JP3002267B2 - Recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

Relates record apparatus that can be formed an image freely the present invention in front and back sides of the transfer paper BACKGROUND OF THE INVENTION Laser printers and more particularly, applied to a digital copying machine or the like <br/> obtained Ru on record apparatus.

[0002]

2. Description of the Related Art An optical writing means capable of writing an image on a writing object as a normal image or a mirror image, a rotatable photoconductor as the optical writing object, and a latent image written on the photoconductor by the optical writing means. Developing means for visualizing the toner image as a primary toner image, a belt as an intermediate transfer member which is disposed opposite to the photoreceptor, is supported by a belt unit and allows transfer paper to pass between the photoreceptors, and the primary toner image Primary image transfer means for transferring the primary toner image to a transfer paper, intermediate transfer means for transferring the primary toner image to a belt as a secondary toner image, and secondary toner image for transferring the secondary toner image to a transfer paper transfer means, that have a record device has been proposed.

[0003] This record device, the selected front and back sides of the transfer paper, and is capable both of image recording of both sides.

In the case of surface recording, a primary recorded toner image on a photoreceptor is transferred onto a transfer paper surface on a belt by an intermediate transfer means to obtain a surface recorded image.

[0005] In the case of backside recording, the primary toner image on the photoreceptor is temporarily transferred to a belt as a secondary toner image using an intermediate transfer means, and then the secondary toner image on the belt is transferred to the belt. The image is transferred to the back surface of the transfer paper by the secondary toner transfer means to obtain a back-side recorded image.

In the case of double-sided recording, first, a secondary toner image is transferred onto a belt in the same manner as in the above-described backside recording, and then a primary toner image is formed on a photoconductor in the same manner as in the above-described frontside recording.
The primary toner image and the secondary toner image are simultaneously transferred to the front side and the back side of the transfer paper sent on the belt, thereby obtaining a double-sided image.

[0007] Each of these recordings can be performed using only one color toner. In addition, by using toners of different colors, a color superimposed toner image is obtained on a photoreceptor or a belt to obtain a multicolor or full color image. Recording is also possible. That is, as a recording mode, a front side recording in which a toner image is formed on the front side of a transfer sheet by single color or color superposition, a back side recording in which a toner image is formed on the back side of the transfer sheet, a combination of the front side recording mode and the back side recording mode Double-sided recording performed in such a manner is possible. In addition,
Color overlay means full color or multicolor.

Accordingly, by appropriately selecting these recording modes, it is possible to freely form a recorded image on the front or back surface of the transfer paper. It can be composed.

[0009] In record device that written, 2 primary toner image transferring or or primary toner image to the transfer paper to the belt
It is necessary to keep the belt in contact with the photoconductor when transferring as the next toner image, but it is not necessary to keep the belt in contact with the photoconductor when transferring the secondary toner image to transfer paper.

In this connection, for example, Japanese Patent Application Laid-Open No.
Japanese Patent Application Laid-Open No. 115235 discloses a technique in which the transfer belt is separated from the photoconductor at the time of non-transfer, in order to avoid excess toner on the photoconductor from adhering to the transfer belt, which is not the intermediate transfer body referred to in the above proposed technique. Have been. JP-A-59-104673 discloses a technique in which an intermediate transfer member is brought into contact with a photosensitive member only during transfer.

[0011]

In the proposed technique, as described above, it is necessary for the transfer of the primary toner image to bring the belt into contact with the photosensitive member in order to perform the transfer satisfactorily. On the other hand, the transfer of the secondary toner image is not from the photoconductor, so there is no need to keep the belt in contact with the photoconductor. There is a problem that interference causes a positional shift and causes abnormal transfer such as transfer blur, transfer omission, transfer blur, and the like. In this regard, there is no disclosure in the above publications regarding separation of the photoconductor from the belt during transfer of the secondary toner image.

The present invention relates to a recording apparatus capable of freely recording on both the front side and the back side of a transfer sheet. When recording on the back side of the transfer sheet, the transfer sheet becomes unstable on the intermediate transfer member during the conveyance process for the back side transfer. It is an object of the present invention to provide a recording apparatus that can prevent abnormal transfer by preventing the occurrence of abnormal transfer.

