JP2018144279A - Image formation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation system which has the small work load in comparison to a case of moving a recording material for formation of an image to another face after formation of an image to one face of the continuous band-like recording material.SOLUTION: An image formation system includes: image formation means which forms an image on one face of a continuous band-like recording material supplied through a first supply path or second supply path; a detection unit which is located between a sheet feeding port and the image formation means and detects the appearance of a mark formed on the face opposite to the face formed with the image by the image formation means; and a control unit which starts formation of the image from a position apart by the distance defined with the detection position of the mark as the reference when forming an image on the face opposite to the formation face of the mark.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming system.

  Patent Document 1 describes a double-sided printing technique in an impact printer that conveys a sheet by inserting protrusions of rollers into punch holes formed on both sides of the sheet that is continuous in a belt shape.

JP 2009-66815 A

The impact printer described in Patent Document 1 employs a method in which the relationship between the paper feed port and the paper discharge port is switched in accordance with the switching of the printing surface, and eliminates the need to move the paper when switching the printing surface.
The above-described method can be realized by incorporating a stacker unit in the main body when the apparatus is small and the paper capacity is small. However, when the apparatus is large and the paper capacity is large, paper is fed from the outside of the printing apparatus. In the case of a device that ejects paper to the outside, when the printing surface is switched, it is necessary to move the paper output to the paper ejection port side to the paper feed port side, which is a burden on the movement of the paper.

  The present invention provides an image forming system with less work load as compared with the case of moving a recording material for forming an image on the other side after forming an image on one side of a continuous recording material in a strip shape. With the goal.

According to a first aspect of the present invention, there is provided an image forming means for forming an image on one side of a recording material continuous in a strip shape supplied through the first supply path or the second supply path, a paper feed port, and the image forming means. And a detection unit that detects the appearance of a mark formed on a surface opposite to the surface on which the image forming unit forms an image, and an image on a surface opposite to the surface on which the mark is formed In the image forming system, the image forming system includes a control unit that starts image formation from a position separated by a distance determined based on the detection position of the mark.
According to a second aspect of the present invention, the load acting on the recording material supplied to the sheet feeding port through the first supply path and the sheet feeding port are supplied to the sheet feeding port through the second supply path. The image forming system according to claim 1, further comprising a first transport mechanism that balances a load acting on the recording material.
A third aspect of the present invention is the image forming system according to the second aspect, wherein the first transport mechanism is detachable from a housing in which the image forming unit is accommodated.
According to a fourth aspect of the present invention, the first transport mechanism is provided when the recording material is supplied from the second supply path even when the recording material is supplied from the first supply path. And a second roller pair for transporting the recording material discharged from the first roller pair to the paper feed port. The image forming system described in the above.
The invention according to claim 5 is the image forming system according to claim 4, wherein the first roller pair is inclined in a direction away from the second roller pair.
A sixth aspect of the present invention is the image forming system according to the first aspect, wherein the detection unit is detachable from a casing in which the image forming unit is accommodated.
According to a seventh aspect of the present invention, there is provided a second transport for transporting the recording material through the second supply path from the side surface on which the paper discharge port is provided to the side surface on which the paper feed port is provided. The image forming system according to claim 1, further comprising a mechanism.
The invention according to claim 8 is the image forming system according to claim 7, wherein the second transport mechanism is detachable from a housing in which the image forming means is accommodated.
The invention according to claim 9 further includes a switching mechanism for switching a discharge direction of the recording material supplied through the first supply path and a discharge direction of the recording material supplied through the second supply path. An image forming system according to claim 1.
A tenth aspect of the present invention is the image forming system according to the ninth aspect, wherein the switching mechanism is detachable from a housing in which the image forming means is accommodated.
According to an eleventh aspect of the present invention, when the control unit finishes the image forming operation for the recording material supplied through the first supply path, the rear end of the page that finally passes through the image forming unit is used. The image forming system according to claim 1, wherein the mark is formed at a position further away from the position by a length determined according to a distance between the detection unit and the image forming unit.
According to a twelfth aspect of the present invention, the control unit is configured to wind up the recording material discharged from a paper discharge port when the recording material is supplied to the paper supply port through the second supply path. More than the sum of the required length and the length required for the conveyance speed of the recording material conveyed through the second supply path to be stable, the position at a position behind the mark formation position. The image forming system according to claim 11, wherein the cutting mechanism is controlled to cut the recording material.
According to a thirteenth aspect of the present invention, when the total number of pages of images formed on both sides of the recording material is an odd number and the formation of the image on the back side starts from the last page, the control unit 2. The image forming system according to claim 1, wherein a blank image is controlled to be formed as the first page of the reverse side.
According to a fourteenth aspect of the present invention, the control unit controls to form a front side image on the opposite side surface after forming the back side image on one side of the recording material. 1. The image forming system according to 1.
According to a fifteenth aspect of the present invention, when the control unit forms a front side image on one side of the recording material and then forms a back side image on the opposite side, the page number is large. The image forming system according to claim 1, wherein the formation of the image on the front side is started from the side.
According to a sixteenth aspect of the present invention, the control unit starts an image forming operation during reception of image data, and image data corresponding to the opposite side surface starts forming an image on the opposite surface. The image forming system according to claim 1, wherein the image forming system is stored in a storage area.
According to a seventeenth aspect of the present invention, there is provided image forming means for forming an image on one side of a continuous recording material supplied in a strip shape supplied through the first supply path or the second supply path, and supply through the first supply path. A first transport mechanism that balances the magnitude of the load acting on the recording material supplied to the paper port and the magnitude of the load acting on the recording material supplied to the paper feed port through the second supply path. A detection unit that is located between the paper feed port and the image forming unit and that detects the appearance of a mark formed on a surface opposite to the surface on which the image forming unit forms an image; A cutting mechanism for cutting the recording material discharged from the opening, and the recording material through the second supply path from the side surface side where the paper discharge port is provided to the side surface side where the paper feeding port is provided. A second transport mechanism for transporting the first supply and the first supply A switching mechanism that switches between a discharge direction of the recording material supplied through a path and a discharge direction of the recording material supplied through the second supply path, and supplying the recording material through the second supply path. And an image forming system including a control unit that starts image formation from a position separated by a distance determined based on a detection position of the mark by the detection unit.

