JP2022068809A - Image forming device - Google Patents

Abstract

To achieve both quietness and high productivity by adjusting setting of a paper ejection speed in an image forming device to which a post-processing device is connected.SOLUTION: An image forming device to which a post-processing device can be connected includes a conveyance part that inverts image-formed paper and conveys the inverted paper to the post-processing device and control means for setting a conveyance speed when conveying paper to the post-processing device based on paper length information. The control means (1) sets the conveyance speed for each paper to a first conveyance speed when image formation on paper whose length is a first length is continuously executed, (2) sets the conveyance speed for each paper to a second conveyance speed which is slower than the first conveyance speed when the image formation on paper of a second length shorter than the first length is continuously executed, and (3) sets the conveyance speed for each paper to the first conveyance speed when the image formation on paper having the first length and paper having the second length is continuously executed.SELECTED DRAWING: Figure 9

Description

The present invention relates to an image forming apparatus.

It is generally known that an image forming apparatus such as a copying machine or a printer is provided with a paper reversing mechanism. In order to reverse the traveling direction of the paper, the image forming apparatus provided with such a reversing mechanism stops once when the paper is conveyed to an arbitrary position, and then switches back the paper in the opposite direction. When switching back the paper, the leading paper and the trailing paper pass each other, so the transport speed is increased so that the trailing edge of the leading paper and the tip of the trailing paper do not collide.

However, if the paper is ejected to the outside of the machine while the paper transport speed is increased, the operating noise becomes a problem as a harmful effect. In offices these days, there is a strong demand for noise reduction, and it is also required that standards such as Blue Angel meet noise standards suitable for product models. For this reason, at the timing of ejecting the paper to the outside of the machine, the transfer speed is reduced to a level where productivity can be achieved 100%, and the noise is reduced.

By the way, an image forming apparatus is often connected to a post-processing apparatus that performs post-processing such as staples and folding. In such a system, the post-processing device adjusts the transport speed when receiving the paper from the image forming device so as to be the same as the ejection speed of the image forming device.

Japanese Unexamined Patent Publication No. 2006-182475 Japanese Unexamined Patent Publication No. 2007-102192

In the conventional image forming apparatus, the transport speed at the time of ejecting the paper is determined based on the paper size (particularly, the length in the transport and transport direction of the paper). For example, for large size paper such as A3, high productivity is maintained by setting a high transport speed in order to avoid collision between the preceding paper and the succeeding paper at the time of reverse paper ejection. On the other hand, small-sized paper such as A4 can maintain high productivity even if the transport speed is reduced at the time of ejection. Therefore, a low transport speed is set to achieve both high productivity and quietness.

As described above, the paper transport speed when ejected from the image forming apparatus is determined by the size of the paper. As a result, when images of different sizes are continuously formed, the transport speed at the time of ejection may change for each paper.

In the image forming apparatus to which the post-processing apparatus is not connected, there is no particular problem even if the conveying speed at the time of ejection varies from paper to paper. However, in the image forming apparatus to which the post-processing apparatus is connected, the following problems arise when the conveying speed at the time of ejection is switched for each paper.

As described above, the post-processing apparatus adjusts the transport speed at the time of receiving the paper so as to be the same as the ejection speed of the image forming apparatus. Since the post-processing device is an independent drive system separate from the image forming device, when the transport speed at the time of ejection is switched every time the paper size is changed in the image forming device, the transport speed of the post-processing device is changed each time. The shift process must be performed. As a result, downtime occurs due to the switching of the transport speed, and the productivity decreases.

The present invention has been made in view of the above problems, and an object thereof is to improve productivity while realizing noise reduction when performing image formation on papers of different lengths. It is to provide a means to make it.

In order to achieve the above object, the image forming apparatus of the present invention is an image forming apparatus to which a post-processing apparatus can be connected, in which an image forming unit for forming an image on paper and an image forming unit form an image. The paper is based on information on the length in the transport direction of the transport unit that reverses the front and back of the rolled paper and transports the inverted paper to the post-processing device and the paper whose image formation is performed by the image forming unit. The control means comprises a control means for setting a transport speed at which the image is transported to the post-processing device and controlling the transport unit so that the paper is transported to the post-processing device at the set transport speed. , (1) When image formation on the paper whose paper length in the transport direction is the first length is continuously executed, the transport speed for each paper is set to the first transport speed, and (2) When image formation on a second length paper whose paper length in the transport direction is shorter than the first length is continuously executed, the transport speed for each paper is slower than the first transport speed. When the image formation is continuously executed on the paper whose transport speed is set to (3) the paper whose paper length in the transport direction is the first length and the paper whose second length is the second length, for each paper. It is characterized in that the transport speed is set to the first transport speed.

Further, in order to achieve the above object, another image forming apparatus of the present invention includes an image forming unit for forming an image on paper and the image forming unit in an image forming apparatus to which a post-processing apparatus can be connected. Based on the information of the length in the transport direction of the transport unit that reverses the front and back of the image-formed paper and transports the inverted paper to the post-processing device and the paper whose image is formed by the image-forming portion. A control means for setting a transport speed when the paper is conveyed to the post-processing device and controlling the transfer unit so that the paper is conveyed to the post-processing device at the set transfer speed. When the transport speed is different between the papers on which the image is formed, the control means changes the transport speed for each paper on which the image is formed to the fastest of the different transport speeds. It is characterized by doing.

According to the present invention, when image formation is performed on papers of different lengths, it is possible to improve productivity while realizing noise reduction.

Sectional view of image forming apparatus Block diagram showing the control configuration of the image forming apparatus Cross-sectional view of an image forming system with an aftertreatment device The figure which shows the example which passes a plurality of pages in a state where the space between papers is narrow in an image formation system. A diagram showing an example of passing multiple pages in an image forming system with a wide space between papers. Cross-sectional view of the inverted paper ejection part of the image forming apparatus The figure which shows the reversal operation of an image forming apparatus The figure which shows the difference of the paper ejection speed in the reverse paper ejection part Flow chart for explaining the operation of determining the paper ejection speed for each paper The figure which shows an example of the sequence when the printing of 3 pages is executed continuously. A diagram showing an example of a sequence when three-page prints are executed consecutively. A diagram showing an example of a sequence when three-page prints are executed consecutively. Diagram showing an example of a media table A diagram showing an example between paper transport papers Cross-sectional view showing an example between paper transport papers Diagram showing the status of QUE on a page-by-page basis Flow chart (in the case of a configuration that does not have a second paper ejection speed for each paper) The figure which showed an example of the media table in Example 2. The figure which showed an example of the sequence in Example 2. The figure which showed an example between the paper transport papers in Example 2. The figure which shows an example of the sequence in Example 2.

An embodiment of the image forming apparatus according to the present invention will be specifically described.

<Image forming device>
First, the configuration of the image forming apparatus will be described with reference to FIG. The image forming apparatus 100 shown in FIG. 1 is an example of a color image forming apparatus. In FIG. 1, the laser scanners 1Y, 1M, 1C, and 1K are examples of an optical scanning device including a semiconductor laser and a polygon mirror. Further, the photosensitive drums 2Y, 2M, 2C, 2K are examples of an image carrier, and after the outer peripheral surface is charged, the laser beam corresponding to the image signal input to the laser scanners 1Y, 1M, 1C, 1K is emitted. Be irradiated. For convenience of explanation, the photosensitive drum 2 may be used as a representative of the photosensitive drums 2Y, 2M, 2C, and 2K. The same applies to the other image forming process parts.

The charging rollers 3Y, 3M, 3C, and 3K are examples of charging portions that uniformly charge the surface of each photosensitive drum 2. The developing apparatus 4Y, 4M, 4C, 4K is a developing unit that develops a toner image on the photosensitive drums 2Y, 2M, 2C, 2K using toner. The developing sleeves 5Y, 5M, 5C, and 5K are developer carriers rotatably provided in the developing apparatus 4. The developing sleeve 5 conveys a developing agent (toner) of each color to the surface of each photosensitive drum 2. The cleaners 6Y, 6M, 6C, and 6K are cleaning units for cleaning the surface of the photosensitive drum 2. The intermediate transfer belt 7 is an intermediate transfer belt on which toner on the photosensitive drum 2 is transferred, and is rotatably stretched in the clockwise direction of FIG. 1 by a drive roller 9, tension rollers 36a to 36d, and an inner transfer roller 27. ing.

