JP2017009723A - Transfer device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce transfer failure in transfer of a toner image.SOLUTION: There is provided a transfer device comprises a transfer roll 73 that holds a sheet P with an intermediate transfer belt 71 and draws a toner image on the intermediate transfer belt 71 onto the sheet P upon reception of application of a transfer voltage, wherein the transfer roll 73 moves between a first position on the upstream side relative to a direction to convey the sheet P where the transfer roll 73 is indicated by a solid line and a second position on the downstream side relative to the direction to convey the sheet P where the transfer roll 73 is indicated by a broken line, and draws one toner image onto the sheet P at least at both the first position and second position.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transfer device and an image forming apparatus.

  Patent Document 1 discloses an image forming apparatus in which toner remaining on an intermediate transfer member after secondary transfer is charged by a toner charging member and then moved from the intermediate transfer member to an image holding member in a primary transfer unit. Has been.

  Patent Document 2 discloses a device in which a multi-color toner image is primarily transferred onto an intermediate transfer member to perform primary transfer, and primary transfer and secondary transfer are not performed simultaneously.

JP 2011-164535 A JP 09-090777 A

  However, in the conventional apparatus, a transfer defect may occur due to environmental changes, particularly under high temperature and high humidity.

  An object of the present invention is to provide a transfer device and an image forming apparatus in which transfer defects are reduced in transferring a powder image.

Claim 1 is a transfer device for transferring a powder image formed on a moving image carrier, which is a laminated body of powders of a plurality of colors, onto a conveyed sheet,
A transfer member that sandwiches a sheet between the image holding member and receives a transfer voltage to draw a powder image on the image holding member onto the sheet;
The transfer member moves between a relatively upstream first position and a relatively downstream second position in the transport direction of the paper, and at least one powder image is transferred to the first position. The transfer device is characterized in that it is attracted onto the paper both at the position and at the second position.

  According to a second aspect of the present invention, the transfer member draws the powder image onto the paper at the first position, and then moves to the second position, and the powder image is transferred to the second position at the second position. 2. The transfer device according to claim 1, wherein the transfer device draws the powder image again at the position of 1 on the paper.

  According to a third aspect of the present invention, the transfer member starts drawing the powder image on the image carrier onto the paper at the first position, and continues to draw the powder image at the second position. The transfer device according to claim 1, wherein the transfer device moves toward the downstream side in the moving direction.

  According to a fourth aspect of the present invention, an environment sensor that measures the temperature and humidity of the environment, and when the temperature and humidity environment measured by the environment sensor is a low-temperature and low-humidity environment that is equal to or lower than a threshold value, transfer is performed by moving the transfer member. And a control unit that performs control to execute transfer while the position of the transfer member is fixed when the temperature and humidity environment exceeds a threshold value. 2. A transfer apparatus according to item 1.

Claim 5
An image forming unit that forms a powder image by laminating a plurality of color powders on a moving image carrier;
5. A transfer unit comprising the transfer device according to claim 1, wherein the image forming unit transfers a powder image formed on the image holding member onto a conveyed sheet. When,
An image forming apparatus comprising: a fixing unit that fixes a powder image transferred onto a sheet by the transfer unit on the sheet.

  According to the transfer device of the first aspect and the image forming apparatus of the fifth aspect, the occurrence of transfer failure can be suppressed as compared with the case where a transfer member that performs transfer at one fixed position is employed.

  According to the transfer device of the second aspect, the occurrence of transfer failure can be suppressed as compared with the case where the transfer is executed only at the first position or only at the second position.

  According to the transfer device of the third aspect, it is possible to transfer to a long sheet while suppressing the occurrence of transfer failure compared to the case where the transfer is performed only at the two positions of the first position and the second position. It is.

  According to the fourth aspect, compared to the case where the transfer by moving the transfer member is performed regardless of the temperature and humidity environment, it is possible to suppress the occurrence of transfer failure and the useless movement of the transfer member.

1 is a schematic configuration diagram of an image forming apparatus as an embodiment of the present invention. It is a figure which shows an example of the moving mechanism of a transfer roll. It is a schematic block diagram of the image forming apparatus as 2nd Embodiment of this invention. It is a figure which shows an example of the moving mechanism of the transfer roll in 2nd Embodiment shown in FIG.

  Embodiments of the present invention will be described below.

  FIG. 1 is a schematic configuration diagram of an image forming apparatus as an embodiment of the present invention.

