JPS6149663B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transfer material feeding device in a transfer printer that transfers an image formed on an image carrier by electrophotography onto a transfer material. More specifically, the present invention relates to a transfer material feeding device in a transfer type printer that transfers a developed image or a latent image on a photoreceptor or insulator, which is a drum-shaped or endless belt-shaped image carrier, onto a transfer material. In the following introduction to the prior art and explanation of the present invention, a photoreceptor is used as an image carrier, and the image on the photoreceptor to be transferred to a transfer material is a developed image in which a latent image is visualized using a developer. Let me explain using a statue as an example.

When using an electrophotographic device that records an image by transferring an image developed by a developer on a photoconductor onto a transfer material as a high-speed output device for an information processing system such as a computer, the transfer material should be easy to handle and transport stable. Continuous paper such as fan, fold paper, and roll paper is usually used for reasons such as flexibility. In order to transfer developed images that are intermittently formed depending on the presence or absence of recorded information onto continuous paper, it is necessary to feed the transfer paper intermittently. There are drawbacks such as. The disadvantage is that when continuous paper is conveyed intermittently and intermittent transfer is performed in synchronization with the image on the photoreceptor, that is, when transfer corona charging or transfer roller pressure is turned ON and OFF for transfer, the above-mentioned transfer paper The rise and fall of the conveyance speed may cause image deviation due to deviation from the photoreceptor speed, or transfer failure may occur due to the transfer corona or the responsiveness of the roller. FIG. 1 shows a transferred image on a transfer material P1 showing an example of this, in which such an image trailing end non-transferable area a and leading end transferable area b occur. This is especially true in the case of fan and hold paper, which should be recorded synchronously on a page-by-page basis, where the presence of unrecordable or unclear areas at the leading and trailing edges is inconvenient, and paper transport and transfer There are technical limits to increasing the responsiveness and reducing the unrecordable area.

In order to avoid the above drawbacks, the transfer material is started earlier than the leading edge of the image, and the transfer is started when the conveyance speed of the transfer material and the transfer corona reach a steady state. It is possible to prevent the formation of images, but in this conventional method, as shown in Figure 2, the transfer material is transported during that time, so the developed image is not transferred to the transfer material, and the transfer material is It will be used in vain.
Further, when the transfer material is peeled off from the photoreceptor when the transfer material is stopped in order to prevent stains due to fogging or the like when the transfer material is stopped, the above-mentioned problem becomes even more noticeable. In FIG. 2, P2 is a transfer material, area c is a blank area created to slow down the transfer material, and area d is a blank area created to run up the transfer material prior to the start of transfer.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the conventional transfer method and to prevent the occurrence of blank areas due to misalignment of images and non-transferable areas on a transfer material.

To achieve the above object, a transfer material feeding device in a transfer type printer that intermittently transfers image information on an image carrier to a continuous transfer material that is intermittently conveyed transfers the image information on the image carrier to the transfer material. a conveyance means for starting the transfer material early so that the conveyance speed of the transfer material reaches a constant state at the transfer position before transferring the image to the image carrier, and conveying the transfer material at the same speed as the image carrier during transfer; a contacting/separating means for separating the transfer material from the image carrier in response to the completion of transfer of the image information on the image carrier and bringing the transfer material into contact with the image carrier in response to the start of transfer of the image information on the image carrier; , the transfer material is moved in the returning direction with the transfer material separated from the image carrier so that the transfer end position of the previously transferred transfer material and the next transfer start position are continuously formed on the transfer material. It has a driving means. The above-mentioned image carrier of the present invention refers to a conventionally known photoreceptor in the form of a drum or web, or an insulator capable of retaining charge. Examples of images formed on these image carriers by the above-mentioned electrophotographic method include a latent image on a photoreceptor, a developed image obtained by making the latent image visible with a developer, and It may be a latent image of a drum-shaped insulating member onto which a latent image of the body is transferred, or a developed image of the latent image. The above-mentioned intermittent images formed on the image carrier mean cases in which an image is not formed due to the presence or absence of information between images, as well as cases in which an image cannot be formed due to the structure of the image carrier. There is also. In these cases, since the images are not continuous, this is referred to as intermittent in the present invention.
The present invention will be described in more detail below with reference to Examples.

