Image forming apparatus

The present invention is to provide an image forming apparatus including: automatic document feeding means for placing multiple originals in position and feeding the originals one by one; document reading means; printing means for printing on paper image data acquired by the reading means; document detecting means, provided in the automatic document feeding means, for detecting the originals; paper detecting means for detecting paper; operation means for capturing user's operations; and control means for receiving an interrupt operation instruction given by the user through the operation means, determining executable operation modes according to the transport states of the originals and paper detected by the document detecting means and the paper detecting means, and outputting the executable operation mode selected through the operation means.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image forming apparatus for reading image data from a source or original document, and printing the document image on recording paper (hereinafter simply called paper).

2. Description of the Related Art

Some kinds of image forming apparatuses, such as copying machines, incorporate a function, called an interrupt mode, for suspending processing currently in progress and performing another processing. Many of recent image forming apparatuses incorporate an automatic document feeder (ADF) in which multiple originals are placed and fed one by one for reading of image data. Suppose that one or more unread originals (interrupted job originals) remain in the automatic document feeder upon execution of another processing in an interrupt mode. In this case, the use of the automatic document feeder in the interrupt mode causes a mix-up between the precedent interrupted job originals and interrupt job originals. To avoid this, any conventional way of setting an interrupt mode is to prohibit users from selecting any mode with the potential to go into competition with the interrupted job.

For example, there are techniques for making the transition to the interrupt mode in such a way that allows the execution of the interrupt job only after a number of copies set for the interrupted job are completed (for example, refer to Japanese patent laid-open No. 10-026905). There is also another type of techniques for competition control and warning upon setting of an interrupt job. When setting of an interrupt mode leads to processing competition, this type of techniques provides a warning indication to urge the user to change the setting (for example, refer to Japanese patent laid-open No. 2001-010169).

Thus there is no conventional image forming apparatus that can determine, based on the results of checking the states of originals and paper in response to a request to execute an interrupt mode, which operation mode to select from those usable in the interrupt mode. In other words, since the conventional image forming apparatuses have previously eliminated operation modes with the potential to go into processing competition, operation modes executable in an interrupt mode are limited upon setting the interrupt mode. This makes the conventional image forming apparatuses less user-friendly.

SUMMARY OF THE INVENTION

The present invention has been made to solve the above conventional problem, and it is an object thereof to provide an image forming apparatus capable of increasing the number of operation modes executable in an interrupt mode.

To attain the object, in the first aspect of the present invention, there is provided an image forming apparatus comprising: automatic document feeding means for placing multiple originals in position and feeding the originals one by one; document reading means; printing means for printing on paper image data acquired by the reading means; document detecting means, provided in the automatic document feeding means, for detecting the originals; paper detecting means for detecting paper; operation means for capturing user's operations; and control means for receiving an interrupt operation instruction given by the user through the operation means, determining executable operation modes according to the transport states of the originals and paper detected by the document detecting means and the paper detecting means, and outputting the executable operation mode selected through the operation means.

In the second aspect of the present invention, the image forming apparatus as set forth in the first aspect of the present invention is such that, when an interrupt operation is instructed by the user while the originals are being fed by the automatic document feeding means, the control means completes the reading of the original being currently fed and stops the feeding of the following originals.

In the third aspect of the present invention, the image forming apparatus as set forth in the first aspect of the present invention is such that, when determining that there are no originals in the automatic document feeding means based on the detection result of the document detecting means, the control means enables the selection of an operation mode using the automatic document feeding means, while when determining there is one or more originals in the automatic document feeding means, the control means disables the selection of the operation mode using the automatic document feeding means.

In the fourth aspect of the present invention, the image forming apparatus as set forth in the first aspect of the present invention is such that, when an interrupt operation is instructed by the user while the originals are being fed by the automatic document feeding means, the control means not only completes the reading of the original being currently fed, but also feeds the following originals while counting the number of unread originals, and when determining that there are no originals in the automatic document feeding means based on the detection result of the document detection means, the control means enables the selection of an operation mode using the automatic document feeding means and outputs all pieces of originals corresponding to the number of unread originals to the operation means after completion of the interrupt operation.

In the fifth aspect of the present invention, the image forming apparatus as set forth in the first aspect of the present invention further comprises post processing means including at least stacking means for stacking sheets of paper on which printing have been done through the printing means, and binding means for binding the sheets of paper stacked on the stacking means, in which the paper detection means detects the presence or absence of paper in the post processing means, and when determining no paper in the post processing means based on the detection result of the paper detection means, the control means enables the selection of an operation mode using the post processing means, while when determining there is one or more sheets of paper in the post processing means, the control means disables the selection of the operation mode using the post processing means.

In the sixth aspect of the present invention, the image forming apparatus as set forth in the first aspect of the present invention further comprises reversing means for turning the paper upside down, in which the paper detection means detects the presence or absence of paper in the reversing means, and when determining no paper in the reversing means based on the detection result of the paper detection means, the control means enables the selection of an operation mode using the reversing means, while when determining there is one or more sheets of paper in the reversing means, the control means disables the selection of the operation mode using the reversing means.

In the image forming apparatus according to the present invention, the automatic document feeding means places originals in position and feeds them one by one to the reading means. The reading means acquires image data from each of the originals fed by the automatic document feeding means. The printing means prints on paper the image data acquired by the reading means, thus copying the document image onto paper.

During the above-mentioned copying operation, when an interrupt request is received from the user through the operation means, the control means controls the document detection means and the paper detection means to detect in what units the original and paper transported in the interrupted job (the copying operation in progress) are located. The control means outputs such an operation display screen to the operation means as to enable the selection of operation modes using units that are not being used in the interrupted job and disable the selection of operation modes using units that are used in the interrupted job. It enables the user to select an operation mode easily for sure in the interrupt operation.

It is apparent from the above description that the present invention is such that, when an interrupt request is made by a user's operation, executable operation modes are automatically determined according to the transport states of originals and paper in the interrupted job to enable the user to select an operation mode, so that the operation mode executable in the interrupt mode can be selected without any competition with the interrupted job, thus improving the convenience of users.

The above and many other objects, features and advantages of the present invention will become manifest to those skilled in the art upon making reference to the following detailed description and accompanying drawings in which preferred embodiments incorporating the principle of the present invention are shown by way of illustrative examples.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Some preferred embodiments of image forming apparatuses according to the present invention will now be described with reference to the accompanying drawings.FIG. 1is a schematic sectional view showing the internal structure of an image forming apparatus according to an embodiment of the present invention. An image forming apparatus1of the embodiment determines operation modes executable upon setting an interrupt mode from the loading and transport states of originals P1and paper P2, thus increasing the number of operation modes executable upon setting the interrupt mode.

The image forming apparatus1of the present invention includes an apparatus main body2, an automatic document feeder3, and a finisher4.

