JP6880889B2 - Recording material transfer device and image forming device - Google Patents

Description

The present invention relates to a recording material transfer device and an image forming device.

Patent Document 1 discloses an image forming apparatus including a fixing / discharging means for transporting a transfer material at a transfer material transport speed higher than that of a fixing roller.

Japanese Unexamined Patent Publication No. 2005-215410

In an apparatus for transporting a recording material, if the recording material moves while one surface of the recording material is pressed against a member located on the side of the recording material transport path, the recording material is likely to be curled.
An object of the present invention is to reduce curl of a recording material that may occur during transportation of the recording material, as compared with a configuration in which the recording material easily moves while one surface of the recording material presses against a member other than the recording material. There is.

The invention according to claim 1 has a first contact portion that comes into contact with the recording material, and conveys the recording material in one direction from a first recording material transporting means and the first contact portion. A second recording material transporting means, which is provided at a position deviated from the straight line extending in one direction and transports the recording material transported by the first recording material transporting means, and the first of the recording materials. A means for increasing the slack of a portion located between the recording material transporting means 1 and the second recording material transporting means, and the transport speed of the recording material by the second recording material transporting means. However, since the speed is lower than the transport speed of the recording material by the first recording material transporting means, the portion located between the first recording material transporting means and the second recording material transporting means. After the slack is increased and the transfer of the recording material by the second recording material transporting means is started, and while the recording material is being transported by the first recording material transporting means, the conveying speed of the recording material according to the second recording medium conveying means is a recording material conveying device you increase.
According to the second aspect of the present invention, a guide member for guiding the recording material conveyed by the first recording material conveying means is provided beside the straight line extending in one direction from the first contact portion. The recording material conveying device according to claim 1.
According to the third aspect of the present invention, the portion of the recording material located between the first recording material transporting means and the second recording material transporting means is directed away from the guide member. The recording material conveying device according to claim 2 , wherein the recording material is loosened so as to be convex.
According to the fourth aspect of the present invention, among the guide members, the guide surface for guiding the recording material is such that the first contact portion and the second recording material transporting means come into contact with the recording material. The recording material conveying device according to claim 2 or 3 , which is provided in a certain direction of the straight line extending in one direction from the first contact portion with respect to the straight line connecting the contact portions.
In the invention according to claim 5 , the first recording material transporting means and the second recording material transporting means are driven by a common drive source, and are driven from the drive source to the first recording material transporting means. The configuration of the transmission mechanism for transmitting the force and the configuration of the transmission mechanism for transmitting the driving force from the drive source to the second recording material transport means are different from each other, so that the second recording material transport means is used. towards the conveying speed of the recording material is a recording material conveying apparatus according to claim 1 which is smaller than the transport speed of the recording material according to said first recording medium conveying means.
The invention according to claim 6 has a first contact portion that comes into contact with the recording material, and conveys the recording material in one direction from a first recording material transporting means and the first contact portion. A second recording material transporting means, which is provided at a position deviated from the straight line extending in one direction and transports the recording material transported by the first recording material transporting means, and the first of the recording materials. The increasing means includes an increasing means for increasing the slack of a portion located between the recording material conveying means 1 and the second recording material conveying means, and the increasing means has a predetermined thickness of the recording material. If it is smaller than that, the portion located between the first recording material transporting means and the second recording material transporting means as compared with the case where the thickness of the recording material is larger than the predetermined thickness. a recording material conveying device Ru increases the slack.
The invention according to claim 7 has a first contact portion that comes into contact with the recording material, and conveys the recording material in one direction from a first recording material transporting means and the first contact portion. The recording material provided at a position deviated from the straight line extending in one direction and conveyed by the first recording material conveying means is conveyed, and the recording material conveying speed by the first recording material conveying means is higher than that of the recording material conveying speed. A second recording material transporting means for transporting the recording material at a small recording material transporting speed is provided , and the second recording material transporting means is used when the thickness of the recording material is smaller than a predetermined thickness. This is a recording material transporting device that transports the recording material at a smaller transport speed than when the thickness of the recording material is larger than the predetermined thickness.
The invention according to claim 8 has a first contact portion that comes into contact with the recording material, and conveys the recording material in one direction from a first recording material transporting means and the first contact portion. A second recording material transporting means, which is provided at a position deviating from the straight line extending in one direction and transports the recording material transported by the first recording material transporting means, is provided, and the first recording material is provided. After the recording material from the material transporting means reaches the second recording material transporting means, the recording material is started to be transported by the second recording material transporting means, or by the second recording material transporting means. After the transport of the recording material is started, the transport speed of the recording material by the second recording material transporting means increases, and the recording material from the first recording material transporting means becomes the second recording material transporting means. When the transfer of the recording material by the second recording material transporting means is started after the arrival of the recording material, the recording is performed after a predetermined time has elapsed after the recording material reaches the second recording material transporting means. When the transfer of the material is started and the thickness of the recording material is smaller than the predetermined thickness, the predetermined time is compared with the case where the thickness of the recording material is larger than the predetermined thickness. It is a recording material transfer device that becomes long.
The invention according to claim 9 has a first contact portion that comes into contact with the recording material, and conveys the recording material in one direction from a first recording material transporting means and the first contact portion. A second recording material transporting means, which is provided at a position deviating from the straight line extending in one direction and transports the recording material transported by the first recording material transporting means, is provided, and the first recording material is provided. After the recording material from the material transporting means reaches the second recording material transporting means, the recording material is started to be transported by the second recording material transporting means, or by the second recording material transporting means. After the transfer of the recording material is started, the transport speed of the recording material by the second recording material transport means increases, and after the transfer of the recording material by the second recording material transport means is started, the second recording material is transferred. When the transport speed of the recording material by the recording material transport means increases, the transport speed of the recording material increases after a predetermined time has elapsed after the recording material reaches the second recording material transport means. When the thickness of the recording material is smaller than the predetermined thickness, the recording material transporting device has a longer predetermined time than when the thickness of the recording material is larger than the predetermined thickness. Is.
According to the tenth aspect of the present invention, a guide member for guiding the recording material conveyed by the first recording material conveying means is provided beside the straight line extending in one direction from the first contact portion. The claim that the portion of the recording material located between the first recording material transporting means and the second recording material transporting means is loosened so as to be convex in the direction away from the guide member. The recording material conveying device according to any one of 7 to 9.
The invention according to claim 11 is the second guide member, in which the guide surface for guiding the recording material is such that the first contact portion and the second recording material transporting means come into contact with the recording material. The recording material conveying device according to claim 10 , which is provided in a certain direction of the straight line extending in one direction from the first contact portion with respect to the straight line connecting the contact portions.
The invention according to claim 12 includes an image forming means for forming an image on a recording material and a recording material transporting device for transporting the recording material, and the recording material transporting device is any one of claims 1 to 11 . It is an image forming apparatus composed of the recording material transporting apparatus described in 1.

