JP7268310B2 - image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

Japanese Unexamined Patent Application Publication No. 2002-100001 discloses an image forming apparatus that includes a conveying belt that conveys a sheet in the vertical direction and a suction roll that attracts the sheet to the conveying belt.

JP 2009-86517 A

Here, when an image is sequentially transferred at the first transfer position and the second transfer position from the two intermediate transfer belts onto the recording medium conveyed by the conveyance belt, the image is recorded at the time of transfer at the first transfer position. Media charging can affect the transferability of the image at the second transfer location.

An object of the present invention is to suppress the influence on the transferability of an image at the second transfer position compared to a configuration in which the recording medium is conveyed to the second transfer position while being charged at the first transfer position. do.

In a first aspect, a conveying belt is arranged along a conveying path and contacts one side of a recording medium to convey the recording medium, and an image is transferred onto the recording medium conveyed by the conveying belt at a first transfer position. A first intermediate transfer belt to which the image is transferred, and a second intermediate transfer belt to which the image is transferred at a second transfer position downstream of the first transfer position in the conveying direction with respect to the recording medium conveyed by the conveying belt. and a neutralizing means disposed between the first transfer position and the second transfer position for neutralizing the recording medium charged at the first transfer position.

In the second aspect, the conveying belt is formed in an annular shape, and conveys the recording medium with its outer peripheral surface in contact with one side of the recording medium; The recording medium is neutralized through the belt.

In the third aspect, the static eliminating means is a driven roll that contacts the inner peripheral surface of the transport belt and rotates following the transport belt.

In a fourth aspect, the conveying belt conveys the recording medium from the lower side to the upper side in the direction of gravity, and the first intermediate transfer belt and the second intermediate transfer belt overlap vertically in the direction of gravity. .

In the fifth aspect, the charge removing means imparts to the recording medium a charge having a polarity opposite to that of the recording medium charged at the first transfer position by applying a voltage.

A sixth aspect comprises reception means for receiving information on the recording medium, and changes the voltage applied to the static elimination means based on the information received by the reception means.

According to the configuration of the first aspect, compared with the configuration in which the recording medium is conveyed to the second transfer position while being charged at the first transfer position, the effect on the transferability of the image at the second transfer position is suppressed. can.

According to the configuration of the second aspect, the charge removing means can charge the recording medium conveyed by the conveying belt in a non-contact manner.

According to the configuration of the third mode, the frictional resistance with the conveying belt can be reduced compared to the configuration in which the neutralizing means slides relative to the conveying belt.

According to the configuration of the fourth aspect, compared to the configuration in which the conveying belt conveys the recording medium in the horizontal direction and the entire first intermediate transfer belt is horizontally displaced from the second intermediate transfer belt, the image It is possible to reduce the size of the forming apparatus in the horizontal direction while suppressing the influence on the transferability of the image at the second transfer position.

According to the configuration of the fifth mode, the static elimination capability of the static elimination means can be increased compared to a configuration in which the static elimination means is grounded to the reference potential (ground) and functions as a ground that only releases the charge of the recording medium.

According to the configuration of the sixth aspect, compared to the configuration in which the voltage applied to the charge removing device is constant, the charge removing ability of the charge removing device can be changed according to the recording medium.

1 is a schematic diagram showing the configuration of an image forming apparatus according to an embodiment; FIG. FIG. 2 is a schematic diagram showing configurations of a conveying belt, a first image forming unit, and a second image forming unit according to the exemplary embodiment; 2 is a perspective view showing the configuration of a first image forming unit (second image forming unit) according to the exemplary embodiment; FIG. FIG. 4 is a schematic diagram showing a control system that controls the operation of the static elimination roll according to the embodiment;

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

An arrow UP shown in the drawing indicates the upper side (vertically upward) of the apparatus, and an arrow DO indicates the lower side (vertically downward) of the apparatus. An arrow LH shown in the drawing indicates the left side of the device, and an arrow RH indicates the right side of the device. An arrow FR shown in the drawing indicates the front of the device, and an arrow RR indicates the rear of the device. These directions are defined for convenience of explanation, and the configuration of the apparatus is not limited to these directions.

Also, the directions along the top and bottom of the device may be referred to as the vertical direction of the device. The longitudinal direction of the device is also the direction of gravity. Also, the directions along the left and right sides of the device may be referred to as the left-right direction of the device. The lateral direction of the device is also the width direction (horizontal direction) of the device. Also, the directions along the front and rear of the device may be referred to as the front-rear direction of the device. The front-rear direction of the device is also the depth direction (horizontal direction) of the device. Note that the word “device” may be omitted in each direction of the device. That is, for example, "above the device" may be simply referred to as "above".

