JP2012058426A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that maintains, as much as possible, the productivity of printing paper in print processing where different types of printing paper is used.SOLUTION: In the case of print processing of an image forming apparatus 1 where different types of printing paper is used, a tandem system management part 190 determines on which of even-numbered pages or odd-numbered pages a first image forming unit 100 and a second image forming unit 200 perform print processing based on modes set in the respective units.

Description

  The present invention relates to an image forming apparatus.

2. Description of the Related Art Conventionally, image forming apparatuses such as printers and copiers that perform printing processing on one side or both sides of a sheet are known.
In the image forming apparatus, it is possible to switch between a color mode for performing color printing processing and a monochrome mode for performing monochrome printing processing, and an image forming unit for performing printing processing on one side of a sheet is provided in the front and rear stages. There is a connected tandem image forming apparatus. The image forming apparatus having a tandem configuration performs a printing process on both sides of a sheet by performing a printing process on one side in the preceding stage and a printing process on the opposite side of the one side in the subsequent stage.

An image forming apparatus having such a tandem configuration is capable of printing a plurality of print sheets in response to a print instruction (print job execution instruction transmitted from an external apparatus such as a PC or a user via a print button). Perform the printing process. In addition, a color image and a monochrome image need to be printed on one side of the sheet, and a monochrome print process needs to be performed on the opposite side of the sheet. In some cases, mixed printing paper (hereinafter, mixed printing paper) is included. In this case, the image forming apparatus can perform printing processing of the mixed printing paper by setting different modes for the respective image forming units.
However, if the setting is fixed so that each image forming unit prints on one side of the sheet opposite to the other side, the printing process is performed on a plurality of printing sheets including mixed printing sheets. In some cases, the mode of each image forming unit must be frequently changed. For example, in a state where the front image forming unit is set to print on one side of the paper in monochrome mode and the rear image forming unit is set to print on the opposite side of the paper in color mode, This is the case, for example, when printing processing is performed on mixed printing paper that requires color printing on one side and monochrome printing on the other side.
In such a case, since it takes time to change the mode setting of each image forming unit, the productivity of printing paper in the printing process decreases.

  Therefore, for example, each image forming unit performs the printing process on which side of the sheet is opposite to the one side of the sheet. In performing the printing process on the remaining amount of toner of each image forming unit and the opposite side of the one side, for example. An image forming apparatus having a tandem configuration that is determined based on a required toner consumption amount is known (see Patent Document 1). According to the image forming apparatus described in Patent Document 1, it is possible to appropriately change which side of each sheet of the image forming unit performs the printing process on the opposite side of the sheet.

JP 2009-58623 A

  However, in the image forming apparatus described in Patent Document 1, each image forming unit performs a printing process on any surface in order to eliminate unevenness of the remaining amount of toner between the image forming units and reduce the toner replenishment work of the operator. It ’s just a change. In other words, even with the image forming apparatus described in Patent Document 1, it is possible to change the mode setting for each image forming unit when performing printing processing of a plurality of printing sheets including mixed printing sheets. The problem of decline is not solved.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image forming apparatus that, when performing printing processing of a plurality of printing papers including mixed printing papers, reduces the printing paper productivity in the printing processing as much as possible.

  In order to solve the above problems, an invention according to claim 1 is directed to an image forming apparatus capable of performing printing processing on both sides of a sheet by connecting an image forming unit capable of printing processing on one side of a sheet to a front stage and a rear stage. The image forming unit can be set by switching between a color mode for performing color printing on one side of the paper and a monochrome mode for performing monochrome printing on one side of the paper. When the printing process is performed on a plurality of printing sheets according to the printing instruction, the mixed printing sheets to be subjected to the color printing process on one side of the sheet and the monochrome printing process on the opposite side of the one side are the plurality of sheets. Each of the image forming units performs a printing process on either one side or the opposite side of the printing paper according to the mode set in the image forming unit. Characterized in that it comprises a control unit to determine.

  Therefore, the present invention can provide an image forming apparatus that, when performing printing processing of a plurality of printing papers including mixed printing papers, reduces the printing paper productivity in the printing processing as much as possible.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to the present invention. FIG. 2 is a diagram schematically showing an internal structure of a first image forming unit, a second image forming unit, and a paper feeding unit provided in the image forming apparatus of FIG. 1. FIG. 3 is a diagram schematically illustrating a first image forming unit provided in the first image forming unit of FIG. 2 and a second image forming unit provided in the second image forming unit. 1 is a block diagram of an image forming apparatus according to the present invention. FIG. 6 is a diagram illustrating a path followed by a printing paper when performing double-sided printing processing on the printing paper. FIG. 6 is a diagram illustrating a mode set in a first image forming unit and a second image forming unit and a surface on which the printing process is performed when printing processing is performed on each printing sheet according to a printing instruction. It is a figure which shows the key operator menu screen displayed on a display operation part. It is a figure which shows the tandem operation | movement setting screen displayed on a display operation part. FIG. 6 is a diagram for explaining image rotation and printing paper reversal processing, where (i) shows images formed on the surfaces corresponding to odd and even pages of printing paper, and (ii) shows the first image forming unit. When the odd-numbered page and the second image forming unit are set to perform the printing process for even-numbered pages, the orientation of the printing paper at the points P1 to P4 is shown in (ii). The orientations of the printing paper at the points P1 to P4 when the two-image forming unit is set to perform odd-numbered page printing processing are respectively shown. 4 is a flowchart for explaining print setting processing executed by the image forming apparatus according to the present invention. 5 is a flowchart for explaining print setting processing executed by the image forming apparatus according to the present invention. 4 is a flowchart for explaining print setting processing executed by the image forming apparatus according to the present invention. 4 is a flowchart for explaining print setting processing executed by the image forming apparatus according to the present invention.

  Hereinafter, the image forming apparatus according to the present embodiment will be described with reference to FIGS.

As shown in FIGS. 1 and 2, the image forming apparatus 1 according to the present embodiment includes a paper feeding unit 300, a first image forming unit 100 (front image forming unit), and a second image forming unit 200 (back stage). The image forming unit) and the post-processing unit 400 are arranged in a tandem configuration in series.
The image forming apparatus 1 applies the first image forming unit 100 and the second image forming unit 100 to the sheet fed from the sheet feeding unit 300 or the sheet feeding tray provided in the first image forming unit 100 or the second image forming unit 200. The image forming unit 200 performs color or monochrome printing processing, the post-processing unit 400 performs predetermined post-processing, and outputs (discharges) paper. Here, it is assumed that the first image forming unit 100 and the second image forming unit 200 each execute a printing process on one side of the paper. That is, when executing the printing process on both sides of the sheet, the first image forming unit 100 executes the printing process on one side of the sheet (or the opposite side of the one side), and the second image forming unit 200 is the opposite side of the sheet ( Alternatively, the printing process for one side) is executed.

