Abstract:
An image forming apparatus is provided which is capable of storing image data regardless of remaining free area of a memory associated with a specified function. The digital image forming apparatus comprises a facsimile memory for storing transmission/reception data by a memory transmission/reception function of a facsimile, a copying memory for storing copying data by a copying/printing function or externally inputted data, and a compression/expansion converting section which converts transmission/reception data stored in the facsimile memory by the memory transmission/reception function into data suitable for communication via a communication line, wherein a CPU working as storage control means is disposed which, when storing data by one function of a plurality of functions into a memory associated with the function, stores the data into a memory associated with another function in the case where all the data cannot be stored into the associated memory.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an image forming apparatus comprising a facsimile memory for storing transmission/reception data by a memory transmission/reception function of a facsimile and a copying memory for storing copying data or externally inputted data by a copying/printing function. 
   2. Description of the Related Art 
   In a conventional digital image forming apparatus which is called a digital composite machine and provided with a fax mode and a copy mode (copying function or printing function), an operation panel for setting conditions of the fax and copy modes is integrated with a control function thereof. 
   However, although the control function is integrated with the operation panel, memories associated with the respective functions individually work. Therefore, in the fax mode, when a memory for memory reception becomes full, a reception state is put into a busy state, or data not yet outputted is erased because reception data in the memory is overwritten. Such a phenomenon frequently happens particularly when recording sheets such as sheets of paper in a paper-feed cassette or rolls of paper run out in the nighttime or when a supply item such as toner is replaced. 
   Further, in the copy mode, a technique utilizing memory copying for increasing the speed of reading documents in image processing is used, however, when a memory for document information becomes full, reading of the following document is stopped, and therefore the document reading speed cannot be increased. 
   Japanese Unexamined Patent Publication JP-A 10-243175 (1998) discloses a technique of checking the remaining free area of a memory and controlling so as to allow a copy operation when a document size read in the following operation is within the remaining free area of the memory, whereas so as not to accept a reading request when the document size is larger. 
   As mentioned above, the conventional digital image forming apparatus checks the remaining free area of a memory and controls so as to allow a copy operation when a document size read in the following operation is within the remaining free area of the memory, whereas so as not to accept a reading request when the document size is larger. Therefore, the apparatus raises a problem such that when a memory has only a little or no free area, the following operation can not be carried out, or data not yet outputted is erased because of overwriting. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to provide an image forming apparatus which is capable of storing data of an image regardless of remaining free area of memories associated with functions, respectively. 
   The invention provides an image forming apparatus comprising memories associated with two or more functions, respectively, for storing data relating to the corresponding function, the image forming apparatus further comprising storage control means for controlling storage of data into the memories so that in the case where data relating to one of the functions should be stored in a memory associated with the function while all the data relating to the function cannot be stored in the memory associated with the function, at least part of the data relating to the function is stored in a memory associated with another function. 
   According to the invention, even in the case where all data relating to a function in operation cannot be stored in a memory associated with the function, at least part of the data is stored in a memory associated with another function. Therefore, it is possible to continuously operate the function in operation without suspending. 
   In the image forming apparatus of the invention it is preferable that two of the memories associated with two or more functions, respectively, are a facsimile memory for storing data of an image transmitted/received by a memory transmission/reception function of a facsimile and a copying memory for storing data of an image to be copied by a copying/printing function or data of an externally inputted image. 
   According to the invention, since the amount of data stored in the copying memory is large in the daytime when the copying/printing function is often used and the amount of data stored in the facsimile memory is large in the nighttime when output sheets are likely to be exhausted, it is possible to share such memories used in different conditions and thereby operate the respective functions with small capacity of memories without suspending the functions. 
   In the image forming apparatus of the invention it is preferable that the image forming apparatus further comprises a compression/expansion conversion section for converting data to be stored in the facsimile memory into data suitable for communication via a communication line, and when storing data of an image relating to the copying/printing function and including half tone, into the facsimile memory, the storage control means controls storage of the data of the image so that the data is stored in the facsimile memory without conversion of the data by the compression/expansion converting section. 
