JP6769205B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

As shown in FIG. 2, Patent Document 1 includes an image forming engine including a photoconductor drum, an intermediate transfer belt, a secondary transfer roller, a fuser, and a cleaning member to clean the intermediate transfer belt. An image forming unit including a cleaning device for cleaning is disclosed. Further, Patent Document 1 discloses that an image forming portion forms a toner band formed as a band-shaped image formed on a photoconductor drum by using toners of each color. It is said that some toner bands are formed to protect the cleaning member.

Japanese Unexamined Patent Publication No. 2013-29723

The present invention is compared to an image forming apparatus that forms a band image from one end side to the other end side in the width direction of the orbiting body in a region other than the contact area of the medium in the orbiting body when the borderless image is transferred to the medium. Therefore, the purpose is to suppress poor image removal by the removing unit.

The image forming apparatus according to claim 1 is a transfer that circulates in one direction and transfers an image to a medium by sandwiching a medium between the orbiting body on which an image transferred to the medium is formed and the orbiting body while rotating. When the edgeless image is transferred to the medium, the peripheral body forms an image protruding from the contact area of the medium, and the portion, the removing portion that comes into contact with the transfer portion and removes the band image attached to the transfer portion. It is provided with a forming portion for forming the band image in a region other than the contact region in the orbiting body and in a region other than the region where the protruding portion of the image overlaps in one direction.

The image forming apparatus according to claim 2 is a transfer that circulates in one direction and transfers an image to a medium by sandwiching the medium between the orbiting body on which the image to be transferred to the medium is formed and the orbiting body while rotating. When the edgeless image is transferred to the medium, the peripheral body forms an image protruding from the contact area of the medium, and the portion, the removing portion that comes into contact with the transfer portion and removes the band image attached to the transfer portion. It is provided with a forming portion for forming the band image, which is a region other than the contact region in the orbiting body and lacks a region in which the protruding portion of the image overlaps in one direction.

The image forming apparatus according to claim 3 is the image forming apparatus according to claim 1 or 2, wherein the forming portion is a portion in the width direction of the orbiting body at the time of transferring an edgeless image to a medium. The band image is formed so that the amount of toner in the band image and the amount of toner in the protruding portion at each portion in the width direction of the peripheral body have a predetermined ratio.

The image forming apparatus according to claim 4 is a transfer device that orbits in one direction to form an image to be transferred to a medium, and a transfer that transfers the image to the medium by sandwiching the medium between the orbiting bodies while rotating. When the edgeless image is transferred to the medium, the peripheral part forms an image protruding from the contact area of the medium, and the part and the removing part that come into contact with the transfer part and remove the band image attached to the transfer part. A forming portion that forms the band image in a region other than the contact region of the orbiting body and in a region in which the protruding portion of the image overlaps and does not overlap in the one direction, and is in the width direction of the orbiting body. The toner amount of the band image in the non-overlapping region in each portion and the toner amount of the band image in the overlapping region added to the toner amount of the protruding portion in each portion in the width direction of the orbiting body are , A forming portion for forming the band image is provided so as to have a predetermined ratio.

The image forming apparatus according to claim 5 has an orbiting body that orbits in one direction, holds and conveys a medium, a removing unit that comes into contact with the orbiting body and removes an image attached to the orbiting body, and a medium. At the time of transferring the rimless image, an image protruding from the holding area of the medium in the orbiting body is formed and the image is transferred to the medium and the orbiting body, and the area other than the holding area in the orbiting body is the one direction. A forming portion for forming an image to be removed by the removing portion is provided in a region other than the region where the protruding portions of the protruding image overlap.

The image forming apparatus according to claim 1 displays a band image from one end side to the other end side in the width direction of the orbiting body in a region other than the contact area of the medium in the orbiting body when the borderless image is transferred to the medium. Compared with the image forming apparatus to be formed, poor image removal by the removing portion is suppressed.

The image forming apparatus according to claim 2 displays a band image from one end side to the other end side in the width direction of the orbiting body in a region other than the contact area of the medium in the orbiting body when the borderless image is transferred to the medium. Compared with the image forming apparatus to be formed, poor image removal by the removing portion is suppressed.

In the image forming apparatus according to claim 3, the toner amount of the band image in each portion in the width direction of the orbiting body and the toner amount of the protruding portion in each portion in the width direction of the orbiting body satisfy a predetermined ratio. Poor image removal by the removing unit is suppressed as compared with the case without it.