According to the first aspect of the present invention, an image with less work load is formed after forming the image on one side of the continuous recording material in a band shape, compared with the case of moving the recording material for forming the image on the other side. A forming system can be provided.
According to the second aspect of the present invention, since the load acting on the recording material is balanced even if the supply path is different, the difference in image quality due to the difference in formation surface can be reduced.
According to the third aspect of the present invention, the first transport mechanism can be removed when images are not formed on both sides.
According to the fourth aspect of the present invention, since the load acting on the recording material is balanced even if the supply path is different, the difference in image quality due to the difference in formation surface can be reduced.
According to the fifth aspect of the present invention, since the load acting on the recording material is balanced even if the supply path is different, the difference in image quality due to the difference in formation surface can be reduced.
According to the sixth aspect of the present invention, the detection unit can be removed when images are not formed on both sides.
According to the seventh aspect of the present invention, the movement of the recording material after the image is formed on one side can be made unnecessary.
According to the eighth aspect of the present invention, the second transport mechanism can be removed when images are not formed on both sides.
According to the ninth aspect of the present invention, it is possible to avoid the intersection of the conveyance paths of the recording material according to the difference in the image forming surface.
According to the tenth aspect, the switching mechanism can be removed when images are not formed on both sides.
According to the eleventh aspect of the present invention, the positions of the front side image and the back side image can be matched.
According to the twelfth aspect of the present invention, it is possible to make the conveyance conditions for forming an image on one side of a recording material continuous in a belt shape and the conveyance conditions for forming an image on the other side.
According to the thirteenth aspect of the present invention, it is possible to form an image so that the page shift of the image does not occur even when the total number of pages of the image is an odd number.
According to the fourteenth aspect of the present invention, the direction of the surface after paper discharge can be changed.
According to the fifteenth aspect of the present invention, the order of the discharged pages can be changed.
According to the sixteenth aspect of the present invention, it is possible to shorten the total time until image formation on the last page is completed.
According to the seventeenth aspect of the present invention, an image with less work burden is formed as compared with the case where the recording material is moved to form the image on the other surface after the image is formed on one surface of the continuous recording material in a strip shape. A forming system can be provided.

1 is a block diagram showing an example of the overall configuration of an image forming system according to Embodiment 1. FIG. It is a figure explaining the principal part of the internal structure of a 1st conveyance mechanism. 4A and 4B are diagrams illustrating a configuration example of a switching mechanism according to the present embodiment, in which FIG. 5A illustrates a case where a paper P after primary printing is discharged, and FIG. 5B illustrates a case where a paper P after secondary printing is discharged. It is a figure explaining the paper discharge angle. It is a figure explaining the structure of a control part. It is a figure explaining the preparation step for starting double-sided printing. FIG. 4 is a diagram illustrating a state in which a leading end portion of a sheet is guided to a sheet feeding port of the image forming apparatus. It is a figure showing the state which set the front-end | tip part of the paper to the paper holder prepared in the primary discharge location. 5 is a flowchart for explaining processing operations executed by a control unit of the image forming apparatus. FIG. 6 is a diagram for explaining an arrangement relationship of images printed on the front side of a sheet. It is a figure explaining the example of a display of a reset request screen. FIG. 6 is a diagram illustrating a state in which printing on the front side of a sheet is completed and the sheet is wound on a sheet holder. FIG. 6 is a diagram illustrating a state in which a sheet pulled out from a sheet holder is set in a sheet feeding port through a second sheet feeding path and then set in a new sheet holder for winding. FIG. 6 is a diagram for explaining an arrangement relationship of images printed on the back side of a sheet. It is a figure explaining the state which double-sided printing was complete | finished. It is a figure explaining the example of printing operation in the case of carrying out double-sided printing of the image data whose total number of pages is an odd number. It is a figure explaining the example of printing operation in the case of printing a front page after printing a back page. It is a figure explaining the example of printing operation in the case of printing in reverse order from the last page of a front page.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

<Embodiment 1>
<Device configuration>
FIG. 1 is a block diagram illustrating an example of the overall configuration of an image forming system 20 according to the first embodiment.
The image forming system 20 receives image data through communication with the host computer 10, and forms an image on one side of the continuous paper P. The paper P here is an example of a recording material.
In the present embodiment, the paper P is stored in a state of being wound around a paper holder (not shown). The paper P that is wound around the paper holder is called a paper feed roll.