   According to the invention, data of the image relating to the copying/printing function and including half tone is stored in the facsimile memory without being subjected to compression conversion by the compression/expansion converting section. Therefore, it is possible to execute copying an output of data of an image including half tone with fidelity to the original data. 
   In the image forming apparatus of the invention it is preferable that the image forming apparatus further comprises a compression/expansion converting section for converting data to be stored in the facsimile memory into data suitable for communication via a communication line, and when storing data of an image relating to the copying/printing function and externally inputted, into the facsimile memory, the storage control means controls storage of the data so that the data is stored into the facsimile memory after compression conversion of the data by the compression/expansion converting section. 
   According to the invention, externally inputted data composed of text data (binary-value data) without halftone data is subjected to compression conversion by the compression/expansion converting section and stored in the facsimile memory. Therefore, it is possible to store a large amount of externally inputted data in the facsimile memory. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other and further objects, features, and advantages of the invention will be more explicit from the following detailed description taken with reference to the drawings wherein: 
       FIG. 1  is a sectional view showing an embodiment of a digital composite machine, which is an image forming apparatus of the present invention; 
       FIG. 2  is a block diagram showing a control block of the digital composite machine of  FIG. 1 ; 
       FIG. 3  is an explanation view showing a flow of image data and control signals in the digital composite machine of the invention; 
       FIG. 4  is a flow chart explaining a copy operation in the digital composite machine of the invention; and 
       FIG. 5  is a flow chart explaining a fax receiving operation in the digital composite machine of the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Now referring to the drawings, preferred embodiments of the invention are described below. 
   An embodiment of a digital composite machine provided with a fax mode and a copy mode (copying mode, printing mode), which is an image forming apparatus of the present invention, will be explained referring to  FIGS. 1  to  5 . 
     FIG. 1  is a sectional view showing the entire mechanical construction of a digital composite machine  30  of the embodiment. As shown in  FIG. 1 , the digital composite machine  30  is composed of a scanner section  31  and a laser recording section  32 . 
   The scanner section  31  is composed of a document glass  35  made of transparent glass, a recirculating automatic document feeder  36  (referred to as an RADF hereafter) for automatically supplying and conveying a document onto the document glass  35 , and a document image reading unit for operating and reading an image of a document put on the document glass  35 , that is, a scanner unit  40 . 
   A document image read by the scanner section  31  is sent as image data to an image processing section  1  mentioned later, where the image data is subjected to predetermined image processing. 
   The RADF  36  is a device which automatically feeds a plurality of documents set on a specified document tray at a time, one by one onto the document glass  35  of the scanner unit  40 . Further, in order to cause the scanner unit  40  to read one side or both sides of a document in response to a selection of the user, the RADF  36  is composed of a conveying path for a one-side document, a conveying path for a both-side document, conveying path switching means, and so on. 
   The scanner unit  40  is composed of a lamp reflector assembly  41  which exposes the surface of a document, a first scanning unit  40   a  formed by a first reflection mirror  42   a  for guiding a reflected light image from the document to a photoelectric conversion device  44  embodied by a CCD or the like, a second scanning unit  40   b  formed by second and third reflection mirrors  42   b ,  42   c  for guiding the reflected light image from the first scanning unit  40   a  to the photoelectric conversion device  44 , an optical lens member  43  for forming an image of the reflected light image onto the photoelectric conversion device  44 , and the photoelectric conversion device  44  which converts the formed image of the reflected light image into electric image signals. 
   The scanner section  31  is constructed so as to, while documents to be read are sequentially put onto the document glass  35  by a related operation of the RADF  36  and the scanner unit  40 , move the scanner unit  40  along the lower surface of the document glass  35  and read images of the documents. Image data obtained by reading an image of a document by the scanner unit  40  is sent to the image processing section  1  mentioned later and subjected to a variety of processes. After that, the image data is supplied to a laser writing unit  46  of the laser recording section  32 , and reproduced as a visible image onto a photoconductor drum  48  in an electrophotographic process. Then, the image is transferred and formed onto a recording sheet. 