In addition, the symbol in which "x" is described in "o" in the figure means an arrow pointing from the front to the back of the paper surface. In addition, the symbol "·" written in the "o" in the drawing means an arrow pointing from the back to the front of the paper surface.

<Image forming apparatus 10>
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.

An image forming apparatus 10 shown in FIG. 1 is an example of an image forming apparatus that forms an image on a recording medium. Specifically, the image forming apparatus 10 is an electrophotographic image forming apparatus that forms a toner image (an example of an image) on the recording medium P. As shown in FIG. More specifically, as shown in FIG. 1, the image forming apparatus 10 includes an apparatus main body 11, an accommodating section 12, a discharge section 18, a conveying section 13, an image forming section 14, and a fixing device 19. , and static elimination rolls 81 and 82 . Each section of the image forming apparatus 10 (apparatus main body 11, storage section 12, discharge section 18, conveying section 13, image forming section 14, fixing device 19, and neutralization rolls 81 and 82) will be described below.

(Apparatus main body 11, storage section 12 and discharge section 18)
The apparatus main body 11 shown in FIG. 1 has a function of housing each component inside. The apparatus main body 11 is configured by, for example, a box-shaped housing.

The accommodation unit 12 has a function of accommodating a recording medium P such as paper. The accommodating portion 12 is provided in the lower part inside the device main body 11 as shown in FIG. In the present embodiment, the recording medium P is accommodated in the accommodation portion 12 by being stacked on the accommodation portion 12 .

The ejection section 18 has a function of ejecting the recording medium P on which the toner image is formed. The discharge section 18 is provided on the upper portion of the apparatus main body 11 as shown in FIG. In this embodiment, the recording medium P ejected toward the ejection section 18 is stacked on the ejection section 18 .

(Conveyor 13)
The transport unit 13 shown in FIG. 1 has a function of transporting the recording medium P. As shown in FIG. Specifically, the transport unit 13 has a function of transporting the recording medium P through a transport path 38 extending in the vertical direction. More specifically, the transport section 13 has a function of transporting the recording medium P upward from the storage section 12 to the discharge section 18 along the transport path 38 .

Further explaining, as shown in FIG. 1 , the transport section 13 has a delivery roll 32 , a plurality of transport rolls 34 , a transport belt 20 , and a discharge roll 36 . The delivery roll 32 is a roll that delivers the recording medium P accommodated in the accommodation section 12 . A plurality of transport rolls 34 are rolls that transport the recording medium P delivered by the delivery roll 32 toward the transport belt 20 .

The transport belt 20 is arranged along a transport path 38 extending in the longitudinal direction. The transport belt 20 has a function of contacting one side of the recording medium P and transporting the recording medium P. As shown in FIG.

Specifically, the transport belt 20 is belt-shaped and has a width in the front-rear direction, and is formed in an annular shape. More specifically, the conveyor belt 20 is, for example, formed in an endless shape with no ends.

More specifically, the transport belt 20 is wound around a pair of rolls 22 . Specifically, the conveying belt 20 is wound around a pair of rolls 22 spaced vertically (in the vertical direction) while being tensioned. More specifically, the conveying belt 20 has a pair of rolls 22, i.e., a driven roll 22A arranged below inside the apparatus main body 11 and a driving roll 22B arranged above the driven roll 22A. It is wrapped around in a state where it is given. In this embodiment, the drive roll 22B is rotated in one direction (arrow A direction) by a drive source (not shown), so that the transport belt 20 is rotated in one direction (arrow B direction).

More specifically, the transport belt 20 has a function of transporting the recording medium P with its outer peripheral surface in contact with the non-image surface of the recording medium P. As shown in FIG. Specifically, the conveying belt 20 contacts the non-image surface of the recording medium P at the contact surface 20A facing leftward (first intermediate transfer belt 71 and second intermediate transfer belt 72, which will be described later) on the outer peripheral surface. The recording medium P is conveyed. More specifically, the transport belt 20 transports the recording medium P while electrostatically attracting the non-image surface of the recording medium P to the contact surface 20A. Note that the contact surface 20A is specifically a surface extending linearly along the vertical direction. The non-image surface of the recording medium P is the surface opposite to the image surface on which the toner image is formed. Thus, in this embodiment, the transport belt 20 is configured to transport the recording medium P from the lower side to the upper side in the direction of gravity.

The discharge roll 36 is a roll that discharges the recording medium P that has passed through the fixing device 19 after being transported by the transport belt 20 to the discharge section 18 .

As described above, the transport unit 13 transports the recording medium P upward. Therefore, in the transport unit 13, the upward direction is the transport direction. In addition, in the conveying unit 13, the lower side is the downstream side in the conveying direction, and the upper side is the downstream side in the conveying direction.

