JP3835587B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus for re-transferring an image transferred from a photosensitive member to an intermediate transfer member onto a recording medium conveyed in a sandwiched state between the transfer device facing the intermediate transfer member and the intermediate transfer member. The present invention relates to an image forming apparatus that prevents a recording medium from being caught in an intermediate transfer member.
[0002]
[Prior art]
Conventionally, apparatuses for removing a recording medium wound around an intermediate transfer member are known from Japanese Patent Laid-Open Nos. 9-190084 and 10-301401.
[0003]
[Problems to be solved by the invention]
However, such an image forming apparatus detects the winding of the recording medium around the intermediate transfer member with an optical or potential sensor, and forcibly separates the recording medium with a separation claw. Contacting the separation claw with the surface of the body is likely to cause scratches, and there is a problem in that the quality of the image is deteriorated and the life of the intermediate transfer member is affected.
[0004]
Also, since the toner including the ground cover is adhered to the surface of the intermediate transfer member, when the contact of the separation claw is repeated, the toner is scattered in the apparatus due to the adhesion of the toner to the separation claw and the toner is transferred to the recording medium. There is a problem that the image is likely to fall and image defects are likely to occur.
[0005]
SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that peels a recording medium from an intermediate transfer member without using a separation claw.
Another object of the present invention is to provide an image forming apparatus that can easily take out a recording medium peeled from an intermediate transfer member to the outside of the apparatus.
[0006]
[Means for Solving the Problems]
The present invention has a conveying means for conveying the recording medium to the intermediate transfer member side, retransfers the image transferred from the photosensitive member to the intermediate transfer member to the transfer surface of the recording medium, and cooperates with the intermediate transfer member. Then, in an image forming apparatus having a transfer device that conveys the recording medium in a sandwiched state,
A curl correcting means arranged in a recording medium introduction path for guiding the recording medium to the intermediate transfer member side, for correcting the curl so that the transfer surface side of the recording medium is convex toward the intermediate transfer member;
Separating discharge means for removing electricity so that a portion of the recording medium transferred by the transfer device is adjacent to the downstream side of the transfer device so as to be separated from the intermediate transfer member;
Detecting means for detecting the leading end of the recording medium when the recording medium adheres to the surface of the intermediate transfer body and is transported beyond the charge removal area by the separation discharge means;
The gist of the invention is that when the detection unit detects the recording medium, conveyance of the recording medium by the conveyance unit is stopped.
[0007]
The present invention includes a curl correcting unit that is disposed in a recording medium introduction path that guides the recording medium to the intermediate transfer member side and corrects the curl so that the transfer surface side of the recording medium is convex toward the intermediate transfer member side. Yes.
[0008]
This curling correction means imparts curling habits of the recording medium. For example, the curling correcting means includes a pair of elastic rollers and a rigid roller having a diameter smaller than that of the elastic rollers. The curl correction can be performed so that plastic deformation occurs and the intermediate transfer member is convex.
[0009]
For this reason, the curl correction means imparts curling habits so that the recording medium is separated from the intermediate transfer member, thereby resisting the recording medium from being wound around the intermediate transfer member.
The curl correcting means may be provided in the transport path from the recording medium storage location to the registration roller. Even if the curl correcting means has a recording medium transport capability, it is merely a guide means. Also good.
[0010]
It is also an effective means of the present invention that this curl correcting means is also used (shared) as a registration roller.
According to such technical means, no additional curl correcting means is provided, and the number of parts is reduced.
[0011]
In addition, the present invention has separation discharge means that is adjacent to the downstream side of the transfer unit and discharges the portion of the recording medium transferred by the transfer unit so as to be separated from the intermediate transfer member. When the image is transferred to the recording medium, the electrostatic charge between the recording medium and the intermediate transfer member can be reduced by neutralizing the charge charged on the transfer portion.
[0012]
In addition, the present invention includes a detecting unit that detects the leading end portion of the recording medium in the traveling direction when the recording medium adheres to the surface of the intermediate transfer member and is conveyed beyond the charging area by the separation discharge unit, When the detection unit detects the recording medium, the conveyance of the recording medium is stopped, and in this state, the recording medium can be prevented from being caught in the intermediate transfer body even if the intermediate transfer body is rotated by a predetermined amount.