The image forming apparatus 1 includes a document reading unit 10, an image forming unit 20, and a paper storage unit 30. The image forming unit 20 includes a transfer device as a first embodiment of the present invention.
The document reading unit 10 is provided with a document feed table 11 on which documents S are stacked. The documents S placed on the document feeding table 11 are sent out one by one, conveyed on a conveyance path 13 by a conveyance roll 12, and an original reading optical system placed under a document reading plate 14 made of transparent glass. 15, characters and images recorded on the conveyed document are read and discharged onto the document discharge table 16.

  The document reading unit 10 has a hinge extending left and right on the back side, and can lift the document feeding table 11 and the document discharging table 16 integrally with the hinge as a rotation center. Under the raised position, the document reading plate 14 spreads. In this document reading section 10, instead of placing the document on the document feed tray 11, only one document is placed on the document reading plate 14 downward, and the document reading optical system 15 moves in the direction of arrow A to move the document. It is also possible to read characters and images from the original on the reading plate 14.

An image signal obtained by the document reading optical system 15 is input to the processing / control circuit 21. The processing / control circuit 21 forms an image based on the input image signal as follows. Further, the processing / control circuit 21 is responsible for operation control of each part of the image forming apparatus 1.
The processing / control circuit 21 also functions as an example of a control unit according to the present invention.
In addition, the sheet storage unit 30 provided at the lower portion of the image forming apparatus 1 stores three sheet supply tables 31_1, 31_2, and 31_3. In these paper feed tables 31_1, 31_2, and 31_3, for example, sheets P having different sizes are stacked in each paper feed table 31_1, 31_2, and 31_3. Each of the paper feed trays 31_1, 31_2, and 31_3 is configured to be pulled out for replenishment of the paper P.

  Of these three paper feed trays 31_1, 31_2, and 31_3, for example, the paper P is fed from a paper feed tray (in this example, the paper feed tray 31_3) that accommodates the paper P having a size that matches the size of the original. Are picked up by the pick-up roll 32, separated one by one by the separating roll 33, the one sheet P is conveyed upward in the direction of arrow B by the conveying roll 34, and the subsequent conveying timing by the standby roll 35 Is adjusted and further conveyed. The conveyance after the standby roll 35 will be described later.

  Further, the image forming unit 20 is provided with a manual sheet feed table 22. The manual paper feed tray 22 is a folding type that opens around its lower end. The manual paper feed tray 22 is opened, a paper is placed thereon, and the paper placed on the manual paper feed tray 22 is indicated by an arrow. It is also possible to send in according to C.

  A central portion of the image forming unit 20 includes a photoconductor 51 that rotates in a direction indicated by an arrow D. Around the photoconductor 51, a charger 52, a developing device 60, a static eliminator 54, and a cleaner 55 are provided. Has been placed. An exposure unit 53 is disposed above the photoconductor 51. A transfer roll 56 is placed at a position where an intermediate transfer belt 71 described later is sandwiched between the photoreceptor 51.

  The photosensitive member 51 has a cylindrical shape, stores electric charges by charging, releases the electric charges by exposure, and holds an electrostatic latent image on the surface thereof.

  The charger 52 charges the surface of the photoconductor 51 to a certain charging potential.

  Further, the image signal is input from the processing / control circuit 21 to the exposure unit 53, and a light beam 531 modulated according to the input image signal is output. This light beam 531 repeats the portion of the surface 51 of the photoconductor 51 rotating in the direction of arrow D that has been charged by the charger 52 in the direction of the axis of rotation of the photoconductor 51 (direction perpendicular to the paper surface of FIG. 1). Scanning is performed to form an electrostatic latent image on the surface of the photoreceptor 51.

  Further, the photosensitive member 51 is scanned by the light beam 531 to form an electrostatic latent image on the surface, and then developed by the developing device 60, so that a toner image is formed on the surface of the photosensitive member 51.

  Here, the developing device 60 according to the present embodiment includes four developing devices 61_1, 61_2, 61_3, 61_4 so as to surround the rotation axis, and the developing devices 61_1 to 61_1 are rotated by rotating in the direction of arrow E. 61_4 is revolved around the rotation axis, and any one of the four developing devices 61_1 to 61_4 (the developing device 61_1 in the state shown in FIG. 1) is placed at a position facing the photoconductor 51. Move. The electrostatic latent image formed on the photoconductor 51 is developed by a developing device facing the photoconductor 51 to form a toner image.

