JPS60243504A - Mark detecting device - Google Patents

Abstract

PURPOSE:To omit adjustment for every product with effect of the dispersion of output signals, by comparing the output signal from a photosensor with the output signal at the previous time, and detecting the end part, marks and the like of paper based on the result of the comparison. CONSTITUTION:A photosensor 3 receives the reflected light or the transmitted light from paper 2. Memories 51 and 52 store the signals from the sensor 3 through an A/D converter 4. A comparing means 62 compares the signals, which are sequentially stored in the memory 51 and the memory 52. A juding means 63 judges the result of the comparison. In this constitution, the output signal is low before the paper 2 is put on a platen. When the tip part of the paper 2 is inserted in the light receiving region of the sensor 3, the reflected light is increased and remains constant. The output signals of the sensor 3 are sequentially stored and updated in the memories 51 and 52 after the A/D conversion. The means 62 compares the present data and the data at the previous time in the memories 51 and 52. The means 63 judges whether the result exceeds the specified value or not and also judges the polarity. Thus the tip part and the end part of the paper 2 are found. The output signals are sent to a paper feeding and driving device and a printing control circuit.

Description

Detailed Description of the Invention (Technical Field of the Invention) The present invention relates to the leading edge or trailing edge of paper used in printers, marks placed on paper to set the reference position for printing, etc. (these are collectively referred to as This invention relates to a mark detection device for detecting marks (referred to as marks).

(Prior Art) FIG. 4 is a diagram showing the configuration of an example of a conventional mark detection device. This device irradiates light from a light source 1 such as a light emitting diode onto a sheet of paper 2, and receives reflected light whose intensity changes depending on the presence or absence of the sheet of paper 2 and the presence of marks using a photosensor v3. Output signal eO from
By comparing the voltage En with a predetermined set voltage En by a comparator 4, the presence or absence (end) of the paper 2 and any marks attached to the paper are detected.

In the conventional device with such a configuration, the photo sensor v5
Since the magnitude of the output signal eO output from the comparator 4 varies greatly depending on the type of paper, the distance between the paper and the photo sensor, between products, etc., it is not possible to fix the value of the set voltage ER applied to the comparator 4. However, it is necessary to adjust the value to the optimum value for each paper type and each product, and this adjustment man-hour is a problem when mass production is performed.

(Objective of the present invention) The present invention was made in view of the above-mentioned problems in conventional devices.The purpose of the present invention is to avoid being affected by variations in the magnitude of the photosensor output signal, and therefore to make adjustments for each product. The present invention aims to realize mark detection snow making that does not require the use of mark detection.

(Configuration of the present invention) The configuration of the present invention that achieves the above object includes seven photosensors that receive reflected light or transmitted light from paper, a storage unit that stores signals from these seven photosensors, and a storage unit that stores signals from the photosensors. Comparing means for comparing the signal with a predetermined period of time previous sensor output signal stored in the storage means, and determining means for determining the comparison result of the comparing means, wherein the determining means is configured to detect the comparison result of the comparing means. It is characterized in that marks on the paper are detected by determining whether or not the value exceeds a predetermined value.

In these figures, 1 is a light source such as a light emitting diode, 2 is a printing paper sent by the platen 20, and 3 is a photosensor, which uses a diffuser reflection type, and detects light from the surface of the paper 2 or the platen 20. Receives reflected light. 4 is an A/D converter that converts the output signal eO from the photosensor 3 into a digital signal; 51.52 is a memory; 6
1 is a memory control means coupled to each memory 51, 52;
A digital signal from the A/D converter 4 is input, and the digital signal is written to each memory 51, 52, p1 is read out, and the data is stored. Reference numeral 62 denotes comparison calculation means for comparing υ and predetermined calculations between the data read from each memory 51 and 52, and reference numeral 63 means for determining the output of the comparison calculation means 62.

Here, the memory control means 61. The comparison calculation means 62 and the judgment means 63 are functional blocks, and these are realized by a microprocessor.

The operation of the apparatus configured in this way will be described below, taking the case of detecting the leading edge of a sheet as an example.

FIG. 3 shows changes in the output signal eO of the 7-point sensor 3 before and after the paper 2 is mounted on the platen 2. The horizontal axis (X-axis) represents the feeding step of the paper 2. There is.