As shown in FIG. 2, the paper feed unit 300 includes a paper feed unit tray 310 and a transport path T1.
The paper feed unit tray 310 includes a plurality of trays, and accommodates sheets identified on the basis of the amount of paper, size, and the like in each tray for each preset type. Then, the paper stored in the paper supply unit tray 310 is supplied to the first image forming unit 100 via the transport path T1 by the transport roller.

  As shown in FIG. 2, the first image forming unit 100 includes a first paper feed tray 110, a first print processing unit 120, transport path switching units 130 and 131, an ADF (Auto Document Feeder) 140, a scanner. 150, a display operation unit 160 (selection unit), and conveyance paths T2, T3, T4, and T5.

  The first paper feed tray 110 includes a plurality of trays, and stores the paper identified based on the amount of paper, the size, etc., in each tray for each type set by the user. The paper stored in the first paper feed tray 110 is transported by the transport roller to the transport path T3 via the transport path T2.

  The first print processing unit 120 forms a color or monochrome image by electrophotography on a sheet, and performs color or monochrome print processing by heating and fixing the formed image. The first print processing unit 120 includes a first image forming unit 121 including a photosensitive drum, a laser unit, and the like, a first fixing unit 122 including a fixing roller (a heating roller and a pressure roller), and the like. including.

  As shown in FIG. 3, the first image forming unit 121 includes a toner image generating unit 1211, an intermediate transfer belt 1212, a registration roller 1213, a guide plate 1214, and a secondary transfer belt 1215. The

The toner image generation unit 1211 includes a C (cyan) color toner image generation unit 1211a, an M (magenta) color toner image generation unit 1211b, a Y (yellow) color toner image generation unit 1211c, and a K (black) color toner image generation unit 1211d. , And is configured. The toner image generation unit 1211 includes a charging device, an exposure device, a photosensitive drum, and the like for each of the C color toner image generation unit 1211a to the K color toner image generation unit 1211d.
When the toner image generation unit 1211 generates a color toner image, the C color toner image generation unit 1211a to the K color toner image generation unit 1211d generate electrostatic images of CMYK colors based on the input image data. A latent image is formed on each photosensitive drum by a charging device or an exposure device. Further, the toner image generation unit 1211 forms a color toner image from the electrostatic latent images of CMYK colors on the respective photosensitive drums using a developing device or the like.
On the other hand, when forming a monochrome toner image, the toner image generation unit 1211 forms a K-color electrostatic latent image on the photosensitive drum by the K-color toner image generation unit 1211d based on the input image data. A toner image is formed on the photosensitive drum from the electrostatic latent image by a developing device or the like.
Further, the toner image generation unit 1211 applies a driving force from a motor (not shown) or the like, so that the toner image generation unit 1211 is in close contact with the intermediate transfer belt 1212 and is separated from the C color toner image generation units 1211a to 1211a. Switching can be performed for each generation unit 1211d. Of course, it is possible to provide a configuration that can switch between a state of being in close contact with the toner image generation unit 1211 and a state of being separated from the intermediate transfer belt 1212 side.

The intermediate transfer belt 1212 is configured to be rotatable in the direction of the arrow (solid line) in FIG. The intermediate transfer belt 1212 rotates in a state of being in close contact with the toner image generation unit 1211 (C color toner image generation unit 1211a to K color toner image generation unit 1211d), so that the color or color formed by the toner image generation unit 1211 is increased. A monochrome toner image is intermediately transferred. The intermediate transfer belt 1212, together with the secondary transfer belt 1215, transfers a toner image onto a sheet, and carries the sheet toward the first fixing unit 122.
The guide plate 1214 guides the sheet fed from the sheet feeding unit 300 or the first sheet feeding tray 110 so as to be conveyed toward the registration roller 1213 or the intermediate transfer belt 1212. The registration roller 1213 aligns the leading edge of the sheet conveyed by the guide plate 1214. Then, the registration roller 1213 carries the sheet toward the intermediate transfer belt 1212 at a timing when the intermediate transfer belt 1212 transfers the toner image onto the sheet. The secondary transfer belt 1215 presses the intermediate transfer belt 1212 to transfer the toner image on the intermediate transfer belt 1212 to a sheet.

  The first fixing unit 122 includes a plurality of fixing rollers that rotate in the forward direction with respect to the sheet conveyance direction and a fixing belt that winds the fixing rollers. Then, the first fixing unit 122 heats and presses the sheet carried into the nip portion of the first fixing unit 122 to heat and fix the toner image on the sheet.

The conveyance path switching unit 130 is either a sheet that is carried into the conveyance path switching unit 130 via the conveyance path T1 or a sheet that is carried into the conveyance path switching unit 130 via the conveyance path T2. The transport path is switched so that the sheet of paper is transported to the transport path T3.
The transport path switching unit 131 transports the paper carried into the transport path switching unit 131 via the transport path T3 to the transport path T5 via the transport path T4 or without passing through the transport path T4. Whether to transport to the transport path T5 is switched. Here, when the sheet passes through the conveyance path T4, the sheet is conveyed to the conveyance path T5 in a state where the front and back sides of the sheet are reversed.

The ADF 140 automatically conveys the originals stacked on the original placement tray to the scanner 150 in order from the top.
The scanner 150 performs a reading process of the document conveyed by the ADF 140. Specifically, the scanner 150 scans an original with light emitted from a light source, forms an image of reflected light with a CCD (Charge Coupled Device), and performs photoelectric conversion. Then, the scanner 150 acquires a document image from a document read by photoelectric conversion.

  The display operation unit 160 includes an LCD (Liquid Crystal Display), a touch panel provided so as to cover the LCD, an operation key group such as various operation keys and operation buttons, and the like. The display operation unit 160 displays various operation screens and various processing results on the LCD according to instructions from the tandem system management unit 190 described later. Further, when the user operates the touch panel or the operation key group, the display operation unit 160 outputs various operation signals corresponding to the operation content to the tandem system management unit 190.

  As shown in FIG. 2, the second image forming unit 200 includes a second paper feed tray 210, a second print processing unit 220, transport path switching units 230 and 231 and transport paths T6, T7, T8, and T9. , Including.

  The second paper feed tray 210 includes a plurality of trays, and accommodates the paper identified based on the amount of paper, the size, etc., in each tray for each type set by the user. The paper stored in the second paper feed tray 210 is transported from the transport path T6 to the transport path T7 by the transport rollers.

