Abstract:
In a printer-copiers system of an office area (“OA”) network, an automatic document feeder (ADF) is used in an image output device which selectively outputs the image read from the document or received from an external device (for printing or facsimile transmission). If some trouble occurs during the reading of a document and disables the read operation, the conventional image output device is brought into a substantially non-operating state (system down), when viewed from the external device, and remains therein till the trouble is removed and the read operation is enabled. Unless the user promptly takes the proper measures, not only the copy job but also the print job stagnates. It is therefore an object of the present invention to minimize the duration of a period during which the read operation is disabled by promptly canceling the hang-up of the processor for controlling the reading of the document.

Description:
[0001]    This application is based on application No. 09-298135 filed Oct. 30, 1997, in Japan, the content of which is hereby incorporated be reference. 
     
    
     
       TECHNICAL FIELD OF THE INVENTION  
         [0002]    The present invention relates to an image output device for print-outputting (printing) or transmitting image information read from a document and image data received from an external device, which is applicable to a printer-copier, a printer with an image reader connected thereto or integrated therewith, a facsimile, and the like.  
         BACKGROUND OF THE INVENTION  
         [0003]    In recent years, printer-copiers (including a combination model also functioning as a facsimile) have been used in an office area (“OA”) network. On the other hand, a print system composed of a printer with an image reader connected thereto has also been used in practice because of its usability as a copier in which an image read from an original (document) is transferred directly to the printer and printed without the intervention of a computer. If an automatic document feeder (ADF) is used in such an image output device which selectively outputs the image read from the document or received from an external device (for printing or facsimile transmission), the operation of copying or transmitting a large number of documents can be performed with improved efficiency as in a commonly used copier.  
           [0004]    In a conventional image output device, once a copy job operation is initiated in which an image is read from a placed document and outputted (for printing or transmission), the output of image data received from an external device is disabled till the completion of the copy job operation. Even during the execution of the copy job operation, however, the receipt of a print job in which an image is outputted from the external device, i.e., the process of receiving and temporarily storing data is performed.  
         SUMMARY OF THE INVENTION  
         [0005]    If some trouble occurs during the reading of a document and disables the read operation, the conventional image output device is brought into a substantially non-operating state (system down), when viewed from the external device, and remains therein till the trouble is removed and the read operation is enabled. Unless the user promptly takes the proper measures, not only the copy job but also the print job stagnates. One type of potential trouble is the hang-up of a processor for controlling the image reader. In case of hang-up, the user is required to press a reset switch provided in the image reader. Although the reset operation is supposed to immediately cancel the hang-up of the processor and enable the read operation, the operation of resetting printer hardware or an instruction to reset printer software from the external device to the printer occasionally causes switching to an operational mode in which the print job is executed, so that the reading function is not used afterwards. Even when the processor is hung up, during a period which the read operation is not performed, an instruction to execute the copy job is not received after the hang-up of the processor so that the reading function remains unusable unless the reset operation is performed.  
           [0006]    It is therefore an object of the present invention to minimize the duration of a period during which the read operation is disabled by promptly canceling the hang-up of the processor for controlling the reading of the document. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 shows the structure of a principal portion of a network according to the present invention;  
         [0008]    [0008]FIG. 2 is a functional block diagram of an image output device according to the present invention;  
         [0009]    [0009]FIG. 3 is a main flow chart illustrating a control operation on the printer side;  
         [0010]    [0010]FIG. 4 is a flow chart illustrating the reading-function diagnosing subroutine; and  
         [0011]    [0011]FIG. 5 is a flow chart illustrating the mode switching subroutine. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0012]    [0012]FIG. 1 shows the structure of a principal portion of a network  100  according to the present invention.  
         [0013]    The network  100  is a LAN in which a plurality of computers  41  to  44  use a printer  20  in common. The printer  20  is connected to a cable  50  via a network interface card (NIC)  26 . The computer  41 , which is among the plurality of computers  41  to  44 , functions as a print server. The network  100  may also adopt a form in which a parallel port  25  is used to provide a connection between the printer  20  and the computer  41  so that the printer  20  is connected to the cable  50  via the computer  41 .  
