JPS62173262A - Printing control of serial dot printer - Google Patents

Abstract

PURPOSE:To make the security of the same printing quality as that in a constant speed area even in the printing of rise-up time possible, by a method wherein in the first acceleration control area, the output pulse from an encoder is directly made to be a printing timing pulse and in the second acceleration control area, the corrected timing pulse obtained by adding a specific correction to the output pulse from the encoder is made to be the printing timing pulse. CONSTITUTION:In the acceleration area of a large speed difference among pulses while a printing head 1 is transferred from a stop state to a fixed speed state, two acceleration control areas of the first and the second acceleration control areas are provided and the control of printing is carried out. Then, in the acceleration area, an acceleration curve is determined. This acceleration curve is divided into the first acceleration control area A and the second acceleration control area B according to the amount of transfer (IPT number). As the control method for acceleration along the acceleration curve, a control flag, a setting duty, and the speed table having a desired speed are stored in ROM13 based on the acceleration curve. Then, by comparing the desired speed with an actual speed as to each IPT signal, a DC motor 5 is controlled by acceleration along the acceleration curve.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a printing control method for a serial dot printer, and particularly to a control method that enables printing in an acceleration region until the print head reaches a constant speed. .

[Conventional technology]

In serial printers that use a DC motor as the drive source for the print head, a slit disk is attached to the rotating shaft of the carriage motor in order to obtain speed and position signals. When passing between
Two-phase encoders that generate pulses are often used.

However, if an error occurs in the pulse interval, the dot pitch also changes periodically, resulting in an extremely poor print quality.

In order to deal with this problem, a control method using a Digimel filter (Japanese Patent Application No. 32550/1982) has been proposed. According to this control method, stable printing is made possible by eliminating periodic errors and outputting pulses at intervals of 1° greater than the correction value.

[Problem that the invention seeks to solve]

The above-mentioned control method using a digital filter is very effective in a constant speed region where there is relatively no speed difference between pulses, but when the print head transitions from a stopped state to a constant speed state, it is very effective in an acceleration range where there is a large speed difference between pulses. If the area is slow, the counter will overflow. As a result, a large error may occur in the calculation result by the digital filter.

Therefore, if printing is performed in all areas at the timing using the calculation results by the digital filter, there is a problem in that the printing quality at 9 o'clock in the rise is inferior to that in the constant speed area.

Therefore, the present invention has been made with attention to the above-mentioned problems, and its purpose is to provide print control for a serial dot printer that ensures the same print quality as in the constant speed area even when printing at 9 o'clock in the morning. The purpose is to provide a method.

[Means for solving problems]

The configuration of the present invention that achieves the above object includes a multi-phase encoder that detects the amount of rotation or movement of a DC motor that drives the print head in the scanning direction, and a multi-phase encoder that detects the amount of rotation or movement of the DC motor that drives the print head in the scanning direction. means for dividing the acceleration region up to the point in time into a first acceleration control region and a second acceleration control region according to the amount of movement of the DC motor, and performing acceleration control according to each region; The main feature is that the present invention is fully equipped with a printing control means that uses a direct printing timing pulse as a direct printing timing pulse, and in the second acceleration control region, uses a correction timing pulse obtained by adding a specific correction to an output pulse from an encoder as a printing timing pulse.

[Effect]

In order to print with high print quality in the acceleration region where the print head transitions from a stopped state to a constant speed state, the acceleration region is divided into a first acceleration control region and a second acceleration control region depending on the amount of movement of the DC motor. In the first acceleration control area, the output pulses from the encoder are directly used as printing timing pulses, and in the second acceleration control area, specific corrections are made to the output pulses from the encoder. The added correction timing pulse is used as a printing timing pulse, and printing is controlled using this pulse.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram showing an embodiment of a print control device for carrying out the print control method for a serial dot printer according to the present invention.

In the drawings, reference numeral 1 denotes a print head mounted on a carriage, which can be moved in the scanning direction by an endless belt 4 that is passed between a drive pulley 2 and a driven pulley 3.

