JPH10250170A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce shift of printing position even when the traveling speed of a print head is different in the direction of going path and in the direction of returning path. SOLUTION: A controller is provided with a function for providing a print head 2 with a print timing signal PTS generated independently in the direction of going path and in the direction of returning path. More specifically, PTS determined depending on the traveling direction and the printing position are stored in a memory and a corresponding PTS is read out when a traveling direction is detected. It is then fed to the print head 2 at a timing for reducing relative positional shift caused by the difference of traveling speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial scanning type printing apparatus which performs reciprocal printing by reciprocating a carriage having a print head mounted thereon in a main scanning direction (line direction) via a belt. The present invention relates to a printing apparatus having a mechanism for determining a print timing in a forward direction and a return direction on a line each time a carriage reciprocates.

[0002]

2. Description of the Related Art A printing apparatus capable of reciprocal printing, for example, a serial printer, has a carriage driving mechanism for reciprocating a carriage on which a print head is mounted in a main scanning direction (line direction), and a printing paper in a sub-scanning direction (main scanning direction). (A direction orthogonal to the direction) and a controller for controlling each of the above mechanisms.

FIG. 9 shows a main configuration of a serial printer of this type. In this serial printer, the carriage drive mechanism slidably moves a carriage 92 in which the ends of one belt 94 are fixed to opposite ends in the running direction on guide rods 93 arranged in parallel with the running direction. Support,
Further, the belt 94 is laid in parallel with the guide rod 93 between a driven pulley 95 and a driving pulley 96 attached to a rotating shaft of a carriage motor (CR motor) 97, and the CR motor 97 is driven. By doing so, the carriage 92 reciprocates in the main scanning direction via the belt 94. The paper feed mechanism includes a paper feed motor (PF motor) 9 for driving a paper holding unit (not shown) for temporarily holding print paper in the sub-scanning direction.
8, and by driving this PF motor 98,
The printing surface of the printing paper is relatively displaced with respect to the carriage 92.

A controller 99 in FIG. 9 is, for example, a programmed computer, and controls the above-described carriage driving mechanism and paper feeding mechanism, and controls a print head mounted on the carriage 92.

The contents of control of the carriage driving mechanism mainly include supplying power to the CR motor 97 and
7 is rotated forward or backward, thereby enabling the carriage 92 to reciprocate in the main scanning direction via the belt 94 and the guide rod 93. On the other hand, the content of the control of the paper feed mechanism is to supply power to the PF motor 98 at regular intervals in conjunction with power supply to the CR motor 97, and to rotate the PF motor 98 at a constant pitch in the sub-scanning direction. Thus, it is possible to feed the printing paper set at a constant interval with the carriage 92.

[0006] The contents of the control of the print head include the carriage 9
2. A print timing signal (hereinafter, PTS) is output to the print head for each of the outward travel and the return travel, and printing based on print data (print request command and data, the same applies hereinafter) on print paper by the output timing of the PTS. Is to make it possible. In other words, if the serial printer is of the ink jet type, characters are formed by discharging ink onto the printing paper, and if the serial printer is of the heat-sensitive or thermal transfer type, the characters are formed directly on the printing paper or through a ribbon. Etc. are formed. The output point of the PTS is a point in time when the CR motor 97 enters a constant-speed rotation state after a lapse of a fixed time from the start of rotation of the CR motor 97 in both the forward path and the return path. The speed was treated as the same for the forward travel and the return travel.

[0007]

The belt 94 used in the carriage driving mechanism shown in FIG.
Is always deformed (expanded or contracted) when the carriage 92 is moved, regardless of its material. The amount of deformation depends on the material and shape of the belt 94, but the running direction and running position of the carriage 92, that is, the carriage 92
It also depends on how far you are from 6. The difference in the amount of deformation of the belt 94 appears specifically as a difference in the traveling speed of the carriage between the forward direction and the backward direction. However, in the controller 99, the PTS is output to the print head at the same timing in the forward pass direction and the return pass direction, so that the print position in the sub-scanning direction does not match during reciprocal printing. Deviation is a problem.

