Apparatus for scanning originals

An apparatus for point by point and line by line scanning of originals or documents includes a fixed, transparent original carrier for an original. An illumination carrier is disposed above and parallel to the original carrier. An illumination unit is fixed to the illumination carrier for illuminating the original line by line. A base carrier parallel to the illumination carrier is disposed under the original carrier and an optoelectronic scanning head for converting scanning light into picture signals is fixed thereon. The illumination carrier and the base carrier are interconnected by a U-shaped connecting element. The connecting element has a rotary joint for pivoting the illumination carrier away from the original carrier with the illumination unit to facilitate access to the original carrier. The illumination unit and the scanning head perform a perpendicularly oriented feed movement in relation to scanning lines through the use of linear guides, in order to scan a surface of the original.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention relates to the field of electronic reproduction technology and relates in particular to an apparatus for scanning originals or documents opto-electronically point by point and line by line. The apparatus is referred to below as a scanner.

In a scanner which is constructed, for example, as a flatbed scanner for transmitted light scanning, a transparent original to be scanned is located on a fixed-position, transparent and flat original carrier. The original is illuminated line by line by an illumination unit. A scanning head having an optoelectronic converter, for example in the form of a row of photodiodes, is disposed on a side of the original carrier which faces away from the illumination unit. Scanning light modulated by lightness values of scanned image points is converted in the optoelectronic converter of the scanning head into electrical image signal values.

In order to two-dimensionally scan the original, the illumination unit and the scanning head are moved synchronously over the original, at right angles to the direction of the scanning lines, through the use of a suitable feed drive.

Flatbed scanners are already known in which the illumination unit and the scanning head are guided separately and are each moved by an feed drive. The synchronous movement of the illumination unit and the scanning head is achieved through the use of appropriate control of the two feed drives. As a result of the separate mechanical guides for the illumination unit and the scanning head, and as a result of the expenditure on control, such a device is relatively complicated.

UK Patent Application GB 2 323 732 A has already disclosed a flatbed scanner which is identical to the generic type and in which an illumination unit disposed above an original carrier and a scanning head disposed underneath the original carrier are coupled to each other through a rigid connecting element and are moved in the feed direction by a common drive. The illumination unit can be pivoted onto an edge of the original carrier, parallel to the original carrier, and can be locked there during transport.

European Patent Application 0 516 092 A2, corresponding to U.S. Pat. No. 5,251,072, specifies a flatbed scanner in which the illumination unit and the scanning head are likewise mechanically coupled through a connecting element and are driven jointly in the feed direction. In the case of that flatbed scanner, the illumination unit can be plugged into the connecting element from above.

A similar flatbed scanner is disclosed by U.S. Pat. No. 5,218,485.

SUMMARY OF THE INVENTION

It is accordingly an object of the invention to provide an apparatus for scanning originals opto-electronically point by point and line by line, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type in such a way that, with straightforward expenditure on device technology, both synchronous movement of an illumination unit and a scanning head as well as a great degree of user friendliness are ensured.

With the objects of the invention in view, there is also provided an apparatus for scanning originals point by point and line by line, comprising a fixed-position original carrier for an original. The original carrier has a long side and a longitudinal direction. A pivotal illumination device is disposed above the original carrier and is extended in a line direction over the original carrier, for illuminating the original line by line. An optoelectronic scanning head is disposed underneath the original carrier, for converting scanning light into image signals. A connecting element is movable at the long side of the original carrier. The connecting element carries the illumination device and the scanning head and executes a feed movement at right angles to the line direction, for two-dimensionally scanning the original. The connecting element has a rotary joint with an axis of rotation extended in the longitudinal direction of the original carrier, for pivoting the illumination device about the rotary joint away from the original carrier into a plane oriented at an angle to the original carrier.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the figures of the drawings in detail and first, particularly, toFIG. 1thereof, there is seen a cross sectional representation of an exemplary embodiment of a flatbed scanner. An original or document2to be scanned, for example a transmitted-light original, is disposed on a fixed-position, transparent original carrier or support1. The original carrier1is fixed through the use of a holder3to a housing4of the flatbed scanner. A scanning carriage5has an illumination carrier6disposed above the original2and a base carrier7disposed underneath the original2. A transmitted light illumination unit8, for example in the form of a fluorescent tube, for illuminating the original2line by line, is fixed to the illumination carrier6. The illumination carrier6and the illumination unit8together form a pivotal illumination device. A scanning head9is fitted to the base carrier7. The scanning head9has a scanning objective10and an optoelectronic converter11which, for example, is constructed as a row of photodiodes oriented in the direction of scanning lines. The base carrier7is configured in such a way that scanning light coming from the original2, unimpeded by the scanning objective10, can fall onto the optoelectronic converter11, in which the scanning light modulated by brightness values of scanned image points can be converted into electric image signal values.

