JP7305941B2 - 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, in a configuration in which an image is transferred from each of the first intermediate transfer belt and the second intermediate transfer belt to a recording medium conveyed by a conveying belt arranged along a conveying path extending in the longitudinal direction, In a configuration in which only one intermediate transfer belt sandwiches the recording medium between itself and the conveying belt, the first intermediate transfer belt and the second intermediate transfer belt are arranged at a distance exceeding the conveying direction length of the recording medium. . Therefore, the space between the first intermediate transfer belt and the second intermediate transfer belt becomes large.

The present invention reduces the space between the first intermediate transfer belt and the second intermediate transfer belt as compared with the configuration in which the recording medium is sandwiched only between the conveying belt and the single intermediate transfer belt, and the recording medium is provided at a plurality of locations. An object of the present invention is to provide an image forming apparatus capable of transferring an image at a high speed.

In a first aspect, a transport belt is arranged along a transport path extending in the vertical direction and contacts one side of a recording medium to transport the recording medium; a first intermediate transfer belt on which is transferred, and a recording medium disposed above the first intermediate transfer belt and sandwiched between the first intermediate transfer belt and the transport belt, and a second intermediate transfer belt onto which the image is transferred onto the recording medium.

A second aspect comprises a first image forming unit having the first intermediate transfer belt, and a second image forming unit disposed above the first image forming unit and having the second intermediate transfer belt, The upper end of the first image forming section overlaps the second image forming section when viewed in the horizontal direction.

In the third aspect, the first image forming section has a circuit board arranged above the first intermediate transfer belt, and the upper end of the circuit board is positioned above the second image forming section when viewed in a horizontal direction. overlapping.

In the fourth aspect, the first intermediate transfer belt and the second intermediate transfer belt are inclined in the same direction with respect to the contact surface of the transport belt with the recording medium.

In the fifth aspect, the lower end of the first intermediate transfer belt and the upper end of the second intermediate transfer belt are arranged within the vertical height of the transport belt.

A sixth aspect is a pair of rolls around which each of the first intermediate transfer belt and the second intermediate transfer belt is wound, the first roll facing the conveying belt via the intermediate transfer belt; and a second roll disposed on the opposite side of the first roll from the conveying belt side.

In a seventh aspect, the an electric charge imparting means for imparting an electric charge to the conveying belt for attracting a recording medium to the conveying belt.

In the eighth aspect, the charge imparting means is arranged on the surface of the conveying belt opposite to the contact surface with the recording medium.

In the ninth aspect, the charge imparting means imparts the charge to the transport belt when the transport belt transports a second recording medium that is thinner than the first recording medium as the recording medium.

A tenth aspect includes a drive roll around which the transport belt is wound and which is driven to rotate, a first transfer position at which an image is transferred from the first intermediate transfer belt, and a position at which an image is transferred from the second intermediate transfer belt. and the second transfer position is an integral multiple of the circumference of the drive roll.

According to the configuration of the first aspect, compared to the configuration in which the recording medium is sandwiched between only the conveying belt and the single intermediate transfer belt, while reducing the space between the first intermediate transfer belt and the second intermediate transfer belt, Images can be transferred to a recording medium at multiple locations.

According to the configuration of the second aspect, compared to the configuration in which the upper end of the first image forming section is arranged below the lower end of the second image forming section, the distance between the first intermediate transfer belt and the second intermediate transfer belt space can be reduced.

According to the configuration of the third aspect, the space between the first intermediate transfer belt and the second intermediate transfer belt is different from the configuration in which the upper end of the circuit board is arranged below the lower end of the second image forming section. can be made smaller.

According to the configuration of the fourth aspect, compared to the configuration in which the first intermediate transfer belt and the second intermediate transfer belt are inclined in different directions with respect to the contact surface, the distance between the first intermediate transfer belt and the second intermediate transfer belt space can be reduced.

According to the configuration of the fifth aspect, compared to the configuration in which the lower end of the first intermediate transfer belt and the upper end of the second intermediate transfer belt are arranged outside the height of the conveying belt in the vertical direction, the first intermediate transfer belt and the second intermediate transfer belt can be reduced.