(Image forming unit 14)
The image forming section 14 shown in FIG. 1 has a function of forming a toner image (an example of an image) on the recording medium P. As shown in FIG. Specifically, as shown in FIG. 1 , the image forming section 14 has a first image forming unit 41 , a second image forming unit 42 and two secondary transfer rolls 48 .

The configurations of the first image forming unit 41, the second image forming unit 42, and the two secondary transfer rolls 47 and 48 will be described below.

[First image forming unit 41]
The first image forming unit 41 is provided in the lower part inside the apparatus main body 11, as shown in FIG. Specifically, the first image forming unit 41 is arranged on the upper side of the storage section 12 and on the left side of the conveying belt 20 .

2 and 3, the first image forming unit 41 includes a unit body 60, four toner image forming sections 50, four primary transfer rolls 75, a first intermediate transfer belt 71, It has a motor 68 , a power supply board 62 , a control board 64 and a high voltage power supply board 66 .

Specifically, the first image forming unit 41 has four toner image forming units 50, which are yellow (Y), magenta (M), cyan (C), and white (W). has 50. (Y), (M), (C), and (W) shown in FIG. 2 indicate components corresponding to the respective colors. Since the toner image forming units 50 for each color are configured in the same manner except for the toner used, each portion of the toner image forming unit 50 (Y) in FIG. is attached. Each part of the first image forming unit 41 (unit main body 60, four toner image forming parts 50, four primary transfer rolls 75, first intermediate transfer belt 71, motor 68, power supply board 62, control board 64, and high voltage The power supply board 66) will be described.

[Unit body 60]
A unit main body 60 shown in FIG. 3 functions as a support that supports each part of the first image forming unit 41 . The unit main body 60 is configured by a frame formed of sheet metal, for example. The unit body 60 has, for example, an upper wall 60U, a front wall 60F, a rear wall 60R and a left wall 60L (side walls), as shown in FIG. In FIG. 2, the front wall 60F and the left wall 60L (side walls) are omitted.

[Toner image forming unit 50]
As shown in FIG. 2, the toner image forming section 50 for each color has a photoreceptor drum 52 (photoreceptor) that rotates in one direction (direction of arrow E). Furthermore, the toner image forming section 50 for each color has a charging device 53 , an exposure device 54 , a developing device 56 and a removing device 58 .

In the toner image forming section 50 for each color, the charging device 53 charges the photosensitive drum 52 . Further, the exposure device 54 exposes the photosensitive drum 52 charged by the charging device 53 to form an electrostatic latent image on the photosensitive drum 52 . Further, the developing device 56 develops the electrostatic latent image formed on the photosensitive drum 52 by the exposure device 54 to form a toner image. The removing device 58 is composed of a blade that removes toner remaining on the photosensitive drum 52 after the toner image is transferred to the first intermediate transfer belt 71, which will be described later.

[Primary transfer roll 75]
The four primary transfer rolls 75 are arranged inside (inner peripheral side) of the first intermediate transfer belt 71, as shown in FIG. Specifically, each of the four primary transfer rolls 75 is arranged to face the photosensitive drum 52 of each color with the first intermediate transfer belt 71 interposed therebetween.

Each primary transfer roll 75 has a function of transferring the toner image of each color photoreceptor drum 52 onto the first intermediate transfer belt 71 at a primary transfer position T1 between the photoreceptor drum 52 and the primary transfer roll 75. ing. In this embodiment, a primary transfer electric field is applied between the primary transfer roll 75 and the photoreceptor drum 52, so that the toner image formed on the photoreceptor drum 52 is transferred at the primary transfer position T1 to the first intermediate transfer position. It is transferred to the belt 71 . As a result, the toner images on the photosensitive drums 52 of the respective colors are primarily transferred onto the first intermediate transfer belt 71 .

[First intermediate transfer belt 71]
The first intermediate transfer belt 71 has a function of conveying the toner images transferred from the respective color photosensitive drums 52 of the first image forming unit 41 to a first secondary transfer position T21, which will be described later. Specifically, the first intermediate transfer belt 71 is configured as follows.

The first intermediate transfer belt 71 is belt-shaped and has a width in the front-rear direction, and is formed in an annular shape. Specifically, the first intermediate transfer belt 71 is formed, for example, in an endless shape without edges.

Further explaining, the first intermediate transfer belt 71 is wound around a pair of rolls 74 . Specifically, the first intermediate transfer belt 71 is wound around a pair of rolls 74 spaced apart in the left-right direction while being tensioned. More specifically, the first intermediate transfer belt 71 includes, as a pair of rolls 74, a driving roll 74A disposed on the right side (conveyor belt 20 side) inside the apparatus main body 11 and a driving roll 74A on the left side of the driving roll 74A (driving roll 74A). A driven roll 74B disposed on the side opposite to the conveying belt 20 with respect to the roll 74A is wound under tension. In the present embodiment, the drive roll 74A rotates in one direction (direction of arrow C) by the motor 68, so that the first intermediate transfer belt 71 rotates in one direction (direction of arrow D). The drive roll 74A functions as a counter roll (backup roll) for the secondary transfer roll 48. As shown in FIG.