FIG. 3 is a diagram showing the entire apparatus implementing the present invention. A laser beam 2 emitted from a laser oscillator 1 is modulated according to an input signal to a modulator 3, and then scanned by a rotating polygon mirror 4 to form an image on a drum-shaped photoreceptor 7 rotating in the direction of the arrow. be done. Note that other means (eg, cathode ray tube, plasma, display, etc.) can also be used for optical image exposure.

Various electrophotographic processes that have been proposed in the past can be applied to the present invention, and as an example, the present invention can be carried out using the process described in Japanese Patent Publication No. 42-23910 of the present applicant. Explain.

The photoreceptor 7 of the device shown in FIG. 3 has a basic structure consisting of a conductive support, a photoconductive layer, and an insulating layer on the surface, and is uniformly charged in advance by a primary corona charger 8, and then is exposed to light by the laser beam. Along with the image exposure, an AC corona discharge is performed by an AC corona discharger 9, and the entire surface of the photoreceptor 7 is uniformly exposed by a full-surface exposure lamp 10. As a result, an electrostatic latent image is formed in accordance with the above-mentioned optical image. is formed on the surface of the photoreceptor 7.

This electrostatic latent image is developed with a developer mainly composed of charged colored particles (toner) in a developing device 11, and is visualized. The developed image is transferred to the transfer material by a tractor 16 having a sprocket pin that engages with a sprocket on the transfer material side, and a first intermediate conveyance device 22 having a suction fan 32 and a perforated belt 31. The image is transferred to a certain fan and hold paper 15 (hereinafter also referred to as transfer paper or simply paper) using the electric field generated by the transfer rollers 19 and 21 and the transfer corona discharger 20.

When the information recording on the photoconductor 7 is finished and the last part of the image has been transferred to the transfer paper, the transfer roller 1
9 and 21 are released, the corona discharge for transfer is stopped, the transfer paper 15 is separated from the photoreceptor 7, and the tractor 16 starts to rotate in reverse. As a result, the transfer paper on the conveyor belt 31 is moved by the suction fan 32.
The transfer paper 15 is peeled off from the surface of the photoreceptor by the application of tension that causes it to move forward. Further, at the same time, the backward tension applied to the transfer paper due to the reverse rotation of the tractor 16 is stronger, so that the transfer paper 15
The image is moved back by an amount sufficient to prevent deviation or blurring when restarting, and then stopped. Thereafter, when the image is recorded on the photoreceptor 7 again, the transfer rollers 19 and 21 press the transfer paper 15 against the photoreceptor 7 again, and the transfer corona discharger 20 A voltage is applied to the rear end of the previously transferred image on the paper 15 and the leading edge of the developed image on the photoconductor 7, so that the rear end of the previously transferred image on the paper 15 and the leading edge of the developed image on the photoreceptor 7 are continuous, that is, as a continuous image without any deviation or blurring at the image continuation seam. Photoreceptor 7 is placed on transfer paper 15.
The upper developed image is transferred and recorded.

The transfer paper 15 on which continuous images have been formed as described above is transported forward by the first intermediate transport device 22, the second intermediate transport device 24, and the transport roller 26, and the transfer paper 15 is transported to a predetermined position. loaded into position. Note that a buffering plate 23 is disposed between the first and second intermediate conveyance devices to constantly lift the transfer paper 15. The plate 23 rotates around a rotating shaft at its end due to the tension applied to the transfer paper 15, thereby preventing the paper 15 from being pulled between the conveyance paths. Further, the paper 15 is transferred to a fixing roller 25 disposed between a conveyance roller 26 and the conveyance device 24.
The buffering plate 23 also controls the operation of the fixing roller 25. Specifically, the fixing roller 25 is operated when the transfer paper 15 is operated and the plate 23 is rotated from the set position and the paper 15 becomes slack. Note that when the transfer paper 15 is not in the conveying state, the pressure mechanism of the fixing roller 25 is released, and as a result, the transfer paper 15
will no longer be heated.

