Image Forming Method and Apparatus Which Determine Stapling Position Using an Orientation by an Image and a Sheet Feed Direction

The present invention relates to an image forming apparatus having a finisher capable of stapling a stack of sheets at any one of a plurality of positions.

Copiers, printers or similar image forming apparatuses having a finisher are extensively used today. Conventional finishers include one capable of sorting sheets carrying images thereon and then stapling a stack of such sheets together. Moreover, some finishers with such a stapling function are selectively operable in any one of modes for stapling a sheet stack at a single predetermined point and modes for stapling it at a plurality of predetermined points.

However, the problem with a finisher operable in such different modes is that the stapling position or positions have to be selected in consideration of the orientation of documents, sheet feed direction, and the orientation of characters (image). This requires troublesome operation and, therefore, often results in defective stapling.

It is, therefore, an object of the present invention to provide an image forming apparatus which frees a finisher thereof from defective stapling.

An image forming apparatus having a finisher capable of selecting a plurality of stapling positions of the present invention comprises a recognizing device for recognizing the orientation of an image, and a control device for automatically determining a stapling position on the basis of the orientation of an image and a sheet feed direction.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken with the accompanying drawings in which:

FIG. 1 is a section showing an image forming apparatus embodying the present invention;

FIG. 2 is an enlarged side elevation of a staple tray included in a finisher forming part of the embodiment;

FIG. 3 is an enlarged view of a stapler included in the finisher;

FIG. 4 is a view showing a specific arrangement of an operation panel provided on the apparatus of FIG. 1;

FIG. 5 is a flowchart representative of a main routine to be executed by the embodiment;

FIG. 6 is a flowchart representative of a subroutine included in the main routine;

FIG. 7 shows stapling positions which allow stapling to be performed;

FIG. 8 shows stapling positions which do not allow stapling; and

FIG. 9 demonstrates single point stapling and two point stapling.

As shown in FIG. 9, some conventional finishers applicable to a copier, printer or similar image forming apparatus are operable in three different staple modes (I), (II) and (III). In the mode (I), the finisher staples a stack of sheets S at a single point P adjacent to the upper left corner, as viewed in the figure. In the mode (II), the finisher staples the sheets S at a single point P adjacent to the lower left corner. Further, in the mode (III), the finisher staples the sheets S at two spaced points P lying in the left margin. The problem with with this type of finisher is that the stapling position or positions have to be selected in consideration of the orientation of documents, sheet feed direction, and the orientation of characters (image), as stated earlier. This requires troublesome operation and, therefore, often results

in defective stapling.

Referring to FIGS. 1-4, an image forming apparatus with a finisher embodying the present invention is shown and implemented as a digital copier by way of example. As shown, the copier, generally 3, is provided with a recycling document handler (RDH) 4 and a finisher 5. The RDH 4 may be replaced with an automatic document feeder (ADF) if the copier 3 has an electronic sorting function. Sheets, or copies, sequentially coming out of the copier 3 are introduced into the finisher 5 and routed through a path indicated by a thick line in FIG. 1 to a staple tray 6. Every time a sheet is stacked on the staple tray 6, jogger fences 7 and 8 are operated to position it. After the last sheet has been stacked on the staple tray 6, a stapler 9 is actuated to staple the whole stack of sheets. The stapled sheet stack is transported to a stack tray 11 by a belt 10 having pawls. The stapler 9 is mounted on a base 12 and driven by a staple motor 15 to move in a direction parallel to the trailing edge of the sheet stack.

The copier 3 having the above construction has various functions, as follows. To begin with, the copier 3 automatically determines a stapling position matching the orientation of an image (horizontal writing or vertical writing) and the sheet feed direction (longitudinal feed or lateral feed). When a two point staple command is entered on the copier 3 by the operator, the copier 3 inhibits the stapling position from being automatically determined. When the stapling position is inhibited from being automatically determined, the copier 3 urges the operator to enter a desired stapling position in a manual mode. Also, in such a condition, the copier 3 produces an alarm for urging the operator to change the orientation of documents. When the operator enters a desired stapling position in the manual mode, the copier 3 compares it with an automatically determined position and, if the former differs from the latter, produces an alarm. When stapling is continuously repeated at the same stapling position, the copier 3 simply causes the second and successive sets of copies to be stapled at the same position as the first set of copies. The copier 3 is capable of determining a stapling position on the basis of the page corresponding to the cover of a stack of documents. Moreover, when two point stapling is commanded by the operator, the copier 3 determines whether or not the beginning of the writing is located at the stapling side and, if the result of decision is negative, produces an alarm.

