JP2742243B2 - Print correction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing correction method, and more particularly to a printing correction method for a serial printer having a bidirectional printing function.

[0002]

2. Description of the Related Art Conventionally, in a serial printer having a bidirectional printing function, an open loop control type stepping motor is used as a driving source for space driving.
In the case of a stepping motor, when the motor is rotating at a constant speed, the distance between the step command and the actual rotation angle
There is always an almost constant delay angle. This delay angle is determined by the relationship between the torque of the stepping motor and the load during steady rotation. In addition, transmission members such as timing belts and gears that transmit the driving force of the stepping motor to the carrier have elastic deformations such as rattling, backlash, and elongation. , The amount of elastic deformation changes. As a result, a delay occurs between the step command and the position of the carrier on which the print head is mounted. This delay varies between each device, changes in the device temperature, aging, and the like. This delay has caused printing misalignment when bidirectional printing is performed.

Therefore, in the case of ruled line printing or composite printing,
In order to unavoidably print in one direction or to reduce the amount of delay even slightly, make adjustments between each device, install a temperature sensor, and set a fixed correction value corresponding to each temperature to a step command and a print command. (For example,
JP-A-58-8666).

Alternatively, a position sensor such as an encoder corresponding to a print dot is installed in parallel with the operation direction of the carrier, and dots are printed in synchronization with a signal from the position sensor.

[0005]

In this conventional bidirectional printing type serial printer, if a position sensor is installed in parallel with the operating direction of the carrier and controlled by a closed loop control method, the right and left directions can be controlled. Although the dot position does not shift during printing, there is a problem that the control becomes complicated and the cost increases accordingly.
Therefore, it has been unavoidable to print a composite character such as a ruled line in one-way printing. This is a drawback that causes a decrease in throughput in the printer device.

Further, it is necessary to adjust the variation in the amount of delay between the step command and the carrier position due to the difference in the amount of backlash and backlash from one printer to another due to variations in the shape of the transmission member. The workability was reduced.

Further, the delay angle, the amount of backlash, the amount of backlash, and the amount of elastic deformation of the stepping motor are also affected by fluctuations in the temperature of the apparatus and aging of the apparatus, and sliding due to friction between the carrier bearing and the guide shaft. When the resistance changes, the delay angle changes correspondingly, and the amount of backlash and backlash changes due to the shape deformation of the transmission member due to thermal expansion, thermal shrinkage, friction, etc., and the characteristics of the transmission member change. The change changes the amount of elastic deformation. Therefore, the amount of delay between the step command and the carrier position also changes, and a dot position shift occurs particularly in rightward and leftward printing, resulting in a disadvantage that print quality is degraded.

In Japanese Patent Application Laid-Open No. 58-8666,
The print correction is performed by giving a fixed delay time between the step command and the print command with reference to the various delay elements described above. However, the carrier position is different between the rightward print and the leftward print. However, there is a drawback that the printing correction cannot be said to be perfect because the element of the movement error occurring in the above is not taken into account.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, an object of the present invention is to detect a movement error of a carrier in a left direction and a right direction in advance using a temperature as a parameter, respectively, and to perform a print correction based on the temperature. It is to provide a method.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a print correction method for a serial dot printer, which is controlled by a microprocessor and performs printing while moving a carrier on which a print head is mounted in a horizontal direction by a stepping motor. A carrier position detection sensor provided at one end of the carrier for detecting a movement error in the right and left directions when the carrier moves in the right and left directions, and an output switching position of the carrier position detection sensor provided in the carrier. A sensor error caused by detecting a sensor detection movement error in the rightward and leftward movements of the carrier by the passing member and the carrier position detection sensor, and subtracting the actual movement error of the carrier from the sensor detection movement error. Determining means according to the apparatus temperature, and the apparatus temperature Based on the constant sensor error according to the above and the sensor detection movement error detected by the carrier position detection sensor, the printing timing is corrected in advance in one of right and left directions or both directions by storing in advance. Correction means, and a start timing generating means for generating a start timing for the correction means,
According to one of the change of the apparatus temperature and the elapse of the set time, or the combination of both, the print correction time by the correction means is updated by the start timing generated each time.