According to the configuration of the sixth aspect, compared to the configuration in which each of the first intermediate transfer belt and the second intermediate transfer belt is wound around three or more rolls, each of the first intermediate transfer belt and the second intermediate transfer belt The dimension in the height direction can be reduced.

According to the configuration of the seventh aspect, compared to the configuration in which the recording medium is conveyed by the conveying belt in a state where no charge is applied between the first transfer position and the second transfer position, the recording after passing the first transfer position is performed. It is possible to suppress the separation of the medium from the conveying belt.

According to the configuration of the eighth aspect, the recording medium can be attracted to the conveying belt without contacting the recording medium conveyed by the conveying belt.

According to the configuration of the ninth aspect, compared to the configuration in which the recording medium is conveyed by the conveying belt to which no charge is applied between the first transfer position and the second transfer position, the second recording medium is thinner than the first recording medium. In the second recording medium, it is possible to suppress the separation of the second recording medium that has passed the first transfer position from the conveying belt.

According to the configuration of the tenth aspect, compared to the configuration in which the distance between the first transfer position and the second transfer position is different from the integral multiple of the circumference of the drive roll, the first transfer position and the second transfer position due to the eccentricity of the drive roll It is possible to suppress transfer deviation from the transfer position.

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 for controlling the operation of the charge imparting roll according to the embodiment; FIG. 2 is a schematic diagram showing configurations of a conveying belt, a first intermediate transfer belt, and a second intermediate transfer belt according to the embodiment; FIG. 11 is a schematic diagram showing the arrangement of a second image forming unit according to a modified example;

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 figure 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, a storage section 12, a discharge section 18, a conveying section 13, an image forming section 14, and a fixing device 19. , charge applying 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 charge applying 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 (direction of arrow A) by a motor 68 of the second image forming unit 42, which will be described later, for example, so that the transport belt 20 is rotated in one direction (direction of arrow B). do.

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. 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 first image forming unit 41 is an example of a first image forming section. The second image forming unit 42 is an example of a second image forming section.

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. Furthermore, the arrangement of components (components) constituting the image forming unit 14 will be described.

[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. 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. 2, the front wall 60F and the left wall 60L (side wall) 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 holding the toner images transferred from the photosensitive drums 52 of the respective colors of the first image forming unit 41 . Further, the first intermediate transfer belt 71 has a function of conveying the held toner image 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 . The pair of rolls 74 is arranged on a drive roll 74A (an example of a first roll) facing the transport belt 20 via the first intermediate transfer belt 71, and on the opposite side (left side) of the drive roll 74A from the transport belt 20 side. and a driven roll 74B (an example of a second roll). The first intermediate transfer belt 71 is wound only around the drive roll 74A and the driven roll 74B while being tensioned. 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) that contacts the conveying 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 board 62 is an example of a circuit board.

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 configured with a ROM (rom) in which a program is recorded, a storage, or 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 . , developing device 56, four primary transfer rolls 75, secondary transfer rolls 47 and 48, charge applying 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 . 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 drives, for example, the photosensitive drum 52, the developing roll 56A of the developing device 56, the drive roll 74A around which the second intermediate transfer belt 72 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 belt 72]
The second intermediate transfer belt 72 is configured similarly to the first intermediate transfer belt 71 of the first image forming unit 41, and includes a driving roll 74A (an example of a first roll) and a driven roll 74B (an example of a second roll). It is wrapped around only a pair of rolls 74 composed of and. The second intermediate transfer belt 72 has the function of holding the toner images transferred from the respective color photosensitive drums 52 of the second image forming unit 42 and conveying the toner images to the second secondary transfer position T22. are doing.

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 .

Specifically, in this embodiment, when the recording medium P is conveyed by the conveying belt 20 , it is first sandwiched between the first intermediate transfer belt 71 and the conveying belt 20 and and the conveying belt 20 are not sandwiched. In the course of being conveyed by the conveying belt 20, the recording medium P is sandwiched between the first intermediate transfer belt 71 and the conveying belt 20 and between the second intermediate transfer belt 72 and the conveying belt 20. . Further, in the process of being conveyed by the conveying belt 20, the recording medium P is not sandwiched between the first intermediate transfer belt 71 and the conveying belt 20, but is sandwiched between the second intermediate transfer belt 72 and the conveying belt 20. Become. In other words, the leading edge of the recording medium P enters the second secondary transfer position T22 before the trailing edge of the recording medium P leaves the first secondary transfer position T21.

