JP7151066B2 - image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

In Patent Document 1, a plurality of drive rollers and a plurality of paper tension detection units are provided upstream and downstream of the printing unit, and the rotation speed of the drive rollers is changed based on the tension detection result to detect the tension of the continuous paper (web). An apparatus is disclosed for controlling the

Japanese Patent Application Laid-Open No. 2002-60104

In an apparatus having a plurality of transfer sections that sequentially transfer images onto the continuous paper while sandwiching the fed continuous paper, for example, if the distance between the plurality of transfer sections is long, fluctuations in the thickness direction of the continuous paper are constrained. The continuous paper may flap.

SUMMARY OF THE INVENTION It is an object of the present invention to suppress fluttering of the continuous paper between a plurality of transfer sections, as compared with a configuration in which fluctuations in the thickness direction of the continuous paper are not constrained.

In the first mode , a plurality of transfer units for sequentially transferring images to the continuous paper sandwiching the conveyed continuous paper, and a plurality of transfer units disposed between the plurality of transfer units to prevent fluctuations in the thickness direction of the continuous paper. and a restraining part for restraining.

A second aspect includes a plurality of transfer units that sandwich the conveyed continuous paper and sequentially transfer images onto the continuous paper, a contact unit that is disposed between the plurality of transfer units and contacts the continuous paper, Prepare.

In a third aspect , the contact portion has a first contact member that contacts the image surface of the continuous paper and a second contact member that contacts the non-image surface of the continuous paper, and the first contact member and the second contact member sandwich the continuous paper.

In the fourth aspect , the first contact member contacts one end portion and the other end portion of the continuous paper in the width direction that intersects the conveying direction and the thickness direction outside the image forming area.

In the fifth aspect , the first contact member is configured such that, in a state in which the transfer section arranged immediately upstream of the contact section is separated from the continuous paper, the first contact member is provided at one end in the width direction intersecting the conveying direction and the thickness direction of the continuous paper. The continuous paper is separated from the continuous paper in a state in which the continuous paper is sandwiched by the transfer unit disposed immediately upstream of the contact portion.

In a sixth aspect , the contact portion has only a contact member that contacts the non-image surface of the continuous paper.

In the seventh aspect , the contact member makes contact from one end to the other end in a width direction that intersects the conveying direction and the thickness direction of the continuous paper.

In the eighth aspect , the restraining section restrains the variation of the continuous paper in the thickness direction without contacting the continuous paper.

According to the configuration of the first aspect , the flapping of the continuous paper is suppressed compared to the configuration in which the variation in the thickness direction of the continuous paper is not constrained between the plurality of transfer portions.

According to the configuration of the second aspect , the continuous paper is suppressed from fluttering between the plurality of transfer units, compared to the configuration in which the continuous paper is not in contact with the transfer units.

According to the configuration of the third mode , compared to the configuration in which the contact portion contacts only one side of the continuous paper, fluttering of the continuous paper is suppressed.

According to the configuration of the fourth aspect , compared to a configuration in which the first contact member contacts the continuous paper from one end portion to the other end portion in the width direction, image disturbance on the image surface is suppressed.

According to the configuration of the fifth aspect , even when the continuous paper is sandwiched between the transfer sections arranged immediately upstream of the contact section, the first contact member is in contact with the continuous paper, thereby suppressing fluttering of the continuous paper. while suppressing image disturbance on the image plane.

According to the configuration of the sixth mode , compared to a configuration in which the contact portion has only a contact member that contacts the image surface of the continuous paper, image disturbance on the image surface is suppressed.

According to the configuration of the seventh mode , compared with the configuration in which the contact member contacts a part in the width direction, the continuous paper is suppressed from fluttering.

According to the configuration of the eighth aspect , compared to the configuration in which the restraining portion contacts the continuous paper, image disturbance of the continuous paper is suppressed.

1 is a schematic diagram showing the configuration of an image forming apparatus in a 4-color mode; FIG. FIG. 4 is a schematic diagram showing a state in which the first roll contacts the continuous paper in the image forming apparatus in monochrome mode; FIG. 4 is a schematic diagram showing a state in which the first roll is separated from the continuous paper in the image forming apparatus in monochrome mode; It is a top view which shows the structure of the contact part which concerns on a 1st modification. It is a schematic diagram showing the configuration of a contact portion according to a third modification. It is a schematic diagram showing the configuration of a contact portion according to a third modification. It is a schematic diagram showing the configuration of a contact portion according to a fourth modification. It is a schematic diagram showing the composition of the contact portion concerning the fifth modification.

An example of an embodiment according to the present invention will be described below with reference to the drawings.