         [0014]    An image reader  10  is connected to the printer  20  via a port  24  in a predetermined form. The image reader  10  is flat-type image inputting means which performs a line-by-line scanning operation with respect to the image of a document positioned on a document glass. The image reader  10  has an ADF (automatic document feeder)  30 , also serving as a document cover, attached thereto. The document placed on a document feed tray  30   a  of the ADF  30  is fed onto the document glass of the image reader  10  and discharged onto a document discharge tray  30   b  after the scanning operation is completed. If an anterior side of the ADF  30  is raised in photocopying, e.g., a book, the whole ADF  30  rotates about the lower edge of the posterior side thereof serving as a spindle, so that the document glass of the image reader  10  is exposed. This indicates that the document may also be placed directly on the document glass.  
         [0015]    In the present embodiment, the image reader  10 , the ADF  30 , and the printer  20  constitute an image output device  1  according to the present invention. The image output device  1  may be formed into a system in which a variety of separate devices are connected with cables or into a combination model into which individual functional units are integrated.  
         [0016]    [0016]FIG. 2 is a functional block diagram of the image output device  1  according to the present invention.  
         [0017]    The image reader  10  has a scanner  12  for scanning the image of the document and a buffer  13  for temporarily storing image data obtained as a result of scanning, which are controlled by a CPU as a control system of the present invention. The CPU  11  receives an ON-OFF signal S 16  from a copy button  16  and a detect signal S 31  from a jam sensor  31  provided in the ADF  30 . When the copy button  16  is turned ON, the CPU  11  outputs a print request signal S 10  to the printer  20  and initiates scanning. When the printer side is in the acceptable state, image data D 10  obtained as a result of scanning is transferred from the image memory  13  to the printer  20 .  
         [0018]    In the printer  20 , the image data D 10  from the image reader  10 , a print data D 41  from the computer  41  as the external device, and print data D 45  inputted to the parallel port is inputted to a controller  21  having a data processor. The print data D 41 , D 45  is image information represented in a specified page description language. A print engine  22  receives image information properly processed by the controller  21 . At this stage, the print data D 41 , D 45  is subjected to command analysis and bit mapping. Input data from the outside is received (i.e., loading of the print job) not only during standby but also during the reading of the document (during the execution of the copy job). In the case of printing the image data D 10  from the image reader  10 , the image output device I performs a copy operation. In the case of printing the print data D 41 , D 45 , the image output device  1  performs a print operation.  
         [0019]    The CPU  11  of the image reader  10  and the controller  21  of the printer  20  communicate with each other to process the print job and the copy job. For example, if a jam occurs during the copy operation to disable the read operation, the CPU  11  notifies the controller  21  of the disabled state. If the read operation is not performed properly, the controller  21  does not wait for the recovery of the reading function but frees the print engine  22  to the print job at the appropriate time, thereby preventing the stagnation of the print job. If there is no normal response from the CPU  11 , the controller  21  judges that the CPU  11  is hung up, outputs a reset signal S 20  instructing the CPU  11  to restart the control program, and normalizes the control of the image reader  10 , which is a function exclusive to the present invention.  
         [0020]    [0020]FIG. 3 is a main flow chart illustrating a control operation on the printer side.  
         [0021]    When the control program is initiated upon turning ON of the power or in response to the reset instruction, the controller  21  initializes various registers by clearing a specified memory and sets a default mode (# 1 ). Subsequently, the controller  21  starts an internal timer defining a control routine time (# 2 ). Thereafter, the controller  21  starts each of a reading-function diagnosing subroutine (# 3 ), a mode switching subroutine (# 4 ), a print control subroutine (# 5 ), and an other process subroutine (# 6 ). After the other process subroutine is completed, the whole process waits for the completion of the internal timer, returns to the step # 2 , and repeats the steps # 2  to # 7 . The reset timer is timed by counting the number of executions of the routine, which will be described later.  
         [0022]    [0022]FIG. 4 is a flow chart illustrating the reading-function diagnosing subroutine.  
