JPS60179282A - Printer - Google Patents

Abstract

PURPOSE:To check possible skewing preventing damage to a platen by arranging more than one sensor at the position close to the exhaust side in such a manner as to be symmetrical with respect to the center axis of a paper in the going direction thereof to secure the detection of no paper. CONSTITUTION:Two sensors 13a and 13b are set somewhere close to the exhaust side from the printing position A. As the tip of a paper 2 advances into an insertion slot 6 from a paper guide plate 5, a sensor 9 detects the advance of the paper 2 and outputs the detection signal to a control section to start rotating the platen 3 in the direction of discharging the paper. As the tip of the paper 2 passes a pair of sensors 13a and 13b simultaneously, based on the detection signal, the paper is wound back while a signal is outputted to a printing section to enable the printing at the printing section. When there is a different in the time at which the paper passes the sensor 13a and 13b, the control section detects the time difference between the detection signals and sets the printing section to disable the printing to show it on a display when the difference is larger than the specified value.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Background) The present invention relates to a printing device that can properly detect blank paper to prevent damage to a platen due to blank printing and prevent paper skew.

(Prior art) A printing device equipped with a conventional paper autoloading mechanism (
For example, as an electric typewriter (for example, an electric typewriter, etc.),
(a) There are things shown in (b). This printing device 1 has paper 2
There is an automatic printing section 4 for automatically transporting and placing the image to the printing position on the platen 3. OI Loading 8 [(4) A paper guide plate 5 that guides the paper to the paper insertion slot 6, a paper guide 7 that guides the paper by a guide roller 8, a platen 3 that is rotationally driven by a motor, and a passage of the paper. Consists of Senna 9 that detects 71
Reference numeral 10 indicates a print head, and the tip position of the print head 10 is a print position A. The sensor 9 is placed in front of the printing position 1, for example near the illustrated insertion slot 6, or the paper guide 7
The control unit detects whether the leading edge of the paper 2 has passed and outputs a detection signal to the control unit. The control section outputs a control signal to the printing section based on the signal, and controls the printing section so that it does not become ready for printing when the paper 2 has not entered the insertion slot 6. Reference numeral 11 indicates a cover, and 12 indicates a paper holder.

In the second configuration, when the leading edge of the paper 2 enters from the insertion opening 6 and passes the sensor 9, the sensor detects this and inputs a sensor signal to the control unit.

Based on the sensor signal, the control section outputs a drive start signal to the motor to rotate the platen 3 by a predetermined angle in the forward direction indicated by the arrow. The paper 2 is guided by a paper guide 7 and transported while being pressed between the platen 3 and the roller 8. The amount of rotation of the platen 3 is set in advance so that the platen 3 stops when the leading edge of the paper passes a predetermined distance from the printing position. Further, the stop position of the leading edge of the two sheets can be finely adjusted by manually operating the knob 3a of the platen.

However, in conventional printing devices.

The sensor 9 is near the insertion slot 6 or the paper guide
5 Even if the advance of the paper stops after passing the sensor and before reaching the print position A due to a paper jam or other cause, the platen 3 rotates by a predetermined angle and becomes ready for printing. Therefore, the print head 10
When the printer starts printing, there is a risk of damaging the platen 3 due to blank printing. Further, since the sensor 9 detects the passage of the paper regardless of its orientation and sets the paper in a printable state, there is a risk that the paper may be printed in a skewed state.

(Object and structure of the invention) The present invention has been developed in view of the above.

In order to effectively detect blank paper and prevent damage to the platen, as well as to prevent the occurrence of skew, two or more sensors are installed at positions closer to the ejection side than the printing position and symmetrical to the central axis in the paper traveling direction. The present invention provides a printing device located at

(Example) A printing device according to the present invention will be explained below.

Figures 2(a) and 2(b) show an embodiment of the printing device of the present invention, and the same parts as in Figures 1(a) and (b) are designated by the same symbols 1
I will omit the duplicate explanation.

Two sensors 13a and 13b are installed on the discharge side from the printing position A (sensor 9 may be provided in the same way as in FIGS. 1(a) and 1(b)). The sensors 13a and 13b are arranged axially symmetrically on the cover 11 of the paper outlet 14 on a straight line orthogonal to the paper traveling direction. a pair of sensors 13a,
13b is preferably an optical sensor or a touch-sensitive sensor.

In the above configuration, the paper guide plate 5 is connected to the insertion slot 6.
When the product for sale 1 in L2 enters, the sensor 9 detects the entry of the paper 2 and outputs a detection signal to the control section (not shown), and based on the detection signal, the control section drives the drive motor of the platen 3. A start signal is output to start rotating the platen 3 in the paper ejection direction. The paper 2 is transferred in the extraction direction by the rotation of the platen 30, and the leading edge of the paper 2 is detected by a pair of sensors 13.
a, 13b at the same time, each sensor 13a, ]3
b simultaneously outputs a detection signal that detects the passage of paper to the control section, and based on the detection signal, the control section outputs a reversal drive signal to the motor to invert the platen 3 by a predetermined angle and rewind the paper at the same time. Outputs a signal to the printing section to enable the printing section. The paper 20 rewind meter is set so that the paper ejection position is at printing position A after rewinding. Further, the launch position 81K)QN is performed by manually turning the knob 3a. If there is a difference in the time at which the leading edge of the paper 2 passes through the pair of sensors 13a and 13b, that is.

When the paper 2 passes in a skewed state, each signal from each sensor 13a, 13b detecting the passage of the paper is inputted to the control unit with a time lag. Controlfffl
The first part detects the time lag of each detection signal from each sensor 13a, 13b, and if this lag is larger than a predetermined value, the printing part is placed in a non-printable state. The occurrence of skew is indicated by a display unit such as a skew indicator lamp.

The operator is instructed to reinsert the sheet or correct the posture of the sheet. Therefore, printing on skewed paper is prevented.

(Effects of the Invention) As explained above, according to the printing device of the present invention, two or more sensors are arranged symmetrically with respect to the central axis in the paper traveling direction, at positions closer to the ejection side than the printing position. In addition to ensuring detection and preventing damage to the platen,
It is possible to prevent the occurrence of skew.

[Brief explanation of the drawing]

Figures 1 (A) and (B) are an overall diagram and a partial configuration explanatory diagram of a conventional printing device, and Figures 2 (A) and (B) are partial configurations of an embodiment of the printing device of the present invention. Explanatory diagram. FIG. 3 is a flowchart 1 of the control operation of the present invention. Explanation of symbols ■...Printing device 2...Paper 3...Platen 3a...Knob 4...Auto loading section 5...Paper guide plate 6...Paper insertion lower...Paper guide 8...Guide roller 9...Senna 10...Print head 11...Cover I2...Paper presser 13.
... Senna 14 ... Exit patent applicant Fuji Xerox Co., Ltd. Agent Patent attorney Nobuyuki Matsuhara Agent Patent attorney Seiji Muraki Agent Patent attorney Taira 1) Tadao Figure 1 Figure 2 (Ino (0) ] Figure 3 [・ ■ν

Claims (1)

[Scope of Claim] A printing device that uses a print head to print at a predetermined print position on a sheet of paper spaced seven times on a platen. two or more paper detection sensors disposed symmetrically about a central axis in a paper traveling direction on the paper discharge side of the printing position; The paper skew is determined based on the detection timing difference when the paper detection sensor detects the leading edge of the paper, and control is performed to set the paper to a printable state when the paper is retreated by a predetermined distance 11 after detecting the leading edge of the paper. A printing device characterized by comprising a section.