(Image forming apparatus 10)
First, the configuration of the image forming apparatus 10 according to this embodiment will be described. FIG. 1 is a schematic diagram showing the configuration of an image forming apparatus 10 according to this embodiment.

As shown in FIG. 1, the image forming apparatus 10 forms a toner image (an example of an image) on a conveying section 17 that conveys the continuous paper P in the direction of arrow A, and on the continuous paper P that is conveyed by the conveying section 17. An image forming section 14 , a fixing device 16 that fixes a toner image onto the continuous paper P, a contact section 90 , and a contact/separation mechanism 99 are provided. Specific configurations of the conveying section 17, the image forming section 14, the fixing device 16, the contact section 90, and the contact/separation mechanism 99 will be described below.

(Conveyor 17)
The continuous paper P transported by the transport unit 17 is a long recording medium having a length in the transport direction. Paper is used as an example of the recording medium. The recording medium is not limited to paper, and may be a film made of a resin material. Therefore, the continuous paper P may be a paper-like (sheet-like) recording medium. Further, as the continuous paper P, for example, the length in the transport direction is set to be equal to or longer than the length that can be collectively sandwiched between the transfer units 50Y to 50K, which will be described later.

The transport unit 17 has an unwinding roll 72 for unwinding the continuous paper P, a winding roll 74 for winding the continuous paper P, and winding rolls 77 and 78 around which the continuous paper P is wound. . The winding roll 74 is rotationally driven by a drive section (not shown). As a result, the continuous paper P is wound by the winding roll 74 and the continuous paper P is unwound by the unwinding roll 72 .

The winding rolls 77 and 78 are wound around the continuous paper P between the unwinding roll 72 and the winding roll 74 . Thus, a transport path for the continuous paper P from the unwinding roll 72 to the winding roll 74 is defined. The winding rolls 77 and 78 rotate following the continuous paper P advancing toward the winding roll 74 when the winding roll 74 winds the continuous paper P. As shown in FIG. In the image forming apparatus 10, the transport section 17 transports the continuous paper P in a substantially horizontal direction. In other words, the conveying direction of the conveying unit 17 can also be said to be the lateral direction or the lateral direction.

(Fixing device 16)
The fixing device 16 has a heating roll 62 that heats the continuous paper P and a pressure roll 64 that presses the continuous paper P. As shown in FIG. In the fixing device 16, the continuous paper P is sandwiched between the heating roll 62 and the pressure roll 64, and the continuous paper P is heated and pressed to fix the toner image on the continuous paper P to the continuous paper P.

(Image forming unit 14)
The image forming section 14 has toner image forming sections 14Y, 14M, 14C, and 14K that form toner images of respective colors of yellow (Y), magenta (M), cyan (C), and black (K). The toner image forming units 14Y, 14M, 14C, and 14K (hereinafter referred to as 14Y to 14K) are arranged in this order from upstream to downstream in the continuous paper P transport direction.

Each of the toner image forming sections 14Y to 14K includes an image forming unit 18, a transfer unit 50 as an example of a transfer section, and a contact/separation mechanism 56. As shown in FIG. Note that each of the toner image forming units 14Y to 14K has the same configuration except for the toner used. In FIG. 1, the image forming unit 18, the transfer unit 50, the contact/separation mechanism 56, and the transfer units 50Y to 50K are indicated by Y, M, C, and K depending on the color of the toner used. attached.

(Image forming unit 18)
Each image forming unit 18Y, 18M, 18C, 18K (hereinafter referred to as 18Y to 18K) is a unit that forms a toner image using a liquid developer. Specifically, as shown in FIG. 1, each of the image forming units 18Y to 18K includes a rotating photosensitive drum 22, a charging device 24 that charges the photosensitive drum 22, and an exposure light to the photosensitive drum 22. It has an exposure device 26 that irradiates to form an electrostatic latent image, and a developing device 40 that develops the electrostatic latent image on the photosensitive drum 22 to form a toner image.

Note that the image forming units 18Y to 18K are configured in the same manner except for the toner used, so the reference numerals of the image forming units 18M, 18C, and 18K are omitted in FIG.

The developing device 40 has a developing roll 42 (developer). The developing roll 42 is a roll that develops the electrostatic latent image formed on the photosensitive drum 22 with a liquid developer in which toner (particles) are dispersed in a carrier liquid. Specifically, the developing roll 42 is supplied with the liquid developer from a supply roll (not shown) immersed in the liquid developer, and retains the liquid developer on the outer peripheral surface. The developing roll 42 is rotationally driven in the opposite direction (counterclockwise direction in FIG. 1) to the rotating direction (clockwise direction in FIG. 1) of the photosensitive drum 22 at substantially the same speed as the photosensitive drum 22 .