Primary transfer rollers 8Y, 8M, 8C, 8K provided facing the surface of each photosensitive drum 2 are provided on the inner peripheral surface side of the intermediate transfer belt 7. The cleaner 10 is a cleaning unit for cleaning the outer peripheral surface of the intermediate transfer belt 7. The secondary transfer roller 11 is a secondary transfer unit provided on the outer peripheral surface side of the intermediate transfer belt 7 so as to face the inner transfer roller 27. The fixing device 12 is a fixing unit that heat-fixes the toner image formed on the paper. The fixing roller 13 is a fixing roller rotatably provided in the fixing device 12. Reference numeral 14 denotes a pressure roller rotatably provided in the fixing device 12 so as to face the fixing roller 13.

The paper feed cassettes 15a to 15d are detachably provided storage units for storing the recording papers 16a to 16d in the main body of the image forming apparatus 100. In the present embodiment, the identification number of the "feeding stage 1" is set in the paper feed cassette 15a, and plain paper of A4 size is stored. Further, an identification number of "paper feed stage 2" is set in the paper feed cassette 15b, and plain paper of A4R is stored. Further, an identification number of "paper feed stage 3" is set in the paper feed cassette 15c, and plain paper of A3 size is stored. Further, an identification number of "paper feed stage 4" is set in the paper feed cassette 15d, and plain paper of A3 size is stored. In the present embodiment, the A3 paper is an example of paper having a paper length of the first length in the transport direction. Further, A4 paper and A4R paper are examples of paper having a second length in which the paper length in the transport direction is shorter than the first length.

In some cases, the paper cassette 15 will be used as a representative of the paper cassettes 15a to 15d. An optional paper feed cassette (not shown) may be provided outside the main body of the image forming apparatus 100.

The feeding rollers 17a to 17d are feeding rollers that feed the paper toward the image forming unit. In some cases, the feeding rollers 17 will be used as a representative of the feeding rollers 17a to 17d. Reference numeral 18 is a registration roller (hereinafter referred to as a registration roller). Reference numeral 19 is a pre-resist roller. 20a to 20d are intermediate transport rollers. In some cases, the intermediate transfer rollers 20 may be used as a representative of the intermediate transfer rollers 20a to 20d.

The outer discharge roller 21a and the outer discharge roller 21b are a pair of rollers that discharge paper whose traveling direction is reversed by the inverted upper and lower rollers 22a and 22b to the outside of the machine. When the post-processing device is connected to the image forming device 100, the received paper is delivered to the post-processing device. The reversing upper roller 22a and the reversing lower roller 22b are forward / reverse reversible rollers that reverse the traveling direction of the paper on which the toner image is fixed by the fixing device 12 (fixing portion). 23a to 23d are double-sided transport rollers. In the present embodiment, the reversing upper roller 22a, the reversing lower roller 22b, the outer discharge roller 21a, and the outer discharge pre-roller 21b are examples of a transport unit that reverses the front and back of the image-formed paper and conveys the reversed paper. be.

<Image formation operation>
The image forming operation in the image forming portion of the image forming apparatus 100 shown in FIG. 1 will be described. Each photosensitive drum 2 is configured by applying an organic photoconducting layer to the outer periphery of an aluminum cylinder, and a rotational driving force of a motor which is a driving source (not shown) is transmitted to rotate the photosensitive drum 2 in the counterclockwise direction of FIG. The motor rotates each photosensitive drum 2 in the counterclockwise direction of FIG. 1 according to the image forming operation. The surface of each photosensitive drum 2 rotating in the counterclockwise direction of FIG. 1 is uniformly charged by each charging roller 3.

Each laser corresponds to the image data of each color of yellow Y, magenta M, cyan C, and black K sent from the controller 151 shown in FIG. 2 to the surface of each photosensitive drum 2 uniformly charged by each charging roller 3. The laser beam 1a is emitted from the scanner 1. The laser beam 1a is irradiated on the surface of each photosensitive drum 2 and selectively exposed to form an electrostatic latent image.

A developer (toner) of each color supported on the surface of each developing sleeve 5 is supplied to the electrostatic latent image formed on the surface of each photosensitive drum 2, and is developed and visualized as a toner image.

On the other hand, the outer peripheral surface of the intermediate transfer belt 7 is in contact with the surface of each photosensitive drum 2, and is rotationally driven by the drive roller 9 at the time of image formation to rotate in the clockwise direction of FIG. At this time, a primary transfer voltage is applied to each of the primary transfer rollers 8, and the toner image formed on the surface of each photosensitive drum 2 is sequentially transferred and superimposed on the outer peripheral surface of the intermediate transfer belt 7.

The secondary transfer roller 11 comes into contact with the outer peripheral surface of the intermediate transfer belt 7 at the time of image formation, and a secondary transfer voltage is applied to the secondary transfer roller 11. As a result, the toner image primaryly transferred onto the outer peripheral surface of the intermediate transfer belt 7 is collectively transferred to the paper conveyed to the secondary transfer nip portion N1 between the outer peripheral surface of the intermediate transfer belt 7 and the secondary transfer roller 11. Secondary transcription.

The secondary transfer roller 11 is in contact with the outer peripheral surface of the intermediate transfer belt 7 while the toner image primaryly transferred on the outer peripheral surface of the intermediate transfer belt 7 is secondarily transferred to the paper. When the image formation is completed, the intermediate transfer belt 7 is separated from the outer peripheral surface.

The paper on which the toner image is secondarily transferred is conveyed to the fixing device 12 with the toner image facing up by the conveying belt 28. The fixing device 12 heat-melts the transferred toner image while transporting the paper and fixes it on the paper. As shown in FIG. 1, the fixing device 12 includes a fixing roller 13 for heating the paper and a pressure roller 14 for pressing the paper against the fixing roller 13. The fixing roller 13 is formed in a hollow shape, and has a built-in heater (not shown) inside. That is, the paper carrying the toner image is heated and pressurized in the process of being sandwiched and conveyed by the fixing roller 13 and the pressure roller 14, and the toner image is thermally melted and heat-fixed on the surface of the paper.

When the image forming operation is completed, each cleaner 6 cleans the residual toner remaining on the surface of each photosensitive drum 2. Further, the cleaner 10 cleans the residual toner remaining on the outer peripheral surface of the intermediate transfer belt 7. These residual toners are collected in a collection container (not shown).

<Paper transfer operation>
Next, the paper transport operation in the image forming apparatus 100 will be described. The paper selectively fed from the paper cassettes 15a to 15d is fed by the feeding rollers 17, and is separately fed one by one in cooperation with a separation unit (not shown). The fed paper is sandwiched and conveyed by each transfer roller 29 and merges with the transfer path 31. After that, it is conveyed toward the resist pre-roller 19 by each intermediate transfer roller 20 provided in the transfer path 31, and further is sandwiched and conveyed by the resist pre-roller 19 to the nip portion of the resist roller 18 which is temporarily stopped. Attach the tip of the paper. Then, the skew is corrected by being handled by the strength of the waist of the paper.

The resist roller 18 rotates in synchronization with the timing at which the laser beam 1a emitted from each laser scanner 1 irradiates the surface of each photosensitive drum 2 and is exposed. Then, the paper is sandwiched and conveyed by the resist roller 18 and sent out to the secondary transfer nip portion N1 between the outer peripheral surface of the intermediate transfer belt 7 and the secondary transfer roller 11.

Paper is sandwiched and conveyed by the outer peripheral surface of the intermediate transfer belt 7 and the secondary transfer roller 11. As a result, the toner image on the outer peripheral surface of the intermediate transfer belt 7 is collectively transferred to the paper. After that, the paper carrying the toner image is conveyed to the fixing device 12 by the conveying belt 28. The toner image transferred to the paper is heat-fixed by the fixing device 12.

<Straight discharge and reverse discharge>
The paper that has passed through the fixing device 12 may be discharged straight through the transport path 32a, or may be reversely ejected via the transport path 32b, the reverse transport path 33, and the transport path 33a.