The first intermediate transfer belt 71 has a contact area 71N (nip area) in contact with the transport belt 20 at the portion wound around the drive roll 74A. This contact area 71N serves as a first secondary transfer position T21 where the toner image on the first intermediate transfer belt 71 is transferred onto the recording medium P. As shown in FIG. Further, the first intermediate transfer belt 71 conveys the recording medium P while sandwiching it with the conveying belt 20 in the contact area 71N. The first secondary transfer position T21 is an example of a first transfer position.

The first image forming unit 41 has a removing section 78 that removes toner remaining on the first intermediate transfer belt 71 after the toner image is transferred onto the recording medium P. As shown in FIG. The removal unit 78 is formed of a blade that is arranged above the first intermediate transfer belt 71 and between the high-voltage power supply board 66 and the transport belt 20 . A facing roll 79 is provided below the removing section 78 so as to face the removing section 78 with the first intermediate transfer belt 71 interposed therebetween.

[Motor 68]
The motor 68 is provided on the rear wall 60R of the unit body 60 in the first image forming unit 41, as shown in FIG. This motor 68 functions as a driving source for driving the driving portion of the first image forming unit 41 . Specifically, the motor 68 rotates, for example, the photosensitive drum 52, the developing roller 56A of the developing device 56, the driving roller 74A around which the first intermediate transfer belt 71 is wound, etc. via a gear train (not shown). drive. Furthermore, the driving force of the motor 68 is transmitted to, for example, the delivery roll 32 and the plurality of transport rolls 34 of the transport section 13, and the delivery roll 32 and the plurality of transport rolls 34 are rotationally driven.

[Power supply board 62, control board 64 and high voltage power supply board 66]
The power supply board 62, the control board 64, and the high-voltage power supply board 66 are provided above the unit main body 60, as shown in FIGS.

The power supply board 62 is supplied with power from an external power source (not shown) of the image forming apparatus 10 via electric wires (not shown), and has a function of supplying power of a predetermined voltage to the motor 68 and the like. are doing. The power board 62 has electronic components 62A on its upper surface.

The control board 64 has a function of controlling the driving of each section of the first image forming unit 41 . The control board 64 has a recording unit including a ROM (ROM) in which a program is recorded, a storage, and the like, and a processor that operates according to the program. The control board 64 has electronic components 62A on its upper surface.

As shown in FIG. 4, the control board 64 is connected with a user interface 17 (hereinafter referred to as UI 17) as an operation unit. The UI 17 is composed of, for example, a liquid crystal display with a touch panel. Operation buttons (virtual buttons) and information to be notified to the operator (user) are displayed on the screen.

By operating the operation buttons through the UI 17, the operator designates the image forming conditions including the selection of the type of the recording medium P. FIG. The operation unit may be, for example, a personal computer (PC) connected to the image forming apparatus 10 via a network. good.

The high-voltage power supply board 66 is supplied with electric power from a power supply (not shown) external to the image forming apparatus 10 via electric wires (not shown), and supplies power higher than the voltage of the power supply board 62 to the charging device 53 . , the developing device 56, the four primary transfer rolls 75, the secondary transfer rolls 47 and 48, the charge removing rolls 81 and 82, and the like. The high-voltage power supply board 66 has electronic components 66A on its lower surface. The high-voltage power supply board 66 may be configured to be supplied with power from the power supply board 62 .

[Second image forming unit 42]
The second image forming unit 42 is provided in the upper part inside the apparatus main body 11 . Specifically, the second image forming unit 42 is arranged above the first image forming unit 41 and on the left side of the conveying belt 20 . Also, the second image forming unit 42 is arranged to overlap the first image forming unit 41 in the vertical direction.

In this embodiment, the second image forming unit 42 is configured similarly to the first image forming unit 41 . Specifically, the second image forming unit 42 includes a unit body 60, four toner image forming sections 50, four primary transfer rolls 75, a second intermediate transfer belt 72, a motor 68, and a power board 62. , a control board 64 and a high-voltage power supply board 66 .

The second image forming unit 42 has four toner image forming units 50 of four colors: transparent (T), silver (S), gold (G), and black (K). ing. (T), (S), (G), and (K) shown in FIG. 2 indicate components corresponding to the respective colors. Further, since the toner image forming units 50 of each color are configured in the same manner except for the toner used, each portion of the toner image forming unit 50 (T) in FIG. is attached. Further, since the toner image forming section 50 of the second image forming unit 42 is configured in the same manner as the toner image forming section 50 of the first image forming unit 41, description thereof will be omitted.