The liquid developer held on the developing roll 42 is supplied from the developing roll 42 to the photosensitive drum 22 . The liquid developer develops the electrostatic latent image on the photosensitive drum 22 to form a toner image.

(transcription unit 50)
The transfer units 50Y, 50M, 50C, and 50K (hereinafter referred to as 50Y to 50K) are an example of a plurality of transfer units that sandwich the conveyed continuous paper and sequentially transfer images onto the continuous paper. Specifically, the transfer units 50Y to 50K are units that transfer the toner images formed by the image forming units 18Y to 18K onto the continuous paper P while holding the continuous paper P transported by the transport unit 17 therebetween. More specifically, each transfer unit 50Y to 50K has a transfer roll 52 and an opposing roll 54 (backup roll).

Each of the transfer rolls 52Y, 52M, 52C, and 52K (hereinafter referred to as 52Y to 52K) is configured such that a portion of the outer peripheral surface comes into contact with a portion of the outer peripheral surface of each photosensitive drum 22 and rotates. A transfer voltage is applied between each of the transfer rolls 52Y to 52K and each of the photosensitive drums 22 by applying means (not shown). As a result, a transfer electric field is formed between each of the transfer rolls 52Y to 52K and each of the photosensitive drums 22, and an electrostatic force acts on the toner image formed on each of the photosensitive drums 22, causing the toner image to be transferred. It is transferred to each of transfer rolls 52Y to 52K. Each of the transfer rolls 52Y to 52K holds the transferred toner image on its outer peripheral surface. That is, each of the transfer rolls 52Y to 52K is an example of a holder that holds an image.

The opposed rolls 54Y, 54M, 54C, and 54K (hereinafter referred to as 54Y to 54K) are arranged on the opposite side of the continuous paper P being transported by the transport section 17 from the transfer rolls 52Y to 52K. In other words, the facing rolls 54Y to 54K face the transfer rolls 52Y to 52K with the continuous paper P therebetween. That is, each of the facing rolls 54Y to 54K is an example of a facing body facing each of the transfer rolls 52Y to 52K with the continuous paper P therebetween. A transfer voltage is applied by applying means (not shown) between the transfer rolls 52Y to 52K and the opposing rolls 54Y to 54K.

As a result, a transfer electric field is formed between each of the transfer rolls 52Y to 52K and each of the opposing rolls 54Y to 54K, and an electrostatic force acts on the toner image held by each of the transfer rolls 52Y to 52K. The image is transferred to the continuous paper P at the transfer position.

(Contact and separation mechanism 56)
Each of the contact/separation mechanisms 56Y, 56M, 56C, and 56K (hereinafter referred to as 56Y to 56K) is a mechanism for bringing the opposing rolls 54Y to 54K into contact with or away from the continuous paper P. As shown in FIG. Note that "contact and separation" means contact and separation.

In other words, the contact/separation mechanisms 56Y-56K are mechanisms for moving the opposing rolls 54Y-54K between the contact position (the position shown in FIG. 1) and the separation position (the position shown in FIG. 2) with respect to the continuous paper P. . Then, the facing rolls 54Y to 54K press the continuous paper P against the transfer rolls 52Y to 52K at the contact positions (positions shown in FIG. 1). In other words, the opposing rolls 54Y to 54K push the continuous paper P toward the transfer rolls 52Y to 52K at the contact positions to bring the continuous paper P into contact with the transfer rolls 52Y to 52K.

Each of the opposing rolls 54Y to 54K is separated from the continuous paper P at the separation position (the position shown in FIG. 2). When the facing rolls 54Y to 54K are positioned at the separated positions, the continuous paper P is separated from the transfer rolls 52Y to 52K because the pressing force of the facing rolls 54Y to 54K does not act on the continuous paper P. That is, the separated position is a position where the pressing force of the facing rolls 54Y to 54K does not act on the continuous paper P, and is a position where the facing rolls 54Y to 54K and the transfer rolls 52Y to 52K are separated from the continuous paper P.

As described above, each contact/separation mechanism 56Y-56K functions as a mechanism for contacting/separating both the transfer rolls 52Y-52K and the opposing rolls 54Y-54K from the continuous paper P. FIG. In other words, the contact/separation mechanisms 56Y to 56K control the contact state in which the transfer rolls 52Y to 52K and the opposing rolls 54Y to 54K contact the continuous paper P, and the transfer rolls 52Y to 52K and the opposing rolls 54Y to 54K. is separated from the continuous paper P. The contact state can also be said to be a state in which the continuous paper P is sandwiched between the transfer rolls 52Y to 52K and the opposing rolls 54Y to 54K.