In this embodiment, a recording medium P of a standard size (for example, A4 size) is sandwiched between the first intermediate transfer belt 71 and the transport belt 20, and the recording medium P is placed between the second intermediate transfer belt 72 and the transport belt. 20 are sandwiched between them. The standard size can also be said to be the most frequent size. In a state in which recording media P of all sizes including the minimum size that can be transported by the image forming apparatus 10 are sandwiched between the first intermediate transfer belt 71 and the transport belt 20, the recording media P are transferred to the second intermediate transfer belt. The belt 72 and the transport belt 20 may be sandwiched between them. Furthermore, in this embodiment, at least the recording medium P of the maximum size that can be transported by the image forming apparatus 10 is sandwiched between the first intermediate transfer belt 71 and the transport belt 20, and the recording medium P is transported. It is sufficient that the second intermediate transfer belt 72 and the transport belt 20 are sandwiched between them.

[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 voltage applied to the secondary transfer roll 48 is, for example, 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 between 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.

(Arrangement of Components of Image Forming Unit 14)
Arrangement of components of the image forming unit 14 will be described. In the following, the arrangement of the first image forming unit 41 and each part of the first image forming unit 41 and each part of the second image forming unit 42 and second image forming unit 42 will be described.

As shown in FIG. 1 , the first image forming unit 41 is specifically arranged on the upper side of the storage section 12 and on the left side of the conveying belt 20 . 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 . Specifically, the first image forming unit 41 and the second image forming unit 42 are arranged to overlap each other in the vertical direction. In other words, at least part of the first image forming unit 41 overlaps at least part of the second image forming unit 42 when viewed in the vertical direction.

More specifically, the second intermediate transfer belt 72 that is part of the second image forming unit 42 is placed above the first intermediate transfer belt 71 that is part of the first image forming unit 41 . are arranged so that they overlap vertically.

Further, in the present embodiment, as described above, in a state in which the recording medium P of standard size (for example, A4 size) is sandwiched between the first intermediate transfer belt 71 and the transport belt 20, the recording medium P is transferred to the second The intermediate transfer belt 72 and the transport belt 20 are sandwiched between them.

In other words, the distance LA (see FIG. 2) between the first secondary transfer position T21 and the second secondary transfer position T22 is set shorter than the length of the standard size recording medium P along the transport direction. , a first intermediate transfer belt 71 and a second intermediate transfer belt 72 are arranged.

Further, the distance LA between the first secondary transfer position T21 and the second secondary transfer position T22 is an integral multiple (n times) of the circumference S of the drive roll 22B around which the transport belt 20 is wound. there is Specifically, LA=nS±α (0≦α≦S/10) may be satisfied.

A distance L1 from the first secondary transfer position T21 to the lower end of the contact surface 20A of the transport belt 20 is longer than a distance L5 from the second secondary transfer position T22 to the lower end of the contact surface 20A of the transport belt 20. ing.

The upper end of the first image forming unit 41 overlaps the second image forming unit 42 when viewed in the horizontal direction (viewed in the horizontal direction). In other words, the upper end of the first image forming unit 41 is arranged above (higher than) the lower end of the second image forming unit 42 .

Specifically, the first image forming unit 41 has a power board 62 at its upper end, and the upper end of the power board 62 overlaps the second image forming unit 42 when viewed in the horizontal direction. More specifically, the power board 62 has an electronic component 62A at its upper end, and the electronic component 62A overlaps the second image forming unit 42 when viewed in the horizontal direction. In other words, the electronic component 62A of the power supply board 62 of the first image forming unit 41 is arranged above (higher than) the lower end of the second image forming unit 42. As shown in FIG. In FIG. 2, a line extending in the left-right direction (horizontal direction) from the upper end of the first image forming unit 41 (the upper end of the electronic component 62A) is denoted by H1.

The first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined in the same direction with respect to the contact surface 20A of the transport belt 20 . Specifically, as shown in FIG. 5, both the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined such that the angle θ with respect to the contact surface 20A of the transport belt 20 is an obtuse angle. . More specifically, both the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined diagonally upward to the left. More specifically, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined at the same angle.