In addition, each of the unit body 60, the four primary transfer rolls 75, the power board 62, the control board 64, and the high-voltage power board 66 in the second image forming unit 42 is the unit body 60 in the first image forming unit 41, the four Since it is configured in the same manner as the primary transfer roll 75, the power supply board 62, the control board 64, and the high voltage power supply board 66, the description thereof will be omitted.

The motor 68 in the second image forming unit 42 rotates, for example, the photosensitive drum 52, the developing roll 56A of the developing device 56, the drive roll 74A around which the first intermediate transfer belt 71 is wound, etc., through a gear train (not shown). drive through. Furthermore, the driving force of the motor 68 is transmitted to, for example, the driving roll 22B of the conveying belt 20 and the heating roll 92 of the fixing device 19, which will be described later, so that the driving roll 22B and the heating roll 92 are rotationally driven. In each part of the second image forming unit 42, parts having the same functions as those of the first image forming unit 41 are denoted by the same reference numerals as appropriate.

[Second intermediate transfer bell and 72]
The second intermediate transfer belt 72 is configured similarly to the first intermediate transfer belt 71 of the first image forming unit 41 . The second intermediate transfer belt 72 has a function of conveying the toner images transferred from the respective color photosensitive drums 52 of the second image forming unit 42 to the second secondary transfer position T22.

Specifically, the second intermediate transfer belt 72 has a contact area 72N (nip area) that contacts the conveyor belt 20 at the portion wound around the drive roll 74A. This contact area 72N serves as a second secondary transfer position T22 where the toner image on the second intermediate transfer belt 72 is transferred onto the recording medium P. As shown in FIG. The second secondary transfer position T22 is an example of the second transfer position.

Further, the second intermediate transfer belt 72 has a function of sandwiching the recording medium P sandwiched between the first intermediate transfer belt 71 and the transport belt 20 with the transport belt 20 in the contact area 72N. In other words, the second intermediate transfer belt 72 has the function of sandwiching the recording medium P with the conveying belt 20 at the same time as the first intermediate transfer belt 71 .

More specifically, the second intermediate transfer belt 72 and the first intermediate transfer belt 71 overlap vertically in the direction of gravity. Specifically, the second intermediate transfer belt 72 is arranged above the first intermediate transfer belt 71 so as to overlap the first intermediate transfer belt 71 in the direction of gravity.

[Secondary transfer rolls 47 and 48]
Each of the two secondary transfer rolls 47 and 48 is arranged inside (inner peripheral side) of the conveying belt 20 . Specifically, each of the two secondary transfer rolls 47 and 48 is arranged to face each of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 via the transport belt 20 . More specifically, the secondary transfer roll 47 moves the transport belt 20 and the first intermediate transfer belt 71 to the driving roll 74A of the first image forming unit 41 in the contact area 71N (first secondary transfer position T21). sandwiched between Further, the secondary transfer roll 48 sandwiches the transport belt 20 and the second intermediate transfer belt 72 with the drive roll 74A of the second image forming unit 42 in the contact area 72N (second secondary transfer position T22). I'm in.

Each of the two secondary transfer rolls 47 and 48 has a function of transferring the toner images transferred to the first intermediate transfer belt 71 and the second intermediate transfer belt 72 to the recording medium P, respectively. In the present embodiment, a secondary transfer electric field is applied between each of the secondary transfer rolls 47 and 48 and each drive roll 74A, so that each of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is are secondarily transferred onto the recording medium P at each of the first secondary transfer position T21 and the second secondary transfer position T22. In this embodiment, the applied voltage applied to the secondary transfer roll 48 is a negative transfer voltage.

(Fixing device 19)
The fixing device 19 shown in FIG. 1 functions as fixing means for fixing the image transferred onto the recording medium. Specifically, the fixing device 19 is a device that fixes the toner image transferred onto the recording medium P by the secondary transfer roll 48 onto the recording medium P. As shown in FIG. More specifically, as shown in FIG. 1, the fixing device 19 has a heating roll 92 as a heating member and a pressure roll 94 as a pressure member. In the fixing device 19, the recording medium P is heated and pressed while the recording medium P is conveyed by the heating roll 92 and the pressure roll 94, so that the toner image formed on the recording medium P is transferred to the recording medium P. settle in.

(static elimination rolls 81 and 82)
The neutralizing rolls 81 and 82 shown in FIG. 2 are an example of neutralizing means for neutralizing the recording medium P charged at the first secondary transfer position T21. The neutralization rolls 81 and 82 are arranged between the first secondary transfer position T21 and the second secondary transfer position T22. Specifically, the static elimination roll 81 is arranged on the lower side between the first secondary transfer position T21 and the second secondary transfer position T22. The static elimination roll 82 is arranged on the upper side between the first secondary transfer position T21 and the second secondary transfer position T22.