This problem will be specifically described with reference to FIGS.

FIG. 10A shows a state where the carriage 92 in the vicinity of the driven pulley 95 travels in the direction of the driving pulley 96 via the belt 94 in the carriage mechanism shown in FIG. FIG. 11A is a schematic diagram showing a state in which the carriage 92 travels from the vicinity of the driving pulley 96 toward the driven pulley 95, that is, the backward direction. In the figure, FR is a driving force required when the carriage 92 is caused to travel forward, and F
L is a driving force required when the carriage 92 travels backward. k11 and k21 are the elastic strengths of the belt 94 on the side where the carriage 92 exists when the driven pulley 95 is viewed from the driving pulley 96 (the degree of difficulty in deformation (also referred to as a spring constant, the same applies hereinafter)), and k12 and k22. Is the elastic strength of the belt 94 on the side where the carriage 92 does not exist.
Is the scheduled printing area, ΔxL is the amount of deformation of the belt 94 when starting the forward travel, and ΔxR is the amount of deformation of the belt 94 when starting the backward travel.

The schematic diagram of FIG. 10A is mechanically equivalent to that of FIG. In other words, the driving force FR at the time of starting the forward traveling is equal to the elastic strength 2 because the belt length of the elastic strength k11 portion and the elastic strength k12 portion are substantially equal.
This is a force that causes a deformation amount of ΔxL on the belt 94 of k11 (or 2k12), and can be approximated by the equation “FR = 2k11 · ΔxL”. Similarly, the schematic diagram of FIG. 11A is equivalent to the schematic diagram of FIG. 11B, and the driving force FL at the time of starting the backward traveling is such that the belt length of the portion where the elastic strength is k21 is equal to that of the elastic strength. Because it is much shorter than the k22 part,
It can be approximated by the equation of “FL = k21 · △ xR” (k21 is larger than k22). The carriage 92 at this time
The relationship between the position (CR position) and the elastic strength of the belt 94 is normally as shown by the solid line in FIG. 12, that is, the point where the elastic strength is the weakest in the scheduled printing area Lp (the amount of deformation is The carriage 92 is displaced from the position where the elastic strength is increased from the position where the elastic strength is increased to the direction where the elastic strength is weakened. Will be displaced.

The actual travel distance of the carriage 92 at the time of printing is determined by the amount of deformation {xL, {
xR, the traveling distance in the forward direction is “Lp + △ xL− △ xR”, and the traveling distance in the backward direction is “Lp
+ △ xR- △ xL ”. Now, for the sake of convenience, assuming that “△ xL− △ xR” is a constant α determined according to the type of the belt 94, the traveling distance in the outward direction is “L
p + α ”, and the traveling distance in the backward direction is represented by“ Lp−α ”. This means that the traveling distance in the forward direction is always longer than the traveling distance in the backward direction. In contrast,
Since the forward traveling time and the backward traveling time are common, the traveling speed in the forward traveling direction is eventually higher than the traveling speed in the backward traveling direction.

As described above, the traveling speed of the carriage 92 is different between the forward direction and the backward direction. However, in the conventional serial printer, since the output timing of the PTS is the same in the reciprocating direction, as shown in FIG. When printing back and forth,
The relative printing positions (p11 and p21, p12 and p22 ...) in the sub-scanning direction are shifted. Such a problem commonly occurs in printing apparatuses having the above-described carriage driving mechanism.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the deviation of the printing position in the sub-scanning direction in a printing apparatus having an element that makes the traveling speeds of the carriage in the forward and backward directions different.

[0014]

According to a first aspect of the present invention, there is provided a printing apparatus comprising: a carriage driving mechanism for reciprocating a carriage on which a print head is mounted in a main scanning direction; PTS for defining
And a printing timing signal generating means for generating the print timing, wherein the following points have been improved in a printing apparatus in which the traveling speeds of the carriage in the forward and backward directions are different from each other.