Further, in the printing correction method according to the present invention, the carrier position detecting sensor is a transmission type photo sensor, and the member passing through the output switching position is a shielding plate formed of a part of the shape of the carrier. Alternatively, the carrier position detection sensor may be a reflection type photo sensor, and the member passing through the output switching position may be a reflection plate attached to the carrier.

Still further, in the print correction method according to the present invention, the determining means for determining the constant sensor error according to the apparatus temperature automatically adjusts the sensitivities of the A / D conversion circuit, the temperature sensor, and the carrier position detection sensor. A position sensor sensitivity measurement circuit for measuring the position of the carrier position detection sensor, wherein the position sensor sensitivity measurement circuit switches on and off a light emitting element circuit of the carrier position detection sensor by a trigger of the microprocessor; A timer started by a trigger of the microprocessor and stopped when the voltage level of the light receiving element circuit of the carrier position detection sensor reaches a certain level,
Further, the start timing generating means may include an A / D conversion circuit, a temperature sensor, and a timer which is stopped by a trigger of the microprocessor and stops after a given time elapses.

[0013]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram of one embodiment of the present invention. This embodiment is configured as follows.

A temperature sensor 1 for measuring an apparatus temperature of the printer is installed inside the apparatus, and a voltage value of the temperature sensor 1 is converted into a digital signal by an A / D conversion circuit 15 and transmitted to the microprocessor 10. I do. At the left end of the device, a transmission type photosensor 3 as a sensor for detecting a carrier position is provided, and a light emitting element circuit side of the photosensor 3 is provided with a switch 12 which is turned on / off by a command from the microprocessor 10. Have been. The carrier 4 on which the dot impact print head 2 is mounted is slidably held by guide shafts 5 and 6, and is commanded by the microprocessor 10 by a gear system 7 as a transmission member and a timing belt 8 carrying the carrier 4. The driving force of the stepping motor 9 driven by the
Perform reciprocating motion in the left and right direction.

The carrier 4 is provided with a shielding plate 4a composed of a part of the carrier shape. The carrier 4 moves to the left end of the apparatus, thereby blocking the output switching position of the photo sensor 3 for detecting the carrier position. The structure is such that when the shielding plate 4a is blocking the photo sensor 3, the photo sensor 3 is off, and when not blocking, the photo sensor 3 is on. The dot impact print head 2 has a plurality of dot heads in the vertical direction, and performs printing by driving the print driver 11 while moving in the horizontal direction. The sensor timer 13 is a timer that is started by a trigger of the microprocessor 10 and is stopped when the photosensor 3 is turned on from off or from on to off by the movement of the carrier 4, and the switch 12 is triggered by the trigger of the microprocessor 10. It is also a timer that starts at the same time as turning on or off and stops when the photosensor 3 turns from off to on or from on to off. The microprocessor 10 can read the timer value. The activation timer 14 is a timer whose time can be set arbitrarily by the microprocessor 10, started by a trigger of the microprocessor 10, and stopped when the set time has elapsed.

When the carrier 4 moves, a movement error occurs between the step command and the carrier position due to the delay angle of the stepping motor 9 and the backlash, backlash, extension, etc. of the gear system 7 and the timing belt 8. ing. This movement error is detected by the photo sensor 3. here,
The sensor detection movement error of the carrier 4 detected by the photo sensor 3 includes a sensor error,
The actual movement error of the carrier 4 is obtained by subtracting the sensor error, and the printing correction is performed based on the obtained error. This series of operations will be described with reference to FIGS. 2 to 4 and Table 1.

FIG. 2 shows a time until the light emitting element of the photosensor 3 is turned on by light emission, a time until the light is turned off by light extinction, a time until the light is emitted from the shielding plate 4a, and a time until the light is turned off by entering the shielding plate 4a. FIG. 7 is an example of a sensor error characteristic diagram showing a relationship with time.

Normally, when the output of the photosensor 3 is switched, there is a sensor error due to hysteresis. As shown in FIG. 2, the sensor error has a different value depending on the light emission or extinction of the light emitting element and the escape or entry of the shielding plate 4a. This is mainly because the amount of light entering the light receiving element is different between the amount of light emitted by the light emitting element when the switch 12 is turned on and the amount of light emitted from the shielding plate 4a when the switch 12 is fully lit, and the switch 12 is turned off. This is because the amount of afterglow remaining when the light emitting element is extinguished at the time is different from the amount of light due to shielding when entering the shielding plate 4a. And
The characteristics of this sensor error also vary with changes in the device temperature.