[0013]

In order to attain the above object, an intermediate transfer member having a belt-like shape, which is configured to be able to freely contact and separate from a photosensitive member and has a substantially horizontal belt surface, is provided with the intermediate transfer member interposed therebetween. The one on the photoconductor is provided at a position facing the photoconductor.
A primary toner image transfer unit having a voltage application function of transferring a next toner image to the intermediate transfer member as a secondary toner image; and a primary toner image transfer unit that is provided at a position downstream of the primary toner image transfer unit in the transfer paper transport direction. A secondary toner image transfer means for transferring a secondary toner image on the intermediate transfer member to transfer paper; in the case of surface recording, the intermediate transfer member is brought into contact with the photosensitive member while the intermediate transfer member is in contact with the photosensitive member; A state in which the primary toner image on the photoconductor is transferred to the front surface of the transfer paper by passing a transfer paper between the body and the photoconductor, and in the case of backside recording, the intermediate transfer body is brought into contact with the photoconductor. After the primary toner image on the photoconductor is transferred to the intermediate transfer member as a secondary toner image, the intermediate transfer member is separated from the photoconductor and transfer paper is placed on the intermediate transfer member. At the position of the secondary toner image transfer means. Of a recording apparatus which can be transferred to the transfer sheet back surface of the secondary toner image, when the rear-side recording, after the completion of transfer to the intermediate transfer member of the primary toner image,
In the process of placing a transfer paper on the intermediate transfer body and moving it together with the intermediate transfer body toward the secondary toner image transfer means,
The primary toner image transfer unit is set in a functional state.

[0014]

[0015]

[0016]

By placing the primary toner image transfer means in a functional state, an electrostatic attraction force for attracting the transfer paper to the intermediate transfer body acts to enhance the holding of the transfer paper on the intermediate transfer body.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing specific embodiments of the present invention,
The outline of the prerequisite surface recording apparatus will be described with reference to FIG.

[0018] This record device, selected by, front and back sides of the transfer paper, and roughly in what also possible any image recording these duplex, a document reading unit, the optical writing unit,
It is divided into an image forming unit, a fixing unit, a sheet feeding unit, and a transfer sheet conveying unit.

The document reading means moves in the scanning direction A integrally with the contact glass 1 for placing the document G, the pressure plate 2 covering them, the illumination lamp 3 for illuminating the document G, and the illumination lamp 3. First mirror M1, this first mirror M
It comprises a second mirror M2 that moves in the scanning direction A in conjunction with 1, a reduction lens 4, a color CCD image sensor 5, and a scanner controller (not shown).

With this configuration, when the original G is scanned, the original image information is read by the color CCD image sensor 5.
Is converted into an electric signal corresponding to the original image of blue, green, red, and black, and is stored in the storage means.

The electric signal is further processed by an image processing unit (not shown) and sent to an optical writing unit.

The optical writing means includes a semiconductor laser, means for applying the electric signal to a driving current of the semiconductor laser, and a rotating mirror 6 for deflecting and scanning a beam from the semiconductor laser.
, An imaging optical system 7 including an fθ lens, and a third mirror M3 for guiding this beam to a drum-shaped photoconductor 8 to be written.

Since this optical writing means stores the image information in the form of a digital signal, it can be written as a normal image on the photosensitive member 8 by changing the writing order or the like, or can be written as a mirror image.

Next, the image forming means includes a photosensitive member 8 rotated in the direction of the arrow, and a developing means 9 for visualizing the latent image written on the photosensitive member 8 by the optical writing means as a primary toner image. A belt 10 as an intermediate transfer member, which is disposed opposite to the photoconductor 8 and is provided so as to allow transfer paper to pass freely between the photoconductor 8 and a belt 10 at a position facing the photoconductor 8 and toward the back side of the belt 10. A primary toner image transfer unit 11 composed of a charger that is immovably arranged, and a portion on the upper surface side of the belt directly opposed to the photoconductor, that is, a downstream side in the belt movement direction from a portion where the primary toner image transfer unit 11 is provided. And a belt cleaning unit 13 provided downstream of the secondary toner image transfer unit 12 in the belt movement direction. Charger 14 as a double-sided copy polarity inversion means provided in opposition to the belt at the downstream than the stage 13, consists of other auxiliary means.

Here, the primary toner image transfer means 11
Also serves as an intermediate transfer unit for transferring a primary toner image to a belt as a secondary toner image.

The other auxiliary means are, for example, a cleaner 15, a static elimination lamp 16, a main charger 17 and the like provided around the photoconductor 8 in the rotation direction of the photoconductor.

The primary toner image transfer means 11 is connected to a high voltage power supply, and can be switched between a positive voltage application state and a non-voltage application state via a switch. This switching is performed according to the recording mode.

Next, the developing means 9 will be further described.
The developing means 9 includes four developing devices housed in four divided areas in the rotating cylinder.

These four developing devices are a developing device for developing yellow toner, a developing device for developing magenta toner, a developing device for developing cyan toner, and a developing device for developing black toner. Each color toner is stored.