The image forming apparatus according to claim 4 does not form a band image in a region other than the contact region of the medium in the orbiting body and in which the protruding portion of the image overlaps in one direction when the borderless image is transferred to the medium. Compared with the image forming apparatus, poor image removal by the removing unit is suppressed.

The image forming apparatus according to claim 5 has a band in a region that overlaps the toner amount of the band image in the non-overlapping region in each portion in the width direction of the orbiter and the toner amount in the protruding portion in each portion in the width direction of the orbiter. Compared with the case where the toner amount to which the toner amount of the image is added does not satisfy the predetermined ratio, the image removal defect by the removing portion is suppressed.

It is a schematic (front view) of the image forming apparatus of 1st Embodiment. It is a schematic diagram which shows the medium contact area and the medium non-contact area in the transfer belt which comprises the image forming apparatus of 1st Embodiment. It is a schematic diagram which shows an example of the image of the medium contact area formed on the transfer belt, and the band image of a medium non-contact area when image formation is performed in a normal mode by using the image forming apparatus of 1st Embodiment. .. A schematic diagram showing an example of an image of a medium contact area and a band image of a medium non-contact area formed on a transfer belt when image formation is performed in a borderless mode using the image forming apparatus of the first embodiment. is there. When image formation is performed in the borderless mode using the image forming apparatus of the first embodiment, a schematic showing another example of an image of the medium contact area and a band image of the medium non-contact area formed on the transfer belt. It is a figure. When image formation is performed in the borderless mode using the image forming apparatus of the first embodiment, a schematic showing another example of the image of the medium contact area and the band image of the medium non-contact area formed on the transfer belt. It is a figure. When image formation is performed in the borderless mode using the image forming apparatus of the first embodiment, a schematic showing another example of an image of the medium contact area and a band image of the medium non-contact area formed on the transfer belt. It is a figure. When image formation is performed in the borderless mode using the image forming apparatus of the first embodiment, a schematic showing another example of an image of the medium contact area and a band image of the medium non-contact area formed on the transfer belt. It is a figure. It is a schematic diagram which shows an example of the image of the medium contact area and the band image of a medium non-contact area formed on the transfer belt when the image forming apparatus of a comparative form is used for rimless image formation. A schematic diagram showing an example of an image of a medium contact area and a band image of a medium non-contact area formed on a transfer belt when image formation is performed in a borderless mode using the image forming apparatus of the second embodiment. is there. When edgeless image formation is performed using the image forming apparatus of the modified example (first modified example), an example of an image of the medium contact area and a band image of the medium non-contact area formed on the transfer belt is shown. It is a schematic diagram. When edgeless image formation is performed using the image forming apparatus of the modified example (second modified example), an example of an image of the medium contact area and a band image of the medium non-contact area formed on the transfer belt is shown. It is a schematic diagram. It is a schematic (front view) of the image forming apparatus of a modification (third modification).

≪Overview≫
Two embodiments (first and second embodiments) will be illustrated and described with respect to the embodiment (execution) for carrying out the invention.

<< First Embodiment >>
First, the configuration, image forming operation, and effect of the image forming apparatus (see FIG. 1) of the first embodiment will be described with reference to the drawings. In the following description, the direction indicated by the arrow H in FIG. 1 is the direction orthogonal to the device height direction, the device width direction indicated by the arrow W, the device height direction, and the device width direction (direction of arrow D). The device depth direction. Note that FIG. 1 is a front view of the image forming apparatus 10 of the present embodiment.
<Composition>
Hereinafter, the configuration of the image forming apparatus 10 of the present embodiment will be described with reference to FIG. 1 unless otherwise specified. The image forming apparatus 10 is an electrophotographic apparatus including a toner image forming unit 20, a transfer device 30, a conveying device 40, a fixing device 50, and a control unit 60.

[Toner image forming part]
The toner image forming unit 20 has a function of performing each step of charging, exposing, and developing to form a toner image (not shown) held by the transfer belt TB described later on the photoconductors 22Y, 22M, 22C, and 22K described later. Has. Here, the toner image forming portion 20 is an example of the forming portion. The toner image is an example of the image. The toner image forming unit 20 includes monochromatic units 20Y, 20M, 20C, and 20K. Further, the monochromatic units 20Y, 20M, 20C and 20K include photoconductors 22Y, 22M, 22C and 22K, respectively.