The transfer rolls 52Y to 52K are configured so as not to be displaced (not changed in position). The above-described transfer operation in which the toner images held on the transfer rolls 52Y to 52K are transferred to the continuous paper P is a contact state in which the transfer rolls 52Y to 52K and the opposing rolls 54Y to 54K are in contact with the continuous paper P. performed in

Here, in this embodiment, for example, when the continuous paper P is placed on the transport path, the contact/separation mechanisms 56Y to 56K separate the transfer rolls 52Y to 52K and the opposing rolls 54Y to 54K. Then, for example, the operator places the continuous paper P on the transport path while the transfer rolls 52Y to 52K and the opposing rolls 54Y to 54K are separated from each other.

Each of the contact/separation mechanisms 56Y to 56K, for example, swings a support member that rotatably supports each of the facing rolls 54Y to 54K by a cam or the like, thereby bringing each of the facing rolls 54Y to 54K into contact with or separating from the continuous paper P. A mechanism is used to allow

The mechanism for bringing the transfer rolls 52Y to 52K and the opposing rolls 54Y to 54K into contact with and separating from each other may be a mechanism to bring the transfer rolls 52Y to 52K and the opposing rolls 54Y to 54K into contact with and separate from each other. Alternatively, a mechanism may be used in which both the transfer rolls 52Y to 52K and the opposing rolls 54Y to 54K are brought into contact with and separated from each other by bringing the transfer rolls 52Y to 52K into contact with each other.

(4 color mode and single color mode)
In this embodiment, the image forming apparatus 10 has a four-color mode (multi-color mode) and a single-color mode using black (K).

In the four-color mode, the transfer rolls 52Y to 52K and the opposing rolls 54Y to 54K are brought into contact with the continuous paper P as shown in FIG. Therefore, for example, in a separated state in which the transfer rolls 52Y to 52K and the opposing rolls 54Y to 54K are separated from the continuous paper P, when the mode is shifted to the four-color mode, the transfer rolls 52Y to 52K and the opposing rolls 52Y to 52K are moved by the contact/separation mechanisms 56Y to 56K. The rolls 54Y to 54K are switched to the contact state where the continuous paper P is in contact.

In the four-color mode, the toner images held on the transfer rolls 52Y to 52K are sequentially transferred onto the continuous paper P by application of transfer voltages between the transfer rolls 52Y to 52K and the opposing rolls 54Y to 54K. be done. Specifically, the toner images held by the transfer rolls 52Y to 52K are superimposed and transferred onto the continuous paper P in the order of yellow (Y), magenta (M), cyan (C), and black (K). be.

In the 4-color mode, since the continuous paper P is pressed against the transfer rolls 52Y-52K by the opposing rolls 54Y-54K, the continuous paper P is transported along a route (hereinafter referred to as a 4-color route) in contact with the transfer rolls 52Y-52K. be.

In the monochrome mode, as shown in FIG. 2, the transfer rolls 52Y, 52M, 52C and the opposing rolls 54Y, 54M, 54C are separated from the continuous paper P, and the transfer roll 52K and the opposing roll 54K are separated from the continuous paper. A contact state is brought into contact with P.

Therefore, in the monochrome mode, in the transfer units 50Y, 50M, and 50C arranged on the upstream side of the contact portion 90, including the transfer unit 50C arranged immediately upstream of the contact portion 90, the transfer roll 52 and the counter roll 54C are continuous. It is in a separated state in which it is separated from the paper P.

Note that "arranged immediately upstream of the contact portion 90" means being arranged at a position closest to the contact portion 90 on the upstream side of the contact portion 90 (on the upstream side in the conveying direction of the continuous paper P). Say.

In the monochrome mode, the black (K) toner image held on the transfer roll 52K is transferred to the continuous paper P by application of a transfer voltage between the transfer roll 52K and the opposing roll 54K.

In the monochrome mode, the continuous paper P is conveyed along a path (hereinafter referred to as a monochrome path) separated from the transfer rolls 52Y, 52M, and 52C between the winding roll 77 and the transfer unit 50K. Therefore, the single-color path is formed closer to the facing rolls 54Y, 54M, and 54C (lower side in FIG. 2) than the four-color path.

(Contact portion 90)
The contact portion 90 is an example of a contact portion that is arranged between a plurality of transfer portions and contacts the continuous paper. The contact portion 90 is also an example of a constraint portion that is arranged between a plurality of transfer portions and constrains the variation in the thickness direction of the continuous paper.

Specifically, as shown in FIG. 2, the contact portion 90 is arranged between the transfer unit 50C and the transfer unit 50K. This contact portion 90 has a first roll 91 and a second roll 92 .

