JP4779672B2 - DC motor control apparatus and inkjet recording apparatus - Google Patents

Description

  The present invention relates to a DC motor control apparatus and an ink jet recording apparatus, and more particularly to a DC motor control apparatus and an ink jet recording apparatus that can quickly and accurately transport a recording medium to a target position.

  2. Description of the Related Art Conventionally, there is known an ink jet recording apparatus in which a transport apparatus that transports a recording medium is mounted, and an image is recorded on the recording medium by ejecting ink from a recording head onto the recording medium transported by the transport apparatus. In recent years, a DC motor (hereinafter referred to as a “DC motor”), which is cheaper than a pulse motor, is used as a drive source for a conveyance device mounted on the inkjet recording apparatus. In the inkjet recording apparatus, The conveyance of the recording medium is controlled by controlling the driving of the DC motor.

  As a method for controlling the conveyance of the recording medium, for example, an optical sensor capable of detecting the rotation amount of the DC motor is provided, and each time the DC motor rotates, the pulse signal output from the optical sensor is counted. A method for grasping the amount of rotation of the DC motor and controlling the conveyance of the recording medium is known.

  Further, regarding the method for controlling the conveyance of the recording medium as described above, a method as shown in FIG. 6 is known particularly when the recording medium is minutely conveyed. The upper part of FIG. 6A shows the position P of the recording medium at a predetermined time n, and the lower part of FIG. 6A shows the current value I output to the DC motor at the predetermined time n. It is.

When the recording medium is transported minutely, as shown in FIG. 6A, each time the recording medium is transported in the transport direction that is the direction toward the target position _Pref (the optical sensor is rotated by the rotation of the DC motor). Each time one pulse signal is output from the current), the process of outputting the current increasing from the current of the predetermined current value _{If at} a constant current increase amount _Af to the DC motor is repeated until the target position _{Pref is} recorded. The medium is transported.

However, in the example shown in FIG. _6A , the time T _rea is required until the recording medium reaches the target position P _ref , and the target arrival time T _ref is exceeded. Therefore, it can be considered that the current increase amount _Af of the current output to the DC motor is made larger than the value set in FIG.

FIG. 6B is a diagram corresponding to FIG. 6A, and shows a case where the current increase amount _Af of the current output to the DC motor is set larger than the value set in FIG. _6A . Yes. However, as shown in FIG. 6 (b), when the current increase amount _Af of the current output to the DC motor is set larger than the value set in FIG. 6 (a), recording is performed before the target arrival time _Tref. although it is possible to transport the medium to the target position P _ref, so-called overshoot recording medium is conveyed beyond the target position P _ref it was sometimes occur.

On the other hand, regarding the technique for conveying a recording medium minutely, the following Patent Document 1 discloses that the current increase amount _Af of the current output to the DC motor is set to be small in steps as the recording medium approaches the target position. A technique for quickly transporting a recording medium to a target position without causing overshoot is disclosed.
JP 2003-348878 A

  However, even with the technique disclosed in Patent Document 1 described above, it is still not possible to quickly convey the recording medium to the target position as compared with the case where the control is performed as described above with reference to FIG. There was a problem.

  SUMMARY An advantage of some aspects of the invention is to provide a DC motor control device and an ink jet recording apparatus capable of quickly and accurately transporting a recording medium to a target position. .

  In order to achieve this object, the DC motor control apparatus according to claim 1 is configured so that the recording medium is conveyed from a predetermined position to a target position based on a signal output from a detector that detects the rotation amount of the DC motor. A first control unit that controls driving of the DC motor and determines whether or not the recording medium has been transported in the transport direction from the predetermined position toward the target position based on a signal output from the detector; The determination unit and the first determination unit determine that the recording medium has been transported in the transport direction until the first determination unit determines that the recording medium has been transported in the transport direction again. In addition, a current output means for outputting to the DC motor a current that increases from a current of a predetermined current value by a first increase amount, and the recording medium based on a signal output from the detector. Second determination means for determining whether or not the medium has been conveyed to an intermediate position located between a predetermined position and the target position, and the second determination means determines that the recording medium has not been conveyed to the intermediate position. The first increase amount of the current output by the current output means between the predetermined position and the intermediate position is set to decrease as the recording medium approaches the target position. It is determined by the setting means and the second determination means that the recording medium has been conveyed to the intermediate position, and the first increase amount between the intermediate position and the target position is decreased by the first setting means. Is set to a value larger than the value of the constant increase last set by the first setting means from the intermediate position. And a second setting means for setting a second increment in until location.