The structure of the apparatus main body2will first be described. As shown inFIG. 1, the apparatus main body2includes a scanner section5, a paper feeder section6, a printer section7, a fixing unit8, a delivery section9, a reversing unit10, and a transport section11. The scanner section5is an example of reading means, which is composed of a contact glass12on which an original is placed, a slit glass13, an image sensor14, a lamp15, a mirror group16that leads reflected light of the lamp15to the image sensor14.

The contact glass12is a rectangular plate glass of sufficient size to cover the size of any original P1placed on it. The slit glass13is a strip of glass extending in the main scanning direction. The lamp15and the mirror group16are driven by a driving mechanism, not shown, to move in the sub-scanning direction. These elements provide illumination across the entire surface of the original P1placed on the contact glass12so that the image sensor14can read the reflected light. Since the lamp15and the mirror group16are positioned underneath the slit glass13, the original P1fed by the automatic document feeder3in a manner described later can be illuminated so that the image sensor14will read the reflected light.

The paper feeder section6is composed of multiple paper feed cassettes17for holding paper P2of different sizes, and transport mechanisms18such as rollers for pulling out and transporting paper P2from each paper feed cassette17. Thus the paper feeder section6supplies a predetermined size of paper P2to the printer section7. The printer section7is an example of printing means, which is composed of a corona charger19, a photosensitive drum20, an exposure unit21, a developing unit22, a transfer charger23, a separation charger24, a cleaning unit25, etc.

The corona charger19charges the surface of the photosensitive drum20to a predetermined voltage prior to a latent-image formation process. The photosensitive drum20is made up of a cylindrical base member with its surface coated with a photosensitive layer, and driven to rotate by a driving mechanism, not shown. After making the photosensitive drum20uniformly charged by the corona charger19while rotating it, the exposure unit21performs exposures to form a latent image on the surface of the photosensitive drum20.

In the exposure unit21, a light beam projected from a laser, not shown, is reflected by a polygon mirror21aand incident on the surface of the photosensitive drum20. The polygon mirror21ais rotating at a constant rotational speed, and the rotation of the polygon mirror21acauses the laser beam to scan in the main scanning direction. On the other hand, the rotation of the photosensitive drum20causes the laser beam to scan in the sub-scanning direction. Thus the latent image is formed on the surface of the photosensitive drum20. The electrostatic latent image formed on the photosensitive drum20is made visible by means of the developing unit22.

The developing unit22includes a developing sleeve22aand a mechanism for agitating toner in the developing unit22and supplying the toner. The toner supplied by the developing sleeve22ato the photosensitive drum20is attracted to the latent image on the photosensitive drum20to form a toner image. The toner image on the photosensitive drum20is transferred from the photosensitive drum20to paper P2by the transfer charger23. Then the paper P2with the toner image transferred on it is separated from the photosensitive drum20by the separation charger24and sent to the fixing unit8. In other words, since the transfer charger23is arranged to face the photosensitive drum20, it discharges from the back side of the paper P2on the photosensitive drum20with the toner image electrostatically held on it, thus transferring the toner image onto the paper P2. The separation charger24neutralizes the charged surface of the paper P2stuck to the photosensitive drum20, and separates the paper P2from the photosensitive drum20.

The toner remaining on the photosensitive drum20without being transferred onto the paper P2is collected by the cleaning unit25. The cleaning unit25is equipped with a blade or the like that is arranged to contact the photosensitive drum20and scratch off and collect the toner adhering to the surface of the photosensitive drum20. The fixing unit8is a fuser26for fixing the toner image. As mentioned above, the paper P2on which the toner image has been transferred is sent to the fuser26in the printer section7. The fuser26fixes the toner to the paper P2through heat and pressure.

The delivery section9discharges the paper P2processed by the fixing unit8to the outside. The reversing unit (ADU: Automatic Duplex Unit)10is an example of reversing means, which is composed of a reversing transport path27and the like. The paper P2processed by the fixing unit8is sent to the reversing transport path27in which the paper P2is turned upside down before it is sent to the printer section7. The transport direction of the paper P2that has passed through the fixing unit8can be changed by a transport switching gate28so that the paper P2will be sent to either the delivery section9or the reversing unit10depending on the operation mode.

The transport section11is made up of a transport path and the like including the above-mentioned transport mechanisms18and the reversing transport path27; it transports the paper P2. A sensor group for detecting the transport state of the paper P2is provided in the transport section11. Among the sensors, a paper detection sensor29for detecting the presence or absence of the paper P2in the reversing transport path27is shown inFIG. 1. This paper detection sensor29is an example of paper detection means.

The structure of the automatic document feeder (ADF)3will next be described. The automatic document feeder3is an example of automatic document feeding means; it includes a document tray30, a paper output tray31, a reversing tray32, and a paper feed mechanism33. The paper feed mechanism33has a roller group such as a feed roller34arranged to face the slit glass13, and a paper feed roller for pulling out originals P1one by one from the document tray30. A sensor group for detecting the transport state of the originals P1is provided in the automatic document feeder3. Among these sensors, a document detection sensor36for detecting the presence or absence of any original P1on the document tray30and a document passing detection sensor37for detecting the completion of document feeding are shown inFIG. 1. The document detection sensor36and the document passing detection sensor37are examples of document detection means.

Next, the structure of the finisher4will be described. The finisher4is an example of post processing means, and is also called an after-treatment device. The finisher4shown in the embodiment is a stapler unit that includes a stacker38, a binder39, a main tray40, a sub-tray41, and a transport mechanism. The stacker38is an example of stacking means; it stacks sheets of paper P2discharged one by one from the apparatus main body2. The binder39is an example of binding means; it binds with a stapler multiple sheets of paper P2stacked on the stacker38. The sheets of paper P2stacked on the stacker38and bound in the form of a book are discharged into the main tray40. On the other hand, sheets of paper P2to be discharged one by one from the apparatus main body2are discharged into the sub-tray41one by one as they are delivered.

A sensor group for detecting the transport state of the paper P2is provided in the finisher4. Among these sensors, a paper detection sensor42for detecting the presence or absence of the paper P2on the stacker38is shown inFIG. 1. This paper detection sensor42is an example of paper detection means. Although not shown here, a mechanism for punching holes in the paper P2can also be provided in the finisher4.

The following describes the flows of originals P1and paper P2in the image forming apparatus1.

The flow of original P1in the automatic document feeder3will first be described. Multiple originals P1set on the document tray30of the automatic document feeder3are pulled out one by one by means of the paper feed roller35of the paper feed mechanism33, and transported over the slit glass13. Each original P1transported over the slit glass13is exposed to light from the lamp15so that reflected light from the original P1will be read in by the image sensor14. Since the original P1is thus transported, the overall image of the original P1can be read in.

When single-sided reading is set, the original P1passing through the slit glass13is ejected into the output tray31. When the double-sided reading is set, the original P1is sent to the reversing tray32, and to the feed roller34again. Thus the original P1is turned upside down, and fed over the slit glass13again to achieve the double-sided reading of the original P1. The operation mode using the automatic document feeder3in the manner mentioned above is called the ADF mode.