[0015] (1) The print timing signal generating means is configured to control the at least one of the PTSs in the forward and backward directions of the carriage at a timing for reducing a relative print position shift caused by a difference in reciprocating travel speed of the carriage. It was configured to supply to. As an example of the configuration, a PTS determined for each of the traveling direction of the carriage and the expected print position is stored in a data storage memory, and when the traveling direction of the carriage is detected, a corresponding PTS is searched from the data storage memory. Control means for changing the relative print position in the forward and backward directions of the carriage by the searched PTS.

(2) Instead of the above configuration (1), means for detecting the traveling direction of the carriage, and PTS generated at a fixed timing in accordance with the detected traveling direction, and reciprocation by the print head Timing correction means for bringing the relative printing positions during running closer to each other. The timing correction means includes, for example, a signal correction coefficient storage memory storing a PTS correction coefficient determined for each of the traveling direction of the carriage and a scheduled printing position, and storing the signal correction coefficient when detecting the traveling direction of the carriage. A memory control means for searching for a corresponding correction coefficient from a memory, wherein the PTS is corrected by the searched correction coefficient so as to change respective relative printing positions in the forward and backward directions of the carriage. Configure.

(3) Instead of the configuration of the above (1), means for detecting the traveling direction of the carriage, wherein the traveling speed of the carriage is corrected in accordance with the detected traveling direction and generated at a constant timing. Speed correction means for making the relative print position during reciprocation based on the print timing signal close to the same. The speed correction means includes, for example, a speed correction coefficient storage memory storing a correction coefficient for the traveling speed of the carriage determined for each of the traveling direction of the carriage and a scheduled printing position, and a memory for detecting the traveling direction of the carriage. And a memory control means for searching for a corresponding correction coefficient from a speed correction coefficient storage memory, so that the traveling speed of the carriage in the forward direction and the return direction is changed by the searched correction coefficient. .

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a serial printer will be specifically described below with reference to the drawings. The carriage drive mechanism and the paper feed mechanism of the serial printer according to this embodiment are the same as those shown in FIG. In other words, the carriage on which the print head is mounted is slidably supported on the guide rods, a part of the belt stretched in parallel with the guide rods is fixed to the carriage, and the belt is driven by the CR motor to reciprocate the carriage. It is designed to run.

FIG. 1 is a configuration diagram of a main part of a control system of the serial printer, and mainly shows a connection relationship between the controller 1 and peripheral elements.

The controller 1 is a programmed computer (CPU) that controls output of print data and PTS to the print head 2, controls a CR motor driver 3 for driving a CR motor, and controls a PF motor. And controls the PF motor driver 4 for driving the motor. In the RAM 5, for example, print data based on a print job sent from a host computer is recorded, and the controller 1 can read out the data at any time. The ROM 6 has a PTS common to serial printers of the same type, various necessary correction coefficient data, and EEP.
The RPM 7 stores data unique to each printer, and the stored data can be read out at any time when the control process is executed.

A program for giving the above-mentioned control function to the controller 1 can be recorded and distributed on a machine-readable recording medium such as a flexible disk or the like. At any time in the printer's internal memory,
A computer (CPU) that can access the memory can read out and execute the program at any time.

[0022]

【Example】

(First Embodiment) FIG. 2 is a diagram showing an example of functional blocks of the controller 1 in a case where the output timing of the PTS is made independent in the forward direction and the backward direction in the serial printer having the configuration of FIG. In this case, the controller 1 functions as a print timing signal generation unit.

The controller 1 in this embodiment includes a main control section 11 for controlling the inside of the controller while controlling a carriage driving mechanism and a paper feeding mechanism in cooperation, a main scanning control section 12 for controlling the CR motor driver 3, and a PF. A sub-scanning control unit 13 for controlling the motor driver 4; a PTS output unit 14 for outputting the PTS to the print head 2;
A print data output unit 15 for outputting the print data obtained from M5 to the print head 2; a movement detection unit 1 for detecting the traveling direction of the carriage from the control contents of the main scanning control unit 12
6. It has a memory control unit 17 that reads data stored in the ROM 6 and the EEPROM 7 based on the detection result of the movement detection unit 16 and outputs the data to the PTS output unit 14.

