Image-forming apparatus with interrupt printing function

Provided is an image-forming apparatus that prevents a drop in processing speed even when a preceding job is interrupted by a simple job (interrupt job). The image-forming apparatus includes a printer unit that prints on paper, a first transporting path that passes by the printer unit, a second transporting path that path branches off from the first transporting path and moves paper that has been turned over from front to back further upstream than the printer unit, a storage unit that stores a condition table indicates conditions for which a preceding job can be interrupted by an interrupt job, and a system-control unit that references the condition table, and when the preceding job can be interrupted, sets a printing order so that printing of the interrupt job is inserted into the printing order of the preceding job.

INCORPORATION BY REFERENCE

This application is based on and claims the benefit of priority from Japanese Patent Application No. 2016-077925 filed on Apr. 8, 2016, the contents of which are hereby incorporated by reference.

BACKGROUND

The present disclosure relates to an image-forming apparatus with an interrupt printing function.

In an image-forming apparatus that is an MFP such as a printer, multifunction printer, copier and the like, there are models in which it is possible to register printing jobs from user terminals via a network. Moreover, the image-forming apparatus generally executes a printing process for printing jobs that do not have a priority setting in the order of being input.

Incidentally, there are also printing jobs such as printing one page on one side (hereafter, referred to as a simple job). Even in the case of such a simple job, by performing printing processes in the order of input, a later printing job must wait for a previously registered printing job to finish, which is inconvenient.

In a typical image-forming apparatus, in order to eliminate such an inconvenience, there are switch back means for turning over the paper, standby means for causing paper to wait in a stopped state on the paper-refeed transporting path, and control means for performing control of each of these means. When mixing paper of different paper sizes, and continuously performing reverse output and double-sided copying, the control means sets the space between the preceding paper and the following paper to be equal to or longer than the length in the transporting direction of the preceding paper.

SUMMARY

The image-forming apparatus of the present disclosure includes a printer unit, a first transporting path, a second transporting path, a storage unit and a system-control unit. The printer unit prints on paper. The first transporting path passes by the printer unit. The second transporting path branches off from the first transporting path and moves paper that has been turned over from front to back further upstream than the printer unit of the first transporting path. The storage unit stores a condition table that, based on the premise that paper is transported by the second transporting path, indicates conditions for which a preceding job that is double-sided printing can be interrupted by an interrupt job that is single-sided printing. The system-control unit, when the interrupt printing job is set, references the condition table, and when the preceding job can be interrupted, sets a printing order so that printing of the interrupt job is inserted into the printing order of the preceding job.

DETAILED DESCRIPTION

In the following, embodiments of the image-forming apparatus of the present disclosure will be explained with reference toFIG. 1toFIG. 12. The image-forming apparatus that will be explained below as an example is an MFP, which is a multifunctional peripheral having, for example, a printing function, a copy function, a FAX function and a data receiving/transmitting function via a network.

First, as illustrated inFIG. 1, a paper-supply unit110, a printer unit120, paper-detection sensors140to142, and a transporting unit150are installed inside a main unit101of a MFP100. The reference number160indicates a paper-supply unit, and reference numbers161and162indicate paper-output trays.

The paper-supply unit110houses plural paper-supply cassettes112that are able to store various kinds of paper111having different paper sizes and paper types. Moreover, a paper-supply roller113is provided in each of the paper-supply cassettes112. A paper-supply roller113feeds paper111from a paper-supply cassette112to a common transporting path110athat is provided in each paper-supply cassette112.

The printer unit120includes an image-forming unit (M)121, an image-forming unit (C)122, an image-forming unit (Y)123and an image-forming unit (B)124that have a photosensitive drum, a developing device, a charging device, an exposing device and the like. The image-forming unit (M)121is for magenta, the image-forming unit (C)122is for cyan, the image-forming unit (Y)123is for yellow, and the image-forming unit (B)124is for black.

Moreover, the printer unit120has primary transfer rollers125a,to125d,a drive roller126, a follower roller127, an intermediate-transfer belt128, a secondary-transfer roller129and a fixing unit130. The image-forming unit (M)121, the image-forming unit (C)122, the image-forming unit (Y)123, and the image-forming unit (B)124form toner images on the photosensitive drums by charging, exposing and developing processes based on printing data. The primary-transfer rollers125ato125dtransfer the toner images on the photosensitive drums to the intermediate-transfer belt128that is placed around the drive roller126and follower roller127. The secondary-transfer roller129presses the paper111from the rear-surface side and transfers the toner image on the intermediate-transfer belt128to the front-surface side of the paper111.