  The DC motor control device according to claim 2 is the DC motor control device according to claim 1, wherein the second setting means sets the maximum value within a range in which the recording medium does not exceed the target position. Set as 2 increment.

  According to a third aspect of the present invention, in the direct current motor control apparatus according to the first or second aspect, the second setting means sets a constant value as the second increase amount.

  A DC motor control device according to a fourth aspect of the present invention is the DC motor control device according to any one of the first to third aspects, further comprising storage means for storing a position of the recording medium at each sampling time, and the first setting. The means calculates and sets the first increase amount based on a positional deviation between the position of the recording medium stored in the storage means and the target position.

  An ink jet recording apparatus according to claim 5 is a DC motor control apparatus according to any one of claims 1 to 4, a DC motor controlled by the DC motor control apparatus, and detection for detecting a rotation amount of the DC motor. And a recording apparatus that is driven by the DC motor and conveys the recording medium, and a recording head that ejects ink onto the recording medium conveyed by the conveying apparatus.

  According to the DC motor control apparatus of the first aspect, the current that increases by the first increase amount from the predetermined current value is output to the DC motor. As a result, when the recording medium is transported in the transport direction, the direct current is again A current that increases by a first increase amount from the predetermined current value is output to the electric motor, and the recording medium is transported again in the transport direction. Thus, the recording medium is conveyed from the predetermined position to the intermediate position. Here, since the first increase amount is set so as to gradually decrease as the recording medium approaches the intermediate position (target position), the recording medium is conveyed as the recording medium approaches the intermediate position (target position). Although it takes a long time to start the recording, the transport distance of the recording medium once becomes very small, and there is an effect that the recording medium can be accurately transported to the intermediate position.

  On the other hand, the second increase amount corresponding to the first increase amount during conveyance of the recording medium from the intermediate position to the target position is set by decreasing the first increase amount from the intermediate position to the target position. Assuming that it is set, a value larger than the value of the constant increase set at the end is set. Accordingly, the recording medium can be conveyed to the target position more quickly than when the first increase amount is continuously set between the intermediate position and the target position.

  That is, since the intermediate position is set in advance to a position that can be accurately conveyed to the target position by outputting a predetermined current, if the recording medium is accurately conveyed to the intermediate position, the recording medium as a whole Can be quickly and accurately conveyed to the target position.

  According to the DC motor control apparatus of the second aspect, in addition to the effect exhibited by the DC motor control apparatus of the first aspect, the second increase amount is a maximum value within a range where the recording medium does not exceed the target position. Therefore, the recording medium can be conveyed to the target position more quickly.

  According to the DC motor control device of the third aspect, in addition to the effect exhibited by the DC motor control device of the first or second aspect, the second increase amount is set as a constant value, so that the target value is set from the intermediate position. There is an effect that it is possible to reduce the processing load required for setting the current increase amount up to the position.

  According to the DC motor control device according to claim 4, in addition to the effect of the DC motor control device according to any one of claims 1 to 3, the first increase amount is a recording medium stored in the storage means. Therefore, the first increase amount can be calculated and set in a linear manner corresponding to the current position of the recording medium.

  According to the ink jet recording apparatus of the fifth aspect, since the DC motor control apparatus according to any one of the first to fourth aspects is provided, the same effect as the DC motor according to any one of the first to fourth aspects is provided. Can be played.

  An exemplary embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of the multifunction peripheral device 1 as viewed from the front, and FIG. 2 is a cross-sectional view of a printer structure mounted on the multifunction peripheral device 1. The multi-function peripheral device 1 has a printer function, a copy function, a scanner function, and a facsimile function. However, the present invention may be an inkjet printer device having a simple printer function.