The ROM 6 stores a PTS corresponding to the printing speed, that is, the running speed of the carriage. FIG.
FIG. 3 is a diagram showing an example of the contents of a ROM 6, in which PTSs d11 to d1n and d21 to d2n determined according to the traveling speed of the carriage are stored.

The EEPROM 7 stores P at each relative printing position.
The correction coefficient of TS is stored. Relative printing position L1-L
n is an individual print position in the print area Lp described above. This correction coefficient individually corrects the stored data in FIG. 3 according to the characteristics of the individual carriage driving mechanisms, for example, the elasticity of the belt, and is, for example, relative to a reference value “1” that does not require correction. Expressed by value.
FIG. 4 shows an example of the contents of data stored in the EEPROM 7. It should be noted that individual PTSs may be regenerated based on the correction coefficients and stored in the EEPROM 7 in advance. The data stored in the EEPROM 7 can be rewritten.
The contents of the EPROM 7 may be individually updated to appropriately match the characteristics of the actual carriage driving mechanism.

Next, the operation of the serial printer according to this embodiment will be specifically described.

When the CR motor driver 3 and the PF motor driver 4 are controlled by the main scanning control unit 12 and the sub-scanning control unit 13, the traveling direction detecting unit 16 detects the traveling direction of the carriage. The memory control unit 17 stores the PTS and the correction coefficient according to the traveling direction of the carriage in the ROM 6 and the EE.
The data is read from the PROM 7 and sent to the PTS output unit 14. P
The TS output unit 14 supplies the input PTS to the print head 2 and causes the print head 2 to perform printing based on print data on a printing paper (not shown).

In this way, even if there is a difference between the forward traveling speed and the backward traveling speed of the carriage when performing reciprocal printing, the PTS set according to the speed difference is supplied to the print head. As shown in FIG. 5, the relative print positions (p11 and p21, p12 and
22...) Can be matched. In FIG. 5, a dashed line indicates a relative printing position in a conventional printer, and a solid line indicates a relative printing position according to this embodiment.

It should be noted that the PTS during the reciprocation may be generated as it is conventionally (at a constant timing), and the PTS may be corrected for each carriage traveling direction and printing position. In this case, the controller 1 functions as timing correction means. And for that, ROM
6 and the data stored in the EEPROM 7 are stored not as the contents shown in FIGS. 3 and 4, but as signal correction coefficients for making the PTS close to the contents shown in FIGS. Then, the memory control unit 17 reads out the corresponding signal correction coefficient according to the traveling direction of the carriage, and outputs the signal correction coefficient to the PTS output unit 14.
The corrected PTS is output to the print head 2.

In this embodiment, the relative print positions in the respective directions are matched by adjusting the output timing of the PTS when the vehicle travels in both the forward and backward directions. By adjusting only the relative printing position in one direction, the relative printing position in the other direction may be matched.

(Second Embodiment) FIG. 6 shows a serial printer having the configuration shown in FIG.
Assuming that S is the same (constant timing),
This shows an example of a configuration in a case where the traveling speed of the carriage is corrected so that the relative printing positions during reciprocating traveling by the print head are brought close to the same. In this case, the controller 1 is caused to function as speed correction means. The main control unit 11, the main scanning control unit 12, the sub-scanning control unit 13, the PTS output unit 14, and the movement detection unit 16 are the same as those in the first embodiment, and the PTS output unit 24 and the memory control unit 27 The PTS output unit 14 and the memory control unit 17 prepared in the embodiment have basically the same functions.

In this embodiment, a carriage speed data value corresponding to the printing speed is stored in the ROM 6 for each carriage speed. Further, the EEPROM 7 stores a speed correction coefficient specific to the printer. Then, the data read from the ROM 6 or the EEPROM 7 by the memory control unit 27 is sent to the main scanning control unit 12, and the main scanning control unit 12 performs CR based on the carriage speed data based on the printing speed and the speed correction coefficient based on the printing position and the printing direction. The control amount of the motor driver 3 is configured to be corrected. At this time, the speed correction coefficients e11 to e1n and e21 to e2n in both directions may be read out and sent to the main scanning control unit 12. However, usually, the speed correction coefficients in only one direction are adopted, and the carriage in that direction is used. Is made to approach the traveling speed in the other direction.