Furthermore, the distance L1 between the static elimination roll 81 and the first secondary transfer position T21 is shorter than the distance L2 between the static elimination roll 82 and the second secondary transfer position T22. In other words, the neutralizing rolls 81 and 82 are closer to the first secondary transfer position T21 than to the second secondary transfer position T22. Also, the distance 1 is shorter than the distance L3 between the first secondary transfer position T21 and the second secondary transfer position T22. Note that the distance L2 is the same distance as the distance L3.

More specifically, the neutralizing rolls 81 and 82 are arranged inside (inner peripheral side) of the conveying belt 20 . Specifically, the neutralization rolls 81 and 82 are arranged on the opposite surface 20B (an example of the inner peripheral surface) of the transport belt 20 opposite to the contact surface 20A. In other words, the static elimination rolls 81 and 82 are in contact with the opposite surface 20B.

The neutralization rolls 81 and 82 rotate following the conveyor belt 20 by contacting the opposite surface 20B of the conveyor belt 20 . That is, the neutralization rolls 81 and 82 are driven rolls that are driven to rotate by the conveyor belt 20 .

A voltage is applied between the static elimination rolls 81 and 82 and the secondary transfer roll 47 by, for example, power being supplied from the high-voltage power supply board 66 of the first image forming unit 41 . In this manner, the charge removing rolls 81 and 82 apply a charge of opposite polarity to the recording medium P charged at the first secondary transfer position T21 by applying a voltage to the recording medium P, thereby It is configured to neutralize P.

As described above, since the neutralizing rolls 81 and 82 are in contact with the opposite surface 20B of the transport belt 20, the recording medium P is neutralized by the neutralizing rolls 81 and 82 via the transport belt 20 in this embodiment. be.

It should be noted that the term "static elimination" refers to the elimination (neutralization) of at least a portion of the charges on the charged recording medium P, and is not limited to complete elimination of the charges. That is, it is sufficient that the amount of charge on the recording medium P is reduced and the electrostatic force is weakened. In this embodiment, the voltage applied to the charge removing rolls 81 and 82 is either a positive voltage or a negative voltage depending on the type of the recording medium P. As shown in FIG.

(Drive control of static elimination rolls 81 and 82)
In the present embodiment, the control board 64 as an example of receiving means for receiving information on the recording medium P changes voltages applied to the neutralization rolls 81 and 82 based on the received information on the recording medium P. Specifically, for example, the control board 64 of the first image forming unit 41 receives the type information of the recording medium P, the control board 64 drives and controls the high-voltage power supply board 66 based on the type information of the recording medium P, The voltage applied to the static elimination rolls 81 and 82 is changed (see FIG. 4).

The type information of the recording medium P is an example of the information of the recording medium P, and is information indicating the type of the recording medium P. FIG. The type information of the recording medium P is received by the control board 64 of the first image forming unit 41 when the type of the recording medium P is selected through the UI 17, for example. Note that the type information of the recording medium P may be received from an external device connected to the image forming apparatus 10 . Further, the type of the recording medium P may be detected by a sensor or the like, and the result thereof may be accepted as the type information of the recording medium P. FIG.

Then, for example, when the type of the received type information of the recording medium P is the first type, the control board 64 causes the first voltage to be applied to the charge removing rolls 81 and 82 so that the received type information of the recording medium P is When the type is the second type having a higher resistance than the first type, a second voltage higher than the first voltage is applied to the static elimination rolls 81 and 82 . As a result, the charge amounts of the static elimination rolls 81 and 82 are increased, and the static elimination performance is increased.

In other words, the control board 64 increases the voltage to be applied to the neutralization rolls 81 and 82, for example, when the received type information of the recording medium P is a high resistance type.

In this embodiment, power is supplied from the high-voltage power supply board 66 of the first image forming unit 41 to the static elimination rolls 81 and 82, but the present invention is not limited to this. For example, the high-voltage power supply board 66 of the second image forming unit 42 may be used as the power supply for supplying power to the static elimination rolls 81 and 82 . The high voltage power supply board 66 of the first image forming unit 41 supplies power to one of the static elimination rolls 81 and 82, and the high voltage power supply board 66 of the second image forming unit 42 supplies power to the other of the static elimination rolls 81 and 82. It may be a configuration. Further, power may be supplied from a power supply provided in the apparatus main body 11 to the static elimination rolls 81 and 82 separately from the high voltage power supply board 66 of the first image forming unit 41 and the high voltage power supply board 66 of the second image forming unit 42. good.

<Action according to the present embodiment>
Next, the operation according to this embodiment will be described.