From step SO to 810, when the paper 2 is not attached to the platen 20, the photosensor 3 is receiving reflected light from the surface of the platen 20, and it is assumed that the surface of the platen 20 is made of, for example, black rubber. If there is, there is little reflected light and the level of the output signal SO is as low as eL.

The paper 2 is attached to the platen 20, and the leading edge of the paper 2 is
When the light enters the light receiving area of the photosensor 3 (feeding steps si, Si+1, Si+2), the reflected light increases,
The level of the output signal eO increases from 8L to eM and eH, and is maintained at e□ after the feed step S1+3...Sn.

In FIG. 1, the A/D converter 4 operates at a predetermined sampling period (for example, a period corresponding to one step of paper feeding).
7 A/D conversion is performed on the output signal eO from the auto sensor 3. A/D converted output signal. The current data D1 corresponding to OK, and the previous data pDi corresponding to the output signal eo before the time Δ (for example, the time required for one step)
-1 is sequentially stored and updated in memories 51 and 52.

The comparison means 62 compares the current data D1 stored in the memory 51.52 with the previous data D1-1.

Here, if there is no change in the output signal eo of the photosensor 3, that is, if the leading edge of the paper 2 has not entered the light receiving area of the 7th center t3, or if the paper 2 is loaded and the paper is being fed. In this state, the current data D1 and the previous data D1-1 have approximately the same value, and the comparing means 6
The result of the comparison operation in step 2 is a value close to zero. When the output signal eOK of the photosensor 3 changes, that is, when the leading edge or trailing edge of the paper 2 enters the light receiving area of the photosensor 3, the current data D1 and the previous data D1-1 are The values are different, and the result of the comparison operation by the comparing means 62 is a predetermined value.

The determining means 63 receives the comparison result from the comparing means 62, determines whether the comparison result is greater than a predetermined value, and determines whether the polarity (DI) is Di-1.

Determine Di (equivalent to Di-1) and calculate 5Di) Di-:L
If Di (Di-1), it is the leading edge of the paper 2, and if it is Di-1, it outputs a signal that indicates the trailing edge of the paper 2. This output signal is applied to, for example, a paper feed drive circuit to control the paper feeding. It is applied to the print control circuit and is used to control printing.

Here, the point S where the output signal of the photo sensor +73 changes
Data D corresponding to eLleH in 1 and S1+2
Obtain L and DH, perform the following calculation, and find the point SO corresponding to DO, or alternatively, find the intermediate point S1,011 (
By calculating SO), the leading edge or trailing edge of the paper 2 can be determined more accurately without being affected by the size of the light spot irradiated onto the paper 2 C) Note that the above In the above description, the case where the leading edge or trailing edge of the paper 2 is detected is explained as an example, but various marks attached to the paper 2 can also be detected in the same way.

Further, although here, the photosensor is designed to receive the amount of reflected light, it may be configured to receive the amount of transmitted light.

(Effects of the Present Invention) As explained above, the present invention compares the output signal from the photosensor with the past output signal, and detects the edge of the paper or the mark based on the comparison result. According to the present invention, it is possible to realize a mark detection device that is not affected by variations in the magnitude of the sensor output signal and does not require adjustment for each product.

[Brief explanation of drawings]

FIG. 1 is a configuration block diagram showing an example of the apparatus according to the present invention, FIG. 2 is a perspective view of main parts showing a part of paper, FIG. 5 is a waveform diagram showing output signals of the photosensor, and FIG. 4 1 is a configuration block diagram showing an example of a conventional device. 1...Light source, 2*+-Paper, 3...Photo sensor,
4., A/D converter, 51.52... memory, 62
. . . comparison means, 63 . . . judgment means, 6 . . . microprocessor.

Claims (1)

[Claims] (1) A photosensor that receives reflected light or transmitted light from paper, a storage device that stores signals from the photosensor, and a photosensor that stores the signal from the photosensor and the storage device a predetermined time ago. Comparing means for comparing the output signal with an output signal, and determining means for determining the comparison result of the comparing means, and the determining means determines whether the comparison result of the comparing means is equal to or greater than a predetermined value and marks the paper. A mark detection device that features seven when detected.