[0013]
According to the first aspect of the present invention, the recording medium can be conveyed by the curl correcting means, and the recording medium is held by the curl correcting means in a state where the curling correcting means stops conveying the recording medium. that the holding force, when said intermediate transfer member by a predetermined amount of rotation, the recording medium is characterized by greater than the conveying force received while electrostatically attracted to the intermediate transfer member surface.
[0014]
According to such a technique, since the curling correction means and the means for suppressing electrostatic attraction by the separation discharge means are provided, the adhesion of the recording medium to the intermediate transfer body is suppressed, and the recording medium adheres to the intermediate transfer body. Even in this case, since the conveyance of the recording medium is stopped, the recording medium is not wound around the intermediate transfer member, and the recording medium can be easily removed from the intermediate transfer member during the jam processing.
[0015]
According to a second aspect of the present invention, when the detection unit detects the recording medium adsorbed to the intermediate transfer member, first, the transfer unit stops applying the transfer voltage, and after a predetermined time, said separation discharging means is configured to stop the application of the separation voltage, characterized by being adapted to stop conveyance of said recording medium by said conveying means.
[0016]
According to such technical means, when the detection means detects the recording medium adsorbed on the intermediate transfer member, before the transfer of the recording medium is stopped, the transfer device first stops applying the transfer voltage, and then In the recording medium, the charge for transfer is not charged, and the portion already transferred is neutralized by the downstream separation discharge means, and the charged portion due to the transfer of the recording medium disappears, and after a predetermined time, the separation discharge By stopping the application of the separation voltage of the means, the electrostatic adsorption force of the recording medium to the intermediate transfer member is suppressed.
[0017]
According to a third aspect of the present invention, there is provided a photoconductor, a charger that charges the photoconductor, a developing device that is disposed downstream of the charger in the rotation direction of the photoconductor , and the photoconductor on the photoconductor. An intermediate transfer member to which a toner image formed by a developing unit is transferred; and a conveying unit that conveys a recording medium to the intermediate transfer member. The image transferred from the photosensitive member to the intermediate transfer member is recorded on the recording medium. An image forming apparatus having a transfer device that re-transfers the toner image to the transfer surface of the recording medium and that conveys the recording medium in a sandwiched state in cooperation with the intermediate transfer member.
A curl correcting means arranged in a recording medium introduction path for guiding the recording medium to the intermediate transfer member side, for correcting the curl so that the transfer surface side of the recording medium is convex toward the intermediate transfer member;
Separating discharge means for removing electricity so that a portion of the recording medium transferred by the transfer device is adjacent to the downstream side of the transfer device so as to be separated from the intermediate transfer member;
Detecting means for detecting the leading end of the recording medium when the recording medium adheres to the surface of the intermediate transfer body and is transported beyond the charge removal area by the separation discharge means;
When the detection unit detects the recording medium, the conveyance unit is configured to stop conveyance of the recording medium,
Further , after stopping the charging bias voltage of the charger, the photosensitive member continues to rotate until the charged portion of the photosensitive member finishes development by the developing device, and the developing operation of the developing device is stopped. characterized by stopping the rotation of the photosensitive member.
[0018]
According to such technical means, after the charging bias voltage of the charger is stopped, the rotation of the photosensitive member is continued until the charged portion of the photosensitive member passes the developing portion, and then the developing operation of the developing device is stopped, and then the photosensitive member is exposed to light. Stop rotating the body. As a result, the carrier does not fly to the charged portion of the photosensitive member during the next printing operation, so that the carrier runs short or the carrier scatters in the machine, and the photosensitive member, intermediate transfer member, fixing roller surface, etc. it is possible to prevent a call hurt.
