JPH04340679A - Medium mark reading system - Google Patents

Abstract

PURPOSE:To obtain the stable medium mark reading system to stably set a gain and not to lower a medium mark reading rate. CONSTITUTION:In the medium mark reading system to read a mark attached to a medium according to the gain by setting the gain for certifying the white level of the medium, a medium edge is detected before setting the gain, a gain setting position is decided with the detected medium edge as a reference, the gain is set at the decided gain setting position and according to the gain, the mark on the medium is read.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medium mark reading method, and more particularly to a medium mark reading method suitable for preventing a decrease in the medium mark reading rate.

0002

2. Description of the Related Art In recent years, a technique has been widely used in which a mark such as a bar code is attached to a medium and the mark is read by a device to obtain various information. This type of mark is used, for example, in supermarkets to recognize product type, price, etc. with a register device, and in financial institutions such as banks to recognize passbook account information and page information, etc. in a passbook recording device. It is used for various purposes, such as for recognizing ID information of a form in a character reading device, or for recognizing format information of a print medium in a serial printer or the like.

[0003] An example of a medium mark reading device for reading marks such as bar codes attached to such a medium is disclosed in Japanese Patent Application Laid-Open No. 10290/1983. An example of this is shown in FIG. In this medium mark reading device, medium mark reading is performed as follows.

First, the gain of the programmable amplifier 52 and the reference voltage set by the reference voltage generator 55 are initialized by a command from the CPU 56. In this initial setting, the detector 51 detects the level (white level) of the unprinted part of the medium.
This is done so that the output of the comparator 54 changes when it is detected. When the output of the comparator 54 changes due to the level detection of the non-printed part of the mark, the reference voltage generator 55 outputs the reference voltage (1) to the comparator 54 according to a command from the CPU 56, while the output of the programmable amplifier 52 changes to the reference voltage (1). 1) The gain of the amplifier 52 is set so as to be as follows.

Next, according to a command from the CPU 56, the reference voltage generator 55 sets a reference voltage (2) larger than the reference voltage (1), and the output of the programmable amplifier 52 reaches the reference voltage (1).
The gain of the amplifier 52 is set so as to be between the reference voltage (1) and the reference voltage (2). Thereby, mark reading is executed by the functions of the detector 51 and the code detection device 53 in a state where the programmable amplifier output level for the mark-unprinted portion is made constant.

As described above, the medium mark reading device performs gain control in advance to determine the white level of the medium, and then reads the medium mark.

[0007]

[Problems to be Solved by the Invention] However, in the device having the above configuration, it is necessary to set the position where the gain setting is to be performed in advance. In extreme cases, the gain may be set outside the medium or on the medium mark, resulting in a decrease in the medium mark reading rate.

An object of the present invention is to solve these conventional problems and provide a stable medium mark reading method in which gain setting is performed stably and the medium mark reading rate does not decrease. .

[0009]

[Means for Solving the Problem] In order to achieve the above object, the medium mark reading method of the present invention sets a gain to determine the white level of the medium, and reads the mark attached to the medium using the gain. In the medium mark reading method, before the gain setting, a medium edge is detected, a gain setting position is determined based on the detected medium edge, a gain setting is performed based on the determined gain setting position, and the gain setting position is determined based on the detected medium edge. The feature is that the mark on the medium is read by the gain.

0010

[Operation] In the present invention, before the gain setting, a medium edge is detected, a gain setting position is determined based on the detected medium edge, and the gain setting is performed based on the determined gain setting position. , the mark on the medium is read by the gain. As a result, regardless of changes in the insertion position of the medium guide, the gain can be set stably, and there is no drop in mark reading rate.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 2 is a block diagram of a horizontal dot printer to which the present invention is applied. In dot printers that print marks such as barcodes on media based on instructions from a host device, after the mark is printed, the mark sensor reads it to determine the reflectance, and if the mark cannot be read, it is reprinted. This shows possible configurations.

In FIG. 2, reference numeral 2 denotes a medium guide for determining the insertion position of the medium, which is movable in the same direction as the space direction B, and whose position can be set arbitrarily by the operator. 3 is a medium on which a media mark has been printed, 4 is a medium transport path that leads the medium 3 to the reading section, and 5 is a medium transport path 4
The medium 3 is driven by a driving means (not shown) provided above.
This is a roller for conveying the medium. Reference numeral 6 indicates a dot impact type print head, and reference numeral 7 indicates a carriage on which the print head 6 is mounted.This carriage 7 is fitted onto a carriage shaft 8 and moves in the space direction B. Reference numeral 11 denotes a mark sensor for reading medium marks mounted on the carriage 7, and as the carriage 7 moves, the sensor 11 moves in the medium conveying direction A.
3, and reads the medium mark printed on the medium 3.

