Abstract:
A recording device is disclosed according to which writing information is recorded and the writing position in which the record head writes the information on a recording medium is detected. A discriminator determines the width of the recording medium loaded in the device, and a controller responsive to the discriminator and the detector controls the movement of the record head.

Description:
This is a continuation, of application Ser. No. 843,166, filed Oct. 17, 1977, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a recording device with which paper webs of various widths may be used. 
     2. Description of the Prior Art 
     These years have seen increasing need for recording paper webs of various widths to be used in compliance with various usages which have resulted from the diversified types of information, whereas printers such as relatively small recording devices heretofore used have limited the width of available recording paper web to only one size and so, different printers had to be chosen for use in compliance with the various usages. 
     As a solution to this problem, it would occur to mind to provide a paper guide 2 movable widthwise of recording paper 1 and to provide means for moving the paper guide 2 in accordance with the width of the paper 1 to control the recording paper 1, as shown in FIG. 1 of the accompanying drawing. 
     In conventional printers, however, limit switches 4 and 4&#39; are fixedly disposed at the opposite extremities of the stroke of a printing head 3 for the detection of the home position of the printing head 3 and for the detection of the maximum number of print columns and, when recording paper 1 of narrow width is used, the presence of these fixed limit switches 4 and 4&#39; gives rise to an event that the printing head 3 moves beyond the width of the paper 1. 
     This offers a problem particularly in the case of printers such as thermosensitive print systems, discharge breakdown print systems or the like in which the printing head keeps contact with recording paper during non-printing mode. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a recording device improved in the above-noted points. 
     It is another object of the present invention to provide a recording device in which the amount of information written is controlled by means for determining the width of the recording medium and means for detecting the movement of the record head. 
     Other objects of the present invention will become apparent from the following detailed description of an embodiment of the invention taken in conjunction with the accompanying drawing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a perspective view of a printer according to the prior art. 
     FIG. 2 shows the construction of an embodiment of the present invention. 
     FIG. 3 illustrates a case where a web of recording paper narrower in width than that in FIG. 2 is used. 
     FIG. 4 illustrates a case where a web of recording paper narrower in width than that in FIG. 3 is used. 
     FIG. 5 is a signal block diagram of the embodiment of FIG. 2. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 2, it shows a printer as the recording device of the present invention with which recording paper webs of three different widths are usable. A zero position detector 5 for detecting the home position of the printing head 3 is fixed to the main body 6 of the printer. A first detector 7, a second detector 8 and a third detector 9 for detecting the movement of a carriage 10 to which the printing head 3 is attached are affixed to the main body 6 to detect the maximum numbers of print columns corresponding to the three sizes of paper width. The carriage 10 is provided with a light emitting means, a magnet 10a, etc. for the detection of movement. The zero position detector 5 may be either a contact type switch such as a spring contact, microswitch or the like, or a non-contact type switch such as a photocoupler (U.S. Pat. No. 3,648,050), reed switch, (U.S. Pat. No. 3,584,173 or No. 3,557,327) Hall element or the like. On the other hand, the first to third detectors 7-9 may preferably be the above-mentioned non-contact type switches so that they may not interfere with the movement of the carriage 10 to which the printing head 3 is attached. 
     A guide shaft 11 is mounted on the main body 6 with a degree of axial freedom, and the paper guide 2 is slidable on the guide shaft 11. Projections 12, 13 and 14 are secured to the guide shaft 11 at three locations thereon, and compression coil springs 17 and 17&#39; are mounted coaxially with the guide shaft 11 between the projection 12 and a left plate 15 and between the projection 14 and a right plate 16, respectively. 
     Another guide shaft 11a extends parallel to the guide shaft 11 and has the opposite ends thereof secured to the left plate 15 and the right plate 16. The paper guide 2 is mounted slidably also on the guide shaft 11a and designed for engagement with grooves α, β and γ formed in the guide shaft 11a. Such engagement is accomplished as by balls (not shown, see U.S. Pat. No. 3,988,744) provided in the paper guide 2 being projected into the grooves α, β and γ to fix the paper guide 2 with respect to the guide shaft 11a. Such grooves α, β and γ may suitably be formed in accordance with the various widths of recording paper. 
     A first switch 18 and a second switch 19 are provided adjacent to the opposite ends of the guide shaft 11 and arranged to be opened and closed by axial movement of the guide shaft 11. Microswitches 18 and 19 are best suited as these switches. 
     In FIG. 2 which refers to the case where recording paper 1 of the largest width (hereinafter referred to as the first recording paper) is mounted, the paper guide 2 forces the projection 14 rightwardly to the compression coil spring 17&#39;. The guide shaft 11 integral with the projection 14 is also moved rightwardly, so that both the first and second switches 18 and 19 are not in contact with the guide shaft 11, thus bringing about OFF position. 
     Where recording paper 1&#39; of medium width (hereinafter referred to as the second recording paper) is mounted, the paper guide 2 releases the compression of the compression coil spring 17&#39;, as shown in FIG. 3, so that the guide shaft 11 assumes a position determined by the actions of the compression springs 17 and 17&#39;. At this time, the first switch 18 is in ON position while being contacted by the guide shaft 11 and the second switch 19 is in OFF position. 
     Where recording paper 1&#34; of the narrowest width (hereinafter referred to as the third recording paper) is mounted, the paper guide 2 forces the projection 13 leftwardly, as shown in FIG. 4, thus compressing the compression coil spring 17. The guide shaft 11 integral with the projection 13 is also moved leftwardly, so that both the first and second switches 18 and 19 assume ON position. 
     Finally, the output signals from the first detector 7, the second detector 8 and the third detector 9 are made to provide a carriage return signal for the printing head 3 by the wiring through the first and second switches 18 and 19, in the manner as shown in FIG. 5. 
     With the above-described construction, where the first recording paper 1 is loaded, both the first and second switches 18 and 19 are in OFF position so that the output signal from the first detector 7 provides a carriage return signal. Where the second recording paper 1&#39; is loaded, the first switch 18 is in ON position while the second switch 19 is in OFF position, so that the output signal from the first and second detectors 7 and 8 provide a carriage return signal. 
     Where the third recording paper 1&#39; is loaded, both the first and second switches 18 and 19 are in ON position, so that the output signals from the first, second and third detectors 7, 8 and 9 provide a carriage return signal. 
     An activated detector 7, 8 or 9 located nearest the home positon is first to act in accordance with a respective paper width, whereby the maximum number of print columns may be controlled for a respective paper width. 
     Thus, adoption of the present invention can provide a recording device which permits selective use of recording paper webs of various widths in accordance with the intended usage.