JP6958043B2 - Image forming device, image forming method and program - Google Patents

Description

The present invention relates to an image forming apparatus, an image forming method and a program.

Conventionally, an image forming apparatus capable of handling special colors such as clear and white in addition to normal colors such as cyan, magenta, yellow, and black has been known.
For example, in Patent Document 1, five photoconductor drums are arranged so as to face the intermediate transfer belt, and the four photoconductor drums form toner images of normal colors of black, yellow, magenta, and cyan, respectively. Disclosed is an image forming apparatus including an image forming portion in which a toner image is formed by a special color toner such as a transparent toner or a white toner in another photoconductor drum. In this image forming section, the toner image of the special color toner and the toner image of the normal color are transferred (primary transfer) on the intermediate transfer belt, and the toner image supported on the intermediate transfer belt is the intermediate transfer belt and the second. It is transferred (secondary transfer) on the paper at a position facing the next transfer member.

Japanese Unexamined Patent Publication No. 2016-90883

By the way, as a method of using a spot color, for example, after forming an image on paper in normal color, clear is superimposed on the entire paper as a coating, or after forming a solid white image as a base on the entire paper, in normal color. There is a request to form an image.
In this way, when forming an image on the same surface of the paper, in the device of Patent Document 1, it is necessary to set the paper on which the first image is formed again in the device, which is troublesome. Met.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus, an image forming method, and a program capable of reducing the time and effort required for forming an image on the same surface of paper. And.

In order to solve the above problems, the invention according to claim 1 is used in an image forming apparatus.
An image forming part that forms an image on paper,
An image forming path for transporting the paper to the image forming section, and an image forming path.
It branches from the image forming path downstream of the image forming section in the paper conveying direction, and joins the image forming path so that the image forming surface of the paper becomes the same surface upstream of the image forming section in the paper conveying direction. A circulation route that circulates paper and
A control unit that circulates the paper on which an image is formed by the image forming unit by the circulation path and executes an overwriting process for forming an image on the image forming surface by the image forming unit.
An inversion path that branches off from the circulation path and joins the image forming path so that the image forming surface of the paper is the back surface of the same surface upstream of the image forming section and circulates the paper.
Equipped with a,
It said image forming path and confluence of the circulation path, characterized by the paper conveying direction upstream der Rukoto the merging point between the reverse path and the image forming path.

Further, the invention according to claim 2 is the image forming apparatus according to claim 1.
The image forming unit is characterized in that an image of a normal color including yellow, magenta, cyan, and black and an image of a special color other than the normal color can be formed on paper.

Further, the invention according to claim 3 is the image forming apparatus according to claim 2.
When the control unit executes the overwriting process twice or more on one surface of the paper, the control unit forms a spot color image at the time of forming the first image or at the time of forming the last image, and at the time of forming other images, the normal color is formed. It is characterized by forming an image.

Further, the invention according to claim 4 is the image forming apparatus according to any one of claims 1 to 3.
The control unit is characterized in that the overwriting process is executed when the overwriting mode for forming an image on the same surface of the paper a plurality of times is selected.

Further, the invention according to claim 5 is
An image forming section that forms an image on paper, an image forming path that conveys the paper to the image forming section, and an image forming path that branches downstream from the image forming section in the paper conveying direction, and is more than the image forming section. The circulation path that joins the image forming path and circulates the paper so that the image forming surface of the paper becomes the same surface upstream in the paper conveying direction, and the image forming surface of the paper upstream of the image forming portion in the paper conveying direction. An inversion path that joins the image forming path and circulates the paper so as to be the back surface of the same surface and a control unit are provided , and the confluence point between the image forming path and the circulation path is the image forming path. an image forming method in an image forming apparatus Ru paper conveying direction upstream der of the merging point of the reverse path,
The control unit includes a step of circulating the paper on which an image is formed by the image forming unit by the circulation path and executing an overwriting process of forming an image on the image forming surface by the image forming unit. It is a feature.