  The image forming system 20 includes an image forming apparatus 21 that forms an image on one side of a sheet P, and is supported by four casters 22. In FIG. 1, only two of the four are shown. The four casters 22 are attached near the four corners of the bottom surface of the image forming apparatus 21. A space is formed between the bottom surface and the floor surface of the image forming apparatus 21 by the four casters 22. This space is used as a part of the second paper feed path used for transporting the paper P. The second paper feed path is an example of a second supply path.

The housing of the image forming apparatus 21 includes a paper feed port 23 for carrying the paper P into the housing and a paper discharge port 24 for carrying the paper P after the image is formed from the housing. Is provided.
The paper supply port 23 and the paper discharge port 24 are formed at facing positions of the housing. For this reason, the paper P carried in from the paper supply port 23 is linearly conveyed inside the housing and discharged from a paper discharge port 24 provided on the opposite side surface.

A printing mechanism 25 is disposed on the conveyance path of the paper P inside the housing.
The printing mechanism 25 is an example of an image forming unit. In the case of the present embodiment, the printing mechanism 25 is disposed at a position higher than the transport path of the paper P, and forms an image on the upper surface side of the transported paper P.
However, the printing mechanism 25 may be disposed at a position below the transport path of the paper P.

  The printing mechanism 25 in the present embodiment includes four image forming units (not shown) corresponding to yellow (Y), magenta (M), cyan (C), and black (K). The four image forming units are arranged in parallel at regular intervals along the transport path. The number of image forming units to be arranged is not limited to four, and may be one or five or more. The colors associated with the image forming unit are not limited to the four colors described above, but may be similar colors with different densities.

  In the case of the present embodiment, an ink jet system that discharges minute droplets toward an object is adopted for each image forming unit. The inkjet image forming unit can form an image on the surface of the paper P in a non-contact manner. In the inkjet method, an image is formed by reciprocating the head in the width direction of the conveyed paper P and a single pass method in which an image is formed with a head longer than the width of the paper P being fixed on the conveyance path. There is a scanning method. In this embodiment, a single path method is adopted.

  However, it is also possible to adopt an electrophotographic system for the printing mechanism 25. The electrophotographic printing mechanism 25 forms an electrostatic latent image by irradiating a laser beam onto the photosensitive drum, a charger that uniformly charges the surface of the photosensitive drum, and the charged photosensitive drum. An optical system unit, a developer for attaching toner to the electrostatic latent image, a transfer unit for transferring the attached toner to the paper P, and fixing for fixing the toner image formed on the paper P by heating and pressing Use a vessel.

Inside the housing of the image forming apparatus 21, a pair of transport rollers 26 that transport the paper P sandwiched from both sides are disposed on the upstream side and the downstream side of the transport path. The conveyance roller pair 26 is composed of two conveyance rollers arranged with a gap that can convey the sheet P from both sides.
In FIG. 1, one pair of transport rollers 26 is disposed near the paper feed port 23 and the paper discharge port 24. However, this arrangement is for explanation, and the arrangement position is not limited to the vicinity of the paper supply port 23 and the paper discharge port 24. Further, the number of the conveying roller pairs 26 arranged in the housing is not limited to two.

A sensor 27 is disposed between the paper feed port 23 and the printing mechanism 25 in the conveyance path in the image forming apparatus 21. The sensor 27 here is an example of a detection unit.
The sensor 27, when forming an image on the surface opposite to the surface on which an image has already been formed (when forming a secondary printing surface for double-sided printing), is the leading edge of the paper P that is carried in from the paper supply port 23. Used to detect landmarks that appear on the side. The position where the printing mechanism 25 starts to form an image is determined based on the position of the mark.

The mark detected by the sensor 27 is formed in the margin of the paper P after the primary printing surface is printed for duplex printing. The sensor 27 is disposed on the opposite side of the printing mechanism 25 across the conveyance path of the paper P in order to detect this mark. That is, the printing mechanism 25 is provided at a position facing the surface opposite to the surface on which the image is formed.
The sensor 27 here is a component necessary when the image forming apparatus 21 is used as a double-sided printing machine. Therefore, it is not necessary when the image forming apparatus 21 is used as a single-sided printing machine. For this reason, the sensor 27 in the present embodiment is configured to be detachable from the housing of the image forming apparatus 21.

