JPS5887063A - Print position controlling system - Google Patents

Abstract

PURPOSE:To provide a print position control system enabling a printer to print images of high quality at a high speed without being influenced by errors of position detection by such an arrangement wherein errors of position detection attributable to the hunting etc. of a print head which makes reciprocatory movement, at the time of detection of moving positions are prevented by the use of print indexes which are provided at the same density as that of dots which are units of image elements to be printed and position indexes which are provided at an interval equivalent to a value obtained by multiplying the print indexes with a whole number. CONSTITUTION:Together with a position index corresponding to each print dot, position indexes 3b shall be provided as follows. The relation between the interval l of position indexes 3b and the interval of approaching distance l'2 shall be such that the interval of the position indexes 3b shall be made narrower than the auxiliary running distance l'2 at all times, and control of print position is accomplished by providing position indexes so that a carriage is caused to stop or return in the vicinity of the central part between a position index and an adjoining position index.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a print position control method during reciprocating movement of a print head in an impact printer, a non-impact printer, or the like.

Examples of impact printers include thermal printers and inkjet printers.Printing with these printers is performed with a carriage equipped with a print head placed opposite the print paper. The dots are moved back and forth in the horizontal direction, and a printing timing signal created using a method known as a trigger is used to drive wires and emit ink droplets.As a result, characters or figures are formed on the printer paper as a collection of dots. Therefore, the image quality of printed characters or figures is determined by whether or not the dot printing positions of wires and ink droplets can be accurately spaced during movement.

In the past, various proposals have been made regarding the generation method of the print timing signal to obtain good print image quality, and the first one is a method in which it is generated in synchronization with the rotation of the motor that is the drive source for the horizontal movement of the carriage. This is a method in which a low-level encoder is attached to the motor rotation shaft or a part of the transmission system, and the pulse signals generated by the rotation are basically used.

The second method is to correspond to the printing density as shown in FIG.
A film (printed index plate) 1 is provided over the entire printing width facing the moving direction of the carriage, and the markings 1a on the printed index plate 1 are read by optical or magnetic means. There is a method based on generating a print timing signal along with the movement.

However, these methods have the following problems. The biggest problem with the first method, which uses a rotary encoder as a printing index, is that it is not a method to directly detect the position of the printhead, so the rotary encoder cannot be used immediately! The problem is that the dot shift and color errors are large due to vibrations and slippage occurring in the transmission system interposed between IN11 and the horizontal movement of the carriage. This causes the image quality to be significantly degraded with respect to a change in e.g. Furthermore, since the encoder disk cannot be made too large, it is necessary to use a method of rotating the encoder several times or several tens of times for one scan of the rotor, resulting in a half-tube problem that complicates control.

On the other hand, in the second method, that is, the method using a printed indicator board installed along the running path, the dot spacing is usually i,,'i 20 inches (σ).
The width of indicators 1a and 1b is 1/60 inch or 1/12
0 inches. If the width of 1a and 1b is inner and the print timing signal is created, then d:
, the signal actually used as the print timing signal must be electrically processed to have a repetition frequency twice that of the repetition frequency of the read signal from the index plate 1, and therefore, rapid changes in the moving speed of the Yarishoji The dot spacing becomes uneven when the dot is moved or when the dot moves while tilting.

Therefore, it is better to provide an index with a width of 1/120 inch and to print all dots using the original timing signal read from the index, since it is possible to obtain a printing timing signal that corresponds to changes in the movement of the needle. Characters or figures with good image quality can be obtained.

On the other hand, in order to increase the overall printing speed of the printer, it is possible to print during both forward and backward scanning of the printer, and to use the shortest distance printing method, in which all print data in a line is printed at the point where printing is completed. Immediately stop the printing press, approach the printing start position or printing end position of the next line, whichever is closer, depending on the number of print data on the next line based on that point, and then move forward or backward from that position. A method has been proposed in which the overall printing speed is increased by minimizing wasted movement time in the margin area by performing printing while moving the paper ridge in the direction of the paper. When such a printing method is employed, it is essential to accurately detect the stop position of the carriage.