The illumination carrier6and the base carrier7are connected to each other by a connecting element12, which extends in a U shape around one side of the original carrier1. In order to two-dimensionally scan the original2, the scanning carriage5with the transmitted light illumination unit8and the scanning head9executes a feed movement over the original2, oriented at right angles to the direction of the scanning lines, that is to say at right angles to the plane of the drawing. The scanning carriage5is guided by linear guides13,14fixed to the housing4. The feed movement of the scanning carriage5is carried out, for example, through the use of a non-illustrated advance motor. A corresponding reflected light illumination unit15is fitted to the base carrier7of the scanning carriage5, in order to scan reflected light originals.

The illumination carrier6with the transmitted light illumination unit8is disposed in such a way that it can be pivoted away from the original carrier1, in order to obtain better access to the original carrier1. To this end, the connecting element12has a rotary or pivot joint16, with an axis of rotation which extends in the feed direction of the scanning carriage5.

A dividing plate17which, for example, is formed of a transparent material, like the original carrier1, is disposed between the transmitted light illumination unit8and the original2. The illumination carrier6, with the transmitted light illumination unit8, is supported on the dividing plate17through the use of a roller19during the feed movement.

The housing4has an appliance cover18that can be folded or pivoted up and is disposed above the transmitted light illumination unit8. When the appliance cover18is folded up, the dividing plate17and the illumination carrier6with the transmitted light illumination unit8are folded up at the same time through the use of a coupling element20. In order to avoid any relative movement between the appliance cover la and the illumination carrier6, a non-illustrated axis of rotation of the appliance cover18expediently coincides with the axis of rotation of the rotary joint16.

In the vicinity of the rotary joint16, edge regions of the appliance cover18and of the housing4of the flatbed scanner have a rounded shape, for example a quarter circular arc, in such a way that a pivoting movement of the appliance cover18that overlaps the housing4is achieved. This means that injuries to an operator, for example crushed fingers, can be avoided.

Likewise, the holder or mounting3for the original carrier1in the vicinity of the rotary joint16is provided with a rounded course, which means that manual access to the rotary joint16is prevented in all conceivable pivoting positions.

The relative association between the scanning head9and the transmitted light illumination unit8is preferably carried out in such a way that, in the operating position illustrated inFIG. 1, the result is a substantially parallel configuration of the scanning head9and the transmitted light illumination unit8as well as a configuration of the elements8and9one above the other using the smallest possible spacing. In this way, both uniform illumination and high utilization of the available light intensity can be assisted.

FIG. 2shows a further cross-sectional illustration of the flatbed scanner in which the dividing plate17and the illumination carrier6with the transmitted light illumination unit8have been pivoted or folded up, at the same time as the appliance cover18. In the position shown, the original carrier1is easily accessible, and the original2can be laid on the original carrier1or removed from the latter in a straightforward manner. The rounded contoured regions of the housing4and of the appliance cover18have been pushed one over the other in the manner of a shell. It is also possible to see that the rotary joint16is covered by the rounded contour of the holder or mounting3even in the folded or pivoted-up position.

When the appliance cover18has been folded up, it is possible to lay relatively thick reflected light originals, for example pages of a book, on the original carrier1and to scan them. In this operating mode, the illumination is provided exclusively by the reflected light illumination unit15.