[Transfer device]
The transfer device 30 first transferred the toner images formed on the photoconductors 22Y, 22M, 22C, and 22K to the transfer belt TB and held them on the transfer belt TB (that is, formed on the transfer belt TB). ) It has a function of secondarily transferring the toner image to the medium P. The transfer device 30 includes a transfer belt TB, a drive roll 32, a plurality of primary transfer rolls 34, a plurality of driven rolls 36, and a secondary transfer unit 38.

The transfer belt TB has an endless shape, is driven by the driving force of the driving roll 32, and has a function of holding a toner image secondarily transferred (transferred) to the medium P while rotating in the direction of arrow A. Here, the transfer belt TB is an example of an orbiting body. The arrow A direction is an example of one direction. As described above, the toner images developed on the photoconductors 22Y, 22M, 22C, and 22K are primarily transferred to the transfer belt TB by the primary transfer rolls 34 on the transfer belt TB, whereby the medium P is transferred. A toner image that is secondarily transferred to the belt is formed.

The secondary transfer unit 38 includes a secondary transfer roll 38A (hereinafter referred to as a roll 38A), a blade 38B, and a waste toner container 38C. Here, the roll 38A is an example of a transfer unit. The blade 38B is an example of a removing portion.

The roll 38A is arranged on the opposite side of the drive roll 32 with the transfer belt TB interposed therebetween, and forms a nip N1 on the transfer belt TB together with the drive roll 32. Then, the roll 38A is a medium that passes the toner image held by the transfer belt TB through the nip N1 with the drive roll 32 to which the secondary transfer voltage is applied from the power supply (not shown) while rotating around the axis. It is designed to be secondarily transferred to P. That is, the roll 38A has a function of transferring the toner image to the medium P by sandwiching the medium P with the transfer belt TB (the portion wound around the drive roll 32 in the transfer belt TB) while rotating around the axis.

The blade 38B has a function of removing toner, paper dust, and the like floating in the image forming apparatus 10 adhering to the roll 38A. Further, the blade 38B has a function of removing from the roll 38A an image (toner constituting) that is in contact with the roll 38A and adheres to the roll 38A. The waste toner container 38C is arranged so as to surround the blade 38B, and has a function of accommodating the toner removed by the blade 38B. The “image attached to the roll 38A” to be removed from the blade 38B means a band image G2 described later. Further, the blade 38B is in contact with the roll 38A in a range wider than the formation width of the band image G2 (the width in the depth direction of the device in which the band image G2 is formed on the transfer belt TB), which will be described later.

Here, FIG. 2 means a medium contact region R1 (meaning a region in which the medium P contacts, hereinafter referred to as a region R1) and a medium non-contact region R2 (a region in which the medium P does not contact) in the transfer belt TB. Hereafter, it is a schematic diagram showing the region R2). Here, the region R1 is an example of the contact region of the medium in the orbiting body. Further, the region R2 is an example of a region other than the contact region in the orbiting body. The transfer belt TB is endless as described above, but the transfer belt TB in FIG. 2 is shown in a state where it is virtually cut in the width direction at one location in the circumferential direction, but the actual transfer belt TB Are connected by both ends TB1 and TB2 in the circumferential direction. As an example, when performing a transfer operation on a plurality of A4 size media P, the transfer device 30 of the present embodiment has two sheets on the transfer belt TB with the circumferential direction of the transfer belt TB (arrow A direction) as the vertical direction of the medium P. It is possible to form a toner image to be secondarily transferred to the medium P of the minute. Then, the transfer device 30 is set so that a plurality of media P passing through the nip N1 come into contact with two predetermined regions R1 (regions surrounded by each broken line) in the transfer belt TB. The broken line portion of the region R1 is a portion of the nip N1 where the edges of the medium P come into contact with each other.

[Transport device]
The transport device 40 has a function of transporting the medium P housed in the medium accommodating portion 42 through the transport path 46C including the nip N1 and the nip N2 described later, and discharging the medium P to the outside of the device. The transport device 40 includes a delivery roll 46A and a plurality of transport roll pairs 46B.

