JP7020194B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

In Patent Document 1, a nip portion is formed in contact with an image carrier, and a voltage is applied between the image carrier and the image carrier to transfer a toner image on the image carrier onto a recording medium. A transfer member having an elastic body layer and a high resistance skin layer coated on the elastic body layer is described.

Japanese Patent Application Laid-Open No. 2003-76154

At the transfer position where the image is transferred from the image holder to the recording medium, the frictional force generated between the image holder and the recording medium may change, and the posture of the recording medium may be disturbed. In such a case, in the configuration in which the recording medium is wound around the image holder, the contact on the upstream side in the rotation direction of the image holder in the contact region where the image holder and the recording medium are in contact with each other. At the edge, the recording medium moves slightly with respect to the peripheral surface of the image holder, causing speed fluctuations in the recording medium. Due to this speed fluctuation, the peripheral surface of the image holder and the image rub against each other, and a defect occurs in the image transferred from the image holder to the recording medium.

An object of the present invention is to record from an image holder in a configuration in which the winding angle of the recording medium with respect to the image holder can be changed, as compared with the case where the transport speed of the recording medium is always the same regardless of the winding angle. It is to suppress the occurrence of defects in the image transferred to the medium.

The image forming apparatus according to claim 1 of the present invention sandwiches a long recording medium to be conveyed between an image holder that rotates and holds an image on a peripheral surface, and the image holder. A transfer body that transfers the image held by the holder to the recording medium, an angle changing member that changes the winding angle of the recording medium with respect to the image holder, and a winding angle if the winding angle is large. It is characterized by comprising a control unit for controlling the transport speed of the recording medium so as to increase the transport speed of the recording medium as compared with the case where the angle is small.

The image forming apparatus according to claim 2 of the present invention sandwiches a long recording medium to be conveyed between an image holder that rotates and holds an image on a peripheral surface, and the image holder. A transfer body that transfers the image held by the holder to the recording medium, an angle changing member that changes the winding angle of the recording medium with respect to the image holder, and a winding angle if the winding angle is large. By increasing the transport speed of the recording medium as compared with the case where the angle is small, the transport speed of the recording medium is controlled so as to increase the speed difference between the peripheral speed of the image holder and the transport speed of the recording medium. It is characterized in that it is provided with a control unit.

The image forming apparatus according to claim 3 of the present invention comprises, in the image forming apparatus according to claim 1 or 2, a plurality of the image holder and the transfer body arranged side by side in the transport direction of the recording medium. When the recording medium is wound around the image holder, the control unit holds the peripheral speed of the image holder on the most downstream side in the transport direction of the recording medium, and holds the image on the most upstream side. It is characterized in that the peripheral speed of the image holder is controlled so as to be faster than the peripheral speed of the body.

The image forming apparatus according to claim 4 of the present invention is the image forming apparatus according to claim 3, in which when the recording medium is wound around the image holder, the control unit controls the recording medium. It is characterized in that the peripheral speed of the image holder is controlled so as to increase the peripheral speed of the image holder from the upstream side to the downstream side in the transport direction of the image holder.

The image forming apparatus according to claim 5 of the present invention is the image forming apparatus according to claim 4, wherein the control unit has the same speed difference between adjacent image holders in the transport direction of the recording medium. As described above, it is characterized in that the peripheral speed of the image holder is controlled.

The image reading device according to claim 6 of the present invention is the image forming device according to any one of claims 1 to 5, and the sandwiching load for sandwiching the recording medium between the image holder and the transfer body. The control unit controls the load changing member so that when the winding angle is large, the sandwiching load is smaller than when the winding angle is small. It is characterized by that.

The image forming apparatus according to claim 7 of the present invention includes, in the image forming apparatus according to claim 6, a plurality of the image holder and the transfer body side by side in the transport direction of the recording medium, and the recording medium. When is wound around the image holder, the control unit applies a sandwiching load generated between the image holder and the transfer body on the most upstream side in the transport direction of the recording medium. It is characterized in that the load changing member is controlled so as to be larger than the sandwiching load generated between the image holder and the transfer body on the most downstream side.

The image forming apparatus according to claim 8 of the present invention is the image forming apparatus according to claim 7, when the recording medium is wound around the image holder, the control unit controls the recording medium. It is characterized in that the load changing member is controlled so as to increase the sandwiching load from the downstream side to the upstream side in the transport direction of the above.

According to the image forming apparatus of claim 1, in the configuration in which the winding angle of the recording medium with respect to the image holder can be changed, the transport speed of the recording medium is always the same regardless of the winding angle. Therefore, it is possible to suppress the occurrence of defects in the image transferred from the image holder to the recording medium.

According to the image forming apparatus of claim 2, in the configuration in which the winding angle of the recording medium with respect to the image holder can be changed, the transport speed of the recording medium is always the same regardless of the winding angle. Therefore, it is possible to suppress the occurrence of defects in the image transferred from the image holder to the recording medium.

According to the image forming apparatus of claim 3 of the present invention, the peripheral speed of the most downstream image holder and the peripheral speed of the most upstream image holder are the same in the transport direction of the recording medium. Therefore, it is possible to suppress the occurrence of defects in the image transferred from the image holder to the recording medium.

According to the image forming apparatus of claim 4, the image holder has a place where the peripheral speed of the image holder does not change from the downstream side to the upstream side in the transport direction of the recording medium. It is possible to suppress the occurrence of defects in the image transferred from the image to the recording medium.

According to the image forming apparatus of claim 5, it is possible to suppress the occurrence of defects in the image transferred from the image holder to the recording medium as compared with the case where the speed difference between the adjacent image holders is different. Can be done.

According to the image forming apparatus of claim 6, it is possible to suppress the occurrence of defects in the image transferred from the image holder to the recording medium as compared with the case where the sandwiching load is always the same.

According to the image forming apparatus of claim 7 of the present invention, the sandwiching load generated between the most upstream image holder and the transfer body and the sandwiching load generated between the most downstream image holder and the transfer body are generated. Compared with the case where the sandwiching load is the same, it is possible to suppress the occurrence of defects in the image transferred from the image holder to the recording medium.

According to the image forming apparatus of claim 8, in the transport direction of the recording medium, the image holder is transferred to the recording medium as compared with the case where the sandwiching load does not change from the downstream side to the upstream side. It is possible to suppress the occurrence of defects in the transferred image.