Further, the invention according to claim 6 is
An image forming section that forms an image on paper, an image forming path that conveys the paper to the image forming section, and an image forming path that branches downstream from the image forming section in the paper conveying direction, and is more than the image forming section. The circulation path that joins the image forming path and circulates the paper so that the image forming surface of the paper becomes the same surface upstream in the paper conveying direction, and the image forming surface of the paper upstream of the image forming portion in the paper conveying direction. An inversion path that joins the image formation path and circulates the paper so as to be the back surface of the same surface is provided , and the confluence point between the image formation path and the circulation path is the image formation path and the inversion path. the computer image forming apparatus Ru paper conveying direction upstream der of the merging point with,
This is a program for circulating the paper on which an image is formed by the image forming unit by the circulation path and functioning as a control unit for executing an overwriting process of forming an image on the image forming surface by the image forming unit. ..

According to the present invention, it is possible to reduce the time and effort required to form an image by superimposing it on paper.

It is a block diagram which shows typically the image forming apparatus which concerns on this embodiment. It is a block diagram which shows schematic structure of the control system of the image forming apparatus of FIG. It is a flowchart which shows the image formation process which is executed in this embodiment.

Hereinafter, the present embodiment will be described in detail with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.

[Structure of image forming apparatus 100]
First, the configuration of the image forming apparatus 100 in the present embodiment will be described.
FIG. 1 is a configuration diagram schematically showing an image forming apparatus 100 according to the present embodiment. The image forming apparatus 100 is an electrophotographic image forming apparatus 100 such as a copying machine, and forms a full-color image by arranging a plurality of photoconductors in a vertical direction facing a single intermediate transfer belt. This is a so-called tandem type color image forming apparatus.

The image forming apparatus 100 is mainly composed of a document reading apparatus SC, an image forming unit 10, a paper conveying unit 20, and a control unit 11, and these are housed in one housing.

The document reading device SC scans and exposes an image of a document by the optical system of the scanning exposure device, reads the reflected light by a line image sensor, and obtains an image signal. This image signal is input to the control unit 11 as image data after being subjected to processing such as A / D conversion, shading correction, and compression. The image data input to the control unit 11 is not limited to the image data read by the document reading device SC, and is received from, for example, a personal computer or another image forming device connected to the image forming device 100 by the communication unit 13. It may be the one that has been used.

The image forming unit 10 includes four sets of normal color image forming units 10Y, 10M, 10C, 10K, one set of special color image forming units 10W, an intermediate transfer belt 6, a secondary transfer roller 8, a fixing device 9, and the like. It is composed of.
The image forming units 10Y, 10M, 10C, and 10K are an image forming unit 10Y that forms an image of yellow (Y), an image forming unit 10M that forms an image of magenta (M), and an image that forms an image of cyan (C). It is composed of a forming unit 10C and an image forming unit 10K that forms a black (K) image.
Further, the image forming unit 10W is composed of an image forming unit 10W that forms a white (W) image.

The image forming unit 10Y includes a photoconductor drum 1Y, a charging unit 2Y arranged around the photoconductor drum 1Y, an optical writing unit 3Y, a developing device 4Y, and a drum cleaner 5Y. Similarly, the image forming units 10M, 10C, 10K, 10W include the photoconductor drums 1M, 1C, 1K, 1W and the charging units 2M, 2C, 2K, 2W, and the optical writing units 3M, 3C, which are arranged around the photofinishing drums 1M, 1C, 1K, 1W. It is composed of 3K, 3W, developing devices 4M, 4C, 4K, 4W and drum cleaners 5M, 5C, 5K, 5W.

The surface of the photoconductor drums 1Y to 1W is uniformly charged by the charging portions 2Y to 2W, and a latent image is formed on the photoconductor drums 1Y to 1W by scanning exposure by the optical writing units 3Y to 3W. Will be done. Further, the developing devices 4Y to 4W visualize the latent image on the photoconductor drums 1Y to 1W by developing with toner. As a result, a toner image of a predetermined color corresponding to any of yellow, magenta, cyan, black, and white is formed on the photoconductor drums 1Y to 1W. The toner image formed on the photoconductor drums 1Y to 1W is sequentially transferred to a predetermined position on the rotating intermediate transfer belt 6 by the primary transfer rollers 7Y, 7M, 7C, 7K, 7W.