FIG. 3 is a diagram showing the relationship between the carriage position and the medium position when the medium 3 has been conveyed by the medium conveying roller 5 to a predetermined position for reading the medium mark. Here, for A, B, and C, the medium guide 2 is on the left, in the center, and
This indicates the position of the medium when it is set to the right, but in some cases it may be set to an intermediate position.

FIG. 4 is a diagram showing the printing position of the medium mark printed on the medium 3. As shown in FIG. The medium mark is printed in a direction perpendicular to the medium conveyance direction A, that is, in the same direction as the space direction B, as shown in FIG. Furthermore, since the medium mark has a variable length, the gain setting prior to reading the medium mark must be performed at a position a on the medium 3 at a position α from the medium edge. However, as shown in FIG. 3, depending on the set position of the medium guide 2, the gain setting position Aa
, Ba, and Ca (in FIG. 3) have different carriage positions. In both cases, the gain setting position is at a position α from the edge of the medium.

FIG. 1 is a diagram for explaining a medium mark reading method showing an embodiment of the present invention. This is shown in Figure 2
Horizontal dot printer and CP as a host device shown in
It shows a block configuration in which U are connected.

In FIG. 1, 7 is a carriage, 11 is a medium mark sensor, and 13 is a carriage 7 characteristic of the present invention.
16 is a carriage drive circuit that controls the drive of the carriage 7; 17 is a medium conveyance roller drive circuit that controls the drive of the medium conveyance roller 5; 18 is a control circuit for all of these circuits; This is a CPU as a host device. 19 is a medium mark reading circuit.

Next, the operation of this embodiment will be explained. First of all,
The CPU 18 issues a command to the medium conveyance roller drive circuit 17 to convey the medium to a predetermined position. Next, the CPU 18 issues a command to the carriage drive circuit 16 to drive the carriage 7.
is moved in the direction that the carriage position decreases, and
The state of the medium mark sensor 11 is monitored, and the carriage position detection circuit 13 reads the carriage position CP when the state of the medium mark sensor 11 changes from medium present to medium absent. That is, detect the media edge. Next, the CPU
Reference numeral 18 denotes a carriage 7 for the carriage drive circuit 16.
A command is issued to move the carriage from the carriage position CP to the position CP+α. After the carriage 7 completes moving to the carriage position CP+α, the CPU 18 issues a gain control command to the medium mark reading circuit 19. Thereafter, the CPU 18 issues a command to the carriage drive circuit 16 to move in a direction in which the carriage position increases, and at the same time issues a command to the medium mark reading circuit 19 to read the medium mark.

As described above, in this embodiment, the carriage position detection circuit detects the position at the time of reading the edge of the medium, and the gain setting position is determined based on this position, so it is difficult to determine the position of the medium guide 2. Even if it is set, gain control can be performed at a position α from the edge of the medium.

[0019]

[Effects of the Invention] As explained above, according to the present invention,
Prior to gain setting, the edge of the medium is detected and the gain setting position is determined based on it, so that gain setting can be performed stably and medium marks can be read stably.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining a medium mark reading method showing an embodiment of the present invention.

FIG. 2 is a configuration diagram of a horizontal dot printer to which the present invention is applied.

FIG. 3 is a diagram showing the relationship between the carriage position and the medium position after the medium is conveyed.

FIG. 4 is a diagram showing the printing position of a medium mark printed on a medium.

FIG. 5 is a configuration diagram of a conventional medium mark reading device. 2 Media guide 3 Medium 4 Media conveyance path 5 Media conveyance roller 6 Print head 7 Carriage 8 Carriage shaft 11 Media mark sensor 13 Carriage position detection circuit 16 Carriage drive circuit 17 Roller drive circuit for media conveyance 18 CPU 19 Media mark reading circuit

Claims (1)

[Claims] 1. In a medium mark reading method in which a gain is set to determine the white level of the medium and a mark attached to the medium is read using the gain, before the gain setting, a medium edge is detected, and a mark attached to the medium is read. A medium mark reading method characterized in that a gain setting position is determined based on a detected medium edge, a gain is set according to the determined gain setting position, and a mark on the medium is read using the gain.