarly, the read position register 32 moves to a buffer other than the adjacent buffer. As a result, the ASIC 27 reads data from another buffer.

  In the above embodiment, the ASIC 27 has described an example in which an interrupt process is requested to write data to the CPU 25 when all the data in the buffer group 29 has been read. For example, an interrupt process may be requested to write data when data in a predetermined number of buffers is read by detecting that data in a predetermined number of buffers has been read.

  In the above embodiment, an example has been described in which data is written to all buffers when a data write request signal is received from the ASIC 27 in interrupt processing. However, the present invention is not limited to this, and data is written. What is necessary is just to discriminate | determine the buffer which can carry out and write data in two or more buffers.

  In the above embodiment, eight buffer groups 29 are provided from the buffer 30a to the buffer 30h. However, the number is not limited to eight, and may be two or more. FIG. 9 is a diagram illustrating an example of a buffer group 50 including two buffers. Referring to FIG. 9, the buffer group 50 includes a first buffer 51 and a second buffer 52.

  In the above embodiment, the example in which the CPU 25 and the ASIC 27 are included in the control unit 11 of the digital multi-function peripheral 10 has been described. However, the present invention is not limited to this, and a separate CPU and ASIC are provided inside the stepping motor control device. May be. In this case, the stepping motor control device can be employed in other devices that use a motor.

  Further, the stepping motor may include such a stepping motor control device 26. In this case, the stepping motor can reduce the load on the CPU and can smoothly perform data writing without delay.

  In the above embodiment, the example of performing data writing in the steady process and the interrupt process has been described. However, the present invention is not limited to this, and if only the steady process can be performed sufficiently, only the steady process is performed. Data may be written. By doing so, the stepping motor control device 26 writes the data for driving the stepping motor in a steady process. Thereby, since it is not necessary to write data by interrupt processing, the load on the CPU can be reduced, and data writing can be performed smoothly without delay.

  Further, in the above-described embodiment, the case where a full-color image is formed by the digital multifunction peripheral 10 has been described. However, the present invention is not limited to this, and the present invention is also applicable to the case where a monochrome image is formed.

  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 showing an overall configuration of a digital multifunction peripheral according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating a part of an image forming unit provided in the digital multifunction peripheral illustrated in FIG. 1. FIG. 3 is a schematic diagram illustrating an example of a developing device provided in the image forming unit illustrated in FIG. 2. It is a block diagram which shows the structure of a stepping motor control apparatus and a motor drive part. It is a block diagram which shows the structure of the buffer group with which ASIC is equipped. It is a flowchart which shows the steady process of CPU. It is a flowchart which shows a data writing process. It is a flowchart which shows an interruption process. It is a figure which shows an example of the buffer group comprised from two buffers.

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, 20 Public line, 21 Network , 22 PC, 23 Paper transport unit, 24 Stepping motor, 25 CPU, 26 Stepping motor control device, 27 ASIC, 28 Motor drive unit, 29, 50 Buffer group, 30a, 30b, 30c, 30d, 30e, 30f, 30g, 30h Buffer, 31 Write position register, 32 Read position register, 35a Charging unit, 36a Exposure unit, 37a Development unit, 39a Photoconductor, 41 Transfer belt, 42 Transfer roller, 43 Fixing roller, 44 Paper, 45 Paper feed motor, 46a 46b , 46c, 46d Developer, 47 Drive roller, 51 First buffer, 52 Second buffer.

Claims (12)

A plurality of buffers for storing data for driving the stepping motor;
Reading means for reading data from the buffer;
Writing means for writing data to the buffer;
The writing means receives a first mode for writing data to the buffer and a request to write data from the reading means in a process performed in a certain order, and stores data in the buffer. A stepping motor control device including a second mode for performing writing. 2. The write unit according to claim 1, wherein the write unit includes a write buffer determination unit that determines a buffer capable of writing data based on a write position register indicating a buffer to which data is written, among the plurality of buffers. Stepping motor control device. 3. The reading means according to claim 1, wherein the reading means includes reading buffer determination means for determining a buffer from which data can be read based on a reading position register indicating a data reading buffer among the plurality of buffers. The stepping motor control device described. The stepping motor control device according to claim 1, wherein the writing unit performs data writing in a ring buffer format. An image forming apparatus comprising the stepping motor control device according to claim 1. An image forming unit for forming an image;
A paper feed roller for transporting paper to the image forming unit;
A stepping motor for rotating the paper feed roller,
The image forming apparatus according to claim 5, wherein the stepping motor is controlled by the stepping motor control device. The image forming apparatus according to claim 6, wherein the stepping motor control device controls the paper feeding roller rotated by the stepping motor to slow up or slow down. A transfer belt on which a visible image is formed by rotating; and
A stepping motor for rotating the transfer belt,
The image forming apparatus according to claim 5, wherein the stepping motor is controlled by the stepping motor control device. The image forming apparatus according to claim 8, wherein the stepping motor control device controls the rotation speed of the transfer belt rotated by the stepping motor to be kept constant. A stepping motor comprising the stepping motor control device according to claim 1. A stepping motor control device that controls a stepping motor by a CPU that performs steady state processing and interruption processing,
Contains multiple buffers,
Based on the data written in the plurality of buffers, the stepping motor is driven,
A stepping motor control device that writes data to the plurality of buffers in the steady process. A stepping motor control method for controlling a stepping motor by reading data written in a plurality of buffers by a reading means,
A step of writing data for driving the stepping motor into a plurality of buffers;
The writing step includes a step of writing data to the buffer in a process performed in a certain order, and a step of writing data to the buffer in response to a data write request from the reading means. Control method.

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