   The laser recording section  32  includes a paper-sheet housing/conveying section  50 , the laser writing unit  46 , and an electrophotographic process section  47  for forming an image. The paper-sheet housing/conveying section  50  has a first cassette  51 , a second cassette  52 , a third cassette  53  and a multiple manual feed tray  54 , and moreover has a double-side copying unit  55  for recording an image onto the rear side of a paper sheet with an image recorded on one side sent out of one of the cassettes or the tray. 
   In the respective cassettes of the paper-sheet housing/conveying section  50 , batches of paper sheets are housed for each size. When the user selects one of the cassettes which houses paper sheets of desirable size, the paper sheets are sent out of the cassette one by one from the top of the batch thereof, and sequentially conveyed toward an image forming section of the laser recording section  32  via a conveying path  59 . 
   The laser writing unit  46  has a semiconductor laser which emits laser light according to image data from a memory, a polygon mirror which deflects the laser light at an equal velocity, an f-θ lens which corrects so as to be deflected at an equal velocity, and so on. 
   The electrophotographic process section  47  is composed of a charging device, a developing device, a transferring device, a separating device, a cleaning device, a discharging device and a fixing device  49 , which are placed around the photoconductor drum  48  in accordance with well-known configurations. A sheet carrying-out conveying path is placed on the downstream side in the direction of conveying a paper sheet onto which an image should be formed from the fixing device  49 . The sheet carrying-out conveying path is branched to a conveying path  57  which leads to an after-process device  34  and a conveying path  56  which leads to a double-side copying unit  55 . 
   In the laser writing unit  46  and the electrophotographic process section  47 , image data read out of an image memory is formed as an electrostatic latent image onto the surface of the photoconductor drum  48  by scanning laser light by the laser writing unit  46 , and a toner image made to be a visible image by toner is electrostatically transferred and fixed onto the surface of a recording sheet conveyed from a multistage paper feeding unit  33 . 
   The recording sheet with an image formed thereon in this manner is selectively conveyed from the fixing device  49  to the after-process device  34  via the conveying path  57  or to the double-side copying unit  55  via the conveying path  56 . The after-process device  34 , in which a first discharge tray  341  and a second discharge tray  342  are vertically placed on the left side of the apparatus, receives a recording sheet with an image recorded thereon in the digital composite machine  30  from the conveying path  57 . 
     FIG. 2  is an electric configuration block diagram showing a variety of units composing the digital composite machine  30  of  FIG. 1 , the image processing section, and so on. This is a view showing a state of controlling an operation by a main central processing unit (main CPU)  401  placed substantially in the center through coordination with sub central processing units (sub CPUs) mounted for each unit section. 
   It is apparent from this configuration block diagram that the digital composite machine is mainly composed of an operation panel board  100  which locates substantially at the upper right on the drawing and controls an operation panel  103 , a machine control board  200  which locates substantially at the upper left on the drawing and controls the respective unit sections constructing the digital composite machine  30 , a CCD board  300  which locates substantially at the lower left on the drawing and electrically reads a document image to convert it into electronic data, a main image processing board  400  which locates substantially in the center on the drawing and subjects the document image converted into electronic data by the CCD board  300  to predetermined image processing, a sub image processing board  500  which further subjects the image information processed by the main image processing board  400  to predetermined image processing, a group of other expansion boards  600  (a printer board  601 , a function expansion board  602 , a facsimile board  603 ) which locate substantially at the lower right on the drawing and are connected with the image processing board  500  via an interface, and so on. 
   In the following, what is controlled by each board will be explained. 