(A) (B) (C) It is a block diagram which showed the transfer unit which concerns on 1st Embodiment of this invention. It is a block diagram which showed the transfer unit which concerns on 1st Embodiment of this invention. It is a block diagram which showed the transfer unit which concerns on 1st Embodiment of this invention. It is a block diagram which showed the transfer unit which concerns on 1st Embodiment of this invention. It is a block diagram which showed the image forming part which concerns on 1st Embodiment of this invention. It is a block diagram which showed the image reading apparatus which concerns on 1st Embodiment of this invention. (A) (B) It is a schematic diagram which showed the image formed by using the image reading apparatus which concerns on 1st Embodiment of this invention, and the image forming apparatus which concerns on a comparative embodiment. It is a figure which showed the friction coefficient of the image formed by the image reading apparatus which concerns on 1st Embodiment of this invention in a graph. It is a block diagram which showed the control system by the control part of the image forming apparatus which concerns on 1st Embodiment of this invention. It is a flow diagram which showed the flow of the control part of the image forming apparatus which concerns on 1st Embodiment of this invention. It is a block diagram which showed the transfer unit which concerns on the comparative embodiment with respect to 1st Embodiment of this invention. (A) (B) (C) It is a block diagram which showed the transfer unit which concerns on 2nd Embodiment of this invention. It is a block diagram which showed the image forming part which concerns on 2nd Embodiment of this invention. It is a block diagram which showed the image forming apparatus which concerns on 2nd Embodiment of this invention. It is a block diagram which showed the control system by the control part of the image forming apparatus which concerns on 2nd Embodiment of this invention. It is a block diagram which showed the transfer unit which concerns on the comparative embodiment with respect to the 2nd Embodiment of this invention.

<First Embodiment>
An example of the image forming apparatus according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 11. The arrow H shown in the figure indicates the device vertical direction (vertical direction), the arrow W indicates the device width direction (horizontal direction), and the arrow D indicates the device depth direction (horizontal direction).

(overall structure)
The image forming apparatus 10 uses a liquid type liquid developer G obtained by dispersing powdered toner in volatile oil (carrier liquid), and uses a toner image on continuous paper P as a long recording medium. It is a device that forms. As shown in FIG. 6, the image forming apparatus 10 includes a conveying unit 20 for conveying the continuous paper P and an image processing unit 24 for forming a toner image.

Further, the image forming apparatus 10 includes an oil removing unit 80 for removing oil from the continuous paper P, a fixing device 70 for fixing the toner image on the continuous paper P, and a control unit 100 (see FIG. 9) for controlling each unit. ing.

In this embodiment, as an example, Isopar L (boiling point 184 [° C.]) manufactured by ExxonMobil Co., Ltd. is used as the oil. The details of the configuration of the control unit 100 will be described later.

[Transporting unit 20]
The transport unit 20 is configured to transport the continuous paper P in the direction of arrow A in the figure (hereinafter referred to as “medium transport direction”) at a predetermined constant transport speed, and is continuous with the pair of transport rolls 20A and 20B. It is provided with a transport force applying unit 90 (see FIG. 9) that imparts a transport force to the paper P.

[Image processing unit 24]
The image processing unit 24 includes an image forming unit 26Y that forms a yellow (Y) toner image, an image forming unit 26M that forms a magenta (M) toner image, and an image forming unit that forms a cyan (C) toner image. A portion 26C and an image forming portion 26K for forming a black (K) toner image are provided. The image forming unit 26K, the image forming unit 26C, the image forming unit 26M, and the image forming unit 26Y are arranged side by side in the vertical direction of the device in this order from the upstream side in the medium transport direction.

In the following description, if it is not necessary to make a distinction, the "Y", "M", "C", and "K" at the end of the code are omitted.

As shown in FIG. 5, the image forming unit 26 uses the liquid developer G to form an image forming unit 30 for forming a toner image and a toner image formed by the image forming unit 30 on continuous paper P. It is provided with a transfer unit 32 for transfer. As described above, the liquid developer G used in the present embodiment is a liquid type liquid developer G obtained by dispersing powdered toner in volatile oil. Further, the volatility in the present embodiment means that the volatile content after 24 hours after being left in an open system at 25 ° C. is more than 8% by mass when the flash point is less than 130 [° C.] or 150 [° C.]. do. The flash point is measured by JIS K2265-4 (2007).

[Image forming unit 30]
The image forming unit 30 includes a photoconductor 38 that holds a toner image, a charging member 40 that charges the photoconductor 38, an exposure device 42 that irradiates the photoconductor 38 with exposure light to form an electrostatic latent image, and photosensitivity. It is provided with a developing device 44 that develops an electrostatic latent image of the body 38 as a toner image. Further, the image forming unit 30 includes a recovery device 56 that recovers the liquid developer G remaining on the photoconductor 38 from the photoconductor 38.

-Developer 44-
The developing device 44 includes a developing unit 50 that delivers the liquid developer G to the electrostatic latent image formed on the photoconductor 38, and a supply unit 48 that supplies the liquid developing agent G to the developing unit 50.

The developing unit 50 includes a developing roll 52 that rotates (circulates) around an axis (in the direction of arrow R2), and a charging member 54 that is arranged so as to face the developing roll 52. Further, the developing unit 50 recovers the charging member 68 that charges the toner contained in the liquid developing agent G that remains on the developing roll 52 without being supplied to the photoconductor 38, and the liquid developing agent G that remains on the developing roll 52. It is equipped with a recovery device 58.

A developing voltage is applied to the developing roll 52 by a power source (not shown), and an electrostatic latent image formed on the photoconductor 38 is formed between the developing roll 52 and the photoconductor 38 (nip portion N1). An electric field for developing is formed. Further, an electric field for supplying the liquid developer G from the supply roll 62 to the developing roll 52 is formed between the supply roll 62 (nip portion N2) described later.

The charging member 54 is used to positively charge the toner contained in the liquid developer G as an example. The charging member 54 is arranged so as to face the developing roll 52 on the downstream side with respect to the nip portion N2 and on the upstream side with respect to the nip portion N1 in the rotation direction of the developing roll 52. The charging member 68 is used for negatively charging the toner contained in the liquid developer G remaining on the developing roll 52 as an example. The charging member 68 is arranged so as to face the developing roll 52 on the downstream side with respect to the nip portion N1 and on the upstream side with respect to the recovery device 58 in the rotation direction of the developing roll 52.

In this configuration, the charging member 54 charges the toner contained in the liquid developer G supplied to the developing roll 52 and held by the developing roll 52, and the liquid developer G containing the toner is photosensitive from the developing roll 52. It is passed to the electrostatic latent image formed on the body 38. When the electrostatic latent image is developed as a toner image using the liquid developer G, the oil also transfers to the photoconductor 38. Further, the charging member 68 negatively charges the toner contained in the liquid developer G remaining on the developing roll 52. By charging the toner negatively, the liquid developer G can be easily recovered from the developing roll 52. Then, the recovery device 58 recovers the liquid developer G remaining on the developing roll 52.

The supply unit 48 includes a developer tank 60 that houses the liquid developer G, and a supply roll 62 that pumps the liquid developer G from the developer tank 60 and supplies it to the developing roll 52. Further, the supply unit 48 is charged positively with the blade 64 for adjusting the layer film of the liquid developer G held by the supply roll 62 and the toner contained in the liquid developer G held by the supply roll 62 as an example. It includes a member 66.