[Fixing device]
The fixing device 50 has a function of fixing the toner image secondarily transferred (transferred) to the medium P by the transfer device 30 to the medium P. The fixing device 50 includes a heating roll 52 and a pressure roll 54. Then, the fixing device 50 heats the medium P passing through the nip N2 formed by the heating roll 52 and the pressure roll 54 by the heating roll 52, pressurizes the medium P by the heating roll 52 and the pressure roll 54, and pressurizes the medium. The toner image is fixed on P.

[Control unit]
The control unit 60 has a function of controlling each component other than the control unit 60 that constitutes the image forming apparatus 10. The function of the control unit 60 will be described later in the description of the image forming operation.

The above is the description of the configuration of the image forming apparatus 10 of the embodiment.

<Image formation operation>
Next, the image forming operation of the image forming apparatus 10 will be described with reference to the drawings. The image forming apparatus 10 of the present embodiment is adapted to form an image in a normal mode and a borderless mode, which will be described later, according to an image signal transmitted from an external device. Here, the normal mode is a mode in which an image is not formed over the entire edge of the medium P, that is, an image in which the entire edge of the medium P is the edge of the margin portion (hereinafter, an image in the normal mode) is formed. Say. The borderless mode is a mode in which an image in which at least a part of all edges of the medium P is an edge of the image (hereinafter, an image in the borderless mode) is formed. Hereinafter, the image forming operation in the normal mode will be described first, and then the image forming operation in the borderless mode will be described.

[Normal mode]
First, the image forming operation in the normal mode will be described with reference to FIGS. 1 and 3.

When the control unit 60 receives image data for forming an image in the normal mode from an external device (for example, a personal computer), the control unit 60 forms the image data of each color (toner image G1 described later). Image data for). Then, the control unit 60 causes the toner image forming unit 20 to perform each step of charging, exposing, and developing to form a toner image of each color and a band image described later on the photoconductors 22Y, 22M, 22C, and 22K.

Next, the toner image and band image of each color formed on the photoconductors 22Y, 22M, 22C, and 22K are first-order transferred to the transfer belt TB by each primary transfer roll 34. Here, FIG. 3 shows a part of the transfer belt TB in a state where the superimposed toner image G1 of each color and the superimposed band image G2 of each color are formed (on the outer circumference). Since the toner image G1 is a toner image for forming an image in which the entire edge of the medium P is the edge of the margin portion, the toner image G1 protrudes from the inside to the outside of the entire edge (broken line portion) of the region R1 in the transfer belt TB. Formed in the absence. Further, the band image G2 is formed in the region R2 in the transfer belt TB. Specifically, the band image G2 is a portion between two regions R1 in the circumferential direction (arrow A direction) of the transfer belt TB and outside one end of the region R1 in the width direction of the transfer belt TB (transfer). It is formed in a band shape from (one end side of the belt TB) to the outside (the other end side of the transfer belt TB) from the other end of the region R1. When the control unit 60 receives the image data for forming the image in the normal mode, the band image G2 is not the image data included in the image data for forming the image in the normal mode described above, and the control unit 60 receives the image data. It is said that the image data is generated by.

On the other hand, the transport device 40 transports the medium P housed in the medium accommodating portion 42 to the nip N1 at the timing when the portion of the transfer belt TB on which each toner image is first transferred reaches the nip N1.

Next, the roll 38A is a medium that passes the toner image G1 that reaches the nip N1 through the nip N1 with the drive roll 32 to which the secondary transfer voltage is applied from the power supply (not shown) while rotating around the axis. Secondary transfer to P.

Next, the transport device 40 transports the medium P on which the toner images of each color are secondarily transferred toward the nip N2 of the fixing device 50. Then, a toner image of each color is fixed on the medium P passing through the nip N2 (an image is formed on the medium P).

Then, the medium P (the medium P on which the image is formed) on which the toner images of each color are fixed is discharged to the outside of the device by the transport device 40, and the image forming operation in the normal mode is completed.

When the band image G2 (the toner constituting the band image G2) formed in the region R2 of the transfer belt TB reaches the nip N1, a secondary transfer voltage from a power source (not shown) is applied to the drive roll 32. As a result, it adheres to the roll 38A that rotates around the axis. The band image G2 (the toner constituting the roll 38A) adhering to the roll 38A moves around the outer circumference of the roll 38A as the roll 38A rotates, and is removed from the roll 38A by the blade 38B. Then, the toner removed from the roll 38A is stored in the waste toner container 38C. In this case, the blade 38B removes the toner adhering to the roll 38A in the entire range from one end side to the other end side of the edge.