[0019]
Further, the invention according to claim 4 is configured such that the curl correcting means is capable of conveying a recording medium,
The transfer unit is configured to be able to contact and separate from the intermediate transfer member,
When the detection means detects the recording medium, the transfer device is separated from the intermediate transfer body to release the pressing load on the recording medium,
After the intermediate transfer member is rotated by a predetermined amount in a state where conveyance of the recording medium by the curl correcting means is stopped, the curl correcting means removes the recording medium until at least the end of the recording medium comes off the curl correcting means. It is characterized by being configured to re-carry.
[0020]
According to such technical means, after the adsorbed portion of the recording medium adsorbed to the intermediate transfer member is detected, the recording medium is conveyed by the curl correcting means until the recording medium is detached from the curl correcting means. There is nothing to hold down the recording medium 8, and therefore the operator opens the cover of the apparatus main body, and the recording medium is exposed in a state where the part from the curl correcting means (7a, 7b) to the conveying path 14 is exposed as shown in FIG. 8 can be easily taken out of the apparatus.
[0021]
According to a fourth aspect of the present invention, there is provided cleaning means for removing residual toner on the intermediate transfer body downstream from a position where the detection means detects the recording medium adsorbed on the intermediate transfer body.
When the detection unit detects the recording medium adsorbed on the intermediate transfer body, after the conveyance of the recording medium is stopped, the toner on the surface of the intermediate transfer body is removed by the cleaning unit while the intermediate transfer body is removed. Configuring the body to rotate a predetermined amount is also an effective means of the present invention.
[0022]
According to such technical means, for example, as shown in FIG. 1, when the detection means 11 detects the recording medium 8 adsorbed to the intermediate transfer member 5, the conveyance of the recording medium 8 is stopped by the registration roller pair 7a, 7b. At the same time, the pressing of the recording medium 8 against the intermediate transfer member 5 by the transfer unit 9 is released. The leading edge S1 of the recording medium stops somewhere between the distance L2 between the detecting means 11 and the cleaning means 12 due to a response delay at the time of stopping.
Thereafter, the intermediate transfer member is rotated by a predetermined amount while toner adhering to the surface of the intermediate transfer member 5 is removed by the cleaning means.
[0023]
As a result, the recording medium is separated from the surface of the intermediate transfer member, and is placed on the conveyance path 14 via the one-dot chain line in FIG. 1 and the two-dot chain line. They are transported and placed.
Further, even if the recording medium is adsorbed on the surface of the intermediate transfer member, the adsorbing force becomes weak, and by re-transporting the recording medium, the recording medium is separated from the surface of the intermediate transfer member, and from the one-dot chain line in FIG. It is transported and placed on the transport path 14 via a two-dot chain line as a three-dot chain line.
According to such technical means, when the recording medium is jammed, the recording medium can be easily removed outside the apparatus.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to specific examples unless otherwise specified. Only.
[0025]
FIG. 1 is a cross-sectional view of a main part of an image forming apparatus according to an embodiment of the present invention. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The photosensitive drum 1 is made of amorphous silicon and has a diameter of 80 mm. Around the photosensitive drum 1, along the rotational direction, there are four developing devices 4Y (yellow) including a charger 3, an optical scanning unit 2, and a developer container. 4M (for magenta), 4C (for cyan), 4K (for black), a first static eliminator 13, an intermediate transfer member 5, a cleaning device 6, and a second static eliminator 4.
[0026]
The intermediate transfer member 5 has an intermediate transfer film having a thickness of 50 μm to 5 mm and a volume resistivity of 10 ⁹ Ω · cm to 10 ¹² Ω · cm, and is formed to have a finished product diameter of φ160 mm. The outer periphery is in contact with the body drum 1 with an appropriate nip (about 10 mm) width, and both are configured to be rotatable in the direction of the arrow through a reduction gear train by a main motor (not shown).
[0027]
Around the intermediate transfer member 5, a curl correcting means 7, a transfer roller 9, a separation discharger 10, and an intermediate transfer member 5, which constitute a decurling mechanism with a pair of registration rollers 7 a and 7 b from the upstream side in the conveyance direction of the recording medium 8. Jam detection means (detection means) 11 for detecting the leading end of the attached recording medium and detecting that the recording medium has jammed, and a fur brush cleaner 12 for removing residual toner on the intermediate transfer member 5 are provided. The recording medium 8 is configured to be transportable along a transport path 14 to a fixing device (not shown).