  The four developing devices 61_1 to 61_4 provided in the developing device 60 contain yellow (Y), magenta (M), cyan (C), and black (K) toner for each developing device. Yes. In developing the electrostatic latent image on the photoconductor 51, the developing unit containing the toner of the color used this time is moved to a position facing the photoconductor 51, and the developing unit facing the photoconductor 51 uses the developing unit. Development is performed with the color toner stored in the developing unit.

   The toner image formed on the photoconductor 51 by the development by the developing device is transferred onto the intermediate transfer belt 71 by the action of the transfer roll 56.

  The toner remaining on the photoconductor 51 after the transfer is further removed from the photoconductor 51 by a cleaner 55.

  The intermediate transfer belt 71 is an endless belt that is looped around a plurality of rolls 72 and circulates in the direction of arrow F. In the vicinity of the intermediate transfer belt 71, a transfer roll 73 is disposed at a position sandwiching the conveyance path of the paper P. This transfer roll 73 has a first position indicated by a solid line in FIG. 1 and a first position indicated by a broken line in FIG. 1 downstream of the first position in the paper transport direction (arrow G direction). Move between 2 positions. Here, the transfer roller 73 is in contact with the intermediate transfer belt 71 at two locations, the first position and the second position, and the intermediate transfer belt at an intermediate position between the first position and the second position. It moves away from 71. The transfer roll 73 corresponds to an example of a transfer member referred to in the present invention.

  A cleaner 74 that removes toner remaining on the intermediate transfer belt 71 after transfer by the transfer roll 73 is disposed downstream of the second position indicated by the broken line in FIG. . Similar to the cleaner 767 and the transfer roll 73, the intermediate transfer belt 71 can be contacted and separated.

  When forming an image of a plurality of colors, the transfer roll 73 and the cleaner 76 are separated from the intermediate transfer belt 71, and a toner image of a certain color toner is formed on the photoreceptor 51 and transferred to the intermediate transfer belt 71. This process is repeated for a plurality of developing devices (a plurality of color toners) while rotating the developing device 60, and a plurality of toner images of a plurality of color toners are sequentially transferred onto the intermediate transfer belt 71 so as to overlap each other.

Thereafter, the transfer roll 73 is moved to the first position indicated by the solid line in FIG.
Then, the sheet P is sent out from the standby roll 35 so that the overlapped toner images reach the first position where the transfer roll 73 is placed so that the sheet P also reaches the first position. At one position, a plurality of color toner images on the intermediate transfer belt 71 are transferred onto the paper P by the action of the transfer roll 73.

  Here, the image forming apparatus 1 of the present embodiment is provided with an environment sensor 81 that measures the temperature and humidity environment inside the apparatus. The measured temperature and humidity inside the apparatus obtained by the environmental sensor 81 is input to the processing / control circuit 21. The processing / control circuit 21 executes the following control according to the input temperature / humidity measurement value regarding the transfer of the toner image on the intermediate transfer belt 71 to the paper P. That is, the processing / control unit 21 compares the input temperature / humidity measurement value with a threshold value, and determines whether or not the temperature / humidity environment is lower than the threshold value. If it is determined that the environment is not a low temperature and low humidity environment below the threshold value, the processing / control circuit 21 moves the transfer roll 73 to the first position indicated by the solid line and transports the paper P conveyed to the first position. The toner image on the intermediate transfer belt 71 is transferred onto the paper P by being sandwiched between the intermediate transfer belt 71 and the transfer process is ended only at the first position. The sheet P to which the toner image has been transferred is conveyed together with the intermediate transfer belt 71 in the direction indicated by the arrow G, is further conveyed away from the intermediate transfer belt 71, is heated and pressurized by the fixing device 75, and is subjected to the sheet. An image composed of a fixed toner image is formed on the top. The sheet that has passed through the fixing device 75 is further conveyed in the direction indicated by the arrow H and is discharged onto the sheet discharge table 23.

  On the other hand, if the processing / control circuit 21 determines that the input temperature / humidity measurement value is in a low-temperature / low-humidity environment with a threshold value or less, first, the transfer roll 73 is moved to the first position in the same manner as described above. Then, the toner image on the intermediate transfer belt 71 is transferred onto the paper P with the paper P interposed between the intermediate transfer belt 71 and the intermediate transfer belt 71. Then, immediately after the transfer of the toner image to the paper P at the first position is completed, that is, immediately after the rear end of the paper P passes through the first position, the transfer roll 73 is moved forward with respect to the movement of the paper P. Immediately move along the arrow U to the second position indicated by the broken line in the figure. Then, the processing / control circuit 21 causes the transfer roll 73 to sandwich the paper P, which has been advanced to the second position, with the intermediate transfer belt 71 again to perform the transfer process again.