In this configuration, the supply roll 62, which rotates in the direction of arrow R3 in the drawing, pumps up the liquid developer G contained in the developer tank 60. Then, the blade 64 adjusts the layer film of the liquid developer G, and the charging member 66 charges the toner contained in the liquid developer G. Further, the liquid developer G pumped up by the supply roll 62 is supplied to the developing roll 52 by the electric field formed between the supply roll 62 and the developing roll 52. As a result, a film (layer) of the liquid developer G is formed on the developing roll 52.

[Transfer unit 32]
The transfer unit 32 includes a holding roll 34 on which the toner image held by the photoconductor 38 is transferred to hold the toner image, and a driving unit 92 (see FIG. 9) that applies a rotational force to the holding roll 34. Further, the transfer unit 32 moves the transfer roll 36 arranged on the opposite side of the holding roll 34 across the continuous paper P and the winding angle at which the continuous paper P is wound around the holding roll 34 by moving the transfer roll 36. The changing member 102 for changing the above is provided. Further, the transfer unit 32 includes an application member 110 (see FIG. 9) that applies a transfer voltage to the transfer roll 36. The details of the configuration of the transfer unit 32 will be described later.

In this configuration, a primary transfer voltage is applied to the holding roll 34 that rotates in the direction of arrow R4 in the figure by a power source (not shown). As a result, an electric field for transferring the toner image of the photoconductor 38 to the holding roll 34 is formed between the holding roll 34 and the photoconductor 38 (nip portion N3). By this electric field, the toner image held by the photoconductor 38 is transferred to the holding roll 34.

Further, a secondary transfer voltage is applied to the transfer roll 36 by the application member 110. As a result, an electric field for transferring the toner image of the holding roll 34 to the continuous paper P is formed between the transfer roll 36 and the holding roll 34. By this electric field, the toner image transferred to the holding roll 34 is transferred to the continuous paper P.

[Oil remover 80]
As shown in FIG. 6, the oil removing unit 80 includes a melting unit 82 for heating the continuous paper P and an oil receiving unit 84 for receiving the oil on the continuous paper P. Further, the oil receiving unit 84 includes a plurality of a pair of heating rolls 86 having a heater inside.

In this configuration, the melting section 82 heats the continuous paper P. Then, the pair of heating rolls 86 sandwich and convey the continuous paper P, so that the heating roll 86 that comes into contact with the image forming surface side of the continuous paper P receives oil from the continuous paper P.

[Fixing device 70]
The fixing device 70 includes a fixing roll 74 in which a heater is arranged inside, and a holding roll 78 in which a continuous paper P is arranged on the opposite side of the fixing roll 74 and a heater is arranged inside.

In this configuration, the toner image is fixed on the continuous paper P by sandwiching and transporting the continuous paper P between the fixing roll 74 heated by the heater and the holding roll 78 heated by the heater.

(Action of the whole composition)
In the image forming apparatus 10, the continuous paper P supplied from the supply apparatus (not shown) is conveyed along the conveying path 28.

Further, as shown in FIG. 6, the photoconductor 38 of the image forming unit 30 of each color rotates, and the photoconductor 38 is charged by the charging member 40. Next, the exposure apparatus 42 exposes the charged photoconductor 38 according to the image data, and forms an electrostatic latent image on the photoconductor 38. Then, the developing device 44 develops this electrostatic latent image and visualizes it as a toner image.

The toner image formed on the rotating photoconductor 38 is primarily transferred to the holding roll 34. The transfer unit 32 transfers the toner image primaryly transferred to the holding roll 34 onto the continuous paper P to be conveyed. At this time, the oil moves to the continuous paper P together with the toner image. This step is performed in the image forming unit 26 of each color, and the toner image in which each color is overlapped is transferred to the continuous paper P.

Further, when the toner image is transferred to the continuous paper P, the oil removing unit 80 moves to the continuous paper P and removes the adhering oil from the continuous paper P. Further, the fixing device 70 fixes the toner image transferred to the continuous paper P to be conveyed.

(Main part composition)
Next, the transfer unit 32 and the control unit 100 will be described. The thickness of the continuous paper P and the thickness of the toner image shown in each figure are described as thick so that the continuous paper P and the toner image can be easily understood.

[Transfer unit 32]
As shown in FIG. 5, the transfer unit 32 sandwiches a holding roll 34 for holding a toner image, a driving unit 92 (see FIG. 9) for applying a rotational force to the holding roll 34, and a continuous paper P. It includes a transfer roll 36 located on the opposite side of 34. Further, the transfer unit 32 includes a changing member 102 that moves the transfer roll 36 to change the winding angle at which the continuous paper P is wound around the holding roll 34, and an application member 110 that applies a transfer voltage to the transfer roll 36 (FIG. FIG. 9) and. The holding roll 34 is an example of an image holder, and the transfer roll 36 is an example of a transfer body.

The changing member 102 moves the pair of rails 104 that guide the rotary shaft 37 of the transfer roll 36 and the rotary shaft 37 along the rail 104 so as to move the transfer roll 36 along the circumferential direction of the holding roll 34. It is equipped with a drive unit 106 (see FIG. 9). The drive unit 106 is configured by using a well-known actuator mechanism or the like. The changing member 102 is an example of an angle changing member.

In this configuration, the changing member 102 moves the rotation axis 37 of the transfer roll 36 along the rail 104 in the circumferential direction of the holding roll 34, as shown in FIGS. 1A, 1B, and 1C. The transfer roll 36 is moved to. Then, the changing member 102 changes the winding angle (θ in the figure) of the continuous paper P with respect to the holding roll 34. In other words, the changing member 102 changes the contact area between the holding roll 34 and the continuous paper P.

Specifically, the control unit 100 (see FIG. 9) controls the drive unit 106 of the change member 102, so that the change member 102 changes the winding angle θ. In the present embodiment, the winding angle θ is changed according to the capacitance of the continuous paper P. Here, the winding angle θ will be described. In the contact region where the holding roll 34 and the continuous paper P are in contact with each other when viewed from the axial direction of the holding roll 34, the contact end on the upstream side in the rotational direction of the holding roll 34 and the center of the holding roll 34 are connected. The line segment is a basic line segment (L10 in the figure). Then, the "winding angle θ" is an angle formed by this basic line segment and the line segment connecting the center of the holding roll 34 and the center of the transfer roll 36 (L11 in the figure). Further, when the continuous paper P is not wound around the holding roll 34, the winding angle θ is 0 [degrees]. In other words, when the continuous paper P is wound around the holding roll 34, the winding angle θ is larger than 0 [degrees].

Hereinafter, the reason why the winding angle θ is changed depending on the paper type of the continuous paper P will be described.

-For continuous paper P with small capacitance-
In the case of continuous paper P having a small capacitance (for example, in a label paper, the capacitance is 1.5 × 10 ^-7 [μF] per 1 [m ² ]), the voltage dividing with respect to the toner decreases during transfer. Therefore, the transfer voltage must be increased. However, a discharge occurs in the gap between the holding roll 34 and the continuous paper P, and the charge of the toner on the holding roll 34 decreases.

