JPH024431B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a printing position control device during horizontal horizontal reciprocation of a print head in an impact type printer, a non-impact type printer, or the like.

Conventional Examples, Structures, and Problems There are known impact printers such as wire dot printers, and non-impact printers such as thermal printers and inkjet printers. Printing in these printers involves moving a carriage equipped with a print head back and forth in the horizontal direction while facing the print paper, and using a print timing signal generated by some method as a trigger to drive a wire or emit ink droplets, resulting in a dot. A collection of characters or figures is formed on printer paper. 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 at regular intervals during reciprocating movement.

In the past, various proposals have been made regarding the generation method of the print timing signal to obtain good print image quality.The first is a method in which it is generated in synchronization with the rotation of the motor, which is the drive source for the horizontal movement of the carriage. In this method, a rotary encoder is attached to the motor rotation shaft or a part of the transmission system, and the pulse signals generated by the rotation of the rotary encoder are basically used. The second method is to spread a film (printing index plate) 1 on which markings 1a are applied at intervals of printing density or an integer fraction of the printing density as shown in FIG. There is a method based on reading the markings 1a on the print index plate 1 by optical or magnetic means as the carriage moves, and generating a print timing signal.

However, these methods have the following problems. The biggest problem with the first method, which uses a rotary encoder as a print index, is that it does not directly detect the position of the carriage, so the transmission that intervenes between the rotary encoder mounting shaft and the horizontal movement of the carriage is the biggest problem. The problem is that the dot misalignment and position errors caused by vibration and slippage occurring in the system are large. This causes the image quality to deteriorate significantly over time. Furthermore, since the encoder disk cannot be made very large, it is necessary to use a method in which the carriage rotates several times or several tens of times for one scan, resulting in problems such as complicated control.

On the other hand, the second method, that is, the method of reading a printed index plate provided over the entire carriage path, solves most of the problems included in the first rotary encoder method, and is a method for generating print timing signals in a plane scanning method. This has the advantage of directly reading the absolute position of the scanning position of the carriage. However, a new problem arises here. In other words, the method of reading the printed index plates provided over the entire carriage travel path is based on the fact that when the printing density becomes higher than the printing density, the printed index plates 1a and 1b shown in FIG. When enlarging the printing area, this indicator plate must be made longer, which makes it extremely difficult to manufacture the printing indicator plate itself, or it is difficult to place the printing plate anywhere in relation to the carriage path over the entire printing area. There are problems such as the need to mount it in parallel with high accuracy and install it without bending.

Purpose of the Invention The present invention provides a printing position control method that improves the drawbacks of the method of reading the printed index board provided over the entire carriage travel path, and the production of the index board is easy no matter how enlarged the printing area is. The purpose is to easily solve problems such as mounting accuracy and deflection over the entire carriage travel path.

Composition of the Invention The composition of the printing position control system of the present invention consists of a printed index plate attached to a part of a carriage that moves horizontally left and right, and a plurality of sensors for reading this printed index plate fixedly arranged along the running path. It consists of a system,
The arrangement pitch of the sensors constituting this index detection system is such that the printed index plate is at a distance that can be detected by a maximum of two sensors at the same time.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIGS. 2 and 3 are conceptual diagrams showing an embodiment of the present invention, and a detailed explanation will be given below based on these diagrams.

In FIG. 2, the print head 6 is connected to the carriage 2.
When the carriage 2 moves, the print head 6 moves along the surface of the print medium 7. There is a printed index plate 3 at the end of the carriage 2.
is provided. The print indicator plate 3 is provided with a print indicator section that is marked in accordance with the print density, as in FIG. 1. 4-1, 4-2,
... 4-n are sensors for detecting markings on the printed index board 3, and a plurality of sensors are arranged along the travel path of the printed index board 3 as the carriage 2 moves. 5
is a print index detection system.

The key point of the present invention is to horizontally reciprocate the printed index plate 3 together with the carriage 2.
A plurality of sensors 4-1, 4-
2, .
The point is that there is always one marking on the print index plate 3, and the markings near both ends can be detected by two sensors at the same time.