  As shown in FIG. 1, the opening 2a on the front side (front side in FIG. 1) of the housing 2 in the multi-function peripheral device 1 is divided into upper and lower parts, and the lower side of the opening 2a is a recording medium ( An insertable paper feed cassette 3 for feeding the recording paper P) is arranged. The upper side of the opening 2a is a paper discharge unit 10 for discharging recorded recording paper P, and the recorded recording paper P is discharged in the direction of arrow A.

  The paper feed cassette 3 is a recording medium P as a recording medium (recording paper), for example, A4 size, letter size, postcard size, etc. A plurality of sheets can be stacked and stored along a direction orthogonal to (direction).

  An image reading device for reading a document in a copy function or a facsimile function is disposed on the housing 2. This image reading device is configured to be capable of opening and closing up and down with respect to one side end of the housing 2 via a pivot portion (not shown), and the rear end of the document cover 13 covering the upper surface of the image reading device is an image reading device. It is attached to the rear end so as to be rotatable up and down around the pivot axis. A document that is provided so that the document cover body 13 is opened on the upper side and a document is placed on the placement glass plate, and can be reciprocated in the main scanning direction (Y-axis direction) below the placement glass plate. A scanner for reading (for example, CIS: Contact Image Sensor) 70 (see FIG. 3) is configured to read an image on the original paper.

  On the upper side of the housing 2, an operation panel unit 14 provided with various operation buttons in front of the document cover 13 and a liquid crystal display device (hereinafter referred to as “LCD”) for displaying an operation procedure and a state of processing being executed. 15). An external memory insertion portion 11 for inserting an external memory is provided on the front surface of the housing 2 and below the operation panel portion 14. The external memory is, for example, CompactFlash (registered trademark), SmartMedia (registered trademark), Memory Stick (registered trademark), SD card (registered trademark), xD (registered trademark), or the like.

  As shown in FIG. 2, a printer unit 71 that performs recording on the recording paper P is provided in the multifunction peripheral device 1. Below the printer unit 71, on the back side (right side in FIG. 2) of the paper feed cassette 3, a bank unit 8 for separating paper is disposed. Further, an arm 6 a whose upper end is rotatable in the vertical direction is mounted on the front side of the housing 2 with respect to the bank portion 8 (upstream side in the conveyance direction (feeding direction) of the recording paper P). The paper feed roller 6 provided at the lower end of the arm 6 a is in contact with the uppermost one of the recording paper P stored in the paper feed cassette 3.

  When the paper feed roller 6 is driven in the paper feed direction (counterclockwise in FIG. 2), one sheet of recording paper P, which is a recording medium deposited on the paper feed cassette 3, is provided by the bank portion (inclined separation plate) 8. Separated and transported. The separated recording sheet P is fed to a registration roller pair 27 provided on the upper side (high position) behind the sheet feeding cassette 3 through an upward U-turn path (feeding path) 9.

  The printer unit 71 includes an ink jet recording head 4 that performs recording on the recording paper P, a carriage 5 that is mounted with the recording head 4 and can reciprocate in the main scanning direction, and a paper transport direction for reciprocating the carriage 5. A timing belt arranged in parallel to the upper surface of a guide member arranged on the downstream side (in the direction of arrow A), a CR (carriage) motor 25 that drives the timing belt and drives the carriage (DC motor in the embodiment) However, another motor such as a stepping motor may be used (see FIG. 3), a substantially flat plate-like platen 26 that supports the recording paper P conveyed on the lower surface side of the recording head 4, and the main scanning direction (Y And an encoder strip for detecting the position of the carriage 5 in the Y-axis direction (main scanning direction). To have.

  The strip-shaped encoder strip is arranged such that the inspection surface (the surface where slits are arranged at regular intervals in the Y-axis direction) is along the vertical direction. The predetermined position on the outer side of one end of the encoder strip in the Y-axis direction is the origin (home position) of the carriage 5, and it is detected whether or not the carriage 5 is set at the home position. A carriage home position sensor 73 is provided (see FIG. 3).