When the paper that has passed through the fixing device 12 is discharged straight, the paper that has passed through the fixing device 12 is delivered to the outside discharge roller 21a via the transport path 32a. On the other hand, when the front and back sides of the paper are reversed and ejected, the paper that has passed through the fixing device 12 is delivered to the reversing upper roller 22a provided in the reversing transport path 33 via the transport path 32b.

<Straight discharge>
When the transport path 32a is selected by the rotation of the flapper (not shown), the paper that has passed through the fixing device 12 passes through the transport path 32a and is sandwiched by the external discharge roller 21a so that the surface on which the toner image is fixed faces upward. And is discharged to the outside of the image forming apparatus 100 main body. Alternatively, the paper discharged to the outside of the main body of the image forming apparatus 100 by the external discharge roller 21a is handed over to the post-processing device when the post-processing device is connected, and after a predetermined binding process, drilling process, or the like. Processing is done. After that, the image forming operation is terminated.

<Reverse discharge>
On the other hand, when the front and back of the paper are inverted and the inverted paper is discharged to the outside of the machine, the paper 16 that has passed through the fixing device 12 passes through the transport path 32b and is guided to the reverse transport path 33. The reversing upper roller 22a can rotate forward and reverse. The paper 16 that has passed through the fixing device 12 reaches the reversing upper roller 22a provided in the reversing transport path 33 via the transport path 32b. Then, the reversing upper roller 22a is driven in a normal rotation while holding the paper, and the reversing transport path 33 is reached until the end portion 16 which is the rear end portion of the paper in the traveling direction reaches the vicinity of the upstream of the reversing upper roller 22a. Is conveyed downward in FIG.

After that, the reversing upper roller 22a is driven in a reverse rotation while sandwiching the end portion 16A2 which is the rear end portion in the traveling direction of the paper. Then, the paper is guided to the transport path 33a by reversing the transport direction in the reverse transport path 33, and is delivered to the outer discharge roller 21a and the outer discharge pre-roller 21b.

The paper conveyed from the inverting transfer path 33 by the inverting upper roller 22a, the outer discharge roller 21a, and the outer discharge pre-roller 21b and conveyed through the transfer path 33a is an image in a state where the surface on which the toner image is fixed is inverted downward. It is discharged to the outside of the main body of the forming device 100. Alternatively, the paper discharged to the outside of the image forming apparatus 100 main body by the outer discharge roller 21a and the outer discharge roller 21b is delivered to a post-processing device (not shown) for predetermined post-processing such as binding processing and drilling processing. Is done. After that, the image forming operation is terminated.

<Double-sided printing>
When printing on both sides of the paper, the paper on which the image is formed on the first side passes through the fixing device 12, passes through the transport path 32b, and is guided to the reverse transport path 33. Then, it is delivered to the reversing upper roller 22a and the reversing lower roller 22b provided in the reversing transport path 33. The reversing vertical rollers 22a and 22b can rotate in the forward and reverse directions.

At the time of double-sided printing, the rear end of the paper guided to the reverse transfer path 33 in the traveling direction is conveyed to the vicinity of the reverse lower roller 22b. After that, the reverse rotation lower roller 22b is driven in a reverse rotation, and the paper is guided to the double-sided transport path 35 by a flapper (not shown). Then, it is delivered to the double-sided transport rollers 23a to 23d provided in the double-sided transport path 35. At this time, the first side of the image-formed paper is conveyed upward in the double-sided transfer path 35.

The paper conveyed by the double-sided transfer rollers 23a to 23d provided in the double-sided transfer path 35 joins the transfer path 31 again and is sent out to the resist pre-resist roller 19 and the resist roller 18. When the paper is transferred from the double-sided transfer roller 23d to the resist front roller 19, the front and back surfaces are reversed so that the second side of the paper faces upward.

After that, the paper is sandwiched by the resist roller 18 and conveyed to the secondary transfer nip portion N1 between the outer peripheral surface of the intermediate transfer belt 7 and the secondary transfer roller 11 at a predetermined timing. In the secondary transfer nip portion N1, the toner image carried on the outer peripheral surface of the intermediate transfer belt 7 is secondarily transferred to the paper, and then the toner image is heat-fixed to the paper by the fixing device 12. After that, the paper is guided to the transport path 32a, sandwiched and conveyed by the outside discharge roller 21a, and discharged to the outside of the image forming apparatus 100. Alternatively, the paper is delivered to the post-processing device, a predetermined post-processing is performed, and then the double-sided printing operation is terminated.

FIG. 3 is a cross-sectional view of an image forming system having an image forming apparatus 100 and a post-processing apparatus. This image forming system has a configuration in which an A3 inserter, an A2 folding machine, and an A1 finisher, which are examples of post-processing devices, are connected and connected to the paper ejection port of the image forming device 100. When paper is fed separately from the inserter, it is possible to feed the paper by placing the paper on the A30 insert paper loading section at the top of the A3 inserter.

Further, in the image forming system to which the post-processing device is connected, the paper on which the image is formed is one of the paper ejection ports of the A1 finisher (A10 paper ejection port 1, A11 paper ejection port 2, A12 paper ejection port 3). Is discharged to.

FIG. 4 describes a case in which A4 paper (P1) and A4R (P2) are continuously ejected. The transfer roller A26 and the transfer roller A27 of the A2 folding machine are driven by the motor A25. Further, the transfer roller A36 and the transfer roller A37 of the A3 inserter are driven by the motor A35. Therefore, at the timing when the A4 paper (P1) has passed through the transport roller A36, the next paper, the A4R paper (P2), has already reached the transport roller A37, so that the drive speed of the motor A35 is changed. Can't. This is because the transport rollers A36 and A37 must have the same speed as the external paper ejection roller 21 of the image forming apparatus 100, and the post-processing apparatus and the image forming apparatus are controlled by separate CPUs. be. In such a system controlled by different CPUs, data is exchanged by communication between CPUs, so that motor shifting cannot be performed at the same time.

When the paper ejection speed is changed in paper units (page units), the post-processing device needs to receive at the same speed as the paper ejection speed of the outer ejection roller 21 of the image forming apparatus 100. In the example of FIG. 4, since the space between the paper (P1) and the paper (P2) is narrow, the shift processing between the papers cannot be performed. On the other hand, the example of FIG. 5 describes an example in which the paper (P1) and the paper (P2) are spaced apart from each other (an example in which image formation is not continuously performed). In the example of FIG. 5, when the paper (P1) has passed through the transport roller A36, the next paper (P2) has not reached the transport roller A37. That is, the next paper (P2) can be received by shifting the speed of the motor A35 at the timing when the paper (P1) has passed through the transport roller A36. In this example, the example of the A3 inserter is described, but the same applies to the A2 folding machine and the A1 finisher. Then, the image forming apparatus 100 enables continuous printing by transporting the paper with a space required by each post-processing apparatus. The image forming apparatus 100 acquires the information between the papers required for the post-processing apparatus via the ACC communication unit 171 described later.

Next, the paper ejection portion of the image forming apparatus 100 will be described with reference to the cross-sectional view of the main body paper ejection portion of FIG. As described with reference to FIG. 1, in the case of reverse paper ejection, the paper is accelerated when the paper passes through the fuser 318, and the paper is pulled into the reverse transport path 33 by the reverse upper roller 22a and the reverse lower roller 22b, and the reverse stop position. Stop the rear edge of the paper. When the rear end of the paper is stopped at the reversing stop position, a motor (not shown) reversely drives the reversing upper roller 22a and the reversing lower roller 22b, and conveys the paper to the outer paper ejection rollers 21a and 21b.

A mechanism for switching the transport path at the time of reversal will be described with reference to FIG. 7. First, when the paper is pulled in, the tip of the paper 407 enters the flapper 409 (FIG. 7A). When the tip of the paper 407 enters the flapper 409, the flapper holding spring 406 is pushed up to the left (FIG. 7 (b)). Then, when the paper 407 passes through the flapper 409 and the rear end of the paper reaches 400, which is the reverse rotation stop position, the flapper 409 is pushed back to the right by the flapper holding spring 406 (FIG. 7 (c)). After that, the transfer roller 320 and the reversing roller 321 are driven in reverse to switch the transfer path, and the paper is transferred to the outer paper ejection roller 21 (FIG. 7 (d)).