The toner image composed of each color transferred on the intermediate transfer belt 6 is transferred by the secondary transfer roller 8 to the paper P transferred at a predetermined timing by the paper transport unit 20 described later. The secondary transfer roller 8 is a pressure contact member that forms a nip portion (hereinafter referred to as “transfer nip portion”) by being arranged in pressure contact with the intermediate transfer belt 6.

The fixing device 9 is a device that performs a fixing process on the paper P on which the toner image is transferred, that is, the paper P sent out from the transfer nip portion, and is, for example, a pair of fixing members (for example, a pair of rollers) and the fixing. It is composed of a heater that heats one or both of the members. In the process of transporting the paper P, the fixing device 9 fixes the toner image on the paper P through the action of the pressure of the pair of fixing members and the heat of the fixing members.

The paper transport unit 20 transports the paper P according to the transport path of the paper P.
The paper transport unit 20 circulates an image forming path R1 for transporting the paper P to the image forming unit 10, a switching gate G, a paper ejection path R2 for discharging the paper P after image formation to the outside, and a paper P after image formation. A circulation path R3 and an ADU inversion path R4 for forming an image on both sides of the paper P are provided.

In each transport path, a plurality of transport means for transporting the paper P are provided. Each of the conveying means is composed of a pair of pressure-welded rollers, and the paper P is conveyed by rotationally driving at least one of the rollers through a drive mechanism mainly composed of an electric motor.
Further, the pair of rollers constituting the individual transport means are configured so that the state between the rollers can be switched between the pressure contact state and the separated state.
In addition to being composed of a pair of rollers, the transporting means can be widely adopted in a configuration composed of a pair of rotating members, such as a combination of belts and a combination of belts and rollers.

The image forming path R1 is a path for conveying the paper P from the paper feed tray to the switching gate G.
The paper P is housed in a paper feed tray 21 located at the lower part of the image forming apparatus 100, and the paper P housed in the paper feed tray 21 is taken in by the paper feeding unit 22 and enters the image forming path R1. Be sent out.
Alternatively, the paper P is housed in a paper feed tray of a paper feed device (not shown) connected to the image forming device 100, and the paper P held by the paper feeding device forms an image from the paper feeding device. It is supplied to the device 100 and sent out to the image forming path R1.
Further, the paper P may be placed on a manual feed tray provided in the image forming apparatus 100 and sent out to the image forming path R1.

An image forming portion 10 is provided on the image forming path R1. Further, the image forming path R1 is provided with an intermediate transport roller 23, a loop roller 24, and a resist roller 25 as transport means from the upstream side to the downstream side in the paper transport direction.

The paper P is sequentially conveyed by the intermediate transfer roller 23 and the loop roller 24, and advances along the image forming path R1. When the tip of the paper P approaches the resist roller 25, the paper P conveyed by the loop roller 24 or the like is abutted against the resist roller 25 in the stopped rotation state, and the loop roller 24 continues to rotate for a predetermined time. As a result, a loop is formed on the paper P. By the action of this loop formation, the bending of the tip of the paper P is corrected (skew correction).
Next, when the resist roller 25 starts rotating at a predetermined timing so as to synchronize with the toner image carried by the intermediate transfer belt 6, the intermediate transfer roller 23 and the loop roller 24 are switched from the pressure contact state to the separated state. The paper P is conveyed to the transfer nip portion of the image forming unit 10 only by the resist roller 25, and then transferred to the fixing device 9 by the secondary transfer roller 8. The paper P that has been subjected to the fixing process in the fixing device 9 is conveyed to the switching gate G.

The switching gate G is provided on the downstream side of the fixing device 9 in the paper transport direction, and switches the path for transporting the paper P transported from the image forming path R1. Specifically, the switching gate G guides the paper P downward when the paper P that has passed through the fixing device 9 is conveyed to the circulation path R3 or the ADU reversal path R4. Further, the switching gate G causes the paper P to go straight when the paper P is conveyed to the paper ejection path R2.
The switching gate G is normally in a state in which the paper P travels straight (sends to the paper ejection path R2). Then, when the paper P is conveyed downward (sent to the paper ejection path R2 or the circulation path R3), it is driven by a drive unit (not shown), and after the paper P is conveyed downward, it returns to the original state.