[0028]
The curl correcting means 7 includes an elastic roller 7a having a sponge layer formed on a rigid core shaft, and a rigid roller 7b having a smaller diameter than the elastic roller 7a, and presses the recording medium 8 at a linear pressure of 0.2 kg / cm. As a result, plastic deformation of the recording medium occurs, and curl correction can be performed so as to be convex toward the intermediate transfer member.
[0029]
Then, the curl correcting means 7 is arranged in the recording medium introduction path 15 for guiding the recording medium 8 to the intermediate transfer member 5 side, and the leading end S1 in the traveling direction of the recording medium 8 performs the front curl correction and the intermediate transfer. The recording medium 8 coming in a direction in contact with the outer periphery of the body 5 is conveyed by bending the conveying direction of the recording medium 8 so that the advancing direction front end S1 is directed toward the transfer device 9 when pressed. The curling is applied in the direction opposite to that of the intermediate transfer member, and the recording medium is conveyed at such a timing that the image transferred on the intermediate transfer member is transferred to the recording medium in synchronization with the tip position. It is configured.
[0030]
The transfer roller 9 has a volume resistivity of 10 ⁷ Ω · cm to 10 ⁹ Ω · cm, an elastic body thickness of 3 to 10 mm, and a finished body diameter of φ20 to φ30 mm. Although retracted to an initial position separated from the outer periphery, the registration roller pair 7a, 7b is in press contact with the outer periphery of the intermediate transfer body 5 before conveying the recording medium 8, and is opposite to the transfer surface of the recording medium 8. A predetermined voltage is applied to this surface, and when the transfer of the image onto the recording medium is completed or the conveyance of the recording medium 8 is stopped as described later even before the transfer is completed, the initial position can be returned.
[0031]
The separation discharger 10 is arranged downstream of the transfer roller 9 and electrically neutralizes the transfer medium 9 by, for example, positively charging the negatively charged recording medium 8. As a result, the electrostatic attractive force acting on the transfer portion of the intermediate transfer member 5 and the recording medium 8 can be suppressed.
[0032]
The jam detection means (detection means) 11 is for observing the end portion of the central transfer body 5 in the axial center direction. More specifically, when the recording medium 8 is attached to the intermediate transfer body 5 and rotated, The recording medium is arranged so that it can be detected.
This detection means 11 has a light emitting portion and a light receiving portion, detects a recording medium by detecting the presence or absence of reflected light based on a difference in reflectance from the surface of the intermediate transfer body, and a control not shown in the figure. It is sent to the device.
Then, when the leading edge of the recording medium adhering to the surface of the intermediate transfer member 5 is separated, it is separated from the surface of the intermediate transfer member 5 by a predetermined distance (for example, 5 mm or more) so as to be caught by the detection means 11 and not bend. It is desirable to arrange them.
[0033]
The fur brush cleaner 12 is disposed on the downstream side adjacent to the jam detecting means (detecting means) 11, and this cleaner adsorbs residual toner on the intermediate transfer member by the electric force of the brush to clean the intermediate transfer member. To do. In the apparatus, the toner on the brush is adsorbed by a collecting roller (not shown), and the adsorbed toner is scraped off by a cleaning blade (not shown).
[0034]
Since the present embodiment is configured as described above, at the time of printing, the photosensitive drum 1 is charged by the charger 3 for each color in the order of the developing units 4K, 4C, 4M, and 4Y. The images developed by the exposure and developing devices 4K, 4C, 4M, and 4Y are transferred to the intermediate transfer member 5, transferred to a recording medium 8 conveyed from a paper feeding cassette (not shown) by a transfer roller 9, and then fixed by a fixing device (not shown). Heat and press to fix and discharge.
[0035]
Next, the operation in the jam state in which the recording medium 8 is attracted to the surface of the intermediate transfer member 5 will be described in detail with reference to FIGS.