In each of these developing units, the rotating cylinder is rotated in accordance with the arrival of the latent image of the color to be visualized until the developing roller of the developing unit containing the toner of the color faces the photosensitive member 8. Then, it stops at the position facing the photoconductor, and the development is performed.

The belt cleaning means 13 is brought into and out of contact with the belt as necessary or unnecessary for cleaning the belt. The fixing means is indicated by reference numeral 18. this is,
It is disposed downstream of the belt 10 and has a function of heating and fixing an unfixed toner image on transfer paper sent from the belt. The paper feeding unit is a paper feeding unit 19 for holding the transfer paper S in a stacked state, and a separation feeding roller 2 for separating and feeding the transfer paper.
0, a pair of registration rollers 23 and the like arranged upstream of the belt. When recording an image, the transfer paper is sent from the pair of registration rollers to the belt.

The transfer paper conveying means is provided along a roller and a guide provided along a path 25 for guiding the paper from the fixing means 18 to the stack section 24, and along a path 26 for recycling to the registration rollers 23 through the fixing means 18. Rollers and guides, and switching claws for selecting these paths.

Two modes are prepared for the transfer mode of the transfer sheet S. One is a one-pass mode in which the paper feed unit 19 passes through the photoreceptor 8 to the fixing unit 18 and follows a path 25. The registration roller pair 23 is reached, and the photoconductor 8, the fixing unit 18,
This is a recycle mode that follows the path 25 and reaches the stack unit 24. Selection of these modes is arbitrarily possible.

The secondary toner image transfer means 12 comprises a dielectric rubber roller or the like, is connected to a high voltage power supply, and can be switched between a positive voltage application state and a non-voltage application state through a switch. Has become. This switching is performed according to the recording mode.

Example 1 (Backside Transfer) (See FIGS. 1 and 2) Members having the same functions as those in FIG. 5 will be described using the same reference numerals.

In the first mode in which the primary toner image is directly transferred to the surface of the transfer paper or the belt surface, the belt 10 is in contact with the photosensitive member 8 as shown in FIG. When the switch SW1 is turned on, a positive voltage is applied to the primary toner image transfer unit 11. Further, the secondary toner image transfer means 12 is connected to the belt
0 and the switch SW
By turning off 2, 2 is in a non-functional state.

In this state, the negatively charged primary toner image T1 carried on the photoreceptor 8 is transferred onto the belt 10 as a secondary toner image T2. Alternatively, the image is transferred to the transfer paper surface on the belt. When the image is transferred to the surface of the transfer paper, the transfer process is completed and the image is discharged after fixing.

When the image is transferred onto the belt, it is rotated together with the belt in preparation for the next transfer process in the second mode. In the second mode in which the secondary toner image is transferred to the back surface of the transfer paper, the belt 10 is separated from the photoconductor 8 as shown in FIG. The primary toner image transfer means 11 is in a non-functional state by turning off the switch SW1.
When the switch SW2 is turned on while being in contact with 0, a functional state ( positive voltage application state ) is established.

Then, the transfer paper S sent onto the belt 10 at a time with the negatively charged secondary toner image T2 carried on the belt 10 is conveyed together with the belt, and
When passing through the next toner image transfer means 12, the secondary toner image is transferred to the back surface of the transfer paper. After the transfer, the sheet is fixed and discharged according to the first mode.

As described above, the belt is controlled to move toward and away from the photosensitive member in accordance with the mode switching between the first mode and the second mode.
2 is also switched on and off.

The means for controlling the contact and separation of the belt with respect to the photoreceptor is constituted as follows. Belt 10 is 2
Opposing roller 4 in opposition to next toner image transfer means 12
0 and other idle rollers 41, 42 and the like. These rollers are pivotally supported by a frame (not shown), and the primary toner image transfer means 11 is attached to the frame to constitute a belt unit as a whole.
The entire belt unit is rotatable around J as a fulcrum.

The rotation is limited to one of the two positions shown in FIG. 1 in which the belt 10 is in contact with the photoreceptor 8 and the state shown in FIG. The rotation power is given by the means, and the posture after the rotation is maintained by an appropriate locking means.

That is, an eccentric cam 50 that rotates integrally with the shaft 49 is provided below the belt 10 corresponding to a position directly below the photosensitive member 8.
The pushing amount of the belt unit changes in accordance with the rotation of the eccentric cam, and the contact / separation control of the belt with respect to the photosensitive member is performed. With the mode conversion, the eccentric cam is rotated by a predetermined amount and stopped. The contact position of the eccentric cam 50 with the belt is a non-image forming area.

