JPS60257279A - Paper detector for printer - Google Patents

Abstract

PURPOSE:To detect the presence or absence of a paper, the wide of the paper and the inclination of the paper, by providing a paper-detecting means on a surface of a carriage moved in parallel to the platen which surface is opposed to the platen. CONSTITUTION:With the paper 3 fed to a printing-starting position, the presence or absence thereof is detected by some of reflection-type photo-sensors 12-14. Next, the carriage 8 is moved in the direction of an arrow F4 to detect the right end of the paper 3 by the sensor 12, and then the carriage 8 is moved at a fixed velocity in the direction of an arrow F3 to detect the left end of the paper. The width of the paper is obtained by dividing the velocity by the period of time over which an output signal from the sensor is ''1''. Then, the paper 3 is returned in the direction of an arrow F1 until the moment immediately before the output signal from the sensor 12 becomes ''0'', and when an output signal from the sensor 13 is ''0'' and that from the sensor 14 is ''1'', it is detected that the angle of inclination of the paper 3 is not larger than a maximum allowable angle of inclination. When both of the output signals are ''1'', it is detected that the angle of inclination is not smaller than the maximum allowable angle of inclination and the paper 3 is in a left-side upward condition, and when both of the output signals are ''0'', it is detected that the paper 3 is in a right-side upward condition.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a position detection device for a printer.

[Prior art]

Printers, which are one of the output devices of computers, come in various types depending on the purpose of use, from low-speed machines with slow printing speeds to high-speed machines with continuous printing speeds.

Among these printers, low-speed to medium-speed models print one line on paper fed between the print head and platen while moving the carriage on which the print head is mounted parallel to the platen. The paper is fed every time a minute's printing is completed.

Conventional paper detecting devices for such printers have only detected the presence or absence of paper by disposing position detection means such as photosensors or microswitches on the paper travel path.

For this reason, conventional printers detect when paper is set that is narrower than the print width that the printer should print, or when paper is set at an angle to the carriage that moves parallel, that is, the print head. The problem was that I couldn't do it.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a paper detection device for a printer that detects not only the presence or absence of paper, but also the width of the paper and whether or not the paper is set diagonally.

[Structure of the invention]

Therefore, in the present invention, a paper detection means is provided on the surface facing the platen of a carriage that moves parallel to the platen, and the width of the paper is detected by moving the carriage.
Further, by providing a plurality of paper detecting means, the inclination of the paper is detected.

〔Example〕

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

FIG. 1 is a perspective view of a printer equipped with a printer paper detection device according to the present invention.

In FIG. 1, a bath-shaped platen 1 having an appropriate diameter is driven to rotate according to the rotation of a step motor 2. ) 3 is sandwiched between feed rollers 4 and 5 that rotate with the rotation of the grating 1, and is sent in the direction of arrow F2 in close contact with the graten 1.

In addition, it is installed near platen 1, and
a carriage 8 on which a printing head 6 and an ink-clean cassette 7 are mounted for composing and printing characters by turns;
A guide shaft 9 arranged parallel to the rotation axis lt of the platen 1 is inserted into the platen 1 side, and has a cam groove arranged parallel to the rotation axis lt of the platen 1 on the opposite side. 10 is fitted and inserted, and the drive shaft 10 rotates in accordance with the rotational operation of the step motor 11, thereby moving in parallel along the platen 1 in the direction of arrow F3 or the direction of arrow F4.

The printer configured as described above prints one line on the paper 3 while moving the carriage 8 in the direction of the arrow F3, and each time printing for one line is completed, the paper 3 is moved in the direction of the arrow F2 by the linefeed pitch. It is supposed to be sent to

The moving speed of the carriage 8 varies depending on the printing content, but is constant when moving without printing.

On the surface of the carriage 8 that corresponds to the platen l,
A reflective photosensor 12 in which a light emitting element and a light receiving element are integrally formed is disposed on the right side as a sheet detection means, and reflective photosensors 13 and 14 of the same type as the reflective type 7 sensor 12 are disposed on the left side.

Next, FIG. 2 is a diagram of the carriage 8 shown in FIG. 1 viewed from the direction of arrow F1.

The reflective photosensor 12 is arranged above the moving direction axis 8 of the carriage 8, and the reflective photosensors 13 and 14 are arranged at symmetrical positions with respect to the moving direction axis 8tllC.

This moving direction axis 8t and the reflective photosensor 12.13
The angle θ formed by the straight line connecting them and the moving direction axis 11J, st
The angle θ formed by the straight line connecting the reflective photosensor 12. Even if there are multiple inclinations, printing is possible if the inclination is less than the maximum allowable inclination.