  In a low temperature and low humidity environment, transfer defects are likely to occur. Therefore, in this embodiment, in a low-temperature and low-humidity environment, the transfer process is performed twice in total at both the first position and the second position, thereby preventing the occurrence of transfer failure. When the transfer process is performed at both the first position and the second position, the toner image transferred to the paper P is thereafter transferred to the fixing device 75 as in the case where the transfer process is performed only at the first position. Is fixed on the paper P by heating and pressurizing, and an image composed of a fixed toner image is formed on the paper P. The sheet that has passed through the fixing device 75 is further conveyed in the direction indicated by the arrow H and is discharged onto the sheet discharge table 23.

  After the transfer process, the transfer roll 73 moves to a position separated from the intermediate transfer belt 71 and stands by.

  Further, at the timing of transferring onto the paper P, the cleaner 76 also moves so as to come into contact with the intermediate transfer belt 71, and the toner remaining on the intermediate transfer belt 71 after the transfer by the transfer roll 73 is removed by the cleaner 76. The intermediate transfer belt 71 is removed.

  The image forming apparatus 1 is an apparatus capable of forming images on both sides of the paper P. When images are formed on both sides of the sheet P, the sheet P on which the image is formed only on the first side of the sheet P is discharged on the sheet discharge table 23 in the same manner as described above. By switching, it is conveyed by the conveyance roll 37 in the direction indicated by the arrow I. Thereafter, the conveyance direction is reversed in the direction indicated by the arrow J, and is guided in the direction indicated by the arrow K by the other guide member 38 and is conveyed by the conveyance roll 39 to reach the standby roll 35.

  Thereafter, in the same manner as described above, an image is formed on the second surface of the paper P this time. The paper P on which images are formed on both sides in this way is then discharged onto the paper discharge table 23.

  FIG. 2 is a diagram illustrating an example of a transfer roll moving mechanism. Here, the structure of one end of the transfer roll is shown.

  The transfer roll 73 is supported at its both ends (only one end is shown in FIG. 2) by a support member 90 so as to be movable. Specifically, a long hole 91 bent in an arc shape is formed in the indicating member 90, and the shaft 731 of the transfer roll 73 passes through the long hole 91, whereby the transfer roll 73 is supported by the support member. 90. One end of the long hole 91 corresponds to the first position indicated by the solid line in FIG. 1 and the other end corresponds to the second position indicated by the broken line in FIG. It corresponds to. Further, a pinion gear 95 (the gear teeth are not shown) is supported on a portion of the shaft 731 of the transfer roll 73 that has passed through the long hole 91. However, the shaft 731 of the transfer roll 73 is configured to freely rotate with respect to the pinion gear 95.

  Further, the support member 90 is provided with a rack 92, and the pinion gear 95 is engaged with the rack 92. Here, the teeth of the rack 92 that mesh with the pinion gear 95 are not shown. The rack 92 is also formed in an arc shape having the same shape as the long hole 91. Here, a drive gear 96 (tooth is not shown) that meshes with the pinion gear 95 is also provided. The drive gear 96 is fixed to the shaft 961 and rotates together with the shaft 961.

Here, the shaft 731 of the transfer roll 73 is rotated by receiving a driving force from a first motor (not shown). Since the shaft 731 of the transfer roll 73 is free to rotate with respect to the pinion gear 95, the transfer roll 73 rotates without rotating the pinion gear 95 when the first motor rotates. Therefore, the position of the transfer roll 73 does not move depending on the rotation of the first motor. When the transfer roll 73 is moved to the first position or the second position, the transfer roll 73 is pressed against the intermediate transfer belt 71 to receive a driving force from the first motor, and rotates at the same surface speed as the movement speed of the intermediate transfer belt 71. To do. Note that when the configuration in which the transfer roll 73 is driven and rotated by receiving the driving force from the intermediate transfer belt 71 is employed, the first motor is unnecessary, and the transfer roll 73 can freely rotate with respect to the pinion gear 95. It only has to be.
The drive gear 96 rotates by receiving a driving force from a second motor (not shown). When the drive gear 96 rotates, the drive gear 96 drives the pinion gear 95 to rotate the pinion gear 95. The pinion gear 95 is engaged with the rack 92. For this reason, when the pinion gear 95 rotates, the pinion gear 95 takes the transfer roll 73 with the first position (one end of the long hole 91) and the second position (the other end of the long hole 91). Move between. The long hole 91 and the rack 92 are formed in an arc shape because the transfer roll 73 is pressed against the intermediate transfer belt 71 at the first position and the second position, and the first position and the second position are excluded. This is because the transfer roll 73 is separated from the intermediate transfer belt 71 at an intermediate position between them.