Next, with reference to FIG. 8, the movement of the paper in the case where the reverse paper ejection speed is different in the case of A4R will be described. In the example of FIGS. 8 (a) to 8 (c), the case where (4) of the A4R paper is inverted and ejected at a speed of 380 mm / s, and then the A4 paper is inserted into the inverted portion in (5) is described. I am doing. On the contrary, in the example of FIGS. 8 (d) to 8 (f), (4) of A4R paper is inverted and ejected at a speed of 500 mm / s, and then A4 paper is inserted into the inverted portion in (5). The case is described.

In FIG. 8A, the reversing drive speed from the reversing stop position 400 starts driving at 380 mm / s. Then, at the time of FIG. 8B, the next A4 paper of (5) has entered the reversing transport path 33 even though the paper of (4) has not been removed. Then, in FIG. 8C, the paper of (5) cannot be pulled in and buckles at the position of the transport roller 320.

On the contrary, in FIG. 8D, the reversing drive speed from the reversing stop position 400 is 500 mm / s. Then, at the time of FIG. 8 (e), the paper of (4) has passed through the transfer roller 320, and the next A4 sheet of (5) is conveyed to the reverse transfer path 33. Then, in FIG. 8 (f), the transport roller 320 is in a state where the paper of (5) can be accepted.

This is because the time for passing through the reverse transfer path 33 changes depending on the paper length during the reverse paper ejection operation. For example, for large size paper such as A3, high productivity is maintained by setting a high transport speed in order to avoid collision between the preceding paper and the succeeding paper at the time of reverse paper ejection. On the other hand, small-sized paper such as A4 can maintain high productivity even if the transport speed is reduced at the time of ejection. Therefore, a low transport speed is set to achieve both high productivity and quietness. As described above, the paper transport speed at the time of ejection from the image forming apparatus is determined by the paper length. In order to achieve 100% productivity in reverse paper ejection, in the present embodiment, the system controller 151 acquires information on the paper feed stage and paper size information with reference to FIG. 13, and the basis weight and size of the paper. It is possible to set different paper ejection speeds (conveyance speeds) according to the above.

In the example of FIG. 13, plain paper of A4 is stored in the first stage of the paper feed stage (paper feed cassette 15a), and 100% productivity is realized at a speed of 380 mm / s when discharging at low speed. It is possible to do. A4R plain paper is stored in the second stage of the paper feed stage (paper feed cassette 15b), and it is possible to achieve 100% productivity at a speed of 500 mm / s when discharging at low speed. be. Further, plain paper of A3 is stored in the third stage of the paper feed stage (paper feed cassette 15c), and the speeds of both low-speed paper discharge and high-speed paper discharge are the same 642 mm / s. It is possible to achieve 100% productivity at this speed.

In the case of the image forming apparatus 100 in the present embodiment, 100% productivity is 70 ppm (ppm = number of output sheets per minute) in the case of A4 paper, 49.5 ppm in the case of A4R paper, and 49.5 ppm in the case of A3 paper. , 35 ppm. As described above, in the present embodiment, the productivity is determined by the paper length.

FIG. 2 is a block diagram showing an example of a control configuration of the image forming apparatus 100. The system controller 151 includes a CPU 151a, a ROM 151b, and a RAM 151c. Further, the system controller 151 includes an image processing unit 112, an operation unit 152, an analog / digital (A / D) converter 153, a high voltage control unit 155, a motor control device 157, 158, sensors 159, an AC driver 160, and an ACC communication unit. It is connected to 171. The system controller 151 can send and receive data and commands to and from each connected unit. The image processing unit 112 stores image data and reads data, and has a role of storing original reading data during COPY operation, receiving image data such as FAX and PDL, and outputting images.

The CPU 151a reads and executes the program stored in the ROM 151b. The RAM 151c is a volatile memory for storing various data, and stores various data such as a set value for the high voltage control unit 155, a command value for the motor control device 157, and information received from the operation unit 152. The system controller 151 transmits the setting data required for image processing in the image processing unit 112 to the image processing unit 112. Further, the system controller 151 receives the signal from the sensors 159 and sets the set value of the high voltage control unit 155 based on the received signal. The high-voltage control unit 155 supplies the voltage required for the high-voltage unit 156 (charger, developer, transfer charger, etc.) according to the set value set by the system controller 151.

The motor control device 157 drives and controls each motor in response to a command output from the CPU 151a. The A / D converter 153 receives the detection signal detected by the thermistor 154 for detecting the temperature of the fixing heater 161, converts the detection signal from an analog signal to a digital signal, and transmits the detection signal to the system controller 151. The system controller 151 controls the AC driver 160 based on the digital signal received from the A / D converter 153. The AC driver 160 controls the fixing heater 161 so that the temperature of the fixing heater 161 becomes a temperature required for performing the fixing process. The fixing heater 161 is a heater used for the fixing process, and is included in the fixing device 318.

The system controller 151 displays an operation screen for the user to set the type of paper to be used (hereinafter referred to as paper type) on the display unit provided in the operation unit 152. The system controller 151 receives the information set by the user from the operation unit 152, and controls the operation sequence of the image forming apparatus 100 based on the information set by the user. Further, the system controller 151 transmits information indicating the state of the image forming apparatus to the operation unit 152. The operation unit 152 displays the information received from the system controller 151 on the display unit.

Further, the system controller 151 is connected to the A1 finisher, the A2 folding machine, and the A3 inserter, which are post-processing devices, so as to be communicable via the ACC communication unit 171 and data is exchanged in paper units (page units). I do. By exchanging this data, the paper ejection speed of the image forming apparatus 100 in the paper unit (page unit) is notified.

The post-treatment device receives the notification of the paper ejection speed from the image forming device 100, and in response to the notification, performs the necessary paper spacing notification. The image forming apparatus 100 determines the image formation timing by comparing with the 100% productive paper spacing according to the information of the received paper spacing notification. The image formation timing is determined so that the required paper space is secured for the preceding page during continuous printing. Then, when the required paper space notified from the post-treatment device requires more paper space than when the productivity is 100%, the post-treatment device is notified by waiting for that time and starting image drawing. Guarantees the required paper space.

<Determination of paper ejection speed>
The paper ejection speed determination operation for each paper (page), which is a characteristic part of the present embodiment, will be described. The operation content of the paper ejection speed determination operation differs between the image forming apparatus having a configuration in which the paper ejection speed is 2nd speed (low speed / high speed) for each paper and the image forming apparatus having a configuration not having 2nd speed. Therefore, the examples will be described in two parts.

[1] Example 1 (operation for determining the paper ejection speed in a configuration having two paper ejection speeds for each paper)
Using the flowchart of FIG. 9, a paper ejection speed determination operation in a configuration having two paper ejection speeds for each paper will be described. In addition, an explanation will be given while also using an event sequence diagram. The event sequence diagram of FIG. 10 is a diagram when three pages of prints are continuously executed. Since the image is stored in the image processing unit 112, the image processing unit 112 notifies the system controller 151 of a page information advance notification event (hereinafter referred to as advance information notification) on a page-by-page basis. Further, the advance information notification includes information on the paper feed source, that is, information on which paper feed stage the paper is fed from. The system controller 151 sets the paper ejection speed when the paper is ejected from the image forming apparatus 100 to the outside of the machine from the paper feed stage information included in the received advance information notification, with reference to the table of FIG. After the prior information notification, the image processing unit 112 notifies the system controller 151 of the page confirmation notification on a page-by-page basis when the image data can be transferred as print data. Since the image memory (not shown) has only one page, the fact that it can be transferred as print data indicates that the image data is expanded in the image memory, and the image transfer is performed. When it is finished, it is a mechanism to expand the next image data.

Further, the image forming apparatus 100 notifies the post-treatment apparatus (A1, A2, A3) of the set paper ejection speed by a PaperLatch signal. Upon receiving the notification, the post-processing device determines whether or not it is necessary to secure more space for the receipt on a page-by-page basis. The PaperLatch signal is a signal for notifying the post-treatment device of the paper information to be discharged, and it is possible to notify the post-processing device of the paper ejection speed. The post-processing device determines whether paper space is required, and if no waiting time is required, notifies the system controller 151 with a parameter of 0. If waiting time is required, the required time is notified as a parameter (usually, notification is in ms order). The system controller 151 receives the response signal of the PaperLatch signal from the post-processing device, and when the waiting time is 0, immediately notifies the image processing unit 112 of the image transfer start event. When a waiting time is required, the system controller 151 notifies the image processing unit 112 of the image transfer start event after the required time has elapsed.

