Abstract:
A scanner guide slides along a guide rail aligned with a scanning path of the scanner. A positioner with projections or holes on the guide rail cooperates with holes or projections in the guide to identify a position of the scanner within bounds equal to or less than a maximum scanning path. The scanner is swingable between a scanning position overlying a bar code and an upright non-use position displaced from the bar code scanning surface. A bar code of extended length can be precisely verified as well as a shorter bar code by the bar code reader.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention generally relates to a bar code verifier for verifying whether a bar code symbol printed on a label or on the surface of an article is within a standard range or not and, more particularly, to a bar code verifier which can be applied to bar codes relatively longer than a field of effective view of a scanner of the apparatus. 
     2. Background Art 
     Referring first to FIG. 6, a bar code symbol designated as is generally comprised of a series of bars and spaces, and a relative size (i.e. length) L thereof may be from 20 mm to 193 mm as is in JIS X 502. Referring to FIG. 7, a prior art optical scanner 90 capable of reading various sizes of bar codes is composed of a light source 91, a sensor element 92, and a lens 93. 
     In the scanning systems of the prior art, the scanner 90 also includes a slit 94, and as this slit moves along the longitudinal direction of the bar code size L with constant speed, the sensor element 92 receives binary signals wherein bars 30a (black module) are represented by low level signals and the spaces 30b between the bars (white module) are high level signals. 
     Each binary signal is kept at a respective level according to respective width of the bars 30a and spaces 30b. The optical scanner will therefore scan the bar code pattern and generates binary signals representing the bars and spaces for transmitting to an appropriate memory device so as to determine the character represented by the bar code pattern regardless of the size L of bar codes 30. 
     In the conventional bar code scanner described above, when the bar code scanner 90 is used as an inputting device for a bar code verifier to verify accuracy of the bar code 30, the unsteady or meandering scanning causes a reading error, e.g., in widths of the bar 30a and space 30b. 
     Thus, it is desirable to provide such a static scanner as an inputting device of a bar code verifier where a static image of the bar codes 30 could be stored in an image sensor, e.g., CCD, and then read out for verifying accuracy of the bar code 30. However, if such a scanner is made so that a scanner enables to read a relatively long bar code 30 in size of, e.g., 193 mm, the scanner gets large in size and it is difficult to handle and such a scanner make an erroneous reading of a relatively shorter bar code as in sizes of 20 mm. 
     In addition, if such a verification is carried out by providing scanners suitable to some types of bar codes having different sizes, it is necessary to provide three or four different sized scanners. In this case, although verifying accuracy may be increased, handling the scanners, which is e.g. exchanging or correcting the scanners, is complicated. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide a novel and useful bar code reading device for verifying accuracy of a bar code in which the disadvantages of the aforementioned prior art are eliminated. Another object of the present invention is to provide a bar code reading device enabling reading of a longer bar code split by a field of effective view thereof that has high accuracy. Yet another object of the present invention is to provide a reading error free bar code reading device which has high reliability. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a bar code reading device of a bar code verifier adapted to verify accuracy of a longer bar code in a first embodiment of the present invention; 
     FIG. 2 shows a schematic side elevational view looking in the direction of arrows 2--2 in FIG. 1; 
     FIG. 3 is a perspective view showing a second embodiment of the present invention; 
     FIG. 4 shows a schematic side elevational view looking in the direction of arrows 4-4 in FIG. 3; 
     FIG. 5 illustrates a third embodiment of the present invention; 
     FIG. 6 depicts an illustrative bar code symbol to be verified; and 
     FIG. 7 is a schematic side elevational view of a conventional bar code scanner. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A first embodiment of the present invention will be described at first with reference to FIGS. 1 and 2. Referring to FIG. 1, there is illustrated a bar code scanner 1 designated as numeral 1 (hereinafter simply called as the scanner 1) for being applied to a bar code verifier according to the present invention. In a housing 2 of the scanner 1, there is provided a light source 3 such as an LED, a lens 4 and an image sensor element 5 such as a CCD on which a static image of a bar code 30 reaches through a lens 4 in order to precisely verify accuracy of a bar code 30. 
     It is not required that the size Δ of a reading window 2a of the housing 2 through which the shortest bar code 30 in length L can be accurately read along a scanning path is a length of 65 mm in this embodiment but the length, i.e., the minimum scanning length can be a length of 50 mm. 
     The housing 2 of the scanner 1 includes a longitudinal groove as a guide 6 to slide along a scanning path at the bottom thereof. Housing 2 further includes a viewing window 2b for verifying that a bar code is properly positioned in the reading window 2a. 