In this embodiment, a secondary transfer electric field is applied between the secondary transfer roll 47 and the drive roll 74A of the first intermediate transfer belt 71, so that the recording medium P conveyed upward by the conveyance belt 20 is A toner image is transferred from the first intermediate transfer belt 71 at the first secondary transfer position T21. At this time, the recording medium P is charged.

The recording medium P charged at the first secondary transfer position T21 is further transported upward by the transport belt 20, and is neutralized between the first secondary transfer position T21 and the second secondary transfer position T22. Static electricity is eliminated by rolls 81 and 82 . The recording medium P neutralized by the neutralization rolls 81 and 82 is further conveyed upward by the conveyor belt 20, and a secondary transfer electric field is applied between the secondary transfer roll 48 and the drive roll 74A of the second intermediate transfer belt 72. As a result, the toner image is transferred from the second intermediate transfer belt 72 at the second secondary transfer position T22.

As described above, in the present embodiment, the recording medium P is neutralized by the neutralization rolls 81 and 82, so that the recording medium P is charged at the first secondary transfer position T21 and is transferred to the second secondary transfer position T21. Compared to the structure in which the toner image is conveyed to T22, the effect on the transferability of the toner image at the second secondary transfer position T22 is suppressed.

Further, in the present embodiment, the neutralization rolls 81 and 82 are arranged inside the transport belt 20 and neutralize the recording medium P via the transport belt 20 . Therefore, the neutralizing rolls 81 and 82 neutralize the static electricity of the recording medium P conveyed by the conveying belt 20 in a non-contact manner. As described above, since the static elimination rolls 81 and 82 are not in contact with the recording medium P, the recording medium P may be peeled off from the conveying belt 20 and the recording medium P may be damaged, as compared with the structure in which the static elimination rolls 81 and 82 are in contact with each other. Wrinkles are suppressed.

Further, in the present embodiment, the neutralizing rolls 81 and 82 are driven rolls that contact the opposite surface 20</b>B of the transport belt 20 and are driven to rotate by the transport belt 20 . For this reason, the frictional resistance with the conveying belt 20 is reduced compared to the configuration in which the neutralizing rolls 81 and 82 slide relative to the conveying belt 20 . In addition, sliding means the state which moves while sliding.

Further, in this embodiment, the transport belt 20 transports the recording medium P upward, and the second intermediate transfer belt 72 and the first intermediate transfer belt 71 overlap vertically in the direction of gravity. For this reason, compared with the configuration in which the conveying belt 20 conveys the recording medium P in the horizontal direction and the entire first intermediate transfer belt 71 is displaced in the horizontal direction with respect to the second intermediate transfer belt 72, the image forming apparatus While reducing the dimension of 10 in the horizontal direction, the effect on the transferability of the toner image at the second secondary transfer position T22 is suppressed.

Further, in the present embodiment, the charge removing rolls 81 and 82 apply a voltage to the recording medium P with a polarity opposite to that of the recording medium P charged at the first secondary transfer position T21. , the recording medium P is destaticized. For this reason, the static elimination rolls 81 and 82 are grounded to a reference potential (ground), thereby increasing the static elimination performance of the static elimination rolls 81 and 82 compared to a configuration in which the static elimination rolls 81 and 82 function as a ground that only releases the charge of the recording medium P.

Further, in this embodiment, the control board 64 drives and controls the high-voltage power supply board 66 based on the type information of the recording medium P, and changes the voltage applied to the static elimination rolls 81 and 82 . For this reason, the charge removing ability of the charge removing rolls 81 and 82 can be changed according to the recording medium P, compared to the configuration in which the voltage applied to the charge removing rolls 81 and 82 is constant.

<Modification>
In the present embodiment, the neutralizing rolls 81 and 82 are arranged inside (inner peripheral side) of the conveying belt 20, but this is not the only option. For example, the neutralizing rolls 81 and 82 may be arranged outside the conveying belt 20 and in the space between the first image forming unit 41 and the second image forming unit 42 . In this configuration, other static elimination means is used instead of the static elimination rolls 81 and 82, and, for example, between the first secondary transfer position T21 and the second secondary transfer position T22, the contact surface 20A side of the conveying belt 20 is discharged. will be placed in In this case, it is necessary to neutralize the recording medium P without disturbing the toner image transferred from the first image forming unit 41 . Therefore, specifically, the static elimination means is arranged to face the contact surface 20A in a non-contact manner, and intersects the traveling direction of the transport belt 20 so that a path for static elimination is formed on the inner surface of the transport belt 20. An electrical path must be formed that wraps around the inner surface from the ends of the direction.