Therefore, in the case of continuous paper P having a small capacitance, it is necessary to bring the continuous paper P into contact with the holding roll 34 before the toner image is transferred to the continuous paper P at the transfer position T (suppressing discharge). There is a need to). Therefore, as shown in FIGS. 1 (C) and 4, the winding angle θ is increased. In the present embodiment, in the case of continuous paper P having a small capacitance, the winding angle θ is set to 10 [degrees] as an example. The winding angle θ shown in FIGS. 1 (C) and 4 is exaggerated.

-For continuous paper P with large capacitance-
In the case of continuous paper P having a large capacitance (for example, in a resin film, the capacitance is 1.0 × 10 ^-6 [μF] per 1 [m ² ]), the partial pressure with respect to the toner decreases during transfer. Since it is suppressed, it is not necessary to increase the transfer voltage as in the case of continuous paper P having a small capacitance. As a result, the discharge in the gap between the holding roll 34 and the continuous paper P is suppressed.

Therefore, in the case of continuous paper P having a large capacitance, the winding angle θ is reduced as shown in FIGS. 1 (A) and 2 (A). In the present embodiment, in the case of continuous paper P having a large capacitance, the winding angle θ is set to 0 [degrees] as an example.

-For continuous paper P with medium capacitance-
In the case of continuous paper P having a medium capacitance (for example, coated paper or plain paper, the capacitance is 5 × 10 ^-7 [μF] per 1 [m ² ]), the continuous paper having a large capacitance is continuous. Compared with the case of paper P, the partial pressure with respect to the toner is reduced at the time of transfer, and as compared with the case of continuous paper P having a small capacitance, the decrease in the partial pressure with respect to the toner is suppressed at the time of transfer. Therefore, the transfer voltage must be increased a little. As a result, a discharge occurs in the gap between the holding roll 34 and the continuous paper P, and the charge of the toner on the holding roll 34 is reduced.

Therefore, in the case of continuous paper P having a medium capacitance, it is necessary to bring the continuous paper P into contact with the holding roll 34 even before the toner image is transferred to the continuous paper P at the transfer position T. Therefore, as shown in FIGS. 1B and 3, the winding angle θ is smaller than the winding angle θ when the continuous paper P having a small capacitance is used, and the capacitance is small. It is made larger than the winding angle θ when the continuous paper P having a large value is used. In the present embodiment, in the case of continuous paper P having a medium capacitance, the winding angle θ is set to 5 [degrees] as an example. The winding angle θ shown in FIGS. 1 (B) and 3 is exaggerated.

[Control unit 100]
The control unit 100 controls each unit as shown in FIG. The configuration of the control unit 100 will be described together with the operations described later.

〔others〕
The image forming apparatus 10 includes an input unit 120 (see FIG. 9) for inputting a paper type. In this configuration, the user inputs the paper type of the continuous paper P used for the image forming apparatus 10 to the input unit 120.

(Action)
Next, the operations of the transfer unit 32 and the control unit 100 will be described with reference to the flow chart shown in FIG. In the state before the image forming apparatus 10 is operated, the winding angle θ of the continuous paper P with respect to all the holding rolls 34 is set to 0 [degrees].

When the user inputs the paper type of the continuous paper P to the input unit 120 and the image forming apparatus 10 is operated, each roll is rotated and the continuous paper P is conveyed. In this state, the peripheral speed of the holding roll 34 and the transport speed of the continuous paper P are the same. Then, the control unit 100 obtains the paper type information input to the input unit 120 by the user in step S100 shown in FIG. When the control unit 100 obtains the paper type information, the process proceeds to step S200. Here, the same means that the peripheral speed of the holding roll 34 is within ± 0.5 [%] of the transport speed of the continuous paper P in consideration of the variation in force transmission and the like.

In step S200, the control unit 100 controls the drive unit 106 of the changing member 102 based on the paper type information. As a result, the changing member 102 moves the transfer roll 36 as necessary to change the winding angle θ. In other words, the changing member 102 changes the contact area between the holding roll 34 and the continuous paper P as needed.

Specifically, in the case of continuous paper P (for example, label paper) having a small capacitance, the winding angle θ is set to 10 [degrees] (see FIG. 1 (C)). Further, in the case of continuous paper P (for example, film) having a medium capacitance, the winding angle θ is set to 5 [degrees] (see FIG. 1 (B)). Further, in the case of continuous paper P (for example, a resin film) having a large capacitance, the winding angle θ is maintained at 0 [degrees] without moving the transfer roll 36 (see FIG. 1 (A)). .. If the winding angle θ is changed as necessary, the process proceeds to step 300.

In step 300, the control unit 100 controls the transport force applying unit 90 based on the winding angle θ to change the transport speed of the continuous paper P. In any case, the transport speed of the continuous paper P is equal to or higher than the peripheral speed of the holding roll.

Specifically, the control unit 100 controls the transport force applying unit 90, and when the winding angle θ is large, the transport speed of the continuous paper P is faster than when the winding angle θ is small. do. In other words, when the winding angle θ is large, the control unit 100 increases the transport speed of the continuous paper P with respect to the peripheral speed of the holding roll 34 as compared with the case where the winding angle θ is small.

More specifically, when the continuous paper P having a small capacitance and the winding angle θ is 10 [degrees], the transport speed of the continuous paper P is set to va1, and the continuous paper P having a medium capacitance is wound. Let va2 be the transport speed of the continuous paper P when the angle θ is 5 [degrees]. Further, assuming that the transport speed of the continuous paper P having a large capacitance and the winding angle θ is 0 [degrees] is va3, the relationship of the following equation (1) is related to va1, va2, and va3. It will be established. When the control unit 100 changes the transport speed of the continuous paper P, the process proceeds to step S400.
va1>va2> va3 ... (1)

In step S400, when the continuous paper P is wound around the holding roll 34, the control unit 100 controls each driving unit 92 based on the position where the holding roll 34 is arranged. Then, the control unit 100 increases the peripheral speed of the holding roll 34 from the upstream side to the downstream side in the transport direction of the continuous paper P. In other words, the speed difference between the peripheral speed of the holding roll 34 and the transport speed of the continuous paper P increases from the upstream side to the downstream side. In other words, the control unit 100 slows down the peripheral speed of the holding roll 34 from the downstream side to the upstream side.

Specifically, the peripheral speed of the holding roll 34Y on the most downstream side in the transport direction of the continuous paper P is set to vb1, and the holding roll 34M arranged next to the holding roll 34Y in the transport direction of the continuous paper P. Let vb2 be the peripheral speed of. Further, the peripheral speed of the holding roll 34C arranged next to the holding roll 34M in the transport direction of the continuous paper P is set to vb3, and the peripheral speed of the holding roll 34C arranged next to the holding roll 34C in the transport direction of the continuous paper P is set to vb3. Let vb4 be the peripheral speed of the holding roll 34K arranged in. Then, for vb1, vb2, vb3, and vb4, the relationship of the following equation (2) is established. In this embodiment, the peripheral speeds of the holding roll 34M, the holding roll 34C, and the holding roll 34K are changed.
vb1>vb2>vb3> vb4 ... (2)

Further, the control unit 100 controls each drive unit 92 so that the speed difference between the adjacent holding rolls 34 is the same. Here, the same means that one speed difference is within ± 10 [%] of the other speed difference in consideration of force transmission variation and the like.