  The second print processing unit 220 forms a color or monochrome image by electrophotography on a sheet, and performs color or monochrome print processing by heating and fixing the formed image. The second print processing unit 220 includes a second image forming unit 221 configured with a photosensitive drum, a laser unit, and the like, and a second fixing unit 222 configured with a fixing roller and the like.

  As shown in FIG. 3, the second image forming unit 221 includes a toner image generating unit 2211, an intermediate transfer belt 2212, a registration roller 2213, a guide plate 2214, and a secondary transfer belt 2215. The

The toner image generation unit 2211 includes a C color toner image generation unit 2211a, an M color toner image generation unit 2211b, a Y color toner image generation unit 2211c, and a K color toner image generation unit 2211d. The toner image generation unit 2211 includes a charging device, an exposure device, a photosensitive drum, and the like for each of the C color toner image generation units 2211a to 2211d.
When the toner image generation unit 2211 generates a color toner image, the C color toner image generation unit 2211a to the K color toner image generation unit 2211d perform electrostatics including CMYK colors based on the input image data. A latent image is formed on each photosensitive drum by a charging device or an exposure device. Further, the toner image generation unit 2211 forms a color toner image on the respective photosensitive drums from the electrostatic latent images of CMYK colors using a developing device or the like.
On the other hand, when forming a monochrome toner image, the toner image generation unit 2211 forms a K-color electrostatic latent image on the photosensitive drum by the K-color toner image generation unit 2211d based on the input image data. A toner image is formed on the photosensitive drum from the electrostatic latent image by a developing device or the like.
The toner image generation unit 2211 applies a driving force from a motor (not shown) or the like, so that the toner image generation unit 2211 is in close contact with the intermediate transfer belt 2212 and is separated from the C color toner image generation units 2211a to 2211a. Switching can be performed for each generation unit 2211d. Of course, it is possible to provide a structure that can switch between a state of being in close contact with the toner image generation unit 2211 and a state of being separated from the intermediate transfer belt 2212.

The intermediate transfer belt 2212 is configured to be rotatable in the direction of the arrow (solid line) in FIG. 3, and the intermediate transfer belt 2212 is a toner image generation unit 2211 (C color toner image generation unit 2211a to K color toner image generation). The toner image formed by the toner image generation unit 2211 is intermediately transferred to the paper by rotating in close contact with the unit 2211d). The intermediate transfer belt 2212, together with the secondary transfer belt 2215, transfers a toner image onto a sheet, and carries the sheet toward the second fixing unit 222.
The guide plate 2214 guides the paper carried from the first image forming unit 100 and the paper fed from the second paper feed tray 210 to be conveyed toward the registration roller 2213 and the intermediate transfer belt 2212. The registration roller 2213 aligns the leading edge of the paper conveyed by the guide plate 2214. Then, the registration roller 2213 carries the sheet toward the intermediate transfer belt 2212 at a timing when the intermediate transfer belt 2212 transfers the toner image onto the sheet. The secondary transfer belt 2215 presses the intermediate transfer belt 2212 to transfer the toner image on the intermediate transfer belt 2212 to a sheet.

  The second fixing unit 222 includes a plurality of fixing rollers that rotate in the forward direction with respect to the sheet conveyance direction and a fixing belt that winds the fixing rollers. The second fixing unit 222 heats and presses the paper carried into the nip portion of the second fixing unit 222 to heat and fix the toner image on the paper.

The conveyance path switching unit 230 is either a sheet that is carried into the conveyance path switching unit 230 via the conveyance path T5 or a sheet that is carried into the conveyance path switching unit 230 via the conveyance path T6. The transport path is switched so that the sheet of paper is transported to the transport path T7.
The transport path switching unit 231 transports the paper carried into the transport path switching unit 231 via the transport path T7 to the transport path T9 with the front and back sides of the paper reversed via the transport path T8. Whether to transport to the transport path T9 without passing through the transport path T8 is switched.

  The post-processing unit 400 performs predetermined post-processing on the paper that is carried in via the transport path T9. Examples of post-processing performed by the post-processing unit 400 include sort processing, cutting processing, punching processing, and stapling processing. One or a plurality of the post-processing units 400 are arranged in series according to the processing content desired by the user. The paper that has been post-processed by the post-processing unit 400 is discharged via the paper discharge trays 411 and 412 provided in the post-processing unit 400.

  Next, the functional configuration of the image forming apparatus 1 will be described with reference to the block diagram shown in FIG.

  As shown in FIG. 4, the image forming apparatus 1 includes a paper feeding unit 300, a first image forming unit 100, a second image forming unit 200, and a post-processing unit 400. The units from the first image forming unit 100 to the post-processing unit 400 are connected so that data can be transmitted and received by serial communication or the like.

  The first image forming unit 100 includes an ADF control unit 141, a scanner control unit 151, a first print processing unit 120, a first paper transport unit 132 (reversing unit), a first paper feed tray control unit 111, A first control unit 170, a first state management unit 171, a paper feed unit control unit 172, a first image processing unit 180 (image rotation unit), and a tandem system management unit 190 (control unit) are included. Composed.

The ADF control unit 141 performs drive control of the ADF 140 when a document is placed on the ADF 140. The scanner control unit 151 performs reading control of a document image by the scanner 150. The first paper feed tray control unit 111 performs control to feed paper from one of the plurality of trays provided in the first paper feed tray 110.
The first paper transport unit 132 is configured to feed paper fed from the first paper feed tray 110 via the transport path switching unit 130 (paper passing through the transport path T2) or paper carried from the paper feed unit 300 (conveyance). Control is performed to transport any one of the sheets passing through the path T1 to the transport path T3. In addition, the first paper transport unit 132 passes the transported paper through the transport path switching unit 131 to the transport path switching unit 131 via the transport path T3 and the front and back of the paper through the transport path T4. Control is performed to switch between reversing and transporting to the transport path T5 or transporting to the transport path T5 without passing through the transport path T4.

  The first control unit 170 follows the instruction signal transmitted from the tandem system management unit 190, the ADF control unit 141, the scanner control unit 151, the first paper feed tray control unit 111, the first print processing unit 120, the first paper transport The drive of the unit 132, etc. is controlled.

  The first state management unit 171 manages (controls) the entire operation of the first image forming unit 100 based on an instruction from the tandem system management unit 190. Specifically, the first state management unit 171 transmits an instruction signal to the first image processing unit 180 to perform control for generating an image for printing.

  The paper feed unit control unit 172 transmits an instruction signal to the paper feed unit 300 and feeds paper from one of the plurality of trays provided in the paper feed unit 300 to the first image forming unit 100.

