JP2008012850A - Conveying device and recording apparatus provided with the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly detect a temperature rise of a motor even if a load fluctuates during driving of the motor.
The temperature rise of a motor is determined based on whether or not PWM exceeds a certain threshold value for a certain period of time while the paper feeding motor is being driven. By making this determination only during acceleration of the motor, erroneous determination due to an increase in the mechanical load is prevented.
[Selection] Figure 4

Description

  The present invention relates to a transport apparatus and a recording apparatus.

  In recent years, there are many conveyance devices and recording devices that employ a DC motor as a drive source, perform highly accurate position control by feeding back position detection information by an encoder, and employ servo control that can be driven at high speed. . In the control of the DC motor, unlike the control by the pulse motor, there is no step-out and high-speed rotation is possible.

  Further, the position information of the motor can be detected with high accuracy by using an encoder signal, and positioning control and speed control can be performed with high accuracy by feeding back the detection information.

  When the DC motor is continuously operated (conveying operation or recording operation), the temperature increases, the output torque decreases, and the control accuracy may eventually decrease. For this reason, processing such as detecting the temperature rise of the DC motor to lower the motor driving speed and providing a weight processing between driving is performed.

  As a means for detecting the temperature rise of the motor, a method is known in which a temperature sensor is provided in the motor or motor driver for detection.

Moreover, in patent document 1, it respond | corresponds to the temperature rise of a motor, without using a temperature sensor. The cumulative value of the output values of the control device during the motor driving period is calculated, and the stop time of the DC motor is determined based on the calculation result.
Japanese Patent Laid-Open No. 5-38179

  When detecting the temperature rise of the motor, for example, there is a method having a threshold value for each driving pattern of the motor. However, in a recording apparatus or the like, there are various recording operation modes, and the recording operation differs depending on the image data. Therefore, it is more complicated to detect the temperature rise.

  On the other hand, since the motor driving pattern of the paper feeding operation in the recording apparatus is limited to several patterns depending on the image quality to be recorded and the like, it is relatively easy to determine and control the threshold value.

  However, depending on the configuration of the paper feed mechanism, the mechanical load varies during the operation of the paper feed mechanism. For this reason, the power (PWM value) supplied to the DC motor also fluctuates due to load fluctuations. Since the magnitude of this load varies from device to device, it cannot be accurately determined with a uniform threshold.

  This invention is made | formed in view of the said subject, The objective is to provide the apparatus which judges the temperature rising of a DC motor appropriately.

  In order to solve the above-described problems and achieve the object, the transport apparatus of the present invention performs servo control of the DC motor using an encoder, and the first motor and the second roller aligned in the transport direction are moved by the DC motor. A conveying device that drives and conveys the sheet; a motor driver circuit that drives the DC motor; a PWM generation unit that performs the serve control and generates a PWM value output to the motor driver circuit; In the control means for providing a plurality of driving profiles of the DC motor, selecting one of the plurality of profiles to perform the paper feeding operation, and the acceleration control of the DC motor in the first roller, the PWM value is set for each servo cycle. Acquiring means, a counting means for counting based on a PWM value acquired by the acquiring means, and a threshold value of the PWM value, and the counting And based on the threshold value of the count value, determining means for raising the temperature of the DC motor, based on the determination result of the determination means, adjusts the spacing of the drive of the second roller.

  The recording apparatus of the present invention performs servo control of a DC motor using an encoder, and performs recording by scanning a recording head with respect to a sheet conveyed by a paper feed roller and a conveyance roller using the DC motor as a driving source. A recording device, a motor driver circuit that drives the DC motor, a PWM generation unit that performs the serve control and generates a PWM value output to the motor driver circuit, and a drive profile of the DC motor A plurality of control means for selecting one of a plurality of profiles and performing a paper feeding operation; and an acquisition means for obtaining the PWM value for each servo cycle in the acceleration control of the DC motor in the paper feeding roller. Counting means for counting based on the PWM value acquired by the acquisition means and a threshold value of the PWM value, and the count value and count Based on the threshold value, determining means for determining temperature increase of said DC motor, on the basis of the determination result of said determining means, for adjusting the interval between the scanning of the recording head.

  As described above, according to the present invention, it is possible to correctly detect the temperature rise of the motor even if there is a load fluctuation during driving of the motor.

  Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings.