Upon receiving the image transfer start event, the image processing unit 112 inputs the image data as print data to the optical scanning device 311 including the semiconductor laser and the polygon mirror, as described with reference to FIG. As a result, page-based image drawing processing is performed according to the instructions of the system controller 151.

Upon receiving the advance information notification, the system controller 151 generates page-based data (hereinafter referred to as QUE) in the RAM 151c as shown in FIG. FIG. 16A shows a state in which the QUE of P1 is registered. By changing the state from this state to FIG. 16 (B) and FIG. 16 (C), P2 and P3 are connected next to the QUE of P1, and the context is understood. A number indicating the state is updated for each QUE, and S = 1 is a state in which the advance information notification is received and the QUE is generated. S = 2 is a state in which page confirmation information has been received. In S = 3, the image transfer start event is notified to the image processing unit 112 on a page-by-page basis as shown in FIGS. 16 (D), 16 (E), and 16 (F). Each QUE is deleted as shown in (G) and (H) when the paper has been ejected.

Based on the above, the flowchart of FIG. 9 will be described. The flowchart of FIG. 9 is a flowchart showing an operation when receiving information on paper on which image formation is performed and setting an ejection speed of each paper based on the information. Each step in this flowchart is executed by the system controller 151.

First, in S11, the system controller 151 determines whether or not there is an unprocessed advance information notification. Specifically, the system controller 151 determines that there is an unprocessed advance information notification when there is a page for which a QUE is not generated as shown in FIG. 16 while receiving the advance information notification event. When it is determined in the determination of S11 that there is an unprocessed advance information notification page, the process proceeds to S12, the system controller 151 generates a QUE, and the state is set to S = 1. Further, the system controller 151 acquires the paper ejection speed according to the paper size information from the table shown in FIG. 13 for the QUE, and sets the conveying speed at the time of low-speed paper ejection. The information on the transport speed set here is temporarily set, and the setting may be changed by executing the processes of S14 to S22 described later.

In the case of FIG. 10, in the first advance information notification, since the paper feed stage is cassette (hereinafter referred to as CST) 1, 380 mm / s is set. Similarly, the second and third prior information notifications are the paper feed stages of CST2, so 500 mm / s is set. After S12, the process proceeds to S13 to determine whether or not there is a confirmation page. As described above, the confirmation page is determined by the system controller 151 based on whether or not the page confirmation notification is received from the image processing unit 112. In the determination of S13, if the system controller 151 determines that the page confirmation notification has been received from the image processing unit 112, the process proceeds to S14. In S14, the system controller 151 confirms the connection state of the post-processing device (any or all of A1, A2, A3), and determines whether or not the post-processing device is connected to the paper ejection port of the image forming device. judge. If it is determined in S14 that the post-processing device (any or all of A1, A2, A3) is connected, the process proceeds to S15.

In S15, the system controller 151 determines whether or not there is a preceding page for the QUE whose page is confirmed in S13. In the example of FIG. 16, in the case of P1 of (A), it is determined that there is no preceding page, and in the case of P2 of (B), it is determined that there is a preceding page because P1 is present as the preceding page. If it is determined in S15 that there is a preceding page, the process proceeds to S16, and the system controller 151 compares the paper ejection speed of the preceding page with the paper ejection speed of the current target page. If it is determined in S16 that the paper ejection speed of the preceding page and the paper ejection speed of the current target page are different, the process proceeds to S17, and the system controller 151 changes the paper ejection speed of the QUE to a high-speed paper ejection speed. And set. In the case of the QUE of P2 (page confirmation notification 2) of FIG. 10, 642 mm / s is set by referring to the high-speed paper ejection speed from the table of FIG. After S17, the process proceeds to S18, and the system controller 151 determines whether or not there is a space between the preceding page (preceding paper) and the current target page (target paper). Here, the case where it is determined that the paper spacing is not open corresponds to the case where the image formation is continuously performed on the preceding paper and the succeeding paper, which will be described later.

There can be two patterns of judgment that there is space between the papers. The first pattern is when the job submission is delayed. If another job is submitted while printing the preceding job, the print operation is performed as a continuous job in principle. However, depending on the print state of the preceding job, the print operation may not be performed as a continuous job. That is the case when the last image formation start of the preceding job has already been performed at the time of uploading the succeeding job. In such a case, even if printing of the submitted subsequent job is started immediately, the space between the last paper of the preceding job and the first paper of the succeeding job is vacant, and image formation is not performed continuously. .. This case will be described with reference to the sequence diagram of FIG. 12 and the paper position conceptual diagrams of FIGS. 14 and 15.

In FIG. 12, after receiving the advance information notification 1, the page confirmation notification 1 and the image transfer start 1 are subsequently executed. Before the paper ejection of P1 is completed, the next job is submitted, and the advance information notification 2 and the advance information notification 3 are notified from the image processing unit 112 to the system controller 151. The advance information notification 2 is received at the timing when time has elapsed from the image transfer start 1 on the previous page 1. In this case, since the paper is discharged to the post-processing device of page 1 and page 2 in a state where there is a gap between the papers, the paper ejection speed is changed on the post-treatment device side after the page 1 is discharged. Even if it does, it can be absorbed in the empty paper space. On page 2 in this case, it is determined that shifting is possible as the determination of S18. This is because the response to the page confirmation notification 2 to the PaperLatch 2 to the post-processing device has no waiting time. Since page 3 has the same speed as page 2, the waiting time is also zero. At this time, as for the positional relationship of the paper, in FIG. 14, since the space between P1 and P2 is vacant from the positional relationship of the paper, it is determined that the paper ejection speed of P2 may be 500 mm / s. Further, regarding the paper positional relationship in the cross-sectional view of FIG. 15, P1 has started to discharge the paper to the post-processing device, but P2 has a physical distance before reaching the post-processing device. Shows.

The second pattern will be described with reference to the sequence diagram of FIG. FIG. 11 describes a case where paper spacing adjustment is performed on page 2. In the case of FIG. 11, at the time of page confirmation notification 1, the high-speed paper ejection speed is set to 642 mm / s by the process of S22 described later. Subsequently, at the time of page confirmation notification 2, the paper space is adjusted by interrupting, and after the adjustment is completed, there is a case where the paper space is vacant due to the lapse of the adjustment time for page 1. do. Since there is a space between the papers, the response of PaperLatch on page 2 comes with a response of 0 waiting time, and it is determined that shifting is possible in S18. In this case, even if the paper is ejected at the low paper ejection speed, even if the change of the paper ejection speed is changed after the page 1 is ejected, it should be dealt with in the empty paper space. Is possible. This pattern is described on the premise that the paper-to-paper adjustment time is longer than the speed shift time in the post-processing device, but is there a waiting time for the speed shift in the post-processing device due to the exchange of PaperLatch? You may decide whether or not. In this case, a protocol may be used in which a plurality of candidate paper ejection speeds are notified by the exchange of PaperLatch, and the waiting time is notified to each of them by the PaperLatch response. In that case, the protocol is to notify the post-processing device of the determined paper ejection speed.

In the above two patterns, the system controller 151 determines that the speed change is possible in S18, and proceeds to S19. In S19, the system controller 151 changes the setting of the current target page to the low paper ejection speed. To give an example of FIG. 11, on page 2, the paper ejection speed is changed to 642 mm / s by S17, and then the setting is changed to 500 mm / s by S19. After S19, the process proceeds to S20, and the system controller 151 determines whether or not there is a subsequent page. Whether or not there is a subsequent page can be determined by referring to the state of the QUE in FIG. 16 described above. For example, in the case of (C) of FIG. 16, since P3 is a succeeding page when viewed from P2, it can be determined that there is a succeeding page, and when viewed from P3, it can be determined that there is no succeeding page. In the determination of S20, if the system controller 151 determines that there is a succeeding page, it proceeds to S21 and determines the paper ejection speed of the succeeding paper (subsequent page) and the paper ejection speed of the target paper (current page). Compare. In the determination of S21, if the system controller 151 determines that the paper ejection speed of the succeeding page and the paper ejection speed of the current page are different, the process proceeds to S22, and the system controller 151 determines the current target page. , Set to high speed paper ejection speed. After S22, it returns to S11.