On the other hand, when the winding angle θ is 0 [degrees], the control unit 100 maintains a state in which the peripheral speed of the holding roll 34 is the same as the transport speed of the continuous paper P. Specifically, it is assumed that the transport speed of the continuous paper P when the winding angle θ is 0 [degrees] is va3, and the peripheral speed of the holding roll 34 when the winding angle θ is 0 [degrees] is vb10. For va3 and vb10, the relationship of the following equation (3) is established. When the control unit 100 changes the peripheral speed of the holding roll 34 as necessary, the process proceeds to step S500.
va3 = vb10 ... (3)

In step S500, the control unit 100 controls the application member 110 that applies the transfer voltage to the transfer roll 36 based on the paper type information, and applies the transfer voltage to the transfer roll 36.

Specifically, in the case of continuous paper P having a small capacitance, the transfer voltage is increased as compared with the case of continuous paper P having a large capacitance. More specifically, the transfer voltage in the case of continuous paper P having a small capacitance is Vd1, the transfer voltage in the case of continuous paper P having a medium capacitance is Vd2, and the continuous paper P having a large capacitance is set. The transfer voltage in the case of is Vd3. Then, the relationship of the following equation (4) is established for Vd1, Vd2, and Vd3. When a transfer voltage is applied to the transfer roll 36, the process proceeds to step S600.
Vd1>Vd2> Vd3 ... (4)

In step S600, the toner image transferred and held by the holding roll 34 from the photoconductor 38 is transferred to the continuous paper P with the transfer roll 36, and the transferred toner image is discharged from the image forming apparatus 10. This ends a series of operations. When the series of operations is completed, each roll is stopped, and the transfer roll 36 is moved as needed, so that the winding angle θ of the continuous paper P becomes 0 [degrees].

Next, a situation in which the toner image held by the holding roll 34 is transferred to the continuous paper P will be described.

-For continuous paper P with small capacitance-
In the case of continuous paper P having a small capacitance, the winding angle θ of continuous paper P is 10 [degrees] as shown in FIG. Further, the transport speed of the continuous paper P is higher than the peripheral speed of the holding roll 34.

Here, the operation of the transfer unit 32 will be described while comparing with the transfer unit 532 according to the comparative form. First, the configuration of the transfer unit 532, which is different from that of the transfer unit 32, will be described.

In the transfer unit 532, similarly to the transfer unit 32, as shown in FIG. 11, the winding angle θ of the continuous paper P is 10 [degrees]. However, in the transfer unit 532, unlike the transfer unit 32, the transport speed of the continuous paper P is the same as the peripheral speed of the holding roll 34.

Here, when regions having different amounts of toner per unit area are adjacent to each other in the toner image, the frictional force (friction coefficient) generated between the holding roll 34 and the toner image at the transfer position T changes. Then, the posture of the continuous paper P is disturbed at the transfer position T. Then, in the contact region where the holding roll 34 and the continuous paper P are in contact with each other, the continuous paper P is placed on the peripheral surface of the holding roll 34 at the contact end (part M1 in the figure) on the upstream side in the rotation direction of the holding roll 34. On the other hand, the holding roll 34 moves slightly in the circumferential direction, causing speed fluctuations in the continuous paper P. Therefore, the peripheral surface of the holding roll 34 and the toner image may rub against each other, and a defect may occur in the toner image transferred from the holding roll 34 to the continuous paper P.

For reference, when the toner image is not formed on the label paper as the continuous paper P (when the image density is 0 [%]), when the toner image is formed on the label paper with the image density of 50 [%], and when the label is formed. The graph of FIG. 8 shows the friction coefficient with the case where a toner image having an image density of 100 [%] is formed on paper. From this graph, it can be seen that the coefficient of friction when the image density is 0 [%] and the image density is 100 [%] is smaller than the friction coefficient when the image density is 50 [%].

On the other hand, when the continuous paper P is wound around the holding roll 34, the transfer speed of the continuous paper P in the transfer unit 32 is different from that of the peripheral speed of the holding roll 34, unlike the transfer unit 532. Is getting faster. Therefore, when the continuous paper P is wound around the holding roll 34, the tension applied to the continuous paper P when the transfer unit 32 is used is applied to the continuous paper P when the transfer unit 532 is used. It becomes larger than the tension.

Therefore, the degree of speed fluctuation of the continuous paper P generated at the portion M1 shown in FIG. 4 is smaller than that when the transfer unit 532 is used. As a result, it is possible to prevent defects from occurring in the toner image transferred from the holding roll 34 to the continuous paper P.

For reference, the toner images when the toner image was transferred to the continuous paper P using the transfer unit 32 and the case where the toner image was transferred to the continuous paper P using the transfer unit 532 were enlarged and compared. The toner image shown in FIG. 7A is a case where the transfer unit 32 is used, and the toner image shown in FIG. 7B is a case where the transfer unit 532 is used. It can be seen that when the transfer unit 32 is used, the toner dots are not broken, and when the transfer unit 532 is used, the toner dots are broken.

-For continuous paper P with medium capacitance-
In the case of continuous paper P having a medium capacitance, the winding angle θ of continuous paper P is 5 [degrees] as shown in FIG. Further, the transport speed of the continuous paper P is higher than the peripheral speed of the holding roll 34. Further, the speed difference between the transport speed of the continuous paper P and the peripheral speed of the holding roll 34 is smaller than that of the continuous paper P having a small capacitance.

Then, as described above, the posture of the continuous paper P is disturbed at the transfer position T. As a result, in the contact region where the holding roll 34 and the continuous paper P are in contact with each other, the continuous paper P is placed around the holding roll 34 at the contact end (part M2 in the figure) on the upstream side in the rotation direction of the holding roll 34. It slightly moves in the circumferential direction of the holding roll 34 with respect to the surface, and the speed of the continuous paper P fluctuates.

Here, the transport speed of the continuous paper P is higher than the peripheral speed of the holding roll 34. Therefore, the tension applied to the continuous paper P when the transfer unit 32 is used is larger than the tension applied to the continuous paper P when the transfer unit 532 described above is used. Therefore, the degree of speed fluctuation of the continuous paper P generated at the portion M2 shown in FIG. 3 becomes small. As a result, it is possible to prevent defects from occurring in the toner image transferred from the holding roll 34 to the continuous paper P.

The speed difference between the transport speed of the continuous paper P and the peripheral speed of the holding roll 34 is smaller than that of the continuous paper P having a small capacitance. In other words, the tension applied to the continuous paper P in the case of continuous paper P having a medium capacitance is in proportion to the tension applied to the continuous paper P in the case of continuous paper P having a small capacitance. And become smaller.