For example, each sensor 4-1, 4-2,...4-n
If the pitch of each is set equal to the marking interval at both ends of the printed index on the printed index board 3, the markings at both ends will be detected simultaneously by two adjacent sensors, but other markings will always be detected by one sensor. Detected in As a result, the length of the printing index plate 3 corresponds to the pitch of the sensors 4-1, 4-2, . . .
It can be shortened in inverse proportion to the number of 4-n.

The following describes the operation when the pitch of each sensor 4-1, 4-2, .

The carriage 2 that has been scanned into the printing effective area detects the sensor 1 waveform shown in FIG. Shaping circuit 2
Output via 0. The printed index plate 3 is the sensor 4-
As the scanning progresses further from the section where only 1 has passed, the printed index plate 3 straddles the sensors 4-1 and 4-2, and the sensor 4-1 and the adjacent sensor 4-2 read the printed index plate 3. Signals from sensor 1 and sensor 2 are output simultaneously. (section corresponding to L in Figure 3b). The signals from these two sensors 4-1 and 4-2 can be outputted as read signals that almost match each other by adjusting the spatial phase of each sensor when configuring the index detection system 5. 3
The OR gate 30 shown in Figure a makes it possible to create a continuous timing pulse train (see Figure 3b). It goes without saying that the spatial phase adjustment of each sensor can be carried out by making the interval between each sensor an integral multiple of the interval between the markings on the printed index plate 3. Further, when the carriage 2 is scanned, the sensor 4-1 passes and the timing pulse train is formed only from the sensor 4-2. As the sequential scanning progresses, the printed index plate 3 attached to the carriage 2 is successively scanned by the sensor 4-2,
4-3,...4-n, the timing pulse train is formed at the same time from sensor 4-1 to sensor 4-n.
2, 4-3, . . . 4-n and the forming components are transferred.
The signals read from each sensor 4-1, 4-2,...4-n are passed through a waveform shaping circuit 20 to an OR gate 3.
A print position timing pulse signal can be formed by adding it to 0 and combining it.

According to such a configuration, the length of the printed index plate 3 may be short, and by shortening the pitch of the sensor, the printed index plate 3 can be shortened accordingly. Furthermore, even if the print area length becomes longer, it is only necessary to increase the number of sensors, so there is no need to lengthen the print index plate 3. Therefore, the printing index plate can be manufactured very easily, and the mounting accuracy can also be increased. Printing density can be increased by arranging the sensors at a high density within the reading resolution range.

Effects of the Invention As described above, the present invention provides a print index plate on a carriage equipped with a print head, reads the print index plate using a plurality of sensors arranged along the carriage travel path, and generates a print timing pulse in response to the print index plate. In the print position control device configured to generate the print position, the length of the print index plate can be extremely short regardless of the print area length, and the difficulty in manufacturing is greatly reduced. At the same time, problems such as deflection regarding the mounting of the printed index plate can be completely ignored.

On the other hand, in terms of cost, the printed index plate can be made extremely short, which is very effective.

[Brief explanation of drawings]

FIG. 1 is a plan view of the print index plate, FIG. 2 is a schematic configuration diagram of the print position control device according to the present invention, FIG. 3a is a circuit block diagram of the print position control device according to the present invention, and FIG. 3b is a FIG. 3 is a signal output waveform diagram corresponding to the block diagram in FIG. 1...Printed index plate, 1a, 1b...Printed index portion, 2...Carriage, 3...Printed index plate, 4-
1, 4-2,...4-n...sensor, 5...printing index detection system, 6...printing head, 7...printing medium,
20... Waveform shaping circuit, 30... OR gate.

Claims (1)

[Claims] 1. A reciprocating carriage carrying a printing head, a printing indicator plate provided on the carriage and marked according to the printing density, and a printing indicator plate arranged along the running path of the carriage and marking the markings on the printing indicator plate. multiple sensors that read markings;
an OR gate for synthesizing the outputs of the plurality of sensors, the length of the printing index plate is determined corresponding to the arrangement pitch of the plurality of sensors, and the length of the printing index plate is determined according to the arrangement pitch of the plurality of sensors, and The arrangement pitch of the markings is an integral multiple of the interval between the markings on the printing indicator plate, and the two sensors are determined to simultaneously detect markings near both ends of the printing indicator plate. Position control device.