The speed correction coefficient can be obtained, for example, as follows.

As described above, the traveling distance of the carriage in the forward direction is "Lp + α", and the traveling distance of the carriage in the backward direction is "Lp-α". Therefore, between the traveling speed v1 in the forward direction and the traveling speed v2 in the backward direction, “T
= (Lp + α) / v1 = (Lp−α) / v2 ”. Therefore, the parameter coefficient K that satisfies “v1 = Kv2” is used as the correction coefficient of the printer in the EE.
It is stored in the PROM 7.

Next, the operation of the serial printer according to this embodiment will be specifically described.

When the CR motor driver 3 and the PF motor driver 4 are controlled by the main scanning control unit 12 and the sub-scanning control unit 13, the traveling direction detecting unit 16 detects the traveling direction of the carriage. The memory control unit 27 reads out the speed correction coefficient or the speed correction coefficient and the correction coefficient according to the traveling direction of the carriage, and sends the read speed correction coefficient and the correction coefficient to the main scanning control unit 12. The main scanning control unit 12 controls the CR motor driver 3 based on the speed correction coefficient to correct the traveling speed of the carriage in the forward direction and the traveling speed in the backward direction. PTS output unit 24
Outputs the PTS to the print head at a point in time when a certain amount (time) is delayed from the phase switching timing of the CR motor acquired from the main scanning control unit 12 or the main control unit 11 in both the forward direction and the backward direction.

According to such a control procedure, as shown in FIG. 8, the forward traveling speed and the backward traveling speed of the carriage can be made close to the same, so that the output timing of the PTS remains the same as before. The relative printing positions (p11 and p21, p12 and p22 ...) in the sub-scanning direction can be matched.

In each of the above embodiments, the relationship between the carriage position and the elasticity of the belt is indicated by the solid line in FIG. This is an example in which the carriage 92 is displaced in a direction in which the strength is increased, and the carriage 92 is displaced in a direction in which the elastic strength is weakened from a position having the highest elastic strength during the backward traveling, as shown by a broken line in FIG. If it is possible to approximate that the elastic coefficient is linearly converted between the carriage positions p1 to pn, the correction coefficients shown in FIGS. 4 and 7 need not be provided for each relative printing position, but one for each carriage speed. And the control content is further simplified.

[0039]

As is apparent from the above description, according to the printing apparatus of the present invention, even when the carriage has an element for making the traveling speed different in the forward and backward directions, the traveling speed in each direction is different. PTS to print head according to difference
Is automatically corrected or the running speed is controlled so as to approach the same, so that there is an effect that the deviation of the relative printing position in the sub-scanning direction is reduced. This enables high quality printing.

In addition, PTS and various correction data are stored in a memory in advance, and the stored data is read out in accordance with the traveling direction of the carriage, so that necessary data can be quickly obtained and controlled. There are advantages that can be used.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of a control system of a serial printer to which the present invention is applied.

FIG. 2 is a diagram illustrating an example of a functional block configuration of a controller when adjusting the output timing of a PTS during reciprocal printing.

FIG. 3 is a diagram illustrating RO in adjusting the output timing of PTS.
Explanatory drawing which shows the example of the content stored in M.

FIG. 4 is an explanatory diagram showing an example of contents stored in an EEPROM.

FIG. 5 is an explanatory diagram of the timing of reciprocal printing when the output timing of PTS is adjusted, and the upper part shows an example of traveling on the forward path, and the lower part shows an example of traveling on the return path.

FIG. 6 is a diagram illustrating an example of a functional block configuration of a controller when adjusting a traveling speed of a carriage during reciprocal printing.

FIG. 7 is an explanatory diagram showing an example of contents stored in a ROM when adjusting a traveling speed.

FIG. 8 is an explanatory diagram of the timing of reciprocal printing when the traveling speed of the carriage is adjusted, and the upper part shows an example during forward traveling, and the lower part shows an example during backward traveling.