The paper discharge path R2 is a transport path for discharging the paper P, which has been fixed by the fixing device 9, to the paper discharge tray 26 attached to the outer side surface of the housing.

The circulation path R3 is a transport path for returning the paper P, which has been fixed by the fixing device 9, to the image forming path R1 again without changing the image forming surface (that is, without exchanging the front and back sides). Is.
The circulation path R3 branches from the image forming section 10 of the image forming path R1 downstream in the paper transport direction (position of the switching gate G), and is arranged so as to reach a confluence 51 provided in the middle of the image forming path R1. ing.
The circulation path R3 is provided with a reversing roller 27 and an intermediate transport roller 28 as transport means from the upstream side to the downstream side in the transport direction of the paper P. The intermediate transport rollers 28 are arranged so as to have an interval shorter than the length of the minimum paper P to pass in the paper transport direction.
The paper P supplied to the circulation path R3 is conveyed by the intermediate transfer roller 28 and reaches the confluence point 51. The paper P that has reached the confluence point 51 will be sent out to the image forming path R1 again.

The ADU reversing path R4 is a transport path for reversing the front and back of the paper P that has been fixed by the fixing device 9 and returning it to the image forming path R1, and is in the middle of the circulation path R3 (paper of the reversing roller 27). It branches from the upstream position in the transport direction) and is arranged so as to reach the confluence point 52 provided in the middle of the image forming path R1.
For example, when an image is formed on the back surface of the paper P, the paper P supplied to the circulation path R3 is reversed by the reversing roller 27 being inverted at the timing when the reversing roller 27 sandwiches the rear end of the paper P. It is fed, transported from the trailing end to the ADU inversion path R4, and reaches the confluence point 52 of the image forming path R1. The paper P that has reached the confluence point 52 will be sent out to the image forming path R1 again.

The image forming path R1, the circulation path R3, and the ADU inversion path R4 may be integrally configured so that they can be pulled out from the housing of the image forming apparatus 100.
At this time, the pair of rollers constituting the intermediate transfer roller 28 may be divided and pulled out only by the upper roller, or the upper and lower rollers may be pulled out together. In particular, if the upper and lower rollers are both pulled out, the jam treatment becomes easy, and it is possible to prevent the paper P from being inadvertently cut by the jam treatment.

FIG. 2 is a block diagram schematically showing a configuration of a control system of the image forming apparatus 100 according to the present embodiment.
As shown in FIG. 2, the control unit 11 is connected to a storage unit 12, a communication unit 13, an operation unit 14, a document reading device SC, an image forming unit 10, and a paper conveying unit 20.

The control unit 11 is composed of a CPU (Central Processing Unit), a RAM (Random Access Memory), and the like. The CPU of the control unit 11 reads out the system program and various processing programs stored in the storage unit 12 and expands them in the RAM, and centrally controls the operation of each unit of the image forming apparatus 100 according to the expanded program.
For example, when the operation unit 14 inputs a job execution command, the control unit 11 executes the job and causes the paper P to form a toner image based on the image data input by the document reading device SC and the communication unit 13. Take control.
Further, in the present embodiment, the control unit 11 circulates the paper P on which the image is formed by the image forming unit 10 by the circulation path R3, and the image forming unit 10 forms an image on the image forming surface. It is possible to execute the process.

The storage unit 12 is composed of a non-volatile semiconductor memory, an HDD (Hard Disk Drive), or the like, and stores various programs executed by the control unit 11 as well as parameters and data required by each unit.

The communication unit 13 is provided with various interfaces such as NIC (Network Interface Card), MODEM (Modulator-DEModulator), and USB (Universal Serial Bus), and connects to an external device.