The flow of paper2in the apparatus main body2and the finisher4will next be described. Sheets of paper P2set in any paper feed cassette17are pulled out one by one by pull-out rollers as the transport mechanism18, and sent to the printer section7through transport rollers in the transport section11. After subjected to the printing process in the printer section7, the paper P2is sent to the fixing unit8. Then, when single-sided printing is set, the paper P2is sent from the delivery section9to the finisher4. When double-sided printing is set, the paper P2is sent from the fixing unit8to the reversing transport path27, and to the printer section7again after being turned upside down through the reversing transport path27. The operation mode for printing on both sides of the paper P2using the reversing unit10in the manner mentioned above is called the ADU mode.

When the paper P2sent to the finisher4is supposed to be outputted without after-treatment, it is ejected into the sub-tray4. When stapling is set, a predetermined number of sheets of paper P2are sent to the stacker38. Then, when the predetermined number of sheets of paper P2are stacked on the stacker38, they are stapled together in the binder39, and ejected into the main tray40. The operation mode for stapling using the finisher4in the manner mentioned above is called the staple mode.

Next, the control system of the image forming apparatus1will be described. The operation of the image forming apparatus is controlled by a control unit43provided in the apparatus main body2.

FIG. 2is a block diagram showing an example of the structure of the control system in the above-mentioned image forming apparatus as practiced in the embodiment of the present invention. The image forming apparatus1includes in the apparatus main body2the control unit43for controlling each component described in relation toFIG. 1, and an operation unit44through which the user performs operations. The transport section11in the apparatus main body2is provided with a sensor group45including the paper detection sensor29, and a drive unit46for driving the transport rollers and the like.

The automatic document feeder3is provided with a sensor group47including the document detection sensor36and the document passing detection sensor37, and a paper feed actuator48for actuating the paper feed mechanism33. The finisher4is provided with a sensor group49including the paper detection sensor42, and a drive unit50for a mechanism for stapling and transporting paper P2.

The control unit43is an example of control means; it controls the drive unit46of the apparatus main body2, the scanner section5, the printer section7, the paper feed actuator48of the automatic document feeder3, and the drive unit50of the finisher4, according to the contents of operations designated by the user through the operation unit44and the outputs of the sensor group45of the apparatus main body2, the sensor group47of the automatic document feeder3, and the sensor group49of the finisher4. The control unit43also causes the display of operation screens such as setting screens on the operation unit44in a manner described later.

The structure of the operation unit44will next be described.

FIG. 3shows an example of the arrangement of a key input part51on the operation unit, andFIG. 4is an illustration showing a display example of a display part52on the operation unit. The operation unit44is an example of operation means; it includes the key input part shown inFIG. 3and the display part52shown inFIG. 4arranged side by side on a front panel, not shown, of the apparatus main body2. As shown inFIG. 3, the key input part51has an interrupt button53for instructing an interrupt operation and a start button54for starting various kinds of operations. In addition to these buttons, the key input part51also has various other buttons, such as a button to switch among the functions of the image forming apparatus of multifunctional type, a numerical ten keypad to enter the number of copies and the like.

The display part52is, for example, a liquid crystal display with a touch panel on which a setting screen55ais displayed as shown inFIG. 4. The setting screen55aincludes an output form selection part56aand a duplex mode selection part56b,in each of which various buttons are displayed. The output form selection part56agives a choice of output forms of paper P2so that the user can select one of the output forms. The duplex mode selection part56agives a choice of options, such as an option to read an image from one side of original P1and print it on one side of paper P2, and an option to read images from both sides of original P1and print them on both sides of paper P2. In the output form selection part56a,buttons to switch between the presence and absence of the staple mode are displayed. In the duplex mode selection part56b,buttons to switch among reading and printing options to determine whether to select an operation mode for double-sided reading and double-sided printing so as to set the ADF mode and ADU mode are displayed. The setting screen55afurther includes a copy density selection part, a magnification ratio selection part, a paper size selection part, etc.

The image forming apparatus1enables the user to select an operation mode in the following way. The user touches a desired button on the setting screen55adisplayed on the display part52while viewing each of the selection parts, and then presses the start button54on the key input part51. For example, the user may select such a copying operation as to staple and output sheets of paper P2. InFIG. 4, selected buttons are displayed in reverse video, changing from black-on-white to white-on-black.

Next, the structure for processing image data in the image forming apparatus1will be described.

FIG. 5is a block diagram showing an example of the detailed structure of the control system in the image forming apparatus1. As shown, the scanner section5includes a CCD (Charge Coupled Device)61constituting the image sensor14shown inFIG. 1and a scanner controller62. The printer section7includes a laser diode (LD)63provided in the exposure unit21shown inFIG. 1, and a printer controller64. The operation unit44includes a liquid crystal display (LCD)65shown inFIG. 4and an operation unit controller66.

The control unit43described in relation toFIG. 2has the following image forming structure: a read processing unit67, a compression IC (Integrated Circuit)68, a DRAM (Dynamic Random Access Memory) control IC69, an image memory70, a decompression IC71, a write processing unit72, an image control CPU (Central Processing Unit)73, and a nonvolatile memory74.

The read processing unit67performs processing such as analog-to-digital conversion of image data outputted from the CCD61. The compression IC67compresses the image data in a predetermined format. The DRAM control IC69performs the writing and reading of the image data to and from the image memory70. The image memory70is a DRAM including a compression memory70afor storing compressed image data and a page memory70bfor storing image data in certain units. The decompression IC71decompresses the compressed image data. The write processing unit72performs processing such as digital-to-analog conversion of the image data, and outputs the processed image data to the laser diode63. The image control CPU73controls the scanner controller62and the printer controller64to acquire and print image data, while it controls the operation unit controller66to display a proper screen on the liquid crystal display65. The nonvolatile memory74stores programs such as one executed by the image control CPU.

To interface to external devices, the image forming apparatus1includes an image processing unit (print/scanner controller)75. The image processing unit75has a DRAM control IC76, an image memory77, a LAN (Local Area Network) I/F78, and a controller control CPU79. The DRAM control IC76performs the writing and reading of image data to and from the image memory77. The image memory77is a DRAM. The DRAM control IC76in the image processing unit75and the DRAM control IC69in the apparatus main body2are interconnected through a PCI (Peripheral Component Interconnect) bus80. The LAN I/F78connects the image forming apparatus1to a network, not shown. The controller control CPU79enables the image forming apparatus1to exchange image data with a personal computer(s), not shown, connected to the network.

The flow of image data will next be described usingFIG. 5. When image data is read from an original P1using the image forming apparatus1as a copying machine or scanner, the image data is read in by the CCD61, processed in the read processing unit67, compressed in the compression IC68, and stored in the compression memory70aof the image memory70under the control of the DRAM control IC69.