However, the distance from the transfer position T to the portion M2 in the case of continuous paper P having a medium capacitance is compared with the distance from the transfer position T to the portion M1 in the case of continuous paper P having a small capacitance. short. Therefore, the degree of speed fluctuation of the continuous paper P generated at the portion M2 is smaller than the degree of the speed fluctuation of the continuous paper P generated at the portion M1. As a result, as described above, the tension applied to the continuous paper P is smaller than that of the continuous paper P having a small capacitance, but is the same as that of the continuous paper P having a small capacitance. In addition, defects are suppressed in the toner image transferred from the holding roll 34 to the continuous paper P.

On the other hand, the transport speed of the continuous paper P may be as high as the transport speed in the case of the continuous paper P having a small capacitance. However, in order to reduce the load on the transporting force applying portion 90, the transport speed of the continuous paper P is slower than the transport speed in the case of the continuous paper P having a small capacitance.

-For continuous paper P with large capacitance-
In the case of continuous paper P having a large capacitance, the winding angle θ of continuous paper P is 0 [degrees] as shown in FIG. Further, the transport speed of the continuous paper P is the same as the peripheral speed of the holding roll 34. Therefore, the toner image held on the holding roll 34 is transferred to the continuous paper P by the electric field formed between the transfer roll 36 and the holding roll 34.

Even if the posture of the continuous paper P is disturbed at the transfer position T, the holding roll 34 is in contact with the continuous paper P only at the transfer position T, so that the posture of the continuous paper P is disturbed and the holding roll 34 is held. Defects are unlikely to occur in the toner image transferred from the roll 34 to the continuous paper P.

Further, since it is not necessary to increase the transport speed of the continuous paper P as compared with the peripheral speed of the holding roll 34, the load on the transport force applying portion 90 is reduced.

(summary)
As described above, when the winding angle θ is large, the transport speed of the continuous paper P is increased as compared with the case where the winding angle θ is small. In other words, when the winding angle θ is large, the transport speed of the continuous paper P is increased with respect to the peripheral speed of the holding roll 34 as compared with the case where the winding angle θ is small. In other words, when the winding angle θ is large, the speed difference between the peripheral speed of the holding roll 34 and the transport speed of the continuous paper P is increased as compared with the case where the winding angle θ is small.

Therefore, it is possible to prevent defects from occurring in the toner image transferred from the holding roll 34 to the continuous paper P. In other words, in a configuration in which the winding angle θ of the continuous paper P with respect to the holding roll 34 can be changed, the holding roll 34 is compared with the case where the transport speed of the continuous paper P is always the same regardless of the winding angle θ. Defects are suppressed in the toner image transferred from the continuous paper P to the continuous paper P.

Further, when the continuous paper P is wound around the holding roll 34 (in the case of the continuous paper P having a small capacitance or in the case of the continuous paper P having a medium capacitance), the transport direction of the continuous paper P. In, the peripheral speed of the holding roll 34Y on the most downstream side is made faster than the peripheral speed of the holding roll 34K on the most upstream side. Therefore, the tension of the continuous paper P in contact with each holding roll 34 becomes larger than that in the case where the peripheral speed of the holding roll 34Y and the peripheral speed of the holding roll 34K are the same.

Then, as the tension of the continuous paper P increases, in the contact region where the holding roll 34 and the continuous paper P are in contact with each other, at the contact ends (sites M1 and M2) on the upstream side in the rotational direction of the holding roll 34. The degree of speed fluctuation of the continuous paper P that occurs becomes small. Therefore, it is possible to prevent defects from occurring in the toner image transferred from the holding roll 34 to the continuous paper P. That is, as compared with the case where the peripheral speed of the holding roll 34Y and the peripheral speed of the holding roll 34K are the same, it is possible to suppress the occurrence of defects in the toner image transferred from the holding roll 34 to the continuous paper P.

When the continuous paper P is wound around the holding roll 34, the peripheral speed of the holding roll 34 is increased from the upstream side to the downstream side in the transport direction of the continuous paper P. Therefore, the tension of the continuous paper P in contact with each holding roll 34 becomes stable as compared with the case where the peripheral speed of the holding roll 34 does not change from the downstream side to the upstream side. Therefore, it is possible to suppress the occurrence of defects in the toner image transferred from the holding roll 34 to the continuous paper P, as compared with the case where the peripheral speed of the holding roll 34 does not change from the downstream side to the upstream side. Toner.

When the continuous paper P is wound around the holding roll 34, the peripheral speed of the holding roll 34 is controlled so that the speed difference between the adjacent holding rolls 34 is the same in the transport direction of the continuous paper P. .. Therefore, the tension of the continuous paper P in contact with each holding roll 34 is stable as compared with the case where the speed difference between the adjacent holding rolls 34 is different. Therefore, as compared with the case where the speed difference between the adjacent holding rolls 34 is different, it is possible to suppress the occurrence of defects in the toner image transferred from the holding rolls 34 to the continuous paper P.

<Second Embodiment>
An example of the image forming apparatus according to the second embodiment of the present invention will be described with reference to FIGS. 12 to 16. In addition, about the 2nd Embodiment, the part different from the 1st Embodiment will be mainly described.

(Constitution)
As shown in FIG. 13, the transfer unit 232 of the image forming apparatus 210 of the second embodiment has a pair of changing members 302 that sandwich the continuous paper P between the holding roll 34 and the transfer roll 36 and change the sandwiching load. I have. The changing member 302 is an example of a load changing member.

The pair of changing members 302 are so-called cylinders, and are arranged so that their ends come into contact with the rails 104 arranged at both ends of the transfer roll 36. Then, the changing member 302 keeps the rail 104 close to and separated from the holding roll 34, so that the transfer roll 36 is brought close to and separated from the holding roll 34. As a result, the sandwiching load for sandwiching the continuous paper P between the holding roll 34 and the transfer roll 36 is changed. Further, a control unit 300 (see FIG. 15) provided in the image forming apparatus 210 controls the changing member 302.

(Action)
The control unit 300 controls the changing member 302 based on the winding angle θ to change the sandwiching load (hereinafter referred to as “pinching load”) for sandwiching the continuous paper P between the holding roll 34 and the transfer roll 36.

