JP2008016998A - Optical reader and its correction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform reading by compensating temperature change and temporal change and normally irradiating a medium to be read with a fixed amount of light. <P>SOLUTION: When a driving electric current corresponding to a driving signal DRV is given from a driver 21 to a light emitter 11 in a case where the medium 1 to be read does not exist, the light outputted from the light emitter 11 is radiated to a point B at the side of an upper carrier guide 3 after passing the point A of a reflective optical sensor 10. The light radiated to the point B is outputted from a point C through an optical passage 30, and radiated to a light receiver 12 from the point A. The detection signal DET of the light receiver 12 is converted into a digital signal DIG and given to a light emission control unit 23. When a correction control signal COR is given in this case, the light emission control unit 23 adjusts the driving signal DRV relative to the driver 21, so as to allow a digital signal DIG to be a prescribed value. When the correction control signal COR is stopped, the value of the driving signal DRV to be outputted from the light emission control part 23 is held as it is, and then, the medium 1 is read. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical reading apparatus that conveys a medium and optically reads the medium, and a correction method thereof.

JP-A-7-160924 Japanese Patent Laying-Open No. 2005-27030

  Patent Document 1 describes an optical sensor device that optically detects a paper sheet to be read in an optical reading apparatus that reads paper sheets such as banknotes and forms while transporting them. The optical sensor device includes a sealed case that is attached to the lower conveyance guide and incorporates a light emitting element and a light receiving element, and a prism that is attached to the upper conveyance guide.

  A plastic case that covers the light emitting element and the light receiving element is provided in the hermetic case, and a transmission part for outputting the light output from the light emitting element to the outside of the plastic case, and the light incident on the outside and the light receiving element Another transmissive part for irradiating is formed.

  On the other hand, the prism attached to the upper conveyance guide is formed in a size and shape so as to reflect the light emitted from the light emitting element of the sealed case and output from the transmissive part, and enter the other transmissive part of the sealed case. Has been.

  In this optical sensor device, if there is no paper sheet in the conveyance path, the light output from the light emitting element in the sealed case of the lower conveyance guide is returned to the light receiving element via the prism of the lower conveyance guide. . Further, when a paper sheet is present in the transport path, the light output from the light emitting element is blocked by the paper sheet, so that the light receiving element is not irradiated with light. Therefore, by checking the output signal of the light receiving element, it is possible to detect the presence or absence of paper sheets on the conveyance path. Since this optical sensor device houses a light emitting element and a light receiving element in a sealed case, it is supposed that dust, dust, paper dust, and the like can be prevented from adhering to the light emitting element and the light receiving element.

  In Patent Document 2, a lamp abnormality detection process is performed in which a document guide plate provided at a document reading position is read between documents sequentially conveyed by an automatic document feeder, and a lighting state of an exposure lamp is detected. A configured image reading apparatus is described. As a result, it is not necessary to provide a new white reference plate for detecting an abnormality in the exposure lamp or increase the amount of light at both ends of the exposure lamp, and a normal image reading operation using an automatic document feeder is executed. However, it is said that the lighting state of the exposure lamp can be detected.

  However, the devices described in Patent Documents 1 and 2 only detect the medium to be read and detect the abnormality of the light source, but do not adjust the light amount. For this reason, there has been a problem that variations in sensor output occur due to temperature changes and changes with time.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical reading apparatus that can compensate for temperature changes and changes with time, and always irradiate and read a medium to be read with a constant light amount, and a correction method therefor.

  The present invention includes a first transport path guide provided with a reflective optical sensor having a light emitting section and a light receiving section, and a second transport path guide disposed in parallel to face the first transport path guide. In the optical reading device that optically reads the surface of the medium by conveying the medium to be read in a certain direction, the light source of the reflective optical sensor is provided in the second conveyance path guide. An optical path that receives the output light and irradiates the light receiving unit of the reflective optical sensor and a detection signal output from the light receiving unit when a correction control signal is given to a predetermined value set in advance. The light emission control part which adjusts the intensity | strength of the light output from the said light emission part is provided.

  In the present invention, the reflection type optical sensor is provided in the first conveyance path guide, and the light emitting portion of the reflection type optical sensor is arranged on the second conveyance path guide arranged in parallel to face the first conveyance path guide. For example, before reading the medium, a detection signal output from the light receiving unit is set in advance according to the correction control signal. A light emission control unit for adjusting the intensity of light output from the light emitting unit is provided so as to have a predetermined value. Accordingly, there is an effect that the temperature change and the change with time are compensated, and the reading target medium can always be irradiated and read with a constant light amount.

  The above and other objects and novel features of the present invention will become more fully apparent when the following description of the preferred embodiment is read in conjunction with the accompanying drawings. However, the drawings are for explanation only, and do not limit the scope of the present invention.