A control unit 28 that controls the operation of the entire apparatus is disposed inside the housing of the image forming apparatus 21.
The control unit 28 is an example of a computer, and controls the printing mechanism 25 according to the image data received through the communication with the host computer 10 described above, and forms an image corresponding to the image data on the paper P.
The control unit 28 functions as a functional unit that receives a mark detection signal from the sensor 27 through a signal line (not shown) and determines an image formation start position based on the detection position (or time).

On the side surface of the housing of the image forming apparatus 21 on the side where the paper feed port 23 is arranged, the paper is supplied even if the shape and distance of the paper P supply path from the paper feed roll to the paper feed port 23 are different. A first transport mechanism 29 for adjusting the difference in the magnitude of the load acting on P to fall within a predetermined allowable range is detachably attached.
In other words, the first transport mechanism 29 is disposed on the paper discharge port 24 side and the magnitude of the load acting on the paper P supplied from the paper feed roll disposed on the paper feed port 23 side through the first paper feed path. It operates as a means for balancing the magnitude of the load acting on the paper P supplied from the fed paper roll to the second paper feed path. The first paper feed path is an example of a first supply path.

FIG. 2 is a diagram illustrating a main part of the internal configuration of the first transport mechanism 29.
The first transport mechanism 29 is composed of two transport roller pairs 30A and 30B, and a common supply path for the paper P carried into the paper feed port 23 by the two transport roller pairs 30A and 30B. The operation is performed so that the magnitude of the load acting on the paper P when it is carried into the paper supply port 23 falls within a predetermined range.
The transport roller pair 30A located on the side far from the paper feed port 23 is disposed below the transport roller pair 30B located on the side close to the paper feed port 23.

Here, the conveyance roller pair 30 </ b> A is inclined in a direction in which a straight line connecting the rotation axes of the two conveyance rollers constituting the distance away from the side surface of the image forming apparatus 21 (or from the conveyance roller pair 30 </ b> B). The conveying roller pair 30A here corresponds to the first roller pair.
On the other hand, the conveyance roller pair 30 </ b> B is determined such that a straight line connecting the rotation axes of the two conveyance rollers that constitute the image is parallel to the side surface of the image forming apparatus 21 or within a predetermined angle range. In other words, the transport roller pair 30A is inclined in a direction away from the transport roller pair 30B. The conveyance roller pair 30B here corresponds to the second roller pair.
With this arrangement and inclination, the shape of the path from the two paper feed paths through the transport roller pair 30A to the transport roller pair 30B is a straight line that extends the supply path formed between the transport roller pair 30A and the transport roller pair 30B. It becomes a symmetrical arrangement across 30C.

The two paper feed paths here are the first paper feed path through which the paper P is carried into the first transport mechanism 29 from a relatively near horizontal angle, and the bottom and side surfaces of the image forming apparatus 21. , The second paper feed path through which the paper P is carried into the first transport mechanism 29 from an angle relatively close to the vertical.
The purpose of the arrangement and inclination here is to avoid a situation in which the magnitude of the load acting on the paper P varies greatly depending on the difference between the two paper feeding paths. It is only one form for balancing the load to be done.

Returning to the description of FIG. A second transport mechanism 31 is detachably attached to the lower surface of the image forming apparatus 21.
The second transport mechanism 31 is along a path portion (a part of the second paper feed path) from the side surface of the housing where the paper discharge port 24 is provided to the side surface of the housing where the paper feed port 23 is provided. This is a mechanism for conveying the paper P. The second transport mechanism 31 in the present embodiment includes two transport roller pairs 32A and 32B.

  A paper cutting mechanism 33 that cuts the paper P discharged from the paper discharge port 24 is fixedly attached to the side surface of the casing of the image forming apparatus 21 on the side where the paper discharge port 24 is disposed. The paper cutting mechanism 33 is used to cut the paper P on which the primary printing surface has been printed in double-sided printing. The paper cutting mechanism 33 is an example of a cutting mechanism.

The paper cut mechanism 33 (or the side surface of the housing of the image forming apparatus 21) has a switching mechanism 34 that switches the discharge direction of the paper P discharged from the paper discharge port 24.
3A and 3B are diagrams illustrating a configuration example of the switching mechanism 34 according to the first embodiment. FIG. 3A illustrates a case where the paper P after the primary printing is discharged, and FIG. 3B illustrates a paper after the secondary printing. The discharge angle when discharging P will be described.
In the case of the present embodiment, the switching mechanism 34 includes two plates 35A and 35B and a rotary shaft 36, and the two plates 35A and 35B connected by a member (not shown) are rotatable so that the rotary shaft 36 can rotate. Attached to.

The paper P is conveyed so as to be guided in a space sandwiched between the two plates 35A and 35B.
The shape of the plates 35A and 35B may be any shape that can switch the carry-out direction of the paper P by switching these attachment angles, and need not be a specific shape or structure.

<Detailed configuration of control unit>
Next, a detailed configuration of the control unit 28 will be described.
FIG. 4 is a diagram illustrating the configuration of the control unit 28.
The control unit 28 includes a CPU (Central Processing Unit) 40, a ROM (Read Only Memory) 41 in which programs executed by the CPU 40 are stored, and a RAM (Random Access Memory) 42 used as a work area of the CPU 40. These constitute a general computer.

