JPH0426395A - Pulse motor control system of sheet conveyer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a pulse motor control method for a sheet conveying device suitable for facsimile machines, copying machines, word processors, printers, etc., which convey sheet materials using a 1-2 phase excitation pulse motor. It is. [Prior Art] Conventionally, in a pulse motor control system of a sheet conveying device that conveys a sheet material using a pulse motor with 1-2 phase excitation, the current value when only one phase is excited 6n as shown in FIG. is larger than the current value for exciting both two phases, so that the rotation angle of the pulse motor when only one phase is excited is the same as the rotation angle of the pulse motor when both phases are excited. . [Problem to be Solved by the Invention] However, in the conventional example described above, since the damping characteristics of the motor itself during two-phase excitation are different from the characteristics during one-phase excitation, the rotation angle of the pulse motor during one-phase excitation is When trying to equalize the rotation angle of a pulse motor during two-phase excitation, 1
The ratio of the current value during two-phase excitation to the current during phase excitation becomes too small, and the output torque of the pulse motor itself decreases, resulting in step-out.The current value during one-phase excitation becomes too large. Failures such as exceeding the rating of the IC for motor driving force.

[There was one. Also, in order to control the current value with a microprocessor, there is a method of controlling the input terminal with a D/A converter, or a method of switching several types of series resistors, but both methods increase the hardware load. However, the drawback is that it is difficult to completely equalize the rotation angle of the pulse motor during one-phase excitation and the rotation angle of the pulse motor during two-phase excitation using a control method with a small degree of freedom. However, the rotation angle of the pulse motor during one-phase excitation and two-phase excitation was uneven as shown in FIG. As a result of the above, the amount of movement of the sheet material conveyed by the pulse motor becomes uneven, causing noise in the sheet material conveying device, and deterioration of image quality when the sheet conveying device constitutes a reader or printer. It had the disadvantage of being born alive. The purpose of the present invention is to solve the above-mentioned drawbacks.
The motor rotation during one-phase excitation is set by setting the time for passing current through the two phases relative to the time for passing current only through the one phase so that the step feed of the sheet material during phase excitation and during two-phase excitation is equal. This is intended to improve sheet conveyance accuracy and reduce noise by making the rotation angle of the motor during two-phase excitation equal. [Means for Solving the Problems] In order to achieve the above object, the present invention provides the following steps.
A sheet conveying device for step-feeding a sheet material using a phase-excited pulse motor, comprising a control means having a timer for determining the time period for which current is passed through two phases of the motor, and the control means is configured to The counting operation of the timer is started after the current starts flowing, and the counting time of the timer is 1.
The time for passing the current through the two phases is set as the time for passing the current through only the one phase so that the step feed of the sheet material during phase excitation and during two-phase excitation is equalized. [Embodiment] Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a block diagram of a pulse motor control circuit of a sheet conveying device, and 1o is a pulse motor excitation phase switching control section. This motor excitation phase switching control section 1o controls the setting of the pulse motor phase current value, the direction of the pulse motor phase current, etc. in synchronization with the pulse motor phase switching timing signal, and controls sending the pulse motor to the next phase. It has a microprocessor 11 and also has a timer 12 for producing timing signals to reduce the phase currents and an external output port 3. Furthermore, the RO stores the program and has tables shown in Figures 2 and 3.
It has M14. 20 is a pulse motor drive section. This pulse motor drive section 20 is
A pulse motor phase control signal that can set pulse motor drive currents of 0%, 20%, and 0%, is connected to the external output port 13 of the pulse motor phase switching control section 10, and is sent through the external output port 13. This is a driver that actually sends current to the pulse motor 30 according to a signal. Reference numeral 30 denotes a 1-2 phase excitation type pulse motor, which is connected to the pulse motor drive section 20 and receives power and power simultaneously. With this configuration, the rotation angles of the pulse motor during one-phase excitation and during two-phase excitation become equal, as shown in FIG. 4. Next, the operation of the above configuration will be explained with reference to the flowchart of FIG. When the microprocessor 11 of the pulse motor phase switching control section 10 receives the pulse motor phase switching timing signal, it starts a pulse motor phase switching routine shown in the flowchart of FIG. In this pulse motor phase switching routine, first, in step S1, the pulse motor phase current control timer 12 is initialized and started.
The timer 12 generates a timing signal for switching to the table 2 which reduces the phase current. In step S2, the next phase current data in the previous pulse motor phase current table is referred to, and then in step s3, the reference data is output to the external output photo 13 connected to the pulse motor drive section 20. Then, in step S4, it is determined whether or not the timer 12 has overflowed, and when it is detected that the timer 12 has reached a predetermined value, the timer 12 is stopped in step S5, and the phase current value table 1 is replaced with phase current value table 1 in step S6. Refer to Table 2 for phase current reduction. Next, in step S7, the reference data is output to the external output port 13 connected to the pulse motor drive section 2o. Then step S8
Add 1 to the table reference pointer. If the pulse motor phase switching timing (No. 8 is received again), the above-mentioned cycle will be repeated, and the motor excitation current and drive characteristics will be shown, which are not shown in Fig. 4. In this way, the phase current table and the phase As can be seen from the comparison of the current reduction tables, the phase reduction table height for two-phase operation is reduced from the phase current table for two-phase operation.In other words, the time for flowing strong excitation current through both phases of the two phases of the motor is The rotation angle of the motor during one-phase excitation and during two-phase excitation is made equal by setting the time to be shorter than the time during which strong excitation current is passed through only one phase.In addition, in the above embodiment, two-phase The strong excitation time of the excitation plane may be set short, or the current value may be changed at the same time. A sheet conveying device for step-feeding a sheet material using a pulse motor, comprising a control means having a timer for determining the time period during which current is applied to two phases of the motor, and the control means controls whether current is applied to the two phases of the motor. The counting operation of the timer is started after the current starts flowing, and the counting time of the timer is set to be equal to the step feed of the sheet material during 1-phase excitation and 2-phase excitation, relative to the time when the current flows only in the 1 phase. Since Mj is set as the time for flowing current to the two phases, the motor rotation angle for the first phase excitation is equal to the motor rotation angle for the two phase excitation, which can improve sheet conveyance accuracy. At the same time, it is possible to reduce noise.In addition, the degree of freedom in controlling the current value is increased, making it possible to achieve more detailed control, and since the motor excitation current is reduced in the latter half of the pulse motor phase switching timing, the pulse It has the effect of suppressing the damping characteristics of the motor.

