JPS6197671A - Picture image forming method - Google Patents

Abstract

PURPOSE:To prevent contamination of a transferring charger, transferring material, etc., and to obtain high-quality picture images, by providing a no-picture image area zone at the side edge section of the transferring material held o a photosensitive body on which a transferring material carrying sheet provided with numerous narrow holes is provided. CONSTITUTION:A light source row 31 composed of numerous light sources arranged in the direction of the generating line of a photosensitive body 1 is provided on the backside of a secondary charger 16. Electric charges on the photosensitive body 1 are removed by selectively controlling the light sources of the light source row 31 corresponding to the outside area of the peripheral area of the electrostatic latent image forming area formed on the photosensitive body 1 in accordance with the size of transferring materials. When a toner image on the photosensitive body 1 provided with numerous narrow holes is extended beyond the endge section of a transferring material, adhesion of toner to a transferring charger back of the transfer is prevented, since no-picture image area zones are provided beside the transferring material. Therefore, the function is stably maintained and high-quality picture images can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an image forming method in which a toner image developed on an image carrier is transferred to a transfer material on a transfer material support.

[Background of the invention]

Conventionally, developed images of different color components of a color image to be formed are sequentially formed on an image carrier such as an electrophotographic photoreceptor, and a transfer material support such as a transfer drum is provided with a transfer material carrying sheet having a large number of pores. Various image forming apparatuses have been proposed, such as a color electrophotographic copying apparatus that sequentially corona-transfers the developed image onto a held transfer material to obtain a color image.

FIG. 4 shows an example of such a color electrophotographic copying apparatus. In the figure, reference numeral 1 denotes a photosensitive drum 9 having a three-layered photosensitive member consisting of an insulating layer, a CdS photoconductive layer, and a conductive layer. Start rotating in direction 3. When the photosensitive drum 1 rotates and reaches the fixed position, the document O placed on the lath 4 is placed on the document table.
It is irradiated by Haguntsung 5. The reflected light is the first
The scanning mirror 7 6 is reflected by the second scanning mirror 7, passes through the lens 8 and the third mirror 9, and is color-separated by the blue filter 101 of the color separation filter group 10.
The near-infrared light component in the color-separated light image is removed by the dichroic mirror (having visible light reflection and near-infrared light transmission characteristics) 11, and only the visible light component is imaged on the photosensitive drum 1 by the exposure section 12. Ru.

The photosensitive drum 1 is uniformly charge-eliminated by an AC charger 13 and a pre-exposure run f14, then charged to di-glass polarity by a primary charger 15, and then charged to a secondary charger 16 at the exposure section. 12
At the same time, a blue color separation image exposure (slit exposure) is applied, and at the same time negative polarity charge removal is performed. Secondary charger 16
A large number of grid wires are provided in the casing opening to control the static elimination potential. Furthermore, a blue color separation latent image is formed on the citrus 1 by performing full-face exposure using the full-face exposure plate 17.

The electrostatic latent image on the photosensitive drum 1 is then transferred to a developing device group 18.
It is visualized as a toner image. The developing device group 18 is
18a, -r center 18b1 cyan 18c1 and black 18
It consists of four developing devices (d), and the specified developing device works according to the color separation filter used for exposure to obtain a toner image of the required color. The color separation latent image is visualized by a yellow developer 18m.

On the other hand, the transfer paper 20 in the force set 19 is fed into the paper feeder 21, and approximate timing is determined by the first registration roller 222m, and then accurate timing is determined by the second registration roller 22b. The tip is gripped by the gripper 231 of the transfer drum 23. Note that the screen 232, which will be described later and which is stretched over the cylinder notch of the transfer drum 23, has electric charge on the front and back sides of the screen removed in advance by separation AC chargers (referred to as separation chargers) 234 and 235. , both sides of the screen are cleaned by cleaners 237 and 238, and charge-up on the screen surface is removed by a charge-up prevention AC charger 40 as required.

The transfer paper gripped by the glyph A231 of the transfer drum 23 is conveyed while being wrapped around the screen 232 as the transfer drum 230 rotates, and while the transfer paper passes between the transfer charger 233 and the photosensitive drum 1, the transfer paper is transferred. The yellow toner image on the photosensitive drum is transferred onto the paper, and the transfer paper is held on the screen surface by electrostatic attraction. At this time, the electrostatic attraction force between the screen 232 and the transfer paper is further strengthened by the action of the grounded electrode 2390.

The transfer drum 23 grips the leading edge of the transfer paper 20 with the glyphs 231 and rotates a required number of times while being electrostatically attracted to the screen, thereby transferring toner images of the required number of colors.

In other words, in the case of a full-color copy, following the transfer of the yellow toner image described above, a magenta toner image is transferred by green color separation exposure, and then a cyan toner image is transferred by red color separation exposure, aligned on the transfer paper and sequentially. It will be done.

When the leading edge of the transfer material approaches the separation position after a predetermined number of transfers, the glyph 231 is released and the separation chargers 234 and 2
35 works and both the transfer material and the screen are neutralized,
The transfer material is separated by the separation claw 236 approaching the screen.