The fixing unit130has a heating roller131and a pressure roller132. The heating roller131applies heat from a heat source131athat is controlled by a heat-source control unit to the paper111. The pressure roller132presses the paper111to the heating-roller131side. The pressure force of the pressure roller132is adjusted by a pressure-adjustment mechanism132a.Then, the fixing unit130applies pressure by way of the pressure roller132and heat by way of the heating roller131to the paper111to which the toner image has been transferred by the drive roller126and secondary-transfer roller129. As a result, the toner image is fixed to the paper111. The pressure-adjustment mechanism132aincludes a pressure member that presses the pressure roller132in a direction toward the heating roller131, a spring, and a drive unit such as a stepping motor, and by moving the pressure member by operating the drive unit, adjusts the pressure of the pressure roller132.

The paper-detection sensors140to142detect the paper111on the transporting paths150a,150b.In other words, the paper-detection sensor140detects paper111on the transporting path150athat has passed the fixing unit130. The paper-detection sensor141detects paper111on the transporting path150athat has passed a transporting-roller unit153. The paper-detection sensor142detects paper111on the transporting path150b.

The transporting unit150has transporting-roller units151to159, and switching tabs150c,150d.Each of the transporting-roller units151to159has a drive roller and a follower roller. The transporting-roller units151to154are arranged on the transporting path150athat extends from the common transporting path110ato the paper-output tray161. The transporting-roller unit155is arranged on the transporting path150athat extends to the paper-output tray162. Paper111that has undergone a printing process of a preceding job and paper111that has undergone a printing process of an interrupt printing job are switched by the switching tab150cand transported to either the paper-output tray161or162. In other words, when the output destination of paper111that has undergone a printing process of a preceding job is paper-output tray161, the output destination of paper111that has undergone a printing process of an interrupt printing job becomes paper-output tray162. In this way, it is easy to check the paper111that has been printed. The secondary-transfer roller129and the fixing unit130of the printer unit120that was described above are arranged between the transporting units151to152.

When single-sided printing is set, the transporting-roller units151to154transport the paper111from the common transporting path110ain the direction of arrow a along the transporting path150a.While the paper is being transported in the direction of arrow a, the secondary-transfer roller129of the printer unit120transfers a toner image to the paper111, and the heating roller131and the pressure roller132of the fixing unit130fix the toner image. Then, when the paper-output tray161is set as the output destination, for example, the paper111that has undergone the printing process is outputted to the paper-output tray161. Moreover, when the paper-output tray162is set as the output destination, for example, the paper111that has undergone the printing process is outputted, by the switching tab150cswitching the transporting path, to the paper-output tray162.

However, when double-sided printing is set, by the switching tab150dswitching the transporting path, the paper to which a toner image was fixed to the front side by the fixing unit130is moved to the transporting path150bside. Here, the transporting-roller units156to159are arranged on the transporting path150bthat bypasses the transporting path150abetween the transporting-roller unit151and152. The transporting path150bincludes a switchback mechanism in which the transporting-roller unit156causes the paper111to be switched back. Then, when moving the paper111from the transporting path150bside to the transporting path150aside (downstream side of the printer unit120), the front and back of the paper is reversed. Moreover, while the paper111is being transported in the direction of arrow a, the secondary-transfer roller129of the printer unit120transfers a toner image to the back surface of the paper111, and the heating roller131and the pressure roller132of the fixing unit130fix the toner image. Then, when the paper-output tray161is set as the output destination for example, the paper111that has undergone the printing process is outputted to the paper-output tray161. Moreover, when the paper-output tray162is set as the output destination for example, by the switching tab150cswitching the transporting path, the paper111that has undergone the printing process is outputted to the paper-output tray162.

Next, referring toFIG. 2, an example of the configuration of the control system for the MFP100will be explained. The MFP100includes a control unit180that controls the scanner unit170, the printer unit120, the FAX unit171, the I/F172, the paper-detection sensors140to142, the panel unit173, and the HDD174.