[First Embodiment]
Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view illustrating a mechanism unit of a recording apparatus according to an embodiment.
Reference numeral 1 denotes an LF motor which is a drive source for transporting paper. Reference numeral 2 denotes an LF roller that conveys a sheet. Reference numeral 3 denotes an encoder for detecting the position and speed of the LF roller, which is mounted coaxially with the LF roller 2. The LF motor is a drive source for the paper feed roller and the transport roller.

  Reference numeral 4 denotes a paper feed roller for feeding paper to a tray (paper stacking unit). Reference numeral 5 denotes a pressure plate for pressing the stacked paper against the paper feed roller 4. Reference numeral 8 denotes a paper feed lever for connecting the driving of the LF roller 2 and the paper feed roller 4. When the carriage 7 (not shown in FIG. 1) for mounting the recording head moves and the paper feed lever 8 is pushed, the driving of the LF roller 2 is connected to the paper feed roller 4. When the paper feeding operation is performed, the pressure plate 5 is raised to press the paper against the paper feeding roller 4, and the paper feeding roller 4 and the separation roller (not shown) sandwich one paper. When this operation is performed, the mechanical load increases.

  When the separated paper is conveyed to the vicinity of the LF roller 1, the pressure plate 5 is lowered and the increased load of the paper feed roller 4 and the separation roller is reduced. As described above, the mechanical load accompanying the operation increases and decreases depending on the upper and lower sides of the pressure plate 5 and the separation roller.

  FIG. 2 is a control block diagram of the recording apparatus according to the embodiment. 9 is a CPU for controlling the recording apparatus and G.9. A. (Gate array) and 10 is a RAM. This RAM is provided with a recording buffer, a reception buffer, a work area for holding control parameters, and the like.

  Reference numeral 11 denotes a ROM which stores a CPU program and drive parameters. The drive parameters are a motor drive pattern, a print head drive table, and the like. Reference numeral 12 denotes a motor driver for driving the LF motor 1.

  The LF motor 1 is driven by servo control using position information and speed information obtained from the encoder 2. Servo control is implemented by the CPU 9 executing a program stored in the ROM 11. The servo control process is repeatedly performed every servo cycle ΔT.

  CPU and G.I. A. The PWM signal output from the (gate array) 9 to the motor driver 12 is represented by a duty value (ratio between high level and low level, ratio between on and off). The range of the duty value is 0% to 100%. The greater the duty value, the greater the power supplied to the motor.

  The sheet feeding roller 4 is transmitted with the driving force of the motor 1 by a transmission means provided between the sheet feeding roller 4 and the LF roller 2. Transmission (on / off) of the driving force between the LF roller 2 and the paper feed roller is switched by the paper feed lever 8.

  FIG. 7 is a perspective view of the recording apparatus. The recording head 704 mounted on the carriage 701 includes an ejection port (nozzle) that can eject ink and an ink tank that stores the ink. The ejection port of the recording head 704 is mounted on the carriage 101 with the ejection port facing downward so that ink is ejected onto the recording medium 705 positioned below.

  The carriage 101 is supported by two guide shafts 702 and 703 so as to be movable in the axial direction, and a scanning area including a recording area is set in the main scanning direction by driving a carriage motor (not shown). Reciprocal scanning is performed along the directions indicated by arrows Q1 and Q2. When one main scan by the carriage 701 is completed, the transport roller 706 transports the recording medium 705 by a certain amount (distance corresponding to the recording width by the recording head 704) in the sub-scanning direction that is the arrow P direction. In this manner, one page is recorded by repeating the scanning (operation) of the recording head and the conveyance (operation) of the recording medium. Reference numeral 707 denotes a platen.

  FIG. 3 is a flow of control of the recording operation in the embodiment. First, a sheet feeding operation is performed in S301. Next, in S302, it is determined whether or not the motor temperature increase flag is on. If the flag is off (N), the process proceeds to recording mode 1 in S303. If the flag is on (Y), the process proceeds to recording mode 2 in S304. In either case, a one-band recording operation (driving the CR motor) and a conveying operation (driving the LF motor) are performed.

  When it is determined that the temperature of the LF motor has increased during the paper feeding operation, control for preventing further temperature increase is performed in the subsequent transport operation (paper discharge operation).

  Recording mode 1 and recording mode 2 will be described with reference to FIG. 8A shows the recording mode 1, and FIG. 8B shows the recording mode 2.