  Further, the printer unit 71 is provided with a registration roller pair 27 that conveys the recording paper P fed by the paper feed roller 6 to the lower surface of the recording head 4. The registration roller pair 27 rotates in the paper feeding direction (the upper roller rotates clockwise and the lower roller rotates counterclockwise), so that the recording head 4 provided downstream of the registration roller pair 27 in the transport direction. The recording paper P is conveyed onto the lower surface, that is, the platen 26. The registration roller pair 27 is a pair of upper and lower rollers. The upper roller is a driving roller that is driven by a conveyance motor 79 (see FIG. 3), and the lower roller is driven by the rotation of the upper roller. Driven roller.

  A paper sensor 72 that detects the recording paper P fed by the paper feed roller 6 is provided in the vicinity of the registration roller pair 27 and at an upper position upstream in the transport direction. The paper sensor 72 is configured by a general reflection type optical sensor including a light emitting diode and a phototransistor. If the recording paper P is not detected by the paper sensor 72 during the feeding period of the recording paper P by the paper feeding roller 6, the drive system such as the paper feeding roller 6 and the registration roller pair 27 is stopped and an error occurs. Is displayed.

  Further, on the downstream side of the platen 26, a spur roller 28a that is in contact with the upper surface of the recording paper P, and a paper discharge roller 28b that is provided on the lower surface side of the spur roller 28a and is driven by a conveyance motor 79 are arranged. The spur roller 28a is a driven roller that rotates following the paper discharge roller 28b, and both the rollers 28a and 28b are formed to be rotatable in forward and reverse rotation (paper feeding direction and anti-paper feeding direction). ing. In the present embodiment, the recording paper P is intermittently conveyed by intermittently driving the registration roller pair 27, the spur roller 28a, and the paper discharge roller 28b in the paper feeding direction.

  Although not shown, the printer unit 71 accommodates four colors of ink (black (BK), cyan (C), magenta (M), and yellow (Y)) for full-color recording. An ink cartridge, a plurality of ink supply pipes for supplying ink from each ink cartridge to the recording head 4, a flushing unit for periodically discharging ink (flushing) to prevent nozzle clogging during a recording operation, A maintenance unit is provided for cleaning the nozzle surface of the recording head 4 and performing a recovery process for removing bubbles in a buffer tank (not shown) on the recording head 4.

  Next, the electrical configuration of the multifunction peripheral device 1 will be described based on the block diagram of FIG. FIG. 3 is a block diagram showing an electrical configuration of the multifunction peripheral device 1. The multi-functional peripheral device 1 includes a CPU 61, ROM 62, RAM 63, EEPROM 64, image memory 65, clock circuit 66, network control unit (hereinafter referred to as “NCU”) 67, modem 68, CODEC 69, scanner 70, printer unit 71. , An interface (I / F) 81, an operation panel 14, and an LCD 15 are provided, and these are connected to each other via a bus line or the like. In addition, the multi-function peripheral device 1 is provided with various devices necessary for expressing each function of a printer function, a copy function, a scanner function, and a facsimile function, such as an audio LSI, a buffer, and an amplifier. .

  The NCU 67 is for line control, and the multifunction peripheral device 1 is connected to a telephone line (general public line) 90 via the NCU 67. The NCU 67 receives various signals such as a call signal sent from an exchange on a general public line and a signal indicating a telephone number (caller number) of a partner apparatus (caller), and operation of buttons on the operation panel 14. A dial signal at the time of transmission corresponding to the transmission is transmitted to the exchange, and further, an analog voice signal is transmitted / received during a call. The NCU 67 automatically receives a call from the telephone line 90 when receiving data, and automatically makes a call to the other party when sending data. Digital data representing the number of the other party is supplied from the CPU 61 to the NCU 67.

  The CPU 61, which is an arithmetic unit, controls each unit connected by a bus line or the like according to various signals transmitted / received via the NCU 67, executes data communication for facsimile operation and telephone operation, and transmits via the telephone line 90. The printed facsimile data (data including image information) and print data input from a personal computer or an external memory connected via the interface 81 (recording on the recording paper P) are executed.