Table 1 shows the difference between the sensor error when the output of the photosensor 3 is switched by the shielding plate 4a and the sensor error when the light emitting element circuit of the photosensor 3 is turned on and off by the switch 12 in order to determine the sensor error. 5 is an example of a table for providing a correction value for correcting the error.

[0021]

[Table 1]

When the printer is designed, the temperature of the device, the sensor error when the output of the photosensor 3 is switched by the shielding plate 4a, and the sensor when the light emitting element circuit of the photosensor 3 is turned on and off by the switch 12 are designed when the printer is designed. The relationship with the error is grasped by an experiment or the like, created and stored in the memory.

FIG. 3 is an explanatory diagram of sensor error detection of the photo sensor 3. FIGS. 4A to 4D are explanatory diagrams showing how the carrier delay time is detected when the carrier 4 moves.

Referring to FIGS. 3 and 4 (a) to 4 (d),
The operation of this embodiment immediately before printing in an initial state after the power of the printer is turned on will be described.

In determining the sensor error, first, the sensor error when the light emitting element circuit of the photosensor 3 is turned on and off by the switch 12 is measured. At this time, the carrier 4 is stopped in advance at a position moved Lx steps to the right from the position where the output of the photosensor 3 switches from off to on (FIG. 4A), and the photosensor 3 is turned on. I have. Here, Lx is the number of steps sufficient for the speed vibration of the carrier 4 to converge to a speed variation width that does not affect the printing quality when the carrier 4 is moved at the printing speed S. Then, as shown in FIG. 3, the switch 12 is turned off by the trigger of the microprocessor 10, and at the same time, the sensor timer 13 is started.
Measure a. Next, the switch 12 is turned on by the trigger of the microprocessor 10, and at the same time, the sensor timer 13 is started, and the sensor on error m2a is measured during the time when the photo sensor 3 is turned on from off. Then, the microprocessor 10 takes in the data from the temperature sensor 1, applies the temperature data, the sensor-off error m1a and the sensor-on error m2a to the table shown in Table 1, and determines the sensor-off error m1 and the sensor-on error m2. I do.

Next, the carrier 4 is moved leftward at the printing speed S. At this time, the microprocessor 10 monitors the photo sensor 3 one by one, and stops feeding the carrier 4 by Lx + n steps from the position where the output of the photo sensor 3 is switched from on to off by the entry of the shielding plate 4a (FIG. 4).
(B)). Here, n is the number of margin steps in consideration of the sensor error, and is a value larger than the number of steps of the sensor error. If 4 carriers 4 in (b) is a point PL ₁ was stopped position, the sensor-off error m1 of the point PL ₁ photosensor 3, the actual position of the photosensor 3, the position of the Lx + n steps left from the point O, the point The position is left by m1 · S from PL.

Next, the carrier 4 is moved at a printing speed S to 2 ·
It is moved to the right by (Lx + n) steps (FIG. 4C).
The microprocessor 10 starts the sensor timer 13 when the carrier 4 is operated by Lx steps from the movement start during the operation of FIG. 4C, and when the output of the photo sensor 3 is switched from off to on. And the contents of the sensor timer 13 are read.
When this timer value is Tf, Tf is as follows: Tf = Txf + m1 + m2 + Nt. Here, Txf is the carrier 4 corresponding to the step command when the carrier 4 is moved rightward at the printing speed S.
Is the delay time. Nt is a value obtained by converting the number n of margin steps at the printing speed S into time. The timer value Tf includes the sensor-off error m1 and the sensor-on error m2, which have already become apparent. Nt is a known value. Therefore, Txf, which is the delay time when the carrier 4 moves to the right, can be obtained by the following equation obtained by modifying the equation.

Txf = Tf−m1−m2−Nt In FIG. 4C, the stop position of the carrier 4 and the point PR ₁
Is the position of the actual photosensor 3, the position right by Lx + n steps from the point O, and the position left by m1 · S from the point PR.