FIGS. 1A and 1B are conceptual diagrams of an optical reading apparatus showing Embodiment 1 of the present invention.
As shown in FIG. 1A, the optical reading apparatus is parallel to a lower conveyance path guide 2 that conveys a medium 1 to be read, and a predetermined distance from the lower conveyance path guide 2. The upper conveyance path guide 3 is disposed in the upper side.

  A spot-type reflective optical sensor 10 is embedded in the lower conveyance path guide 2 at a position through which the reading target portion passes when the medium 1 is conveyed. The reflective optical sensor 10 detects a light emitting unit 11 such as a light emitting diode disposed so as to irradiate the point A on the surface of the reflective optical sensor 10 and the light reflected from the medium 1 at this point A. A light receiving portion 12 such as a photodiode.

  A driving current is supplied from the driving unit 21 to the light emitting unit 11. The detection signal DET of the light receiving unit 12 is supplied to a main control unit (not shown) and is also supplied to an analog / digital converter (A / D) 22 to be converted into a digital signal DIG. A light emission control unit 23 is connected to the output side of the analog / digital converter 22. The light emission control unit 23 has a function of adjusting the magnitude of the drive signal DRV for the drive unit 21 so that the digital signal becomes a predetermined value when the correction control signal COR is given from the main control unit. . In addition, the light emission control unit 23 holds the adjusted value of the drive signal DRV when the correction control signal COR is not given from the main control unit.

  On the other hand, the upper transport path guide 3 is a prism that guides the light at point B, which is irradiated with the light output from the light emitting unit 11 of the reflective optical sensor 10 and passed through the point A, to the point C facing the point A, etc. The light path 30 is embedded. The optical path 30 can be composed of, for example, a colorless and transparent glass or plastic prism having a width of about 3 mm, or an optical fiber.

  The reflective optical sensor 10 in FIG. 1A has a structure having one light emitting section 11 and one light receiving section 12, but as shown in FIG. 1B, two light emitting sections 11, 11a. Thus, it is possible to use the reflective optical sensor 10A configured to irradiate the point A with light from two directions. In this case, the optical path embedded in the upper conveyance path guide 3 may be the same optical path 30 as in FIG. 1A, but as shown in FIG. Using a light path 30A configured to guide the light at the point B irradiated with the light passing through A and the light at the point D irradiated with the light output from the light emitting unit 11a and passed through the point A to the point C Also good.

Next, the operation will be described. The following description is for FIG.
A correction control signal COR is given from the main control unit (not shown) to the light emission control unit 23 in the state where the medium 1 to be read does not exist in the conveyance path between the lower conveyance path guide 2 and the upper conveyance path guide 3.

  Accordingly, the drive signal DRV held in the light emission control unit 23 is given to the drive unit 21, and a drive current having a magnitude corresponding to the drive signal DRV is given from the drive unit 21 to the light emission unit 11. The light output from the light emitting unit 11 driven by the driving current passes through the gap between the lower conveyance guide 2 and the upper conveyance path guide 3 through the point A, and is irradiated to the point B on the upper conveyance guide 3 side. .

  The light irradiated to the point B on the upper conveyance path guide 3 side is output from the point C through the optical path 30. The light output from the point C passes through the gap between the upper conveyance path guide 3 and the lower conveyance path guide 2 and is irradiated from the point A to the light receiving unit 12 of the reflective optical sensor 10.

  The light receiving unit 12 outputs a detection signal DET according to the intensity of the irradiated light. The detection signal DET output from the light receiving unit 12 is given to the analog / digital converter 22 to be converted into a digital signal DIG and given to the light emission control unit 23. The light emission control unit 23 adjusts the drive signal DRV for the drive unit 21 so that the digital signal DIG has a predetermined value. That is, for example, when the amount of light received by the light receiving unit 12 is small and the value of the digital signal DIG is smaller than a predetermined value, the value of the driving signal DRV for the driving unit 21 is increased so that the digital signal DIG is less than the predetermined value. If it is larger, the value of the drive signal DRV is decreased. As a result, the digital signal DIG is adjusted to a predetermined value. Thereafter, when the correction control signal COR from the main control unit stops, the value of the drive signal DRV output from the light emission control unit 23 is held as it is.

  Next, when the medium 1 to be read is transported to the transport path, the light output from the light emitting unit 11 of the reflective optical sensor 10 is irradiated on the surface of the medium 1 passing through the point A. At this time, the intensity of the light output from the light emitting unit 11 corresponds to the value of the corrected drive signal DRV held and output by the light emission control unit 23. The light irradiated on the surface of the medium 1 is reflected by the surface of the medium 1, and the reflected light enters the light receiving unit 12. As a result, a detection signal DET corresponding to the intensity of the light incident on the light receiving unit 12 is output from the light receiving unit 12 and given to a main control unit (not shown), and reading processing is performed by the main control unit. In addition, since the light output from the light emission part 11 is blocked | interrupted with the medium 1, it is not irradiated to the optical path 30 by the side of the upper conveyance path guide 3. FIG.