According to the invention of claim 1, the curl of the recording material that may occur due to the transportation of the recording material is compared with the configuration in which the recording material is easily moved while one surface of the recording material is pressed against a member other than the recording material. Can be reduced.
According to the second aspect of the present invention, it is possible to prevent the recording material conveyed by the first recording material conveying means from being conveyed in an unintended direction, as compared with the case where the guide member is not provided.
According to the third aspect of the present invention, the portion of the recording material located between the first recording material transporting means and the second recording material transporting means is convex toward the guide member side. The curl of the recording material can be reduced as compared with the case of loosening.
According to the invention of claim 4 , it is possible to reduce the curl of the recording material that may occur due to the transportation of the recording material, as compared with the configuration in which the recording material easily moves while one surface of the recording material presses against the guide member. ..
According to the fifth aspect of the present invention, the transport speed of the recording material in the second recording material transporting means can be made smaller than the transporting speed of the recording material in the first recording material transporting means while reducing the number of drive sources.
According to the invention of claim 6 , curling of a recording material having a small thickness can be suppressed as compared with the case where the slack of the recording material is the same regardless of the thickness of the recording material.
According to the invention of claim 7 , the curl of the recording material that may occur due to the transportation of the recording material is compared with the configuration in which the recording material is easily moved while one surface of the recording material is pressed against a member other than the recording material. Can be reduced.
According to the inventions of claims 8 and 9 , the recording material may be generated by the transportation of the recording material, as compared with the configuration in which the recording material is easily moved while one surface of the recording material is pressed against other members other than the recording material. Curl can be reduced.
According to the invention of claim 10 , the curl of the recording material can be reduced as compared with the case where the recording material is loosened so as to be convex toward the guide member side.
According to the invention of claim 11 , it is possible to reduce the curl of the recording material that may occur due to the transportation of the recording material, as compared with the configuration in which the recording material easily moves while one surface of the recording material presses against the guide member. ..
According to the invention of claim 12 , the curl of the recording material that may occur due to the transportation of the recording material is compared with the configuration in which the recording material is easily moved while one surface of the recording material is pressed against a member other than the recording material. Can be reduced.

It is an overall block diagram of an image forming apparatus. It is a figure explaining the fixing device and the discharge roll. It is a figure which showed the slack which occurs in the paper. (A) and (B) are diagrams showing the paper transport speed in the discharge roll and the paper transport speed in the fixing device. (A) and (B) are diagrams showing the paper transport speed in the discharge roll and the paper transport speed in the fixing device. It is a figure which showed an example of the fixing device which is not provided with a guide member. It is a figure which showed the other arrangement example of a discharge roll and a fixing device.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is an overall configuration diagram of the image forming apparatus 1.
The image forming apparatus 1 is a so-called tandem type color printer, and includes an image forming unit 10 as an example of an image forming means. The image forming unit 10 forms an image on paper P, which is an example of a recording material, based on the image data of each color.
Further, the image forming apparatus 1 is provided with a control unit 30 and an image processing unit 35. The control unit 30 is composed of a program-controlled CPU (Central Processing Unit), and controls each functional unit provided in the image forming apparatus 1. The image processing unit 35 performs image processing on image data from a personal computer (PC) 3, an image reading device 4, or the like.

The image forming unit 10 is provided with four image forming units 11Y, 11M, 11C, 11K (hereinafter, collectively simply referred to as "image forming unit 11") arranged in parallel at regular intervals. ing.
Each image forming unit 11 has the same configuration except for the toner stored in the developing device 15 (described later). Each image forming unit 11 forms a toner image (image) of yellow (Y), magenta (M), cyan (C), and black (K), respectively.