The scanner unit170is a device that converts an image of a document that is read by an image sensor to digital image data, and inputs that data to the control unit180. The printer unit120is a device that prints an image on paper111based on printing data that is outputted from the control unit180. The FAX unit171is a device that transmits data that is outputted from the control unit180to a facsimile of another party by way of telephone lines, and receives data from a facsimile of another party and inputs that data to the control unit180.

The I/F172is a device such as a network interface card that receives communication from another user terminal, a content server, a web server and the like via a network such as an in-house LAN, the Internet and the like. The paper-detection sensors140to142detect paper111that is on a transporting path150a,150bas described above. The panel unit173is a device such as a touch panel that performs a display for the printing function, copy function, FAX function, data transmitting/receiving function via a network, and for various settings of the MFP100. The HDD174is a storage device for storing application programs and the like for providing the various functions of the MFP100. Moreover, the HDD174has a user box for registering printing jobs that are received from a user terminal via a network.

The control unit180is a processor for executing an image-forming program and control program for controlling the overall operation of the MFP100. The control unit180includes a scanner-control unit181, a printer-control unit182, a FAX-control unit183, a communication-control unit184, RAM185, ROM186, an image-processing unit187, a sensor-control unit188, a transporting-control unit189, a panel-operation-control unit190, an HDD-control unit191and a system-control unit192. Moreover, these are connected to a database193.

The scanner-control unit181controls the reading operation by the scanner unit170. The printer-control unit182controls the printing operation by the printer unit120. The FAX-control unit183controls the data transmitting/receiving operation by the FAX unit171. The communication-control unit184performs control of transmitting or receiving data and the like via a network and by way of the I/F172.

The RAM185is a work memory for executing programs. Moreover, the RAM185stores printing data that has undergone image processing by the image-processing unit187. The ROM186stores control programs for performing operation checks and the like for all of the units. The image-processing unit187performs image processing on image data that is read by the scanner unit170, for example. Moreover, the image-processing unit187performs image processing on printing jobs that are registered in the HDD174.

The sensor-control unit188controls the detection operation by the paper-detection sensors140to142. The transporting-control unit189, when single-sided printing is set, drives the transporting-roller units151to154in the forward direction (direction for transporting the paper111along the transporting path150ain the direction of arrow a), and outputs the paper111to the paper-output tray161, for example. Moreover, the transporting-control unit189, by switching by the switching tab150c,drives the transporting-roller unit155in the forward direction, and outputs the paper111to the paper-output tray162, for example. Moreover, the transporting-control unit189, when double-sided printing is set, drives the transporting-roller units151to154in the forward direction, and drives the transporting-roller units156to159in the opposite direction (direction that transports the paper111in the direction of arrow b). Furthermore, the transporting-control unit189, switches the switching tab150dand causes the paper111to be transported in the direction of arrow b. Moreover, the transporting-control unit189switches the switching tab150dand causes the paper111that has been printed on both sides to be output to the paper-output tray161. The transporting-control unit189, when interrupt printing is set, switches the switching tab150cand causes the paper111for which interrupt printing has finished to be output to the paper-output tray162, for example. As a result, paper111for which printing is performed for a preceding job, and paper111that is printed by interrupt printing can be divided and output to paper-output tray161or162. The output destination for the paper111is set according to a setting performed by way of the panel unit173.

The panel-operation-control unit190controls the display operation by the panel unit173. Moreover, the panel-operation-control unit190, by way of the panel unit173, receives the start or the like for printing (single-sided printing, double-sided printing, and the like), copying, a FAX, data transmitting/receiving via a network and the like. Furthermore, the panel-operation unit190, by way of the panel unit173, receives the setting for interrupt printing. The HDD-control unit191controls reading and writing of data to the HDD174.

The system-control unit192controls cooperative operation of each of the units. In other words, the system-control unit192, when single-sided printing or double-sided printing is set by way of the panel unit173, mainly causes the transporting-control unit189to drive according to single-sided printing or double-sided printing. Moreover, as will be described in more detail later, when a preceding printing job is set as double-sided printing, and interrupt printing is set for a printing job that is set for one-page of single-sided printing (hereafter, referred to as a simple job), the system-control unit192determines conditions such as the paper size, number of sheets to be printed, sheet batch number and the like for the preceding job, and starts single-sided printing for the simple job at timing when interrupting is possible. Furthermore, the system-control unit192switches the switching tab150cby way of the transporting-control unit189so that paper111for which the printing process for a preceding job is finished is outputted to the paper-output tray161, for example. The system-control unit192also switches the switching tab150cby way of the transporting-control unit189so that paper111for which the printing process for a simple job is finished is outputted to the paper-output tray162, for example. The system-control unit192controls switching of the switching tabs150c,150dbased on detection results from the paper-detection sensors140and141.