   Operation Panel Board  100   
   The operation panel board  100 , which is controlled basically by a sub CPU  101 , controls a display screen of an LCD display  104  placed on the operation panel  103 , operation input through a group of operation keys  105  for inputting directions regarding a variety of modes, and so on. Further, a memory  102  for storing various control information for the operation panel such as data inputted through the group of operation keys  105  and information displayed on the LCD screen  104  is disposed. 
   In this configuration, the sub CPU  101  performs control data communication with the main CPU  401  to give directions on the operation of the digital composite machine  30 . Further, the main CPU  401  transfers a control signal showing an operation state of the digital composite machine  30  to the sub CPU  101 , whereby the LCD screen  104  of the operation panel  103  displays a current operation state of the apparatus for the user. 
   Machine Control Board  200   
   The machine control board  200 , which is entirely controlled by the sub CPU  201 , controls automatic document feeders  36  such as an ADF and an RADF, a scanner section  31  which reads a development image, an electrophotographic process section  47  which reproduces image information as an image, a paper-sheet housing/conveying section  206  which sequentially conveys sheets of paper on which images should be recorded from cassettes or a tray toward a process section  205 , a double-side copying unit  55  which reverses recording sheets with images recorded thereon and conveys the recording sheets in reverse so that images are formed on both the sides of the recording sheets, a finisher  34  which performs an after-process such as stapling the recording sheets with images recorded thereon, and so on. 
   CCD Board  300   
   The CCD board  300  is composed of a CCD  301  including an photoelectric conversion device  40  for electrically reading a document image, a circuit (CCD gate array)  302  which drives the CCD  301 , an analog circuit  303  which adjusts the gain of analog data outputted from the CCD  301 , an A/D converter  304  which converts analog outputs of the CCD  301  into digital signals and outputs as electronic data, and so on. The CCD board is controlled by the main CPU  401 . 
   Main Image Processing Board  400   
   The main image processing board  400  is controlled by the main CPU  401 . The main image processing board is composed of a multiple-value image processing section  402  which, based on electronic data of a document image sent from the CCD board  300 , so as to express the contrast of the image in a desirable state, subjects the multiple-value image data to shading correction, density correction, area separation, filter process, MTF correction, resolution conversion, electronic zoom (scaling process), gamma correction and the like, a memory  403  for storing processed image data or various control information on control of the procedure of processes, a laser control  404  which controls so as to transfer data toward the laser writing unit  46  in order to reproduce an image with processed image information, and so on. 
   Sub Image Processing Board  500   
   The sub image processing board  500  is connected with the main image processing board  400  by connectors  505 ,  405 . The sub image processing board is composed of a binary-value image processing section  501  controlled by the main CPU  401  on the main image processing board  400 , a gate array  503  which controls a hard disk for storing binary-value image information subjected to image processing or control information on processes and producing a plurality of copies by repeatedly reading out a plurality of document images by a desirable copy number, a gate array  504  which controls a SCSI serving as an external interface, and so on. 
   Further, the above-mentioned binary-value image processing section  501  is composed of a processing section which converts multiple-value image information into a binary-value image, a processing section which rotates an image, a binary-value scaling (zoom) processing section which subjects a binary-value image to a scaling process, and so on. The binary-value image processing section further includes a fax interface so as to be capable of transmitting/receiving a fax image via communication means. 
   Expansion Board  600   
   The expansion boards  600  are a printer board  601  which enables data sent from a personal computer and the like to be outputted from a printer section of the digital composite machine in a printing mode, a function expansion board  602  for expanding an editing function of the digital composite machine and effectively using the characteristics of the digital composite machine, a facsimile board  603  which enables a document image read from the scanner section of the digital composite machine to be transmitted to the counterpart and enables image information sent from the counterpart to be outputted from the printer section of the digital composite machine, or the like. 
   In the following, regarding the image processing apparatus of the digital composite machine, image data processing in a fax mode and the flow of image data will be explained in more detail. 
   Fax Mode 
   The fax mode includes a process for transmission of a document to the counterpart and a process for reception of a document from the counterpart. 