Each of the image forming units 11 is provided with a photoconductor drum 12, a charger 200 for charging the photoconductor drum 12, and an LED print head (LPH) 300 for exposing the photoconductor drum 12. The photoconductor drum 12 is charged by the charger 200. Further, the photoconductor drum 12 is exposed by the LPH 300, and an electrostatic latent image is formed on the photoconductor drum 12.
Further, each image forming unit 11 is provided with a cleaner (not shown) for cleaning the surface of the photoconductor drum 12 and a developer 15 for developing an electrostatic latent image formed on the photoconductor drum 12.

Further, on the image forming unit 10, each color toner image formed by the photoconductor drum 12 is transferred to the intermediate transfer belt 20, and each color toner image formed by the photoconductor drum 12 is sequentially transferred to the intermediate transfer belt 20. A primary transfer roll 21 for (primary transfer) is provided.
Further, the image forming unit 10 has a secondary transfer roll 22 for batch transferring (secondary transfer) the toner image transferred on the intermediate transfer belt 20 to the paper P, and the secondary transferred toner image on the paper P. A fixing device 40 for fixing is provided.

The fixing device 40 is provided with a fixing roll 41 in which a heating source (not shown) is installed. Further, the fixing device 40 is provided with a pressure roll 43 that is pressed against the fixing roll 41 and pressurizes the paper P together with the fixing roll 41.
The fixing roll 41 is arranged on the right side in the drawing of the paper movement path R1. Further, the fixing roll 41 rotates in the clockwise direction in the drawing by receiving a driving force from a motor (described later).

The pressure roll 43 is arranged on the left side in the drawing of the paper movement path R1. The pressure roll 43 is pressed against the outer peripheral surface of the fixing roll 41 and pressurizes the paper P moving between the fixing roll 41 and the pressure roll 43. In other words, the pressurizing roll 43 pressurizes the paper P moving along the paper moving path R1 passing between the fixing roll 41 and the pressurizing roll 43.
Further, the pressure roll 43 receives a driving force from the fixing roll 41 and rotates in the counterclockwise direction. In other words, the pressure roll 43 follows the fixing roll 41 and rotates in the counterclockwise direction.

In the transport direction of the paper P, a discharge roll 500 is provided on the downstream side of the fixing device 40 to transport (send) the paper P conveyed through the fixing device 40 toward the paper loading unit 1E.
The discharge roll 500 is composed of a drive roll 510 and a driven roll 520 that rotates in response to a driving force from the drive roll 510. In the discharge roll 500, the drive roll 510 rotates with the paper P conveyed from the upstream side sandwiched between the drive roll 510 and the driven roll 520. As a result, the paper P is conveyed to the paper loading unit 1E.

A series of processes in the image forming apparatus 1 will be described.
In the image forming apparatus 1, the image processing unit 35 performs image processing on the image data from the PC 3 and the image reading device 4, and the image data subjected to the image processing is supplied to each image forming unit 11. Then, for example, in the black (K) color image forming unit 11K, the photoconductor drum 12 is charged by the charger 200 while rotating in the direction of arrow A, and emits light based on the image data transmitted from the image processing unit 35. It is exposed by the LPH300.

As a result, an electrostatic latent image relating to the black (K) color image is formed on the photoconductor drum 12. Then, the electrostatic latent image formed on the photoconductor drum 12 is developed by the developing device 15, and a black (K) color toner image is formed on the photoconductor drum 12.
Similarly, in the image forming units 11Y, 11M, 11C, each color toner image of yellow (Y), magenta (M), and cyan (C) is formed.

Each color toner image formed by each image forming unit 11 is electrostatically attracted by the primary transfer roll 21 onto the intermediate transfer belt 20 moving in the direction of arrow B, and each color toner is placed on the intermediate transfer belt 20. A superposed toner image is formed.
The toner image formed on the intermediate transfer belt 20 is conveyed to a position (secondary transfer unit T) where the secondary transfer roll 22 is located as the intermediate transfer belt 20 moves. Then, the paper P is supplied from the paper accommodating unit 1B to the secondary transfer unit T at the timing when the toner image is conveyed to the secondary transfer unit T.

In the secondary transfer unit T, the toner image on the intermediate transfer belt 20 is electrostatically transferred to the conveyed paper P by the transfer electric field formed by the secondary transfer roll 22.
After that, the paper P on which the toner image is electrostatically transferred is peeled off from the intermediate transfer belt 20 and conveyed to the fixing device 40.

In the fixing device 40, the paper P is sandwiched between the rotating fixing roll 41 and the pressure roll 43. As a result, the paper P is pressurized and heated while the paper P is being conveyed, and the toner image on the paper P is fixed on the paper P. Then, the paper P that has been fixed is conveyed to the paper loading unit 1E by the discharge roll 500.
In the discharge roll 500, the paper P is sandwiched between the rotating drive roll 510 and the driven roll 520, and the paper P is sent out to the downstream side. As a result, the paper P moves toward the paper loading unit 1E.

FIG. 2 is a diagram illustrating a fixing device 40 and a discharge roll 500. Note that FIG. 2 shows the fixing device 40 and the discharge roll 500 shown in FIG. 1 in a state of being rotated by about 90 ° in the counterclockwise direction.
The fixing device 40 of the present embodiment is provided with a fixing roll 41 in which a heating source (not shown) is installed. Further, the fixing device 40 is provided with a pressure roll 43 that is pressed against the fixing roll 41 and pressurizes the paper P together with the fixing roll 41.