When electronic image data is read from a terminal such as a personal computer using the image forming apparatus1as a printer, the image data is first stored in the image memory77of the image processing unit75. Then the image data stored in the image memory77is read out by the DRAM control IC76of the image processing unit75, sent to the apparatus main body2though the PCI bus80, and stored in the page memory70bof the image memory70under the control of the DRAM control IC69. The image data stored in the page memory70bis read out by the DRAM control IC69, compressed by the compression IC68, and stored in the compression memory70aof the image memory70under the control of the DRAM control IC69.

When image data is printed on paper P2using the image forming apparatus1as a copying machine or printer, the image data stored in the compression memory70aof the image memory70is read by the DRAM control IC69, decompressed by the decompression IC71, sent to the laser diode63by means of the write processing unit72, and printed on the paper P2through the mechanism described in relation toFIG. 1.

When image data is externally outputted using the image forming apparatus1as a scanner, the image data stored in the compression memory70aof the image memory70is read out by the DRAM control IC69, decompressed by the decompression IC71, and stored in the page memory70bof the image memory70under the control of the DRAM control IC69. Then the image data stored in the page memory70bis read out by the DRAM control IC69, sent to the image processing unit75through the PCI bus80, and stored in the image memory77under the control of the DRAM control IC76. The image data stored in the image memory77is transmitted by the LAN I/F78to a terminal through a network, not shown.

Next, the operation of the image forming apparatus shown in the above embodiment of the present invention will be described.

The image forming apparatus1of the present invention is enabled to select either of two operation modes, namely either an “interrupt mode to interrupt operation after completion of a required number of copies” as shown in the following first to third operation examples or an “interrupt mode to interrupt operation halfway through making the required number of copies (also called an instant stop mode)” as shown in the fourth operation example. These operation modes are preset as initial settings, and when the execution of the interrupt mode is requested, an operation is performed according to the initial setting.

FIGS. 6 to 8are flowcharts showing the first operation example of the image forming apparatus1of the present invention. The following description of the operation also refers toFIGS. 1 to 4as appropriate.

First, the control unit43causes the display of the setting screen55a,shown inFIG. 4, on the display part52of the operation unit44(step SA1). The user sees this setting screen55aand selects a desired operation mode (step SA2). In the first operation example, suppose that the user has selected such an operation mode as to read image data from one side of each of originals P1, print the image data on one side of each sheet of paper P2, and output the sheets of paper P2without being stapled.

When the user sets originals P1on the document tray30of the automatic document feeder3, the document detection sensor36detects “the presence of originals (step SA3). When detecting “the press of the start button54” on the operation unit44shown inFIG. 3(step SA4), the control unit43starts copying operation according to the operation mode selected by the user (step SA5). Then, when the interrupt button53shown inFIG. 3is pressed, the precedent copying operation becomes an interrupted job. Therefore, the control unit43keeps track of whether the interrupt button53is pressed or not (step SA6). When not detecting “the press of the interrupt button53” at step SA6, the control unit43controls the paper feed actuator48shown inFIG. 2to feed the originals P1one by one, controls the scanner section5to read image data from each original P1, and controls the printer section7to print (or copy) the image data on each sheet of paper P2(step SA7).

The control unit43detects the presence or absence of originals from the outputs of the document detection sensor36and the document passing detection sensor37to determine whether the reading of all the originals P1set on the document tray30has been completed (step SA8). In other words, when the document detection sensor36detects “no originals” and the document passing detection sensor37detects that “the rear end of the last original P1has passed,” the control unit43determines that the reading of all the originals P1has been completed.

On the other hand, when determining at step SA8that the reading of all the originals P1has not been completed yet, the control unit43returns to step SA6to keep track of, the presence or absence of the press of the interrupt button53while continuing the paper feeding and copying operations.

Then, when determining at step SA6that “the interrupt button53has been pressed,” the control unit43determines, from the output of the document passing detection sensor37, the presence or absence of any original P1that is in the process of being read. When the control unit43determines that “there is an original P1in the process of being read,” the transportation and reading of the original P1in process are continued. Then, when the document passing detection sensor37detects that the rear end of the original P1has passed, further feeding is inhibited.

The control unit43can also determine, from the output of the sensor group45and the like, the presence or absence of paper P2in the process of printing on it. Then, after a sheet of paper P2is pulled out from one of the paper feed cassettes17, when the control unit43determines that “there is paper P2in the process of printing on it” in the transport path, the transportation of and printing on the paper P2are continued. Finally, the paper P2on which printing has been done is ejected into the sub-tray41shown inFIG. 1and further printing is inhibited (step SA9).

Next, the control unit43causes the display of a predetermined interrupt copy setting screen on the display part52of the operation unit44according to the outputs of the sensors to urge the user to do various settings such as to set an output form in the interrupt mode (step SA10).

FIG. 9is an illustration showing an example of the interrupt copying setting screen. When “the press of the interrupt button53” is detected at step SA6, since it means that the reading operation was halted with one or more unread originals P1remaining on the document tray30of the automatic document feeder3, the document detection sensor36detects “the presence of one or more originals.” Therefore, the control unit43causes an interrupt copy setting screen55bwith “the selection of the ADF (RADF) mode disabled” as an operation mode using the automatic document feeder3, and displays it on the display part52of the operation unit44. In other words, the buttons to select the double-sided reading operations in the duplex mode selection part56bon the interrupt copy setting screen55bare shown with half-tone dot meshing to indicate that the selection of these operations is disabled.

The user sees the interrupt copy setting screen55b(seeFIG. 9) displayed on the display part52and selects an operation mode in the interrupt mode (step SA11). Then, the user places an original P1on the contact glass12and presses the start button54(step SA12). When detecting “the press of the start button54” at step SA12, the control unit43starts the interrupt copying operation according to the operation mode selected by the user at step SA11(step SA13). In this copying operation, even if detecting that “there is one or more originals” on the document tray30from the output of the document detection sensor36of the automatic document feeder3, the control unit43inhibits the automatic document feeder3from performing the document feeding operation. Instead, the control unit43controls the scanner section5to read an image of the original P1on the contact glass12and the printer section7to perform printing. After completion of the interrupt copying operation (step SA14), the control unit43returns to step SA4. Then, when detecting “the press of the start button54,” the control unit43resumes the interrupted job.

After that, when determining the completion of reading image data of all the originals P1at step SA8, the control unit43continuously monitors the presence or absence of the press of the interrupt button53during printing operation (step SA15). Then, when detecting “the press of the interrupt button53,” the control unit43determines, from the output of the sensor group45and the like, the presence or absence of paper P2in the process of printing on it. When determining that “there is a sheet of paper P2in the process of printing on it” after pulled out from one of the paper feed cassettes17, the control unit43continues the transportation of and printing on the paper P2in process. Then, after the paper P2on which printing has been done is ejected into the sub-tray41, the control unit43inhibits further printing (step SA16).

After that, the control unit43causes the display of a predetermined interrupt copy setting screen on the display part52of the operation unit44according to the outputs of the sensors (step SA17).