Next, the carrier 4 is moved at a printing speed S to 2 ·
It is moved to the left by (Lx + n) steps (FIG. 4D).
The microprocessor 10 starts the sensor timer 13 when the carrier 4 is operated by Lx steps from the movement start during the operation of FIG. 4D, and when the output of the photosensor 3 is switched from on to off. And the contents of the sensor timer 13 are read.
When this timer value is Tr, Tr is given by Tr = Txr + Nt. Here, Txr is the carrier 4 corresponding to the step command when the carrier 4 is moved to the left at the printing speed S.
Is the delay time. Therefore, Txr, which is the delay time when the carrier 4 moves to the left, can be obtained by the following equation obtained by modifying the equation.

Txr = Tr−Nt The delay time, Txf, and Txr of the right and left movements of the carrier 4 at the printing speed S are represented by stepping motors. 9 and the elastic deformation of the gear system 7 and the timing belt 8 such as backlash, backlash and elongation. Further, assuming that the sum of Txf and Txr obtained here is Td, Td is given by the following equation: Td = Txf + Txr = Tf + Tr−m1−m2− (2 · Nt) Then, based on the Td obtained here, drive correction is performed on the print driver 11 at the time of bidirectional printing to improve print quality. The print correction time T based on Td for performing the drive correction is expressed by the following equation.

T = Td−2 · Tp where Tp is the time from the start of driving by the print driver 11 to printing by the dot impact print head 2. .

The drive correction of the half T / 2 of the print correction time T for rightward printing and leftward printing, respectively, substantially shifts the position of the photosensor 3 and the printing position using the point O as a reference point. The right and left dot patterns can be printed without any deviation in dot alignment.
The print correction time T may be allocated to, for example, 3 / 4T in the right direction and 1 / 4T in the left direction, and drive correction may be performed at this rate when printing in the right and left directions. As described above, the print correction time T can be arbitrarily assigned.

In this series of correction operations, each time the microprocessor 10 generates a start timing, the series of correction operations is performed, and the print correction time T is updated.

The start timing is determined when the device temperature based on the temperature sensor 1 monitored by the microprocessor 10 shifts to an arbitrary temperature range.
In the case where the temperature is divided into regions of 10 ° C. like the temperature region shown in FIG.
Occurs when the temperature range shifts, such as when the device temperature shifts to 0 ° C. The activation timing is also generated after the activation timer 14 managed by the microprocessor 10 has elapsed for a given time. The generation of the start timing based on the start timer 14 is performed when the transition of the temperature region is not performed, for example, when an arbitrary set time is set to 30 minutes. This is done if no migration takes place.

In this embodiment, the case where the start timing is generated according to the combination condition of the apparatus temperature and the elapsed time has been described. However, the start timing may be generated according to either the apparatus temperature or the elapsed time. It is possible. For example, if only the apparatus temperature is followed, the temperature range may be small, for example, every 5 ° C.
Further, if only the elapsed time is to be followed, the set time may be set short, for example, to 10 minutes.

In this embodiment, a case has been described in which correction is performed during both rightward and leftward printing.
It is also possible to correct only for either rightward printing or leftward printing.

In this case, the drive correction may be performed during printing in either the right direction or the left direction without changing the print correction time T. Therefore, when drive correction is performed for rightward printing, printing is performed at a position on the right side of the position of the photosensor 3 and a printing position based on the point O,
If drive correction is performed for printing in the left direction, on the contrary, printing is performed at the left position.

In this embodiment, the carrier position detecting sensor is a transmission type photo sensor 3 and a member passing through the output switching position of the photo sensor 3 is a shielding plate 4.
Although the case of a has been described by way of example, the present invention is not limited to this, and the photosensor 3 is a reflection type photosensor, and the shielding plate 4
There is no problem even if a is composed of the reflection plate attached to the carrier 4.

Further, in this embodiment, a serial dot impact printer has been described as a serial dot printer, but other serial dot printers such as a serial ink jet printer and a serial thermal printer are known. The print correction method of the present invention can be applied to all of these known printers.