  As described above, in the optical reading device of the first embodiment, when the medium 1 is not present, the light path that irradiates the light receiving unit 12 with the light output from the light emitting unit 11 of the reflective optical sensor 10 is folded. 30, an analog / digital converter 22 that controls the drive current of the light emitting unit 11 so that the detection signal DET of the light receiving unit 12 becomes a predetermined level, a light emission control unit 23, and a drive unit 21. Accordingly, there is an advantage that the temperature change and the change with time can be compensated and the reading target medium 1 can always be irradiated and read with a constant light amount.

FIG. 2 is a conceptual diagram of an optical reading apparatus showing Embodiment 2 of the present invention.
In the second embodiment, instead of the spot-type reflective optical sensor 10 provided on the lower transport path guide 2 of the first embodiment, the reflective optical sensor arranged at right angles to the transport direction of the medium to be read. A line sensor 40A is used. The reflective optical line sensor 40A includes a plurality of light receiving elements 42 arranged in a line and a plurality of light emitting elements 41 and 41a for irradiating light to the reading line in a line. The light emitting elements 41 and 41a and the light receiving element 42 do not have to be associated with 1: 1.

  On the other hand, the upper conveyance path guide 3 is provided with a plurality of optical paths 30A similar to those of the first embodiment along the reflective optical line sensor 40A. Each optical path 30A divides the reading range of the reflective optical line sensor 40 arranged perpendicular to the conveyance direction of the medium 1 into a plurality of areas, and guides the light output from the light emitting elements 41 and 41a in each area. The corresponding light receiving element 42 is irradiated. Here, although the corresponding light receiving element 42 may be one, a plurality of light receiving elements 42 may be used, and the total or average of the detection signals output from each light receiving element may be used as the detection signal DET for adjusting the light amount. good.

  Although not shown in FIG. 2, the analog / digital converter 22, the light emission control unit 23, and the drive unit 21 similar to those in FIG. 1 are connected to the output side of the light receiving element 42 corresponding to each light path 30A. The drive unit 2 can supply drive currents to the light emitting elements 41 and 41a in the corresponding region.

  In this optical reader, the reading range of the reflective optical line sensor 40A provided at a right angle to the medium transport direction is divided into a plurality of areas, and the light output from the light emitting elements 41 and 41a is divided for each area. The drive currents of the light emitting elements 41 and 41a are adjusted so that the intensity is detected by the corresponding light receiving element 42 and the intensity of the received light becomes a predetermined value. Other operations are the same as those in the first embodiment.

  As described above, since the optical reading device of the second embodiment is provided with a plurality of light paths 30A corresponding to the reflective optical line sensor 40A, the light emitting element 41 of each region including each light path 30A is provided. The amount of light can be adjusted, and the same advantages as in the first embodiment can be obtained.

In addition, this invention is not limited to the said Example, A various deformation | transformation is possible. Examples of this modification include the following.
(A) FIG. 3 is a conceptual diagram of an optical reading device showing a first modification of the present invention. The optical reader of Example 2 in FIG. 2 uses the optical path 30A configured to output the light received at two places collectively from one place as in FIG. 1B, but in FIG. As in FIG. 1A, the light path 30 configured to output light received at one place from one place is arranged in a zigzag shape.

(B) The reflective optical line sensor 40A in FIG. 2 irradiates the medium to be read with the light emitting elements 41 and 41a arranged in two rows, but uses the light emitting elements arranged in one row. You can also. In that case, an optical path 30 as shown in FIG. 1A or FIG. 3 is used.

(C) In the optical readers shown in FIGS. 2 and 3, the colorless and transparent optical path is used, so that the light quantity for each wavelength cannot be adjusted. However, by providing a color filter in the optical path, the light quantity for the light sources having a plurality of wavelengths is provided. Adjustment is possible.

(D) FIG. 4 is a cross-sectional view of an optical path showing a second modification of the present invention. The light path 30B is arranged such that the light irradiation surfaces B and D are perpendicular to the incident light, and the surfaces of the light irradiation surfaces B and D are formed in a convex lens shape. Thereby, the reflective component of incident light can be reduced and light condensing property can be improved. Furthermore, a surface C from which light that has passed through the light path 30B is output is formed in a convex lens shape. Thereby, the output light can be efficiently applied to the light receiving unit 12.