The photosensitive drum 1 shown in FIG. 1 develops 4Y from the developing device 4K through 4C and 4M for each rotation, and is sequentially laminated and transferred onto the intermediate transfer member to form the multicolor formed on the surface of the intermediate transfer member 5. The toner image approaches the secondary transfer position T2 by the rotation of the intermediate transfer body 5, and the registration roller pairs 7a and 7b are synchronized with the leading end of the multicolor toner image approaching the secondary transfer position T2. While the recording medium 8 is conveyed, the transfer roller 9 presses the surface of the intermediate transfer body 5 in synchronization with this.
[0036]
The transfer roller 9 applies a negative transfer voltage from the back surface of the recording medium 8 to secondarily transfer the multicolor toner image to the recording medium 8.
The multi-color toner image is neutralized electrically by discharging positive charges by a separation discharger 10 arranged downstream of the transfer roller 9. As a result, the electrostatic attractive force acting on the transfer portions of the intermediate transfer body 5 and the recording medium 8 can be suppressed.
Thereafter, the recording medium 8 is moved to the left in FIG. 1, and the image is fixed by a fixing device (not shown).
[0037]
In FIG. 2, when the recording medium 8 secondarily transferred by the transfer roller 9 is conveyed while adsorbed on the surface of the intermediate transfer body 5, it is detected by the detecting means 11 (20), and the transfer roller 9 is transferred to the transfer voltage. Is stopped (21), and the pressure on the recording medium 8 is released to return to the initial position.
[0038]
From the position Q1 at the downstream end of the recording medium 8 that is substantially pressed against the recording medium 8 by the transfer roller 9, the recording medium 8 that is negatively charged by the transfer roller 9 of the separation discharger 10 substantially. When the position where the transfer portion is positively charged is Q2 and the conveyance speed of the recording medium is V, when t1 = distance (Q1 to Q2) / V has elapsed (22), the separation discharge is stopped ( 23).
[0039]
As a result, the transfer portion of the negatively charged recording medium 8 is electrically neutralized by discharging a positive charge, and the electrostatic attractive force acting on the transfer portion of the intermediate transfer body 5 and the recording medium 8 is suppressed. Can do.
[0040]
If the rotation of the registration rollers 7a and 7b is stopped and the conveyance of the recording medium 8 is stopped with the intermediate transfer body 5 and the photosensitive drum 1 being rotated (24), the recording medium 8 is overrun. The tip is positioned between the center point P2 of the cleaning means 12 and the observation point P1 of the detection means 11 as indicated by S1 and stops.
[0041]
Thereafter, the toner image on the surface of the intermediate transfer member is removed by the cleaning means, and the intermediate transfer member is rotated by a predetermined amount.
In the present embodiment, when the conveyance speed of the recording medium is V, the peripheral length of the intermediate transfer member is L0, and the distance L2 between the detection means 11 and the cleaning means 12 is t2 = (L0 + L2) / V When the time has elapsed (25), the operation of the cleaning means 12 is stopped (26).
[0042]
On the other hand, when the recording medium 8 is conveyed while adsorbed to the surface of the intermediate transfer member 5 and detected by the detection means 11 (20), charging of the photosensitive drum 1 is stopped (32).
After the charging bias voltage of the charger is stopped, until the charged portion of the photosensitive member finishes development, that is, the recording medium conveyance speed is V, and the position from the charging position to the fourth developing device 4Y is set. When the distance up to M is M, when t4 = M / V has elapsed (33), development is stopped (34).
[0043]
After stopping the charging bias voltage of the charging device, the rotation of the photosensitive member is continued until the charged portion of the photosensitive member finishes developing, thereby stopping the developing operation of the developing device and stopping the rotation of the photosensitive member. As a result, the carrier does not fly to the charged portion of the photoreceptor.
[0044]
When the cleaning means 12 is stopped and the intermediate transfer member and the photosensitive drum are stopped (27) by stopping the main motor, as a result, the recording medium 8 is separated from the surface of the intermediate transfer member 5, and one point in FIG. The recording medium is placed on the transport path 14 via the two-dot chain line from the chain line, and the recording medium is transported again (28).