         [0023]    First, a flag F 1  indicative of the image reader  10  in an abnormal state is checked (# 301 ). If the flag F 1  is OFF, it is judged whether communications between the image reader  10  and the CPU  11  are normal or not, i.e., whether there is a normal response or not (# 302 ). When the communications are normal, it is subsequently judged whether there is a notification on abnormal reading from the CPU  11  or not (# 303 ). If the function of reading the document is properly performed, the whole process immediately returns to the main routine. If there is no normal response from the CPU  11  due to the hang-up of the CPU  11  or the like, or if abnormal reading such as jam is reported, the flag F 1  is set (# 304 ) and a reset signal S 20  is outputted to the CPU  11  (# 305 ). Then, the reset timer for continually outputting the reset signal S 20  over a given period is set (# 306 ), whereby the whole process returns to the main routine.  
         [0024]    On the other hand, if it is judged that the flag F 1  is already ON in the step # 301 , the state of the reset timer is checked (# 307 , # 308 ). If the timing of the reset timer is ongoing, the whole process returns. If the timing of the reset timer is completed, the output of the reset signal S 20  is completed (# 309 ) and the operating state of the image reader  10  is checked again (# 310 , # 311 ). If such trouble as hang-up or jam is removed and the image reader  10  returns to the normal operating state, the flag F 1  is turned OFF (# 312 ). If it is judged that the reset timer has not been set in the step # 307 , the whole process proceeds to the step # 310  where the operating state of the image reader  10  is checked.  
         [0025]    In the main subroutine, the operating state of the image reader  10  is checked after the timing of the reset timer is completed. Since a certain rise time should elapse from the time when the control program is restarted in response to the reset signal S 20  till the standby state is reached, the arrangement is for allowing the rise time to elapse. The arrangement prevents a collision between paper for the copy job and paper for the print job on a paper discharge tray resulting from the interruption of the print job during the rise time.  
         [0026]    [0026]FIG. 5 is a flow chart illustrating the mode switching subroutine.  
         [0027]    First, the flag F 1  is checked (# 401 ). If the flag F 1  is OFF and the image reader  10  is in the normal operating state, a copy mode is set provided that there is a copy request from the image reader  10  and printing for the print job is not ongoing (# 402  to # 404 ).  
         [0028]    On the other hand, a print mode is set if the flag F 1  is ON (# 401 , # 405 ). In other words, the print engine  22  is freed to the print job if the image reader  10  is in an abnormal operating state, which enables the print operation and prevents the stagnation of the print job even when the copy operation is disabled.  
         [0029]    Even when the flag F 1  is ON, the print mode is set if there is no copy request (# 402 , # 405 ), which indicates that the normal mode is the print mode. Even when there is a copy request, the print mode is maintained if printing is ongoing(# 403 , # 405 ) so that the print mode is switched to the copy mode at the breakpoint of the print job (on a job-by-job or page-by-page basis).  
         [0030]    According to the foregoing embodiment, it is no longer necessary for the user to manually cancel the hang-up of the CPU  11 . Since the reset timer allows the period during which the reset signal S 20  is outputted to be sufficiently elongated, the CPU  11  can reliably recognize the reset instruction and restart the control program. When trouble occurs in the ADF  30  or image reader  10 , the print mode is set so that the accumulation of print jobs during the recovery of the reading function is prevented.  
         [0031]    In the foregoing embodiment, the image output device  1  may be a printer-copier into which the image reader  10  and the printer  20  are integrated. It is also possible to notify the printer  20  of not only a jam but also such trouble as a breakdown of the scanner  12  as a functional disorder. The present invention is also applicable to a facsimile for outputting an image read from a document or an image from an external device, such as a computer, to a public telephone network.  
       EFFECT OF THE INVENTION  
       [0032]    The duration of a period during which a read operation is disabled can be minimized by promptly canceling the hang-up of the processor for controlling the reading of a document.  
         [0033]    Even when abnormal reading occurs, the operational mode at the occurrence of abnormal reading is held for a given period of time, which prevents excessive impairment of usability in reading an image from a document and outputting the read image.  
         [0034]    Of course, it should be understood that a wide range of modifications can be made to the exemplary embodiments described above. It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, which are intended to define the scope of this invention.