Here, the reference of the angle between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is, for example, the angle at the contact surfaces 71A and 72A (lower surfaces) with which the photosensitive drums 52 come into contact.

In addition, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are arranged above the contact surfaces 71A and 72A, and the non-contact surfaces 71B and 72B, which are not in contact with the photosensitive drums 52, are arranged along the contact surfaces 71A and 72A. are placed. Therefore, even when the non-contact surfaces 71B and 72B are used as a reference, the angles of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are the same as the angles of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 when the contact surfaces 71A and 72A are used as a reference. The angles of the belt 71 and the second intermediate transfer belt 72 are grasped.

Further, a line 70L connecting the rotation axis of the drive roll 74A and the rotation axis of the driven roll 74B of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is also arranged along the contact surfaces 71A and 72A. Therefore, even when the line 70L is used as a reference, the angles of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are the same as the angles of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 when the contact surfaces 71A and 72A are used as the reference. The angle of the two intermediate transfer belts 72 is grasped.

The first intermediate transfer belt 71 is arranged above the lower end of the transport belt 20 . On the other hand, the upper end of the second intermediate transfer belt 72 is arranged above the upper end of the conveying belt 20 . Specifically, the upper end of the portion of the second intermediate transfer belt 72 wound around the driven roll 74B is higher than the upper end of the portion of the transport belt 20 wound around the driving roll 22B (higher position). ). In FIG. 2, a line extending in the left-right direction (horizontal direction) from the upper end of the conveying belt 20 is denoted by H2. 1 and 2, the upper end of the second intermediate transfer belt 72 is denoted by 70U.

Further, the upper end of the second intermediate transfer belt 72 is arranged below the upper end of the fixing device 19 as shown in FIG. Specifically, the upper end of the portion of the second intermediate transfer belt 72 that is wrapped around the driven roll 74B is positioned below (lower than) the heating roll 92 and the pressure roll 94 of the fixing device 19. ing.

(Charging rolls 81, 82)
In this embodiment, the contact areas 71N and 72N of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are in contact with the transport belt 20 . Since the first intermediate transfer belt 71 and the conveying belt 20 are belt members, they are easily deformed to each other. easier. Therefore, it is necessary to reduce the separation of the passing recording medium P from the transport belt 20 . The charge imparting rolls 81 and 82 shown in FIG. 2 are an example of charge imparting means for imparting to the transport belt 20 an electrical charge for attracting the recording medium P to the transport belt 20 . The charge applying rolls 81 and 82 are arranged between the first secondary transfer position T21 and the second secondary transfer position T22. Specifically, the charge applying roll 81 is arranged on the lower side between the first secondary transfer position T21 and the second secondary transfer position T22. The charge applying 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 L2 between the charge applying roll 81 and the first secondary transfer position T21 is shorter than the distance L4 between the charge applying roll 82 and the second secondary transfer position T22. In other words, it can be said that the charge applying rolls 81 and 82 are closer to the first secondary transfer position T21 than to the second secondary transfer position T22. Also, the distance L2 is shorter than the distance L3 between the first secondary transfer position T21 and the second secondary transfer position T22. Note that the distance L3 is the same distance as the distance L4.

More specifically, the charge applying rolls 81 and 82 are arranged inside (inner peripheral side) of the conveying belt 20 . Specifically, the charge applying rolls 81 and 82 are arranged on the opposite surface 20B (inner peripheral surface) of the conveying belt 20 opposite to the contact surface 20A. In other words, the charge application rolls 81, 82 are in contact with the opposite surface 20B. The charge applying rolls 81 and 82 rotate following the conveyor belt 20 by contacting the opposite surface 20B of the conveyor belt 20 . That is, the charge applying rolls 81 and 82 can also be said to be driven rolls that are driven to rotate by the conveying belt 20 .

A voltage is applied between the charge applying 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 . As a result, the charge applying rolls 81 and 82 apply charges to the transport belt 20 between the first secondary transfer position T21 and the second secondary transfer position T22 so that the recording medium P is attracted to the transport belt 20. Then, the recording medium P is attracted to the conveying belt 20 by the electrostatic force generated by this charge.