On the other hand, after the photoreceptor 7 has completed the transfer process, the developer remaining on the photoreceptor 7 is rubbed off by a cleaning means 12, and the remaining charge on the photoreceptor 7 is removed by a lamp 14 and an AC corona discharger. is removed and prepared for the next image forming step.

Next, the transfer section of the above device will be described in detail.
FIG. 4 is a partially enlarged view of the transfer section. As shown in the figure, the first transfer roller 19 and the second transfer roller 21, whose surfaces are covered with insulating rubber, are arranged close to each other on both sides of the transfer corona discharger 20 so as to sandwich it therebetween. These rollers 19 and 20 are used to prevent image distortion due to the spread of corona discharge, that is, disturbance of the electric field before the transfer electric field contacts the transfer paper 15 and photoreceptor 7 due to corona discharge, and the developed image on the transfer paper 15 that occurs after separation. Prevents scattering and image blurring. Furthermore, by pressing the transfer paper 15 against the photoreceptor 7 using these rollers, the perforations prevent defects due to lifting of the transfer paper, especially when fan-hold paper is used as the transfer paper. It also has the effect of eliminating the problem and ensuring stable and uniform transfer.

On the other hand, during non-transfer, the first transfer roller 19 and the second transfer roller 21 are released from the pressure contact of the transfer paper 15 against the photoreceptor 7 by the first plunger 29 and the second plunger 30, and return to the position shown by the broken line in the figure. . Furthermore, at the same time, the upper guide plate 28, which is incorporated into the same substrate (not shown) as the first transfer roller 19, is pulled by the spring 28b and rotated about the shaft 28a when the first plunger 29 is released. Since this rotation acts in the direction of peeling the transfer paper 15 from the photoreceptor 7, the peeling of the transfer paper 15 is further ensured.

FIGS. 5 and 6 are schematic diagrams illustrating a mechanism for conveying and returning the transfer paper 15. FIG. In FIG. 5, the photoreceptor 7 includes a drive motor 33, a pulley 40 provided on the rotating shaft of the motor 33, a power transmission member 44 such as a timing belt or chain hung on a pulley 41 facing the pulley 40, and the above-mentioned pulley. It is driven by a gear 46 that is coaxial with 41 and a gear 47 that meshes with the gear 46. Further, the drive motor 33 has pulleys 42, 43,
The transfer paper 15 is transported forward by a timing belt 45, a transfer paper transport clutch (for example, a micro powder clutch) 37, and the tractor 16. The transport of the transfer paper 15 is controlled by a clutch 37 that is controlled based on pulse signals generated by a rotary encoder 35.
The transfer paper 15 is fed in synchronization with the photoreceptor 7. On the other hand, when the recorded information is interrupted, the conveying clutch 37 is released and the reversing clutch 38 is made conductive to drive the paper return motor 34. , the gear 5 rotates through a gear 53 attached to the drive shaft, a gear 52 meshing with the gear 53, and a clutch 38.
1 and the gear 50 that meshes with the gear 51, the tractor 16 rotates in the reverse direction, and the transfer paper 15 is returned. The fact that the transfer paper 15 has been returned by a predetermined amount is counted by the rotation of the tractor 16 and the rotary encoder 36 which is activated by this rotation amount, and when the transfer paper 15 is returned by a predetermined amount, the stopping clutch 39 is activated and the tractor 16 is stopped. Therefore, the transfer paper 15 stops. When information is recorded on the photoreceptor 7 again,
The conveyance clutch 37 is actuated by a signal from the rotary encoder 35, and conveyance of the transfer sheet is resumed synchronously. At this time, as described above, at the transfer position, the transfer rollers 19 and 21 move toward the photoreceptor 7 to bring the transfer paper 15 into contact with the photoreceptor 7.

In FIG. 5 above, the transfer paper 15 is
Although the conveyance and return by the tractor 16 in the case of hold paper has been explained, the tractor 16 may be a pair of rollers, and in this case, a sprocket is not necessary for the transfer paper, and a belt-shaped transfer paper such as roll paper is used. You can also do that.