FIG. 10is an illustration showing another example of the interrupt copy setting screen. When “the press of the interrupt button53” is detected ate step SA15, since it means that no originals P1remain on the document tray30of the automatic document feeder3, the document detection sensor36detects “the absence of originals.” Therefore, the control unit43causes an interrupt copy setting screen55cwith the selection of the ADF mode enabled, and displays it on the display part52. In other words, the buttons to select the double-sided reading of originals P1in the duplex mode selection part56bon the interrupt copy setting screen55care activated and become selectable.

The user sees the interrupt copy setting screen55c(seeFIG. 10) displayed on the display part52and selects an operation mode in the interrupt mode (step SA18). Then, the user presses the start button54(step SA19). When detecting “the press of the start button54” at step SA19, the control unit43starts the interrupt copying operation according to the operation mode selected by the user at step SA18(step SA20). In this copying operation, if an original P1is placed on the contact glass12, the control unit43controls the scanner section5to read an image of the original P1on the contact glass12and the printer section7to perform printing. Further, when detecting “the presence of one or more originals” on the document tray30from the output of the document detection sensor36of the automatic document feeder3, the control unit43controls the automatic document feeder3to perform the document feeding operation, while controlling the scanner section5to read images one by one from the originals and the printer section7to perform printing. After completion of the interrupt copying operation (step SA21), the control unit43resumes monitoring the presence or absence of the press of the start button54(step SA22). Then, when detecting “the press of the start button54” at step SA22, the control unit43returns to step SA15.

When not detecting “the press of the interrupt button53” at step SA15, the control unit43continues the printing operation of the interrupted job (step SA23). Then, after the completion of printing of a set number of copies (step SA24), the copying operation for the interrupted job is completed.

FIGS. 11 to 13are flowcharts showing the second operation example of the image forming apparatus1of the present invention. The following description of the operation also refers toFIGS. 1 to 4as appropriate.

First, the control unit43causes the display of the setting screen55a(seeFIG. 4) on the display part52of the operation unit44(step SB1). The user sees this setting screen55aand selects a desired operation mode (step SB2). In the second operation example, suppose that the user has selected such an operation mode as to read image data from one side of each of originals P1, print the image data on one side of each sheet of paper P2, and staple and output the sheets of paper P2.

When the user sets originals P1on the document tray30of the automatic document feeder3, the document detection sensor36detects “the presence of originals (step SB3). When detecting “the press of the start button54” on the operation unit44shown inFIG. 3(step SB4) the control unit43starts copying operation according to the operation mode selected by the user (step SB5). The control unit43also monitors the presence or absence of the press of the interrupt button53on the operation unit44(step SB6). When not detecting “the press of the interrupt button53” at step SB6, the control unit43controls the paper feed actuator48to feed the originals P1one by one, controls the scanner section5to read image data from each original P1, and controls the printer section7to print (or copy) the image data on each sheet of paper P2. Further, the control unit43controls the drive unit50to stack a predetermined number of sheets of paper P2on the stacker38, staple the sheets together by means of the binder39, and eject them into the main tray40(step SB7).

The control unit43detects the presence or absence of originals from the outputs of the document detection sensor36and the document passing detection sensor37to determine whether the reading of all the originals P1set on the document tray30has been completed (step SB8). In other words, when the document detection sensor36detects “no originals” and the document passing detection sensor37detects that “the rear end of the last original P1has passed,” the control unit43determines that the reading of all the originals P1has been completed.

On the other hand, when determining at step SB8that the reading of all the originals P1has not been completed yet, the control unit43returns to step SB6to keep track of the presence or absence of the press of the interrupt button53while continuing the paper feeding and copying operations.

Then, when determining at step SB6that “the interrupt button53has been pressed,” the control unit43determines, from the output of the document passing detection sensor37, the presence or absence of any original P1in the process of being read. When the control unit43determines that “there is an original P1in the process of being read,” the transportation and reading of the original P1in process are continued. Then, when the document passing detection sensor37detects that the rear end of the original P1has passed, further feeding is inhibited.

The control unit43can also determine, from the output of the sensor group45and the like, the presence or absence of paper P2in the process of printing on it. Then, after a sheet of paper P2is pulled out from one of the paper feed cassettes17, when the control unit43determines that “there is paper P2in the process of printing on it” in the transport path, the transportation of and printing on the paper P2are continued. Finally, the paper P2on which printing has been done is ejected into the stacker38and further printing is inhibited (step SB9).

Next, the control unit43determines the presence or absence of paper P2on the stacker38from the detection result of the paper detection sensor42(step SB10). When determining “no paper P2on the stacker38” at step SB10, the control unit43causes the display of the interrupt copy setting screen55bshown inFIG. 9on the display part32(step SB11).

In other words, since the control unit43has determined at step SB10“no paper on the stacker38,” the paper P2can be stacked on the stacker38without being mixed up with paper P2for the interrupted job. Therefore, the control unit43causes the interrupt copy setting screen55bwith the selection of the staple mode enabled, as an operation mode using the stacker38, and displays it on the display part52. When “the press of the interrupt button53” is detected at step SB6, since it means that the reading operation was halted with one or more unread originals P1remaining on the document tray30of the automatic document feeder3, the document detection sensor36detects “the presence of one or more originals.” Thus the selection of the ADF mode using the automatic document feeder3is disabled. In other words, the buttons to select the double-sided reading of originals P1in the duplex mode selection part56bon the interrupt copy setting screen55bare shown with half-tone dot meshing to indicate that the selection of these operations is disabled.

When determining “the presence of paper P2on the stacker38” at step SB10, the control unit43causes an interrupt copy setting screen with the selection of the staple mode disabled, and displays it on the display part52(step SB12).

FIG. 14is an illustration showing a display example of the interrupt copy setting screen. Since the control unit43has determined “the presence of paper on the stacker38” at step SB10, if paper P2for the interrupt job is sent to the stacker38, it will be mixed up with those of paper P2for the interrupted job. Therefore, the control unit43causes an interrupt copy setting screen55dwith the selection of the staple mode using the stacker38disabled, and displays it on the display part52. In other words, the button to select the binding operation in the output form selection part56aon the interrupt copy setting screen55dis shown with half-tone dot meshing to indicate that the selection of this operation is disabled. The reason why the selection of the ADF mode is disabled in the duplex mode selection part56bon the interrupt copy setting screen55ddisplayed in response to the processing step SB12is that, as mentioned above, the reading operation was halted with one or more unread originals P1remaining on the document tray30of the automatic document feeder3.