The fixing roll 41 is composed of, for example, a cylindrical metal member, and rotates clockwise in the drawing by receiving a driving force from the motor M.
The pressure roll 43 is composed of a columnar member. More specifically, the pressure roll 43 is composed of, for example, a columnar substrate and an elastic layer provided on the outer side in the radial direction of the substrate.
The fixing device 40 of the present embodiment functions as the first recording material transporting means, and transports (delivers) the paper P in one direction (hereinafter, referred to as “one-way 2A”) indicated by the arrow 2A in the drawing.

Specifically, the fixing device 40 that functions as the first recording material conveying means has a contact portion N (an example of the first contact portion) that contacts the paper P conveyed from the upstream side, and this contact. At the portion N, the paper P is brought into contact with the paper P conveyed from the upstream side, and the paper P is sent out in one direction 2A. In other words, the fixing device 40 comes into contact with the paper P at a contact portion where the fixing roll 41 and the pressure roll 43 come into contact with each other, and sends the paper P to the downstream side.
Further, the one-way 2A is a tangent line to the outer peripheral surface of the fixing roll 41 and the outer peripheral surface of the pressure roll 43, and is a direction in which the tangent line passing through the contact portion N extends, and the fixing device 40 has a direction in which the tangent line extends. Paper P is sent out toward.

Further, in the present embodiment, a guide wall 49 for guiding the paper P sent out in one direction 2A by the fixing device 40 is provided on the main body side of the image forming apparatus 1.
The guide wall 49 is arranged so that the extending direction of the guide wall 49 and the one-way 2A intersect each other, and guide the paper P so that the paper P sent out by the fixing device 40 faces the discharge roll 500. To do.

The discharge roll 500 as an example of the second recording material transporting means includes a drive roll 510 driven by a motor M and a driven roll 520 that rotates by receiving a driving force from the drive roll 510.
In the present embodiment, the paper P sent out by the fixing device 40 and guided by the guide wall 49 reaches the contact portion N2 (an example of the second contact portion) in which the drive roll 510 and the driven roll 520 come into contact with each other. It is sandwiched between the drive roll 510 and the driven roll 520 at the contact portion N2. Then, the paper P receives a driving force from the driving roll 510 and is conveyed to the downstream side.

Further, in the present embodiment, a guide member 88 for guiding the paper P discharged from the fixing device 40 is provided on the downstream side of the fixing device 40.
The guide member 88 is provided on the side (side) of a straight line 2X extending from the contact portion N of the fixing device 40 in one direction 2A (a straight line 2X extending in one direction 2A through the contact portion N).
More specifically, the guide member 88 is provided on both sides (both sides) of the straight line 2X on the side on which the fixing roll 41 is located.

The guide member 88 peels the paper P from the fixing roll 41 and guides the paper P so that the paper P faces the guide wall 49 (the paper P is guided so that the paper P faces the downstream side in the one-way 2A). ).
In the present embodiment, when the paper P passes through the fixing device 40, the toner image on the paper P becomes an adhesive, and the paper P may stick to the fixing roll 41. The guide member 88 enters between the paper P and the fixing roll 41, and peels the paper P from the surface of the fixing roll 41. Further, the guide member 88 guides the paper P so that the peeled paper P faces the guide wall 49.

More specifically, an image is often not formed at the tip of the paper P in the transport direction, and the tip is often not attached to the fixing roll 41.
The guide member 88 enters between the fixing roll 41 and the tip portion where sticking to the fixing roll 41 is unlikely to occur, and peels the paper P from the surface of the fixing roll 41. Then, the guide member 88 guides the paper P by using the side surface 88A extending along the unidirectional 2A.

Here, in the present embodiment, a straight line 2X extending from the contact portion N in one direction 2A (a straight line 2X passing through the contact portion N toward the downstream side in the one direction 2A and along the one direction 2A) is assumed. The discharge roll 500 is provided at a position deviated from the straight line 2X. Specifically, the discharge roll 500 is provided above the straight line 2X in the figure.
Further, in the present embodiment, of the guide member 88, the side surface 88A (an example of the guide surface) for guiding the paper P has a straight line 2X with respect to the straight line 2Z connecting the contact portion N and the contact portion N2. It is provided in the direction.

Further, in the present embodiment, the transport speed of the paper P by the discharge roll 500 is lower than the transport speed of the paper P by the fixing device 40. In addition, the peripheral speed of the drive roll 510 provided on the discharge roll 500 is smaller than the peripheral speed of the fixing roll 41 provided on the fixing device 40.
As a result, in the present embodiment, the slack in the portion of the paper P located between the fixing device 40 and the ejection roll 500 increases. In other words, in the present embodiment, the slack of the paper P increases after the paper P reaches the discharge roll 500.

When the slack of the paper P increases, the curl of the paper P is less likely to occur.
Specifically, when the slack of the paper P increases, the paper P is less likely to be pressed against the guide member 88, and the paper P is less likely to be curled due to the pressing of the paper P against the guide member 88. Become.
More specifically, when the paper P moves while one surface of the paper P is pressed against the guide member 88, the paper P tends to be curled, but the slack of the paper P increases as in the present embodiment. Then, this pressing against the guide member 88 is less likely to occur, and curl is less likely to occur on the paper P.