After the transfer material is separated, it is guided by a conveyor belt 27 to a heat roller fixing device 28, where it is fixed by pressure and heat, and then discharged onto a tray 30.

After the transfer, the surface of the photosensitive drum 1 is cleaned by a cleaning device 31 before proceeding to the next cycle.

By the way, as shown in FIG. 5, this transfer drum 23 has a screen 232 which is an insulating transfer material carrying sheet having a large number of pores, and a notch which is a support member that supports this screen at its edge. The provided cylinder 24
0, a gripper 231 that grips the leading edge of the transfer paper, and a transfer charger 233.

The above screens include polyester, nylon, silk,
TI! A material knitted with fibers such as lipropylene or a sheet made of polyester, polypropylene, etc. with holes pressed is used. In both cases, the aperture ratio of the screen is 2
A size of about 0 to 70 inches is used.

In the transfer method using the screen described above, compared to the method using a transfer material carrying sheet made of an insulating film, the transfer corona charge applied to the back surface of the screen (transfer charger side) increases as the number of repeated transfers increases. There are fewer problems such as a decrease in transfer efficiency and a decrease in the electrostatic attraction force of the transfer material due to the so-called charge-ag phenomenon, in which charges of opposite polarity to the transferred corona charges are accumulated on the surface of the yoshiscreen.

This is because the transfer corona passes through the openings in the mesh screen and is applied directly to the back side of the transfer material, and part of the charge-up on the screen surface caused by the transfer corona charge on the back side of the screen is caused by the openings in the screen. The above-mentioned problem is alleviated because the static electricity is removed by the transfer corona passing through the transfer corona.

From this, the transfer method using a screen can provide excellent transfer performance as a multi-transfer device that superimposes and transfers images of different colors onto a transfer material.

However, some difficulties have been pointed out in such a transfer device.

One of these is that if the toner image on the photosensitive drum exists in an area that exceeds the size of the transfer material, the toner is likely to adhere to the discharge wire or shield member of the transfer charger, which may cause a malfunction of the device. This means that transfer defects may occur.

Another problem is that toner adheres to the edge of the back surface of the transfer material.

That is, as shown in FIG. 6, when the toner image T on the photosensitive drum 1 extends beyond the edge of the transfer material 20, the transfer material 2 is transferred by the discharge wire W of the transfer charger during transfer.
0 and the back surface of the screen 232, the toner image T on the photosensitive drum is transferred onto the transfer material, and at the same time, the toner image outside the transfer material area passes through the opening of the screen and is charged with the positive charge of corona ions generated from the discharge wire W. It will be attracted to the electric charge. Therefore, most of the attracted toner is charged with a positive charge while approaching the discharge wire, reversed to positive polarity, repelled near the discharge wire, and attached to the shield member of the transfer charger. Further, a portion of the sucked toner directly adheres to the discharge wire.

When toner adhesion to the shield member or the discharge wire increases, localized dielectric breakdown occurs, causing spark discharge that causes device malfunction, transfer failure, and the like.

Furthermore, some of the attracted toner may directly adhere to the edge of the back surface of the transfer material, the side edges of the transfer material, and the back surface of the screen in the vicinity thereof due to electrostatic force, or may be polarized due to corona charging. The toner that has become stained is pushed away by the corona wind and sticks to it. For this reason, stains occur around the edge 10w and side edges of the back surface of the transfer material.

[Purpose of the invention]

The object of the present invention is to provide a transfer charger, a transfer charger, and a device for forming a non-image area band at the edge of a transfer material held on a transfer material support provided with a transfer material carrying sheet having a large number of pores. The present invention provides an image forming method that prevents staining of a transfer material, etc., and obtains a high-quality image.

[Summary of the invention]

The gist for achieving the object of the present invention is as follows: 1. A transfer material held on a transfer material support provided with a transfer material carrying sheet having a large number of pores is provided with a transfer material that is visualized on an image carrier. The image forming method includes corona transfer of a toner image obtained by corona transfer, characterized in that non-image area bands are formed at positions corresponding to the four edges of the transfer material. ＠＼Momo＼＼＜ζAtsr(＼＼～N＼＼～N＼＼＼～N＼＼＼＼＼～N＼＼＼＼＼＼＼〜N＼＼＼＼＼＼〜N＼＼＼＼＼＼＼～N､＠＼＼＼〜N Weir formation 1
1\\ [Embodiment of the Invention] The present invention will be explained in detail below based on practical examples shown in Figs. 1 to 3, but the structure in this embodiment and the structure shown in the conventional example will be explained in detail. For the same parts, the reference numerals cited in the conventional example are attached to the structure in this embodiment, and a description of the structure will be omitted.

In the figure, reference numeral 31 denotes a light source array in which a large number of light sources (not shown) that can be selectively turned on are arranged in a line in the direction of the generatrix of the photosensitive drum 1, and is disposed on the back side of the secondary charger 16. The light source is 6 to 7 tungsten lamp bulbs,
In the case of an LED array, it is composed of 40 to 50 LED arrays, and when all the light sources are turned on, it is possible to expose substantially the entire width of the photosensitive drum 1.