[0045]
Assuming that the conveyance speed of the recording medium is V, the length of one recording medium is L, and the length of the conveyance path to the registration roller pairs 7a and 7b and the detecting means 11 is L1, t4 = (L−L1) After the transfer of only / V (29), the conveyance of the recording medium 8 by the registration roller pair 7a, 7b is stopped (30), so that the rear end of the recording medium 8 is disengaged from the registration roller pair 7a, 7b. They are transported and placed.
Further, even if the recording medium is adsorbed on the surface of the intermediate transfer member, the adsorbing force becomes weak, and by re-transporting the recording medium, the recording medium is separated from the surface of the intermediate transfer member, and from the one-dot chain line in FIG. It is transported and placed on the transport path 14 via a two-dot chain line as a three-dot chain line.
[0046]
Then, after the adsorbed portion of the recording medium adsorbed on the intermediate transfer member is peeled off from the intermediate transfer member, the curl correcting means removes the recording medium until the recording medium is removed from the curl correcting means (registration roller pair 7a, 7b). Since the recording medium is conveyed, the recording medium stops before the leading edge reaches the fixing device, and there is nothing to hold down the recording medium 8 in that state. Therefore, the operator opens the cover of the apparatus main body, as shown in FIG. The recording medium 8 can be easily taken out of the apparatus in a state where the portion from the curl correcting means (7a, 7b) to the conveyance path 14 is exposed, and jammed paper processing (31) can be performed.
[0047]
As described in detail above, in the present embodiment, when the recording medium is jammed, the recording medium is easily separated from the surface of the intermediate transfer member, and the toner on the intermediate transfer member is removed by the cleaning means. The next recording medium can be prevented from being soiled.
[0048]
In addition, since the present embodiment has a curl correcting means that can also be used as a registration roller, the recording medium is provided with a curling characteristic so as to be separated from the intermediate transfer body. Can be prevented from being wound around.
[0049]
In addition, since the present embodiment has separation discharge means that is adjacent to the downstream side of the transfer roller and discharges the portion of the recording medium transferred by the transfer roller so as to be separated from the intermediate transfer member. When the image is transferred to the recording medium, the electrostatic charge between the recording medium and the intermediate transfer member can be reduced by neutralizing the charge charged on the transfer portion.
[0050]
In addition, the present embodiment includes a detecting unit that detects the leading end of the recording medium in the traveling direction when the recording medium adheres to the surface of the intermediate transfer member and is transported beyond the discharge area by the separating discharge unit. When the detection unit detects the recording medium, the conveyance of the recording medium by the curl correction unit is stopped, and in this state, the intermediate transfer member is rotated by a predetermined amount to separate the recording medium from the intermediate transfer member. can do.
[0051]
When the detection unit detects the recording medium adsorbed to the intermediate transfer member, the transfer unit first stops applying the transfer voltage, and after a predetermined time, the separation discharge unit Is stopped, and the conveyance of the recording medium by the curl correction means is stopped. Therefore, when the detection means detects the recording medium adsorbed to the intermediate transfer member, the conveyance of the recording medium is performed. First, the transfer device stops applying the transfer voltage before the transfer is stopped. After that, the charge for transfer to the recording medium is not charged, and the already transferred portion is charged by the separation discharge means on the downstream side. Is neutralized and the charged portion due to transfer of the recording medium disappears. After a predetermined time, the application of the separation voltage of the separation discharge means is stopped, thereby suppressing the electrostatic adsorption force of the recording medium to the intermediate transfer member. .
[0052]
Further, the present embodiment includes a charger that charges the photoconductor, and a developing device that is disposed downstream of the charger in the rotation direction of the photoconductor,
After the charging bias voltage of the charger is stopped, the developing operation of the developing device is stopped by continuing the rotational driving of the photosensitive member until the charged portion of the photosensitive member finishes developing, and the rotation of the photosensitive member is stopped. Since the driving is stopped, after the charging bias voltage of the charger is stopped, the photosensitive member is continuously rotated until the charged portion of the photosensitive member finishes development, and the developing operation of the developing device is continued. By stopping the rotation of the photosensitive member, the carrier does not fly to the charged portion of the photosensitive member.