The CPU 40 also functions as a data processing unit through program execution. The CPU 40 as a data processing unit separates the received image data into a set of page images formed on the primary printing surface and a set of page images formed on the secondary printing surface, and printing on each printing surface A process of rearranging the page images in order is executed.
The control unit 28 also has a communication interface 43. The communication interface 43 is used for communication with an external device. For example, the communication interface 43 is used for communication with the host computer 10 described above, communication with a terminal device (not shown), and the like.

The control unit 28 also has a display unit interface 44. The display unit interface 44 is used for communication with a display unit 49 used for displaying a user interface screen or the like. As the display unit 49, a liquid crystal display, an organic EL display (electroluminescence display), or the like is used.
The control unit 28 also has an operation unit interface 45. The operation unit interface 45 is used for communication with the operation unit 50 as an input device. For the operation unit 50, operation buttons, operation keys, a touch panel, and the like are used.

The control unit 28 also includes an HDD (Hard Disk Device) 46 that is an example of a nonvolatile storage device. The CPU 40 reads and writes various data with the HDD 46. For example, image data received from the host computer 10 and a control program are stored in the HDD 46.
The control unit 28 also has a printing mechanism interface 47. The printing mechanism interface 47 is used to drive the printing mechanism 25. The printing mechanism interface 47 controls the image forming operation of the printing mechanism 25 based on the image data given from the CPU 40 as the data processing unit.

<Work and printing operations during printing>
Hereinafter, a printing operation of the image forming system 20 used as a double-sided printing machine will be described.
In the image forming system 20 used as a duplex printing machine, a first transport mechanism 29, a second transport mechanism 31, and a switching mechanism 34 are attached to an image forming apparatus 21 (including a paper cutting mechanism 33). ing.
Incidentally, in the image forming system 20 used as a single-sided printing machine, these accessories are removed from the image forming apparatus 21 (including the paper cutting mechanism 33).

FIG. 5 is a diagram illustrating a preparation stage for starting double-sided printing.
Here, the paper feed roll 55A is arranged at the paper feed position upstream of the image forming system 20 (side of the paper feed port 23). The paper feed roll 55 </ b> A refers to a state in which the paper P is wound around the paper holder 55.
On the other hand, a paper holder 56 for winding the paper P discharged from the paper discharge port 24 at the time of primary printing is arranged at the primary discharge position on the downstream side of the image forming system 20 (the side where the paper discharge port 24 is arranged). Has been.

Subsequently, the user pulls out the paper P from the paper feed roll 55 </ b> A and sets it in the image forming system 20.
FIG. 6 is a diagram illustrating a state in which the leading end portion of the sheet P is guided to the sheet feeding port 23 of the image forming apparatus 21.
Thereafter, the user instructs the paper feed of the paper P introduced from the paper feed port 23 through the display unit 49 and the operation unit 50, and discharges the front end of the paper P to the primary discharge place (placement place of the paper holder 56). To set in the paper holder 56.

FIG. 7 is a diagram illustrating a state in which the leading end portion of the paper P is set in the paper holder 56 prepared in the primary discharge place.
At this stage, the paper P can be taken up by the paper holder 56. Further, the length L1 of the conveyance path from the leading edge of the paper P to the paper holder 56 is stored in the RAM 42 or the HDD 46.
The length L1 here is used when calculating the margin length for secondary printing.

At this stage, the user switches the image forming apparatus 21 to the online state. Thereafter, communication between the host computer 10 and the image forming apparatus 21 becomes possible.
FIG. 8 is a flowchart illustrating processing operations executed by the control unit 28 of the image forming apparatus 21. The control and processing operations here are realized through execution of a program by the CPU 40 of the control unit 28.

First, the control unit 28 receives image data together with a print instruction from the host computer 10 (step 101). In the present embodiment, it is assumed that the total number of pages of image data is six. The control unit 28 stores all the received image data in the RAM 42 and the HDD 46. The control unit 28 responds to the host computer 10 with information indicating that processing is in progress (busy).
In the case of the present embodiment, the control unit 28 selectively forms the page image on the front side on the paper P, and after all the printing on one side is completed, the page image on the back side is selectively formed on the paper P. Shall be formed.

In this case, the control unit 28 extracts surface-side image data from the received image data (step 102). Specifically, page images of page 1, page 3, and page 5 are extracted from all six pages.
During this time, the control unit 28 conveys the paper P by a predetermined distance and prepares for the start of printing of the first page image.
Here, a blank portion (a portion from the leading edge position of the paper P to the first page printing start position) up to the first page printing start position, which is the first page on the front side, is formed after the back side printing is completed. This is the last part output from the system 20.
Accordingly, the length of the margin portion provided at the leading portion of the paper P for printing on the front side is set to be equal to or longer than the transport distance from the printing end position of the last page on the back side to the winding position of the paper P.