Next, referring toFIG. 3, a condition table that gives conditions for a preceding job that can be interrupted by a simple job will be explained. First, in the condition table200, the transporting pattern for the paper111that is indicated by N Sheet Batch (N is a positive integer) and the contents of a preceding job that can be interrupted are given. The transporting pattern is set between 1 Sheet to 4 Sheets. Here, 1 Sheet to 4 Sheets is divided according to the paper size and the printing unit of the image data that is stored in a video buffer (the printing unit indicates a page that will be printed on the front and back surface of one sheet of paper111). When taking into consideration only the paper size, 1 Sheet Batch indicates size A2 for example, 2 Sheet Batch indicates size A4 for example, 3 Sheet Batch indicates size A4 for example, and 4 Sheet Batch indicates size B5 for example. However, when the speed for generating image data from printing data becomes slow, the Sheet Batch (transporting pattern) may be set to a smaller number N for the paper sizes above. Moreover, in the present embodiment, in the case of a 1 Sheet Batch, interrupt is set as not possible. In the case of 2 Sheet Batch and 3 Sheet Batch, when 2-page double-sided printing is set, interrupt is set as possible. Moreover, in the case of a 4 Sheet Batch, when 2-page double-sided printing is set or 4-page double-sided printing is set, interrupt is set as possible.

As a simple job that interrupts a preceding job, a 2 Sheet Batch in which 1-page single-sided printing is performed is possible. The pages of the preceding job, in addition to pages that are included in the printing data, includes blank pages of paper111that have been printed. Therefore, when performing double-sided printing of printing data when the number of pages included in the printing data is odd, the portion of the last page of blank pages of printed matter is included in the number of pages given as the contents of a preceding job that can be interrupted in the condition table200.

Moreover, in the case in which the preceding job is 2-page double-sided printing in a 4 Sheet Batch, in addition to 1-page single-sided printing as a simple job that interrupts the preceding job, 2-page single-sided printing is also possible. Therefore, in the condition table200, in addition to the transporting pattern and the contents of the preceding job that can be interrupted, the number of pages of single-sided printing (or the number of sheets of paper111) that can interrupt can be set as a simple job.

The condition table200that gives conditions of a preceding job that can be interrupted by a simple job can be stored in the RAM185or HDD174. Moreover, the system-control unit192determines whether interrupt by a simple job is possible by referencing the condition table200when interrupt printing has been set by way of the panel unit173.

Next, the printing order in the conditions of a preceding job that can be interrupted by a simple job will be explained. First,FIGS. 4A to 4EandFIGS. 5F to 5Hillustrate the printing order in the condition of a 3 Sheet Batch when the preceding job is 6-page double-sided printing. The printing order in the case of a 3 Sheet Batch, as illustrated inFIG. 4A, is such that printing is started from the second page and ends with the fifth page. As a result, the first page and the second page are printed on the first sheet of paper111a,the third page and the fourth page are printed on the second sheet of paper111b,and the fifth page and sixth page are printed on the third sheet of paper111c.

In other words, after the second page is printed on the front surface of the first sheet of paper111aas illustrated inFIG. 4B, the first sheet of paper111ais moved to the transporting path150bside that branches off from the transporting path150aas illustrated inFIG. 4C. At the same time as this, the fourth page is printed on the front surface of the second sheet of paper111b.Continuing, as illustrated inFIG. 4D, after the second sheet of paper111bis moved to the transporting path150bside, the first sheet of paper111athat has been turned over from front to back in the transporting path150bis moved from the junction between the transporting path150aand the transporting path150bto the transporting path150a.As a result, the first page is printed on the back surface. Moreover, as illustrated inFIG. 4E, at the same time that the first sheet of paper111ais outputted, the sixth page is printed on the front surface of the third sheet of paper111c.After that, as illustrated inFIG. 5F, the third page is printed on the back surface of the second sheet of paper111b,and as illustrated inFIG. 5G, the fifth page is printed on the back surface of the third sheet of paper111c.As illustrated inFIG. 5H, printing ends. The junction between the transporting path150aand the transporting path150bis on the upstream side from the printer unit120of the transporting path150a,and more specifically, is upstream from the secondary transfer roller129of the transporting path150a,and even more specifically, is just before the transporting-roller unit151(refer toFIG. 1) of the transporting path150a.