Here, the fixing roll 41 and the driving roll 510 can be regarded as increasing means for increasing the slack of the portion of the paper P located between the fixing device 40 and the discharging roll 500. Further, the portion provided with the fixing device 40 and the discharge roll 500 has a function of conveying the paper P which is an example of the recording material, and the portion provided with the fixing device 40 and the discharge roll 500 has a function of conveying the paper P. It can be regarded as a recording material transfer device.

Here, for example, when the transport speed of the paper P by the discharge roll 500 is higher than the transport speed of the paper P by the fixing device 40, the paper P is pulled by the discharge roll 500, and the discharge roll 500 and the fixing device Paper P is stretched between 40 and 40.
In this case, the paper P moves while one side of the paper P is pressed against the guide member 88, and the paper P is likely to be curled. In particular, in the present embodiment, the paper P immediately after leaving the fixing device 40 has heat and is liable to be curled.
On the other hand, in the present embodiment, the paper P is loosened, the pressing of the paper P against the guide member 88 is relaxed, or the pressing of the paper P against the guide member 88 is eliminated, and the paper P is curled. It becomes difficult.

Here, in the present embodiment, as shown in FIG. 2, a motor M is provided, and a first transmission mechanism 44A that transmits a driving force from the motor M to the fixing roll 41 and a driving force from the motor M. Is provided with a second transmission mechanism 44B that transmits the above to the drive roll 510.
In the present embodiment, the fixing roll 41 and the driving roll 510 are driven by the motor M, which is a common driving source.

In the present embodiment, as described above, the transport speed of the paper P by the discharge roll 500 (drive roll 510) and the transport speed of the paper P by the fixing device 40 (fixing roll 41) are different, but the transport speed is different. This difference is made by making the configuration of the first transmission mechanism 44A different from the configuration of the second transmission mechanism 44B.
Specifically, for example, by making the diameter of the gear (not shown) included in the first transmission mechanism 44A different from the diameter of the gear (not shown) included in the second transmission mechanism 44B, the paper P is conveyed. It makes a difference in speed.

FIG. 3 is a diagram showing slack generated in the paper P.
As shown by the broken line 3A in FIG. 3, the slack generated in the paper P occurs so as to be convex toward the direction away from the guide member 88. Further, in the present embodiment, as described above, the slack of the paper P increases, but when the slack increases, the paper P becomes further separated from the guide member 88 as indicated by reference numeral 3B.
In other words, in the present embodiment, the portion of the paper P located between the fixing device 40 and the discharge roll 500 is slackened so as to be convex in the direction away from the guide member 88, and this slack is further increased. To increase. As a result, the paper P is less likely to be pressed against the guide member 88, and the paper P is less likely to be curled.

The transport speed of the paper P by the discharge roll 500 may be maintained at a predetermined speed without changing, or after the transport of the paper P by the discharge roll 500 is started, the paper by the discharge roll 500 may be maintained. The transport speed of P may be increased.
Here, if the transport speed of the paper P by the discharge roll 500 is maintained unchanged, the slack of the paper P becomes excessively large, and the paper P may be strongly pressed against the guide wall 49. .. On the other hand, if the transport speed of the paper P by the drive roll 510 is increased from the middle, the slack of the paper P is reduced or the degree of increase in the slack is reduced, and the paper P is pressed against the guide wall 49. It becomes difficult to get up.

The transfer speed of the paper P by the ejection roll 500 may be uniformly increased regardless of the size of the paper P, and whether or not to increase the transfer speed is determined based on the size of the paper P to be conveyed. You may.
Here, for example, the paper P having a large paper length such as the A3 size paper P has a larger slack than the A4 size paper P, and the paper P is likely to be pressed against the guide wall 49.

Therefore, for example, when a paper P exceeding a predetermined size such as an A3 size paper P is conveyed, the paper conveying speed of the ejection roll 500 is increased from the middle, while the A4 size paper P is conveyed. When paper P smaller than a predetermined size is conveyed, for example, a process that does not increase the paper transfer speed in the discharge roll 500 may be performed.

4 (A), 4 (B), 5 (A), and (B) are diagrams showing the paper transport speed of the discharge roll 500 and the paper transport speed of the fixing device 40.
In FIGS. 4 (A), 4 (B), 5 (A), and (B), the solid line indicates the paper transfer speed in the fixing device 40, and the broken line indicates the paper transfer speed in the ejection roll 500.
In this embodiment, as shown in FIG. 4A, the paper transport speed of the ejection roll 500 is lower than the paper transport speed of the fixing device 40. As a result, as described above, the slack of the paper P increases, and the paper P is less likely to be pressed against the guide member 88.

FIG. 4B is a diagram showing the paper transport speed when the paper transport speed in the discharge roll 500 is increased from the middle as described above.
In this case, as shown in FIG. 4B, the paper P is discharged at the timing after the paper P reaches the discharge roll 500, and at the timing when the predetermined time T has elapsed from the predetermined reference time. The paper transport speed in the roll 500 is increased.
Here, the predetermined reference time may be, for example, the time when the paper P is detected by the paper detection sensor (not shown) provided on the paper transport path.

Here, in the example shown in FIG. 4B, the paper transport speed after increasing the paper transport speed of the discharge roll 500 is the same as the paper transport speed of the fixing device 40. In this case, thereafter, the paper P is conveyed while the amount of slack in the paper P is maintained.
As shown in FIG. 4B, when the paper transport speed in the discharge roll 500 is increased from the middle, the fixing device 40 and the discharge roll 500 are not driven by the common motor M, but for example, fixing. A motor is provided corresponding to each of the device 40 and the discharge roll 400, and the rotation speed of the motor corresponding to the discharge roll 500 is increased from the middle.