Here, in this embodiment, the type of recording medium P selected through the UI 17 connected to the control board 64 of the first image forming unit 41 is a recording medium P having a thickness less than the reference thickness (for example, 0.08 mm). , the control board 64 is supplied with power from the high-voltage power supply board 66 . In other words, when the transport belt 20 transports a recording medium P thinner than the recording medium P having the reference thickness, the transport belt 20 is given an electric charge that attracts the recording medium P to the transport belt 20 . Further, when the conveying belt 20 conveys a recording medium having a thickness equal to or larger than the reference thickness, the conveying belt 20 is not provided with the electric charge for attracting the recording medium P to the conveying belt 20 .

The recording medium P having the reference thickness is an example of a first recording medium, and the recording medium P having a thickness less than the reference thickness is an example of a second recording medium. Further, the recording medium P having the reference thickness may be plain paper. Further, in the present embodiment, the thickness (mm) of the recording medium P is used as the reference for the thinness of the recording medium P, but the basis weight (g/m ² ) of the recording medium P may be used, for example. In this embodiment, the voltage applied to the charge applying rolls 81 and 82 is either a positive voltage or a negative voltage depending on the type of the recording medium P. FIG.

Further, in the present embodiment, power is supplied from the high-voltage power supply board 66 of the first image forming unit 41 to the charge applying 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 charge applying rolls 81 and 82 . The high voltage power supply board 66 of the first image forming unit 41 supplies power to one of the charge applying 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 charge applying rolls 81 and 82. It may be configured to supply. Further, power is supplied to the charge applying rolls 81 and 82 from a power supply provided in the apparatus main body 11 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 too.

Further, since the charge applying rolls 81 and 82 have a function of assisting the transport of the recording medium P by the transport belt 20 , they may be grasped as components forming part of the transport section 13 .

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

According to the image forming apparatus of the present embodiment, the recording medium P is placed between the first intermediate transfer belt 71 and the transport belt 20 at the first secondary transfer position T21, and the recording medium P is transferred to the second intermediate transfer belt. The transfer belt 72 and the transport belt 20 are sandwiched at the second secondary transfer position T22.

Here, in the configuration having the first intermediate transfer belt 71 and the second intermediate transfer belt 72, the recording medium P can be transferred with only a single intermediate transfer belt (only one of the first intermediate transfer belt 71 and the second intermediate transfer belt 72). is sandwiched between the belt 20 and the transport belt 20 (first configuration), the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are separated from each other by a distance exceeding the length of the recording medium P in the transport direction. . Therefore, the space between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 becomes large.

In contrast, in the present embodiment, as described above, the recording medium P sandwiched between the first intermediate transfer belt 71 and the transport belt 20 is sandwiched between the second intermediate transfer belt 72 and the transport belt 20. , the space between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is reduced compared to the first configuration, and the toner image can be transferred to the recording medium P at a plurality of locations. In other words, according to the configuration of this embodiment, the distance between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 can be shortened compared to the first configuration. In other words, according to the configuration of this embodiment, the distance between the first secondary transfer position T21 and the second secondary transfer position T22 can be shortened compared to the first configuration.

Further, in this embodiment, the upper end of the first image forming unit 41 overlaps the second image forming unit 42 when viewed in the horizontal direction (viewed in the horizontal direction). Therefore, compared to the configuration (second configuration) in which the upper end of the first image forming unit 41 is arranged below the lower end of the second image forming unit 42 (second configuration), the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are arranged. shorten the distance to In other words, the space between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is smaller than in the second configuration.

Further, in the present embodiment, the upper end of the power supply board 62 of the first image forming unit 41 overlaps the second image forming unit 42 when viewed in the horizontal direction. Therefore, compared to the configuration (third configuration) in which the upper end of the power supply board 62 is arranged below the lower end of the second image forming unit 42, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are separated from each other. shorten the distance. In other words, the space between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is smaller than in the third configuration.

Further, in this embodiment, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined in the same direction with respect to the contact surface 20A of the transport belt 20 .