(E) FIG. 5 is an explanatory diagram of light amount control showing a third modification of the present invention. In the first embodiment, the light emission control unit 23 adjusts the drive signal DRV for the drive unit 21 so that the digital signal DIG output from the analog / digital converter 22 has a predetermined value. A certain permissible range may be provided around the center. In this case, as shown in FIG. 5, when the digital signal DIG falls below the lower limit value LLM, the drive signal DRV is increased and controlled to reach the target value TGT. Further, when the digital signal DIG exceeds the upper limit value ULM, the drive signal DRV is decreased and controlled so as to become the target value TGT. In these cases, as long as the digital signal DIG is between the lower limit value LLM and the upper limit value ULM, the drive signal DRV is not controlled. As a result, frequent light quantity control around the target value TGT is avoided, and the processing efficiency can be improved.

(F) The detection signal DET of the light receiving unit 12 and the light receiving element 42 is converted into a digital signal DIG and the light quantity of the light emitting unit 11 and the light emitting element 41 is controlled so as to have a predetermined value. Alternatively, the comparison may be made in the state of an analog signal.

It is a conceptual diagram of the optical reader which shows Example 1 of this invention. It is a conceptual diagram of the optical reader which shows Example 2 of this invention. It is a conceptual diagram of the optical reader which shows the modification 1 of this invention. It is sectional drawing of the optical path which shows the modification 2 of this invention. It is explanatory drawing of the light quantity control which shows the modification 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Medium 2 Lower conveyance path guide 3 Upper conveyance path guide 10 Reflection type optical sensor 11, 11a Light emission part 12 Light reception part 21 Drive part 22 Analog / digital converter 23 Light emission control part 30, 30A Light path 40A Reflection type optical line sensor 41, 41a Light emitting element 42 Light receiving element

Claims (6)

Between a first transport path guide provided with a reflective optical sensor having a light emitting section and a light receiving section, and a second transport path guide arranged in parallel to face the first transport path guide, In an optical reader that optically reads the surface of the medium by conveying the medium to be read in a certain direction,
An optical path that is provided in the second transport path guide and receives light output from the light emitting unit of the reflective optical sensor and irradiates the light receiving unit of the reflective optical sensor;
A light emission control unit that adjusts the intensity of light output from the light emitting unit so that a detection signal output from the light receiving unit has a preset predetermined value when a correction control signal is given;
An optical reading device comprising:   The reflective optical sensor includes a plurality of light emitting units that irradiate the same portion of the medium to be read, and the light path receives light output from the plurality of light emitting units and receives light from the reflective optical sensor. The optical reader according to claim 1, wherein the optical reader is configured to irradiate a portion. A first transport path guide provided with a plurality of light emitting elements arranged in a line and a reflective optical sensor having a plurality of light receiving elements arranged in a line corresponding to the light emitting elements, orthogonal to the transport direction And a second transport path guide disposed in parallel to face the first transport path guide, and an optical reading device that optically reads the surface of the medium by transporting the medium to be read In
Provided in the second transport path guide, the reading range of the reflective optical sensor is divided into a plurality of areas, and the light output from the light emitting element of the reflective optical sensor is received for each of the divided areas; A plurality of light paths for irradiating the corresponding light receiving elements of the reflective optical sensor;
When the correction control signal is given, the plurality of light emitting elements are set such that detection signals output from the plurality of light receiving elements irradiated with light through the light path have predetermined values set in advance. A light emission control unit for adjusting the intensity of light output from the element;
An optical reading device comprising:   The reflective optical sensor includes a light emitting element that outputs light of a plurality of wavelengths, and a filter that matches each wavelength of the plurality of wavelengths is provided in the plurality of light paths. 3. The optical reading device according to 3. Between a first transport path guide provided with a reflective optical sensor having a light emitting section and a light receiving section, and a second transport path guide arranged in parallel to face the first transport path guide, A correction method for an optical reader that optically reads the surface of a medium by conveying the medium to be read in a certain direction,
When the medium to be read does not exist, an optical path for receiving light output from the light emitting part of the reflective optical sensor and irradiating the light receiving part of the reflective optical sensor is provided in the second transport path guide. ,
Adjusting the intensity of the light output from the light emitting unit so that the detection signal output from the light receiving unit has a predetermined value set in advance;
A correction method for an optical reading device. A first transport path guide provided with a plurality of light emitting elements arranged in a line and a reflective optical sensor having a plurality of light receiving elements arranged in a line corresponding to the light emitting elements, orthogonal to the transport direction And a second transport path guide disposed in parallel to face the first transport path guide, and an optical reading device that optically reads the surface of the medium by transporting the medium to be read The correction method of
The reflective optical sensor reading range is divided into a plurality of areas, and when there is no medium to be read, the light output from the light emitting element of the reflective optical sensor is received for each of the divided areas. A plurality of light paths for irradiating corresponding light receiving elements of the reflective optical sensor are provided in the second transport path guide,
The intensity of light output from the plurality of light emitting elements is adjusted so that detection signals output from the plurality of light receiving elements irradiated with light through the optical path have predetermined values set in advance. That
A correction method for an optical reading device.

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