FIG. 9 is a diagram illustrating the arrangement relationship of images printed on the front side of the paper P. In the figure, symbol W indicates the width of the paper P, and symbol L1 indicates the length of the margin.
The origin in the figure gives the reference position of the area where the first page on printing is printed. The image of each page is printed based on the origin.

Returning to the description of FIG. When the paper P is conveyed to the area where the image is printed, the control unit 28 starts printing on the front side (step 103). Printing on the first printing surface is primary printing.
In the present embodiment, printing of the first page that is the first page on the front side is started. Subsequently, the control unit 28 determines whether or not printing on the front side has been completed (step 104). While the negative result is obtained, the control unit 28 continues to print the image on the next page and thereafter. For example, as shown in FIG. 9, the third page of image data is printed as the second page on printing, and the fifth page of image data is printed as the third page on printing.

In the case of the present embodiment, a positive result is obtained in step 104 when printing of the third page on printing is completed.
Subsequently, the control unit 28 prints the mark 60 at a position separated by a predetermined length L2 from the rear end of the last page on the front surface side (the third page in printing in the present embodiment) (step 105). .
The image data of the mark 60 is created or prepared on the image forming apparatus 21 side. For example, the image data of the mark 60 is stored in the ROM 41 in advance.
The printing of the mark 60 is not included in the print instruction received from the host computer 10. That is, the generation of the mark 60 is independently executed by the control unit 28 of the image forming system 20 operating as a double-sided printing machine (having received a double-sided printing instruction).

  The length L2 (see FIG. 9) is defined by a value obtained by adding a predetermined margin to the distance between the sensor 27 and an area where an image can be printed by the printing mechanism 25. Since the mark 60 is used to give the printing start position or timing of the first page on the back side, the length L2 should not be less than the distance between the sensor 27 and the area where the image can be printed by the printing mechanism 25. . The margin value is determined in consideration of the distance and time from the detection of the mark 60 to the actual start of image printing. The length L2 is determined regardless of the length of the page to be printed.

When the printing of the mark 60 is completed, the control unit 28 further conveys the paper P by the length L3 (step 106). The length L3 may be a value obtained by adding a margin to the total value of the two lengths L31 and L32 defined below.
The length L31 is a length necessary to bring the paper P, which is in a stationary state at the start of secondary printing, into a state where it can be conveyed at a predetermined printing speed (conveying speed when printing an image). Incidentally, it is not enough to reach a predetermined printing speed, and it is necessary to maintain this state.
The length L32 is a transport distance until the paper P introduced into the paper supply port 23 is guided to the paper holder for winding.
The margin here may be larger than the transport distance of the paper P from the area where the printing mechanism 25 can print to the paper cutting mechanism 33.

  When the transport distance of the paper P after printing the mark 60 is equal to or longer than the length L2 plus the length L3, the control unit 28 stops the transport of the paper P and controls the paper cutting mechanism 33. Then, the paper P is cut (cut) (step 107). Note that the paper P may be cut manually by the user.

When the sheet P is cut, the control unit 28 displays a screen for requesting the resetting of the sheet P on the display unit 49 (step 108).
FIG. 10 is a diagram for explaining a display example of the reset request screen 70. In the reset request screen 70, the fact that printing on the front side has been completed, the request to reset the paper P to the paper feed port 23 for printing on the back side, and the paper P set in the paper feed port 23 are displayed. To the end of the final discharge destination.

FIG. 11 is a diagram illustrating a state in which printing on the front side of the paper P is completed and the paper P is wound around the paper holder 56. A lump of paper P (roll paper 56A) wound around the paper holder 56 becomes a paper feed roll for back side printing.
FIG. 12 is a diagram illustrating a state in which the paper P pulled out from the paper holder 56 is set in the paper supply port 23 through the second paper supply path and then set in a new paper holder 61 for winding. . In FIG. 12, the roll paper 61A formed at the time when the printing on the back side is finished is also virtually represented.
In FIG. 12, a pair of transport rollers 62 is disposed for the purpose of avoiding interference between the paper P discharged from the paper discharge port 24 and transported and the paper P pulled out of the paper holder 56 and transported. However, the conveyance roller pair 62 can be eliminated.

Returning to the description of FIG. When the preparation for printing on the back side is completed, the discharge direction of the switching mechanism 34 is switched upward as compared with the printing on the front side (step 109). This switching is performed so that the transport path of the paper P discharged from the paper discharge port 24 does not interfere with the paper feed roll (roll paper 56A) or the paper P drawn from the paper feed roll. The execution of switching may be controlled by the control unit 28 or manually by the user.
Either the switching of the discharge direction or the display of the reset request screen may be executed first.

After or in parallel with these processes, the control unit 28 extracts the back side image data from the stored image data (step 110). Specifically, page images of 2, 4, and 6 pages are extracted from all 6 pages.
The control unit 28 rearranges the page images. Specifically, rearrangement is performed in the direction of decreasing page numbers from the larger page numbers. This is because the back side printing starts printing from the 6th page corresponding to the back side of the 5th page printed last in the front side printing.