The above is the description of the image forming operation in the normal mode.

[Borderless mode]
Next, the image forming operation in the borderless mode will be described with reference to FIGS. 1 and 4A, 4B, 4C, 4D and 4E.

The image forming operation in the borderless mode differs from the image forming operation in the normal mode in the following two points because the image data received from the external device is different from that in the above-mentioned normal mode. Two different points will be described below.

[Point of primary transfer by toner image forming part]
In the case of the image forming operation in the borderless mode, the image data received by the control unit 60 from the external device is the image data for forming the image in the borderless mode. Here, FIGS. 4A, 4B, 4C, 4D, and 4E show the superimposed toner image G3 of each color and the superimposed band image G4 of each color in the case of the image forming operation in the borderless mode, respectively. Shows a part of the transfer belt TB in which and is formed (on the outer circumference). For example, as shown in FIGS. 4A, 4B, 4C, 4D, and 4E, the toner image G3 is a toner image protruding from the region R1 (a toner in a state of protruding from the inside to the outside of the entire edge of the region R1). Formed as an image). Here, the toner image G3 is an example of an image that protrudes from the contact area of the medium. In the following description, the portion inside the region R1 of the toner image G3 is the region inside G3A, and the portion protruding from the region R1 of the toner image G3 (or the portion formed in the region R2 of the toner image G3) is the protruding portion G3B. That is.

Further, as shown in FIGS. 4A, 4B, 4C, 4D and 4E, the band image G4 is in the circumferential direction of the transfer belt TB with respect to the band image G2 (see FIG. 3) in the normal mode. A partial PG in which the protruding portion G3B overlaps is formed as an image lacking. That is, in the case of the rimless mode (at the time of transferring the rimless image to the medium P), the band image G4 is in the region R2 in the circumferential direction of the transfer belt TB by the toner image forming unit 20 controlled by the control unit 60. It is formed in a region other than the region (region) where the protruding portion G3B of the toner image G3 overlaps.

[Points of secondary transfer by transfer device]
[About the part in the area]
When the region G3A, which is a part of the toner image G3 formed on the transfer belt TB, reaches the nip N1, it is secondarily transferred to the medium P passing through the nip N1 at the same timing. Next, the medium P to which the intra-regional portion G3A is secondarily transferred passes through the nip N2 of the fixing device 50 to fix the intra-regional portion G3A (an image is formed on the medium P). Then, the medium P on which the image is formed is discharged to the outside of the device by the transport device 40, and the image forming operation in the borderless mode is completed.

[About the protruding part and the band image]
When the protruding portion G3B and the band image G4 (the toners constituting the band image G4) formed on the transfer belt TB reach the nip N1, a secondary transfer voltage from a power source (not shown) is applied to the drive roll 32. , Adheres to the roll 38A rotating around the axis. The protruding portion G3B and the band image G4 (the toner constituting the band image G4) adhering to the roll 38A move around the outer circumference of the roll 38A as the roll 38A rotates, and are removed from the roll 38A by the blade 38B. Then, the toner removed from the roll 38A is stored in the waste toner container 38C. In this case, the blade 38B adheres to the roll 38A in the entire range from one end side to the other end side of the edge because the toner constituting the protruding portion G3B and the band image G4 adheres to the roll 38A. Remove the toner.

The above is the description of the image forming operation in the borderless mode. Moreover, the above is the description of the image forming operation of this embodiment.

<Effect>
Next, the effects of the present embodiment will be described with reference to the drawings while comparing the present embodiment with the comparative embodiments described below. When the parts and the like used in the present embodiment are used in the comparative embodiment, the symbols, names, and the like of the parts are used even if they are not shown.

Here, the effect of the present embodiment is a region where the toner image forming portion 20 is the region R2 and the protruding portion G3B of the toner image G3 overlaps in the circumferential direction of the transfer belt TB when the borderless image is transferred to the medium P. This is the effect of forming the band image G4 in a region other than the above. In other words, the effect of the present embodiment is that when the borderless image is transferred to the medium P, the toner image forming portion 20 protrudes in the circumferential direction of the transfer belt TB with respect to the band image G2 formed in the normal mode. This is an effect of forming a band image G4 lacking the partial PG in which the partial G3B overlaps.