However, when using an index plate as shown in Fig. 1, due to the hunting of the index plate that occurs when the index plate is stopped and started, the sensor moves back and forth many times between the indicators 1a and 1b, and the generates a large number of signals, making it impossible to accurately detect the position of the carriage. In order to avoid this problem, conventionally, the index plate shown in FIG. 2 has been used. In other words, the indicators 2a and 2b correspond to the printing degree of dots, which are printing constituent units.
In addition, the position markers 3 are arranged at intervals equal to the width of the marker 2b and at bi-character unit intervals, that is, at intervals of 1710 inches. (The carriage is controlled so that it always stops at 1. Therefore, if there is a difference in the drive system, the carriage will actually stop after the stop 1 command is input from 1 to 1.) At 1, the distance is 11, that is, the run-up distance is 1 character. When the distance between the position indicators 3 becomes longer than 1, the distance between the position indicators 3 is determined to be approximately twice the run-up distance that can be kept almost constant by the drive system, etc. In other words, the position index interval is always determined from the approach distance: Widely installed 1. To control the movement, a stop command is input, the 7-carriage nozzle stops at the center of position index 3, and then it is accelerated by driving in the opposite direction and returns based on the detection of the first position index. ζ.As a result, the problem that occurred when using the index plate shown in FIG. 1 can be avoided.However, a new problem arises here.

In other words, in order to further improve the overall printing time, the speed of the paper cutter's movement Σ[ should be increased to speed <1. In this case, if conditions related to inertia, such as the heavy blade of the print head and the printing head, and the sliding resistance between the printing head and the moving support rod, are kept constant, the run-up distance will increase in proportion to the acceleration. In the method shown in Figure 2, (d, :lj) is placed at intervals twice the running distance.
Since the markers 3 are installed, the intervals between the position markers 3 will inevitably become wider in proportion to the longer run-up distance. As a result, as shown in No. 3M, if printing 4N ends immediately after passing the position indicator 3a, the conventional method, that is, the method of always setting the interval between the position indicators 3a at twice the interval of the approach distance 1, starts decelerating when it detects the first position index 3a' after printing ends I~7
Since this is from the point in time, the portion corresponding to e2 in FIG. 3 becomes the run-up distance. Therefore, this is the area where 6+&-I is not printed, and the longer this run-up distance becomes, the more this negative factor increases. Effect&j
reduce On the other hand, in order to keep this run-up distance constant even as the speed increases, it is necessary to increase the power of the drive source, that is, the motor.
Use l-rh to strengthen the braking force and 7: h, l'
No. l, is 1. As a result, a motor drive circuit and its power supplies tf and I are required to have extremely large capacities, and the cost and energy consumption inevitably decreases. An even bigger drawback is that a sudden braking force is constantly added to the dry spear, which increases the impact and vibration P and -υ applied to the head. For example, this force and vibration can cause air bubbles to enter the print head, especially in the case of an inkjet head or a specially designed inkjet head. The present invention was made to solve the above problem, and it uses a printing index that is equal to the dot density in units of printing pixels and an interval that is an integral multiple of this. To obtain an economical printer with excellent image quality that can perform high-speed printing without being affected by position detection errors caused by hunting, etc. when detecting the moving position of a print head that moves horizontally by using a position index provided in The present invention will be described in detail below with reference to the drawings.

41ffl (,) shows the method of installing position indicators in the present invention, and the indicators corresponding to each printed dot (corresponding to 2a and 2b in Fig. 2) are omitted. In other words, the position Interval e of index 3b and approach distance IA2・
The relationship with (a2・-42) is such that the distance l between the position markers 3b is always narrower than the run-up distance 7!2', and the carriage is Set the distance between position indicators to stop or turn around and drive! :i'! control Therefore, since there are multiple numbers of run-up distance 7!2 and the position phase included in the section):" a b, the print position control method using 'l?' is also the same as the method shown in Figure 2. It's coming.

In the present invention, hunting at the minimum interval stop or turning point of the place mark 3b (: ゛or mechanical factors)
'lfi (1?・'s thorough examination, etc. plus margin 1
study law in ~.

Next, referring to Part 6 and Part 1, the printing position control operation according to the invention will be explained. In fact, two optical sensors are installed on the Yarisoji, which has a mid-horizontal movement of 1゛·l.

In other words, the printing doso)! F-11't, fσ printing N,' (not shown in the 4th part, but shown in Fig. 2
This corresponds to a and 2b. ), corresponding to the integer multiple thereof, and determined by the previous dt1 method '+, i:: l- place 111' The sensor 12 for reading the index 3b is provided Ii -ru. The printing indexes 2a and 2b are read by the print sensor 11 using the printing start finger fan, and the print timing signal sequence (hereinafter referred to as "dot clock") generated by the waveform shaping circuit 13 is transmitted to the print I control circuit. 14 is copied (at -7, the characters, 2 figures, etc. corresponding to the print signal are printed I7. At this time, the position index 3b is read by the sensor 12 and the waveform is shaped into a waveform '41 by the R2 circuit 16. The created position timing signal-bow (hereinafter referred to as marker clock) is ignored.

When the forward printing is completed and a printing end command is issued, the printing operation is stopped, the counter 16 is counted, the dot clock starts counting from the next dot clock, and the marker clock is input from the waveform shaping circuit 16. Continue counting based on the number of items.