FIG. 13 is a diagram for explaining the arrangement relationship of images to be printed on the back side of the paper P. In FIG. 13, the position of the mark 60 is shown in a state where the paper P is seen through from the direction of the printing mechanism 25.
In back side printing, printing on the front side starts from the second half of the page, so the origin of each page appears in the second half with respect to the transport direction. For this reason, the printing of the image in each page is executed in the reverse direction (from the second half of the page) as in the case of the front surface printing.

Returning to the description of FIG. The control unit 28 monitors the appearance of the mark 60 from the sensor 27 while moving the conveyance speed of the paper P so as to reach a predetermined speed, and determines a position away from the detection position by a distance L2 as a print start position ( Step 111).
The control unit 28 starts printing on the back side from the determined print start position (step 112). Printing on the second printing surface is secondary printing.

  In the present embodiment, printing of the sixth page on the image data is started as the first page on printing. Subsequently, the control unit 28 determines whether or not the printing on the back side has been completed (step 113). While the negative result is obtained, the control unit 28 continues to print the image on the next page and thereafter. For example, as shown in FIG. 13, the fourth page of image data is printed as the second page on printing, and the second page of image data is printed as the third page on printing.

In the case of the present embodiment, an affirmative result is obtained in step 113 when the printing of the third page on printing is completed.
When printing of all the images on the back side is completed, the control unit 28 continues the conveyance of the sheet until the trailing edge of the sheet P is wound around the sheet holder 61 (step 114). When the winding of the paper P is completed, the double-sided printing operation is completed.
FIG. 14 is a diagram illustrating a state where double-sided printing has been completed. In FIG. 14, the paper P on which double-sided printing has been completed is all wound around the paper holder 61 to form a roll paper 61A.

<Summary>
As described above, according to the present embodiment, it is possible to print an image on both sides of the paper P while using one image forming system 20 that prints an image on one side of the continuous paper P in a strip shape. .
In addition, in the case of the present embodiment, the paper holder (roll paper 56A) that is heavier when the paper P is wound is physically moved from the paper discharge port 24 side to the paper feed port 23 side after the front surface printing is completed. There is no need to move to the user, and the user's labor is reduced.

<Embodiment 2>
In the above-described embodiment, the case where the total number of pages corresponding to image data is an even number has been described.
However, there may be a case where the total number of pages corresponding to the image data is an odd number. For example, when the total number of pages is 5, the number of pages on the front side is 3 pages, while the number of pages on the back side is 2.

FIG. 15 is a diagram for explaining an example of a printing operation when duplex printing is performed on image data having an odd total page number. FIG. 15 shows a case where the total number of pages is five.
Also in the present embodiment, the control unit 28 executes the printing operation according to the flowchart described with reference to FIG.
In this case, the control unit 28 extracts the image data of the second page and the fourth page as the back side image data in Step 110 of FIG. Note that the control unit 28 in the present embodiment automatically inserts a blank image 65 as an image to be printed on the back side of the third page on the front side (that is, the first page image for printing on the back side).
By inserting the blank image 65, it is possible to realize printing without page misalignment between the front-side page and the back-side page.

<Embodiment 3>
In the above-described embodiment, the case where the back page is printed after the front page is printed has been described.
However, the front page may be printed after the back page is printed.
FIG. 16 is a diagram for explaining an example of a printing operation when the front page is printed after the back page is printed. FIG. 16 shows a case where the total number of pages is six.

In the case of the present embodiment, the control unit 28 performs the same operation as in FIG. 8 except that the back side image data is extracted in step 102 of FIG. 8 and the front side image data is extracted in step 110. Run.
In the case of this embodiment, the front side page appears on the surface of the roll paper 61A on which the paper P after the double-sided printing is finished.

<Embodiment 4>
In the above-described embodiment, the case where the front page is printed in order from the top page and then the back page is printed has been described.
However, the front page may be printed in reverse order from the last page.
FIG. 17 is a diagram illustrating an example of a printing operation when printing in reverse order from the last page of the front page. FIG. 17 shows a case where the total number of pages is 6.

In the case of the present embodiment, the control unit 28 extracts the image data on the front side in step 102 of FIG. 8, and then arranges so that the last page (that is, 5 pages) of the three extracted pages is the top. Change. In step 110, after the image data on the back side is extracted, rearrangement is performed so that the first page (that is, two pages) of the extracted three pages is the first.
In the case of this embodiment, it is possible to obtain the roll paper 61A in which the page order is reverse to that of the first embodiment.

<Embodiment 5>
In the first embodiment described above, the case where printing is started after all image data is received in step 101 has been described.
However, when the amount of image data is large and it takes time to receive the entire image data, the time until the double-sided printing is completed becomes long.

Therefore, in the case of the present embodiment, the printing operation is started while receiving the image data. For example, when printing is started from the front side for image data having a total number of 100 pages, printing of the front side is started when the first 20 pages are received.
As described above, the control unit 28 reads out an odd page, which is a front-side page, from the storage area and executes printing. Note that the number of pages to be accumulated before starting printing depends on the conveyance speed of the paper P, the image processing speed, and the like.
After the printing on the front side is completed, all the pages on the back side are prepared, and printing is started in the same procedure as in the first embodiment.
As in the present embodiment, by executing the image data reception process and the printing process in parallel, the time until the double-sided printing is completed can be shortened.