The first roll 91 is an example of a first contact member that contacts the image surface of the continuous paper. An "image side" is the side to which an image is transferred. Note that the image plane faces upward. In other words, the upper surface of the continuous paper P is the image surface.

The first roll 91 is a roll that rotates around an axis along the width direction of the continuous paper P. As shown in FIG. Specifically, the first roll 91 is a roll that rotates counterclockwise in FIG. 2 following the continuous paper P being transported. The width direction of the continuous paper P is a direction that intersects (specifically, is perpendicular to) the conveying direction of the continuous paper P and the thickness direction of the continuous paper P.

As will be described later, the first roll 91 has a contact position (position shown in FIG. 2) at which it contacts the continuous paper P conveyed along the single-color path, and a separation position (position shown in FIG. 2) at which it is separated from the continuous paper P. 3), and can be moved by the contact/separation mechanism 99. As shown in FIG. That is, in the present embodiment, the first roll 91 is driven to rotate in contact with the continuous paper P conveyed through the single-color path when positioned at the contact position.

In addition, the first roll 91 is separated from the continuous paper P conveyed on the single-color path and the continuous paper P conveyed on the four-color path in the state of being positioned at the separated position.

In addition, the length of the first roll 91 in the axial direction is equal to or greater than the length of the continuous paper P in the width direction. The first roll 91 contacts the continuous paper P from one end to the other end in the width direction.

The second roll 92 is an example of a second contact member that contacts the non-image side of the continuous paper. "Non-image side" is the side opposite the image side. Note that the non-image surface faces downward. In other words, the lower surface of the continuous paper P is the non-image surface.

The second roll 92 is a roll that rotates around an axis along the width direction of the continuous paper P. As shown in FIG. Specifically, the second roll 92 is a roll that rotates clockwise in FIG. 2 following the continuous paper P being transported.

The second roll 92 is arranged at a position in contact with the continuous paper P that is transported along the single-color path. That is, in the present embodiment, in the monochrome mode, the second roll 92 is driven to rotate in contact with the continuous paper P conveyed through the monochrome path.

As shown in FIG. 1, the second roll 92 is not in contact with the continuous paper P that is conveyed through the four-color path in the four-color mode. That is, the arrangement position of the second roll 92 is a position separated from the continuous paper P conveyed along the four-color path.

In addition, the length of the second roll 92 in the axial direction is equal to or greater than the length of the continuous paper P in the width direction. Then, the second roll 92 is in contact with the continuous paper P from one end portion to the other end portion in the width direction.

(Contact and separation mechanism 99)
The contact/separation mechanism 99 is a mechanism that brings the first roll 91 into contact with or separates from the continuous paper P. As shown in FIG. Specifically, the contact/separation mechanism 99 is a mechanism that brings the first roll 91 into contact with or separates from the continuous paper P that is conveyed along the single-color path.

In other words, the contact/separation mechanism 99 is a mechanism for moving the first roll 91 between the contact position (the position shown in FIG. 2) and the separation position (the position shown in FIG. 3) with respect to the continuous paper P conveyed along the single-color path. is.

Then, the contact/separation mechanism 99 positions the first roll 91 to the separated position in the four-color mode. At the separated position, the first roll 91 is separated from the continuous paper P conveyed along the four-color path.

Further, the contact/separation mechanism 99 positions the first roll 91 to the contact position in the monochrome mode. The first roll 91 contacts the image surface of the continuous paper P conveyed along the monochrome path at the contact position. Therefore, the first roll 91 and the second roll 92 sandwich the continuous paper P conveyed along the single-color path at the contact position.

As the contact/separation mechanism 99, for example, a mechanism that brings the first roll 91 into contact with or separates from the continuous paper P by swinging a support member that rotatably supports the first roll 91 with a cam or the like is used.

It should be noted that the contact/separation mechanism 99 positions the first roll 91 at the separation position also when the continuous paper P is placed on the transport path. Then, in a state in which the first roll 91 is positioned at the separated position, for example, the operator places the continuous paper P on the transport path.

(Action of image forming apparatus 10)
According to the image forming apparatus 10, in the four-color mode, the transfer rolls 52Y to 52K and the opposing rolls 54Y to 54K are brought into contact with the continuous paper P as shown in FIG. That is, the continuous paper P is sandwiched between the transfer rolls 52Y to 52K and the opposing rolls 54Y to 54K.