Next, referring toFIGS. 6A to 6E, interrupt printing in the condition of a 3 Sheet Batch when the preceding job is 2-page double-sided printing will be explained. First, as illustrated inFIG. 6A, the paper111A of a simple job interrupts and is inserted after the second page of the first sheet of paper111ais printed. In other words, as illustrated inFIG. 6B, after the second page is printed on the front surface of the first sheet of paper111a,as illustrated inFIG. 6C, the first sheet of paper111ais then moved to the transporting path150bthat branches off from the transporting path150a.At the same time as this, the image of the simple job is printed on the front surface of the paper111A of the simple job. Next, as illustrated inFIG. 6D, at the same time that the paper111A of the simple job is outputted, the first sheet of paper111athat has been turned over from front to back in the transporting path150bis moved to the transporting path150afrom the junction between the transporting path150aand the transporting path150, and the first page is printed on the back surface of the paper111a.Then, as illustrated inFIG. 6E, the first sheet of paper111ais outputted and printing ends. As a result, when the first sheet of paper111ais on the transporting path150b,interrupt printing is executed on the paper111A of the simple job, so the job is continued to the first sheet of paper111awithout stopping.

The printing order in a 3 Sheet Batch condition when the preceding job is 4-page double-side printing is: the second page to the fourth page to the first page to the third page. The printing order in the case of an interrupt by a simple job becomes: the second page to the fourth page to the first page to the simple job (interrupt) to the third page. Moreover, as illustrated inFIG. 4A, the printing order in a 3 Sheet Batch condition when the preceding job is 6-page double-sided printing is: the second page to the fourth page to the first page to the sixth page to the third page to the fifth page. The printing order in the case of an interrupt by a simple job becomes: the second page to the fourth page to the first page to the sixth page to the third page to the simple job (interrupt) to the fifth page.

Next, referring toFIGS. 7A to 7EandFIGS. 8G to 8I, the printing order in a 4 Sheet Batch condition when the preceding job is 8-page double-sided printing will be explained. First, as illustrated inFIG. 7A, the printing order in the case of a 4 Sheet Batch is set so that printing starts from the second page and printing ends at the seventh page. As a result, the first page and the second page are printed on the first sheet of paper111a,the third page and the fourth page are printed on the second sheet of paper111b,the fifth page and the sixth page are printed on the third sheet of paper111cand the seventh page and the eighth page are printed on the fourth sheet of paper111d.

In other words, as illustrated inFIG. 7B, after the second page is printed on the front surface of the first sheet of paper111a,as illustrated inFIG. 7C, the first sheet of paper111ais moved to the transporting path150bside that branches off from the transporting path150a.At the same time as this, the fourth page is printed on the front surface of the second sheet of paper111b.Continuing, as illustrated inFIG. 7D, after the second sheet of paper111bis moved to the transporting path150bside, the sixth page is printed on the front surface of the third sheet of paper111c.Next, as illustrated inFIG. 7E, at the same time that the third sheet of paper111cis moved to the transporting path150bside, the first sheet of paper111athat has been turned over from front to back on the transporting path150bis moved to the transporting path150aside from the junction between the transporting path150aand the transporting path15b,and the first page is printed on the back surface of the paper111a.

Moreover, as illustrated inFIG. 8F, at the same time that the first sheet of paper111ais outputted, the eighth page is printed on the front surface of the fourth sheet of paper111d.After that, as illustrated inFIG. 8G, the third page is printed on the back surface of the second sheet of paper111b,then as illustrated inFIG. 8H, the fifth page is printed on the back surface of the third sheet of paper111c,and as illustrated inFIG. 8I, the seventh page is printed on the back surface of the fourth sheet of paper111d,after which printing ends. InFIG. 8F, when the eighth page is printed on the front surface of the fourth sheet of paper111d,the second sheet of paper111bwaits on the transporting path150b,printing of the second sheet of paper111bcontinues after printing of the fourth sheet of paper111d,so the printing job is continuous without stopping.