[0053]
Further, in this embodiment, the transfer device is configured to be able to contact and separate from the intermediate transfer member, and when the detection unit detects the recording medium, the transfer device is separated from the intermediate transfer member. And releasing the pressing load on the recording medium, and after rotating the intermediate transfer body by a predetermined amount in a state where the conveyance of the recording medium by the curl correcting means is stopped, at least the end of the recording medium is Since the recording medium is re-conveyed by the curl correcting means until the curl correcting means is removed, the recording medium adsorbed to the intermediate transfer member is removed from the intermediate transfer member after the adsorbed portion is peeled off from the intermediate transfer member. Since the recording medium is transported by the curl correcting means until it is released, the recording medium stops before the leading edge reaches the fixing device, and in this state, there is nothing that holds down the recording medium 8. Therefore, the operator opens the cover of the apparatus main body, and as shown in FIG. 1, the operator can easily take out the recording medium 8 outside the apparatus in a state where the part from the curl correcting means (7a, 7b) to the conveyance path 14 is exposed. Can do.
[0054]
【The invention's effect】
As described above in detail, the present invention does not forcibly separate the recording medium from the intermediate transfer member by the separation claw, but by bringing the separation claw into contact with the surface of the intermediate transfer member on which the image is to be laminated, No scratches are generated on the surface of the transfer body, and the quality of the image is not deteriorated and the life of the intermediate transfer body is not affected.
[0055]
Further, when the recording medium is jammed, the recording medium is easily separated from the surface of the intermediate transfer body and the toner on the intermediate transfer body is cleaned by the cleaning means, so that the next recording medium can be prevented from being contaminated.
[0056]
Further, after the adsorbed portion of the recording medium adsorbed on the intermediate transfer member is peeled off from the intermediate transfer member, the recording medium is conveyed by the curl correcting means until the recording medium is detached from the curl correcting means. The front end stops before reaching the fixing device, and there is nothing to hold the recording medium in that state. Therefore, the operator can easily remove the recording medium from the apparatus by opening the cover of the apparatus main body.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an entire image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating jam detection of a recording medium.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Photosensitive drum 5 Intermediate transfer body 7 Curl correction means (registration roller pair 7a, 7b)
9 Transfer device (transfer roller)
10 Separation discharge means 11 Detection means

Claims (6)

It has a conveying means for conveying the recording medium to the intermediate transfer member side, retransfers the image transferred from the photosensitive member to the intermediate transfer member to the transfer surface of the recording medium, and sandwiches it in cooperation with the intermediate transfer member In an image forming apparatus having a transfer device that conveys the recording medium in a state,
A curl correcting means arranged in a recording medium introduction path for guiding the recording medium to the intermediate transfer member side, for correcting the curl so that the transfer surface side of the recording medium is convex toward the intermediate transfer member;
Separating discharge means for removing electricity so that a portion of the recording medium transferred by the transfer device is adjacent to the downstream side of the transfer device so as to be separated from the intermediate transfer member;
Detecting means for detecting the leading end of the recording medium when the recording medium adheres to the surface of the intermediate transfer body and is transported beyond the charge removal area by the separation discharge means;
The curl correcting unit is configured to be able to transport a recording medium, and the intermediate transfer member has a holding force for holding the recording medium by the curl correcting unit in a state where the curl correcting unit stops transporting the recording medium. When the recording medium is rotated by a predetermined amount, the recording medium is set to be larger than the conveying force received while being electrostatically attracted to the intermediate transfer member surface ,
Wherein when the detecting means detects the recording medium, the conveying means by images forming device you characterized by being configured to stop conveyance of the recording medium. It has a conveying means for conveying the recording medium to the intermediate transfer member side, retransfers the image transferred from the photosensitive member to the intermediate transfer member to the transfer surface of the recording medium, and sandwiches it in cooperation with the intermediate transfer member In an image forming apparatus having a transfer device that conveys the recording medium in a state,
A curl correcting means arranged in a recording medium introduction path for guiding the recording medium to the intermediate transfer member side, for correcting the curl so that the transfer surface side of the recording medium is convex toward the intermediate transfer member;