FIG. 5A shows another example of the paper transport speed of the discharge roll 500 and the paper transport speed of the fixing device 40.
In the above, the slack of the paper P is increased by making the paper transport speed of the discharge roll 500 smaller than the paper transport speed of the fixing device 40, but in the example shown in FIG. 5 (A), the discharge roll By stopping the discharge roll 500 when the paper P reaches 500, the slack of the paper P is increased.

In the example shown in FIG. 5A, when the paper P that has passed through the fixing device 40 reaches the discharge roll 500, the discharge roll 500 is stopped. On the other hand, the fixing device 40 sequentially feeds out the paper P. As a result, in this case as well, the slack of the paper P increases between the discharge roll 500 and the fixing device 40.
Then, in this example, after a predetermined time T has elapsed from the predetermined reference time, the drive of the discharge roll 500 is started as shown by reference numeral 5A. As a result, the ejection of the paper P by the ejection roll 500 is started.

In the example shown in FIG. 5A, the paper transport speed after the discharge roll 500 is started to be driven is equal to the paper transport speed in the fixing device 40.
However, the present invention is not limited to this, and the paper transport speed after starting the driving of the discharge roll 500 may be lower than the paper transport speed in the fixing device 40, or may be higher than the paper transport speed in the fixing device 40. May be good.

When the paper transport speed of the discharge roll 500 after starting the drive of the discharge roll 500 is equal to the paper transport speed of the fixing device 40, the slack of the paper P is maintained.
Further, when the paper transport speed after starting the driving of the discharge roll 500 is made smaller than the paper transport speed in the fixing device 40, the slack of the paper P gradually increases. Further, when the paper transport speed after starting the driving of the discharge roll 500 is made higher than the paper transport speed in the fixing device 40, the slack of the paper P gradually decreases.

In the example shown in FIG. 5 (A), the case where the discharge roll 500 is stopped when the paper P reaches the discharge roll 500 has been described, but the present invention is not limited to this, and FIG. 5 (B) shows. As shown, when the paper P reaches the discharge roll 500, the discharge roll 500 may be rotated at a low speed. Also in this case, the paper P is sequentially fed from the fixing device 40, which is driven at a higher speed than the discharge roll 500, with respect to the discharge roll 500, which is driven at a low speed, and the slack of the paper P increases.

In the example shown in FIG. 5B, similarly to the above, the paper transport speed by the discharge roll 500 is after the paper P reaches the discharge roll 500 and after a predetermined time T has elapsed from the reference time. To increase.
Also in this case, the paper transport speed of the discharge roll 500 after increasing the paper transport speed may be equal to the paper transport speed of the fixing device 40, or may be smaller than the paper transport speed of the fixing device 40. It may be faster than the paper transport speed in the fixing device 40.

By the way, in the above description, the case where the paper P is pressed against the guide member 88 causes the paper P to be curled, but the curl of the paper P can also occur in the fixing device 40 not provided with the guide member 88. When the process described above is performed, the occurrence of curl can be suppressed even in the fixing device 40 not provided with the guide member 88.

FIG. 6 is a diagram showing an example of a fixing device 40 in which the guide member 88 is not provided.
In this fixing device 40, a fixing belt module 420 is provided in place of the fixing roll 41 described above. The fixing belt module 420 is provided with an endless fixing belt 421 provided so that it can be circulated and moved. Further, the fixing belt module 420 is provided with a pressing member 422 which is arranged inside the fixing belt 421 and presses the pressure roll 43 via the fixing belt 421.

In the fixing device 40, the portion of the pressing member 422 that presses the pressure roll 43 is convex toward the pressure roll 43 side. As a result, in the fixing device 40, the curvature of the portion of the fixing belt 421 that is pressed by the pressing member 422 is larger than that of the other portion.
Then, in this case, when the fixing belt 421 passes through the opposite position of the pressing member 422, the traveling direction of the fixing belt 421 changes abruptly (it changes abruptly so as to face the direction away from the pressure roll 43). In this case, the traveling direction of the fixing belt 421 and the traveling direction of the paper P are different from each other, and the paper P is naturally peeled off from the fixing belt 421.

Here, also in this configuration example, if the paper transport speed in the ejection roll 500 is higher than the paper transport speed in the fixing device 40, the paper P is in a tensioned state (the paper P is stretched). The paper P passes through the facing position of the pressing member 422.
In this case, one side surface of the paper P moves while being pressed against the pressing member 422 (moves while being pressed against the pressing member 422 via the fixing belt 421), as described above. , Paper P is prone to curl.

On the other hand, even in this configuration example, if the paper transport speed in the discharge roll 500 is made smaller than the paper transport speed in the fixing device 40 as described above, the paper P is between the discharge roll 500 and the pressing member 422. The slack is generated, and the paper P is less likely to be pressed against the pressing member 422.
Further, as described above, when the paper P reaches the discharge roll 500, the discharge roll 500 may be stopped or rotated at a low speed. In this case as well, the paper P on the pressing member 422 may be stopped. Is less likely to be pressed.

