Background of the Invention
This invention relates to a mail processing apparatus, and more particularly to an address reading apparatus for a mail article, the apparatus being adapted to read the address description on either surface of the mail article.
A mail processing apparatus reads an address description on a mail article having various thicknesses. Two reading devices are frequently provided for reading both sides of a transfer path in order that address reading can be done regardless of which surface of the mail article is presented for reading.
A conventional address reading apparatus of this kind including two reading devices on opposite sides of a transfer path has a construction shown in FIG. 1. This apparatus comprises address readers 1 and 2 disposed in opposition to each other on both sides of a transfer path for reading an address description on a mail article. Pinch rollers 3 and 4 are disposed at the inlet and the outlet of the address readers 1 and 2. Pressure rollers 5 and 6 are disposed in contact with the pinch rollers 3 and 4. Guide plates 7 and transfer belts 8 and 9 form the transfer path. Address description detectors 10 and 11 are disposed on both sides the transfer path and upstream of the address readers 1 and 2.
The address description detectors 10, 11 detect the surface of the mail article on which the address description is written. To this end, the detectors 10 and 11 sense, for example, a postage stamp and a particular mark indicating the surface carrying the address description of the mail article. Therefore, before the mail article reaches the address readers 1 and 2, the system has detected which surface is carrying the address that is present on either the upward or the downward surface. When the mail article is transferred to a location between the address readers 1 and 2, it is held by a pair comprising the pinch roller 3 and the pressure roller 5 and by a pair comprising the pinch roller 4 and the pressure roller 6. The address description is read out by one of the address readers 1 and 2.
In FIG. 1, the pinch rollers 3 and 4 are rotated at fixed positions. The pressure rollers 5 and 6 are movably pressed against the rollers 3 and 4 by means of levers and suitable springs 12 and 13. Accordingly, when the mail article is held between the pinch rollers 3 (4) and the pressure rollers 5 (6), the pressure rollers 5 and 6 are moved in accordance with a thickness of the mail article.
In the above-described conventional address reading apparatus, the distance between the address reader 1 on the side of the pinch rollers 3 and 4 and a surface of a mail article is kept constant. However, the distance between the address reader 2 on the side of the pressure rollers 5 and 6 and the surface of the mail article varies by at least the thickness of the mail article since the pressure rollers 5 and 6 are moved away from their normal position in accordance with the thickness of the mail article. Therefore, the address reader 2 does not have a fixed distance focus upon the image of the address description formed on a scanning device via a lens. Accordingly, the address description cannot always be read accurately. Such a drawback is affected to a great amount, especially, when a mail article of 5 to 6 mm in thickness is processed.
It is possible to use an optical system having a deep focused range and having a mechanism for focusing a lens in accordance with the distance to the surface of a mail article to be read in order to overcome the drawback. However, such an optical system becomes complicated and expensive, and is not practical.
Summary of the Invention
It is, therefore, an object of the present invention to provide an address reading apparatus for a mail article, which is capable of eliminating the drawback encountered in the above-described conventional address reading apparatus, while using a simple optical system.
According to the present invention, an address reading apparatus for a mail article provides an image of an address description on either surface of a mail article which is accurately focused by a scanning device in the address readers of both sides of the path, irrespective of the thickness of the mail article.
The address reading apparatus of the present invention comprises two address readers disposed on opposite sides of a transfer path, in opposition to each other for reading an address description on a surface of a mail article. An address-carrying surface detector is disposed upstream of the two address readers and is disposed along the transfer path for detecting an address description-carrying surface of the article. Two roller pair mechanisms are provided at the inlet and the outlet of the address readers. Two pressure rollers in each roller pair mechanism are disposed on opposite sides of the transfer path and engage each other to hold with mail article therebetween. The pressure roller driving means is responsive to an output signal delivered from the address-carrying surface detector for fixing either pressure roller at a predetermined position, whereby the distance is constant between the address description-carrying surface and the address reader facing the address surface.
Brief Description of the Drawings
FIG. 1 shows the constructive diagram of a conventional address reading apparatus for a mail article;
FIG. 2 shows a constructive diagram of an embodiment according to the present invention; and
FIG. 3 is a block diagram of a control circuit for the embodiment of FIG. 2 .