In the four-color mode, the toner images held on the transfer rolls 52Y to 52K are sequentially transferred onto the continuous paper P by application of transfer voltages between the transfer rolls 52Y to 52K and the opposing rolls 54Y to 54K. be done. Specifically, the toner images held by the transfer rolls 52Y to 52K are superimposed and transferred onto the continuous paper P in the order of yellow (Y), magenta (M), cyan (C), and black (K). be.

In the 4-color mode, the first roll 91 is positioned at the separated position, and is separated from the continuous paper P conveyed through the 4-color path. The second roll 92 is also separated from the continuous paper P conveyed through the four-color path.

Since the first roll 91 is separated from the continuous paper P conveyed on the four-color path, the first roll 91 does not come into contact with the unfixed toner image transferred to the continuous paper P. As a result, the unfixed toner image on the continuous paper P is prevented from being disturbed.

When the image forming apparatus 10 shifts from the four-color mode to the single-color mode, the contact/separation mechanisms 56Y, 56M, and 56C bring the transfer rolls 52Y, 52M, and 52C and the opposing rolls 54Y, 54M, and 54C into contact with the continuous paper P. state to a distant state.

That is, as shown in FIG. 3, in the transfer units 50Y, 50M, and 50C arranged on the upstream side of the contact portion 90, including the transfer unit 50C arranged immediately upstream of the contact portion 90, the transfer roll 52 and the opposing The roll 54</b>C is separated from the continuous paper P.

As a result, the continuous paper P moves from the four-color path to the single-color path, so that the second roll 92 comes into contact with the continuous paper P.

Further, as shown in FIG. 2, the contact/separation mechanism 99 moves the first roll 91 from the separation position to the contact position with respect to the continuous paper P conveyed along the monochromatic path. As a result, the first roll 91 and the second roll 92 sandwich the continuous paper P conveyed along the single-color path from one end to the other end in the width direction. The state in which the continuous paper P is sandwiched between the first roll 91 and the second roll 92 can be said to be a state in which fluctuations in the thickness direction of the continuous paper P are restrained.

Here, in the configuration (first comparative example) in which the first roll 91 and the second roll 92 are separated from the continuous paper P conveyed along the single-color path, fluctuations in the thickness direction of the continuous paper are constrained. However, the continuous paper P may flutter. In the configuration of the first comparative example, the variation in the thickness direction of the continuous paper is not constrained, and in this state, when tension is generated in the continuous paper P along the transport direction, unevenness is formed in the width direction of the continuous paper P. undulation may occur.

When the continuous paper P flutters or undulates, a gap may be formed between the continuous paper P and the transfer roll 52K, and discharge may occur in the gap. If discharge occurs in the gap, transfer defects such as white spots may occur.

On the other hand, in the present embodiment, the first roll 91 and the second roll 92 constrain the fluctuation of the continuous paper P in the thickness direction. is suppressed. Therefore, transfer defects caused by fluttering or waving of the continuous paper P are also suppressed. In particular, since the first roll 91 and the second roll 92 sandwich the continuous paper P conveyed along the monochrome path from one end to the other end in the width direction, the first roll 91 and the second roll 92 Fluttering and rippling of the continuous paper P are suppressed compared to a configuration in which only a portion of the continuous paper P in the width direction is sandwiched.

In the four-color mode, the first roll 91 and the second roll 92 are separated from the continuous paper P. Sandwich Therefore, the continuous paper P is less likely to flutter or wrinkle.

(first modification)
In the present embodiment described above, the first roll 91 is configured to be in contact with the continuous paper P from one end portion to the other end portion in the width direction, but the present invention is not limited to this. As shown in FIG. 4, for example, the first roll 91 may be configured to contact one end portion and the other end portion in the width direction of the continuous paper P outside the image forming area. Specifically, for example, the first roll 91 includes a roll 91A and a roll 91B arranged at one end and the other end in the width direction of the image surface of the continuous paper P. As shown in FIG.

The rolls 91A and 91B contact the non-image areas HL at one end and the other end in the width direction of the image surface of the continuous paper P, respectively.

The continuous paper P has an image forming area GL in the central area in the width direction, and a non-image forming area HL at one end and the other end in the width direction with respect to the image forming area GL. The image forming area GL is an area where the toner images held by the transfer rolls 52Y to 52K are transferred. The non-image forming area HL is an area where the toner images held by the transfer rolls 52Y to 52K are not transferred.

In the configuration of the first modification, each of the rolls 91A and 91B contacts the non-image forming areas HL at one end and the other end of the image surface of the continuous paper P in the width direction. A configuration in which the image surface of the continuous paper P is brought into contact with the 91A and the roll 91B may be employed. With this configuration, it is not necessary to operate the contact/separation mechanism 99 even when the mode is switched between the four-color mode and the single-color mode.