The image forming apparatus 10A of the comparative form is equivalent to the band image G2 (see FIG. 3) formed on the transfer belt TB in the normal mode of the present embodiment regardless of the image data received from the external device by the control unit 60. A band image G2 is formed. For example, as shown in FIG. 5, the image forming apparatus 10A of the comparative form forms the band image G2 on the transfer belt TB when the control unit 60 receives the image data for forming the image in the borderless mode. .. The comparative embodiment is the same as that of the present embodiment except for the above points.

When the image forming operation of the borderless image is performed using the image forming apparatus 10A of the comparative form, the protruding portion G3B and the band image G2 (the toners constituting the band image G2) formed on the transfer belt TB rotate around the axis at the nip N1. Adheres to the roll 38A. After that, the protruding portion G3B and the band image G2 (the toner constituting the band image G2) move around the outer circumference of the roll 38A as the roll 38A rotates, and reach the edge of the blade 38B in contact with the roll 38A.

Here, the blade 38B is originally for removing the toner that has reached the edge of the blade 38B in contact with the roll 38A from the roll 38A, but in the case of the comparative form, there is a possibility that the toner removal failure by the blade 38B may occur. There is.

When the borderless image is transferred in the comparative form, the amount of toner of the toner reaching each part in the device depth direction in the blade 38B is the portion that overlaps the protruding portion G3B in the device width direction and the portion that does not overlap the protruding portion G3B. different. Specifically, the amount of toner in the portion overlapping the protruding portion G3B in the device width direction is larger than the amount of toner in the portion not overlapping the protruding portion G3B in the device width direction by the amount of toner in the protruding portion G3B. As a result, in the portion of the blade 38B where the protruding portion G3B overlaps in the device width direction, part or all of the toner adhering to the roll 38A cannot be removed, and poor toner removal by the blade 38B occurs.

On the other hand, when the image forming operation of the borderless image is performed using the image forming apparatus 10 of the present embodiment, the control unit 60 has a borderless mode (FIGS. 4A, 4B) different from the normal mode (see FIG. 3). , FIG. 4C, FIG. 4D and FIG. 4E). Specifically, in the case of the borderless mode in the present embodiment, the band image G4 is a transfer belt with respect to the band image G2 (see the band image G2 in FIGS. 3 and 5) formed in the normal mode. A band image G4 lacking the partial PG in which the protruding portion G3B overlaps in the circumferential direction of the TB is formed (see FIG. 4A as an example). Therefore, in the case of the present embodiment, the amount of toner that reaches the portion of the blade 38B where the protruding portion G3B overlaps in the device width direction reaches the portion of the blade 38B where the protruding portion G3B overlaps in the device width direction. It is less than the amount of toner to be used.

Therefore, according to the image forming apparatus 10 of the present embodiment, when the borderless image is transferred to the medium P, the band image G2 is formed in the region R2 from one end side to the other end side in the width direction of the transfer belt TB. Compared with the configuration, poor removal of the protruding portion G3B and the band image G4 (the toner constituting the band image G4) by the blade 38B is suppressed.

The above is the description of the effect of this embodiment. Further, the above is the description of the first embodiment.
The form) will be described as an example.

<< Second Embodiment >>
Next, the configuration, image forming operation, and effect of the image forming apparatus 10B (see FIG. 6) of the second embodiment will be described with reference to the drawings. When the parts and the like used in the first embodiment are used in the present embodiment, the symbols, names, and the like of the parts are used even if they are not shown.

<Composition and image formation operation>
The image forming apparatus 10B of the present embodiment has a different band image G4 (pattern) when the image forming operation is performed in the borderless mode. When the image forming apparatus 10B of the present embodiment forms the toner image G3 of FIG. 4A by using the image forming apparatus 10 of the first embodiment, for example, the two band images G4 of FIG. 4A (two thirds of FIG. 6). A second band image G4B is formed in a portion between the first band images G4A). That is, the band image G4 of the present embodiment is composed of a first band image G4A corresponding to the band image G4 of the first embodiment and a second band image G4B not found in the band image G4 of the first embodiment. ..