[0040]

As described above, according to the present invention, the carrier error of the carrier position detecting sensor is detected in advance in accordance with one of the change of the apparatus temperature and the elapse of the set time, or a combination of both. By detecting the delay time due to the actual movement error in the right and left directions, and correcting the printing timing during the right or left printing operation or both printing operations, the open-loop control type stepping motor can be used. Even when the carrier is driven, fluctuations in sliding resistance due to friction between the carrier bearing and the guide shaft due to fluctuations in device temperature and aging of the device, thermal expansion and contraction of the transmission member, and shape deformation due to friction, etc. Due to fluctuations in the amount of backlash and backlash, and fluctuations in the amount of elastic deformation due to changes in the characteristics of the transmission member. The ability to correct a delay amount between the command and the carrier positions can be dot alignment of the print in both directions printing is printed a dot pattern having an excellent quality. In addition, bidirectional printing can be performed instead of only one-directional printing in the past, and the throughput of the apparatus can be improved.

Further, it is possible to eliminate the adjustment of the variation in the delay amount between the step command and the carrier position, which is different between the apparatuses, thereby improving the workability. Moreover,
The configuration of the control circuit used for this purpose is simpler than that of the closed-loop control system, so that it is advantageous in terms of cost.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention.

FIG. 2 shows a time until light-emitting elements of the photosensor shown in FIG. 1 turn on due to light emission, a time until turning off due to light extinction, a time until turning on due to escape of a shielding plate, and a time until turning off due to entry of a shielding plate FIG. 5 is a diagram showing an example of a sensor error characteristic indicating a relationship with time.

FIG. 3 is an explanatory diagram of sensor error detection of the photo sensor according to one embodiment of the present invention.

FIGS. 4A to 4D are diagrams illustrating how carrier delay time is detected when a carrier moves according to an embodiment of the present invention. FIGS.

[Explanation of symbols]

 Reference Signs List 1 Temperature sensor 2 Dot impact print head 3 Photo sensor 4 Carrier 4a Shield plate 5, 6 Guide shaft 7 Gear system 8 Timing belt 9 Stepping motor 10 Microprocessor 11 Print driver 12 Switch 13 Sensor timer 14 Start timer 15 A / D conversion circuit

Claims (6)

(57) [Claims] 1. controlled by a microprocessor,
In a print correction method of a serial dot printer when printing is performed while moving a carrier equipped with a print head in a left-right direction by a stepping motor, a method is provided in which the carrier provided at one end of the printer device moves rightward and leftward. A carrier position detection sensor that detects a movement error in a right direction and a left direction; a member provided on the carrier and passing an output switching position of the carrier position detection sensor; and a right and left direction of the carrier by the carrier position detection sensor. Determining means for detecting a sensor detection movement error in the movement in the direction, subtracting the actual movement error of the carrier from the sensor detection movement error, and determining a constant sensor error according to the apparatus temperature; and a constant means according to the apparatus temperature. Detected by the sensor error and the carrier position detection sensor Correction means for preliminarily calculating and storing based on the sensor detection movement error and correcting the print timing in one of the right and left directions or both directions; A timing generation unit, and the printing correction time by the correction unit is updated by the start timing generated each time in accordance with one of the change of the apparatus temperature and the elapse of the set time, or a combination of both. A printing correction method characterized in that it is made as described above. 2. The carrier position detecting sensor is a transmission type photo sensor, and a member passing through the output switching position is a shielding plate formed of a part of the shape of the carrier. Print correction method described. 3. The printing method according to claim 1, wherein the carrier position detection sensor is a reflection type photo sensor, and the member passing through the output switching position is a reflection plate attached to the carrier. Correction method. 4. A position sensor sensitivity measurement circuit for automatically determining the sensitivity of an A / D conversion circuit, a temperature sensor, and the carrier position detection sensor, wherein the determination means for determining the constant sensor error according to an apparatus temperature. 2. The print correction method according to claim 1, comprising: 5. A switch for turning on and off a light emitting element circuit of the carrier position detecting sensor by a trigger of the microprocessor, a position sensor sensitivity measuring circuit, and a switch of the carrier position detecting sensor which is started by a trigger of the microprocessor. 5. The print correction method according to claim 4, further comprising a timer that stops when the voltage level of the light receiving element circuit reaches an arbitrary level. 6. The A / D converter according to claim 1, wherein
2. The print correction method according to claim 1, further comprising a conversion circuit, a temperature sensor, and a timer which is started by a trigger of the microprocessor and is stopped after a given time elapses.