  The CPU 61 executes control such as ejection of ink droplets, detection of the remaining amount of ink in the cartridge, and presence / absence of ink in accordance with a control program stored in advance in the ROM 62. Further, an ejection timing signal and a reset signal are generated, and each signal is transferred to a gate array (not shown). In addition, each device provided in the multi-function peripheral device 1 is connected to the CPU 61, and the operation of each device is controlled by the CPU 61.

  The ROM 62 is a non-rewritable memory storing a control program executed by the multi-function peripheral device 1 and fixed values. The ROM 62 has a program for executing the conveyance motor control process shown in FIG. A conveyance motor control program 62a is stored. The RAM 63 is a volatile memory for temporarily storing various data when the program stored in the ROM 62 is executed. The RAM 63 includes a recording medium position memory 63a. The recording medium position memory 63a is a memory that stores a conveyance position of the recording medium by counting pulse signals output from a rotary encoder 74 described later.

  The EEPROM 64 is a rewritable nonvolatile memory, and the data stored in the EEPROM 64 is retained even after the multifunction peripheral device 1 is turned off. The clock circuit 66 is for measuring time, and is updated by one (within a predetermined range), for example, at every falling edge of a clock having a predetermined frequency and a frequency dividing circuit and a pulse output from the frequency dividing circuit. And a counter. The time counted by the clock circuit 66 (count value of the counter) is read by the CPU 61 and used for each processing.

  The modem 68 is a post-modulation device, is connected to the NCU 67, converts analog data (such as data including encoded image information) transmitted via the telephone line 90 into digital data, and a multifunction peripheral device. Data to be output from 1 to the telephone line 90 (data including encoded image information) is converted from digital data to analog data. Therefore, it has a modulation and demodulation mechanism, and also has an audio reproduction mechanism that reproduces audio analog data that has been transmitted. Further, the modem 68 is for transmitting / receiving various procedure signals for transmission control, and is a transmission buffer used for temporarily storing the data when transmitting / receiving the data to / from the counterpart device. And a reception buffer.

  The CODEC 69 decodes the image information read by the scanner 70 and the encoded image information received via the telephone line 90. The decoded data (image information) is: Recording is performed on the recording paper P by the printer unit 71.

  The image memory 65 is a memory for storing a bit image (bit data) for recording, and is composed of a dynamic RAM (DRAM) that is an inexpensive large-capacity memory. Data (image information) decoded by the CODEC 65 is temporarily stored in the image memory 65, recorded on the recording paper P by the printer unit 71, and then erased from the image memory 65. The image information read by the scanner 70 is also stored in the image memory 65. The image information read by the scanner 70 is encoded by the CODEC 65 and output to the telephone line 90, and then erased from the image memory 65.

  The printer unit 71 is a device for performing recording (printing) on the recording paper P supplied into the multifunction peripheral device 1, and includes a paper sensor 72, a carriage home position sensor 73, a rotary encoder 74, the recording head 4, and recording. A head driver 75 that drives the head 4, a CR motor 25, a CR motor driver 76 that drives and controls the CR motor 25, a feed motor 77 that drives the paper feed roller 6, and a feed motor driver 78 that drives and controls the feed motor 77. And a conveyance motor driver 80 for driving and controlling the conveyance motor 79.

  The rotary encoder 74 is an optical sensor that can detect the rotation amount of the transport motor 79. In this embodiment, the rotary encoder 74 is provided so as to detect the rotation amount of the upper roller of the registration roller pair 27. That is, when the conveyance motor 79 is driven, the upper roller of the registration roller pair 27 rotates, and the rotation amount of the conveyance motor is increased by outputting a pulse signal each time the upper roller rotates by a predetermined amount. This is grasped and the conveyance of the recording medium is controlled.

  The head driver 75 is a drive circuit that applies a drive pulse having a waveform corresponding to a signal output from a gate array (not shown) to a drive element corresponding to each nozzle. The drive element is actuated by this drive pulse, and ink droplets are ejected from each nozzle.

  The CR motor driver 76, the feed motor driver 78, and the carry motor driver 80 are connected to the CR motor 25, the feed motor 77, and the carry motor 79, respectively, and a circuit that outputs a current to each of the connected motors 25, 77, and 79. It is.

