Abstract:
A document feeder is formed of a transfer path for allowing a document to pass therethrough, a transferring device situated along the transfer path for transferring the document along the transfer path, a stamping device situated near the transfer path for impressing a mark on a surface of the document transferred by the transferring device, and a setting device connected to the stamping device for setting a density of the mark on the document impressed by the stamping device so that the mark impressed on the document becomes substantially constant in the density when it is used. A driving device is connected to the transfer device for controlling a transferring speed of the document by the transferring device in accordance with density information set by the setting device. Therefore, even if ink itself in the stamping device is consumed, impressed mark can be identified by a user by controlling the density of the impressed mark.

Description:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT 
     The present invention relates to a document feeder used in a combined machine having functions as a copier, printer, and facsimile, and more particularly, the present invention relates to a document feeder having a stamping device which impresses a document reading mark on a document. 
     There has been generally known a document feeder used in a combined machine having functions as a printer, facsimile or the like, wherein documents placed on a document table are sent sheet by sheet by paper supplying means, transferred by transferring means to pass through a reading section so that an image of the document is read by image reading means, and then ejected onto an ejection table. Among the document feeders, there is a document feeder attached with a stamping device for impressing a surface of the document with a mark for confirming whether reading the document is completed or not. 
     In the conventional document feeder provided with the stamping device, however, there has been a problem that when ink itself in the stamping device is consumed, impressing becomes lighter, so that a user can not confirm the mark easily. 
     Also, there has been a problem that impressing is not appropriately performed since ink is not adhered on the document or the ink is blurred depending on a kind of the document. 
     An object of the present invention is to provide a document feeder provided with a stamping device, wherein a density of an impressed mark is adjustable so that even if ink itself in the stamping device is consumed, a user can definitely identify the impressed mark. 
     SUMMARY OF THE INVENTION 
     To solve the above problem, the present invention provides a document feeder, which is formed of: transferring means for transferring a mark on a document along a transfer path; stamping means for impressing a surface of the document transferred by the transferring means; setting means for setting a density of impression by the stamping means; and driving means for controlling a transferring speed of the document by the transferring means in accordance with information of the set density by the setting means. 
     Also, the present invention provides a document feeder, which is formed of: a reading section for reading an image of a document; transferring means for transferring the document read by the reading section along a transfer path; stamping means for impressing a mark on a surface of the document transferred by the transferring means; document detecting means disposed in the transfer path; setting means for setting a density of impressing by the stamping means; and driving means for changing a transferring speed of the document from a first transferring speed to a second transferring speed according to a detected signal by the detecting means, and at the same time, for controlling the second transferring speed in accordance with information of the set density by the setting means. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a sectional view of a document feeder according to the present invention; 
     FIG. 2 is an enlarged sectional view of a main part of the document feeder; 
     FIG. 3 is an enlarged side view of a stamping device to be used in the document feeder; 
     FIG. 4 is a block diagram of a control section of the document feeder; 
     FIG. 5 is a chart showing a control flow of the document feeder in a non-stamp mode; 
     FIG. 6 is a chart showing a control flow of the document feeder in a stamp mode; 
     FIG. 7 is a chart showing a stamp speed setting control flow of the document feeder in a stamp mode; and 
     FIG. 8 is a chart showing a stamp speed setting control flow of another embodiment of the document feeder in a stamp mode. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Hereinafter, details of the embodiments of the present invention will be explained with regard to the drawings. 
     FIG. 1 shows a structural part of a document feeder B disposed on an image forming apparatus A having multiple functions as, for example, a facsimile and a copier. The image forming apparatus A is provided with a platen al for reading a document such as a book; and a platen a 2  disposed adjacent to the platen a 1 ; and an image reading device  20  for being transferred to read the document disposed on the platen a 1  and being stopped under the platen a 2  to read the document transferred by the document feeder B. 
     An upper part of the document feeder B is provided with a document table  2  on which a plurality of documents can be placed in a stacked condition. The documents stacked on the document table  2  are sent by a feeding roller  3 , and the documents are separated sheet by sheet by a supplying roller  3   b  and a separating member  3   c  pressed against the supplying roller  3   b  so as to be supplied to a downstream side. 