FIG. 7 is a diagram showing another arrangement example of the discharge roll 500 and the fixing device 40.
In this arrangement example shown in FIG. 7, the guide member 88 is provided on the pressure roll 43 side. In other words, the guide member 88 is provided on both sides (both sides) of the straight line 2X on the side on which the pressure roll 43 is located. Further, in this configuration example, the discharge roll 500 is also provided on the pressure roll 43 side. In other words, the discharge roll 500 is also provided on both sides of the straight line 2X on the side on which the pressure roll 43 is located.

Also in this configuration example, if the paper transport speed of the discharge roll 500 is higher than the paper transport speed of the fixing device 40, the paper P is stretched and one side of the paper P is pressed against the guide member 88.
On the other hand, similarly to the above, when the paper transport speed of the discharge roll 500 is made smaller than the paper transport speed of the fixing device 40, the paper P is loosened and the paper P is less likely to be pressed against the guide member 88. ..
Further, even in this configuration example, when the paper P reaches the discharge roll 500, if the discharge roll 500 is stopped or rotated at a low speed, the paper P is pushed to the guide member 88 in this case as well. It becomes difficult to guess.

(Other)
In the above, the transport control of the paper P is performed without considering the thickness of the paper P, but the transport control of the paper P may be performed in consideration of the thickness of the paper P.
Specifically, for example, when the thickness of the paper P is smaller than the predetermined thickness, the transport control increases the slack as compared with the case where the thickness of the paper P is larger than the predetermined thickness. May be done.

Here, curling of the paper P is more likely to occur as the paper P is thinner. In other words, the curl of the paper P is more likely to occur as the thin paper has a smaller stiffness. In the case of paper P having a thickness smaller than a predetermined thickness, such as thin paper, curling is less likely to occur by increasing the slack.
Here, the information regarding the thickness of the paper P is input by the user through, for example, an operation screen (not shown), and the control unit 30 (see FIG. 1) acquires the information regarding the thickness input on the operation screen. .. Then, the control unit 30 grasps the thickness of the paper P to be conveyed based on the information regarding the thickness. Then, when the thickness of the grasped paper P is smaller than the predetermined thickness, the control unit 30 increases the slack of the paper P.

Specifically, the increase in slack is performed, for example, by reducing the transport speed of the paper P in the discharge roll 500. In addition, the increase in the slack is performed by reducing the transport speed of the paper P in the discharge roll 500 as compared with the case where the thickness of the paper P is larger than the predetermined thickness.

Further, for example, the slack of the paper P is increased by lengthening the time until the transport of the paper P by the discharge roll 500 is started.
More specifically, in the present embodiment, as shown in FIG. 5A, the paper P may be started to be conveyed by the discharge roll 500 after the paper P reaches the discharge roll 500. The increase in the slack of P is performed by increasing this time until the transfer of the paper P by the discharge roll 500 is started.

More specifically, when the paper P thicker than the predetermined thickness is conveyed (normally), the discharge roll 500 is waited for a predetermined time after the paper P reaches the discharge roll 500. On the other hand, when the paper P thinner than the predetermined thickness is conveyed, the predetermined time is lengthened. As a result, when the paper P is thin, the slack of the paper P increases.

Further, for example, the slack of the paper P is increased by increasing the time until the paper transport speed in the discharge roll 500 is increased (the time until the increase in the paper transport speed is started).
Specifically, in the present embodiment, as shown in FIG. 5B, the paper transport speed by the discharge roll 500 may be increased after the transport of the paper P by the discharge roll 500 is started. In this case, if the time until the increase in the paper transport speed of the discharge roll 500 is started is lengthened, the slack of the paper P increases.

More specifically, when the paper P thicker than the predetermined thickness is conveyed (normally), the discharge roll is waited for a predetermined time after the paper P reaches the discharge roll 500. The paper transport speed at 500 is set to increase, while the predetermined time is lengthened when the paper P thinner than the predetermined thickness is transported. As a result, when the paper P is thin, the slack of the paper P increases.

As described above, when increasing the slack of the paper P in the case of thin paper or the like, the fixing device 40 and the discharging roll 500 are not driven by the common motor M, but for example, the fixing device 40 and the discharging device 40 and the discharging. A motor is provided corresponding to each of the rolls 400. Then, the slack is increased or decreased by controlling the rotation of the motor corresponding to the discharge roll 500.
Further, in the above, the increase / decrease in the slack of the paper P is performed by controlling the drive of the discharge roll 500, but the increase / decrease in the slack of the paper P is not limited to the control of the drive of the discharge roll 500. The drive may be controlled, or the drive of both the discharge roll 500 and the fixing device 40 may be controlled.

1 ... Image forming device, 2A ... One direction, 2X ... Straight line, 10 ... Image forming unit, 40 ... Fixing device, 41 ... Fixing roll, 44A ... First transmission mechanism, 44B ... Second transmission mechanism, 88 ... Guide member, 500 ... Discharge roll, 510 ... Drive roll, M ... Motor, N ... Contact part, P ... Paper

Claims (12)