[Brief explanation of the drawing]

FIG. 1 is a drive control block diagram of a pulse motor control method for a sheet conveying device according to an embodiment of the present invention, FIG. 2 is a diagram showing a phase current value table shown in FIG. 1, and FIG. 3 is a diagram showing a phase current value table shown in FIG.
4 is a diagram showing the relationship between the excitation current and drive characteristics of the motor shown in FIG. 1, and FIG. 5 is a flowchart of the control operation of the motor shown in FIG. FIG. 6 is a diagram showing the relationship between the excitation current and drive characteristics of a pulse motor of a conventional sheet conveying device. io...Pulse motor phase switching control unit, 11...Micro processor, 12...Timer, 13...Output boat, 14...ROM. 20... Pulse motor drive unit, 30... Pulse motor old power station 111-711.・Former Seshifu 7ba, ・IL Eats IL

Claims (2)

[Claims] (1) A sheet conveying device that feeds a sheet material step by step using a pulse motor with 1-2 phase excitation, comprising a control means having a timer that determines the time period for which current is passed through two phases of the motor; The means starts the counting operation of the timer after the current starts flowing through the two phases, and the counting time of the timer is set so that the step feeding of the sheet material during one phase excitation and during two phase excitation is equal to each other. 1. A pulse motor control system for a sheet conveying device, characterized in that the time for flowing current in the two phases is set as the time for flowing current only in the two phases. (2) The control means has a first table and a second table, and the second table is set to have a reduced current value compared to the first table, and is configured to control the counting operation of the timer. 2. The pulse motor control method for a sheet conveying device according to claim 1, wherein the second table is used in place of the first table upon termination.