FIG. 9 is a schematic explanatory view of a carriage driving mechanism of a serial printer to which the present invention is applied.

FIG. 10A is a schematic diagram illustrating a state of a carriage driving mechanism at the start of a forward traveling, and FIG. 10B is a diagram in which this state is dynamically replaced.

11A is a schematic diagram illustrating a state of a carriage driving mechanism at the start of a return traveling, and FIG. 11B is a diagram in which this state is dynamically replaced.

FIG. 12 is a diagram illustrating a relationship between a position of a carriage and an elastic strength of a belt.

FIG. 13 is an explanatory diagram of reciprocal printing timing in a conventional serial printer of this type.
The lower part shows an example when the vehicle is traveling backward.

[Explanation of symbols]

 1,99 controller 2 print head 3 CR motor driver 4 PF motor driver 5 RAM 6 ROM 7 EEPROM 11 main control unit 12 main scan control unit 13 sub scan control unit 14, 24 PTS output unit 15 print data output unit 16 running direction detection Unit 17, 27 memory control unit 92 carriage 93 guide rod 94 belt 95 driven pulley 96 drive pulley 97 CR motor 98 PF motor

Claims (6)

[Claims] A carriage drive mechanism for reciprocating a carriage on which a print head is mounted in a main scanning direction; a print timing signal generating means for generating a print timing signal for determining a print timing of the print head during travel; A printing apparatus in which the traveling speed of the carriage in the forward direction and the traveling speed in the backward direction are different from each other, wherein the print timing signal generating means outputs at least one of the print timing signals in the forward direction and the backward direction by the traveling speed difference of the carriage. A printing apparatus configured to supply the print head with a timing at which a relative printing position shift caused by the printing head is reduced. 2. The printing timing signal generating means includes: a data storage memory storing the printing timing signal determined according to a traveling direction of the carriage and a scheduled printing position; A memory control means for searching for a corresponding print timing signal from a data storage memory, wherein the relative print position in the forward and backward directions of the carriage is changed by the searched print timing signal. The printing apparatus according to claim 1, wherein: 3. A carriage driving mechanism for reciprocating a carriage on which a print head is mounted in a main scanning direction, and a print timing signal generating means for generating a print timing signal for determining a print timing of the print head during traveling. A printing apparatus having different traveling velocities in a forward direction and a backward direction of the carriage, wherein: a means for detecting the traveling direction of the carriage; and And a timing correcting means for correcting the relative print position of the print head during reciprocation by the print head to make the relative print position the same. 4. The apparatus according to claim 1, wherein said timing correction means includes a signal correction coefficient storage memory for storing a correction coefficient of said print timing signal defined for each of a traveling direction of said carriage and a scheduled printing position, and detecting a traveling direction of said carriage. And a memory control means for searching for a corresponding correction coefficient from the signal correction coefficient storage memory, so that the relative printing position in the forward and backward directions of the carriage is changed by the searched correction coefficient. The printing apparatus according to claim 3, wherein the printing apparatus is configured as follows. 5. A carriage driving mechanism for reciprocating a carriage on which a print head is mounted in a main scanning direction, and a print timing signal generating means for generating a print timing signal for determining a print timing of the print head during traveling. A printing device having different traveling velocities in the forward and backward directions of the carriage, wherein: a means for detecting the traveling direction of the carriage; and a method of correcting the traveling speed of the carriage in accordance with the detected traveling direction to be constant. A printing device comprising: a speed correction unit that makes the relative printing position during reciprocation based on the printing timing signal generated at a timing close to the same. 6. The speed correction means detects a traveling direction of the carriage and a velocity correction coefficient storage memory which stores a correction coefficient of the traveling velocity of the carriage defined for each of the traveling direction of the carriage and a scheduled printing position. Memory control means for searching for a corresponding correction coefficient from the speed correction coefficient storage memory, and changing the traveling speeds of the carriage in the forward direction and the backward direction according to the searched correction coefficient. 6. The printing apparatus according to claim 5, wherein the printing apparatus is configured as follows.