Next, referring toFIGS. 9A to 9E, interrupt printing in a 4 Sheet Batch condition when the preceding job is 2-page double-sided printing will be explained. First, the paper111A of a simple job interrupts and is inserted after the second page has been printed on the first sheet of paper111a.In other words, as illustrated inFIG. 9B, after the second page is printed on the front surface of the first sheet of paper111a,the first sheet of paper111ais moved to the transporting path150bside that branches off from the transporting path150aas illustrated inFIG. 9C. At the same time as this, the image of the simple job is printed on the front surface of the paper111A of the simple job. Continuing, as illustrated inFIG. 9D, at the same time that the paper111A of the simple job is outputted, the first sheet of paper111athat is turned over from front to back on the transporting path150bis moved to the transporting path150aside from the junction between the transporting path150aand the transporting path150b,and the first page is printed on the back surface of the paper111a.Then, as illustrated inFIG. 9E, the first sheet of paper111ais outputted and printing ends. As a result, interrupt printing on the paper111A of the simple job is executed while the first sheet of paper111ais on the transporting path150b,so the job continues to the first sheet of paper111awithout stopping.

Next, referring toFIGS. 10A to 10EandFIGS. 11F and 11G, interrupt printing in a 4 Sheet Batch condition when the preceding job is 4-page double-sided printing will be explained. First, as illustrated inFIG. 10A, the printing paper111A for a simple job interrupts and is inserted after the fourth page is printed on the second sheet of paper111b.In other words, as illustrated inFIG. 10B, after the second page is printed on the front surface of the first sheet of paper111a,the first sheet of paper111ais moved to the transporting path150bside as illustrated inFIG. 10C. At the same time as this, after the fourth page is printed on the front surface of the second sheet of paper111b,the second sheet of paper111bis moved to the transporting path150bside as illustrated inFIG. 10D. At the same time as this, the simple job is printed on the front surface of the paper111A for the simple job.

Continuing, as illustrated inFIG. 10E, at the same time that the paper111A for the simple job is outputted, the first sheet of paper111athat is turned over from front to back is moved to the transporting path150a,and the first page is printed on the back surface of the first sheet of paper111a.Moreover, as illustrated inFIG. 11F, at the same time that the first sheet of paper111ais outputted, the third page is printed on the back surface of the second sheet of paper111b,after which as illustrated inFIG. 11G, the second sheet of paper111bis outputted and printing ends. As a result, as illustrated inFIG. 10D, when the first sheet of paper111aand the second sheet of paper111bare on the transporting path150b,interrupt printing on the paper111A of the simple job is executed, so processing of the preceding job continues without being stopped.

The printing order in a 4 Sheet Batch condition when the preceding job is 2-page double-sided printing and a simple job that is 2-page single-sided printing interrupts becomes: the second page to the simple job (interrupt for the first page) to the simple job (interrupt for the second page) to the first page. As described above, after the front surface of the last sheet of paper111of a preceding job that is double-sided printing (in other words, the last sheet of paper111that is supplied to the transporting path150aof the sheets of paper111that are used in the printing of the preceding job, for example, the first sheet in the case of 2-page double-sided printing in a 4 Sheet Batch, or the second sheet in the case of 4-page double-sided printing) is printed and until the back surface of the first sheet of paper111of the preceding job (in other words, the first page of the preceding job) is printed, new paper111that is not used for printing of the preceding job can be supplied to the transporting path150a,and the number of pages of single-sided printing that can be printed can interrupt as a simple job. In other words, when the number of sheets of printing of a preceding job that is double-sided printing (half of the number of pages) is less than the number of sheets of paper111that can be transported at the same time on the portion of the transporting path150afrom the junction with the transporting path150bto the branching point and on the transporting path150b(except for the sheets of paper111that have passed the transfer unit after being turned over from front to back (portion where the secondary transfer roller129faces the intermediate transfer belt128)), it is possible for a simple job that is single-sided printing to interrupt when less than the number of sheets obtained by subtracting the number of sheet of printing of the preceding job from the number of sheets of paper111that can be transported at the same time.

This also the same for a transporting path that is a 5 Sheet Batch or greater, or in other words, for a transporting pattern in which the number of sheets of paper111that can be newly supplied to the transporting path150aafter printing on the front surface of the first sheet of printing paper111(in other words, the second page of the preceding job) and until printing the back surface of the first sheet of paper111(in other words, the first page of the preceding job) is three sheets or more. The system-control unit180, based on conditions such as described above under which a simple job can be printed, sets the printing order so that printing of simple job is performed. More specifically, when a simple job can interrupt a preceding job, the system-control unit180sets the printing order so that after the last printing paper111that is used for printing of the preceding job is supplied to the transporting path150a,the new printing paper111that is used for printing of the simple job is supplied to the transporting path150aand printed.