Further, in the determination of S21, when the system controller 151 determines that the paper ejection speed of the succeeding page and the paper ejection speed of the current page are the same, the system controller 151 returns to S11 as in the case of S22.

Further, in the determination of S20, if the system controller 151 determines that there is no subsequent page, the system controller 151 returns to S11 as in the case of after S22.

Further, in the determination of S18, when the system controller 151 determines that there is no space between the preceding page and the current target page, the papers capable of shifting are not separated, and the process proceeds to S20.

Further, in the determination of S16, when the system controller 151 determines that the paper ejection speed of the preceding page and the paper ejection speed of the current target page are the same, the process proceeds to S18.

Further, in the determination of S15, if the system controller 151 determines that there is no preceding page, the process proceeds to S20.

Further, in the determination of S13, if the system controller 151 determines that the page confirmation notification has not been received from the image processing unit 112, the system controller 151 proceeds to S30 and determines whether or not there is a output page. The presence / absence of the output page can be determined based on whether or not the post-processing device has notified the completion of the output. By notifying each page of the completion of paper ejection, it is possible to determine whether or not each page has been ejected normally. In the determination of S30, if the system controller 151 determines that there is a paper ejection page, it proceeds to S31 and deletes the QUE data as in the example of FIG. 16 (G). In the example of G, page 1 is deleted. After S31, the process proceeds to S32, and it is determined whether or not all the pages have been ejected. Whether or not all the pages have been ejected can be determined by the fact that all the QUE data in FIG. 16 has disappeared. In the determination of S32, the system controller 151 terminates the job when it is determined that all the pages have been ejected.

On the contrary, in the determination of S32, if the system controller 151 determines that all the pages have not been ejected, the system controller 151 returns to S11.

Further, in the determination of S11, if the system controller 151 determines that there is no page for prior information notification that has not been processed, the system controller 151 proceeds to S13.

Further, if it is determined in S14 that the system controller 151 is not equipped with the post-processing device (any or all of A1, A2, A3), the system controller 151 returns to S11.

As shown in the flowchart of FIG. 9, in the present embodiment, the paper ejection speed (the conveying speed when the paper is conveyed to the outside of the image forming apparatus 100 by the external ejection roller 21) is set as follows. decide. First, it is determined in S14 whether or not the post-processing device is connected. When the post-processing device is not connected (NO in S14), the paper ejection speed is determined based on the paper information set for each paper with reference to the table of FIG. The paper ejection speed determined here is the slowest transport speed among the plurality of transport speeds corresponding to the paper. In the present embodiment, when the aftertreatment device is not connected, the operating noise is reduced by reducing the transport speed to a level at which 100% productivity can be achieved. Therefore, noise reduction can be achieved.

On the other hand, when the post-processing devices (A1 to A3) are connected (YES in S14) and the image formation is continuously performed on a plurality of sheets, if the paper ejection speed is switched for each sheet, the post-processing device will be used. Switching of the transport speed occurs and the total productivity drops. Therefore, in the present embodiment, control is performed so that the paper ejection speed of the target paper is adjusted to the same paper ejection speed as the paper ejection speed of the preceding paper or the succeeding paper when it is different from the paper ejection speed of the preceding paper or the succeeding paper (S16, S17, S21). , S22). Specifically, when it is determined in S15 that the ejection speed of the target paper is different from the ejection speed of the preceding paper, the ejection speed of the target paper is set to the same high transfer speed as the ejection speed of the preceding paper. (S17). Similarly, if it is determined that the ejection speed of the target paper is different from the ejection speed of the succeeding paper, the ejection speed of the target paper is set to a high transfer speed so as to be similar to the ejection speed of the succeeding paper. (S22).

In this way, by controlling the paper ejection speed to be the same as the ejection speed of the preceding paper and the succeeding paper, the speed is changed on the post-processing device side when continuously printing papers having different paper lengths. There is no need to perform processing, and it is possible to prevent a decrease in productivity of the entire system.

For example, in the image forming apparatus to which the post-processing apparatus is connected, when only A3 paper, which is an example of the first length paper, is continuously printed, 642 mm / s, which is an example of the first transport speed, is set. .. Further, when continuously printing only A4 paper, which is an example of the second length paper, 380 mm / s, which is an example of the second transport speed, is set. Further, when continuously printing only A4R paper, which is another example of the second length paper, 500 mm / s, which is another example of the second transport speed, is set.

On the other hand, when printing a plurality of sheets in which A3 sheets and A4 sheets are mixed in succession, the ejection speed of these sheets is set to 642 mm, which is the first transfer speed. Also, when printing a plurality of sheets in which A4 sheets and A4R are mixed continuously, the paper ejection speed of those sheets is set to 642 mm / s, which is the first transport speed. When continuously printing image forming jobs of mixed sizes in this way, the transport speed of each paper is set to a high transport speed with the same transport speed so that the post-processing device does not generate a shift process. As a result, high productivity can be realized when images of different sizes are continuously formed. On the other hand, when the post-processing device is not connected, the optimum paper ejection speed is set for each paper, so that noise reduction can be realized without impairing productivity.

[2] Example 2 (Operation for determining the paper ejection speed in a configuration in which the paper ejection speed is not provided for each paper)
Next, Example 2 will be described. The second embodiment has a configuration in which the paper ejection speed is not set to 2 for each paper. Using the flowchart of FIG. 17, a paper ejection speed determination operation in a configuration in which the paper ejection speed is not provided for each paper will be described. In addition, an explanation will be given while also using an event sequence diagram. The event sequence diagram of FIG. 21 is a diagram when three pages of prints are continuously executed. Since the image is stored in the image processing unit 112, the image processing unit 112 notifies the system controller 151 of a page information advance notification event (hereinafter referred to as advance information notification) on a page-by-page basis. Further, the advance information notification includes information on the paper feed source, that is, information on which paper feed stage the paper is fed from. The system controller 151 sets the paper ejection speed when the paper is ejected from the image forming apparatus 100 to the outside of the machine from the paper feed stage information included in the received advance information notification, with reference to the table of FIG. After the prior information notification, the image processing unit 112 notifies the system controller 151 of the page confirmation notification on a page-by-page basis when the image data can be transferred as print data. Since the image memory (not shown) has only one page, the fact that it can be transferred as print data indicates that the image data is expanded in the image memory, and the image transfer is performed. When it is finished, it is a mechanism to expand the next image data.

Further, the image forming apparatus 100 notifies the post-treatment apparatus (A1, A2, A3) of the set paper ejection speed by a PaperLatch signal. Upon receiving the notification, the post-processing device determines whether or not it is necessary to secure more space for the receipt on a page-by-page basis. The PaperLatch signal is a signal for notifying the post-treatment device of the paper information to be discharged, and it is possible to notify the post-processing device of the paper ejection speed. The post-processing device determines whether paper space is required, and if no waiting time is required, notifies the system controller 151 with a parameter of 0. If waiting time is required, the required time is notified as a parameter (usually, notification is in ms order). The system controller 151 receives the response signal of the PaperLatch signal from the post-processing device, and when the waiting time is 0, immediately notifies the image processing unit 112 of the image transfer start event. When a waiting time is required, the system controller 151 notifies the image processing unit 112 of the image transfer start event after the required time has elapsed.

Upon receiving the image transfer start event, the image processing unit 112 inputs the image data as print data to the optical scanning device 311 including the semiconductor laser and the polygon mirror, as described with reference to FIG. As a result, page-based image drawing processing is performed according to the instructions of the system controller 151.

