JPH04109771U - Transfer device - Google Patents

Abstract

(57) [Summary] [Purpose] Regarding the transfer device that is incorporated into various image forming devices such as copying machines and printers using electrophotographic process and transfers the toner image on the surface of the image carrier to the transfer material, the transfer roll type The purpose is to take advantage of the advantages, prevent the occurrence of toner stains, and even if the toner gets dirty, it can be easily cleaned. [Structure] A conductive elastic member 31 to which a transfer voltage is applied is disposed facing the photoreceptor drum 11, and between the photoreceptor drum 11 and the conductive elastic member 31, there is a thin plate with weak toner adhesion force. A sheet member 32 is interposed. Transfer paper is held between the photoreceptor drum 11 and the thin sheet member 32 to perform the transfer.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention applies to various image forming devices such as copying machines and printers that utilize the electrophotographic process. The toner image formed on the surface of an image carrier such as a photoreceptor drum is The present invention relates to a transfer device for transferring onto a transfer material.

0002

[Conventional technology]

Conventionally, transfer devices used in image forming devices include a corona transfer method and a transfer roller. There are two methods:

0003 In the corona transfer method, for example, a positive charge is generated on the transfer paper by positive charging, and this transfer The transfer paper is brought into close contact with the photoreceptor, which is the image carrier, due to the positive charge on the paper and the negative charge on the photoreceptor. At the same time, the electric field generated at this time transfers the negative toner on the photoreceptor onto the transfer paper. This is a method that allows However, in this method, the transfer voltage is approximately 5kV. Because it requires high voltage, it requires relatively large space and the equipment is complicated. This led to an increase in the cost of the device. Also, especially when When negative voltage is required for photography, ozone generation becomes noticeable and has a negative impact on the human body. was a concern.

0004 On the other hand, in the transfer roll method, as shown in FIG. An electrically conductive sponge-like roll 2 is pressed to have a predetermined nip width, and this roll 2 By applying a transfer voltage of about 1 to 2 kV from power source 3 to A toner image is formed on the transfer paper M that is conveyed between the ram 1 and the roll 2 that rotates as a result of the ram 1. This is a method of transferring. According to such a transfer roll method, the above-mentioned corona transfer method Compared to conventional methods, the entire device is relatively compact because it does not require a high-voltage power supply for transfer. It can be easily configured, is cost-effective, and does not generate ozone, which is harmful to the human body. It has great advantages such as: Therefore, recently, the corona transfer method has been replaced. Therefore, the transfer roll method is becoming widely adopted.

[0005]

[Problems with conventional technology]

A transfer device that uses a transfer roll method has the above advantages compared to a corona transfer method. However, on the other hand, the roll 2 is spongy, i.e. Since it is a porous elastic material, the transfer paper M passes between the photoreceptor drum 1 and the roll 2. or when a narrow transfer paper is being transported. When the photoreceptor drum 1 and the roll 2 come into direct contact, such as when The toner remaining on the drum 1 tends to adhere to the porous surface of the roll 2, causing the toner to dry out. The disadvantage was that it was easy to cause stains.

[0006] If the surface of the roll 2 is stained with toner in this way, the roll 2 may become dirty when the transfer paper M passes through it. The toner on the roll 2 adheres to the back side of the transfer paper M, causing so-called back staining. A problem arose. Furthermore, the degree of toner staining on roll 2 gradually increases. If clogging occurs due to toner, the transfer roll may become clogged due to the toner's insulating properties. The resistance changes and sufficient transfer voltage cannot be obtained, resulting in insufficient toner being deposited onto the transfer paper. There was also the problem that images were not transferred properly, resulting in image defects.

[0007] These problems can be resolved by cleaning Roll 2 regularly. However, there is toner inside the many holes in the sponge-like member that makes up roll 2. These toners cannot be easily removed because they contain fine powder. , so far, even those who are inexperienced in handling the equipment can clean it easily and effectively. No means have been found to do so. In addition, as a cleaning means for roll 2, from the time the transfer paper passes until the next transfer paper is conveyed, and during the last In the post-processing process after the transfer paper has passed, reverse bias is applied to roll 2, and the roll A method has also been considered in which the toner on the drum 2 is reversely transferred to the photoreceptor drum 1. However, due to the strong physical adhesion between the sponge and toner, it is not used as a cleaning function. is insufficient, and electrical costs also increase.

[0008]

[Purpose of invention] In view of the above-mentioned conventional problems, the present invention takes advantage of the advantages of the transfer roll method while also It also prevents toner stains and makes it easy to clean even if they get dirty. The purpose is to provide a transfer device that can.