   First, transmission of a document to the counterpart will be explained. Transmission documents set on a predetermined position of the RADF  36  of the digital composite machine  30  are sequentially supplied one by one onto the document glass  35  of the scanner unit  40 , sequentially read by the configuration of the scanner unit  40  of images of transmission documents as explained before, and transferred to the main image processing board  400  as 8 bits of electronic data. The 8 bits of electronic data transferred to the main image processing board  400  is subjected to predetermined processing on the multiple-value image processing section  402  as 8 bits of electronic image data. 
   Then, the 8 bits of electronic image data subjected to processing are sent from the connector  405  on the side of the main image processing board  400  to the sub image processing board  500  via the connector  505  on the side of the sub image processing board  500 . In a multiple-to-binary value conversion section of the binary-value image processing section  501 , the 8 bits of electronic image data is subjected to processes such as error diffusion and converted from 8 bits of electronic image data into 2 bits of electronic image data. 
   Here, the reason for converting 8 bits of electronic image data into 2 bits of electronic image data together with executing processes such as error diffusion is that there is a problem in image quality in the case of only executing multiple-to-binary value conversion and therefore it is considered to reduce degradation of image quality. 
   In this way, transmission document image data converted into a binary-value image is compressed in a specified form and stored in a memory  502  on the sub-image processing board. Then, when a transmission procedure with the counterpart is performed and a transmittable state is ensured, transmission document image data compressed in a specified form and read out of the memory  502  is transferred to the facsimile board  603 , subjected to necessary processes such as change of a compression form on the facsimile board  603 , and sequentially transmitted to the counterpart via a communication line. 
   Next, the processing of a document image transmitted from the counterpart will be explained. 
   When a document image is transmitted from the counterpart via a communication line, image data transmitted from the counterpart is received while a communication procedure on the facsimile board  603  is performed, the image data compressed in a specified form is sent from a fax interface disposed to the binary-value image processing section  501  of the sub image processing board  500  to the binary-value image processing section  501 , and the transmitted document image is reproduced as a page image by a compress/expansion processing section or the like. 
   Then, the document image reproduced as an image by page is transferred to the main image processing board  400  and subjected to gamma correction, and the writing of an image is controlled by the laser control  404  so as to reproduce an image by the LSU  406 . 
   As is evident from the above configuration, a processing section-for subjecting image information to a predetermined process is mainly divided into the main image processing board  400  which processes a document image read and inputted from the scanner section  31  as multiple-value image information, and the sub image processing board  500  which-subjects the document image information processed as multiple-value image information on the main image processing board  400  to a predetermined process such as a binary-value process and subjects image information sent from an equipment connected via an external interface to a predetermined process, thereafter transferring to the multi-value image processing section (the main image processing board  400 ). Further, the image processing section  1  which actually processes image data in  FIG. 1  is divided into the multiple-value image processing section  402  on the main image processing board  400  and the binary-value image processing section  501  on the sub image processing board in FIG.  2 . 
   Further, the main image processing board  400  includes the laser control  404  for controlling the writing of image information of the laser writing unit  46 , in order to reproduce an image from the laser writing unit  46  onto the photoconductor drum  48  of the electrophotographic process. 
   With this configuration, it is possible to reproduce a document image read and inputted from the scanner section  31  as a copy image from the laser recording section  32  without impairing image characteristics which the document has as a multiple-value image. For example, in the case of outputting a large amount of documents at high speed by using an electronic RDH function, the sub image processing board  500 , the hard disk  503 , and so on are used. 
   Furthermore, in so far as the processing, outputting and faxing of image information from external equipment such as a fax or a printer are concerned, it is possible to apply an appropriate process to image information in accordance with a digital feature function given to the digital composite machine  30 , for example, a binary-value process to a transmission document subjected to a multiple-value image process and a transmission document whose document image characteristics are kept. 