<Other embodiments>
Although the embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear from the description of the scope of the claims that various modifications or improvements added to the above embodiment are also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 20 ... Image forming system, 21 ... Image forming apparatus, 22 ... Caster, 23 ... Paper feed port, 24 ... Paper discharge port, 25 ... Printing mechanism, 26, 30A, 30B, 32A, 32B ... Conveying roller pair, 27 ... Sensor , 28 ... control unit, 29 ... first transport mechanism, 31 ... second transport mechanism, 33 ... paper cutting mechanism, 34 ... switching mechanism, 35A, 35B ... plate, 36 ... rotating shaft, P ... paper

Claims (17)

Image forming means for forming an image on one side of a continuous recording material supplied in a strip shape supplied through the first supply path or the second supply path;
A detection unit that is located between a paper feed port and the image forming unit and detects the appearance of a mark formed on a surface opposite to a surface on which the image forming unit forms an image;
An image forming system comprising: a controller configured to start image formation from a position separated by a distance determined based on a detection position of the mark when an image is formed on a surface opposite to the mark formation surface. The load acting on the recording material supplied to the sheet feeding port through the first supply path and the load acting on the recording material supplied to the sheet feeding port through the second supply path The image forming system according to claim 1, further comprising: a first transport mechanism that balances the first and second transport mechanisms.   The image forming system according to claim 2, wherein the first transport mechanism is detachable from a housing in which the image forming unit is accommodated. The first transport mechanism includes:
A first pair of rollers that conveys both sides of the recording material, both when the recording material is supplied from the first supply path and when the recording material is supplied from the second supply path. ,
The image forming system according to claim 2, further comprising: a second roller pair that conveys the recording material discharged from the first roller pair to the paper feed port.   The image forming system according to claim 4, wherein the first roller pair is inclined in a direction away from the second roller pair.   The image forming system according to claim 1, wherein the detection unit is detachable from a housing in which the image forming unit is accommodated. 2. A second transport mechanism that transports the recording material through the second supply path from a side surface on which a paper discharge port is provided to a side surface on which the paper feed port is provided. Image forming system.   The image forming system according to claim 7, wherein the second transport mechanism is detachable from a housing in which the image forming unit is accommodated. The image forming system according to claim 1, further comprising: a switching mechanism that switches a discharge direction of the recording material supplied through the first supply path and a discharge direction of the recording material supplied through the second supply path. .   The image forming system according to claim 9, wherein the switching mechanism is detachable from a housing in which the image forming unit is accommodated.   When the control unit finishes the image forming operation on the recording material supplied through the first supply path, the control unit and the detection unit further rearward from the rear end position of the page that finally passes through the image forming unit. The image forming system according to claim 1, wherein the mark is formed at a position separated by a length determined according to a distance of the image forming unit.   The control unit includes a length necessary for winding the recording material discharged from a paper discharge port when the recording material is supplied to the paper supply port through the second supply path, A cutting mechanism that cuts the recording material at a position that is greater than or equal to the total length required to stabilize the conveyance speed of the recording material conveyed through the two supply paths and that is behind the mark formation position. 12. The image forming system according to claim 11, wherein the image forming system is controlled.   When the total number of pages of the images formed on both sides of the recording material is an odd number and the formation of the back side image starts from the last page, the control unit is configured to start the first side of the recording material on the back side. The image forming system according to claim 1, wherein control is performed so that a blank image is formed as a page.   2. The image forming system according to claim 1, wherein the control unit performs control so as to form a front side image on the opposite side surface after forming a back side image on one side of the recording material.   The control unit forms an image on the front side from the page having a larger page number when forming an image on the back side on the opposite side surface after forming the front side image on one side of the recording material. The image forming system according to claim 1, wherein the image forming system is started.   The control unit starts an image forming operation during reception of image data, and stores image data corresponding to the opposite surface in a storage area until formation of an image on the opposite surface is started. The image forming system described in 1. Image forming means for forming an image on one side of a continuous recording material supplied in a strip shape supplied through the first supply path or the second supply path;
The magnitude of the load acting on the recording material supplied to the paper feed port through the first supply path, and the magnitude of the load acting on the recording material supplied to the paper feed port through the second supply path A first transport mechanism for balancing
A detection unit that is located between the paper feed port and the image forming unit and detects the appearance of a mark formed on a surface opposite to a surface on which the image forming unit forms an image;
A cutting mechanism for cutting the recording material discharged from the paper discharge port;
A second transport mechanism for transporting the recording material through the second supply path from the side surface on which the paper discharge port is provided to the side surface on which the paper feed port is provided;
A switching mechanism that switches between a discharge direction of the recording material supplied through the first supply path and a discharge direction of the recording material supplied through the second supply path;
A control unit configured to start image formation from a position separated by a distance determined based on a detection position of the mark by the detection unit when the recording material is supplied through the second supply path.

Images