     In a middle of a document path  4 , there are disposed a register sensor RS, which detects a leading edge of the document, and a pair of register rollers  5 , and after the document is registered by the register rollers  5 , the document is transferred to a feed roller  6  (transferring means) which faces the platen a 2 . By transferring the document on the platen a 2  at a reading speed by the feed roller  6 , an image of the document is read by the image reading means  20 . At this time, start of reading the image of the document by the image reading means  20  is determined by a document detection by a read sensor LS disposed at an immediate front of the platen a 2 . 
     Next, the document which has passed through the platen a 2  is transferred to switchback/ejection rollers  7 , and ejected by the switchback/ejection rollers  7  onto an ejection tray  8  under the document table  2 . However, in case the document is a double-sided document, the document is returned to the feed roller  6  through a circulation path  4   d  by reverse rotations of the switchback/ejection rollers  7 , and a process of reading a back surface of the document is carried out. Between the feed roller  6  and the switchback/ejection rollers  7 , there are disposed a switching flapper  9 , which guides the document from a switchback/ejection path  4   c  to the circulation path  4   d , and a reverse-ejecting sensor ES, which detects a leading edge and a rear edge of the ejected document. 
     Furthermore, a stamp table  10  and a stamping device  11  are disposed in the switchback/ejection path  4   c . As shown in detail in FIGS. 2 and 3, the stamping device  11  is structured that a solenoid  11   a  is excited to allow an impressing section  11   b  to project in the switchback/ejection path  4   c , so that a mark is impressed at a predetermined position of the document. 
     Incidentally, symbols “12”, “13”, and “14” in FIG. 1 designate pinch rollers which are pressed against a peripheral surface of the feed roller  6 . 
     Also, as driving sources for driving the respective rollers, a supplying motor KM and a transferring motor HM are provided. The supplying motor KM has a driving system such that the supplying motor KM rotates forward to drive the feeding roller  3   a  and the supplying roller  3   b , and the supplying motor KM rotates reversely to drive the register rollers  5 . Also, the transferring motor HM drives the feed roller  6  and the switchback/ejection rollers  7 . 
     FIG. 4 is a block diagram of a control section of the document feeder B according to the present invention, and into a control device CPU, which can be formed of, for example, a micro computer, there are inputted a designated mode signal from a mode selecting button  15 ; a stamp density signal from a density setting button; detected signals from a document sensor GS, a register sensor RS, a second register sensor RS 2 , and the read sensor LS; a document detected signal from the reverse-ejecting sensor ES; and reading speed data VD from the image forming apparatus A. The control device CPU controls the supplying motor KM and the transferring motor HM, which are normally rotated at a reading speed, in accordance with respective process flows and stamp density signals of a non-stamp mode, a stamp mode, an one-side stamp mode, and a two-side stamp mode, which are selected by the mode selecting button  15 . Also, the control device CPU issues an operation instruction to the solenoid  11   a  of the stamping device  11  at proper timing according to the selected non-stamp mode and the stamp mode (one-side stamp mode and two-side stamp mode) so as to actuate the stamping device  11  in accordance with the stamp density signal. 
     Next, operations of the document feeder B according to the embodiment shown in the figures will be explained in detail with regard to FIGS. 5 and 6. FIG. 5 shows a control flow at the non-stamp mode, and when a leading edge of the document sent out from the document table is detected at the register sensor RS, a register pulse in a predetermined period of time is set, so that the document is sent out by the supplying roller  3   b  until the register pulse is counted up. The sent document abuts against the register rollers  5  to be aligned (step S 1  to step S 4 ). 
     In step S 5 , the document is sent toward the feed roller  6  by rotation of the register roller  5 . When the leading edge of the document is detected by the read sensor LS (step  6 ), the document is securely nipped by the feed roller  6  and the pinch roller  13 . Thus, the supplying motor KM is stopped in step S 7 , and after a predetermined pulse is counted up (step S 8 ), the transferring motor HM is stopped (step S 9 ). Accordingly, the document is stopped before the reading position, and thereafter, the document stopped before the reading position is transferred again based on a reading timing signal from the image forming apparatus A at the reading speed so as to pass through the reading position on the platen a 2  (step S 10 ). While the document passes through the reading position on the platen a 2 , the image of the document is read by the image reading means  20 . 