  Here, the environmental sensor 81 is provided to measure the temperature and humidity in the apparatus, and when the temperature and humidity environment is equal to or lower than the threshold value, the transfer process is performed twice in total for both the first position and the second position. To do.

  However, the transfer process may always be performed at both the first position and the second position regardless of the temperature and humidity environment. Alternatively, even when the mode is such that the mode for transferring only at the first position and the mode for transferring at both the first position and the second position are switched, the switching condition is the temperature and humidity environment. It is not limited to. For example, as the thickness of the toner image laminated on the intermediate transfer belt 71 is thicker (as the total area ratio of C, M, Y, and K is larger), transfer defects are more likely to occur. The mode may be switched. Alternatively, depending on the type (for example, surface roughness) of the paper P, there is a paper that may cause a transfer failure and a paper that is not. Therefore, the transfer mode may be switched depending on the type of paper P used for transfer. Furthermore, in the mode in which images are formed on both sides of the paper P, a transfer defect occurs when the image is transferred to the second side, rather than when the image is first transferred to the first side. easy. This is because the moisture of the paper P evaporates due to the heating by the fixing device 75 after the transfer to the first surface, and the drying of the paper P proceeds. For this reason, during the transfer to the second surface after the drying has progressed This is because a transfer defect tends to occur. Therefore, the transfer mode may be switched between the transfer to the first surface and the transfer to the second surface in the mode in which images are formed on both sides of the paper P. Alternatively, the transfer mode may be switched by combining some of these conditions.

  FIG. 3 is a schematic configuration diagram of an image forming apparatus as a second embodiment of the present invention. Here, the elements corresponding to the elements of the image forming apparatus as the first embodiment shown in FIG. 1 have the same reference numerals as those in FIG. Differences will be described. The image forming apparatus shown in FIG. 3 includes the transfer apparatus according to the second embodiment of the present invention.

  In the case of the image forming apparatus according to the first embodiment shown in FIG. 1, the transfer roll 73 moves to the second position after the first transfer process at the first position shown by the solid line in FIG. The transfer process is performed. For this reason, the length in the transport direction of the paper P is shorter than the distance between the first position and the second position, and the transfer roll 73 moves from the first position to the second position from that distance. Must be shorter than the distance obtained by subtracting the distance traveled by the paper P within the time required for.

  On the other hand, in the case of the image forming apparatus of the second embodiment shown in FIG. 3, the restriction on the length in the paper transport direction is relaxed compared to the image forming apparatus shown in FIG.

  In the case of the image forming apparatus according to the second embodiment shown in FIG. 3, the transfer roll 73 is shown by a broken line from the first position shown by a solid line in FIG. 3 while the sheet P is sandwiched between the transfer roll 73 and the intermediate transfer belt 71. It moves in the direction of arrow V to the second position shown. During this movement, the backing roll 72a facing the transfer roll 73 with the intermediate transfer belt 71 interposed therebetween also moves together with the movement of the transfer roll 73. Then, the transfer roll 73 starts the transfer process at the first position, continues the transfer process while moving toward the second position, and ends the transfer process when it reaches the second position. During transfer, the transfer roller 73 moves from a position separated from the intermediate transfer belt 71 to a first position indicated by a solid line in FIG. 3 and is pressed against the intermediate transfer belt 71. When one sheet P is taken out from one of the three sheet feeding tables 31_1, 31_2, and 31_3 and conveyed, and the leading edge of the sheet P in the conveying direction reaches the first position, the sheet P moves in the direction of the arrow V. Start moving.

  Here, the intermediate transfer belt 71 and the paper P move at the same prescribed speed, but the transfer roll 73 and the backing roll 72a move at a speed slower than the prescribed speed. The transfer roll 73 and the backing roll 72a rotate at a rotational speed corresponding to the difference, and thereby move without rubbing between the paper P and the intermediate transfer belt 71. Then, the transfer roll 73 and the backing roll 72a reach the second position at the timing when the trailing edge in the transport direction of the paper P being transported reaches the second position. In this case, as compared with the case where the transfer roll 73 is fixedly arranged at the first position, a transfer process is performed for each region of the paper P over time, thereby preventing a transfer failure.