The user sees the interrupt copy setting screen55ddisplayed on the display part52according to the detection results of the paper detection sensor42and the like, such as the presence or absence of paper P2, and selects an operation mode in the interrupt mode (step SB13). Then, the user places an original P1on the contact glass12and presses the start button54(step SB14). When detecting “the press of the start button54” at step SB14, the control unit43starts the interrupt copying operation according to the operation mode selected by the user at step SB13(step SB15). In this copying operation, even if detecting that “there is one or more originals” on the document tray30from the output of the document detection sensor36of the automatic document feeder3, the control unit43inhibits the automatic document feeder3from performing the document feeding operation. Instead, the control unit43controls the scanner section5to read an image of the original P1on the contact glass12and the printer section7to perform printing. After completion of the interrupt copying operation (step SB16), the control unit43returns to step SB4, and when detecting “the press of the start button54” at step SB4, it resumes the interrupted job.

When determining the completion of reading image data of all the originals P1at step SB8, the control unit43continuously monitors the presence or absence of the press of the interrupt button53during printing operation (step SB17). Then, when detecting “the press of the interrupt button53” at step SB17, the control unit43determines, from the output of the sensor group45and the like, the presence or absence of paper P2in the process of printing on it. When it is determined that “there is a sheet of paper P2in the process of printing on it” after pulled out from one of the paper feed cassettes17, the transportation of and printing on the paper P2in process are continued. Then, after the paper P2on which printing has been done is ejected into the stacker38, further printing is inhibited (step SB18).

Next, the control unit43determines the presence or absence of paper P2on the stacker38from the detection result of the paper detection sensor42(step SB19). When determining that “there is no paper P2on the stacker38” at step SB19, the control unit43causes the interrupt copy setting screen55cshown inFIG. 10, and displays it on the display part52(step SB20).

In other words, since the control unit43has determined at step SB19“no paper on the stacker38,” the paper P2can be stacked on the stacker38without being mixed up with paper P2for the interrupted job. Therefore, the control unit43causes the interrupt copy setting screen55cwith the selection of the staple mode using the stacker38of the finisher4enabled, and displays it on the display part52. When “the press of the interrupt button53” is detected at step SB17, since it means that no originals P1remain on the document tray30of the automatic document feeder3, the document detection sensor36detects “the absence of originals.” Thus the selection of the ADF mode is enabled. In other words, all the buttons in the output form selection part56aand the duplex mode selection part56bon the interrupt copy setting screen55care activated and become selectable.

When determining “the presence of paper P2on the stacker38” at step SB19, the control unit43causes an interrupt copy setting screen with the selection of the staple mode disabled, and displays it on the display part52(step SB21).FIG. 15is an illustration showing another example of the interrupt copy setting screen in the second operation example. Since the control unit43has determined “the presence of paper on the stacker38” at step SB19, if paper P2for the interrupt job is sent to the stacker38, it will be mixed up with those of paper P2for the interrupted job. Therefore, the control unit43causes an interrupt copy setting screen55ewith the selection of the staple mode using the stacker38of the finisher4disabled, and displays it on the display part52. In other words, the button to select the binding operation in the output form selection part56aon the interrupt copy setting screen55eis shown with half-tone dot meshing to indicate that the selection of this operation is disabled.

The user sees the interrupt copy setting screen55edisplayed on the display part52according to the detection results of the paper detection sensor42and the like, such as the presence or absence of paper P2, and selects an operation mode in the interrupt mode (step SB22). Then, the user presses the start button54(step SB23). When detecting “the press of the start button54” at step SB23, the control unit43starts the interrupt copying operation according to the operation mode selected by the user at step SB22(step SB24). In this copying operation, if an original P1is placed on the contact glass12, the control unit43controls the scanner section5to read an image of the original P1on the contact glass12and the printer section7to perform printing. Further, when the ADF mode is selected and “the presence of one or more originals” on the document tray30is detected from the output of the document detection sensor36of the automatic document feeder3, the control unit43controls the automatic document feeder3to perform the document feeding operation, while controlling the scanner section5to read images one by one from the originals P1and the printer section7to perform printing. Further, when the staple mode is selected, the control unit43stacks a predetermined number of sheets of paper P2on the stacker38, staples the sheets together by means of the binder39, and ejects the stack of paper into the main tray40. After completion of the interrupt copying operation (step SB25), the control unit43continuously monitors the presence or absence of the press of the start button54(step SB26). When detecting “the press of the start button54” at step SB26, the control unit43returns to step SB17.

When not detecting “the press of the interrupt button53” at step SB17, the control unit43continues the printing operation of the interrupted job (step SB27). Then, after the completion of printing of a set number of copies (step SB28), the copying operation for the interrupted job is completed.

FIGS. 16 to 18are flowcharts showing the third operation example of the image forming apparatus1of the present invention. The following description of the operation also refers toFIGS. 1 to 4as appropriate. First, the control unit43causes the display of the setting screen55ashown inFIG. 4on the display part52of the operation unit44(step SC1). The user sees this setting screen55aand selects a desired operation mode (step SC2). In the third operation example, suppose that the user has selected the ADU mode as such an operation mode as to read image data from one side of each of originals P1and print the image data on both side of each sheet of paper P2.

When the user sets originals P1on the document tray30of the automatic document feeder3, the document detection sensor36detects “the presence of originals (step SC3). Then, when detecting “the press of the start button54” (step SC4), the control unit43starts copying operation according to the operation mode selected by the user (step SC5). Further, the control unit43keeps track of whether the interrupt button53on the operation unit44is pressed or not (step SC6). When not detecting “the press of the interrupt button53” at step SC6, the control unit43controls the paper feed actuator48to feed the originals P1one by one, controls the scanner section5to read image data from each original P1, and controls the printer section7to print (or copy) the image data on each sheet of paper P2. In the ADU mode, paper P2on one side of which printing has been done is sent to the reversing transport path to turn the paper P2upside down. Then the paper P2is sent to the printer section7again, thus performing double-sided printing (step SC7). The control unit43detects the presence or absence of originals from the outputs of the document detection sensor36and the document passing detection sensor37to determine whether the reading of all the originals P1set on the document tray30has been completed (step SC8). In other words, when the document detection sensor36detects “no originals” and the document passing detection sensor37detects that “the rear end of the last original P1has passed,” the control unit43determines that the reading of all the originals P1has been completed. On the other hand, when determining at step SC8that the reading of all the originals P1has not been completed yet, the control unit43returns to step SC6to keep track of the presence or absence of the press of the interrupt button53while continuing the paper feeding and copying operations.

Then, when determining at step SC6that “the interrupt button53has been pressed,” the control unit43determines, from the output of the document passing detection sensor37, the presence or absence of any original P1that is in the process of being read. When the control unit43determines that “there is an original P1in the process of being read,” the transportation and reading of the original P1in process are continued. Then, when the document passing detection sensor37detects that “the rear end of the original P1has passed,” the control unit43inhibits further feeding.

The control unit43also determines, from the output of the sensor group45and the like, the presence or absence of paper P2in the process of printing on it. Then, after a sheet of paper P2is pulled out from one of the paper feed cassettes17, when the control unit43determines that “there is paper P2in the process of printing on it” in the transport path, the transportation of and printing on the paper P2are continued. Finally, the paper P2on which printing has been done is ejected into the sub-tray41and further printing is inhibited (step SC9).