Further, the toner image forming unit 20 of the present embodiment determines the toner amount of the first band image G4A at each portion in the width direction of the transfer belt TB and the toner amount of the protruding portion G3B at each portion in the width direction of the transfer belt TB. The second band image G4B is formed so that the toner amount obtained by adding the toner amount of the second band image G4B has a predetermined ratio. Here, the portion PG in the transfer belt TB on which the protruding portion G3B overlaps in the circumferential direction is an example of the overlapping region. Further, the portion of the transfer belt TB other than the portion PG where the protruding portion G3B overlaps in the circumferential direction is an example of a non-overlapping region. The ratio defined above is set to 1: 1 as an example. That is, in the case of the present embodiment, the toner concentration of the second band image G4B is adjusted according to the toner concentration of the protruding portion G3B of the toner image G3. The present embodiment is the same as the first embodiment except for the above points.

<Effect>
In the case of the first embodiment, as shown in FIGS. 4A, 4B, 4C, 4D and 4E, the band image G4 is not formed on the partial PG in which the protruding portion G3B overlaps in the circumferential direction in the transfer belt TB. Further, in the case of the first embodiment, when the toner concentration of each portion of the protruding portion G3B in the width direction of the transfer belt TB is different, the amount of toner of the toner reaching the portion where the protruding portion G3B overlaps in the device width direction of the blade 38B is increased. Not equivalent.

On the other hand, in the toner image forming unit 20 of the present embodiment, the toner amount of the first band image G4A and the toner amount of the protruding portion G3B at each portion in the width direction of the transfer belt TB are set to the toner amount of the second band image G4B. The second band image G4B is formed so that the toner amount to which the toner amount is added has a predetermined ratio. Therefore, when the edgeless image is formed by using the image forming apparatus 10B of the present embodiment, the blade 38B with respect to the roll 38A is compared with the case where the borderless image is formed by using the image forming apparatus 10 of the first embodiment. The amount of toner that reaches each part in the width direction of the device at the contact portion can be averaged (the variation in the amount of toner that adheres to the roll 38A can be reduced).

Therefore, the image forming apparatus 10B of the present embodiment is an image forming apparatus that does not form the second band image G4B on the partial PG in which the protruding portion G3B overlaps in the circumferential direction in the transfer belt TB when the rimless image is transferred to the medium P. In comparison, poor removal of toner adhering to the roll 38A by the blade 38B is suppressed. Other effects of this embodiment are the same as those of the first embodiment.

As described above, the present invention has been described with reference to specific embodiments as examples, but the present invention is not limited to the above-described embodiments. The technical scope of the present invention also includes, for example, the following forms.

In each embodiment, it is assumed that the band image G4 in the case of performing the image forming operation in the borderless mode is formed in the portion of the region R2 between two regions R1 in the circumferential direction (arrow A direction) of the transfer belt TB. explained. However, when the borderless image is transferred to the medium P, the band image G4 is formed in a region other than the region where the toner image forming portion 20 is the region R2 and the protruding portion G3B of the toner image G3 overlaps in the circumferential direction of the transfer belt TB. Therefore, the portion where the band image G4 is formed does not have to be the portion between the two regions R1 in the circumferential direction of the transfer belt TB. For example, as in the modified example (first modified example) of FIG. 7 and the modified example (second modified example) of FIG. 8, the portion where the band image G4 is formed is a region of the region R2 in the width direction of the transfer belt TB. It may be a part where R1 is present.

Further, the shape of the band image G4 of each embodiment is exemplified as a rectangular shape when viewed from the thickness direction of the transfer belt TB. However, the shape of the band image G4 does not have to be rectangular. For example, the shape of the band image G4 may be linear, a combination of a plurality of circles, or any other shape.

Further, in the description of the first embodiment, the toner amount of each portion in the width direction of the transfer belt TB in the band image G4 is not particularly specified. However, for example, in each portion of the transfer belt TB in the width direction, the amount of toner in the protruding portion G3B and the amount of toner in the band image G4 are in a predetermined ratio (1: 1 as an example). The toner concentration of G4 may be adjusted. In the case of this modified example, it can be said that poor removal of the protruding portion G3B and the band image G4 (the toner constituting the band image G4) by the blade 38B is suppressed as compared with the case where the predetermined ratio is not satisfied.