[0009]

[Key points of the idea]

In order to achieve the above object, the present invention transfers a toner image formed on the surface of an image carrier. In a transfer device that transfers images onto a photographic material, a device that is arranged opposite to the image carrier and applies a voltage for transfer is used. a conductive elastic member interposed between the image carrier and the conductive elastic member; a thin sheet member, and the transfer material is attached to the image carrier and the thin sheet member. It is characterized in that it has a configuration in which the transfer is performed while being sandwiched between the two.

0010

【Example】

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows a schematic configuration of a printer device incorporating the transfer device of the present invention.

[0011] As shown in the figure, this printer device has an image carrier that can rotate in the direction of the arrow. A charger 12, a print head 13, a developer It has a configuration in which a container 14, a transfer device 15, and a cleaner 16 are sequentially arranged. Also, it carries the paper (transfer paper) carried in from the paper feed cassette 17 or the manual feed stand 18. A paper feeder consisting of a standby roll 19, a fixing roll 20, a discharge roll 21, etc. Equipped with a paper transport mechanism. Furthermore, the character code output from the external host device is for converting to dot pattern data and controlling printing operations on paper. An electrical unit 22 including a control circuit board is removably attached to the main body of the device. I'm being kicked.

0012 In the above configuration, the charger 12 charges the photosensitive surface of the rotating photosensitive drum 11 with an initial charge. The print head 13 is a device that applies an electric voltage, and the print head 13 is a device that applies an electric voltage. The developing device 14 converts the electrostatic latent image formed on the photosensitive surface by the above-mentioned exposure. The transfer device 15 is a device for developing with toner, and the transfer device 15 is a device according to a first embodiment of the present invention. The transfer device is a transfer device, the details of which will be described later, that transfers the paper onto the photoreceptor drum 1 to the paper being conveyed. This is a device that transfers a color image. Further, the cleaner 16 remains on the photosensitive surface after transfer. It is a device that cleans and removes toner, and the fixing roll 20 is a device that cleans and removes toner. This device thermally fixes the toner image onto the paper while conveying the toner image.

Next, FIG. 1 shows an enlarged configuration of a transfer device 15 according to a first embodiment of the present invention, which is incorporated into the printer device. As shown in the figure, the transfer device 15 includes a conductive elastic member 31 that is disposed facing the photoreceptor drum 11 in pressure contact with the photoreceptor drum 11 so as to have a predetermined nip width; It is composed of an insulating thin sheet member 32 interposed between the photoreceptor drum 11 and the photoreceptor drum 11 . The conductive elastic member 31 is a conductive sponge-like roll made of polyurethane sponge or the like having a resistance value of about 10 ⁵ to ^{10 10} Ω·cm, for example, like the conventional sponge-like roll 2 shown in FIG. A transfer voltage of about 1 to 2 kV is applied by a power source 33. This conductive elastic member 31 may be configured to be rotatable or may be fixed. The thin sheet member 32 is a flexible sheet-like member with a thickness of about 0.05 to 0.2 mm, made of a material with good releasability from toner and a smooth surface, such as Teflon. One end is fixed to the back side of a paper conveyance guide plate 34 disposed upstream of the conductive elastic member 31 in the transfer paper conveyance direction.

[0014] In the transfer device of this embodiment having the above configuration, the transfer paper is conveyed from the direction of arrow A. Then, after passing over the guide plate 34, the photoreceptor drum 11 and the thin sheet member 32 The conductive elastic member 31 passes over the conductive elastic member 31 while being held between the The toner image on the photoreceptor drum 11 is transferred onto the transfer paper by the transfer voltage applied to the member 31. transcribed into. In this case, there is a gap between the photoreceptor drum 11 and the conductive elastic member 31. Since the thin sheet member 32 whose end is fixed is interposed, the conductive elastic member 31 Although it remains stationary without rotating due to the photosensitive drum 11, the transfer paper is exposed to light. It is conveyed by the conveying force of the body drum 11 and the conveying system before and after it. Also, thin Since the sheet member 32 is a thin insulating member, it and the photoreceptor drum 11 are Due to the principle of transfer, when the transfer paper passes between Qualitatively, it can be regarded as part of the transfer paper, and is therefore equivalent to the conventional transfer roll method. A transfer effect can be obtained.