The operation unit 14 outputs various information set by the user to the control unit 11. As the operation unit 14, for example, a touch panel capable of performing an input operation according to the information displayed on the display can be used. Through the operation unit 14, the user sets image formation conditions, that is, the type of paper P (for example, basis weight, size, paper quality, etc.), paper feed tray to be used, image density, magnification, image formation mode, and the like. be able to. In addition, the user can input job execution commands and operation instructions in various modes through the operation unit 14. Further, the control unit 11 can display various messages to the user via the operation unit 14 by controlling the operation unit 14.

[Operation of image forming apparatus 100]
Next, the operation of the image forming apparatus 100 in this embodiment will be described.
FIG. 3 is a flowchart showing an image forming process executed by the image forming apparatus 100. The process shown in this flowchart is executed in collaboration with the program stored in the control unit 11 and the storage unit 12 in response to a job execution command from the user.

First, the control unit 11 acquires job information transmitted from an external device via the communication unit 13 (step S1).
The job information includes various information related to the image forming process, for example, mode information, image data of the image to be formed, and the like.
As the mode information, for example, any one of a normal mode, a double-sided mode, and an overwriting mode is set. The normal mode is a mode in which an image is formed once on one side of the paper P. Further, the double-sided mode is a mode in which an image is formed on both sides of the paper P. Further, the overwriting mode is a mode in which an image is formed a plurality of times on one surface of the paper P.
The image data includes one or a plurality of image data according to the image formation mode, and information such as which side of the paper P is formed on the front or back side and the number of times the image data is formed is added.

Next, the control unit 11 executes the highest priority image formation among the unprocessed image formations by the image forming unit 10 (step S2).
For example, in the normal mode, the control unit 11 forms a normal color image on one side (front surface) of the paper P.
Further, for example, in the overwriting mode, the control unit 11 executes this when the first image formation is unprocessed, the first image formation is completed, and the second image formation is unprocessed. In the case of, the second image formation is executed. Specifically, for example, a solid white image is formed on one surface (front surface) of the paper P in the first image formation, and a normal color image is formed on the same surface (front surface) of the paper P in the second image formation. do.
Further, for example, in the double-sided mode, the control unit 11 executes this when the image formation on the front surface is not processed, and when the image formation on the front surface is completed and the image formation on the back surface is not processed, the control unit 11 executes this. Perform backside image formation. Specifically, for example, the control unit 11 forms a normal color image on the front surface of the paper P in the first image formation, and forms a normal color image on the back surface of the paper P in the second image formation.

Next, the control unit 11 determines whether or not the overwriting mode or the double-sided mode is set (step S3), and if the setting is not made (normal mode), this process is performed (step S3: NO). finish.

On the other hand, when the overwriting mode or the double-sided mode is set (step S3: YES), the control unit 11 determines whether or not there is unprocessed image formation (step S4), and when this is not set (step S4). S4: NO), this process is terminated.

On the other hand, when there is unprocessed image formation (step S4: YES), the control unit 11 switches the switching gate G and conveys the paper P to the circulation path R3 (step S5).

Next, the control unit 11 determines whether or not the overwriting mode is set (step S6), and if the overwriting mode is set (step S6: YES), the paper P is imaged by the circulation path R3. It returns to the formation path R1 (step S7), then shifts to the above step S2, and the subsequent processing is repeated.

On the other hand, when the overlay mode is not set (double-sided mode) (step S6: NO), the control unit 11 reverses the reversing roller 27 to convey the paper P to the ADU reversing path R4. After the paper P is returned to the image forming path R1 by the ADU inversion path R4 (step S8), the process proceeds to the above step S2, and the subsequent processing is repeated.

As described above, according to the present embodiment, the image forming unit 10 that forms an image on the paper P, the image forming path R1 that conveys the paper P to the image forming unit 10, and the paper conveying rather than the image forming unit 10. A circulation path R3 that branches from the image forming path R1 downstream in the direction and joins the image forming path R1 so that the image forming surfaces of the paper P are on the same surface upstream of the image forming unit 10 in the paper conveying direction to circulate the paper. And a control unit 11 that circulates the paper P on which the image is formed by the image forming unit 10 by the circulation path R3, and executes the overwriting process of forming an image on the image forming surface by the image forming unit 10.
Therefore, when forming an image on the same surface of the paper P, it is not necessary to set the paper P on which the first image formation is performed in the apparatus again. Therefore, it is possible to reduce the time and effort required to form an image on the same surface of the paper P.