In this manner, the belt is displaced away from the photosensitive member except when necessary, so that interference of the transfer sheet with the photosensitive member is avoided, and the reliability of the sheet conveyance is ensured, and the occurrence of an abnormal image occurs. Disappears. In addition, the power consumption of the photosensitive member is stopped at the time of the separation displacement, so that useless power consumption can be avoided, and the primary toner image transfer unit 11 and the secondary toner image transfer unit 12 are appropriately set to the non-functional state. Similarly, wasteful power consumption is avoided.

Example 2 (Back Transfer) (See FIG. 3) In this example, the structure of the members is the same as in Example 1 above. The transfer process in the first mode is exactly the same. However, the difference from the first embodiment is that the switch SW1 is turned on in the second mode as shown in FIG. By doing so, the transfer paper S is brought into close contact with the belt by the electrostatic attraction force of the primary toner image transfer means 11, so that the transfer paper S is surely conveyed toward the secondary toner image charging means 12 to avoid abnormal transfer. it can.

Example 3 (Back Transfer) (See FIG. 4) In this example, the configuration of the members is such that the roller 60 is added to the configuration shown in FIGS. As shown in FIG. 4, the roller 60 is provided so as to be freely contacted and separated by a solenoid with respect to a belt corresponding to the top of the idle roller 41. In addition, other than the solenoid,
For example, a cam or the like can be used.

In this embodiment, in the transfer step in the first mode, the roller 60 is separated from the belt. This is because the secondary toner image on the belt is not damaged. In the second mode, the roller 60 is brought into contact with the belt. The states of the switches SW1 and SW2 are the same as in the first embodiment (see FIG. 4).

In this way, the transfer paper and the belt are brought into strong contact with each other by being pressed by the roller 60, so that the transfer can be reliably performed without causing a shift, and abnormal transfer can be avoided.

[0049]

According to the present invention, a recording apparatus capable of freely recording on both the front and back surfaces of a transfer sheet is provided. It is possible to prevent the intermediate transfer member from becoming unstable due to the electrostatic attraction force, thereby preventing abnormal transfer.

[0050]

[Brief description of the drawings]

FIG. 1 is a front view illustrating a main part of a recording apparatus according to the present invention in a first mode.

FIG. 2 is a front view illustrating a main part of the recording apparatus according to the present invention in a second mode.

FIG. 3 is a front view illustrating a main part of the recording apparatus according to the present invention in a first mode.

FIG. 4 is a front view in a second mode illustrating main parts of the recording apparatus according to the present invention.

FIG. 5 is a front view illustrating the overall configuration of a recording apparatus suitable for implementing the present invention.

[Explanation of symbols]

 Reference Signs List 8 photoreceptor 10 belt as intermediate transfer member 11 primary toner image transfer unit 12 secondary toner image transfer unit S transfer paper

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-56-109380 (JP, A) JP-A-58-48082 (JP, A) JP-A-61-117582 (JP, A) JP-A-1- 209470 (JP, A) JP-A-1-209472 (JP, A) JP-A-3-167580 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/16 G03G 15 / 00 106

Claims (1)

(57) [Claims] A belt-like intermediate transfer member which is configured to be able to freely contact and separate from the photosensitive member and has a substantially horizontal belt surface; and a photosensitive member provided at a position facing the photosensitive member with the intermediate transfer member therebetween. A primary toner image transfer unit having a voltage application function of transferring the upper primary toner image to the intermediate transfer member as a secondary toner image; and a downstream side of the primary toner image transfer unit in a transfer paper transport direction. And a secondary toner image transfer means for transferring a secondary toner image on the intermediate transfer body to transfer paper,
In the case of surface recording, a transfer paper is passed between the intermediate transfer member and the photosensitive member while the intermediate transfer member is in contact with the photosensitive member to transfer a primary toner image on the photosensitive member. The primary toner image on the photoconductor is transferred as a secondary toner image on the intermediate transfer member while the intermediate transfer member is in contact with the photoconductor in the case of transfer on the front surface of paper and the backside recording. After the transfer, the intermediate transfer body is separated from the photoreceptor, a transfer sheet is placed on the intermediate transfer body and conveyed, and the secondary toner image on the intermediate transfer body is transferred at the position of the secondary toner image transfer unit. A recording device capable of transferring the secondary toner image onto the back surface of the paper, after the transfer of the primary toner image to the intermediate transfer member is completed, the transfer paper is placed on the intermediate transfer member during the back surface recording In the process of moving together with the intermediate transfer body toward the transfer means, A recording apparatus characterized in that the toner image transfer means is in a functional state.