Upon receiving the advance information notification, the system controller 151 generates page-based data (hereinafter referred to as QUE) in the RAM 151c as shown in FIG. FIG. 16A shows a state in which the QUE of P1 is registered. By changing the state from this state to FIG. 16 (B) and FIG. 16 (C), P2 and P3 are connected next to the QUE of P1, and the context is understood. A number indicating the state is updated for each QUE, and S = 1 is a state in which the advance information notification is received and the QUE is generated. S = 2 is a state in which page confirmation information has been received. In S = 3, the image transfer start event is notified to the image processing unit 112 on a page-by-page basis as shown in FIGS. 16 (D), 16 (E), and 16 (F). Each QUE is deleted as shown in (G) and (H) when the paper has been ejected.

Based on the above, the flowchart of FIG. 17 will be described. The flowchart of FIG. 17 is a flowchart showing an operation when receiving information on paper on which image formation is performed and setting an ejection speed of each paper based on the information. Each step in this flowchart is executed by the system controller 151.

First, in S41, the system controller 151 determines whether or not there is an unprocessed advance information notification. Specifically, the system controller 151 determines that there is an unprocessed advance information notification when there is a page for which a QUE is not generated as shown in FIG. 16 while receiving the advance information notification event. When it is determined in the determination of S41 that there is an unprocessed advance information notification page, the process proceeds to S42, the system controller 151 generates a QUE, and the state is set to S = 1. Further, the system controller 151 acquires the paper ejection speed according to the paper size information from the table shown in FIG. 18 for the QUE, and sets the conveying speed. The information on the transport speed set here is temporarily set, and the setting may be changed by executing the processes of S44 to S52 described later.

In the case of FIG. 21, the first of the prior information notifications is set to 380 mm / s because the paper feed stage is cassette (hereinafter referred to as CST) 1. Similarly, the second and third prior information notifications are the paper feed stages of CST2, so 500 mm / s is set. After S42, the process proceeds to S43 to determine whether or not there is a confirmation page. As described above, the confirmation page is determined by the system controller 151 based on whether or not the page confirmation notification is received from the image processing unit 112. In the determination of S43, if the system controller 151 determines that the page confirmation notification has been received from the image processing unit 112, the process proceeds to S44. In S44, the system controller 151 confirms the connection state of the post-processing device (any or all of A1, A2, A3), and determines whether or not the post-processing device is connected to the paper ejection port of the image forming device. judge. If it is determined in S44 that the post-processing device (any or all of A1, A2, A3) is connected, the process proceeds to S45.

In S45, the system controller 151 determines whether or not there is a preceding page for the QUE whose page is confirmed in S43. In the example of FIG. 16, in the case of P1 of (A), it is determined that there is no preceding page, and in the case of P2 of (B), it is determined that there is a preceding page because P1 is present as the preceding page. If it is determined in S45 that there is a preceding page, the process proceeds to S46, and the system controller 151 compares the paper ejection speed of the preceding page with the paper ejection speed of the current target page. If it is determined in S46 that the paper ejection speed of the preceding page and the paper ejection speed of the current target page are different, the process proceeds to S47. In S47, the system controller 151 changes the paper ejection speed of the QUE to the faster of the paper ejection speed of the paper of the preceding page and the paper ejection speed of the paper of the current target page. .. When P2 (QUE of page confirmation notification 2) in FIG. 21 is the current target page and P1 (QUE of page confirmation notification 1) is the preceding page, the paper ejection speed of the CST2 paper is obtained from the table of FIG. 500 mm / s is set. After S47, the process proceeds to S48, and the system controller 151 determines whether or not there is a space between the preceding page (preceding paper) and the current target page (target paper). Here, the case where it is determined that the paper spacing is not open corresponds to the case where the image formation is continuously performed on the preceding paper and the succeeding paper, which will be described later.

There can be two patterns of judgment that there is space between the papers. The first pattern is when the job submission is delayed. If another job is submitted while printing the preceding job, the print operation is performed as a continuous job in principle. However, depending on the print state of the preceding job, the print operation may not be performed as a continuous job. That is the case when the last image formation start of the preceding job has already been performed at the time of uploading the succeeding job. In such a case, even if printing of the submitted subsequent job is started immediately, the space between the last paper of the preceding job and the first paper of the succeeding job is vacant, and image formation is not performed continuously. .. This case will be described with reference to the sequence diagram of FIG. 12 and the paper position conceptual diagrams of FIGS. 14 and 15.

In FIG. 12, after receiving the advance information notification 1, the page confirmation notification 1 and the image transfer start 1 are subsequently executed. Before the paper ejection of P1 is completed, the next job is submitted, and the advance information notification 2 and the advance information notification 3 are notified from the image processing unit 112 to the system controller 151. The advance information notification 2 is received at the timing when time has elapsed from the image transfer start 1 on the previous page 1. In this case, since the paper is discharged to the post-processing device of page 1 and page 2 in a state where there is a gap between the papers, the paper ejection speed is changed on the post-treatment device side after the page 1 is discharged. Even if it does, it can be absorbed in the empty paper space. On page 2 in this case, it is determined that shifting is possible as the determination of S48. This is because the response to the page confirmation notification 2 to the PaperLatch 2 to the post-processing device has no waiting time. Since page 3 has the same speed as page 2, the waiting time is also zero. At this time, as for the positional relationship of the paper, in FIG. 14, since the space between P1 and P2 is vacant from the positional relationship of the paper, it is determined that the paper ejection speed of P2 may be 500 mm / s. Further, regarding the paper positional relationship in the cross-sectional view of FIG. 15, P1 has started to discharge the paper to the post-processing device, but P2 has a physical distance before reaching the post-processing device. Shows.

The second pattern will be described with reference to the sequence diagram of FIG. FIG. 19 describes a case where paper spacing adjustment is performed on page 2. In the case of FIG. 19, at the time of page confirmation notification 1, the paper ejection speed is set to 500 mm / s, which is the faster of the paper ejection speeds of the CST1 and CST2 papers, in the process of S52 described later. Will be done. Subsequently, at the time of page confirmation notification 2, the paper space is adjusted by interrupting, and after the adjustment is completed, there is a case where the paper space is vacant due to the lapse of the adjustment time for page 1. do. Since there is a space between the papers, the response of PaperLatch on page 2 comes with a response of 0 waiting time, and it is determined that shifting is possible in S48. In this case, even if the paper is ejected at the same paper ejection speed provided for each paper, or if the change of the paper ejection speed is changed after the page 1 is ejected, the paper is discharged between the empty papers. It is possible to respond. This pattern is described on the premise that the paper-to-paper adjustment time is longer than the speed shift time in the post-processing device, but is there a waiting time for the speed shift in the post-processing device due to the exchange of PaperLatch? You may decide whether or not. In this case, a protocol may be used in which a plurality of candidate paper ejection speeds are notified by the exchange of PaperLatch, and the waiting time is notified to each of them by the PaperLatch response. In that case, the protocol is to notify the post-processing device of the determined paper ejection speed.

In the above two patterns, the system controller 151 determines that the speed change is possible in S48, and proceeds to S49. In S49, the system controller 151 changes the setting of the current target page to the paper ejection speed of the paper. To give an example of FIG. 20, on page 2, the paper ejection speed is set to 642 mm / s by S47, and then set to 500 mm / s by S49. After S49, the process proceeds to S50, and the system controller 151 determines whether or not there is a subsequent page. Whether or not there is a subsequent page can be determined by referring to the state of the QUE in FIG. 16 described above. For example, in the case of (C) of FIG. 16, since P3 is a succeeding page when viewed from P2, it can be determined that there is a succeeding page, and when viewed from P3, it can be determined that there is no succeeding page. In the determination of S50, if the system controller 151 determines that there is a succeeding page, it proceeds to S51 and determines the paper ejection speed of the succeeding paper (subsequent page) and the paper ejection speed of the target paper (current page). Compare. If the system controller 151 determines in S51 that the paper ejection speed of the succeeding page and the paper ejection speed of the current page are different, the process proceeds to S52. In S52, the system controller 151 sets the paper ejection speed of the current target page to the faster of the paper ejection speed of the paper of the current target page and the paper ejection speed of the paper of the subsequent page. And set. After that, it returns to S41.

Further, in the determination of S51, when the system controller 151 determines that the paper ejection speed of the succeeding page and the paper ejection speed of the current page are the same, the system controller 151 returns to S41 as in the case after S52. Further, in the determination of S50, if the system controller 151 determines that there is no subsequent page, the system controller 151 returns to S41 as in the case of after S52.