The first image processing unit 180 performs various image processing according to the instruction signal transmitted from the first state management unit 171 and generates an image for printing. For example, the first image processing unit 180 performs RIP processing or the like on a print job transmitted from a PC (Personal Computer) connected to the first image forming unit 100 via a LAN (Local Area Network) or the like. Generate an image for printing. Further, the first image processing unit 180 generates an image for printing based on the original image read by the scanner 150.
The image generated by the first image processing unit 180 is output to the first state management unit 171. Here, according to the instruction signal from the tandem system management unit 190, the first image processing unit 180 outputs the image to the first state management unit 171 in a state where the image is rotated by 180 degrees around an axis perpendicular to the paper surface. be able to.

The tandem system management unit 190 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). The tandem system management unit 190 reads various programs stored in the ROM and develops them in the RAM. Then, the tandem system management unit 190 controls the overall operation of the first image forming unit 100 by executing the developed various programs and outputting various instruction signals to the first state management unit 171. The tandem system management unit 190 also controls the operation of the second image forming unit 200 via the second state management unit 271 by outputting an instruction signal to the second state management unit 271 described later by serial communication. That is, the tandem system management unit 190 functions as a control unit.
Specifically, when the tandem system management unit 190 receives a print instruction (a print job transmitted from a PC or the like, or a print processing execution instruction from the user via the display operation unit 160), the tandem system management unit 190 responds to the print instruction. Based on this, it is determined which one of the first image forming unit 100 and the second image forming unit 200 is to execute the printing process on one side or the opposite side of the sheet.
In addition, the tandem system management unit 190 transmits a color mode and a monochrome mode to each of the first image forming unit 100 and the second image forming unit 200 via the first state management unit 171 and a second state management unit 271 described later. Switch between these modes. Here, the color mode is a mode for the first image forming unit 100 and the second image forming unit 200 to perform color printing processing on one side of a sheet. The monochrome mode is a mode for the first image forming unit 100 and the second image forming unit 200 to execute monochrome printing processing on one side of the paper.
That is, when the first image forming unit 100 is set to the color mode, the tandem system management unit 190 intermediates all of the C color toner image generation units 1211a to 1211d provided in the toner image generation unit 1211. The toner is driven in close contact with the transfer belt 1212 so that a color toner image can be generated. On the other hand, when the first image forming unit 100 is set to the monochrome mode, the tandem system management unit 190 includes the C color toner image generation unit 1211a to the K color toner image generation unit 1211d provided in the toner image generation unit 1211. Only the K-color toner image generation unit 1211d is driven in close contact with the intermediate transfer belt 1212 so that a monochrome toner image can be generated. In this case, the tandem system management unit 190 stops the C color toner image generation units 1211a to 1211c in a state of being separated from the intermediate transfer belt 1212, thereby causing the C color toner image generation units 1211a to 1211a. The lifetime of each component provided in the toner image generation unit 1211c can be improved. Here, when the tandem system management unit 190 sets the color or monochrome mode for the second image forming unit 200, the operation is the same as when the mode is set for the first image forming unit 100.
The first control unit 170 and the first state management unit 171 include a CPU, a RAM, and a ROM, and the functions of the tandem system management unit 190 are realized by the first control unit 170 and the first state management unit 171. Of course it is also good.

  The second image forming unit 200 includes a second paper feed tray control unit 211, a second print processing unit 220, a second paper transport unit 232 (reversing unit), a second control unit 270, and a second state management unit. 271, a post-processing unit control unit 272, and a second image processing unit 280 (image rotation unit).

The second paper feed tray control unit 211 performs control to feed paper from one of the plurality of trays provided in the second paper feed tray 210.
The second paper transport unit 232 is a paper fed from the second paper feed tray 210 (a paper passing through the transport path T6) or a paper carried in from the first image forming unit 100 via the transport path switching unit 230. Control is performed to convey any one of the sheets (the sheet passing through the conveyance path T5) to the conveyance path T7. Further, the second paper transport unit 232 transports the paper that has been carried into the transport path switching unit 231 via the transport path T7 via the transport path switching unit 231 to the transport path T9 via the transport path T8. Or a control for switching between transport to the transport path T9 without passing through the transport path T8.

  The second control unit 270 controls the driving of the second paper feed tray control unit 211, the second print processing unit 220, the second paper transport unit 232, and the like according to the instruction signal transmitted from the second state management unit 271. .

  The second state management unit 271 manages (controls) the entire operation of the second image forming unit 200 based on an instruction from the tandem system management unit 190. Specifically, the second state management unit 271 transmits an instruction signal to the second image processing unit 280, and controls generation of an image for printing.

  The post-processing unit control unit 272 transmits an instruction signal to the post-processing unit 400 to perform necessary post-processing on the paper that is carried out through the transport path T9.

  The second image processing unit 280 performs various image processing according to the instruction signal transmitted from the second state management unit 271 and generates an image for printing. The image generated by the second image processing unit 280 is formed on the paper by the second image forming unit 221. Here, according to the instruction signal from the tandem system management unit 190, the second image processing unit 280 can output the image to the second state management unit 271 in a state where the image is rotated by 180 degrees around an axis perpendicular to the paper surface. it can.

About duplex printing
Next, a procedure in which the tandem system management unit 190 executes a printing process (double-sided printing process) on both sides of a sheet to be printed (a printing sheet) according to a printing instruction will be described. In this case, the tandem system management unit 190 performs control so that the printing paper follows the path indicated by the arrow in FIG.
Specifically, as shown in FIG. 5, the tandem system management unit 190 performs the first paper feed tray 110 or the paper feed unit tray 310 via the first paper feed tray control unit 111 or the paper feed unit control unit 172. The printing paper is fed from one of the trays. Next, the tandem system management unit 190 carries the fed print paper into the transport path T3 via the transport path T1 or T2 via the first paper transport section 132. Next, the tandem system management unit 190 forms an image (color or monochrome toner image) generated by the first image processing unit 180 on the printing paper via the first image forming unit 121, and the first fixing unit 122 is formed. Then, the image is heat-fixed on the printing paper.

Next, the tandem system management unit 190 reverses the front and back of the print paper via the first paper transport unit 132 via the transport path T4 and then passes the print paper via the transport path T5 to the second. It is carried into the image forming unit 200. Next, the tandem system management unit 190 transports the printing paper to the transport path T7 via the second paper transport unit 232. Next, the tandem system management unit 190 forms an image (color or monochrome toner image) generated by the second image processing unit 280 via the second image forming unit 221 on the printing paper, and the second fixing unit 222 is formed. Then, the image is heat-fixed on the printing paper.
Then, the tandem system management unit 190 carries the printing paper into the post-processing unit 400 via the transport path T9 via the second paper transport unit 232, and performs predetermined post-processing in the post-processing unit 400. Eject paper. As will be described later, when the tandem system management unit 190 transports the print sheet from the transport path T7 to the transport path T9, the tandem system management unit 190 reverses the front and back of the print sheet via the transport path T8 and the transport path T8. There are cases where it is not allowed.