A first recording material transporting means that has a first contacting portion that contacts the recording material and transports the recording material in one direction.
A second recording material transporting means, which is provided at a position deviating from the straight line extending from the first contact portion in one direction and transports the recording material transported by the first recording material transporting means, and a second recording material transporting means.
An increasing means for increasing the slack of a portion of the recording material located between the first recording material transporting means and the second recording material transporting means.
Equipped with a,
Since the transport speed of the recording material by the second recording material transport means is smaller than the transport speed of the recording material by the first recording material transport means, the first recording material transport means The slack in the portion located between the second recording material transporting means is increased, and the slack is increased.
The second recording material is being transported after the recording material is being transported by the second recording material transporting means and while the recording material is being transported by the first recording material transporting means. recording material transport device conveying speed of the recording material by the conveying means you increase. The first aspect of claim 1, wherein a guide member for guiding the recording material to be conveyed by the first recording material conveying means is provided beside the straight line extending from the first contact portion in one direction. Recording material transfer device. Claim that the portion of the recording material located between the first recording material transporting means and the second recording material transporting means loosens so as to be convex in a direction away from the guide member. 2. The recording material transport device according to 2. Among the guide members, the guide surface for guiding the recording material is a straight line connecting the first contact portion and the second contact portion where the second recording material transporting means contacts the recording material. The recording material conveying device according to claim 2 or 3 , which is provided in a certain direction of the straight line extending in the one direction from the first contact portion. The first recording material transporting means and the second recording material transporting means are driven by a common drive source.
The configuration of the transmission mechanism for transmitting the driving force from the drive source to the first recording material transport means and the configuration of the transmission mechanism for transmitting the driving force from the drive source to the second recording material transport means are different from each other. and it has a record of the person of the conveying speed of the recording material according to the second recording medium conveying means, according to claim 1 which is smaller than the transport speed of the recording material according to said first recording medium conveying means Material transfer device. A first recording material transporting means that has a first contacting portion that contacts the recording material and transports the recording material in one direction.
A second recording material transporting means, which is provided at a position deviating from the straight line extending from the first contact portion in one direction and transports the recording material transported by the first recording material transporting means,
An increasing means for increasing the slack of a portion of the recording material located between the first recording material transporting means and the second recording material transporting means.
Equipped with a,
When the thickness of the recording material is smaller than the predetermined thickness, the increasing means can be used with the first recording material transporting means as compared with the case where the thickness of the recording material is larger than the predetermined thickness. wherein the partial record material conveying apparatus Ru increases the slack of which is located between the second recording medium conveying means. A first recording material transporting means that has a first contacting portion that contacts the recording material and transports the recording material in one direction.
The recording material provided at a position deviating from the straight line extending from the first contact portion in one direction and conveyed by the first recording material conveying means is conveyed, and the first recording material conveying means is conveyed. A second recording material transporting means for transporting the recording material at a recording material transporting speed smaller than the recording material transporting speed according to
Equipped with a,
The second recording material transporting means has a smaller transport speed when the thickness of the recording material is smaller than the predetermined thickness, as compared with the case where the thickness of the recording material is larger than the predetermined thickness. A recording material transfer device that transports recording materials in. A first recording material transporting means that has a first contacting portion that contacts the recording material and transports the recording material in one direction.
A second recording material transporting means, which is provided at a position deviating from the straight line extending from the first contact portion in one direction and transports the recording material transported by the first recording material transporting means,
With
After the recording material from the first recording material transporting means reaches the second recording material transporting means, the transporting of the recording material by the second recording material transporting means is started, or the second recording material is transported. After the recording material is transported by the recording material transporting means, the transporting speed of the recording material by the second recording material transporting means increases, and the transporting speed of the recording material increases.
When the recording material from the first recording material transporting means reaches the second recording material transporting means and then the recording material is started to be transported by the second recording material transporting means, the recording material is the first. After a predetermined time has elapsed after reaching the recording material transporting means of 2, the recording material transport is started.
A recording material conveying device in which the predetermined time is longer when the thickness of the recording material is smaller than the predetermined thickness, as compared with the case where the thickness of the recording material is larger than the predetermined thickness. A first recording material transporting means that has a first contacting portion that contacts the recording material and transports the recording material in one direction.
A second recording material transporting means, which is provided at a position deviating from the straight line extending from the first contact portion in one direction and transports the recording material transported by the first recording material transporting means, and a second recording material transporting means.
With
After the recording material from the first recording material transporting means reaches the second recording material transporting means, the transporting of the recording material by the second recording material transporting means is started, or the second recording material is transported. After the recording material is transported by the recording material transporting means, the transporting speed of the recording material by the second recording material transporting means increases, and the transporting speed of the recording material increases.
When the transport speed of the recording material by the second recording material transporting means increases after the transporting of the recording material by the second recording material transporting means is started, the recording material is transferred to the second recording material transporting means. After a predetermined time has passed since the arrival, the transport speed of the recording material increases,
A recording material conveying device in which the predetermined time is longer when the thickness of the recording material is smaller than the predetermined thickness, as compared with the case where the thickness of the recording material is larger than the predetermined thickness. A guide member for guiding the recording material to be conveyed by the first recording material conveying means is provided beside the straight line extending in one direction from the first contact portion.
Claims 7 to 7 to claim, wherein a portion of the recording material located between the first recording material transporting means and the second recording material transporting means is loosened so as to be convex in a direction away from the guide member. The recording material conveying device according to any one of 9. Among the guide members, the guide surface for guiding the recording material is a straight line connecting the first contact portion and the second contact portion where the second recording material transporting means contacts the recording material. The recording material conveying device according to claim 10 , which is provided in a certain direction of the straight line extending in the one direction from the first contact portion. An image forming means for forming an image on a recording material and a recording material transporting device for transporting the recording material are provided, and the recording material transporting device comprises the recording material transporting device according to any one of claims 1 to 11. Image forming apparatus.

Images