JPH04190374A - Color image forming system and color image forming device - Google Patents

Abstract

PURPOSE:To facilitate the formation of a color image without incurring enlargement of the size of a device and retardation of the image forming speed by preparing a number of toner image forming means, corresponding to the number of colors so as to form a single color toner image by each of the forming means, and by transferring a plurality of color toner images successively to a recording medium during image transfer operation so as to form a color image. CONSTITUTION:At cartridge 5Y..., different color toner images are successively formed with time differences which obtained by multiplying a differential distance to an image transfer position facing the corresponding photosensitive medium drum 51 with a recording sheet conveying speed, and are then led successively onto the peripheral surface of an image transfer roller 4 with a timing set by a register roller 7 before they are transferred onto a recording sheet. Further, thus transferred toner images are fixed by a heating element 42 disposed in the roller 4, simultaneously with the image transfer. Accordingly, it is possible to prevent mixture between the previous toner image and the following toner image. Further, the recording sheet on which four color toner images have been transferred and fixed is led to a sheet discharge tray 2 by means of a sheet discharge roller 8. Thereby it is possible to shorten the recording sheet conveying path and to facilitate the miniaturization of the device.

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] [Industrial Application Field] The present invention relates to a color image forming method and apparatus for forming a multicolor image using a plurality of types of toners, and particularly relates to a color image forming method and an apparatus thereof that perform image transfer and fixing almost simultaneously. The present invention relates to a color image forming method and an apparatus thereof.

[0002] [Prior Art] Conventionally, electrophotography and other color photosensitive drums or other image carriers sequentially carry toner images of four primary colors of cyan, magenta, yellow, and black to form color images. Image forming apparatuses are well known.

On the other hand, in recent years, a photoreceptor drum formed by laminating a transparent conductive layer and a photoconductor layer on a transparent support has been used, and the exposure means is placed on the inner circumferential side of the drum, and the charging and developing steps are performed on the drum. An image forming apparatus is also known in which the image forming apparatus is disposed on the outer circumferential side and development is performed at the same time as or immediately after exposure. (Unexamined Japanese Patent Publication No. 58
153957 and others, hereinafter referred to as a back exposure device) [0003] Colorization is also being considered in this type of back exposure device; for example, in JP-A-1-102583,
A number of exposure means corresponding to each color are provided on the inner peripheral side of the drum,
Further, a technique has been proposed in which a number of charging means and developing means corresponding to each color are arranged on the outer circumferential side of the drum, and charging, exposing, and developing are repeatedly performed for each color, thereby enabling multicolor development.

[0004] [Problems to be Solved by the Invention] However, in this technique, it is necessary to arrange at least three or more exposure systems inside the photoreceptor drum, and to alternately arrange charging means and exposure means on the outer circumferential side of the drum. As a result, the outer diameter of the drum must be increased accordingly, and the apparatus itself must be made considerably larger.

[0005] In order to eliminate this drawback, only three or four developing devices are arranged in the circumferential direction, while the exposing device and the charging device are arranged one by one on the upstream side in the drum rotational direction of the arrangement position of the developing device group. arrangement,
A technique has also been proposed (Japanese Unexamined Patent Publication No. 198466/1999) that uses the pair of exposure device and charger to repeat charging and exposure every rotation of the drum, thereby enabling multicolor development while developing corresponding colors. However, this technique has the disadvantage that the drum must be rotated by the corresponding number of colors (the number of developers), which inevitably slows down the image forming speed.

[0006] In view of the drawbacks of the prior art, the present invention provides a method for easily forming a color image without increasing the diameter of the drum, without increasing the size of the apparatus as a result, and without causing a delay in image speed. The object of the present invention is to provide an image forming apparatus that can perform the following steps.

[Means for Solving the Problems] In order to achieve the above technical problems, the present invention, like the above-mentioned prior art, arranges a plurality of developing units on the photosensitive drum, and sequentially develops them on the drum. Rather than forming a multicolor image by superimposing toner images of each color while developing them, a number of toner image forming means corresponding to each color is prepared, and each corresponding forming means only forms a toner image of one color. form,
The first feature is that a color image is formed while sequentially transferring the toner images of each color to the recording material side at the time of transfer.

[0008] However, after transferring the first toner image, if an attempt is made to transfer a second toner image while the toner image is unfixed, the image of the first toner image will be disturbed during the transfer of the second toner image. This not only makes clear color superimposition impossible, but also causes a portion of the first unfixed toner image to adhere to the second toner image forming means, further reducing image clarity.

Therefore, the second feature is that the toner image of - is fixed at the same time as the toner image of - is transferred or before the next toner image is transferred.

[0009] The toner image forming means is not limited to a unit body having a back electrode structure in which an exposure device is included in a photoreceptor drum as shown in the above-mentioned prior art; It includes a conventional electrophotographic unit arranged around a body drum, and also one using a belt-shaped photoreceptor layer.

[0010] The invention according to claim 2 embodies such an image transfer method, and includes the following features: a plurality of toner image forming means having the above configuration corresponding to each color are provided; The toner image forming means is provided with a transfer means to which a toner image is transferred. A color image forming apparatus is provided with one or more fixing means for fixing the transferred toner image, and the fixing means may be of a roller type or other type in order to increase the recording speed. In this case, it is preferable that the fixing means is arranged to face the image forming means within the arrangement area of the image forming means with the transfer means in between.

[0011] [Example 1] Hereinafter, an example of the present invention will be described in detail based on the drawings. However, unless otherwise specified, the dimensions, materials, shapes, and relative positions of the components described in this example are not intended to limit the scope of this invention, but are merely illustrative examples. Not too much.