Here, in a configuration (fourth configuration) in which the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined in different directions with respect to the contact surface 20A of the conveying belt 20, the first intermediate transfer belt 71 and the second intermediate transfer belt 71 are inclined in different directions. A dead space with the intermediate transfer belt 72 is likely to occur. For example, in a configuration in which the first intermediate transfer belt 71 inclines diagonally upward to the left and the second intermediate transfer belt 72 inclines diagonally upward to the right, the first intermediate transfer belt 71 and the second intermediate transfer belt A dead space is likely to occur in the right portion between 72. Further, for example, in a configuration in which the first intermediate transfer belt 71 is tilted diagonally upward to the right and the second intermediate transfer belt 72 is tilted diagonally upward to the left, the first intermediate transfer belt 71 and the second intermediate transfer belt 71 are tilted diagonally upward. A dead space is likely to occur in the left portion between the transfer belt 72 and the transfer belt 72 . As described above, in the fourth configuration, a dead space tends to occur, and the space between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 tends to increase.

In contrast, in the present embodiment, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined in the same direction with respect to the contact surface 20A of the conveying belt 20. , the dead space is less likely to occur, and the space between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 becomes smaller.

Further, in the present embodiment, each of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 includes a drive roll 74A facing the transport belt 20 via the first intermediate transfer belt 71 and a transport belt facing the drive roll 74A. 20 side and the driven roll 74B arranged on the opposite side.

Therefore, the height of each of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is higher than that of the structure in which each of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is wound around three or more rolls. Directional dimension becomes smaller. In particular, in this embodiment, since the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are arranged obliquely, when the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are arranged horizontally, In comparison, the dimensions in the height direction of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 tend to be large. Therefore, it is effective to reduce the dimension in the height direction of each of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 by winding them around the drive roll 74A and the driven roll 74B.

Further, in the present embodiment, the charge imparting rolls 81 and 82 convey charges for attracting the recording medium P to the conveying belt 20 between the first secondary transfer position T21 and the second secondary transfer position T22. The recording medium P is attracted to the conveying belt 20 by the electrostatic force generated by this charge.

For this reason, compared to the configuration (fifth configuration) in which the recording medium P is transported between the first secondary transfer position T21 and the second secondary transfer position T22 by the transport belt 20 to which no charge is applied. , the separation of the recording medium P that has passed the first secondary transfer position T21 from the conveying belt 20 is suppressed.

In particular, in the present embodiment, when the conveying belt 20 conveys a recording medium P thinner than the recording medium P having the reference thickness, the conveying belt 20 is given an electric charge for attracting the recording medium P to the conveying belt 20. As compared with the fifth configuration, separation of the recording medium P that has passed the first secondary transfer position T21 from the conveying belt 20 is suppressed when the recording medium P is thinner than the recording medium P having the reference thickness. In particular, this configuration is effective because the recording medium P thinner than the recording medium P having the reference thickness is easier to separate from the conveying belt 20 than the recording medium P having the reference thickness.

Further, in this embodiment, the charge applying rolls 81 and 82 are arranged on the opposite surface 20B (inner peripheral surface) of the conveying belt 20 opposite to the contact surface 20A. Therefore, the recording medium P is attracted to the conveying belt 20 without contact with the recording medium P conveyed by the conveying belt 20 .

Further, in the present embodiment, the distance LA between the first secondary transfer position T21 and the second secondary transfer position T22 is an integral multiple (n times).

Therefore, compared to the configuration (sixth configuration) in which the distance between the first secondary transfer position T21 and the second secondary transfer position T22 is an integral multiple of the circumference of the drive roll 22B, the distance between the drive roll 22B Velocity fluctuation of the transport belt 20 due to eccentricity tends to occur at the same period at the first secondary transfer position T21 and the second secondary transfer position T22. Accordingly, compared to the sixth configuration, the transfer deviation between the first secondary transfer position T21 and the second secondary transfer position T22 due to the eccentricity of the drive roll 22B is suppressed.

<Modified Example of Arrangement of First Intermediate Transfer Belt 71 and Second Intermediate Transfer Belt 72>
In this embodiment, the first intermediate transfer belt 71 is arranged above the lower end of the transport belt 20, and the upper end of the second intermediate transfer belt 72 is arranged above the upper end of the transport belt 20. is not limited to

As shown in FIG. 6, for example, even if the lower end of the first intermediate transfer belt 71 and the upper end of the second intermediate transfer belt 72 are arranged within the height of the transport belt 20 in the vertical direction. good.

