JPS59123676A - Position detector for dot line printer - Google Patents

Abstract

PURPOSE:An inexpensive titled detector stable to noise and not requiring any adjusting work, wherein a detecting shutter plate is provided at the first group of printing elements, while a photoelectric detector is provided at the second group of printing elements, and the width of slit form holes of the shutter plate is set to be large. CONSTITUTION:The first and second group 1a, 1b of the printing elements 1 are faced respectively to printing mediums 2a, 2b, and are reciprocated by guiding along a guide shaft 6 in the longitudinal direction. The detecting shutter plate 10 is provided as one body with the first group 1a of the printing elements, while the photoelectric detector 11 is provided as one body with the second group 1b, and the groups 1a, 1b of the printing elements are oppositely moved by oscillating cams 9a, 9b. Since both of the groups are relatively moved and a section indicated by an arrow C is moved by an amount equal to 2 times of the displacement of the printing element groups, the pitch of the slit form holes of the plate 10 can be set to be 2 times of the dot pitch P, a sufficient quantity of light can be processed by the detector 11, and stability of the position detector to noise, disturbing light or the like can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a detection device for a dot line printer. Specifically, the present invention relates to an improvement of a position detection device for a printing element of a Tonto line printer.

A dot line printer creates horizontal dots by reciprocating a group of printing elements arranged in a straight line using a rocking mechanism, while forming vertical dots by transporting the printing medium. It is designed to be configured and printed. A position detection device for controlling the dot position in the lateral direction is provided. FIG. 6 shows a schematic diagram of a position detection device for a conventional dot line printer. Print element 1
A printing element group having five 01 oscillates between arrows A to perform dot printing, 1o2 is a detection shielding plate with a slit-shaped hole attached integrally with the printing element group, and 106 is a light emitting plate. It is a photoelectric detector consisting of an element and a light receiving element, and is used to extract a signal for controlling a predetermined dot position. However, in such a position detection device, the pitch of the dots printed and the pitch P of the slit-like holes provided in the detection shielding plate are the same size, for example, about 0.4 degrees. Therefore, the width and dimension of the slit-like hole is also 02mm.
/L, the amount of light that reaches the photoelectric detector is small, requiring an amplifier circuit, and it also has the disadvantage of being susceptible to noise such as noise and disturbance light. As a countermeasure, as in the example of the position detection device shown in FIG. 4, photoelectric detectors 106 are arranged at two locations, and a detection shielding plate 202 is provided with slit-shaped holes that are shifted by one pitch in correspondence with each photoelectric detector. There is also a method of outputting a signal for predetermined dot position control by moving the dot in the direction of arrow A. In this example, the pitch of the slit-like holes in the detection shielding plate is twice the pitch P of the dots, so the width of the holes can be increased and a sufficient amount of light can be delivered to the photoelectric detector. However, since such a position detection device has photoelectric detectors in two locations, it becomes an expensive device, and the relative position of each detection must be fully adjusted to adjust the dot pitch P.
This had the disadvantage that it required work to match the

The present invention eliminates these drawbacks, and provides a position detection device for the printing element group of a dot line printer that is highly reliable and resistant to noise such as clumps and ambient light. The purpose of the present invention is to provide a position detection device.

1 and 2 show one embodiment of the present invention; FIG. 1 shows a plan view of a dot line printer, and FIG. 2 shows a sectional view of the same printer.

To explain in detail using figures, a dot line printer according to an embodiment of the present invention is particularly applied to an ECR (electronic cash register) printer, and prints on two print media: receipt paper and journal paper. be able to. 1 is a printing element having one dot wire in the center, and five printing elements are arranged in a straight line to form printing element groups 1a and 1b. And a printing element group 1a in which the above-mentioned printing elements 1 are assembled
, 1b are respectively provided facing the print media 2a, 21) arranged at two locations. each print medium 2a,
2k), a predetermined transfer is performed by a paper feed device (not shown) by a paper presser roller 4 pressed against a paper feed roller. Further, each printing element group 1a, 1b is integrally attached to a carriage 5a, 5b, and a guide shaft 6 is attached to the carriage 5a, 5b in the longitudinal direction.
It is possible to move back and forth guided by. carriage 5
a, 5btd are engaged via guide pins 7 with swing cams 9a and 9b, which are decelerated to a predetermined rotation ratio by a motor 8, respectively. Each of the swing cams 9a and 9b has a spiral cam groove and rotates to move the first group 1a of printing elements 1a and the second group 1b of printing elements along with the carriages 5a and 5b in the direction of arrows A and B. The sections are oscillated so that their phases are opposite to each other. Since the first group 1a and the second group 1b of printing elements connected to such a swing mechanism have swing phases opposite to each other, vibration of the printer can be prevented. Then, the first group 1a of the printing elements that moves reciprocally
If the detection shielding plate 10 is installed integrally with the second group 1b and the photoelectric detector 11 is installed integrally with the second group 1b, there will be no relative movement between the two. The pitch of the slit-like holes in the plate can be set to twice the dot pitch P.

As described above, the present invention provides a tontoline printer in which a first group and a second group of printing elements are provided on printing media arranged at two locations, and are connected by a swinging mechanism such that the phases of each are opposite to each other. By providing a detection shielding plate in the first group of printing elements and a photoelectric detector in the second group, the width of the slit-shaped hole in the detection shielding plate can be increased, and the amount of light from the photoelectric detector can be obtained sufficiently. It is highly reliable and is resistant to noise and ambient light. Furthermore, unlike in the past, two photoelectric detectors are not used and adjustment work is not required, making it possible to provide an inexpensive position detection device for a dot line printer, thereby achieving the original purpose.

Fig. 1 is a plan view of a dot line printer according to an embodiment of the present invention, Fig. 2 is a sectional view of the dot line printer, Fig. 5 is a schematic diagram of a position detection device of a conventional dot line printer, and Fig. 4 is another example. The conventional position detection device of the same printer.

ia, 1b are the first group and second group of printing elements 2 are printing media; 6 is a paper feed 90; 4 is a paper press roller; 5 is a carriage 6 is a guide shaft; 7 is a guide pin 9a for the first group of printing elements; The swing cam 9b is for the second group of printing elements; the swing cam 10 is a detection shield plate; 11 is a photoelectric detector 12 is an ink ribbon; 16 is a platen 14;

Claims (1)

[Claims] Groups of printing elements in which a plurality of printing elements are linearly arranged at a predetermined pitch are provided at two locations, and the groups of printing elements swing in the longitudinal direction while facing the printing medium at two locations, In a dot line printer connected by a swinging mechanism in which the swinging phases are opposite to each other, a slit-shaped detection shield plate is provided integrally with the first group of printing elements, and integrated with the second group of printing elements. A position detection device for a dot line printer, characterized in that a photoelectric detector is provided in the dot line printer.