Further, the toner image forming unit 20 of the second embodiment has the toner amount of the first band image G4A at each portion in the width direction of the transfer belt TB and the toner amount of the protruding portion G3B at each portion of the transfer belt TB in the width direction. It has been described that the second band image G4B is formed so that the toner amount obtained by adding the toner amount of the second band image G4B to the second band image G4B has a predetermined ratio of 1: 1 as an example. However, setting the defined ratio to 1: 1 is only an example, and may be set to, for example, 9:10, 10:7, or the like. It suffices if the removal failure by the blade 38B that removes the toner from the roll 38A can be suppressed.

Further, the image forming devices 10 and 10B of each embodiment have been described as being so-called intermediate transfer type devices having a transfer belt TB. However, the technical idea of the present invention is that, for example, as in the image forming apparatus 10C of the modified example (third modified example) shown in FIG. 9, the toner image forming portion 20 (an example of the forming portion) to the transport belt TB2 (circling). When the toner image is directly transferred to the medium P transported by the transport mechanism 30A having (another example of the body) to form an edgeless image, the toner image is formed in a region other than the medium holding region (holding region) of the transport belt TB2. It is applied to the case where the image protruding from the holding region and the band image (removal image) are formed and the above protrusion image and the removal image are removed by the blade 38B (an example of the removal portion) in contact with the transport belt TB2. May be good.

10 Image forming device 20 Toner image forming part (example of forming part)
38A secondary transfer roll (example of transfer section)
38B blade (example of removal part)
G3 toner image (an example of an image protruding from the contact area of the medium)
G3B protruding part G4 band image P medium R1 area (media contact area)
R2 area (area other than the contact area of the medium)
TB transfer belt (an example of an orbiting body)
TB2 transport belt (another example of an orbiting body)

Claims (5)

An orbiting body that orbits in one direction and forms an image transferred to a medium,
A transfer unit that transfers an image to the medium by sandwiching the medium with the orbiter while rotating.
A removing portion that comes into contact with the transfer portion and removes a band image attached to the transfer portion,
When the rimless image is transferred to the medium, an image protruding from the contact area of the medium is formed on the orbital body, and the protruding portion of the image overlaps in the one direction in the area other than the contact area of the orbiting body. A forming portion that forms the band image in a region other than the region,
An image forming apparatus equipped with. An orbiting body that orbits in one direction and forms an image transferred to a medium,
A transfer unit that transfers an image to the medium by sandwiching the medium with the orbiter while rotating.
A removing portion that comes into contact with the transfer portion and removes a band image attached to the transfer portion,
When the rimless image is transferred to the medium, an image protruding from the contact area of the medium is formed on the orbital body, and the protruding portion of the image overlaps in the one direction in the area other than the contact area of the orbiting body. The forming part that forms the band image lacking the region,
An image forming apparatus equipped with. When the borderless image is transferred to the medium, the forming portion includes the toner amount of the band image at each portion in the width direction of the orbiting body and the toner amount of the protruding portion at each portion of the width direction of the orbiting body. Form the band image so as to have a predetermined ratio.
The image forming apparatus according to claim 1 or 2. An orbiting body that orbits in one direction and forms an image transferred to a medium,
A transfer unit that transfers an image to the medium by sandwiching the medium with the orbiter while rotating.
A removing portion that comes into contact with the transfer portion and removes a band image attached to the transfer portion,
At the time of transferring the rimless image to the medium, an image protruding from the contact area of the medium is formed on the orbiting body, and the protruding portion of the image overlaps in the one direction in the area other than the contact area of the orbiting body. A forming portion that forms the band image in a region that does not overlap with the region, and the toner amount of the band image in the non-overlapping region at each portion in the width direction of the orbiting body and each of the width directions of the orbiting body. A forming portion that forms the band image and a forming portion that forms the band image so that the toner amount obtained by adding the toner amount of the band image in the overlapping region to the toner amount of the protruding portion at the portion has a predetermined ratio.
An image forming apparatus equipped with. An orbiting body that orbits in one direction, holds and conveys the medium,
A removing portion that comes into contact with the orbiting body and removes an image attached to the orbiting body,
At the time of transferring the rimless image to the medium, an image protruding from the holding area of the medium in the orbiting body is formed and the image is transferred to the medium and the orbiting body, and the area other than the holding area in the orbiting body. A forming portion that forms an image to be removed by the removing portion in a region other than the region where the protruding portion of the protruding image in one direction overlaps, and a forming portion.
An image forming apparatus equipped with.