  The interface 81 is a standard for electrical contacts, and is a device for connecting different devices. Via this interface 81, the multifunction peripheral device 1 is connected to a personal computer or a local area network (LAN) which is another device, and transmits / receives data to / from the personal computer or LAN (reception of print data). Execute. The received print data is converted into image information (bit image) and written in the image memory 65. The external memory insertion unit 11 is a connector and is connected to the CPU 61 via a bus line.

  Next, with reference to FIG. 4A, a control method when the recording medium of the present embodiment is minutely conveyed will be described. 4A shows the position P of the recording medium at a predetermined time n, and the lower part of FIG. 4A shows the current value I output to the transport motor 79 at the predetermined time n. FIG.

As shown in FIG. 4A, when the recording medium is transported slightly, first, a current having an initial current value I ₀ is output to the transport motor 79. The initial current value I ₀ is set to a value that makes it easier for the recording medium to start conveying against the static frictional force. Then, from the initial current value I ₀ , a current that increases by the initial current increase amount A _f0 is output to the transport motor 79 every sampling time.

As a result, when the recording medium is transported in the transport direction that is the direction toward the target position _Pref (when one pulse signal is output from the optical sensor by rotating the transport motor), the holding current value I _When the current of _f is output to the transport motor 79 and then the current that increases from the holding current value _If by the current increase amount A _f1 is output to the transport motor 79, the recording medium is transported to the intermediate position _Pch .

Here, the current increase amount A _{f (n)} between the conveyance start position and the intermediate position P _ch is set so as to decrease as the recording medium approaches the target position P _ref (A _f0 > A _f1 ). In the present embodiment, the current increase amount A _{f (n) at the} sampling time n is calculated and set by the formula A _{f (n)} = A _f0 / P _ref × {P _ref −P _(n) }.

That is, the current increase amount A _{f (n)} is obtained by setting a constant A _f0 / P _ref to the position deviation between the target position P _ref of the recording medium, P _ref −P _(n) , and the current position P _(n) of the recording medium. Calculated and set by multiplication. Therefore, the current increase amount A _{f (n)} can be calculated and set in correspondence with the current position of the recording medium.

As described above, by setting the current increase amount A _{f (n)} between the conveyance start position and the intermediate position _Pch among all the sections from the conveyance start position to the target position P _ref , the recording medium is set at the intermediate position P. As it approaches _ch (target position P _ref ), the time until the conveyance of the recording medium starts becomes longer, but the conveyance distance of the recording medium once becomes very small, and the recording medium is conveyed to the intermediate position P _ch with high accuracy. Can be made.

Thus, when the recording medium is conveyed to an intermediate position P _ch, a step of outputting a current which increases with current increase A _fs from the holding current value I _f to the conveying motor 79 every time the recording medium is transported in the transport direction Repeatedly, the recording medium is conveyed to the target position _Pref .

Here, as described above, the case where the current increase amount A _{f (n)} between the intermediate position _Pch and the target position P _ref is set to a constant value is compared with FIG. 4B. While explaining.

FIG. 4B is a diagram corresponding to FIG. 4A, and the upper part of FIG. 4B is a diagram showing the position P of the recording medium at a predetermined time n, as shown in FIG. The lower part is a diagram showing the current value I output to the transport motor 79 at the predetermined time n. Note that the current increase amount A _{f (n)} shown in FIG. 4B is similar to that described with reference to FIG. 4A, A _{f (n)} = A _f0 / P _ref × {P _ref −P _{( n)} }, the current increase amount A _{f (n) at the} sampling time n is calculated and set.

In the control method shown in FIG. 4B, even when the recording medium reaches the intermediate position _Pch , the current increase amount A _{f (n)} is continuously set so as to decrease as the recording medium approaches the target position P _ref. The control method is different from the control method shown in FIG.

4A and 4B, it is clear that the target arrival time T _ref can be satisfied by the control method of the present embodiment shown in FIG. 4A. On the other hand, with the conventional control method, the target arrival time T _ref cannot be satisfied.