  FIG. 8A is a diagram showing the scanning speed and scanning timing of the CR motor, the speed of the LF motor and the conveyance timing. As is apparent from the figure, in the period T1, acceleration control of the LF motor is performed at the timing of CR motor deceleration control. During this period T1, the two motors are driven simultaneously.

  FIG. 8B also performs the same driving as in FIG. However, the period T2 during which the motor is simultaneously driven is shorter than T1. Therefore, when the same image is recorded, the time during which the LF motor is driven is the same, but the time during which the LF motor is stopped in the recording mode 2 is longer than that in the recording mode 1. Therefore, when the motor temperature increase flag is on, the recording mode 2 is selected to prevent the temperature increase of the LF motor.

  Next, in S305, it is determined whether or not the recording for one page has been completed. If completed, the process proceeds to S306. If not completed, the process returns to S302.

In S306, a paper discharge operation is performed. However, here again, the flag may be determined, and if the flag is on, a process of performing a wait may be performed. Or you may perform the process which reduces a conveyance speed.
After performing the paper discharge operation in S306, it is determined in S307 whether or not to perform the recording operation for the next page.

  If the next page is to be recorded, the process returns to S301, and if the next page is not to be recorded, the process proceeds to S308 to shift to the standby state.

  In the standby state, it is determined whether there is an instruction to start recording from the host device while waiting. For example, if an instruction to start recording is not received for one minute, the recording head is capped and the flag is turned off.

  However, if an instruction to start recording is received within one minute, the motor temperature increase flag is not changed from on to off, and the motor temperature increase flag is kept on and the standby state is entered. Shift to the start of FIG.

  Supplementally, the reason why the process of turning off the motor temperature raising mode flag is not executed immediately after the printing operation for one page is that there is a possibility of receiving an instruction to start recording.

  If the paper feeding operation or the recording operation is performed before the temperature of the motor is completely lowered, the motor is heated again. In such a case, the recording mode is different for each motor temperature increase flag page (recording mode 1 or recording mode 2), and as a result, the image quality may be different for each page.

  As described above, the processing of FIG. 3 is summarized. When the motor is heated, recording is performed with the throughput of recording one page being reduced. Then, control is performed so that the recording sequence is not changed during a series of recording operations.

  FIG. 4 is a processing flow of the paper feeding operation in S301. In this, it is determined whether or not the temperature raising mode is turned on.

  First, in S401, a paper feeding operation is started, and servo control for driving the LF motor is started. At this time, the count value (Thot value) is initialized (the value is zero). This is the number of times that the PWM value exceeds the threshold during motor driving.

  Next, in S402, it is determined whether or not the LF motor is in acceleration control (acceleration control region). In the acceleration control, the rise of the pressure plate 5 and the separation roller has not started yet, and the PWM value is not affected by the increase of the mechanical load.

  If S402 is true (Y), the process proceeds to S403. In S403, it is determined whether or not PWM value> threshold (PWM hot, for example, 90%). The rise of the PWM value is determined by this PWM hot.

  PWMhot can set an individual value for each motor drive pattern. In the present embodiment, there are three print modes (motor drive modes): a speed priority mode, a standard mode, and an image quality priority mode. A speed profile corresponding to this drive mode is provided. This speed profile has different speed information so that each can perform appropriate acceleration. A threshold value can be provided corresponding to this drive mode.

If S403 is true (Y), the process proceeds to S404. If S403 is false (N), the process returns to S402.
Next, in S404, the value of Hot is added (incremented). Update the count value.

  Next, in S405, it is determined whether or not Hot> Thotlimit. Thotlimit is a threshold value (for example, 15) for evaluating the number of times the PWM value has been exceeded. It can be seen that the greater the number of times, the longer the PWM value exceeds the threshold. Therefore, when the count value exceeds the threshold value, it can be considered that the temperature of the motor is rising. On the contrary, while the count value is small, it can be considered that the time when the PWM value exceeds the threshold is short and the temperature of the motor has not risen. In addition to the counting method, a method of measuring the length (time) of the period exceeding the threshold may be used.

  In the present embodiment, it is possible to correspond to each print mode as in PWM hot. Alternatively, as another embodiment, the same value may be used regardless of the print mode.

  If S405 is true (Y), the process proceeds to S406. In S406, the motor temperature raising flag is turned on. If S405 is false (N), the process returns to S402.

  Next, constant speed control is performed in S407. In S408, deceleration control is performed. In S409, positioning control is performed, and the paper feeding operation is terminated.