[0015] Further, according to this embodiment, the sponge-like conductive elastic member 31 is attached to the photoreceptor drum 1. Since there is no direct contact with the conductive elastic member 31, there is no toner contamination on the conductive elastic member 31. It is possible to prevent this from occurring. Moreover, the thin sheet that comes into direct contact with the photoreceptor drum 11 The sheet member 32 has good releasability from toner, so toner does not easily adhere to it, and in the unlikely event that it is Even if the toner is dirty, you can easily remove it with simple cleaning. can be done. In addition, in the conventional transfer roll method, it is not used as a cleaning means. By reversing the polarity of the transfer bias at the right time, a sponge-like Trying to reverse transfer the toner on the roll surface to the photoreceptor drum is a cleaning problem. As mentioned earlier, this method is insufficient as a function of If the thin sheet member 32 is used, the adhesion force with the toner is very small. The toner on the surface of the shaped sheet member 32 can be easily reversely transferred to the photoreceptor drum 11. It is possible to obtain a sufficient cleaning effect.

[0016] Next, FIG. 3 shows the configuration of a second embodiment of the present invention. As shown in the figure, one end of the thin sheet member 32 is connected to the guide plate 34 as shown in FIG. Any member 3 that exists in a stationary state near the bottom of the conductive elastic member 31 instead of It is fixed at 5. The other configurations are the same as those in FIG.

[0017] With such a configuration, the thin sheet member 32 is made of a roll of conductive elastic. It can be arranged in a state where it is wrapped around a part of the circumferential surface of the sexual member 31. of course, The member 35 to which one end of the thin sheet member 32 is attached does not cause any damage due to its attachment. It can be used anywhere as long as it does not cause any negative effects, and it can be wrapped in any way. good. In addition, in order to facilitate cleaning, only the thin sheet member 32 can be easily cleaned. It is also possible to configure it so that it can be removed at any time.

[0018] Next, FIG. 4 shows the configuration of a third embodiment of the present invention. In this embodiment, instead of the roll-shaped conductive elastic member 31 shown in FIGS. 1 and 3, , a conductive elastic member 36 with a square cross section is used, and the material is a roll. This is the same as the conductive elastic member 31 having a shape. In addition, other configurations are the same as those in Figure 1. It is.

[0019] The conductive elastic member 31 shown in FIGS. 1 and 3 is located between this and the photosensitive drum 11. , a thin sheet member 32 with one end fixed is interposed, and the rotation of the photoreceptor drum 11 is Since it is not driven by rolling, there is no need for its shape to be limited to a roll. . Therefore, it is also possible to use a rectangular conductive elastic member 36 as in this embodiment. Therefore, the transfer and cleaning effects are no different from those of the previous embodiment.

[0020] Note that it is capable of being pressed against the photosensitive drum 11 with a predetermined nip width. If so, it is also possible to use conductive elastic members of other shapes. Next, FIG. 5 shows the configuration of a fourth embodiment of the present invention.

[0021] As shown in the figure, a roll-shaped conductive elastic part similar to that shown in FIGS. 1 and 3 is shown. The entire circumferential surface of the material 31 is seamless or seam having a slightly longer circumference. It is surrounded by a thin sheet member 37 configured in the shape of a belt. child The thickness and material of the thin sheet member 37 are the same as those of the thin sheet member 32 described above. Ru. Further, the thin sheet member 37 has a contact portion (nip portion) with the photoreceptor drum 11. Cleaning material made of a material with strong adhesion to toner can be applied to any location except for The contacting member 38 is in constant contact.

[0022] The thin sheet member 37 used in this example is different from the thin sheet member 37 shown in the previous examples. Since one end of the shaped sheet member 32 is not fixed, the photosensitive drum 11 The conductive elastic member 31 rotates along with the rotation of the conductive elastic member 31. At that time, the thin sheet part Since the circumferential length of the material 37 is longer than the circumferential length of the conductive elastic member 31, the thin sheet member 37 is slack. If this slack occurs in the nip area, it may adversely affect the transfer. However, the cleaning member 38 passes through the thin sheet member 37 upstream of the transfer position. Since it is configured to contact the conductive elastic member 31, at least this Looseness always occurs between the location of the cleaning member 38 and the nip portion. The conductive elastic member 31 and the thin sheet member 37 are always in close contact with each other in the nip. Therefore, good transfer is always possible.

[0023] Moreover, as the thin sheet member 37 rotates, the cleaning member 38 is removed. Since dirt adhering to the surface can be wiped off, the thin sheet member 37 can be cleaned regularly. The surface of the thin sheet member 37 can always be kept clean without cleaning. can be done.