Further, in the determination of S48, when the system controller 151 determines that there is no space between the preceding page and the current target page, the papers capable of shifting are not separated, and the process proceeds to S50. Further, in the determination of S46, when the system controller 151 determines that the paper ejection speed of the preceding page and the paper ejection speed of the current target page are the same, the process proceeds to S48.

Further, in the determination of S45, if the system controller 151 determines that there is no preceding page, the process proceeds to S50. Further, in the determination of S43, if it is determined that the page confirmation notification has not been received from the image processing unit 112, the system controller 151 proceeds to S60 and determines whether or not there is a output page. The presence / absence of the output page can be determined based on whether or not the post-processing device has notified the completion of the output. By notifying each page of the completion of paper ejection, it is possible to determine whether or not each page has been ejected normally. In the determination of S60, if the system controller 151 determines that there is a paper ejection page, it proceeds to S61 and deletes the QUE data as in the example of FIG. 16 (G). In the example of FIG. 16 (G), page 1 is deleted. After S61, the process proceeds to S62 to determine whether all pages have been ejected. Whether or not all the pages have been ejected can be determined by the fact that all the QUE data in FIG. 16 has disappeared. In the determination of S62, the system controller 151 terminates the job when it is determined that all the pages have been ejected.

On the contrary, in the determination of S62, if the system controller 151 determines that all the pages have not been ejected, the system controller 151 returns to S41.

Further, in the determination of S41, if the system controller 151 determines that there is no page for prior information notification that has not been processed, the system controller 151 proceeds to S43.

Further, if it is determined in S44 that the system controller 151 is not equipped with the post-processing device (any or all of A1, A2, A3), the system controller 151 returns to S41.

As shown in the flowchart of FIG. 17, in the present embodiment, the paper ejection speed (the conveying speed when the paper is conveyed to the outside of the machine of the image forming apparatus 100 by the external ejection roller 21) is set as follows. decide. First, it is determined in S44 whether or not the post-processing device is connected. When the post-processing device is not connected (NO in S44), the paper ejection speed is determined based on the paper information set for each paper with reference to the table of FIG. The paper ejection speed determined here is the transport speed provided for each paper. This transport speed is the minimum speed necessary to achieve 100% productivity. In the present embodiment, when the aftertreatment device is not connected, the operating noise is reduced by reducing the transport speed to a level at which 100% productivity can be achieved. Therefore, noise reduction can be achieved.

On the other hand, when the post-processing devices (A1 to A3) are connected (YES in S44) and the image formation is continuously performed on a plurality of sheets, if the paper ejection speed is switched for each sheet, the post-processing device will be used. Switching of the transport speed occurs and the total productivity drops. Therefore, in the present embodiment, control is performed so that the paper ejection speed of the target paper is adjusted to the same paper ejection speed as the paper ejection speed of the preceding paper or the succeeding paper when it is different from the paper ejection speed of the preceding paper or the succeeding paper (S46, S47, S51). , S52). Specifically, when it is determined in S45 that the ejection speed of the target paper is different from the ejection speed of the preceding paper, the ejection speed of the target paper is determined by the ejection speed of the target paper and the ejection speed of the preceding paper. The speed is set to the faster of the speeds (S47). Similarly, when it is determined that the paper ejection speed of the target paper is different from the paper ejection speed of the succeeding paper, the paper ejection speed of the target paper is the faster of the paper ejection speed of the target paper and the paper ejection speed of the succeeding paper. Set to the speed of the other (S52).

In this way, by controlling the paper ejection speed to be the same as the ejection speed of the preceding paper and the succeeding paper, the speed is changed on the post-processing device side when continuously printing papers having different paper lengths. There is no need to perform processing, and it is possible to prevent a decrease in productivity of the entire system.

For example, in the image forming apparatus to which the post-processing apparatus is connected, when printing only A3 paper continuously, 642 mm / s is set. Further, when printing only A4 paper continuously, 380 mm / s is set. When printing only A4R paper continuously, set 500 mm / s.

On the other hand, when printing a plurality of sheets in which A3 paper and A4 paper are mixed in succession, the ejection speed of those sheets is set to the faster of the ejection speeds of A3 paper and A4 paper. Set to a certain 642 mm. Also, when printing a plurality of sheets in which A4 paper and A4R are mixed in succession, the paper ejection speed of those sheets is the faster of the paper ejection speeds of A4 paper and A4R paper. Set to 500 mm / s. When continuously printing image formation jobs with mixed sizes in this way, the transfer speed of each paper is set to the same transfer speed but higher transfer speed so that the post-processing device does not generate a shift process. .. As a result, high productivity can be realized when images of different sizes are continuously formed. On the other hand, when the post-processing device is not connected, the optimum paper ejection speed is set for each paper, so that noise reduction can be realized without impairing productivity.

(Other examples)
The present invention supplies a program that realizes one or more functions of the above-described embodiment to a system or device via a network or storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by the processing to be performed. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

12 Fixing device 28 Conveying belt 21a External paper ejection roller 21b External paper ejection front roller 22a Inverting upper roller 22b Inverting lower roller 100 Image forming device 151 System controller 151a CPU
156 High-voltage unit (charger, developer, transfer charger, etc.)
311 Optical scanning device including semiconductor laser and polygon mirror 318 Fuser

Claims (7)

An image forming device to which a post-processing device can be connected.
An image forming part that forms an image on paper,
A transport unit that reverses the front and back of the image-formed paper by the image-forming unit and transports the inverted paper to the post-processing device.
Based on the information on the length of the paper on which the image is formed by the image forming unit in the transport direction, the transport speed at which the paper is transported to the post-processing device is set, and the paper is rearranged at the set transport speed. A control means that controls the transport unit so that it is transported to the processing device, and
Have,
The control means is
(1) When image formation on paper having a paper length of the first length in the transport direction is continuously executed, the transport speed for each paper is set to the first transport speed.
(2) When image formation on a second length paper whose paper length in the transport direction is shorter than the first length is continuously executed, the transport speed for each paper is lower than the first transport speed. Set to the second transport speed
(3) When image formation is continuously performed on the paper having the paper length of the first length and the paper having the paper length of the second length in the transport direction, the transport speed for each paper is set to the above. An image forming apparatus characterized in that it is set to a first transport speed. The control means determines the connection state of the post-processing device, and when it is determined that the post-processing device is not connected, images are formed on the first length paper and the second length paper. Is continuously executed, the transport speed for the first length paper is set to the first transport speed, and the transport speed for the second length paper is set to the second transport speed. The image forming apparatus according to claim 1, wherein the image forming apparatus is to be used. When the transport unit is transporting the paper of the second length at the first transport speed and there is a gap with the subsequent paper of the first length, the transport speed of the succeeding paper is determined. The image forming apparatus according to claim 1 or 2, wherein the second transport speed is changed. An image forming device to which a post-processing device can be connected.
An image forming part that forms an image on paper,
A transport unit that reverses the front and back of the image-formed paper by the image-forming unit and transports the inverted paper to the post-processing device.
Based on the information on the length of the paper on which the image is formed by the image forming unit in the transport direction, the transport speed at which the paper is transported to the post-processing device is set, and the paper is rearranged at the set transport speed. A control means that controls the transport unit so that it is transported to the processing device, and
Have,
The control means is
In each paper on which image formation is performed, when the transport speed is different between the papers, the transport speed for each paper on which image formation is performed is changed to the fastest of the different transport speeds. Image forming device. The control means determines the connection state of the post-processing device, and when it is determined that the post-processing device is not connected, the fastest speed when image formation on paper is continuously executed. The image forming apparatus according to claim 4, wherein the image forming apparatus is not changed to. If the transport unit is transporting paper at the transport speed changed to the fastest speed and there is a gap with the succeeding paper, the transport speed of the succeeding paper is changed to the original transport speed. The image forming apparatus according to claim 4 or 5. The image forming portion has a fixing portion for fixing the toner image to the paper, and the conveying portion is provided with a reversing roller capable of forward / reverse rotation for reversing the traveling direction of the paper passing through the fixing portion, and the reversing roller. The image forming apparatus according to any one of claims 1 to 6, further comprising a paper ejection roller for transporting paper whose traveling direction is reversed according to the set transport speed.

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