That is, the number of printed indicators included in 11 shown in FIG. 4 is counted. When the marker clock is input, counter 1
6 stops the count and holds its contents.

When the marker clock is generated, the carriage speed reduction device 17 starts decelerating the carriage, and the fourth run-up distance (corresponding to β2 of S1) starts. In this embodiment, a tacho generator is used to perform the stop position of the steering wheel. That is, the counter 18 determines the number of position indicators included in the run-up distance.
- is detected, and the stop state of the gear ring is detected by a tacho generator. Next, the carriage is shifted from deceleration to acceleration by the accelerator 20, and the counter 21 adds the position index in the acceleration run-up section ηWL, which is added in the deceleration run-up section to the number of position indexes. Susuwa 1. ) Matches the contents of the counter 18 i~. From the number of points, i1;l:4, that is, tons! - Count the clock with the counter 23.

This is a 22-digit matching circuit. ``..., the marker clock color / 1 ・ is 1 kunta 2 at `` Yayarinon acceleration run-up area exit''
12 may be added to the counter 18 without using the counter 18, and the contents of the counter 18 may be subtracted, and the counter 23 may be set when the contents of the counter 18 becomes ○.゛Counter 21 and coincidence circuit 22 are omitted.''
:3 I can do it.

When the counter 16 coincides with count and hold 1 to 1 on the forward pass, the matching circuit 24 controls the print control circuit 14 and prints the next dot t□. If printing is started on the return trip, the printing end point (-) on the outward trip can be matched with the printing start point on the return trip.

Note that in this embodiment, a tacho generator is used to detect the stopped state of the carriage, but it is possible to use the fact that the number of position indicators included in the run-up section is determined to be a constant number at the beginning of the design. It is possible to omit 2-,).

As is clear from the comparison of FIGS. 3 and 4, the printing position control method according to the present invention can reduce the overall printing time due to the high-speed movement of the carriage. In the conventional system shown in Fig. 3, in which the position index interval is twice the run-up distance, the distance between the position indexes becomes wider as the speed of the Yayari position increases, and the distance 7 is wasted.
! 1 becomes large, but if it is installed according to the method of the present invention, as shown in FIG. 4, the unnecessary movement distance β1 can be shortened to the minimum limit.

As shown in 1-1 above, the misfire 1411 eliminates the problem of shortening the printing time due to wasteful running that has occurred due to the high-speed movement of the carrier, and when the run-up distance is constant. Compared to the conventional method, there is a maximum of 4 points in wasted mileage of the Yayaringe! By setting r;6r, it is possible to effectively shorten the printing time. When the same position index intervals are used, 1: In the conventional method, the impact on the carriage increases as the run-up distance becomes extremely short.1. However, since the unexploded 11J (Yarere 1!) balance machine rJ to the Yayari position is alleviated, and there is no sudden braking, it is possible to provide an inexpensive device for the drive system.

[Brief explanation of drawings]

Figures 1 and 2 are a plan view of the position index interval in the conventional print position control system, Figure 3 (d) is an explanatory diagram of the operation of the position index section attached to the conventional position index board, and Figure 4 (1f) is the main view. An explanatory diagram of the operation of the position indicator unit used in the print position control system according to the invention, FIG. 6 (:1) is a block diagram of the print position control system in an embodiment of the invention. , 1b, 2a, 2b...
...Printed index section, 3a, 3b...Position, 111 marking section, 4a. 4b...Printed dot, β2. β2... Run-up distance, 11.12... Sensor, 14...
・Print control N path, 16.18.21.23・・Counter, 22124... Matching circuit. Iri (Names of 14 people fP Riju Toshi Nakao Haga 1 person Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] Transfer of the print head that moves back and forth 1. An index plate having a print mark formed in relation to the print density is provided facing in the direction of 1. The system is configured to generate a print timing signal by reading the same as the print head, and drive the print head using this print timing signal, and to set an indicator plate on an index plate that is an integral multiple of the interval between the print indicators and is narrower than the run-up distance when the print head is stopped. A position index of the interval is provided in parallel with the print index, and the print head is controlled to stop at an intermediate position between one of the position indexes and the adjacent position index, and the print head is moved in one direction i1). Read the first IM indicator from the end point of printing. Count the printing indicator read in the first section of the swivel and the position indicator in the run-up section. Count the position indicator after reversing the print head's moving direction. When the number matches the count I- number of the position index in the run-up section (1-), counting of the print index is started, and when this count number matches the count number of the print index of the first section, the next print index is started. A printing position control method characterized in that printing starts from when the reading occurs.