Specifically, the control unit 300 controls the changing member 302 to reduce the sandwiching load when the winding angle θ is large as compared with the case where the winding angle θ is small. More specifically, when the continuous paper P having a small capacitance and the winding angle θ is 10 [degrees] (see FIG. 12 (C)), the sandwiching load is set to Fa 1, and the continuous paper having a medium capacitance is used. When the winding angle θ is 5 [degrees] in P (see FIG. 12B), the pinching load is Fa2. Further, assuming that the pinching load is Fa3 when the winding angle θ is 0 [degrees] on the continuous paper P having a large capacitance (see FIG. 12 (A)), the following equation (5) is used for Fa1, Fa2, and Fa3. ) Will be established.
Fa3>Fa2> Fa1 ... (5)

Further, when the continuous paper P is wound around the holding roll 34, the control unit 300 controls each changing member 302 based on the position where the holding roll 34 is arranged. Then, the control unit 300 increases the sandwiching load in the transfer unit 232 from the downstream side to the upstream side in the transport direction of the continuous paper P. Specifically, the sandwiching load in the transfer unit 232Y (see FIG. 14) on the most downstream side in the transport direction of the continuous paper P is set to Fb1, and it is arranged next to the transfer unit 232Y in the transport direction of the continuous paper P. Let the sandwiching load in the transferred transfer unit 232M be Fb2. Further, the sandwiching load in the transfer unit 232C arranged next to the transfer unit 232M in the transport direction of the continuous paper P is set to Fb3, and next to the transfer unit 232C in the transport direction of the continuous paper P. The sandwiching load in the transfer unit 232K arranged in the above is Fb4. Then, for Fb1, Fb2, Fb3, and Fb4, the relationship of the following equation (6) is established.
Fb4>Fb3>Fb2> Fb1 ... (6)

Further, the control unit 300 controls the changing member 302 so that the difference in the sandwiching load between the adjacent transfer units 232 is the same. Here, the same means that one pinching load is within ± 10 [%] of the other pinching load in consideration of each variation.

On the other hand, when the winding angle θ is 0 [degrees], the control unit 300 controls the changing member 302 so that the sandwiching loads in the respective transfer units 232 are the same as each other. In other words, the sandwiching loads of the adjacent transfer units 232 are the same.

Next, a situation in which the toner image held by the holding roll 34 is transferred to the continuous paper P will be described.

-For continuous paper P with small capacitance-
In the case of continuous paper P having a small capacitance, the winding angle θ of continuous paper P is 10 [degrees] as shown in FIG. 12 (C). Further, the sandwiching load in the transfer unit 232 is smaller than that in the case where the winding angle θ is 0 [degrees].

Here, the operation of the transfer unit 232 will be described while comparing with the transfer unit 732 according to the comparative form. First, the configuration of the transfer unit 732, which is different from that of the transfer unit 232, will be described.

In the transfer unit 732, similarly to the transfer unit 232, as shown in FIG. 16, the winding angle θ of the continuous paper P is 10 [degrees]. However, in the transfer unit 732, unlike the transfer unit 232, the sandwiching load in the transfer unit 732 is the same as when the winding angle θ is 0 [degrees].

Here, when regions having different amounts of toner per unit area are adjacent to each other in the toner image, the frictional force (friction coefficient) generated between the holding roll 34 and the toner image at the transfer position T changes. Then, at the transfer position T, the posture of the continuous paper P is disturbed, and at the portion M1, the continuous paper P slightly moves in the circumferential direction of the holding roll 34 with respect to the peripheral surface of the holding roll 34, and the continuous paper P Will cause speed fluctuations. Due to this speed fluctuation, the peripheral surface of the holding roll 34 and the toner image may rub against each other, and a defect may occur in the toner image transferred from the holding roll 34 to the continuous paper P.

On the other hand, in the transfer unit 232, unlike the transfer unit 732, the sandwiching load in the transfer unit 232 is smaller than that in the case where the winding angle θ is 0 [degrees]. Therefore, the amount of fluctuation in the frictional force generated between the holding roll 34 and the toner image at the transfer position T becomes small.

Therefore, the speed fluctuation of the continuous paper P generated at the portion M1 shown in FIG. 12C becomes smaller than that when the transfer unit 732 is used. Therefore, it is possible to prevent defects from occurring in the toner image transferred from the holding roll 34 to the continuous paper P.

-For continuous paper P with medium capacitance-
In the case of continuous paper P having a small capacitance, the winding angle θ of continuous paper P is 5 [degrees] as shown in FIG. 12 (B). Further, the sandwiching load in the transfer unit 232 is smaller than that when the winding angle θ is 0 [degrees], and larger than that when the winding angle θ is 10 [degrees].

Then, as described above, the posture of the continuous paper P is disturbed at the transfer position T, and the continuous paper P is placed on the peripheral surface of the holding roll 34 at the portion M2 shown in FIG. 12 (B). It moves slightly in the circumferential direction of the paper, and the speed of the continuous paper P fluctuates.

Here, the sandwiching load in the transfer unit 232 is smaller than that in the case where the winding angle θ is 0 [degrees]. Therefore, the amount of fluctuation of the frictional force generated between the holding roll 34 and the toner image at the transfer position T becomes small. Therefore, since the degree of speed fluctuation of the continuous paper P generated at the portion M2 shown in FIG. 12B becomes small, it is possible to suppress the occurrence of defects in the toner image transferred from the holding roll 34 to the continuous paper P.

The sandwiching load in the transfer unit 232 is larger than that in the case where the winding angle θ is 10 [degrees]. However, the distance from the transfer position T to the portion M2 in the case of continuous paper P having a medium capacitance is compared with the distance from the transfer position T to the portion M1 in the case of continuous paper P having a small capacitance. short. As a result, the degree of speed fluctuation of the continuous paper P generated at the portion M2 becomes smaller than the degree of the speed fluctuation of the continuous paper P generated at the portion M1. Therefore, as described above, the tension applied to the continuous paper P is smaller than that of the continuous paper P having a small capacitance, but is the same as that of the continuous paper P having a small capacitance. In addition, defects are suppressed in the toner image transferred from the holding roll 34 to the continuous paper P.

On the other hand, it is also conceivable to reduce the pinching load in the transfer unit 232 when the winding angle θ is 5 [degrees] to the same as the pinching load in the transfer unit 232 when the winding angle θ is 10 [degrees]. However, the area where the continuous paper P and the holding roll 34 are in contact with each other when the winding angle θ is 5 [degrees] is such that the continuous paper P and the holding roll 34 are in contact with each other when the winding angle θ is 10 [degrees]. It is small compared to the area where it is. Therefore, if the pinching load in the transfer unit 232 when the winding angle θ is 5 [degrees] is reduced to the same as the pinching load in the transfer unit 232 when the winding angle θ is 10 [degrees], transfer defects will occur. It can happen.

-For continuous paper P with large capacitance-
In the case of continuous paper P having a large capacitance, the winding angle θ of continuous paper P is 0 [degrees] as shown in FIG. 12 (A). Further, the sandwiching load in the transfer unit 232 is larger than that in the case where the winding angle θ is larger than 0 [degree].

Therefore, when the area of contact between the continuous paper P and the holding roll 34 when the winding angle θ is 0 [degrees] is larger than the winding angle θ of 0 [degrees], the continuous paper P and the holding roll 34 Even if the area is small compared to the area in contact with the toner image, defects are suppressed in the toner image transferred from the holding roll 34 to the continuous paper P.

The other control by the control unit 300 is the same as the control by the control unit 100 of the first embodiment. Therefore, the other actions of the second embodiment are the same as those of the first embodiment.