Description of the Preferred Embodiment
An embodiment of the present invention will now be described with reference to the drawings. In FIG. 2, showing an embodiment of the present invention, two address readers 1 and 2 are provided for reading an address description on either surface of a mail article. The guide plates 7, transfer belts 8 and 9 and detectors 10 and 11 are identical with the corresponding parts shown in FIG. 1.
In greater detail, each of the address readers 1 and 2 includes light sources 1a and 1b, a scanning device 1c, and a lens 1d for focusing an image of the address description onto the scanning device 1c. The guide plates 7 are provided in front of the address readers 1 and 2. In this embodiment, the focus of lens 1d in the scanning device 1c in the address readers 1 and 2 is fixed on an ideal transport path position TP. Therefore, a very simple and inexpensive optical system can be employed in the present invention.
In a feature of the present invention, pressure rollers 14, 15, 16 and 17 are provided in addition to the parts arranged as mentioned above. These pressure rollers are disposed at the inlet and the outlet of the address readers 1 and 2, along the transfer path. The pressure rollers 14 and 16 (15 and 17) are provided on both sides of the transfer path and are engaged with each other at the ideal transfer path position TP. A suitable force level is maintained by means of arms 18 and 20 (19 and 21) and by springs 22 and 24 (23 and 25). In this case, the pressure rollers 14 to 17 are rotated at the same speed as the transfer speed.
Stoppers 26 to 29 are provided with respect to the arms 18 to 21 so that the pressure rollers 14 to 17 do not press against the opposed pressure rollers across the ideal transfer path position TP. On their rotary centers, the arms 18 to 21 are provided with solenoids 30 to 33. When a driving current is applied to these solenoids, the arms are pressed against the stoppers 26-29, so that the pressure rollers can not move away from the ideal transport path position TP. In addition, a mail article detector 34 (FIG. 3) is provided upstream of the address readers 1 and 2, so as to produce a solenoid-driving timing.
The operation of the embodiment of the present invention will now be described with reference to FIG. 2 and FIG. 3 showing the block diagram of a control circuit. As previously mentioned, the address description-carrying surface has indicating information such as a predetermined mark or a postage stamp. This information is detected by the detectors 10 and 11 (FIG. 2) which are provided on opposite sides of the transfer path. The outputs from the detectors 10 and 11 are sent to an address-carrying surface judging circuit 35 (FIG. 3). An output signal S.sub.1 or S.sub.2, representative of the address-carrying surface, is delivered from the circuit 35.
When the address-carrying surface faces the address reader 1, for example, the output signal S.sub.1 is supplied from the circuit 35 to a rotary solenoid driving circuit 36. Consequently, the rotary solenoids 30 and 31 (FIG. 2) associated with the driving circuit 36 are actuated to press the arms 18 and 19 against the stoppers 26 and 27. As a result, the rims of the pressure rollers 14 and 15 are in fixed positions at the ideal transfer path position TP. The surface of the mail article which is to be scanned by the address reader 1 is thereby fixed at a position where lens 14 is in focus. During this time, the other pressure rollers 16 and 17 contacting these pressure rollers 14 and 15 are moved away (moved down in FIG. 1) from the ideal transfer path position TP in accordance with the thickness of the mail article, since the solenoids 32 and 33 are not activated.
Conversely, when the judgement circuit 35 judges that the address-carrying surface faces the address reader 2, the output signal S.sub.2 is supplied from the circuit 35 to a rotary solenoid driving circuit 37 to actuate the rotary solenoids 32 and 33. As a result, the rims of the pressure rollers 16 and 17 are in fixed positions at the ideal transfer path TP position. In this embodiment, the mail article detector 34 is adapted to supply a reference signal for driving timing to the rotary solenoid driving circuits 36 and 37. In FIG. 3, read-out signals delivered from the address readers 1 and 2 are supplied to a selecting circuit 38. One of the two read-out signals is selected in accordance with a selecting signal S.sub.3 delivered from the address-carrying surface judging circuit 35. The selected read-out signal is sent to a recognition processing circuit 39.
According to the present invention as described above, in the case of providing two address readers on opposite sides of the transfer path, the distance between the scanning device in the address reader and the address-carrying surface of the mail article can be fixed and constant with respect to both the address readers, irrespective of the thickness of the mail article even when the address description is present on either surface of the mail article. This prevents a de-focus and, therefore, the address description on the mail article can be read-out accurately.