Next, the control unit43determines the presence or absence of paper P2in the reversing unit10from the output of the paper detection sensor29of the reversing unit10(step SC10). When determining “no paper P2in the reversing unit10” at step SC10, the control unit43causes the display of the interrupt copy setting screen55bshown inFIG. 9on the display part52(step SC11).

In other words, since the control unit43has determined at step SC10“no paper in the reversing unit10,” the paper P2can be stacked in the reversing unit10without being mixed up with paper P2for the interrupted job. Therefore, the control unit43causes the interrupt copy setting screen55bwith “the selection of the ADU mode enabled” as an operation mode using the reversing unit10, and displays it on the display part52. When “the press of the interrupt button53” is detected at step SC6, since it means that the reading operation was halted with one or more unread originals P1remaining on the document tray30of the automatic document feeder3, the document detection sensor36detects “the presence of one or more originals.” Thus the selection of the ADF mode using the automatic document feeder3is disabled. In other words, the buttons to select the double-sided reading of originals p1in the duplex mode selection part56bon the interrupt copy setting screen55bare shown with half-tone dot meshing to indicate that the selection of these operations is disabled.

On the other hand, when determining at step SC10that “there is paper P2in the reversing unit10,” the control unit43causes an interrupt copy setting screen with the selection of the ADU mode disabled, and displays it on the display part52(step SC12).FIG. 19is an illustration showing an example of the interrupt copying setting screen. Since the control unit43has determined “the presence of paper in the reversing unit10” at step SC10, if paper P2for the interrupt job is sent to the reversing unit, it will be mixed up with those of paper P2for the interrupted job. Therefore, the control unit43causes an interrupt copy setting screen55fwith the selection of the ADU mode disabled, as an operation mode using the reversing unit10, and displays it on the display part52. In other words, the buttons to select the double-sided printing on paper P2in the duplex mode selection part56bon the interrupt copy setting screen55fare shown with half-tone dot meshing to indicate that the selection of these operations is disabled. As shown on the interrupt copy setting screen55fofFIG. 19, the ADF mode is also disabled in response to the processing step SC12the reason why the selection of the ADF mode is also disabled in response to the processing step SC12is that, as mentioned above, the reading operation was halted with one or more unread originals P1remaining on the document tray30of the automatic document feeder3.

The user sees the interrupt copy setting screen55fdisplayed on the display part52according to the detection results of the paper detection sensor42and the like, such as the presence or absence of paper P2, and selects an operation mode in the interrupt mode (step SC13). Then, the user places an original P1on the contact glass12and presses the start button54(step SC14). When detecting “the press of the start button54” at step SC14, the control unit43starts the interrupt copying operation according to the operation mode selected by the user at step SC13(step SC15). In this copying operation, even if detecting that “there is one or more originals” on the document tray30from the output of the document detection sensor36of the automatic document feeder3, the control unit43inhibits the automatic document feeder3from performing the document feeding operation. Instead, the control unit43controls the scanner section5to read an image of the original P1on the contact glass12and the printer section7to perform printing. After completion of the interrupt copying operation (step SC16), the control unit43returns to step SC4, and when detecting “the press of the start button54” at step SC4, it resumes the interrupted job.

After that, when determining “the completion of reading image data of all the originals P1” at step SC8, the control unit43continuously monitors the presence or absence of the press of the interrupt button53during printing operation (step SC17). Then, when detecting “the press of the interrupt button53” at step SC17, the control unit43determines, from the output of the sensor group45and the like, the presence or absence of paper P2in the process of printing on it.

Then, after a sheet of paper P2is pulled out from one of the paper feed cassettes17, when the control unit43determines that “there is paper P2in the process of printing on it” in the transport path, the transportation of and printing on the paper P2are continued. Finally, the paper P2on which printing has been done is ejected into the sub-tray41and further printing is inhibited (step SC18).

Next, the control unit43determines the presence or absence of paper P2in the reversing unit10from the detection result of the paper detection sensor29of the reversing unit (step SC19). When determining “no paper P2in the reversing unit10” at step SC19, the control unit43causes the display of the interrupt copy setting screen55cshown inFIG. 10on the display part52(step SC20).

In other words, since the control unit43has determined at step SC19“no paper in the reversing unit10,” the paper P2can be stacked in the reversing unit10without being mixed up with paper P2for the interrupted job. Therefore, the control unit43causes the interrupt copy setting screen55cwith “the selection of the ADU mode enabled” as an operation mode using the reversing unit10, and displays it on the display part52. When the press of the interrupt button53is detected at step SC17, since no originals P1remain on the document tray30of the automatic document feeder3, the document detection sensor36detects “the absence of originals.” Thus the selection of the ADF mode is also enabled. In other words, all the buttons in the output form selection part56aand the duplex mode selection part56bon the interrupt copy setting screen55care activated and become selectable.

On the other hand, when determining at step SC19that “there is paper P2in the reversing unit10,” the control unit43causes an interrupt copy setting screen with the selection of the ADU mode disabled, and displays it on the display part52(step SC21).

FIG. 20is an illustration showing still another example of the interrupt copying setting screen. Since the control unit43has determined “the presence of paper in the reversing unit10” at step SC19, if paper P2for the interrupt job is sent to the reversing unit10, it will be mixed up with those of paper P2for the interrupted job. Therefore, the control unit43causes an interrupt copy setting screen55gwith the selection of the ADU mode disabled, as an operation mode using the reversing unit10, and displays it on the display part52. In other words, the buttons to select the double-sided printing of paper P2in the duplex mode selection part56bon the interrupt copy setting screen55gare shown with half-tone dot meshing to indicate that the selection of these operations is disabled.

The user sees the interrupt copy setting screen55gdisplayed on the display part52according to the detection results of the paper detection sensor42and the like, such as the presence or absence of paper P2, and selects an operation mode in the interrupt mode (step SC22). Then, the user presses the start button54(step SC23). When detecting “the press of the start button54” at step SC23, the control unit43starts the interrupt copying operation according to the operation mode selected by the user at step SC22(step SC24). In this copying operation, if an original P1is placed on the contact glass12, the control unit43controls the scanner section5to read an image of the original P1on the contact glass12and the printer section7to perform printing. Further, when the ADF mode is selected and the presence of one or more originals on the document tray30is detected from the output of the document detection sensor36of the automatic document feeder3, the control unit43controls the automatic document feeder3to perform the document feeding operation, while controlling the scanner section5to read images one by one from the originals P1and the printer section7to perform printing. Further, when the ADU mode is selected, paper P2on one side of which printing has been done is sent to the reversing transport path27to turn the paper P2upside down. Then the paper P2is sent to the printer section7again, thus performing double-sided printing. After completion of the interrupt copying operation (step SC25), the control unit43continuously monitors the presence or absence of the press of the start button54(step SC26). When detecting “the press of the start button54” at step SC26, the control unit43returns to step SC17.