FIG. 1 shows a schematic configuration of an image forming apparatus according to an embodiment of the present invention, in which a paper ejection tray 2 and a paper feed cassette 3 are vertically stacked on the lower end side in a substantially rectangular storage, and the upper center position A large-diameter transfer roller 4 is rotatably disposed, and cartridges 5Y for forming toner images of yellow, magenta, cyan, and black are arranged along the rotational direction of the transfer roller 4, Further, a recording paper conveyance path IO is formed on the path leading to the paper feed cassette 3, the peripheral surface of the transfer roller 4, and the paper discharge tray 2, and along the conveyance path, the paper feed roller 6, the registration roller 7, and the paper discharge roller 8 are formed. to be placed.

10012] As shown in FIG. 2, the transfer roller 4 has a surface layer made of silicone rubber or other heat-resistant rubber material 41, and is equipped with a ring-shaped heating element 42 on its inner circumferential side. The transfer roller 4 is configured to be removable upward along the guide groove 9, and the recording paper conveyance path IO is configured to be openable in case of a jam or other case.

[0013] As shown in FIG. 2, the cartridge 5Y... has a light-transmitting guide 1! on a drum-shaped light-transmitting support 51a. An exposure system consisting of a bibundle lens 53 on five rows of LEDs that generates light output corresponding to image information is housed in the photoreceptor drum 51 formed by laminating the layer 51b and the photoconductor JJ51c. A photosensitive drum 51 facing the image forming position of the exposure system
A developing sleeve 54 is disposed on the outer peripheral side of the container 55, and by rotating the sleeve 54 in the direction of the arrow, the toner of each color stored in the container 55 is brought to a developing position corresponding to the image forming position of the exposure system 52-53. guided by.

After the latent image formed by the exposure system 52-53 is developed, the toner image is guided to a position facing the transfer roller 4 while being carried on the photosensitive drum 51.

[0014] Each of the cartridges 5Y containing yellow, magenta, cyan, and black toners is as follows:
The transfer roller 4 is removably supported and fixed parallel to the transfer roller 4 axis by guide frames 11 arranged in a substantially U-shape at predetermined distances in the circumferential direction of the transfer roller 4 .

[0015J Next, the operation of this embodiment will be explained.

First, on the side of the cartridge 5Y, toner images corresponding to each color are sequentially formed with a time difference corresponding to [distance difference to the transfer position facing the corresponding photoreceptor drum 51 x recording paper conveyance speed], and then The registration rollers 7 take the timing and sequentially transfer the images onto the recording paper guided onto the circumferential surface of the transfer roller 4.

The transferred toner image is fixed at the same time as the transfer by a heating element 42 built into the roller 4.
No mixing with the previous toner image occurs during transfer of the next toner image.

Then, the recording paper onto which the four-color toner images have been transferred/fixed is led to the paper discharge tray 2 side via the paper discharge roller 8.

[0016] FIG. 3 shows another embodiment using a transfer belt, in which a fixing roller 60^ equipped with a heater 61 is arranged at a position facing the photoreceptor drum 51 via the transfer belt 40, The structure is such that image transfer and fixing are performed simultaneously. still
The fixing roller 60B also functions as a revolving belt for the transfer belt, and a plurality of cartridges 5 are arranged on the circumferential surface of the roller.
It is configured such that Y... can be arranged.

[0017] With this configuration, there is no need to provide a fixing roller for each cartridge, leading to a reduction in the number of parts.

[0018] (Effects of the Invention) As described above, according to the present invention, instead of forming a multicolor image by sequentially carrying toner of each color on a photoreceptor drum as in the prior art, Since it is sufficient to carry a toner image of one color, it is possible to downsize the image forming means including the photoreceptor drum, and since the transfer means and fixing means can be integrated, the recording paper conveyance path can be shortened and it can be easily made. It is possible to achieve miniaturization of the device.

Also, like the prior art described above (supported on a photoreceptor drum)
Since a multicolor image is formed by sequentially overlapping unfixed toner images on a fixed toner image without overlapping unfixed toner images, the image clarity of the - layer can be improved.

It has various effects such as

[Brief explanation of the drawing]

[FIG. 11] FIG. 1 is a schematic diagram showing the overall configuration of a color image forming apparatus according to an embodiment of the present invention. (FIG. 2) FIG. 2 is an enlarged view of main parts showing the toner image forming means used in the embodiment. (FIG. 31 FIG. 3 is a configuration diagram of main parts of a color image forming apparatus according to another embodiment. [Explanation of symbols] 4 Transfer means 40 Transfer means 60 Fixing roller 5A... Toner image forming means

Claims (3)

[Claims] 1. In a color image forming system that forms a multicolor image using a plurality of types of toner, a plurality of toner image forming means corresponding to each color are prepared, and the toner image formed by the respective image forming means is transferred to a recording material. While sequentially transferring to the side,
A color image forming method characterized in that the toner image is fixed at the same time as the toner image is transferred or before the next toner image is transferred. 2. A plurality of toner image forming means corresponding to each color, and a transfer means for transferring the toner images as a recording material moves, the transfer means moving the toner image forming means over the transfer means. A color image forming apparatus characterized in that one or more fixing means are sequentially arranged along a direction and are arranged within an arrangement area of the image forming means for fixing the toner image transferred by the transfer means. 3. The color image forming apparatus according to claim 2, wherein the one or more fixing means are disposed facing each other within an arrangement area of the image forming means with the transfer means in between.