JPH01103473A - Printer - Google Patents

Abstract

PURPOSE:To prevent a printed image from being inclined and contrive a longer useful life by providing at least two detecting means for detecting whether the leading end of a recording paper is fixed at a predetermined position relative to a platen. CONSTITUTION:Optical sensors 11, 12 are provided in correspondence with two notches 10a, 10b formed in a paper gripper 10. The gripper 10 presses a leading end part of a recording paper 1 fed onto a flat part 3a of 8 platen 3. Next, a stepping motor 5 rotates the platen 3 in the direction of an arrow A. At this moment, the sensors 11, 12 detect whether the paper is present, through the notches 10a, 10b of the gripper 10. When the paper 1 is mounted properly, the waveforms of outputs from the sensors 11, 12 are equal to each other. When the paper 1 is mounted in a skewed state, a difference is generated between the waveforms of the outputs from the sensors 11, 12. A controlling circuit 7, upon detecting the difference, indicates that the paper is mounted improperly, and stops the motor 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printer that performs recording by winding recording paper around a platen, and particularly to an improvement in fixing the recording paper.

[Prior Art] FIG. 4 shows a conventional printer disclosed in Japanese Utility Model Application Laid-Open No. 60-173353.

The leading edge of the recording paper 1 is fed to the flat surface 3a of the platen 3 by a paper feeding mechanism (not shown). The paper gripper 2 is
The leading end of the recording paper 1 is pressed against the flat surface 3a of the platen 3. Then, the step motor 5 rotates the platen 3 in the direction of arrow A. At this time, cutout 2 of paper gripper 2
The sensor 6 detects the presence or absence of paper via a. If the output signal of the sensor 6 is lower than the reference value, the control circuit 7 stops the step motor 5 and indicates that the paper is incorrectly installed.

When the recording paper 1 is installed in the normal position, the platen 3 continues to rotate, and the recording paper 1 is wound onto the platen 3. Thereafter, the recording head 4 is pushed up, and printing starts in response to a recording signal from the control circuit 7.

[Problems to be Solved by the Invention] Since the conventional printer is configured as described above, it has had the following problems.

First, even if the recording paper l is loaded at an angle, printing
When printing was performed, there were cases where the printing was performed while being tilted with respect to the recording paper 1.

Secondly, there was a problem in that the recording head 4 directly hit the platen 3 and the platen 3 was damaged.

An object of the present invention is to solve the above-mentioned problems and provide a printer that does not produce tilted prints and has a long lifespan.

C. Means for Solving Problem] The printer according to the present invention includes two or more detection means for detecting whether or not the leading edge of the recording paper is fixed at a predetermined position with respect to the platen.

[Operation] Since the printer according to the present invention is provided with at least two detection means, it is possible to detect the inclination of the recording paper.

[Embodiment] An embodiment of the present invention is shown in FIG. 1. A paper gripper 10 serving as a paper fixing means has two notches 10a,
b is provided. Optical sensors 11 and 12, which are detection means, are provided corresponding to the cutouts 10a and 10b.

The leading edge of the recording paper 1 is fed to the flat surface 3a of the platen 3 by a paper feeding mechanism (not shown). The paper gripper 10 presses the leading end of the recording paper 1 against the flat surface 3a of the platen 3. Then, the step motor 5 rotates the platen 3 in the direction of arrow A. At this time, sensors 11 and 12 detect the presence or absence of paper via the notch 10a and lob of the paper gripper IO.

As shown in FIG. 2(a), when the paper l is correctly loaded, the outputs of the sensors 11 and 12 are as shown in FIG. 2(a).
b), as shown in FIG. 2(c), that is, the output waveforms of both sensors 11 and 12 are equal. The printing range 1a in this case is not tilted with respect to the recording paper 1.

As shown in FIG. 2(b), when the paper l is loaded at an angle, the outputs of the sensors 11 and 12 are as shown in FIG. 3(b),
As shown in FIG. 3(C), there is a difference X between the output waveforms of both sensors 11 and 12. The control circuit 7 detects this, displays that the paper is improperly loaded, and stops the motor 5. The amount of Shyness X required to determine that the mounting is defective is determined by detection accuracy, motor speed, paper size, etc.

In this embodiment, the arrangement pitch of the sensors 11 and 12 is approximately matched to the width of the recording paper 1. Therefore, if a paper smaller than a predetermined paper is loaded, this can be detected. That is, direct printing onto the platen 3 can be prevented.

[Effects of the Invention] The printer according to the present invention includes two or more detection means. Therefore, it is possible to detect not only the presence or absence of recording paper but also the inclination of the recording paper.

Therefore, printing and printing can be performed without tilting, and printing and printing on the platen can be prevented, and damage to the platen can be prevented.

That is, according to this invention, printing and printing accuracy are high;
It is possible to provide a printer with a long lifespan.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a printer according to an embodiment of the present invention, FIG. 2(a) is a plan view showing when paper is normally loaded, FIG. 2(b) and FIG. 2(C). is shown in Figure 2 (a
) is a diagram showing the outputs of the sensors 11 and 12 in the case of (
a) is a plan view showing the case where the paper is loaded at an angle;
FIG. 3B and FIG. 3C are diagrams showing the outputs of the sensors 11 and 12 in the case of FIG. 3 (Paper 1), and FIG. 4 is a perspective view showing a conventional printer. 3 is a platen, 3a is a flat part, 10 is a paper gripper,
10a and 1Ob are notches, and 11 and 12 are sensors. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (3)

[Claims] (1) Equipped with a platen, paper fixing means for fixing the leading edge of the recording paper on the platen, and two or more detection means for detecting whether the leading edge of the recording paper is fixed at a predetermined position with respect to the platen. A printer featuring (2) The detection means includes two optical sensors that detect the presence or absence of paper through two notches provided in the fixing means. Printer mentioned in section. (3) A patent characterized in that the detection means includes a control circuit that compares the output waveforms from the two optical sensors and determines that the paper is fixed at a predetermined position if they are equal. The printer according to claim 2.