(Setting of pages on which the first image forming unit and the second image forming unit perform print processing)
Next, when the tandem system management unit 190 receives a print instruction and performs print processing on a plurality of print sheets according to the print instruction, the tandem system management unit 190 performs color print processing on one side of the paper and monochrome on the opposite side of the single side. A case where mixed print sheets that need to be printed are included will be described. In addition to mixed printing paper, double-sided color printing paper that requires color printing on both sides of the paper and double-sided monochrome printing that requires monochrome printing on both sides of the paper. Paper.
As a specific example, as shown in FIG. 6, the first printing paper performs color printing on the surface corresponding to the odd page (first page) and the surface corresponding to the even page (second page). This is a mixed printing paper to be subjected to monochrome printing processing, and the second printing paper performs monochrome printing processing on the surface corresponding to the odd page (page 3) and corresponds to the even page (page 4). The third printing paper performs monochrome printing on the surface corresponding to the odd page (5th page) and the even page (6th page). ) Is a double-sided monochrome printing paper on which monochrome printing processing is to be performed.

In this case, the tandem system management unit 190 sets the first image forming unit 100 to the monochrome mode and sets the second image forming unit 200 to the color mode when performing the printing process of the first printing paper (mixed printing paper). Set to mode. That is, in the tandem system management unit 190, the second image forming unit 200 performs the odd page (first page) printing process so that the first image forming unit 100 performs the even page (second page) printing process. Set as follows.
If the first image forming unit 100 is set to the color mode, the toner image generation unit 1211 drives all of the C color toner image generation units 1211a to 1211d and the intermediate transfer belt 1212. It is necessary to move it so that it moves closely. In particular, it is necessary to drive the respective photosensitive drums provided in the C color toner image generation unit 1211a to the K color toner image generation unit 1211d with a time difference. On the other hand, when the first image forming unit 100 is set to the monochrome mode, the toner image generating unit 1211 drives only the K-color toner image generating unit 1211d and moves it in close contact with the intermediate transfer belt 1212. Just do it.
Therefore, for the first image forming unit 100, the rise time from the stop state to the monochrome mode until the print processing is enabled is the rise time from the stop state to the color mode and the print processing is enabled. Shorter than This also applies to the second image forming unit 200.
Therefore, when the first printing sheet is a mixed printing sheet, the tandem system management unit 190 sets the monochrome mode with a short rise time in the first image forming unit 100 to perform the printing process for the first page. You can start quickly. Further, since the tandem system management unit 190 can set the color mode in the second image forming unit 200 by using the time until the printing process for the first page is completed, the printing process for the second page is also performed. You can get started quickly.

Next, the tandem system management unit 190 is set in each of the first image forming unit 100 and the second image forming unit 200 when performing the printing process of the second printing paper (mixed printing paper). Based on the mode, each unit determines which of the odd-numbered page (third page) or even-numbered page (fourth page) is to be printed.
Specifically, the tandem system management unit 190 sets odd-numbered pages (third page) that require monochrome printing processing to even-numbered pages (fourth page) that the first image forming unit 100 requires color printing processing. The second image forming unit 200 determines to perform the printing process. This is because the first image forming unit 100 is in the monochrome mode and the second image forming unit 200 is in the color mode at the time when the printing process for the second printing paper is performed. This is for setting so that the second printing paper can be printed without switching the monochrome or color mode set to “1”. In other words, the tandem system management unit 190 does not change the mode set for each unit, but only changes the surface of the printing paper on which each unit prints. As a result, the productivity (speed of the printing process) for the printing process can be increased.

Next, the tandem system management unit 190 is set in each of the first image forming unit 100 and the second image forming unit 200 when performing the printing process of the third printing sheet (double-sided monochrome printing sheet). Based on the selected mode, each unit determines which of the odd-numbered page (5th page) or even-numbered page (6th page) is to be printed.
In this case, the first image forming unit 100 is in the monochrome mode and the second image forming unit 200 is in the color mode when the third printing paper is printed, and each unit performs the monochrome printing process. Can do. Therefore, the tandem system management unit 190 may be configured to perform printing processing for either odd-numbered pages or even-numbered pages. As an example, FIG. 6 shows a case where the odd image (page 5) is determined to be printed by the first image forming unit 100 and the even page (page 6) is determined to be printed by the second image forming unit 200. Show.

  Here, since the second image forming unit 200 is in the color mode, there are cases where the tandem system management unit 190 performs the setting for switching the second image forming unit 200 to the monochrome mode and the setting for maintaining the color mode. Conceivable. In other words, the tandem system management unit 190 can improve the productivity for the printing process by maintaining the second image forming unit 200 in the color mode because the time required for switching the mode can be omitted. Switching to the monochrome mode can improve the resource life of the image forming apparatus 1 (that is, improve the life of each component provided in the toner image generating unit 2211). Therefore, the tandem system management unit 190 causes the user to pre-select which setting is to be performed in the above case.

Specifically, when the user presses the button 510 while the key operator menu screen 500 shown in FIG. 7 is displayed via the display operation unit 160, the tandem system management unit 190 is shown in FIG. A tandem operation setting screen 520 is displayed.
The user can select and determine the productivity priority from high, medium, and low via the display operation unit 160. Here, when the user sets the productivity priority to low, the tandem system management unit 190 sets the mode of each unit so that the resource life of the image forming apparatus 1 is improved as described above.

  On the other hand, when the productivity priority is set to high or medium, the tandem system management unit 190 performs monochrome according to the remaining number of print sheets according to the print instruction after the mode is set for each unit. Switch between switching to mode and maintaining color mode. That is, for example, the tandem system management unit 190 has N sheets of printing paper according to the print instruction, and when the mode is set for each unit, the printing process of K (K <N) sheets is completed. If it is, it is determined whether or not the remaining number obtained by subtracting K from N exceeds a predetermined threshold value. If the tandem system management unit 190 determines that the threshold value is exceeded, the remaining number of print sheets is sufficient (in consideration of the resource life of the image forming apparatus 1), and the second image forming unit 200 is set to monochrome. Set when switching to mode. On the other hand, when the tandem system management unit 190 determines that the threshold value is not exceeded, the remaining number of print sheets is small (prioritizing the productivity of print processing), so the second image forming unit 200 is set to the color mode. Make settings for maintaining. Note that the tandem system management unit 190 sets the threshold value to a larger value when the productivity priority is high than when the productivity priority is medium.