Further, in the present embodiment, the neutralizing rolls 81 and 82 are driven rolls that contact the opposite surface 20B of the conveying belt 20 and are driven to rotate by the conveying belt 20, but this is not the only option. The neutralization rolls 81 and 82 may be configured to slide relative to the revolving conveyor belt 20, for example. Examples of static elimination means in this configuration include a static elimination needle (detack saw) and a static elimination film.

Further, in the present embodiment, a voltage is applied between the static elimination rolls 81 and 82 and the secondary transfer roll 47, but the present invention is not limited to this. For example, a voltage may be applied between the static elimination roll 81 and the static elimination roll 82 .

Further, in this embodiment, the conveying belt 20 conveys the recording medium P upward, but the present invention is not limited to this. For example, the transport belt 20 may be configured to transport the recording medium P downward. Further, the transport belt 20 may be configured to transport the recording medium P in the horizontal direction.

Further, in the present embodiment, the control board 64 changes the voltage applied to the charge removing rolls 81 and 82 based on the type information of the recording medium P, but the present invention is not limited to this. For example, the voltage applied to the static elimination rolls 81 and 82 may be constant.

Moreover, in the present embodiment, voltage is applied to the static elimination rolls 81 and 82, but the present invention is not limited to this. For example, the neutralizing rolls 81 and 82 may be grounded to a reference potential (ground) to function as a ground for releasing the charge of the charged recording medium P. Anything that removes at least part of the charge of P may be used.

Further, in the present embodiment, the first image forming unit 41 has four toner image forming units 50 that form toner images of a total of four colors of yellow (Y), magenta (M), cyan (C), and white (W). The second image forming unit 42 has four toner image forming units 50, which form toner images of a total of four colors: transparent (T), silver (S), gold (G), and black (K). Although it had the formation part 50, it is not restricted to this. For example, the toner image forming units 50 of the colors of the first image forming unit 41 and the second image forming unit 42 may be partially or entirely interchanged, and the toner images of colors other than the above may be arranged. You may have the forming part 50 .

Also, in the present embodiment, each of the first image forming unit 41 and the second image forming unit 42 has four toner image forming units 50, but the present invention is not limited to this. Each of the first image forming unit 41 and the second image forming unit 42 may have two, three, or five or more toner image forming units 50 . That is, each of the first image forming unit 41 and the second image forming unit 42 may be configured to have a plurality of toner image forming units 50 .

Further, in the present embodiment, the image forming section 14 has two image forming units (the first image forming unit 41 and the second image forming unit 42, but is not limited to this.) The image forming section 14 Furthermore, a third image forming unit may be provided, and the image forming section 14 may be configured to have three or more image forming units.

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 20 Conveyor belt 38 Conveyor path 64 Control board (an example of receiving means)
71 first intermediate transfer belt 72 second intermediate transfer belts 81, 82 static elimination roll (an example of static elimination means)
P recording medium T21 first secondary transfer position (an example of a first transfer position)
T22 second secondary transcription position (an example of a second transcription position)

Claims (6)

a conveying belt arranged along the conveying path and in contact with one side of the recording medium to convey the recording medium;
a first intermediate transfer belt on which an image is transferred at a first transfer position onto a recording medium conveyed by the conveying belt;
a second intermediate transfer belt on which an image is transferred onto a recording medium conveyed by the conveying belt at a second transfer position downstream of the first transfer position in the conveying direction;
a neutralizing means disposed between the first transfer position and the second transfer position for neutralizing the recording medium charged at the first transfer position;
with
a plurality of the static eliminating means are provided between the first transfer position and the second transfer position;
Toner images are transferred to the first intermediate transfer belt by a plurality of toner image forming units,
The distance between the upstream static elimination unit among the plurality of static elimination units and the first transfer position is longer than the distance between the downstream static elimination unit among the plurality of static elimination units and the second transfer position. getting shorter
Image forming device. The conveying belt is formed in an annular shape, and conveys the recording medium with an outer peripheral surface thereof in contact with one side of the recording medium;
The neutralizing means is disposed inside the conveying belt and neutralizes the recording medium via the conveying belt.
The image forming apparatus according to claim 1. The static elimination unit is a driven roll that contacts the inner peripheral surface of the transport belt and rotates following the transport belt.
The image forming apparatus according to claim 2. the conveying belt conveys the recording medium from the lower side to the upper side in the direction of gravity;
The first intermediate transfer belt and the second intermediate transfer belt overlap vertically in the direction of gravity.
The image forming apparatus according to any one of claims 1 to 3. When a voltage is applied to the charge removing unit, the charge of the polarity opposite to that of the recording medium charged at the first transfer position is applied to the recording medium.
The image forming apparatus according to any one of claims 1 to 4. A receiving means for receiving information on the recording medium,
changing the voltage applied to the static elimination means based on the information received by the reception means;
The image forming apparatus according to claim 5.

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