   Still further, separate placement of components concerning image processing on a plurality of boards makes it possible to prepare a variety of digital composite machines  30  and install a digital image forming apparatus in response to a request from the user. Moreover, after installment, it is possible to roll out systems with ease in response to a request from the user. 
   Next, since the main CPU  401  placed on the main image processing board  400  also controls the sub image processing board  500  in the above configuration, the flow of all image data continuously processed in the respective processing sections on the main and sub image processing boards is controlled, and the flow of data and process also becomes smooth. Therefore, image data would not be lost. 
   Up to this point, the scanner section  31  mounted in the digital composite machine  30 , or the image processing section  700  which processes image data inputted from the external interface  600  has been explained. 
     FIG. 3  is a block diagram showing sections which relate to a facsimile function and a copy function of the embodiment extracted from the configuration of the above-mentioned digital composite machine  30  of FIG.  2 . 
   Sections which relate to a facsimile mechanism and a copy mechanism in the digital composite machine  30 , in terms of function, includes the scanner section  31 , the CPU  401  of the main image processing board, the image processing section  1 , an image data switching section  2 , an LSU control section  3 , an image forming processing section  4 , a memory for copying  5 , a fax memory  6 , a compression/expansion converting section  7 , a bypass line  8  and a modem section  9 . 
   The image processing section  1  of  FIG. 3  corresponds to the multiple-value image processing section  402  and the binary-value image processing section  501  of FIG.  2 . The image data switching section  2  of  FIG. 3  corresponds to one function of the CPU  401  of the main image processing board of FIG.  2 . The LSU control section  3  of  FIG. 3  corresponds to the laser control  404  of FIG.  2 . The image forming processing section  4  of  FIG. 3  corresponds to the laser recording section  32  of  FIG. 1  including the LSU of FIG.  2 . The memory for copying  5  and the fax memory  6  of  FIG. 3  correspond to memory areas in the memory  502  on the sub image processing board of  FIG. 2 , respectively. The compression/expansion converting section  7  of  FIG. 3  corresponds to one function in the binary-value image processing section  501  of FIG.  2 . The modem section  9  of  FIG. 3  corresponds to the whole fax board of FIG.  2 . The CPU  401  of the main image processing board also works as a storage control section for controlling data storage into the memory for copying  5  and the fax memory  6 . 
   In a general copy mode, image data read by the scanner section  31  is subjected to image processing in the image processing section  1  and thereafter supplied from the image data switching section  2  to the image forming processing section  4  via the LSU control section  3 . Together with an image forming process thereof, the reading of the image data is performed. 
   On the other hand, in a memory copy mode, after being subjected to an image forming process in the image processing section  1 , image data read by the scanner section  31  is once held into the memory for copying  5  from the image data switching section  2 , sequentially read out in response to the image forming speed, and supplied from the image data switching section  2  to the image forming processing section  4  via the LSU control section  3 . In this manner, the reading of image data is performed in advance independently of the image forming process. Therefore, it is possible to increase the reading speed. 
   In this memory copy-mode, when the memory for copying  5  becomes full, image data is accumulated into the fax memory  6 . Here, in the,case of being set so as to place emphasis on capacity, the image data switching section  2  supplies image data to the fax memory  6  via the compression/expansion converting section  7  which compresses image data into fax data, thereby performing accumulation by a less memory capacity with respect to one unit of image data. 
   On the contrary, in the case of being set so as to place emphasis on image quality, the image data switching section  2  supplies image data without compression directly to the fax memory  6  via the bypass line  8  which bypasses the compression/expansion converting section  7 , thereby performing accumulation by the same image quality as image data accumulated in the memory for copying  5 . 
   Further, in a fax transmission mode, after being subjected to image processing in the image processing section  1 , image data read by the scanner section  31  is supplied from the image data switching section  2  to the compression/expansion converting section  7  to be compressed. After that, the image data is transmitted from the modem section  9  to a line via the fax memory  6 . In a direct transmission mode, the reading of image data is performed together with transmission of image data. On the contrary, in a memory transmission mode, the reading of image data is performed in advance independently of transmission, and image data of the difference from a transmission output is accumulated in the fax memory  6 . 