That is, the first intermediate transfer belt 71 may be arranged above the lower end of the transport belt 20 and the upper end of the second intermediate transfer belt 72 may be arranged below the upper end of the transport belt 20 . In FIG. 6, a line extending in the left-right direction (horizontal direction) from the upper end of the conveying belt 20 is denoted by H2. Further, in FIG. 6, the upper end of the second intermediate transfer belt 72 is indicated by 70U.

According to this modification, the lower end of the first intermediate transfer belt 71 and the upper end of the second intermediate transfer belt 72 are arranged outside the height of the conveying belt 20 in the vertical direction (seventh configuration). , the distance between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is shortened. In other words, the space between the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is smaller than in the seventh configuration. In addition, in this modified example, the upper end of the first image forming unit 41 overlaps the second image forming unit 42 more in the horizontal direction (left and right direction) than in the configuration shown in FIG.

<Other Modifications>
In the present embodiment, the upper end of the first image forming unit 41 overlaps the second image forming unit 42 when viewed in the horizontal direction (viewed in the horizontal direction), but this is not the only option. For example, the upper end of the first image forming unit 41 may be arranged below the lower end of the second image forming unit 42 .

Further, in the present embodiment, the upper end of the power supply board 62 of the first image forming unit 41 overlaps the second image forming unit 42 when viewed in the horizontal direction, but the present invention is not limited to this. For example, the upper end of the power supply board 62 may be arranged below the lower end of the second image forming unit 42 .

Also, in the present embodiment, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined at the same angle with respect to the contact surface 20A of the transport belt 20, but this is not restrictive. For example, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 may be inclined at different angles with respect to the contact surface 20A of the transport belt 20 .

Further, in the present embodiment, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 are inclined in the same direction with respect to the contact surface 20A of the transport belt 20, but this is not restrictive. For example, the first intermediate transfer belt 71 and the second intermediate transfer belt 72 may be configured to tilt in different directions with respect to the contact surface 20A of the transport belt 20 . Furthermore, at least one of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 may be arranged horizontally.

Further, in the present embodiment, the charge imparting rolls 81 and 82 convey charges for attracting the recording medium P to the conveying belt 20 between the first secondary transfer position T21 and the second secondary transfer position T22. Although it is configured to be applied to the belt 20, it is not limited to this. For example, the recording medium P may be transported between the first secondary transfer position T21 and the second secondary transfer position T22 by the transport belt 20 that is not charged.

Further, in the present embodiment, when the transport belt 20 transports a recording medium P thinner than the recording medium P having the reference thickness, the transport belt 20 is provided with an electric charge that attracts the recording medium P to the transport belt 20 . However, it is not limited to this. For example, regardless of the thickness of the recording medium P, an electric charge may be applied to the conveyor belt 20 to attract the recording medium P to the conveyor belt 20 .

Further, in the present embodiment, a voltage is applied between the charge imparting rolls 81 and 82 and the secondary transfer roll 47, but the present invention is not limited to this. For example, a configuration in which a voltage is applied between the charge applying roll 81 and the charge applying roll 82 may be employed.

Further, in the present embodiment, each of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 is wound around the drive roll 74A and the driven roll 74B, but the present invention is not limited to this. For example, each of the first intermediate transfer belt 71 and the second intermediate transfer belt 72 may be wound around three or more rolls.

Further, in the present embodiment, the distance LA between the first secondary transfer position T21 and the second secondary transfer position T22 is an integral multiple (n times), but it is not limited to this. For example, the distance between the first secondary transfer position T21 and the second secondary transfer position T22 may be different from an integral multiple of the circumference of the drive roll 22B.

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, or may be configured to transport the recording medium P in the vertical direction.

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. It may have a forming portion 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 .

Moreover, 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 the present invention is not limited to this. The image forming section 14 may further have a third image forming unit, and the image forming section 14 may be configured to have three or more image forming units.

Further, in the present embodiment, the image forming section 14 has two intermediate transfer belts (the first intermediate transfer belt 71 and the second intermediate transfer belt 72), but the present invention is not limited to this. The image forming section 14 may further have a third intermediate transfer belt, and the image forming section 14 may be configured to have three or more intermediate transfer belts.