  The processes from S402 to S405 are performed once for each servo cycle ΔT. This servo cycle is 1 millisecond, for example. Therefore, if the above-described count value is 20, it can be considered that there is a period in which the PWM value is greater than the threshold value for 20 milliseconds. In this case, since the count value is 20, which is larger than the threshold value of 15, the motor temperature increase flag is set.

  4 is summarized, the temperature rise of the motor is determined by determining whether or not the PWM value exceeds a threshold value for a certain period during the driving of the motor in the paper feeding operation. By performing this determination only for motor acceleration control, erroneous determination due to an increase in mechanical load is prevented.

  With the above configuration, conventionally, as shown in FIG. 5, the temperature rise of the motor was erroneously detected due to the load fluctuation of the mechanism during the paper feeding operation, but as shown in FIG. By monitoring the PWM value at an appropriate timing, it is possible to prevent erroneous determination of the temperature rise of the motor.

<Other embodiments>
Although the embodiment has been described above, the switching (ON / OFF) of the driving force between the LF roller 2 and the paper feed roller shown in FIG. It may be done.

  Further, for example, in the control flow of FIG. 4, the length of the period for monitoring the PWM value for determining whether or not the PWM value exceeds the threshold value may be varied for each motor drive mode. That is, the length of the period from the start of monitoring the PWM value to the end of monitoring the PWM value is made different for each drive mode.

  Alternatively, even if the length of the period from the start of monitoring the PWM value to the end of monitoring the PWM value is the same, the start timing for monitoring the PWM value may be different for each motor drive mode.

  Further, the combination of the length of the period from the start of monitoring the PWM value to the end of the monitoring of the PWM value and the start timing of monitoring the PWM value may be varied for each motor drive mode.

  This is because the motor control profile (speed profile or position profile in servo control) differs depending on the motor drive mode, and the period and timing when the PWM value increases.

  The threshold value of the PWM value is not limited to 90%, but may be another value (85% or 95%).

The perspective view which shows the mechanism part of the recording device in embodiment Control block diagram for controlling the recording apparatus in the embodiment Processing flow of motor temperature rise control of recording apparatus in embodiment Processing flow of sheet feeding operation of recording apparatus in embodiment Operation explanatory diagram of the conventional example Operation explanatory diagram of the embodiment The perspective view of the recording device of an embodiment Explanatory drawing of recording modes 1 and 2 of the embodiment

Claims (5)

A conveying device that conveys a sheet by performing servo control of a DC motor using an encoder and driving the first roller and the second roller arranged in the conveying direction by the DC motor,
A motor driver circuit for driving the DC motor;
A PWM generation unit that performs the serve control and generates a PWM value output to the motor driver circuit;
A plurality of DC motor drive profiles;
In the acceleration control of the DC motor in the first roller, acquisition means for acquiring the PWM value for each servo cycle;
Counting means for counting based on the PWM value acquired by the acquisition means and a threshold value of the PWM value;
Determination means for determining a temperature rise of the DC motor based on the count value and a threshold value of the count value;
A conveyance device that adjusts an interval of driving of the second roller based on a determination result of the determination unit.   The transport apparatus according to claim 1, wherein a threshold value of the PWM value is different for each drive profile.   The transport apparatus according to claim 1, wherein the acquisition unit varies a period for acquiring the PWM value for each drive profile.   The transport apparatus according to claim 1, wherein the acquisition unit varies a timing at which acquisition of the PWM value is started for each of the drive profiles. A recording apparatus that performs servo control of a DC motor using an encoder and performs recording by scanning a recording head with respect to a sheet conveyed by a paper feed roller and a conveyance roller using the DC motor as a drive source,
A motor driver circuit for driving the DC motor;
A PWM generation unit that performs the serve control and generates a PWM value output to the motor driver circuit;
Control means comprising a plurality of drive profiles of the DC motor, selecting one of the plurality of profiles and performing a paper feeding operation;
In the acceleration control of the DC motor in the paper feed roller, an acquisition unit that acquires the PWM value for each servo cycle;
Counting means for counting based on the PWM value acquired by the acquisition means and a threshold value of the PWM value;
Determination means for determining a temperature rise of the DC motor based on the count value and a threshold value of the count value;
A recording apparatus, wherein a scanning interval of the recording head is adjusted based on a determination result of the determination unit.

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