   In this manner, the memory for copying  5  and the fax memory  6  are shared, and the operations as mentioned above are controlled by the main CPU  401 . 
     FIG. 4  is a flow chart specifically showing the operation in the copy mode. First, when a copy request is made (S 1 ) and documents are set on a document tray (S 2 ), the reading of the documents is started (S 3 ), and the read image data is subjected to image processing and input of the image data into the memory for copying  5  is started (S 4 ). In parallel with the reading of the documents and storage of the image data, a copy process for outputting images onto sheets of paper is started (S 5 ). 
   In parallel with the reading of the documents and input of the image data, it is judged whether all the document have been read or not (S 6 ). In the case where all the documents have not been read, it is judged whether or not the memory for copying  5  has a free area (S 7 ). When a free area is available, the operation goes back to step S 6 . During a time that step S 7  is affirmed, the operation of reading the documents is continued until all the documents are read. When the reading of all the documents is finished at step S 5 , the document reading process is finished (S 8 ) When the memory for copying  5  becomes full at step S 7 , it is judged whether or not the fax memory  6  has a free area (S 9 ). When a free area is available, the image data is inputted and recorded in the fax memory  6  (S 10 ) and the operation goes back to step S 6 . During a time that step S 7  is denied, the reading of the documents is continued as long as the fax memory  6  has a free area. 
   At step S 9 , in the case where free area of the fax memory  6  is exhausted, the reading of the documents is once stopped because the memory is full (S 11 ). 
   On the other hand, in the copy process executed in parallel with input of the image data, it is judged whether the following copy data exist or not (S 12 ). In the case where the following copy data exist, the operation goes back to step S 5 , where the copy process is performed until all the copy data is processed. When all the copy data is processed, the copy process is finished (S 13 ). 
   When both the document reading process and the copy process executed in parallel are finished at steps S 8  and S 13 , all the operations are finished (S 14 ). In the case where either process has not been finished, the operation goes back to step S 3  or step S 5 . 
     FIG. 5  is a flow chart specifically showing the operation in the fax reception mode. When fax data is received (S 21 ), it is judged whether memory reception is selected or not (S 22 ) In the case where memory reception is selected, a receiving process is started (S 23 ). It is judged whether or not the fax memory  6  has a free area (S 24 ), and in the case where a free area is available, reception data is continuously accumulated in the fax memory  6  (S 25 ). Then, it is judged again whether or not the fax memory  6  has a free area (S 26 ), and in the case where a free area is available, reception data is continuously accumulated in the fax memory  6  (S 27 ). 
   Then, it is judged whether all the reception data has been accumulated or not (S 28 ), and the operation from step S 23  to S 28  is repeatedly performed until all the reception data is accumulated. 
   In the case where it is judged at step S 24  or S 26  that the facsimile memory  6  has no memory, it is judged whether or not memory for copying  5  has a free area (S 29 ). In the case where a free area is available, reception data is accumulated in the memory for copying  5 . In the case where it is judged at step S 29  that the memory for copying  5  has no free area, a busy signal is outputted to the transmission counterpart so as to stop transmission for a brief period of time (S 31 ). 
   On the other hand, in the case where it is judged at step S 22  that memory reception is not selected, it is judged whether direct reception is selected or not (S 32 ). In the case where direct reception is not selected, the operation goes back to step S 22 . In the case where direct reception is selected, parallel execution of a process of receiving data from the counterpart (S 33 ) and an image outputting process (S 34 ) is started. 
   Then, it is judged whether all the reception data has been outputted or not (S 35 ). In the case where all the reception data has not been outputted, the operation goes back to steps S 33  and S 34 , whereas in the case where all the reception data has been processed, the outputting process is finished (S 36 ) to finish all the operations. 
   The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and the range of equivalency of the claims are therefore intended to be embraced therein.