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 20A Contact surface 22B Drive roll 38 Conveyance path 41 First image forming unit (an example of a first image forming section)
42 second image forming unit (an example of a second image forming section)
62 Power supply board (an example of a circuit board)
71 first intermediate transfer belt 72 second intermediate transfer belt 74 pair of rolls 74A drive roll (an example of the first roll)
74B driven roll (an example of a second roll)
81 charge-giving roll (an example of charge-giving means)
82 charge-giving roll (an example of charge-giving 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 (9)

a conveying belt arranged along a conveying path extending in the longitudinal direction and contacting one side of a recording medium to convey the recording medium;
a first intermediate transfer belt sandwiching a recording medium with the conveying belt and transferring an image onto the recording medium at a transfer position;
A second transfer belt which is disposed above the first intermediate transfer belt, sandwiches the recording medium sandwiched between the first intermediate transfer belt and the transport belt, and transfers an image onto the recording medium. an intermediate transfer belt;
a first image forming unit having the first intermediate transfer belt;
a second image forming unit disposed above the first image forming unit and having the second intermediate transfer belt;
with
the recording medium is conveyed to the transfer position while being in contact with the conveying belt from an upstream side of the transfer position on the conveying path;
A forming unit for forming an image to be transferred to the first intermediate transfer belt is provided below the first intermediate transfer belt,
The first image forming unit has a circuit board arranged above the first intermediate transfer belt,
The upper end of the circuit board overlaps the second image forming unit when viewed in the horizontal direction.
Image forming device. The image forming apparatus according to claim 1, wherein the first intermediate transfer belt and the second intermediate transfer belt are inclined in the same direction with respect to a contact surface of the conveying belt with the recording medium. 3. The image forming apparatus according to claim 2, wherein the lower end of the first intermediate transfer belt and the upper end of the second intermediate transfer belt are arranged within the vertical height of the transport belt. a conveying belt arranged along a conveying path extending in the longitudinal direction and contacting one side of a recording medium to convey the recording medium;
a first intermediate transfer belt sandwiching a recording medium with the conveying belt and transferring an image onto the recording medium;
A second recording medium disposed above the first intermediate transfer belt and sandwiched between the first intermediate transfer belt and the conveying belt and having an image transferred onto the recording medium. an intermediate transfer belt;
a first image forming unit having the first intermediate transfer belt;
a second image forming unit disposed above the first image forming unit and having the second intermediate transfer belt;
with
the first intermediate transfer belt and the second intermediate transfer belt are inclined in the same direction with respect to the contact surface of the transport belt with the recording medium;
The lower end of the first intermediate transfer belt and the upper end of the second intermediate transfer belt are arranged within the vertical height of the transport belt,
A forming unit for forming an image to be transferred to the first intermediate transfer belt is provided below the first intermediate transfer belt,
The first image forming unit has a circuit board arranged above the first intermediate transfer belt,
The upper end of the circuit board overlaps the second image forming unit when viewed in the horizontal direction.
Image forming device. A pair of rolls around which each of the first intermediate transfer belt and the second intermediate transfer belt is wound, the first roll facing the conveying belt through the intermediate transfer belt, and the first roll 5. The image forming apparatus according to any one of claims 2 to 4, further comprising the pair of rolls including a second roll arranged on the side opposite to the conveying belt side. arranged between a first transfer position where the image is transferred from the first intermediate transfer belt and a second transfer position where the image is transferred from the second intermediate transfer belt, and conveys the recording medium; an electric charge imparting means for imparting an electric charge to the conveying belt to be attracted to the belt;
The image forming apparatus according to any one of claims 1 to 5, comprising: The charge imparting means is arranged on the surface of the conveying belt opposite to the contact surface with the recording medium.
The image forming apparatus according to claim 6. The charge imparting means is
imparting the electric charge to the conveying belt when the conveying belt conveys a second recording medium that is thinner than the first recording medium as the recording medium;
The image forming apparatus according to claim 6 or 7. A driving roll around which the conveying belt is wound and driven to rotate,
The distance between the first transfer position where the image is transferred from the first intermediate transfer belt and the second transfer position where the image is transferred from the second intermediate transfer belt is an integer of the circumference of the drive roll. double
The image forming apparatus according to any one of claims 1 to 8.

Images