In the configuration of the first modified example, even if the roll 91A and the roll 91B are brought into contact with the image surface of the continuous paper P regardless of the mode, from one end in the width direction of the image surface of the continuous paper P regardless of the mode. Compared to a configuration in which contact is made along the other end portion, the image disturbance on the image surface of the continuous paper P is suppressed while suppressing fluttering and waving of the continuous paper P.

(Second modification)
In the present embodiment described above, the second roll 92 is arranged at a position separated from the continuous paper P that is conveyed through the four-color path in the four-color mode, but the present invention is not limited to this. Since the second roll 92 does not contact the unfixed toner image on the image surface of the continuous paper P, for example, the second roll 92 does not contact the continuous paper P conveyed through the four-color path in the four-color mode. It may be configured to That is, the second roll 92 may be configured to contact the continuous paper P conveyed through the four-color path and the continuous paper P conveyed through the single-color path. In other words, the second roll 92 may be configured to contact the continuous paper P regardless of the mode.

(Third modification)
Although the contact portion 90 has the first roll 91 and the second roll 92 in the present embodiment described above, it is not limited to this. As shown in FIGS. 5 and 6, for example, the contact unit 90 may have only the second roll 92 that contacts the non-image surface of the continuous paper P as a contact member that contacts the continuous paper P. good. According to this configuration, as shown in FIG. 5, in the four-color mode, the second roll 92 is separated from the continuous paper P conveyed along the four-color path.

When the image forming apparatus 10 shifts from the four-color mode to the single-color mode, the contact/separation mechanisms 56Y, 56M, and 56C bring the transfer rolls 52Y, 52M, and 52C and the opposing rolls 54Y, 54M, and 54C into contact with the continuous paper P. state to the separated state (see FIG. 2).

As a result, the continuous paper P moves from the four-color path to the single-color path, so that the second roll 92 contacts the continuous paper P as shown in FIG.

Note that the second roll 92 may be configured to contact the continuous paper P conveyed through the four-color path in the four-color mode, as in the second modification. That is, the second roll 92 may be configured to contact the continuous paper P conveyed through the four-color path and the continuous paper P conveyed through the single-color path. In other words, the second roll 92 may be configured to contact the continuous paper P regardless of the mode.

With this configuration, even if the mode is switched between the four-color mode and the single-color mode, it is not necessary to separate the constituent members of the contact section 90 from the continuous paper P. FIG.

In the configuration of the third modified example, even if the configuration is such that the second roll 92 is brought into contact with the continuous paper P regardless of the mode, the width direction of the continuous paper P from one end to the other end of the image surface of the continuous paper P is increased regardless of the mode. Compared to the contact configuration, the continuous paper P is prevented from fluttering and waving, and the image disturbance on the image surface of the continuous paper P is suppressed.

In particular, since the second roll 92 contacts the continuous paper P from one end to the other end in the width direction, the second roll 92 contacts only a part of the continuous paper P in the width direction. Fluttering and waving of the continuous paper P are suppressed.

(Fourth modification)
In the above-described embodiment, the first roll 91 and the second roll 92 in the contact portion 90 as an example of the restraining portion are configured to contact the continuous paper P, but the present invention is not limited to this. As an example of the restraining section, as shown in FIG. 7, for example, a restraining section 190 that restrains the continuous paper P from varying in the thickness direction without contacting the continuous paper P may be used.

As the restricting unit 190, for example, a blowing mechanism 192 that blows air to the continuous paper P may be used. The air blowing mechanism 192, for example, blows (applies) air to the image surface or non-image surface of the continuous paper P in the direction along the thickness direction of the continuous paper P, thereby blowing air in the thickness direction of the continuous paper P. Mechanisms for constraining fluctuations (for example, air turn bars) are included.

As an example of the restraint unit 190, as shown in FIG. , and is a restraining portion having .

Further, as an example of the restraining section, a restraining section having only an air blowing mechanism for blowing air toward the image surface or the non-image surface of the continuous paper P may be used.

In the configuration of the fourth modification, the continuous paper P may be constrained even in the four-color mode in order to constrain the continuous paper P from changing in the thickness direction without contacting the continuous paper P. FIG.

Further, in the configuration of the fourth modification, even if the configuration is such that the variation in the thickness direction of the continuous paper P is restricted regardless of the mode, the width direction from one end to the other end of the image surface of the continuous paper P in the width direction is changed regardless of the mode. Compared to the configuration in which the continuous paper P is in contact with the continuous paper P, the image disturbance on the image surface of the continuous paper P is suppressed while suppressing fluttering and waving of the continuous paper P.