     Associated with the guide 6, there is provided a guide rail 10 fitting in the groove without shaking on which the scanner 1 is able to smoothly slide. 
     On the surface of the guide rail 10, a plurality of positioning holes 11 at spaces P equal to or less than the size D of the reading window that is the maximum scanning path. In addition, on the guide of the housing 2 there is provided a projection 7 fitted into the positioning hole 11. 
     When the space P between the positioning holes 11 is determined for the bar code 30 having the maximum length L, the size D of the reading window of the scanner extends across and slightly past the bar code without leaving out gaps. For example, if the bar code 30 is 193 mm in length and the size D of the reading window of the housing 2 is 50 mm, it is allowed for space P to be either 50 mm apart or 48.25 mm apart when overlapping reading is carried out. 
     According to the above construction of the present invention, it is possible to read a bar code longer than the size of the reading window of the scanner without missing any portion of the bar code by sequentially moving and setting the scanner 1 along the guide rail 10 on the position hole 11 and partially reading the longer bar code. In addition, it is possible to longitudinally slide the scanner 1 along a guide rail 10, i.e., the direction of a bar code length L. Further, the bar code 30 divided by reading is concatenated in sequence and decoded as a single code by an arithmetic circuit. 
     In the second embodiment of the present invention with reference to FIGS. 3 and 4, while the scanner 1 can be removable from the associated guide rail 10 in the first embodiment, in this embodiment it is possible to provide that a slider 21 sliding freely in a groove is integrated with a guide rail 20, moreover the slider 21 is integrated with a scanner 1 by a hinge 22 on which the scanner 1 swings between horizontal and a vertical position. 
     Furthermore, click stops 23 having the same spacing as that in the first embodiment reside between the guide rail 20 and the slider 21. The guide rail 20 comprises a fixing portion 24 thereof with an alignment window 24a corresponding to the reading window 1a of the scanner 1 so as to enable adjustment of a coordinate of the scanner in an upright position, and to prevent the scanner from falling down so as to stabilize in operation. The fixing portion 24 is positioned so that the bar code 30 (see FIGS. 1 and 2) can be viewed through the alignment window 24a. The scanner 1 is then swung downwardly to place the scanning window 1a over the alignment window and hence the bar code 30. 
     Thus, an efficient operation can be achieved by swinging the scanner 1 on the hinge 22 and whereby the fixing portion 24 of the scanner 1 makes positioning easy to read a shorter bar code 30 or by sliding the slider 21 to read a longer bar code 30. 
     In the third embodiment of the present invention with reference to FIG. 5, the guide 6 of the scanner comprises a plurality of switches, e.g., S1, S2 and S3 wherein the guide 6 fits to the slider 10 turning on the switches. 
     In the case that the size D of the reading window of the scanner 1 is a size of the order of 35 mm, there is provided that the slider 10 has six positioning holes 11a-11f in 35 mm pitch in order to verify accuracy of the bar code 30 having a length of 193 mm. 
     In the preferred embodiment, when the projection 7 of the scanner 1 fits into the positioning hole 11a, dents (i.e. recesses) 12 corresponding to the switches S2 and S3 are made so as to turn on the switch S1 and off the switches S2 and S3. Therefore, the bit pattern &#34;001&#34; can be detected reading the output of the switches S1, S2 and S3 sequentially. 
     Likewise, when the projection 7 fits into the positioning hole 11b, the bit pattern &#34;010&#34; can be detected by turning on only the switch S2. Similarly, the bit pattern &#34;011&#34; at the positioning hole 11c, the bit pattern &#34;100&#34; at the positioning hole 11d, the bit pattern &#34;101&#34; at the positioning hole 11e, and the bit pattern &#34;110&#34; at the positioning hole 11f, thus, the outputs of the switches S1-S3 shows a user relative position where the reading has been done. 
     Accordingly, if a divided bar code 30 fails to be completely read, erroneous reading of the bar code 30 can be detected by, e.g., monitoring the outputs of the switches S1-S3 in a microcomputer, and even if the user accidentally distorts reading sequence corresponding to the positioning holes 11a-11f, the sequence can be reconstructed according to the corresponding outputs of the switches S1-S3. 
     Thus, it is possible to obtain a reading error free scanner. A scanner also comprises a plurality of switches identifying a coordinate whereon a bar code is split by means of combination of ON/OFF so as to detect partial reading or a failure of reading sequentially.