(About image rotation and printing paper reversal)
Next, based on the mode set for each of the first image forming unit 100 and the second image forming unit 200, the tandem system management unit 190 prints either odd or even pages. An image rotation process and a print sheet reversal process performed when it is determined whether to perform the process will be described.
Here, as shown in FIG. 9I, the tandem system management unit 190 forms an image of “1” on the surface corresponding to the odd pages of the printing paper and “2” on the surface corresponding to the even pages. It is assumed that printing processing is performed. Then, the tandem system management unit 190 has the surface corresponding to the even page shown in FIG. 9I on the upper side when outputting (paper discharge) and the upper side of the surface corresponding to the even page. It is assumed that control is performed so as to output from the direction of the arrow shown. In the following description, P1 to P4 shown in FIG. 9 (i) are points corresponding to P1 to P4 shown in FIG.

First, a case will be described in which the tandem system management unit 190 is set so that the first image forming unit 100 performs a printing process for odd pages and the second image forming unit 200 performs an even page printing process.
In this case, the tandem system management unit 190 forms an image “1” on the surface corresponding to the odd page via the first image forming unit 121. Then, an image “1” is formed on the printing paper at a point in front of the conveyance path T4 indicated by P1 in FIG. 9 (ii) in the direction opposite to the conveyance direction of the printing paper. Next, as indicated by P2 in FIG. 9 (ii), the tandem system management unit 190 inverts the front and back of the printing paper via the transport path T4 so that the surface corresponding to the even page is the upper surface.
Next, the tandem system management unit 190 forms an image “2” on the surface corresponding to the even page via the second image forming unit 221. Then, an image “2” is formed on the printing paper at the point in front of the conveyance path T8 indicated by P3 in FIG. 9 (ii) in the same direction as the conveyance direction of the printing paper. Then, the printing paper is in a state where the images of “1” and “2” are in the same direction as shown in FIG. 9I and the surface corresponding to the even page is the upper surface at the point of P3. Therefore, as indicated by P4 in FIG. 9 (ii), the output is made without passing through the transport path T8.

Next, a case will be described in which the tandem system management unit 190 is set so that the first image forming unit 100 prints even pages and the second image forming unit 200 prints odd pages.
In this case, the tandem system management unit 190 causes the first image processing unit 180 to form an image “2” in a direction rotated by 180 degrees as indicated by P1 in FIG. 9 (ii). The image “2” is rotated. Then, the tandem system management unit 190 forms an image “2” that is rotated on the surface corresponding to the even page via the first image forming unit 121. Then, as indicated by P1 in FIG. 9 (iii), an image “2” is formed on the printing paper in the same direction as the conveyance direction of the printing paper.
Next, as indicated by P2 in FIG. 9 (iii), the tandem system management unit 190 reverses the front and back of the printing paper via the conveyance path T4 so that the surface corresponding to the odd-numbered page is the upper surface.
Next, the tandem system management unit 190 causes the second image processing unit 280 to form the image “1” in a direction rotated by 180 degrees as indicated by P3 in FIG. 9 (ii). The image “1” is rotated. Then, the tandem system management unit 190 forms an image of “1” rotated on the surface corresponding to the odd page via the second image forming unit 221. Then, as indicated by P3 in FIG. 9 (iii), an image “1” is formed on the printing paper in the direction opposite to the conveyance direction of the printing paper.
Next, the tandem system management unit 190 reverses the front and back sides of the printing paper via the transport path T8 so that the surface corresponding to the even page is the upper surface. Then, as indicated by P4 in FIG. 9 (iii), the printing paper is such that the images of “1” and “2” have the same orientation as that shown in FIG. Output in the state of

(Print setting process)
Next, print setting processing executed by the image forming apparatus 1 according to the present invention will be described with reference to the flowcharts of FIGS. Note that the processes according to FIGS. 10 to 13 are executed for each print sheet corresponding to the print instruction.

  First, when receiving a print instruction, the tandem system management unit 190 determines whether or not it is necessary to perform double-sided printing on one of the plurality of print sheets according to the print instruction. (Step S1). If the tandem system management unit 190 determines that it is not necessary to perform double-sided printing processing in step S1 (step S1; No), the first image forming unit 100 or the second image forming unit 200 causes the printing paper to be printed. Is set for printing on one side (step S2), and the process proceeds to step S81.

  Next, the tandem system management unit 190 determines whether or not the printing paper determined in step S1 (hereinafter referred to as the printing paper) is the first printing paper among the plurality of printing papers ( Step S3).

  Next, when the tandem system management unit 190 determines in step S3 that it is the first printing sheet (step S3; Yes), it determines whether the printing sheet is a double-sided color printing sheet ( Step S4).

  Next, when the tandem system management unit 190 determines in step S4 that it is not a double-sided color printing sheet (step S4; No), it determines whether the printing sheet is a double-sided monochrome printing sheet (step S4). S5).

Next, when the tandem system management unit 190 determines in step S5 that it is a double-sided monochrome printing sheet (step S5; Yes), the unit (the first image forming unit 100 and the second image forming unit 200) is assigned to each unit. The monochrome mode is set (step S6), and the process proceeds to step S81.
On the other hand, if the tandem system management unit 190 determines in step S5 that it is not a double-sided monochrome printing sheet (that is, the printing sheet is a mixed printing sheet) (step S5; No), the first image forming unit. 100 is set to the monochrome mode, and the second image forming unit 200 is set to the color mode (step S7). Subsequently, as a result of setting the first image forming unit 100 to the monochrome mode in step S7, the tandem system management unit 190 performs the printing process for even pages of the printing paper (mixed printing paper). It is determined whether or not to perform (step S8). When the tandem system management unit 190 determines in step S8 that the even page printing process is to be performed (step S8; Yes), the process proceeds to step S81. On the other hand, if the tandem system management unit 190 determines in step S8 that the even page printing process is not performed (that is, the odd page printing process is performed) (step S8; No), FIG. The image rotation and print paper inversion processing shown are set (step S9), and the process proceeds to step S81.

  If the tandem system management unit 190 determines in step S4 that it is a double-sided color printing sheet (step S4; Yes), it sets a color mode for each unit (step S10), and performs the process of step S81. Migrate to

  Next, if the tandem system management unit 190 determines in step S3 that it is not the first printing sheet (step S3; No), it determines whether the printing sheet is a double-sided color printing sheet (step S3). S21).

  Next, when the tandem system management unit 190 determines in step S21 that it is not a double-sided color printing paper (step S21; No), it determines whether the printing paper is a double-sided monochrome printing paper (step S21). S22).

  Next, when the tandem system management unit 190 determines in step S22 that it is not a double-sided monochrome printing sheet (that is, the printing sheet is a mixed printing sheet) (step S22; No), the first image forming unit 100. Is determined to be in the color mode (step S23).