A DC motor 5 drives the print head 1 and rotates in response to a mold motion signal from a motor drive circuit 6. This D
A two-phase encoder 7 is provided to detect the number of revolutions or the amount of movement of the C motor 5.

The two-phase encoder 7 includes a slit disk 8 attached to the shaft of the DC motor 5, and two sets of a light emitting element 9 and a light receiving element 10 facing each other with the slit disk 8 in between, with the slit disk 8 serving as the light emitting element. When passing between the light receiving element 9 and the light receiving element 10,
φ1 phase and φ2 phase with a constant phase difference for each constant rotation angle
It is designed to output phase pulse signals.

11 detects the edges of the output pulses φ1 and φ2 from the two-phase encoder 7, outputs a thin IPT signal, and outputs a thin IPT signal to the CPU 12.
This is an edge detection circuit that sends signals to

The CPU 12 calculates the rotation speed, movement amount, and print timing of the DC motor 5 based on the input IPT signal, and also inputs the rotation direction and voltage ON/OFF duty amount (hereinafter simply called duty) to the control signal to the motor drive circuit 6. (abbreviated as "amount"). Depending on the setting of the rotation direction, the DC motor 5 rotates in the specified direction.

The duty amount corresponds to the rotation speed of the DC motor 5, and when the duty amount is 0% (voltage value OV), the rotation speed is zero.
When the duty amount is 100% (maximum voltage value), the rotation speed is maximum.

13 is an RO that stores various data and reads it as necessary.
It is M.

Next, the operation of this device will be explained.

First, when a control signal is given from the CPU 12 to the motor and drive circuit 6, the DC motor 5 begins to rotate. When the DC motor 5 rotates, the belt 4 runs,
Print head 1 moves in the scanning direction.

As the DC motor 5 rotates, the two-phase machine/coder 7 outputs pulse signals of φ1 phase and φ2 phase having a constant phase difference for each constant rotation angle, as shown in the time chart of FIG. The signal is sent to the edge detection circuit 11.

The edge detection circuit 11 receives the output pulse φ1 from the two-phase motor/coder γ. The edge of φ2, that is, the rising edge and falling edge, is detected and a thin IPT signal is outputted and sent to the CPU 12.

Based on this IPT signal, the CPU 12 calculates the rotation speed, amount of movement, and print timing of the DC motor 5, and sends a print timing pulse to the print head 1.

In the acceleration region where the speed difference between pulses is large until the print head 1 shifts from a stopped state to a constant speed state, two acceleration control regions, a first acceleration control region and a second acceleration control region, are used as shown in FIG.
Two acceleration control areas are provided to perform printing control.

Specifically, in the acceleration region, an acceleration curve as shown in FIG. 3 is set.

This acceleration curve is divided into a first acceleration control area A and a second acceleration control area B depending on the amount of movement (IPT number). As shown in Figure 4, the division of acceleration regions A and B is determined by the control flag, which is the highest pit in the desired acceleration table.
” indicates the first acceleration control region, and “1” indicates the second acceleration control region Bi.

The first acceleration control area A is an area where gentle acceleration is performed in order to absorb as much mechanical play as possible and ensure the quality of accelerated printing, and the amount of movement is equal to the number of IPTs required to reach the constant speed area. The speed is set to 1/4 of the constant printing speed.

As a control method for accelerating along the acceleration curve, a speed table with control brush setting duty and desired speed as shown in Fig. 4 (A) and (B) is created based on the acceleration curve.
, 0M13, and by comparing the desired speed and actual speed for each IPT signal, the DC motor 5 is accelerated and controlled along the acceleration curve shown in FIG.

Details of the acceleration control of the DC motor 5 will be explained with reference to the flowchart in FIG.

First, as an initial setting, the duty D is set in the motor drive circuit 6.
Set 0%. In this embodiment, a duty of 30 is set.

Next, when a rotation direction is specified for the motor and drive circuit 6, the DC motor 5 begins to rotate slowly in the specified direction. When the rotation starts, the output pulse φ from the two-phase encoder 7
1. As mentioned above, φ2 is connected to C through the edge detection circuit 11.
The signal is input to the PU 12 as an IPT signal.