     With transfer of the document on the platen a 2  for a predetermined length after a rear edge of the document is detected by the read sensor LS (step S 11 ), it is recognized that reading the image of the document is completed, so that the transferring motor HM is switched to the highest speed to eject and transfer the document at a high speed in order to reduce time from supplying the document to ejecting the same (step S 12 ). Thereafter, when the rear edge of the document ejected and transferred at the high speed is detected by the reverse-ejecting sensor ES (step S 13 ), paper ejecting pulse is set (step S 14 ). When the paper ejecting pulse is counted up (step S 15 ), it is determined that the document is ejected onto the paper ejecting tray, so that the transferring motor HM is stopped (step S 16 ). 
     Naturally, in case there are subsequent documents on the document table 2, the flow returns to the start, and transferring process and reading process are carried out continuously until the processes for all documents are completed. 
     Next, the control flow in the stamp mode is shown in FIG.  6 . 
     In step S 10  to step S 16  in the stamp mode, processes similar to the steps S 1  to S 7  in the non-stamp mode as described above are carried out. 
     Then, when reading the document image of the document is completed in step S 17 , the transferring motor HM is driven at the highest speed in step S 18 , and the document, image reading of which has been completed, is ejected and transferred at a high speed toward the switchback/ejection rollers  7 . 
     When the rear edge of the document is detected by the reverse-ejecting sensor ES (step S 19 ), in step S 20 , an ejecting and transferring speed of the document (a stamp speed) is determined by a density signal sent based on density information set by the density setting button  16  in a control panel P. Then, the transferring motor HM controls the rotational speed of the switchback/ejection rollers  7  such that the document is ejected and transferred at the determined speed (step S 21 ). 
     The stamping device  11  is actuated to impress a mark on one surface of the document transferred at the stamp speed switched by this series of the operations (step S 22 ). 
     In operations of the stamping device  11 , excitation time or impressing duration for the solenoid  11   a  of the stamping device  11  is such that the solenoid is excited for a period of time selected by the signal sent based on density information set by the density setting button  16  in the control panel, so that the impressing section  11   b  of the stamping device  11  is protruded in the switchback/transfer path  4   c  to impress the mark on the document. 
     Incidentally, the density setting button  16  on the control panel is divided into three steps, and as shown in FIG. 7, it sets the excitation time for the solenoid  11   a  and the stamp speed. In case a signal sent from the control panel P is density  1 , excitation time of 10 msec. and a stamp speed at 136 m/s are set (steps S 20 - 1  and S 20 - 2 ). In case of density  2 , excitation time of 30 msec. and a stamp speed at 45 m/s are set (steps S 20 - 3  and S 20 - 4 ); and in case of density  3 , excitation time of 50 msec. and a stamp speed at 0 m/s are set (stop). 
     By changing the excitation time and the stamp speed as described above, impressing time by the stamping device with respect to the stamp position of the surface of the document can be extended or shortened, so that the density of the mark in the document can be freely adjusted. Namely, if ink of the stamping device is consumed such that the mark impressed on the document becomes lighter, the user can operate the density setting button  16  in the control panel P to extend the impressing time by the stamping device with respect to the stamping position of the surface of the document, resulting in that the impressed mark can be adjusted at a satisfactory density. 
     Also, if the impressing time by the stamping device is extended and the ejecting and transferring speed of the document is reduced, rubbing mark caused by extending the time for impressing the document can be prevented. When the impressing time by the stamping device is shortened and the ejecting and transferring speed of the document is accelerated, time for exchanging the document in the stamp mode can be reduced. 
     After the stamping device  11  impresses the mark on the surface of the document, the ejecting and transferring speed is again switched to the high speed by the transferring motor HM (step S 23 ), and thereafter, the rear edge of the document ejected and transferred at the high speed is detected by the reverse-ejecting sensor ES, so that the paper ejecting pulse is set (step S 24 ). When the paper ejecting pulse is counted up (step S 25 ), it is determined that the document is ejected onto the ejecting tray, so that the transferring motor HM is stopped (step S 26 ). 