  If the tandem system management unit 190 determines that the color mode is set in step S23 (step S23; Yes), the first image forming unit 100 performs the printing process for the surface corresponding to the color page. (Step S24). Next, the tandem system management unit 190 determines whether or not the first image forming unit 100 performs the printing process of the surface corresponding to the even page (that is, whether or not the color page is the even page) according to the setting in step S24. ) Is determined (step S25). If the tandem system management unit 190 determines in step S25 that the even page printing process is to be performed (step S25; Yes), the process proceeds to step S27. On the other hand, if the tandem system management unit 190 determines in step S25 that the even page printing process is not performed (that is, the odd page printing process is performed) (step S25; No), FIG. The image rotation and print paper inversion processing shown are set (step S26), and the process proceeds to step S27.

Next, the tandem system management unit 190 determines whether or not the second image forming unit 200 is set to the monochrome mode (step S27). If the tandem system management unit 190 determines that the monochrome mode is set in step S27 (step S27; Yes), the process proceeds to step S32.
On the other hand, if the tandem system management unit 190 determines that the monochrome mode is not set in step S27 (step S27; No), the productivity priority is set to low for the user via the tandem operation setting screen 520. It is determined whether or not it has been done (step S28).
Next, when it is determined that the tandem system management unit 190 is not set to low (that is, set to high or medium) in step S28 (step S28; No), the remaining number of print sheets is larger than the threshold value. Whether or not (step S29).
Next, when it is determined that the tandem system management unit 190 is set to low in step S28 (step S28; Yes), or when it is determined that the threshold value is larger than the threshold value in step S29 (step S29; Yes), the second image. The forming unit 200 is switched to the monochrome mode (step S30). On the other hand, if the tandem system management unit 190 determines that it is smaller than the threshold value in step S29 (step S29; No), the second image forming unit 200 is maintained in the color mode (step S31). Then, the tandem system management unit 190 sets the second image forming unit 200 to perform the printing process of the surface corresponding to the monochrome page (step S32), and proceeds to the process of step S81.

Next, when the tandem system management unit 190 determines in step S23 that the color mode is not set (that is, the monochrome mode is set) (step S23; No), the first image forming unit 100 is monochrome. It is set to perform the printing process of the surface corresponding to the page (step S33).
Next, the tandem system management unit 190 determines whether or not the second image forming unit 200 is set to the color mode (step S34). If the tandem system management unit 190 determines that the color mode is set in step S34 (step S34; Yes), the process proceeds to step S36. On the other hand, when the tandem system management unit 190 determines in step S34 that the color mode is not set (step S34; No), the second image forming unit 200 is switched to the color mode (step S35).
Then, the tandem system management unit 190 sets the second image forming unit 200 to perform the printing process of the surface corresponding to the color page (step S36).

  Next, the tandem system management unit 190 determines whether or not the second image forming unit 200 performs the printing process corresponding to the odd-numbered pages (that is, whether the color pages are odd-numbered pages) according to the setting in step S36. ) Is determined (step S37). If the tandem system management unit 190 determines in step S37 that the odd page printing process is not performed (that is, the even page printing process is performed) (step S37; No), the process proceeds to step S81. . On the other hand, if the tandem system management unit 190 determines that the odd-numbered page printing process is to be performed in step S37 (step S37; Yes), the image rotation and printing paper reversal processing illustrated in FIG. 9 (iii) is performed. Settings are made (step S38), and the process proceeds to step S81.

Next, when the tandem system management unit 190 determines in step S22 that it is a double-sided monochrome printing sheet (step S22; Yes), it determines whether or not the first image forming unit 100 is set to the monochrome mode. (Step S41). If the tandem system management unit 190 determines that the monochrome mode is set in step S41 (step S41; Yes), the process proceeds to step S46.
On the other hand, if the tandem system management unit 190 determines in step S41 that the monochrome mode has not been set (that is, the color mode has been set) (step S41; No), the tandem system management unit 190 passes the tandem operation setting screen 520. It is then determined whether or not the productivity priority is set to low for the user (step S42).
Next, when the tandem system management unit 190 determines in step S42 that the setting is not low (No in step S42), the tandem system management unit 190 determines whether the remaining number of print sheets is larger than the threshold (step S43).
Next, when the tandem system management unit 190 determines that the value is set low in step S42 (step S42; Yes), or when it is determined that the value is larger than the threshold value in step S43 (step S43; Yes), the first image The forming unit 100 is switched to the monochrome mode (step S44). On the other hand, if the tandem system management unit 190 determines that the threshold value is smaller than the threshold value in step S43 (step S43; No), the tandem system management unit 190 maintains the first image forming unit 100 in the color mode (step S45). Then, the tandem system management unit 190 sets the first image forming unit 100 to perform a printing process on a surface corresponding to a monochrome page (either odd page or even page) (step S46).

Next, the tandem system management unit 190 determines whether or not the second image forming unit 200 is set to the monochrome mode (step S47). If the tandem system management unit 190 determines that the monochrome mode is set in step S47 (step S47; Yes), the process proceeds to step S52.
On the other hand, if the tandem system management unit 190 determines that the monochrome mode is not set in step S47 (step S47; No), the productivity priority is set to low for the user via the tandem operation setting screen 520. It is determined whether or not it has been done (step S48).
Next, when the tandem system management unit 190 determines in step S48 that the setting is not low (step S48; No), the tandem system management unit 190 determines whether the remaining number of print sheets is larger than the threshold (step S49).
Next, when it is determined that the tandem system management unit 190 is set to be low in step S48 (step S48; Yes), or when it is determined that the threshold is larger than the threshold value in step S49 (step S49; Yes), the second image. The forming unit 200 is switched to the monochrome mode (step S50). On the other hand, if the tandem system management unit 190 determines in step S49 that the threshold is smaller than the threshold (step S49; No), the tandem system management unit 190 maintains the second image forming unit 200 in the color mode (step S51). Then, the tandem system management unit 190 sets the second image forming unit 200 to perform a printing process on the surface corresponding to the monochrome page (the surface opposite to the surface set in Step S46) (Step S52). The process proceeds to S81.

Next, if the tandem system management unit 190 determines in step S21 that it is a double-sided color printing sheet (step S21; Yes), it determines whether or not the first image forming unit 100 is set to the color mode. (Step S61). If the tandem system management unit 190 determines that the color mode is set in step S61 (step S61; Yes), the process proceeds to step S63. On the other hand, if the tandem system management unit 190 determines in step S61 that the color mode is not set (step S61; No), the tandem system management unit 190 switches the first image forming unit 100 to the color mode (step S62).
Then, the tandem system management unit 190 performs setting so that the first image forming unit 100 performs a printing process on a surface corresponding to a color page (either odd page or even page) (step S63).