  Here, it has been described that the transfer roll 73 reaches the second position at the timing when the trailing edge of the paper P reaches the second position. In this way, regardless of the length in the transport direction of the paper P, the moving speed of the transfer roll 73 is always such that the transfer roll 73 reaches the second position when the trailing edge of the paper P reaches the second position. May be adjusted. However, in this case, it is necessary to adjust the rotation speed of the transfer roll 73 according to the length of the paper. Alternatively, only for the longest sheet P, the timing at which the trailing edge of the sheet P reaches the second position of the transfer roll 73 is matched. The rotation speed may be constant.

  In the second embodiment, the transfer mode includes a mode for fixing the transfer roll 73 at the first position and a mode for moving from the first position to the second position. You may switch by conditions and other conditions.

  FIG. 4 is a view showing an example of a moving mechanism of the transfer roll 73 in the second embodiment shown in FIG. FIG. 4 also shows the structure of one end of the transfer roll, as in FIG. In FIG. 4, the components corresponding to the components of the moving mechanism of FIG. 2 are given the same reference numerals even if there are differences in shape, etc. The differences will be described.

  The support member 90 shown in FIG. 4 is provided with a long hole 91 extending horizontally, and the shaft 731 of the transfer roll 73 passes through the long hole 91 extending horizontally. For this reason, the rack 92 is also formed on a flat plate extending horizontally. With this structure, even when the transfer roll 73 is moving, the transfer roll 73 is kept pressed against the intermediate transfer belt 71 or the paper P. In the case of the moving mechanism of FIG. 2 described above, if the transfer roll 73 is moved to an intermediate position between the first position and the second position, the transfer roll 73 is separated from the intermediate transfer belt 71. On the other hand, in the moving mechanism shown in FIG. 4, even if the transfer roll 73 is moved, the transfer roll 73 remains in contact with the intermediate transfer belt 71. Therefore, in the case of the moving mechanism shown in FIG. By this vertical movement mechanism, the transfer roll 73 contacts and separates from the intermediate transfer belt 71.

  The backing roll 72a on the back side of the intermediate transfer belt 71 is also moved in synchronization with the transfer roll 73 by a moving mechanism similar to the moving mechanism shown in FIG.

  Here, an example in which the present invention is applied to an image forming apparatus provided with a so-called rotary type developing device has been described, but a so-called tandem type image forming in which a plurality of developing devices are arranged along an intermediate transfer belt is described. The present invention may be applied to an apparatus or the like.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Original reading part 20 Image forming part 60 Developing device 61_1, 61_2, 61_3, 61_4 Developing device 81 Environmental sensor 90 Support member 91 Long hole 92 Rack 95 Pinion gear 96 Drive gear 731 and 961 Axis

Claims (5)

A transfer device for transferring a powder image formed of a laminate of powders of a plurality of colors formed on a moving image carrier onto a conveyed paper,
A transfer member that sandwiches a sheet between the image holding member and receives a transfer voltage to draw a powder image on the image holding member onto the sheet;
The transfer member moves between a relatively upstream first position and a relatively downstream second position in the transport direction of the paper, and at least one powder image is transferred to the first position. A transfer apparatus that draws on the sheet at both the position and the second position.   The transfer member draws the powder image onto the paper at the first position and then moves to the second position, where the powder image is powdered at the first position. The transfer apparatus according to claim 1, wherein the transfer apparatus draws the body image again on the paper.   The transfer member starts drawing the powder image on the image carrier onto the paper at the first position, and moves toward the second position while continuing to draw the powder image. The transfer device according to claim 1, wherein the transfer device moves to the downstream side in the direction.   An environment sensor that measures the temperature and humidity of the environment, and when the temperature and humidity environment measured by the environment sensor is a low temperature and low humidity environment that is equal to or lower than a threshold value, the transfer member is moved to perform transfer, and the temperature and humidity environment 4. The transfer according to claim 1, further comprising: a control unit that performs control to execute transfer while the position of the transfer member is fixed when the value exceeds a threshold value. 5. apparatus. An image forming unit that forms a powder image by laminating a plurality of color powders on a moving image carrier;
5. A transfer unit comprising the transfer device according to claim 1, wherein the transfer unit transfers the powder image formed on the image carrier by the image forming unit onto the conveyed paper. When,
An image forming apparatus comprising: a fixing unit configured to fix the powder image transferred onto the sheet by the transfer unit.

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