In addition, the reflective photosensors 12 to 14 in the above-mentioned positional relationship are located at the points where the straight line connecting each sensor and the rotation axis iA of the platen 1 (see FIG. 1) intersects the surface of the platen 1 that is in close contact with the paper 3. , outputs a signal @l# when there is paper 3, and outputs a signal "0" when there is no paper 3, thereby detecting the presence or absence of paper 3 at the intersection point.

The position of the paper 3 shown in FIG. 2 is the printing position of the first character in the first row of the paper 3, that is, the printing start position.

Next, the operation of the paper detecting device of the printer according to the present invention will be explained with reference to the front view of the carriage 8 shown in FIG.

First, when the paper 3 is sent to the printing start position, the presence or absence of the paper 3 is detected based on the output of one of the reflective photosensors 12 to 14, for example, the sensor 12. That is, for the paper 3, the output signal of the reflective photosensor 12 is '1'.
When it is #, it is at least near the print start position and 0''
When , it can be detected that the object is not near the position (see FIG. 3 (sL)).

Next, when the paper 3 is near the printing start position, the carriage 8 is first moved in the direction of arrow F4, the right end of the paper 3 is detected by the reflective photosensor 12, and then the carriage 8 is moved at a constant speed in the direction of arrow F4. The sensor 12 detects the left end of the sheet 3, and the output signal of the sensor 12 after the carriage 8 starts moving in the direction of arrow F3 is determined by the moving speed of the carriage 8 at this time. The width of the paper 3 is detected by dividing by the time #.When detecting the width of the paper, the positions of both left and right ends of the paper 3 are also detected.

Next, when the paper 3 is near the print start position, the paper 3 is returned in the direction of arrow F1 until just before the output signal of the reflective photosensor 12 becomes @0# (see FIG. 3(b)). At this time, if the output signal of the reflective type 7 photo sensor 13 is 10# and the output signal of the photosensor 14 is "1#", the paper 3
is detected to be less than the maximum allowable inclination (see Fig. 3(b)), and if the output signals of the photosensors 13 and 14 are @1', the paper 3 is found to have an inclination greater than or equal to the maximum allowable inclination υ and the upper left is detected to be 9 (see Figure 3(c)).
, if the output signals of the photosensors 13 and 14 are @0', it is detected that the paper 3 has an inclination greater than the maximum allowable inclination and is upwardly oriented (see FIG. 3(d)).

Note that the paper 3 is not limited to single-sheet paper, and continuous form paper having sprocket holes may be used. In this case, the printer feeds the paper by hooking the sprocket hole to the stripe rocket pin.

In addition, in addition to the method of printing by configuring characters with do, tomato, and cross patterns as in this embodiment, any printer in which a carriage equipped with a print head moves in parallel along a platen to print can also be used as an inkjet printer. A printing method such as a printing method or a thermal recording method may be used.

Furthermore, the reflective photosensor disposed on the carriage is not limited to the positional relationship shown in the above embodiment, but can be arranged in any way as long as it can detect the presence or absence of paper, the width of the paper, and the tilt of the paper. Good too.

[Effects of the Invention] As explained above, according to the present invention, a plurality of position detection means are provided on the surface facing the platen of the carriage that moves parallel to the platen, and the presence/absence of paper and the width of the paper can be detected. , the inclination of the paper can be detected.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a printer equipped with a paper detecting device for a printer according to the present invention, FIG. 2 is a front view of the carriage shown in FIG. 1, and FIG. 3 is an operation of the paper detecting device for a printer according to the present invention. FIG. 1...Platen, 2.11...Step motor, 3
...(single sheet) paper, 4, 5...feeding roller, 6...
・Print head, 7... Ink ribbon cassette, 8...
- Carriage, 9... Guide shaft, 10... Drive shaft, 12 to 14... Reflective photosensor. Figure 3 (0)

Claims (3)

[Claims] (1) The platen, the carriage on which the print head is mounted, the carriage drive device that moves the carriage parallel to the platen, and the paper feeding device that supplies paper between the platen and the print head are reduced. In the paper detection device of the printer, a paper detection means is provided on the surface of the carriage facing the platen, and the presence or absence of paper, the width of the paper, and the positions of both left and right ends of the paper are detected based on the output of the paper detection means. , and at least one of the inclination of the paper. (2) The width of the paper and the positions of both left and right ends of the paper are detected based on a signal output from the paper detection means when the carriage moves in parallel. Printer paper detection device. (3) The paper detecting means is comprised of a plurality of means arranged according to a predetermined spatial arrangement, and the detection of the inclination of the paper is performed in accordance with the output mode of the plurality of means. A paper detection device for a printer according to item (1).