FIG. 6 is a schematic diagram illustrating another embodiment in which the same drive source is used for driving the tractor 16 in reverse as well as in forward rotation. When conveying paper forward, that is, in the forward direction,
A clutch 62 for forward conveyance operates, and a clutch 63 for reverse rotation operates when returning the transfer sheet. In FIG. 6, 59 is a gear driven by a drive source, and a gear 57 is coaxially with the gear 59.
The gear 58 meshes with the gear 58 and constantly rotates in the opposite direction.
These rotations are activated by the clutches 62 and 63, and the tractor 16 is rotated forward or reverse via the gear unit 64. In the figure, reference numeral 60 indicates a stopping clutch, and reference numeral 61 indicates a rotary encoder serving as an operating reference for these tractors 16.

Above, in FIGS. 5 and 6, we have described an embodiment in which the transfer paper is returned by reverse rotation of the conveyance means using a tractor as an example. , an example of returning the transfer paper will be described. FIG. 7, which shows one example, shows an embodiment in which the transfer paper is pulled back by moving the roller position.

In FIG. 7, during normal transfer, the paper is transported by a certain amount by the transport tractor 16 and the intermediate transport device 22. When the recording information is lost and the transfer is turned off and the paper 15 is separated from the photoconductor 7 by the mechanism shown in FIG.
4, lowers the conveyance roller 17, and pulls back the transfer paper 15. Then, when the information comes again and transfer starts again, the cam 55 rotates further, swings the arm 54 again around the shaft 64, and the roller 1
7 is raised, but the contact position of the paper is controlled by the shape and rotation timing of the cam 55, and the operation is essentially to pull back the transfer paper and perform the transfer.
Returning the transfer sheet can also be achieved by moving, swinging, or twisting the conveyance guide plate 56 in a similar manner. In each of the above figures, parts that have the same function are given common numbers throughout the figures. Further, in the above embodiment, an example was shown in which a developed image is transferred to a transfer material, but it is also possible to transfer a latent image on an image carrier to a transfer material, and then make the latent image visible later.

By transferring the transfer material to the image carrier as described above, including the operation of returning the transfer material, it is possible to obtain an intermittent image on the image carrier as a continuous image on the transfer material. The present invention can prevent image misalignment on the transfer material and the occurrence of blank areas due to non-transferable areas, so it is possible to use the transfer material more effectively than with transfer using a conventional transfer material conveyance mechanism. It became.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams showing an example of transfer by a conventional transfer method, FIG. 3 is a schematic cross-sectional view showing the configuration of an image forming apparatus to which the present invention is applied, and FIG. 4 is an illustration of the apparatus shown in FIG. FIG. 5 is a top view of the drive unit showing a transfer material conveyance mechanism; FIG. 6 is a top view of the drive unit showing another embodiment of the transfer unit; FIG. 7 is a top view of the drive unit according to the present invention. In the configuration explanatory diagram showing a part of the image forming apparatus showing another embodiment, in the diagram, 7...photoreceptor, 11...developing device, 15...transfer paper, 16...tractor, 17...transport roller , 19/21...Transfer roller, 22...First intermediate conveyance device, 23...Buffling plate,
24... Second intermediate conveyance device, 25... Fixing device,
26... Conveyance roller, 33, 34... Drive motor, 35, 56... Rotary encoder, 37
~39...Clutch, 40~43...Pulley,
54...roller arm, 55...cam, 56...
guide board.

Claims (1)

[Claims] 1. In a transfer material feeding device in a transfer printer that intermittently transfers image information on an image carrier to a continuous transfer material that is intermittently conveyed, the image information on the image carrier is transferred to the transfer material. A conveyance means that starts the transfer material early so that the conveyance speed of the transfer material reaches a constant state at the transfer position prior to transfer, and conveys the transfer material at the same speed as the image carrier during transfer; a contact/separation unit that separates the transfer material from the image carrier in response to the completion of transfer of the image information on the image carrier and brings the transfer material into contact with the image carrier in response to the start of transfer of the image information on the image carrier; A drive that moves the transfer material in the direction of returning the transfer material while it is separated from the image carrier so that the transfer end position of the previously transferred transfer material and the next transfer start position are continuously formed on the transfer material. A transfer material feeding device in a transfer type printer, comprising: means. 2. A transfer material feeding device in a transfer type printer according to claim 1, wherein the contacting and separating means includes rollers provided upstream and downstream of the transfer corona discharger.