Note that the blower mechanism 192 may be used in place of one of the first roll 91 and the second roll 92 . That is, as an example of the restraining section, a restraining section having the air blowing mechanism 192 that blows air toward the image surface of the continuous paper P and the second roll 92 may be used. Further, as an example of the restraining section 190 , a restraining section having a blowing mechanism 192 that blows air toward the non-image surface of the continuous paper P and the first roll 91 may be used.

(Fifth Modification)
In the above-described embodiment, the contact portion 90 is arranged between the transfer unit 50C and the transfer unit 50K, but it is not limited to this. For example, as shown in FIG. 8, the contact portion 90 is located between the transfer unit 50C and the transfer unit 50K, between the transfer unit 50Y and the transfer unit 50M, and between the transfer unit 50Y and the transfer unit 50M. may be placed between In addition, a contact portion 90 may be arranged between the winding roll 77 and the transfer unit 50Y.

The contact portion 90 may be arranged either between the transfer unit 50Y and the transfer unit 50M or between the transfer unit 50Y and the transfer unit 50M.

Also, the contact portion 90 is arranged between the transfer unit 50Y and the transfer unit 50M and/or between the transfer unit 50Y and the transfer unit 50M instead of between the transfer unit 50C and the transfer unit 50K. may

Therefore, the contact portion 90 may be arranged on at least one of the transfer units 50Y to 50K.

(Other modifications)
In the image forming apparatus 10, the first roll 91 and the second roll 92 are rotating rolls, but are not limited to this. The contact member may be configured so as not to rotate with respect to the continuous paper P and to slide with respect to the continuous paper P.

In the image forming apparatus 10, the conveying direction of the continuous paper P is substantially horizontal, but the conveying direction is not limited to this. For example, the transport direction of the continuous paper P may be upward or downward.

In the image forming apparatus 10, the image surface of the continuous paper P faces upward, but the present invention is not limited to this. For example, the continuous paper P may have a configuration in which the image surface faces downward. In this configuration, the image forming unit 18 is arranged on the lower surface side of the continuous paper P, and the transfer unit 50 is arranged on the upper surface side of the continuous paper P. As shown in FIG. That is, the image forming unit 18 and the transfer unit 50 in the image forming apparatus 10 are arranged upside down. In the case of a configuration in which the image surface faces downward, for example, the air blowing mechanism 192 in the above-described fourth modification is arranged below the continuous paper P, and the image surface of the continuous paper P is A configuration may be adopted in which air is sent (applied) in a direction along the thickness direction of P to constrain the fluctuation of the continuous paper P in the thickness direction.

Although the image forming apparatus 10 uses the liquid developer, the present invention is not limited to this. The image forming apparatus may be, for example, a dry image forming apparatus using a powdery developer.

In the image forming apparatus 10, the toner image transferred from the photosensitive drum 22 to the transfer roll 52 is transferred to the continuous paper P, but the present invention is not limited to this. A configuration in which the toner image formed on the photosensitive drum 22 is directly transferred onto the continuous paper P may be employed. In this case, the photosensitive drum 22 functions as an example of a holder that holds an image.

The present invention is not limited to the above-described embodiments, and various modifications, changes, and improvements are possible without departing from the scope of the invention. For example, the modifications shown above may be configured by appropriately combining a plurality of them.

10 image forming apparatus 50 transfer unit (an example of a transfer unit)
90 contact part (an example of restraint part)
91 first roll (an example of a first contact member)
92 second roll (an example of a second contact member)
P Continuous paper

Claims (3)

a plurality of transfer units that sandwich the conveyed continuous paper and sequentially transfer images onto the continuous paper;
a restraining unit disposed between the plurality of transfer units and restraining variations in the thickness direction of the continuous paper by coming into contact with the continuous paper;
with
The restraining part is
a first contact member that contacts the image surface of the continuous paper;
a second contact member that contacts the non-image side of the continuous paper;
has
sandwiching the continuous paper between the first contact member and the second contact member;
The first contact member is
In a state in which the transfer unit disposed immediately upstream of the restraint unit is separated from the continuous paper, the transfer unit is in contact with the continuous paper from one end to the other end in a width direction that intersects the conveying direction and the thickness direction,
The continuous paper is separated from the continuous paper in a state in which the transfer unit disposed immediately upstream of the restraining unit sandwiches the continuous paper.
Image forming device. A plurality of the restraint portions are provided,
Each of the plurality of restraining portions is arranged between each of the plurality of transfer portions.
The image forming apparatus according to claim 1. The restraining part is
It is arranged between the transfer section arranged most downstream in the conveying direction and the transfer section arranged immediately upstream of the transfer section among the plurality of transfer sections.
The image forming apparatus according to claim 1.

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