Separating discharge means for removing electricity so that a portion of the recording medium transferred by the transfer device is adjacent to the downstream side of the transfer device so as to be separated from the intermediate transfer member;
Detecting means for detecting the leading end of the recording medium when the recording medium adheres to the surface of the intermediate transfer body and is transported beyond the charge removal area by the separation discharge means;
When the detection unit detects the recording medium adsorbed to the intermediate transfer member, the transfer unit first stops applying the transfer voltage, and after a predetermined time, the separation discharge unit applies the separation voltage. the is stopped, images forming device you characterized by being configured to stop conveyance of said recording medium by said conveying means. A photoconductor, a charger for charging the photoconductor, a developing device disposed downstream of the charger in the rotation direction of the photoconductor, and a toner image formed by the developer on the photoconductor is transferred. An intermediate transfer member that is transferred to the intermediate transfer member, and a transfer unit that transfers the recording medium to the intermediate transfer member. The image transferred from the photosensitive member to the intermediate transfer member is transferred to the transfer surface of the recording medium. In addition, in an image forming apparatus having a transfer device that conveys the recording medium in a sandwiched state in cooperation with the intermediate transfer member,
A curl correcting means arranged in a recording medium introduction path for guiding the recording medium to the intermediate transfer member side, for correcting the curl so that the transfer surface side of the recording medium is convex toward the intermediate transfer member;
Separating discharge means for removing electricity so that a portion of the recording medium transferred by the transfer device is adjacent to the downstream side of the transfer device so as to be separated from the intermediate transfer member;
Detecting means for detecting the leading end of the recording medium when the recording medium adheres to the surface of the intermediate transfer body and is transported beyond the charge removal area by the separation discharge means;
When the detection unit detects the recording medium, the conveyance unit is configured to stop conveyance of the recording medium,
Further , after stopping the charging bias voltage of the charger, the photosensitive member continues to rotate until the charged portion of the photosensitive member finishes development by the developing device, and the developing operation of the developing device is stopped. the photoreceptor images forming device characterized by stopping the rotation of. It has a conveying means for conveying the recording medium to the intermediate transfer member side, retransfers the image transferred from the photosensitive member to the intermediate transfer member to the transfer surface of the recording medium, and sandwiches it in cooperation with the intermediate transfer member In an image forming apparatus having a transfer device that conveys the recording medium in a state,
A curl correcting means arranged in a recording medium introduction path for guiding the recording medium to the intermediate transfer member side, for correcting the curl so that the transfer surface side of the recording medium is convex toward the intermediate transfer member;
Separating discharge means for removing electricity so that a portion of the recording medium transferred by the transfer device is adjacent to the downstream side of the transfer device so as to be separated from the intermediate transfer member;
Detecting means for detecting the leading end of the recording medium when the recording medium adheres to the surface of the intermediate transfer body and is transported beyond the charge removal area by the separation discharge means;
When the detection unit detects the recording medium, the conveyance unit is configured to stop conveyance of the recording medium,
The curl correcting means is configured to be able to transport a recording medium,
The transfer unit is configured to be able to contact and separate from the intermediate transfer member,
When the detection means detects the recording medium, the transfer device is separated from the intermediate transfer body to release the pressing load on the recording medium,
After the intermediate transfer member is rotated by a predetermined amount in a state where conveyance of the recording medium by the curl correcting means is stopped, the curl correcting means removes the recording medium until at least the end of the recording medium comes off the curl correcting means. images forming device you characterized by being configured to re-conveyance. A cleaning unit for removing residual toner on the intermediate transfer member on a downstream side of a position where the detection unit detects the recording medium adsorbed on the intermediate transfer member;
When the detection unit detects the recording medium adsorbed on the intermediate transfer body, after the conveyance of the recording medium is stopped, the toner on the surface of the intermediate transfer body is removed by the cleaning unit while the intermediate transfer body is removed. 5. The image forming apparatus according to claim 4, wherein the body is rotated by a predetermined amount. 6. The image forming apparatus according to claim 1, wherein the curl correcting means is shared with a registration roller.

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