The CPU 12 uses this IPT signal and the previously input IP
A timer built into the CPU 12 reads the time between the T signal and the actual speed as a digital value.

When the IPT signal is not input for a certain period of time or more, the duty amount is reset to 100% to prevent the DC motor 5 from stopping.

When the actual speed of the DC motor 5 is read, the desired speed and control flag are read out from the ROM 13, and the next IP
The duty amount 1t calculated by calculation to maintain the DC motor 5 at the desired rotation speed until the T signal is generated is read out from the ROM 13.

When the control flag is “0”, the first acceleration control area A
It is determined that this is the case, and the duty amount read from the ROM 13 is directly sent without performing speed correction control. Further, as for the printing timing, as shown in FIG. 6, the output pulse φ1 of the encoder 7. Let the signal corresponding to the edge of φ2 be a timing pulse. The print head 1 is driven by this timing pulse.

When the control flag is "1", it is determined that the vehicle is in the second acceleration control region B, and speed correction control is performed.

That is, compare the actual speed with the desired speed, and if the actual speed is greater than the desired speed, set the duty O'% and set D.
The C motor 5 is rotated by inertia. When the actual speed is the same as the desired speed, or when it is less than the desired speed within 10 degrees, set the duty read as 0M13. When the actual speed is 10 degrees or more higher than the desired speed, the duty Dα% is set and the vehicle is accelerated. In this example,
Set the duty to 50% and accelerate.

When the duty setting is completed, the table pointers of the desired speed table and the duty table are updated.

As shown in FIG. 6, the print timing is determined by the CPU 12.
A specific correction is performed based on the actual speed data for each batch, and a correction timing that suppresses variations in the characteristics of the encoder 7 and fluctuations in acceleration is calculated, and is used as a print timing pulse.

The above operation is repeated for every 1 IPT signal.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the acceleration region of the print head can be adjusted in the first direction by the amount of movement of the DC motor.
It is divided into an acceleration control area and a second acceleration control area, and acceleration control is performed according to each area. In the first acceleration control area, the output pulse from the encoder is directly used as a printing timing pulse, and in the second acceleration control area, Since the print timing pulse is a correction timing pulse obtained by adding a specific correction to the output pulse from the encoder, it may be possible to print in the acceleration region without a run-up distance, but this printing may be possible in the constant speed region. All pages have print quality equivalent to that of

As a result, it is possible to eliminate the need for a run-up distance, simplify the printing mechanism, expand the printable area of the medium, and improve performance.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a printing control device implementing a printing control method for a serial dot printer according to embodiment 911 of the present invention, FIG. 2 is a time chart showing output signals, FIG. 3 is a graph showing an acceleration curve, and FIG. Figure 4 (A), (B
) is an explanatory diagram showing a table, FIG. 5 is a flowchart showing the operation of this device, and FIG. 6 is a time chart showing output signals. 1... Print head 5... DC motor 6... Motor drive circuit γ... Two-phase encoder 8... Slit disk 9... Light emitting element 10... Light receiving element 1
1... Edge detection circuit 12... CPU 13.
...ROM patent applicant Takashi Kanakura, Patent attorney representing Oki Electric Industry Co., Ltd. 1 Figure

Claims (1)

[Claims] 1. The number of rotations or amount of movement of the DC motor that drives the print head is detected by a multi-phase encoder, and the number of rotations, amount of movement, and printing of the DC motor are determined based on the detected output pulses. In a print control method for a serial dot printer that controls timing, the acceleration region where the print head moves from a stopped state to a constant speed state is divided into a first acceleration control region and a second acceleration control region depending on the amount of movement of the DC motor. In the first acceleration control region, the output pulses from the encoder are directly used as print timing pulses, and in the second acceleration control region, specific corrections are made to the output pulses from the encoder. A printing control method for a serial dot printer, characterized in that the added correction timing pulse is used as a printing timing pulse.