As described above, according to the control method of the present embodiment shown in FIG. 4A, the arrival time to the target position P _ref can be shortened as compared with the control method shown in FIG. That is, the current increase amount A _fs shown in FIG. 4A is set to a value larger than the current increase amount A _f2 set after reaching the intermediate position _Pch shown in FIG. The recording medium can be conveyed to the target position _Pref more quickly than the control method shown in FIG.

In other words, from the transport start position to the intermediate position P _ch, it sets the current increase A _{f (n)} linearly in accordance with the conveyance status of the recording medium, the recording medium is precisely conveyed to middle position P _ch Is done. On the other hand, since the intermediate position _Pch is set in advance to a position where it can be accurately conveyed to the target position _Pref by outputting a predetermined current, as a result, the recording medium can be quickly moved to the target position _Pref . And it can convey correctly.

Further, since the current increase amount _Afs is set as a constant value, it is possible to reduce the processing load required for setting the current increase amount _{Af (n)} between the intermediate position _Pch and the target position _Pref . Furthermore, the current increase amount _Afs is preferably set to a maximum value within a range in which the recording medium does not exceed the target position _Pref . Thus, by setting the current increase amount _Afs , the recording medium can be transported more quickly to the target position _Pref .

  Next, a conveyance motor control process executed in the multifunction peripheral device 1 will be described with reference to the flowchart of FIG. This conveyance motor control process is a process for minutely conveying the recording medium.

In this transport motor control process, first, it is determined whether or not the position P _{n of the} recording medium has been transported beyond the intermediate position P _ch (S501). If it is determined that the position P _{n of the} recording medium does not exceed the intermediate position P _ch (S501: No), the current increase amount A _{f (n) is set} to A _f0 / P _ref × {P _ref −P _n }. (S502). On the other hand, if the position Pn of the recording medium is determined to exceed the intermediate position _{P ch} is (S501: Yes), set current increase _{A f (n)} to a constant value _{A fs} (S503).

Next, the current increase amount _{Af (n)} set in S502 and S503 is added to the current value I output previously, and the current value I output to the transport motor 79 is set (S504). Then, it is determined whether the maximum current value I _max is greater than or not the current value I set in S504 in order to prevent the the positive direction overcurrent is outputted is preset (S505), is smaller (S505 : No), the current of the current value I set in S504 is output to the transport motor 79. If the current value I is larger than the maximum current value I _max (S505: Yes), the current value I is reset to the holding current value _If , and the processing from S501 is repeated.

Next, as a result of outputting the current of the current value I, it is determined whether or not the position P _{n of the} recording medium matches the target position P _ref (S506), and if it matches (S506: Yes), Assuming that the recording medium has reached the target position P _ref , the current value I is set to the set holding current value _If (S509), and this process ends.

On the other hand, if the position _{P n} of the recording medium does not coincide with the target position _{P ref} (S506: No), whether the position _{P n} of the recording medium exceeds the position _{P n-1} of one sampling time before the recording medium not determine (S507), if exceeded (S507: Yes), set the current value I to the holding current value _{I f} (S508), and outputs a current of the set holding current value _{I f} to the conveying motor 79 . That is, this is a case where the position P _{n of the} recording medium is transported in the transport direction that is the direction toward the target position P _ref , and the transport motor 79 outputs a current having a holding current value _If .

On the other hand, if the position P _n of the recording medium does not exceed the position P _n−1 of the recording medium one sampling time ago (S507: No), the processing from S501 is repeated. That is, since the recording medium was not conveyed in the conveying direction (the pulse signal indicating that the recording medium was conveyed in the conveying direction was not output from the rotary encoder 74), the processing from S501 is repeated again.

As described above, according to the transport motor control process of the present embodiment, it is determined whether or not the recording medium exceeds the intermediate position _ch in the process of S501. If the recording medium does not exceed the intermediate position _ch (S501: No). , S502 is set so that the current increase amount A _{f (n)} decreases as the recording medium approaches the target position _Pref . On the other hand, if the intermediate position _ch is exceeded (S501: Yes), the current increase amount _{Af (n)} is set to a constant value of a predetermined magnitude by the processing of S503. Therefore, in the entire section from the conveyance start position to the target position, the recording medium is quickly and simply compared with the case where the current increase amount A _{f (n)} is set to decrease as the recording medium approaches the target position _Pref. It can be accurately transported to the target position.