However, in the case of a 2 Sheet Batch, after printing on the front surface of the (2n−1)th sheet of paper111(n is a positive integer) (in other words, the (4n−2)th page of the preceding job) and until the printing of the back surface of the (2n−1)th sheet of paper111(in other words the (4n−3)th page of the preceding job), the number of pages of new paper111for single-sided printing that can be supplied to the transporting path150aand printed can interrupt as a simple job. Here, the printing order in a 2 Sheet Batch condition becomes: the second page to the fourth page to the first page to the third page to the sixth page to the eighth page to the fifth page to the seventh page and so on. For example, in a 2 Sheet Batch condition when the preceding job is 2-page double-sided printing, the printing order when a simple job that is 2-page single-sided printing interrupts becomes: the second page to the simple job (interrupt) to the first page. Moreover, in a 2 Sheet Batch condition when the preceding job is 6-page double-sided printing, the printing order when a simple job that is 2-page single-sided printing becomes: the second page to the fourth page to the first page to the third page to the sixth page to the simple job (interrupt) to the fifth page.

Next, referring toFIG. 12, interrupt processing by the MFP100will be explained. In the following, the case of interrupt printing of a simple job after a preceding job will be explained.

The system-control unit192determines whether or not interrupt printing is set.

In this case, the system-control unit192waits for a notification from the panel-operation control unit190(step S101: NO), and when a notification indicating that interrupt printing is set is received from the panel-operation control unit190, the system-control unit192determines that interrupt printing is set (step S101: YES), and moves to step S102.

The system-control unit192references the condition table described above that gives the conditions for a preceding job for which interrupt by a simple job is possible, and determines whether or not the preceding job can be interrupted.

In this case, when the preceding job is a 1 Sheet Batch, the system-control unit192determines that interrupt by a simple job is not possible (step S102: NO), and moves to step S109.

However, when the preceding job is a 3 Sheet Batch, the system-control unit192determines that interrupt by a simple job is possible (step S102: YES), and moves to step S103.

The system-control unit192sets the printing order for the simple job. In this case, as illustrated inFIG. 6Afor example, in a 3 Sheet Batch condition when the preceding job is a 2-page double-sided printing, the system-control unit192sets the printing order so that simple job interrupts after the second page of the preceding job is printed.

Moreover, as illustrated inFIG. 9Afor example, in a 4 Sheet Batch condition when the preceding job is 2-page double-sided printing, the system-control unit192sets the printing order so that the simple job interrupts after the second page of the preceding job is printed.

Furthermore, as illustrated inFIG. 10Afor example, in a 4 Sheet Batch condition when the preceding job is 4-page double-sided printing, the system-control unit192sets the printing order so that the simple job interrupts after the fourth page of the preceding job is printed.

After setting the printing order of the simple job, the system-control unit192gives an instruction to start printing.

In this case, the system-control unit192gives an instruction to the image-processing unit187to perform image processing for the preceding job and the simple job. After printing data that has undergone image processing by the image-processing unit187is stored in the RAM185, the system-control unit192gives an instruction to the transporting-control unit189to transport paper111, and gives an instruction to the printer-control unit182to print.

The printer-control unit182starts printing on the paper111based on the printing data that is stored in the RAM185.

The system-control unit192determines whether or not it is time for the simple job.

Here, as illustrated inFIG. 6Afor example, in a 3 Sheet Batch condition when the preceding job is 2-page double-sided printing, the system-control unit192, determines that it is not the time for the simple job when the second page is being printed on the front surface of the first sheet of paper111aas illustrated inFIG. 6B(step S106: NO).

However, when printing of the second page on the front surface of the first sheet of paper111ais finished as illustrated inFIG. 6C, the system-control unit192determines that it is time for the simple job (step S106: YES), and moves to step S107.

Moreover, in a 4 Sheet Batch condition when the preceding job is 2-page double-sided printing as illustrated inFIG. 9Afor example, the system-control unit192determines that it is not time for the simple job when the second page is being printed on the front surface of the first sheet of paper111aas illustrated inFIG. 9B(step S106: NO).