Next, the tandem system management unit 190 determines whether or not the second image forming unit 200 is set to the color mode (step S64). If the tandem system management unit 190 determines that the color mode is set in step S64 (step S64; Yes), the process proceeds to step S66. On the other hand, if the tandem system management unit 190 determines in step S64 that the color mode is not set (step S64; No), the second image forming unit 200 is switched to the color mode (step S65).
Then, the tandem system management unit 190 sets the second image forming unit 200 to perform printing processing on the surface corresponding to the color page (the surface opposite to the surface set in step S63) (step S66). The process proceeds to S81.

  Next, the tandem system management unit 190 executes the printing process of the printing paper based on the setting of each unit (step S81), and whether or not all the printing processes of the plurality of printing papers according to the printing instruction are completed. Is determined (step S82). If the tandem system management unit 190 determines that the process is not completed in step S82 (step S82; No), the process after step S1 is repeated. On the other hand, if the tandem system management unit 190 determines that the process is completed in step S82 (step S82; Yes), the process is terminated.

  Note that even when the tandem system management unit 190 determines that the even-numbered page printing process is to be performed in steps S8, S25, and S37 (step S8; Yes, step S25; Yes, step S37; No), duplex printing is performed. In order to perform the processing, setting for reversing the front and back of the printing paper through the transport path T4 is performed.

As described above, according to the image forming apparatus 1 according to the present embodiment, the tandem system management unit 190 includes each unit of the first image forming unit 100 and the second image forming unit 200 when mixed printing paper is included in the printing paper. On the basis of the mode set in (1), each unit determines which side of the printing paper is to be printed, which is an even page or an odd page.
That is, in the image forming apparatus 1, it is not fixed on which side each unit performs the printing process. Therefore, for example, the image forming apparatus 1 is set in a state where the first image forming unit 100 is set to perform odd-numbered page printing processing in the monochrome mode and the second image forming unit 200 is configured to perform even-numbered page printing processing in the color mode. Even when performing color printing on odd-numbered pages and mixed printing paper that should be printed on monochrome even-numbered pages, each unit can operate without switching the mode set for each unit. By simply changing the surface on which the printing process is performed, the mixed printing paper can be printed. As a result, since it is not necessary to sequentially switch the mode set for each unit for each printing paper, the printing paper productivity in the printing process is good because the time required for the switching is omitted.
Therefore, the present invention is an image forming apparatus that, when performing printing processing of a plurality of printing papers including mixed printing papers, does not reduce the printing paper productivity in the printing processing as much as possible.

In addition, when the first printing paper is a mixed printing paper, the tandem system management unit 190 can perform printing processing between the color mode and the monochrome mode when performing printing processing on the first printing paper. A monochrome mode with a short rise time until the time is set in the first image forming unit 100.
Therefore, the tandem system management unit 190 can quickly start the printing process for the first printing sheet.

Further, the tandem system management unit 190 applies either the color mode or the monochrome mode to the first image forming unit 100 or the second image forming unit 200 according to the productivity priority selected through the display operation unit 160. Set the mode.
Therefore, the tandem system management unit 190 sets the appropriate mode to the first image forming unit 100 or the second mode depending on whether the user prioritizes the productivity of printing paper or the improvement of the resource life of the image forming apparatus 1. It can be set in the image forming unit 200.

  Also, the tandem system management unit 190 rotates the image and prints the paper so that all the printing papers are output with the same surface of the printing paper facing the upper surface and the image is output from the same orientation. The inversion process can be performed as necessary.

The description in the above embodiment is an example of a suitable image forming apparatus according to the present invention, and the present invention is not limited to this.
Further, the detailed configuration and detailed operation of each part constituting the image forming apparatus in the above embodiment can be changed as appropriate without departing from the spirit of the present invention.

Specifically, for example, in the above embodiment, when the first printing paper is a mixed printing paper, the tandem system management unit 190 performs a monochrome mode when performing printing processing on the first printing paper. Is set in the first image forming unit 100. However, of course, the color mode may be set to the first image forming unit 100 when the color mode and the monochrome mode have a shorter rise time until the printing process is possible.
Further, in the image forming apparatus 1 of the present invention, the paper feeding unit 300, the first image forming unit 100, the second image forming unit 200, and the post-processing unit 400 are separately configured and connected. Even if it is a structure, they may be comprised integrally.

1 Image forming apparatus 100 First image forming unit (previous image forming unit)
120 First print processing unit 121 First image forming unit 131 Transport path switching unit 132 First paper transport unit (reversing unit)
160 Display operation unit (selection unit)
180 First image processing unit (image rotating unit)
190 Tandem system management unit (control unit)
200 Second image forming unit (following image forming unit)
220 Second print processing unit 221 Second image forming unit 230 Transport path switching unit 232 Second paper transport unit (reversing unit)
280 Second image processing unit (image rotating unit)
300 Paper feed unit 400 Post-processing unit

Claims (5)

An image forming apparatus capable of performing print processing on both sides of the paper by connecting an image forming unit capable of print processing on one side of the paper to a front stage and a rear stage,
The image forming unit can be set by switching between a color mode for performing color printing on one side of the paper and a monochrome mode for performing monochrome printing on one side of the paper;
When performing print processing on a plurality of print sheets according to a print instruction, mixed print sheets to be subjected to color print processing on one side of the paper and monochrome print processing on the opposite side of the one side are the plurality of print sheets. When included in the printing paper, according to the mode set in the image forming unit, a control unit that determines whether each of the image forming units performs printing processing on one side or the opposite side of the printing paper. An image forming apparatus comprising the image forming apparatus. The image forming apparatus according to claim 1,
When the first printing paper among the plurality of printing papers is the mixed printing paper, the control unit performs the color mode and the monochrome mode when performing printing processing on the first printing paper. An image forming apparatus in which a mode having a shorter rise time until printing processing is possible is set in the preceding image forming unit. The image forming apparatus according to claim 1,
A selection unit that selects which of the productivity of the printing paper in the printing process and the lifetime of each component included in the image forming apparatus is prioritized;
The image forming apparatus, wherein the control unit sets one of the color mode and the monochrome mode in the image forming unit in accordance with a selection result by the selection unit. The image forming apparatus according to any one of claims 1 to 3,
The image forming unit has a reversing unit for reversing the front and back of the paper after performing a printing process on one side of the paper,
The control unit reverses the front and back sides of the printing paper by the reversing unit so that the front and back directions of all the printing papers coincide when outputting the plurality of printing papers. apparatus. The image forming apparatus according to claim 4,
The image forming unit includes an image rotating unit that rotates an image formed on the paper,
The control unit rotates the image formed on the printing paper by the image rotating unit so that the orientations of the images of all the printing papers coincide when outputting the plurality of printing papers. Image forming apparatus.

Images