[0024] Next, FIG. 6 shows the configuration of a fifth embodiment of the present invention. In this embodiment, instead of using the belt-like thin sheet member 37 shown in FIG. The entire circumferential surface of the conductive elastic member 31 is made of the same material as the conventional thin sheet member. It is covered tightly with a tubular thin sheet member 39. This thin Also for the shaped sheet member 39, the cleaning member 38 is constantly operated as in the case of are in contact.

[0025] In this case, the thin sheet member 39 becomes slack as shown in FIG. The thin sheet member 39 is always in close contact with the circumferential surface of the conductive elastic member 31. state, the toner powder is almost completely prevented from adhering to the conductive elastic member 31. It is completely preventable. Also, similar to the one shown in Fig. 5, the cleaning section Since the material 38 constantly wipes off dirt adhering to the surface of the thin sheet member 39, the thin sheet member 39 Even if the sheet member 39 is not cleaned regularly, the surface of the thin sheet member 39 can be constantly cleaned. It can be kept in a clean condition.

[0026] In addition, in the examples described above, an insulating material was used as the thin sheet member. However, it is also possible to use conductive materials. If a conductive material is used , since the conductive elastic member in contact with it is originally conductive, the transfer In principle, the thin sheet member can also be considered as a part of the conductive elastic member. Therefore, the transfer effect is almost the same as when using an insulating material, and there are no problems. There is no problem. However, as in the examples shown in Figs. 1, 3, and 4, thin sheet members If a part is supported by another member, the supporting member is insulating. However, if it is conductive like a metal plate, at least the support It is necessary to insulate the parts.

[0027] In addition, as a thin sheet member, we use Teflon, which has extremely good releasability from toner. As mentioned above, this is just one example, and it may have a negative effect on the transfer. Unless it's something that doesn't smear and has strong toner adhesion like a sponge, Other materials may also be used. For example, in the embodiments shown in FIGS. 5 and 6, The cleaning member is always in pressure contact with the cleaning member, resulting in very good cleaning. As a thin sheet material, it is more durable than Teflon-based materials. It is also possible to use nylon and rayon materials, which have poor mold releasability. be.

[0028] Furthermore, the conductive elastic member also provides appropriate pressure to the photoreceptor drum, resulting in good transfer. If possible, in addition to spongy materials such as polyurethane sponge, For example, highly flexible and conductive rubber can also be used.

[0029] In addition, the present invention is applicable not only to the printer device shown in Fig. 2, but also to electrophotographic processing devices. If the image is formed by process, the transfer device of another image forming device such as a copying machine can be used. It can also be applied to

[0030]

[Effect of the idea]

According to the transfer device of the present invention, the image carrier (photosensitive drum) and the conductive elastic member are connected to each other. Conductive elastic material that is difficult to clean by interposing a thin sheet member between It is possible to prevent toner stains on the parts, and even if the thin sheet parts become dirty, it is extremely easy to do. Can be cleaned. This way you can eliminate toner stains. This prevents stains on the back of the transfer paper, and the resistance of the conductive elastic member prevents toner clogging. Since the image quality does not change due to interference, stable image quality can always be obtained.

[0031] Moreover, a thin sheet member is interposed between the image carrier and the conductive elastic member. Since it does not affect the transfer operation in any way, it does not require a high-voltage power source for transfer. Conventional transfer rollers do not generate ozone, can be configured compactly, and are inexpensive. You can take full advantage of the advantages of the traditional method.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a printer device incorporating the transfer device of the present invention.

FIG. 3 is a configuration diagram of a second embodiment of the present invention.

FIG. 4 is a configuration diagram of a third embodiment of the present invention.

FIG. 5 is a configuration diagram of a fourth embodiment of the present invention.

FIG. 6 is a configuration diagram of a fifth embodiment of the present invention.

FIG. 7 is a configuration diagram of a transfer device employing a conventional transfer roll method.

[Explanation of symbols]

11 Photosensitive drum 31, 36 Conductive elastic member 32, 37, 39 Thin sheet member 33 Power supply for transcription 38 Cleaning member

Claims (2)

[Scope of utility model registration request] 1. A transfer device for transferring a toner image formed on the surface of an image carrier onto a transfer material, comprising: a conductive elastic member disposed opposite to the image carrier and to which a transfer voltage is applied; a thin sheet member interposed between the body and the conductive elastic member, and the transfer material is transferred while being sandwiched between the image carrier and the thin sheet member. Device. 2. The transfer device according to claim 1, wherein the thin sheet member is insulating.