Further, according to the present embodiment, the image forming unit 10 can form an image of a normal color of yellow, magenta, cyan, and black and an image of a special color which is a color other than the normal color on the paper P.
Therefore, it is possible to superimpose images of a plurality of colors including special colors on the same surface of the paper P.

Further, according to the present embodiment, when the control unit 11 executes the overwriting process on one side of the paper P, the control unit 11 forms a white image at the time of forming the first image, and the control unit 11 forms a normal color at the time of forming the other images. Form an image.
Therefore, a white image can be formed as a base for a normal color image.

Further, according to the present embodiment, the control unit 11 executes the overwriting process when the overwriting mode in which the image is formed a plurality of times on the same surface of the paper P is selected.
Therefore, when the overwriting mode is arbitrarily selected by the user, the overwriting process can be executed.

In the above-described embodiment, a case where a solid white image is formed in the first image formation and a normal color image is formed in the second image formation in the overwriting mode has been described as an example. However, a normal color image may be formed in the first image formation, and a white image may be formed in the second image formation.
Further, a normal color image may be formed both the first time and the second time. For example, a monochrome image may be formed in the first image formation, and an image such as red may be formed in the second image formation.

Further, in the above-described embodiment, the configuration for forming a white (W) toner image has been illustrated and described as a special color, but the special color is not limited to white, and other than this, for example, clear (transparent). Etc. may be used.
When the spot color is clear, for example, it is possible to perform processing such as forming a normal color image in the first image formation and forming a solid image (coating) by clearing in the second image formation.
Further, in the above embodiment, the number of image forming units forming the spot color is one, but the configuration may include two or more sets of image forming units forming the spot color of two or more colors.

Further, in the above embodiment, a configuration for forming a toner image of four colors of yellow, magenta, cyan, and black as normal colors has been described as an example, but the normal colors are not limited to this, and other than this. Colors can also be included.
Further, in the above embodiment, the number of image forming units forming the normal color is four, but five or more sets of image forming units forming the normal color of five or more colors may be provided, or three sets may be provided. The following image forming unit may be used.

Further, in the above-described embodiment, the case where the image is formed twice on the same surface of the paper P has been described as an example, but the image may be formed three or more times on the same surface of the paper P. That is, one side of the paper P may be overwritten twice or more.
In that case, for example, a solid white image can be formed in the first image formation, and a normal color image can be formed in the second and subsequent image formations. Alternatively, a solid image (coating) by clearing can be formed in the final image formation, and a normal color image can be formed in other image formation. At this time, the number of image formations of the normal color image may be set according to the texture of the image to be formed, the paper type of the paper P to be used, the basis weight, and the like.
Further, both sides of the paper P may be overwritten once or a plurality of times.

Further, in the above-described embodiment, the configuration in which the merging point 51 and the merging point 52 are provided at distant positions has been described as an example, but the merging point 51 and the merging point 52 may be provided at the same position.
By doing so, the standby position of the next sheet P can be set to the downstream side, and the productivity can be improved.

Further, the paper P applicable to the above-described embodiment may be not only standard paper but also long paper long in the paper transport direction.
When the paper P is a long paper, the paper P is image-formed by, for example, a paper feeding device (not shown) connected to the image forming apparatus 100 or a manual feed tray provided in the image forming apparatus 100. It can be sent out to the route R1.

Further, in the above-described embodiment, an example in which a non-volatile memory, a hard disk, or the like is used as a computer-readable medium for the program according to the present invention has been disclosed, but the present invention is not limited to this example. As another computer-readable medium, a portable recording medium such as a CD-ROM can be applied. A carrier wave is also applied as a medium for providing data of the program according to the present invention via a communication line.

Further, in the above-described embodiment, the electrophotographic image forming apparatus has been described as an example, but the present invention can also be applied to other image forming methods such as an inkjet method.

In addition, the detailed configuration and detailed operation of the image forming apparatus can be appropriately changed without departing from the spirit of the present invention.