  In the present embodiment, the first judging means described in claim 1 is the processing of S507 in the flowchart of FIG. 5, the current output means is the processing of S504 in the flowchart of FIG. 5, and the second judging means is the figure. 5 corresponds to the process of S601, the first setting means corresponds to the process of S502 of the flowchart of FIG. 5, and the second setting means corresponds to the process of S503 of the flowchart of FIG.

  As described above, the present invention has been described based on the embodiments, but the present invention is not limited to the above-described embodiments, and various improvements and modifications can be easily made without departing from the spirit of the present invention. It can be guessed.

For example, in the above embodiment, when the recording medium is conveyed, has been described of outputting the holding current value I _f is a constant value as a current value to be output first, such a holding current value I _f is constant It is not necessary to use a value, and a variable value may be used.

It is a perspective view of the multifunction peripheral device of this invention. It is sectional drawing of the printer part of the multifunction peripheral device of this invention. It is the block diagram which showed the electrical structure of the multifunction peripheral device. (A) The upper part shows the position P of the recording medium at a predetermined time n, and (a) the lower part shows the current value I output to the transport motor at the predetermined time n. (B) The upper part shows the position P of the recording medium at the conventional predetermined time n, and (b) the lower part shows the current value I output to the transport motor at the conventional predetermined time n. It is a flowchart of a conveyance motor control process. (A) and (b) are diagrams for explaining a conventional method for controlling conveyance of a recording medium.

Explanation of symbols

1 Multifunctional peripheral device (inkjet recording device)
4 Recording head 26 Platen (part of transport device)
27 Registration roller pair (part of conveyor)
28a spur roller (part of conveyor)
28b paper discharge roller (part of transport device)
61 CPU (part of control means)
74 Rotary encoder (detector)
79 Conveyor motor (DC motor)

Claims (5)

In the DC motor control device for controlling the driving of the DC motor so that the recording medium is conveyed from the predetermined position to the target position based on the signal output from the detector that detects the rotation amount of the DC motor,
First determination means for determining whether or not the recording medium has been transported in the transport direction from the predetermined position toward the target position based on a signal output from the detector;
Between the time when the first determination means determines that the recording medium has been transported in the transport direction and the time when the first determination means determines that the recording medium has been transported in the transport direction again, a predetermined current Current output means for outputting to the DC motor a current that increases with a first increase amount from a current of the value;
Second determination means for determining whether or not the recording medium has been transported to an intermediate position located between the predetermined position and the target position based on a signal output from the detector;
A first increase in current output by the current output means between the predetermined position and the intermediate position when the second determination means determines that the recording medium is not conveyed to the intermediate position. First setting means for setting the amount to decrease as the recording medium approaches the target position;
The second determination means determines that the recording medium has been transported to the intermediate position, and the first setting means continues to decrease and set the first increase amount from the intermediate position to the target position. Second setting for setting a value larger than the value of the constant increase last set by the first setting means as the second increase from the intermediate position to the target position. Means for controlling a DC motor.   2. The DC motor control apparatus according to claim 1, wherein the second setting unit sets a maximum value as the second increase amount within a range in which the recording medium does not exceed the target position.   The DC motor control device according to claim 1, wherein the second setting unit sets a constant value as the second increase amount. Comprising storage means for storing the position of the recording medium at each sampling time;
The first setting means calculates and sets the first increase amount based on a positional deviation between the position of the recording medium and the target position stored in the storage means. 4. The DC motor control device according to any one of items 1 to 3.   5. The DC motor control device according to claim 1, a DC motor controlled by the DC motor control device, a detector that detects a rotation amount of the DC motor, and the DC motor driven by the DC motor control device. An ink jet recording apparatus comprising: a transport apparatus that transports a recording medium; and a recording head that ejects ink onto the recording medium transported by the transport apparatus.

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