However, when printing of the second page on the front surface of the first sheet of paper111ais finished as illustrated inFIG. 9C, the system-control unit192determines that it is time for the simple job (step S106: YES), and moves to step S107.

Furthermore, in a 4 Sheet Batch condition when the preceding job is 4-page double-sided printing as illustrated inFIG. 10Afor example, the system-control unit192determines that it is not time for the simple job when the second page is being printed on the front side of the first sheet of paper111aas illustrated inFIG. 10B, and when the fourth page is being printed on the front surface of the second sheet of paper111bas further illustrated inFIG. 10C(step S106: NO).

However, after printing of the fourth page on the front surface of the second sheet of paper111bis finished as illustrated inFIG. 10D, the system-control unit192determines that it is time for the simple job (step S106: YES), and moves to step S107.

The system-control unit192gives an instruction to print the simple job. Here, as illustrated inFIG. 6Afor example, in a 3 Sheet Batch condition when the preceding job is 2-page double-sided printing, after the first sheet of paper111afor which printing is complete is moved to the transporting path150bside as illustrated inFIG. 6C, the system-control unit192executes printing on the paper111A of the simple job.

Moreover, as illustrated inFIG. 9Afor example, in a 4 Sheet Batch condition when the preceding job is 2-page double-sided printing, after the first sheet of paper111afor which printing is complete is moved to the transporting path150bside as illustrated inFIG. 9C, the system-control unit192executes printing on the paper111A of the simple job.

Furthermore, as illustrated inFIG. 10Afor example, in a 4 Sheet Batch condition when the preceding job is 4-page double-sided printing, after the second sheet of paper111bfor which printing is complete is moved to the transporting path150bside as illustrated inFIG. 10D, the system-control unit192executes printing on the paper111A of the simple job.

The system-control unit192determines whether or not printing is complete. In this case, the system-control unit192determines that printing is not complete when there is no printing-complete notification from the printer-control unit182(step S108: NO).

However, when there is a printing-complete notification from the printer-control unit182, the system-control unit192determines that printing is complete (step S108: YES), and ends processing.

When it is determined in step S102that a preceding job cannot be interrupted, the system-control unit192gives an instruction to perform normal printing, and moves to step S108.

In this case, when the preceding job is a 1 Sheet Batch, it is not possible to interrupt the preceding job, so after printing of the preceding job is complete, the system-control unit192gives an instruction to print the simple job.

The image-forming apparatus of the present disclosure includes a transporting path150a(first transporting path) that passes by the printer unit120, and a transporting path150b(second transporting path) for moving paper111, which has been branched off from the transporting path150a(first transporting path) and turned over from front to back, further to the upstream side than the printer unit120of the transporting path150a(first transporting path). When an interrupt job is set, presuming that transporting will be performed on the transporting path150b(second transporting path), the system-control unit192references the condition table200that indicates conditions for preceding jobs that are double-sided printing and that can be interrupted by an interrupt job that is single-sided printing, and when a preceding job can be interrupted, sets the printing order so that printing of the interrupt job is inserted in the printing order of the preceding job. As a result, during processing of a simple job (interrupt job), the paper of the preceding job is positioned on the transporting path150b(second transporting path) side, and after processing of the simple job (interrupt job) is finished, processing of the preceding job can be continued, so it is possible to prevent a drop in the processing speed even when a preceding job is interrupted by a simple job (interrupt job).

In a typical image-forming apparatus, when an interrupting printing instruction is inputted during continuous copying, it is possible to form an image on paper after the printing interrupt by causing the preceding paper that has been printed in the copying process to wait on a paper-refeed transporting path.

Incidentally, in the image-forming apparatus, there is a problem in that image formation on the preceding paper is restarted after the preceding paper is caused to wait on the paper-refeed transporting path, so there is a drop in the processing speed by the amount that the preceding paper was caused to wait.

However, with the image-forming apparatus of the present disclosure, it is possible for processing of the preceding job to continue after processing of the interrupt job is finished, so it is possible to prevent a drop in the processing speed even when a preceding job is interrupted by an interrupt job.

In the present embodiment, the case was explained in which, when interrupt printing by a simple job is set by way of the panel unit173and the preceding job can be interrupted, the system-control unit192causes the simple job to interrupt the preceding job. Not being limited to this, when a user ID that is included in a simple job is registered in the MFP100, interrupt processing by that simple job may also be performed preferentially.