Then, an electrostatic latent image forming area (
The light sources of the light source array 31 corresponding to the outside of the peripheral area (indicated by diagonal lines in FIG. 1) are selectively controlled to turn on in accordance with the size of the transfer material, and the charges on the photosensitive drum are erased. Therefore, the visualized toner image is formed inward from the peripheral area of the electrostatic latent image forming area, and in the next transfer process, a non-image is formed around the transfer paper as shown in FIG. It is transferred to have area bands A, B, C, and D. This non-image area band A is a portion gripped by the glyph Δ of the transfer drum.

That is, when providing a non-image area band A at the top edge of the transfer paper or a non-image area band C at the bottom edge, all light sources in the light source array 31 are turned on, and non-image area band B or non-image area band B is provided at the side edge of the transfer paper. When a region band is provided, the light sources of the light source array 31 corresponding to the outside from the peripheral region of the electrostatic latent image forming region in the axial direction of the photosensitive drum are turned on.

The selective lighting control of the light source array 31 according to the size of the transfer material may be performed based on a signal specified by the cassette of the transfer material, and the light source array 31 may be selectively turned on according to the size of the transfer material along the conveyance path of the transfer material. A detection device may be provided and the detection may be performed based on a signal from the detection device.

It is sufficient for the width of the non-image area band of the transfer material to be about 1 mm.
Considering the feeding error in the direction of movement of the transfer material or in the direction perpendicular thereto, a width of 2 to 3 m is preferable. Further, in order to obtain sharp edges, it is preferable to use a light source with a narrow irradiation diameter, such as an LED array, close to the photosensitive drum.

[Effects of embodiments of the invention]

As described above, according to this embodiment, when an electrostatic latent image is formed, blank exposure is performed by selectively controlling the lighting of the light source array for the peripheral area of the electrostatic latent image forming area, and the image is developed. By setting the image area of the converted toner image within a range that can have a slight non-image area band at the side edge of the transfer material to which this toner image is transferred, the toner on the photosensitive drum is It is possible to prevent adhesion to the transfer charger, the back side of the transfer material, etc. through the screen of the transfer drum.
□As a result, it is possible to stably maintain the functions of the transfer charger, etc., and it is possible to obtain high-quality images.

Note that the non-image area band on the transfer material is not provided for west side transfers, but is provided as necessary.

You may.

Furthermore, in this embodiment, by selectively controlling the lighting of the light source array, the electrostatic latent image formed on the photosensitive drum is exposed to blank light to form a non-image area band on the side of the transfer material. However, the discharge width of the transfer charger was controlled], and the corona discharge of the transfer charger was controlled to be turned on and off at the leading edge and trailing edge of the image, and was applied to the sides of the transfer material. A non-image area band may also be provided.

In the embodiments described above, the image forming method according to the present invention is applied to an electrophotographic copying apparatus, but it may also be applied to a color laser beam printer. The charge erasure control in the non-image area of the radar beam is the same as in the embodiment described above. In this case, a very sharp white background border can be obtained by radar scanning.

〔Effect of the invention〕

As described above, according to the image forming method of the present invention, it is possible to prevent the toner on the image carrier from adhering to the transfer charger, the back surface of the transfer material, etc. during transfer, so that the transfer charger etc. can be stabilized. The effect is that you can obtain high-quality images.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an apparatus used to carry out the image forming method according to the present invention, FIG. 2 is a side view thereof, and FIG. 3 is an image on a transfer material obtained by the method of the present invention. - Diagram showing the castle, Figure 4 is a sectional view of a conventional color electrophotographic copying machine, Figure 5
The figure is a schematic diagram of the transfer drum, and FIG. 6 is a diagram illustrating the transfer state. 1... Photosensitive drum 2... Shaft 4... Original table glass 5... Halogen lamp 6.
...First scanning mirror 7...Second scanning mirror 8...
Lens 9... Third Mi-10... Color separation filter group 11... Fourth mirror 12... Exposure section 13...
AC charger 14...Pre-exposure lamp 15...-Secondary charger 16...Secondary charger 17...Full-surface exposure lamp 18...Developer group 18a, 18b,
18c, 18d - Developing device 19...Cassette 20...Transfer paper 21...Paper feed roller
22 &...Second registration roller 22b...Second registration roller 23...Transfer drum 27...Transportation tray A/) 28
...Fuser 30...Tray 31...Light source row 231...Glitz 4232...Screen 233...Transfer charger 234.235...AC charger 236...Separation claw 237, 238...Cleaner Figure 1 Figure 2

Claims (1)

[Claims] 1. An image in which a toner image visualized on an image carrier is corona-transferred to a transfer material held on a transfer material support provided with a transfer material carrying sheet having a large number of pores. An image forming method comprising: forming non-image area bands at positions corresponding to four edges of the transfer material. 2. The image forming method according to claim 1, wherein non-image area bands are formed on the four edges of the transfer material depending on the size of the transfer material.