FIG. 4 shows a specific arrangement of an operation panel provided on the copier 3. As shown, the operation panel includes a copy start button 13, an automatic staple key, manual staple keys 17, 18 and 19, a display 20, and numeral keys 21.

A reference will be made to FIGS. 5 and 6 for describing a control procedure particular to the embodiment. Assume that the operator has set a stack of documents on the RDH 4 and then pressed the copy start button 13. Then, the copier 3 determines a finishing mode desired by the operator. At this instant, the RDH 4 sends data representative of a document feed direction to the copier 3. As a document is fed by the RDH 4 to a glass platen (see FIG. 1), the copier 3 reads it with a CCD (Charge Coupled Device) array 14, FIG. 1, to determine the orientation of the document image. This is done on the basis of the page corresponding to the cover of the documents. Whether the page corresponding to the cover is fed first or last is determined by the RDH 4 itself beforehand. The copier 3 determines a stapling position in response to data representative of a copy feed direction and data representative of the image orientation. At the same time, the copier 3 determines whether or not the image orientation is one which allows stapling to be performed. It is to be noted that the image orientation which allows stapling is any one of orientations (I)-(VIII) shown in FIG. 7. FIG. 8 shows image orientations (I)-(IX) which do not allow stapling; when documents are set such that sheets S will be discharged in any one of the orientations (I)-(IX) of FIG. 8, stapling is inhibited. In the subroutine shown in FIG. 6, (I)-(VII) correspond to (I)-(VII) of FIG. 7, respectively.

When an automatic staple mode is selected on the automatic staple key 16, FIG. 4, the copier 3 determines a stapling position and, if stapling is allowed, drives the staple motor 15, FIG. 2. As a result, the stapler 9 is moved to the position determined by the copier 3. If stapling is not allowed, the copier produces an alarm message, e.g., "Enter a stapling position or reorient documents" on the display 20, FIG. 4. This is successful in reducing defective stapling.

Further, when the operator selects either of top stapling or bottom stapling on the manual staple key 18 or 17, FIG. 4, the copier 3 determines a stapling position and whether or not stapling is allowed. If the result of this decision is negative, the copier 3 produces an alarm message, e.g., "Change stapling position" on the display 20. This is also successful in reducing defective stapling.

On the other hand, when the operator selects two point stapling on the two point key 19, FIG. 4, the copier 3 determines whether or not stapling is allowed and, if it is not allowed, displays an alarm message, e.g., "Check stapling position" or "Reverse document orientation". Consequently, documents are prevented from being set on the RDH 4 in a wrong orientation.

In summary, it will be seen that the present invention provides an image forming apparatus having various unprecedented advantages, as enumerated below.

(1) The apparatus automatically determines a stapling position matching the orientation of an image and a sheet feed direction, thereby reducing defective stapling.

(2) When a two point staple command is entered on the apparatus in a manual mode, the apparatus inhibits the stapling position from being automatically determined. This allows a sheet stack to be surely stapled at two points.

(3) When the stapling position is inhibited from being automatically determined, the apparatus urges the operator to enter a desired stapling position in a manual mode. Also, in such a condition, the apparatus produces an alarm for urging the operator to change the orientation of documents. Therefore, even when documents are accidentally oriented such that the end of a writing is located on the stapling side, they can be readily recovered.

(4) When the operator enters a desired stapling position in the manual mode, the apparatus compares it with an automatically determined position and, if the former differs from the latter, produces an alarm. The apparatus, therefore, prevents the operator from entering unexpected commands.

(5) When the same stapling operation is continuously performed, the apparatus simply causes the second and successive sets of copies to be stapled at the same position as the first set of copies, thereby enhancing productivity.

(6) The apparatus determines a stapling position on the basis of the page corresponding to the cover of a stack of documents and is, therefore, free from erroneous decision on the stapling position.

(7) When two point stapling is commanded by the operator, the apparatus determines whether or not the beginning of the writing is located at the stapling side and, if the result of decision is negative, produces an alarm. This insures accurate orientation of documents in the two point staple mode.

Various modifications will become possible for those skilled in the art after receiving the teachings of the present disclosure without departing from the scope thereof.