100 Image forming device SC Original reading device 10 Image forming unit 10Y, 10M, 10C, 10K, 10W Image forming unit 1Y, 1M, 1C, 1K, 1W Photoreceptor drum 2Y, 2M, 2C, 2K, 2W Charging part 3Y, 3M , 3C, 3K, 3W Optical writing unit 4Y, 4M, 4C, 4K, 4W Developer 5Y, 5M, 5C, 5K, 5W Drum cleaner 6 Intermediate transfer belt 7Y, 7M, 7C, 7K, 7W Primary transfer roller 8 2 Next transfer roller 9 Fixing device 20 Paper transport unit 21 Paper feed tray 22 Paper feed section 23 Intermediate transport roller 24 Loop roller 25 Resist roller 26 Paper discharge tray 27 Reversing roller 28 Intermediate transport roller 51, 52 Confluence point R1 Image formation path R2 Discharge Paper path R3 Circulation path R4 Inversion path G Switching gate 11 Control unit 12 Storage unit 13 Communication unit 14 Operation unit P Paper

Claims (6)

An image forming part that forms an image on paper,
An image forming path for transporting the paper to the image forming section, and an image forming path.
It branches from the image forming path downstream of the image forming section in the paper conveying direction, and joins the image forming path so that the image forming surface of the paper becomes the same surface upstream of the image forming section in the paper conveying direction. A circulation route that circulates paper and
A control unit that circulates the paper on which an image is formed by the image forming unit by the circulation path and executes an overwriting process for forming an image on the image forming surface by the image forming unit.
An inversion path that branches off from the circulation path and joins the image forming path so that the image forming surface of the paper is the back surface of the same surface upstream of the image forming section and circulates the paper.
Equipped with a,
The confluence of the image forming path and the circulation path, an image forming apparatus, wherein the paper conveying direction upstream der Rukoto the merging point between the reverse path and the image forming path. The first aspect of claim 1, wherein the image forming unit can form an image of a normal color including yellow, magenta, cyan, and black and an image of a special color which is a color other than the normal color on paper. Image forming device. When the control unit executes the overwriting process two or more times on one surface of the paper, the control unit forms a spot color image at the time of forming the first image or at the time of forming the last image, and at the time of forming other images, the normal color is formed. The image forming apparatus according to claim 2, wherein an image is formed. Any one of claims 1 to 3, wherein the control unit executes the overwriting process when an overwriting mode for forming an image on the same surface of the paper a plurality of times is selected. The image forming apparatus according to. An image forming section that forms an image on paper, an image forming path that conveys the paper to the image forming section, and an image forming path that branches downstream from the image forming section in the paper conveying direction, and is more than the image forming section. The circulation path that joins the image forming path and circulates the paper so that the image forming surface of the paper becomes the same surface upstream in the paper conveying direction, and the image forming surface of the paper upstream of the image forming portion in the paper conveying direction. An inversion path that joins the image forming path and circulates the paper so as to be the back surface of the same surface and a control unit are provided , and the confluence point between the image forming path and the circulation path is the image forming path. an image forming method in an image forming apparatus Ru paper conveying direction upstream der of the merging point of the reverse path,
The control unit includes a step of circulating the paper on which an image is formed by the image forming unit by the circulation path and executing an overwriting process of forming an image on the image forming surface by the image forming unit. A characteristic image forming method. An image forming section that forms an image on paper, an image forming path that conveys the paper to the image forming section, and an image forming path that branches downstream from the image forming section in the paper conveying direction, and is more than the image forming section. The circulation path that joins the image forming path and circulates the paper so that the image forming surface of the paper becomes the same surface upstream in the paper conveying direction, and the image forming surface of the paper upstream of the image forming portion in the paper conveying direction. An inversion path that joins the image formation path and circulates the paper so as to be the back surface of the same surface is provided , and the confluence point between the image formation path and the circulation path is the image formation path and the inversion path. the computer image forming apparatus Ru paper conveying direction upstream der of the merging point with,
A program for causing the paper on which an image is formed by the image forming unit to be circulated by the circulation path and functioning as a control unit for executing an overwriting process of forming an image on the image forming surface by the image forming unit.

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