When not detecting “the press of the interrupt button53” at step SC17, the control unit43continues the printing operation of the interrupted job (step SC27). Then, after completion of printing of a set number of copies (step SC28), the copying operation of the interrupted job is completed.

FIGS. 21 to 23are flowcharts showing the fourth operation example of the image forming apparatus1of the present invention. The fourth operation example shows a case where the interrupt mode to interrupt operation halfway through making the required number of copies is selected as the initial setting. First, the control unit43causes the display of the setting screen55a,shown inFIG. 4, on the display part52of the operation unit44(step SD1). The user sees this setting screen55aand selects a desired operation mode (step SD2). In the fourth operation example, suppose that the user has selected such an operation mode as to read image data from one side of each of originals P1, print the image data on one side of each sheet of paper P2, and output the sheets of paper P2without being stapled. When the user sets originals P1on the document tray30of the automatic document feeder3, the document detection sensor36detects “the presence of originals (step SD3). When detecting “the press of the start button54” on the operation unit44(step SD4), the control unit43starts copying operation according to the operation mode selected by the user (step SD5). The control unit43also monitors the presence or absence of the press of the interrupt button53on the operation unit44(step SD6). When not detecting “the press of the interrupt button53” at step SD6, the control unit43controls the paper feed actuator48to feed the originals P1one by one, controls the scanner section5to read image data from each original P1, and controls the printer section7to print (or copy) the image data on each sheet of paper P2(step SD7).

The control unit43detects the presence or absence of originals from the outputs of the document detection sensor36and the document passing detection sensor37to determine whether the reading of all the originals P1set on the document tray30has been completed (step SD8). In other words, when the document detection sensor36detects no originals and the document passing detection sensor37detects that the rear end of the last original P1has passed, the control unit43determines that the reading of all the originals P1has been completed. On the other hand, when determining at step SD8that the reading of all the originals P1has not been completed yet, the control unit43returns to step SD6to keep track of the presence or absence of the press of the interrupt button53while continuing the paper feeding and copying operations.

Then, when determining at step SD6that the interrupt button53has been pressed, the control unit43determines, from the output of the document passing detection sensor37, the presence or absence of any original P1that is in the process of being read. When the control unit43determines that “there is an original P1in the process of being read,” the transportation and reading of the original P1in process are continued. Further, the control unit43controls the paper feed actuator48to feed to the output tray31the originals P1subsequent to the one being currently read and remaining on the document tray30, and counts and stores the number of paper feeds from the output of the document passing detection sensor37. This paper feeding does not involve reading of image data. Then, when the document passing detection sensor37detects that the rear end of the last original P1has passed, the control unit43inhibits further feeding.

The control unit43also determines, from the output of the sensor group45and the like, the presence or absence of paper P2in the process of printing on it. Then, after a sheet of paper P2is pulled out from one of the, paper feed cassettes17, when the control unit43determines that there is paper P2in the process of printing on it, the transportation of and printing on the paper P2are continued. Finally, the paper P2on which printing has been done is ejected into the sub-tray41and further printing is inhibited (step SD9).

Next, the control unit43causes the display of the predetermined interrupt copy setting screen55cshown inFIG. 10on the display part52(step SD10). In other words, when the press of the interrupt button53is detected at step SD6, since all the originals P1are ejected from the document tray30of the automatic document feeder3into the output tray31at step SD9, no originals P1remain on the document tray30and the document detection sensor36detects no originals. Thus the selection of the ADF mode is enabled. In other words, all the buttons in the duplex mode selection part56bon the interrupt copy setting screen55care activated and become selectable.

The user sees the interrupt copy setting screen55cshown inFIG. 10on the display part52and selects an operation mode in the interrupt mode (step SD11). Then, the user presses the start button54(step SD12). When detecting “the press of the start button54” at step SD12, the control unit43starts the interrupt copying operation according to the operation mode selected by the user at step SD11(step SD13). In this copying operation, if an original P1is placed on the contact glass12, the control unit43controls the scanner section5to read an image of the original P1on the contact glass12and the printer section7to perform printing. Further, when detecting “the presence of one or more originals” on the document tray30from the output of the document detection sensor36of the automatic document feeder3, the control unit43controls the automatic document feeder3to perform the document feeding operation, while controlling the scanner section5to read images one by one from the originals and the printer section7to perform printing. After completion of the interrupt copying operation (step SD14), the control unit43causes the display of data on the number of unread originals stored at step SD9, and displays it on the display part52as data on the number of originals to be sent back to the automatic document feeder3(step SD15). After displaying at step SD15the data on the number of originals to be sent back, the control unit43returns to step SD3to keep track of the output of the document detection sensor36so as to determine whether the originals P1are set again on the document tray30. Then, when detecting the presence of the originals at step SD3and the press of the start button54at step SD4, the control unit43resumes the interrupted job.

After that, when determining the completion of reading image data of all the originals P1at step SD8, the control unit43continuously monitors the presence or absence of the press of the interrupt button53during printing operation (step SD16). Then, when detecting the press of the interrupt button53at step SD16, the control unit43determines, from the output of the sensor group45and the like, the presence or absence of paper P2in the process of printing on it. When determining that there is a sheet of paper P2in the process of printing on it after pulled out from one of the paper feed cassettes17, the control unit43continues the transportation of and printing on the paper P2in process. Then, after the paper P2on which printing has been done is ejected into the sub-tray41, the control unit43inhibits further printing (step SD17).

Next, the control unit43causes the display of the interrupt copy setting screen55cshown inFIG. 10on the display part52(step SD18). The user sees the interrupt copy setting screen55cshown inFIG. 10and displayed on the display part52, and selects an operation mode in the interrupt mode (step SD19). Then, the user presses the start button54(step SD20). When detecting “the press of the start button54” at step SD20, the control unit43starts the interrupt copying operation according to the operation mode selected by the user at step SD19(step SD21). After completion of the interrupt copying operation (step SD22), the control unit43continuously monitors the presence or absence of the press of the start button54(step SD23). Then, when detecting “the press of the start button54” at step Sd23, the control unit43returns to step SA16.

When not detecting “the press of the interrupt button53” at step SD16, the control unit43continues the printing operation of the interrupted job (step SD24). Then, after the completion of printing of a set number of copies (step SD25), the copying operation for the interrupted job is completed.

Although not shown here, if the staple mode or ADU mode is selected for the interrupted job in the fourth operation example, the control unit43will determine selectable operation modes in response to the press of the interrupt button53according to the detection results of the paper detection sensors29and45, such as the presence or absence of paper.

In the fourth operation example, if the interrupted job is in the ADF mode, since the originals P1for the interrupted job are made to retreat from the document tray30, the ADF mode is selectable in the interrupt mode regardless of the timing of interruption. Thus the number of selectable operation modes can be increased.

INDUSTRIAL APPLICABILITY

The present invention can be applied to image forming apparatuses called all-in-one or multifunctional machines that combine functions such as a copier, printer, facsimile, etc.