(summary)
As described above, when the winding angle θ is large, the sandwiching load is reduced as compared with the case where the winding angle θ is small. Therefore, it is possible to prevent defects from occurring in the toner image transferred from the holding roll 34 to the continuous paper P. In other words, in a configuration in which the winding angle θ of the continuous paper P with respect to the holding roll 34 can be changed, the toner image transferred from the holding roll 34 to the continuous paper P is compared with the case where the sandwiching load is always the same. Defects are suppressed.

When the continuous paper P is wound around the holding roll 34, the sandwiching load of the transfer unit 232K on the most upstream side is the pinching load of the transfer unit 232Y on the most downstream side in the transport direction of the continuous paper P. Make it larger than that. Therefore, the tension of the continuous paper P in contact with the holding rolls 34 is larger than that in the case where the sandwiching load of the transfer unit 232K and the sandwiching load of the transfer unit 232Y are the same.

Then, as the tension of the continuous paper P increases, the degree of speed fluctuation of the continuous paper P generated at the portions M1 and M2 shown in FIG. 12 decreases. Therefore, it is possible to prevent defects from occurring in the toner image transferred from the holding roll 34 to the continuous paper P. That is, as compared with the case where the sandwiching load of the transfer unit 232K and the sandwiching load of the transfer unit 232Y are the same, it is possible to suppress the occurrence of defects in the toner image transferred from the holding roll 34 to the continuous paper P.

Further, when the continuous paper P is wound around the holding roll 34, the sandwiching load of the transfer unit 232 is increased from the downstream side to the upstream side in the transport direction of the continuous paper P. Therefore, the tension of the continuous paper P in contact with each holding roll 34 becomes stable as compared with the case where the sandwiching load of the transfer unit 232 does not change from the downstream side to the upstream side. Therefore, as compared with the case where the sandwiching load of the transfer unit 232 does not change from the downstream side to the upstream side, it is possible to suppress the occurrence of defects in the toner image transferred from the holding roll 34 to the continuous paper P. Toner.

Further, the difference in the sandwiching load between the adjacent transfer units 232 is the same. As a result, the tension of the continuous paper P in contact with the holding rolls 34 is stabilized as compared with the case where the difference in the sandwiching load of the adjacent transfer units 232 is different. Therefore, as compared with the case where the difference in the sandwiching load of the adjacent transfer units 232 is different, it is possible to suppress the occurrence of defects in the toner image transferred from the holding roll 34 to the continuous paper P.

Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments can be taken within the scope of the present invention. Is obvious to those skilled in the art. For example, in the above embodiment, the present configuration is used for the toner image forming apparatus that forms the toner image using the liquid developer G, but the present configuration is used for the image forming apparatus that forms the toner image using the powder developer. May be used.

Further, in the above embodiment, the winding angle is changed according to the capacitance of the continuous paper P, but the winding angle may be changed depending on the surface roughness of the continuous paper P or the like.

Further, in the above embodiment, although the image forming apparatus including the plurality of image forming portions 26 has been described, the image forming apparatus may be provided with one image forming unit.

Further, in the above embodiment, a transfer electric field is formed between the transfer roll 36 and the holding roll 34 by applying a voltage to the transfer roll 36, but by applying a voltage to the holding roll, it becomes a transfer roll. A transfer electric field may be formed between the holding roll and the holding roll.

Further, in the above embodiment, the position of the transfer roll 36 is moved to change the winding angle θ, but the transfer path of the continuous paper P on the upstream side with respect to the transfer roll 36 is changed in the transfer direction of the continuous paper P. Therefore, the winding angle θ may be changed.

Further, in the above embodiment, the winding angle θ is changed to three stages, but it may be two stages or four or more stages.

Further, in the above embodiment, the peripheral speed of the holding roll 34 is changed, but the peripheral speed of all the holding rolls related to the winding angle θ may be the same. However, in this case, the effect of changing the peripheral speed of the holding roll does not work.

Further, in the above embodiment, the toner image is transferred from the holding roll 34 to the continuous paper P, but the toner image may be directly transferred from the photoconductor 38 to the continuous paper P.

Further, in the above embodiment, when the image forming apparatus 10 is operated, each roll is rotated and the continuous paper P is conveyed, but even if the roll is rotated to convey the continuous paper P after setting each parameter. good. This makes it possible to reduce the waste of the continuous paper P.

10 Image forming device 34 Holding roll (an example of an image holding body)
36 Transfer roll (an example of a transfer body)
100 Control unit 102 Changing member (an example of angle changing member)
210 Image forming device 300 Control unit 302 Changing member (example of load changing member)

Claims (8)

An image holder that rotates and holds the image on the peripheral surface,
A transfer body that sandwiches the conveyed long recording medium between the image holder and the image holder and transfers the image held by the image holder to the recording medium.
An angle changing member that changes the winding angle of the recording medium with respect to the image holder, and
When the winding angle is large, a control unit that controls the transport speed of the recording medium so as to increase the transport speed of the recording medium as compared with the case where the winding angle is small,
An image forming apparatus. An image holder that rotates and holds the image on the peripheral surface,
A transfer body that sandwiches the conveyed long recording medium between the image holder and the image holder and transfers the image held by the image holder to the recording medium.
An angle changing member that changes the winding angle of the recording medium with respect to the image holder, and
When the winding angle is large, the transport speed of the recording medium is increased as compared with the case where the winding angle is small, so that the speed difference between the peripheral speed of the image holder and the transport speed of the recording medium is large. A control unit that controls the transport speed of the recording medium,
An image forming apparatus. A plurality of the image holder and the transfer body are provided side by side in the transport direction of the recording medium.
When the recording medium is wound around the image holder, the control unit sets the peripheral speed of the image holder on the most downstream side in the transport direction of the recording medium, and the image on the most upstream side. The image forming apparatus according to claim 1 or 2, wherein the peripheral speed of the image holder is controlled so as to be faster than the peripheral speed of the holder. When the recording medium is wound around the image holder, the control unit increases the peripheral speed of the image holder from the upstream side to the downstream side in the transport direction of the recording medium. The image forming apparatus according to claim 3, wherein the peripheral speed of the image holder is controlled as described above. The image forming apparatus according to claim 4, wherein the control unit controls the peripheral speed of the image holders so that the speed differences between the adjacent image holders are the same in the transport direction of the recording medium. A load changing member for changing the sandwiching load for sandwiching the recording medium between the image holder and the transfer body is provided.
Any one of claims 1 to 5 in which the control unit controls the load changing member when the winding angle is large so as to reduce the sandwiching load as compared with the case where the winding angle is small. The image forming apparatus according to the section. A plurality of the image holder and the transfer body are provided side by side in the transport direction of the recording medium.
When the recording medium is wound around the image holder, the control unit generates sandwiching between the image holder and the transfer body on the most upstream side in the transport direction of the recording medium. The image forming apparatus according to claim 6, wherein the load changing member is controlled so that the load is increased as compared with the sandwiching load generated between the image holder and the transfer body on the most downstream side. When the recording medium is wound around the image holder, the control unit increases the sandwiching load from the downstream side to the upstream side in the transport direction of the recording medium. The image forming apparatus according to claim 7, which controls a load changing member.

Images