     Incidentally, in the present embodiment, when the rear edge of the document is detected by the reverse-ejecting sensor ES, the transferring motor HM is switched to the stamp speed so that the stamping device  11  impresses the mark on the surface of the document. However, when a predetermined period of time has passed after the leading edge of the document is detected, the ejecting and transferring speed may be switched to the stamp speed by controlling the transferring motor HM, so that the stamping device  11  impresses the mark on the surface of the document. 
     Also, the document feeder B of the embodiment shown in the figures can perform the image reading process of the double-sided document, and in case of the double-sided document, a one-side stamp mode or two-side stamp mode can be selected by the mode selecting button  15 . 
     Firstly, in the one-side stamp mode, after the front surface of the document is read, when the rear edge of the document is detected by the reverse-ejecting sensor ES, the switching flapper  9  is switched by the signal from the reverse-ejecting sensor ES, and at the same time, the switchback/ejection rollers  7  are reversely rotated. Thus, the document, reading of the front surface of which has been completed, is returned to the platen a 2  by the feed roller  6  in the condition that the back surface of the document faces down, and the back surface of the document is read by the image reading means  20 . The document, reading of the back surface of which has been completed, is returned to the feed roller  6  by the detected signal of the reverse-ejecting sensor ES again. However, at this time, reading the document is not performed, and in the condition that the front surface of the document faces down, the stamping device  11  impresses the mark on the front surface of the document, and then the document is ejected onto the ejection tray  8  by the switchback/ejection rollers  7 . 
     In case of the two-side stamp mode, after the front surface of the document is read, the rear edge of the document is detected by the reverse-ejecting sensor ES, so that the stamping document  11  is actuated to impress the mark at a portion near a rear edge portion of the front surface of the document. Then, the switching flapper  9  is switched by the signal from the reverse-ejecting sensor ES, and at the same time, the switchback/ejection rollers  7  are rotated reversely. Therefore, the document, reading of the front surface of which has been completed, is returned to the platen a 2  by the feed roller  6  in the condition that the back surface of the document faces down, and the back surface of the document is read by the image reading means  20 . With respect to a portion near a rear edge portion of the back surface of the document, reading of the back surface of which has been completed, a stamp process is carried out while the document passes through the stamping device  11 , and the document is ejected onto the ejection tray  8  by the switchback/ejection rollers  7 . 
     Although the stamp speed and the exciting time for the excitation solenoid by the stamping device can be freely switched on the panel by the user in the aforementioned embodiment, they may be switched in accordance with a number of impressing times by the stamping device. 
     In this case, one is added to an impressing counter after impressing the mark on the document is completed, and when reaching the predetermined number of times, the stamp speed and exciting time for the excitation solenoid by the stamping device can be automatically switched. Namely, as shown in FIG. 8, in case impressing times are 5,500 times or less according to a counted value by a stamp counter, excitation time is set at 10 msec. and the stamp speed is set at 136 m/s (step S 20 - 9 , step S 20 - 10 ); in case the impressing times are 5,501 times to 5,950 times, the excitation time is set at 30 msec. and stamp speed is set at 45 m/s live (step S 20 - 11 , S 20 - 12 ); and in case the impressing times are 5,950 times to 6,000 times, the excitation time is set at 50 msec., and the stamp speed is set at 0 m/s (stop). Also, in case of over 6,000 times, exchanging the stamping device is displayed (step S 20 - 15 ). 
     Also, although exciting time for the excitation solenoid by the stamping device is switched in the aforementioned embodiment, the exciting time for the excitation solenoid by the stamping device may be uniform, and pressing force with respect to the document by the stamping device may be switched. The pressing force by the stamping device can be changed by controlling excitation current value of the solenoid, and in this case, it can be set such that: 
     in case of the density  1 , the excitation current is 0.25 Å and the stamp speed is 136 m/s: 
     in case of the density  2 , the excitation current is 0.35 Å and the stamp speed is 45 m/s: and 
     case of the density  3 , the excitation current is 0.50 Å and the stamp speed is 0 m/s. 
     According to the present embodiment, the set time for impressing the mark on the document or pressing force by the stamping device is switched, and at the same time, the ejecting and transferring speed of the document at the time of operating the stamping device is switched. Therefore, the density of a mark impressed on the document can be adjusted.