to better understand the present invention , a number of preferred embodiments , together with drawings , will be elaborated in the following . in fig1 a , when the outside ( facsimile transmission department 300 ) sends a facsimile document 310 to a mfp with document management device 100 , the document management device 100 will perform a document receiving task 180 , followed by a document saving task 190 . in fig1 b , when the internal uses a mfp 200 with document management device 100 to save a document , firstly the mfp 200 is used to perform a document scanning step 210 for scanning the document , and transmitting the scanned document to the document management device 100 . the document management device 100 perform a document receiving task 180 , followed by a document saving task 190 . in fig1 c , when the internal uses a computer 205 to save a document , firstly a document transmission step 210 is performed to sent the document to the document management device 100 . the document management device 100 perform a document receiving task 180 , followed by a document saving task 190 . in fig2 , when a user wants to search an existing electronic document , a computer 205 is used to perform uploading a feature word 292 , and one or more feature words are uploaded to the document management device 100 . the document management device will perform a step for receiving the uploaded information 192 , a search task 194 , and then a step of document downloading 196 , so that the searched result ( a document meeting the search conditions , or “ null ” message ) is downloaded to the computer 205 . the user performs a step of receiving the downloaded document 296 in order to obtain the search result . fig3 a shows a schematic structure of a document management device 100 connected to a mfp 200 according to the invention , wherein the document management device 100 contains a file receiving device 120 , an optical identification device ( ocr ) 130 , a database 140 and a feature mark identification device 150 . the mfp 200 contains a facsimile mechanism 210 , scanning mechanism 220 , printing mechanism 230 , and photocopying mechanism 240 . the document management device 100 and the mfp 200 are connected with a transmission component , indicated by a line segment in the figure . the operations of the device are the same as described above . fig3 b shows a schematic structure of a document management device 100 integrated with a mfp 200 according to the invention , wherein the document management device 100 contains a file receiving device 120 , an optical identification device ( ocr ) 130 , a database 140 and a feature mark identification device 150 . the mfp 200 contains a facsimile mechanism 210 , scanning mechanism 220 , printing mechanism 230 , and photocopying mechanism 240 . the document management device 100 and the mfp 200 are combined into an integral assembly , shown with an external frame in the diagram . this diagram can also be viewed as a structural block diagram of a multifunctional printer device with document management function . the operations of the device are the same as described above . fig3 c shows a schematic structure of a multifunctional printer device with document management function 800 according to the invention , which contains a file receiving device 810 , an optical identification device ( ocr ) 820 , a database 830 , a feature mark identification device 840 , a facsimile mechanism 850 , a scanning mechanism 860 , a printing mechanism 870 , and a photocopying mechanism 880 . the operations of the device are the same as described above . as shown in fig4 , when the document management device has received the electronic document ( receiving electronic document 510 ), a step 520 of dissecting the electronic document will be performed immediately in order to dissect the header content of the electronic document ; a coarse classification step 530 is then performed on the information dissected from the header content . an optical character recognizing step 540 is performed on the non - textural content in the electronic document , followed by a step of setting up features 550 according to the ocr recognizing results and the text content of the electronic document . subsequently , the cyclone search engine is used to identify a feature mark 560 from the features . the feature mark is used to set up an index 570 for using as a basis for searching the document , while a fine classification 580 is preformed on the feature mark . the classification results ( coarse classification plus fine classification ) are used as a base for storing the electronic document by performing a file storage step 590 . as shown in fig5 , when the document management device has received the electronic document ( receiving electronic document 510 ), a step 520 of dissecting the electronic document will be performed immediately in order to dissect the header content of the electronic document ; a classification step 530 is then performed on the information dissected from the header content . an optical character recognizing step 540 is performed on the non - textural content in the electronic document , followed by a step of setting up features 550 according to the ocr recognizing results and the text content of the electronic document . subsequently , identifying a feature mark 560 from the features is performed . the feature mark is used to set up an index 570 for using as a basis for searching and outputting the document . the classification results from the header content are used as a base for storing the electronic document by performing a file storage step 590 . as shown in fig6 , when the document management device has received the electronic document ( receiving electronic document 510 ), a step 520 of dissecting the electronic document will be performed immediately in order to dissect the header content of the electronic document ; a classification step 530 is then performed on the information dissected from the header content . the classification results are used as a basis for storing the electronic document by performing a file storage step 590 . an optical character recognizing step 540 is performed on the non - textural content in the electronic document , followed by a step of setting up features 550 according to the ocr recognizing results and the text content of the electronic document . subsequently , identifying a feature mark 560 from the features is performed . the feature mark is used to set up an index 570 for using as a basis for searching and outputting the document . fig7 is a flowchart showing detailed steps of the step of fine classification 580 in fig4 , which is next to the step of identifying the feature mark 560 , and involves searching a key word in the feature mark . as shown in fig7 , a step 581 is performed to determine the existence of key word ; if a key word exists , the key word is used to further perform a classification 582 based on the key word , and then a ( fine ) classification 586 is completed ; if no key word exists , a user will have to decide whether to perform a manual classification 583 . a classification 584 is performed according to an input value , if the user decide to perform the manual classification , and the input content is used to complete the ( fine ) classification ; if no , a step of no fine classification 585 is performed , and the ( fine ) classification 586 is completed . fig8 is a flowchart showing another way for carrying out the step of fine classification 580 in fig4 , which is next to the step of identifying the feature mark 560 , and involves searching a key word in the feature mark . as shown in fig8 , a step 581 is performed to determine the existence of key word ; if a key word exists , the key word is used to further perform a classification 582 based on the key word , and then a ( fine ) classification 586 is completed ; if no key word exists , a step of no fine classification 585 is performed , and the ( fine ) classification 586 is completed . as shown in fig9 , a step of receiving search information 610 triggers the device performing a step of search task 620 to perform searching according to the search conditions , followed by a step of determining the existence of a file 630 or not in order to determine whether there is a file which meets the search information . if the answer is affirmative , the device will perform a step of downloading file information 640 in order to download the target file to the user ; if the answer is negative , the device will perform a step of downloading a search result 650 in order to transmit a message of “ no file meeting search conditions ” to the user . fig1 shows a flowchart of a preferred embodiment according to the invention . as shown in fig1 , when the document management device has received the electronic document ( receiving electronic document 510 ), a step 520 of dissecting the electronic document will be performed immediately in order to dissect the header content of the electronic document ; a classification step 530 is then performed on the information dissected from the header content . the classification results are used as a basis for storing the electronic document by performing a file storage step 590 . next , a step of determining the existence of non - textural content 542 is performed to determine the existence or not of “ non - textural content ” in the document . if the answer is affirmative , an optical character recognizing step 540 is performed on the non - textural content in the electronic document , followed by a step of setting up features 550 according to the ocr recognizing results and the text content of the electronic document . if the answer is negative , the step of setting up features 550 according to the text content of the electronic document is performed . subsequently , identifying a feature mark 560 from the features is performed . the feature mark is used to set up an index 570 for using as a basis for searching and outputting the document . furthermore , taking the specification of this invention as an example , the step of optical character identification 540 , the step of setting up features 550 , the step of identifying feature mark 560 , and the step of setting up index 570 , will be described in the following , as well as the search of the document . the contents of the present invention include : title of the invention , field of the invention , background of the invention , summary of the invention , . . . , claims , abstract , and drawings , wherein the title of the invention , background of the invention , summary of the invention , . . . , claims , and abstract are textural content , and the drawings are non - textural content . therefore , in the step of optical character recognizing 540 , the ocr device performs an optical character recognition task on the drawings . taking fig1 a as an example , after ocr , the textural content of “ 300 facsimile transmission department ”, “ 310 facsimile document ”, “ 100 document management device ”, “ 180 receiving document ”, and “ 190 saving document ” are obtained . in the step of setting up features 550 , the textural content obtained in the optical character recognizing 540 step is combined with the original textural content ( title of the invention , field of the invention , background of the invention , summary of the invention , . . . , claims , abstract ) to form features . in the step of identifying the feature mark 560 , the feature mark identification device performs a feature mark identification task on the features set up in the setting up step 550 . taking the title of the invention as an example to perform the feature mark identification , the feature words of “ identification , classification , search , save , document , management , device ” are obtained . taking the text in fig1 a obtained by ocr as an example to perform the feature mark identification , the feature words of “ facsimile , transmission , department , document , management , device , receiving , and saving ” are obtained . in the step 570 of setting up an index , the device uses the feature words obtained in the feature mark identification step 560 to execute an indexing program on a to - be - stored document ( flowcharts shown in fig4 or fig5 ) or a stored document . if the device automatically set the file name as “ document management device with identification , classification , search , and save functions ” ( hereinafter abbreviated as document management device ), taking an example of using the feature words contained in the title of the invention , the device will automatically generate an index table of feature words , as shown in table 1 . taking the feature words contained in fig1 a as an example , the device will automatically generate an additional index table of feature words , as shown in table 2 . the index in table 2 does not contain feature words of “ document ”, “ document management ”, “ document management device ”, “ management ” “ management device ” and “ device ”, as the above - mentioned feature words have been shown in table 1 . after saving the document and setting up the index tables , the device &# 39 ; s user can use the feature word to search / display / download the document . for example , the user uses “ save ” to perform search of feature words . the document management device 100 receives the search information in the step 610 of receiving search information , and immediately executes the search task step 620 to check for whether the index tables containing the feature word “ save ” ( determining existence of file step 630 ). the search results show that the index table 1 contains the feature word “ save ”. therefore , the step 640 of downloading file information is executed subsequently , i . e . the document management device will download this file to the user end . after receiving the information , the user can decide on his / her own to display and / or download the file .