JPH041670A - Color image forming device - Google Patents

Abstract

PURPOSE:To reduce the size of the device by enabling a transfer means to be separated from a photosensitive body and varying the speed of transfer conveyance. CONSTITUTION:A transfer conveyance part 60 has two states, i.e. a state wherein part of a belt 63 suspended by rollers 61 and 62 and movable rollers 67 and 68 is pressed lightly against the photosensitive body 11 and a state wherein the belt separates from the photosensitive body 11, and the conveyance part moves as shown by an arrow B. When the belt 63 is pressed against the photosensitive body 11, the belt moves at the same speed with the outer peripheral speed of the photosensitive body 11, but when the belt separates, the belt moves irrelevantly to the speed of the photosensitive body 11, e.g. at the moving speed of recording paper 56 that a fixation part 70 requires. Consequently, when image transfer to recording paper ends, the transfer conveyance part is separated from the photosensitive body immediately and the recording paper is sent in a fixing means 70 at the speed irrelevant to the speed of the photosnesitive body; and fixation conditions can properly be changed according to the kind of form and the purpose, and the device is reducible in size.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to color copying using electrophotography. Conventional technology generally relates to color image forming apparatuses such as color printers that produce color images with clarity and gloss using electrophotography. In order to fix the toner on the recording material, it is necessary to sufficiently mix the three primary color toners during fixing to develop the desired color.It may be necessary to apply an appropriate amount of heat to the toner.However, the recording material that supports the toner If there is a change in the material or thickness of the toner, under certain fixing conditions, the state of heat conduction to the recording material will change, the amount of heat supplied to the toner will change, and the color tone of the color image will change. , Table 1 when using OHP film as a recording material
The thermal conductivity of this recording material is lower than that of normal paper, and under normal fixing conditions, the amount of heat supplied to the toner is small. (For these reasons, it is necessary for OHP films to have more sufficient fixation than usual.)

On the other hand, when it comes to color images, the glossier the image to some extent, the better the image quality and beautiful strength.For black and white characters, the less glossy the better, the easier it is to read.

In this way, changing the type of recording material and fixing conditions as necessary is an important issue, especially in the case of color image forming apparatuses. FIG. 2 shows a configuration diagram of this conventional image forming apparatus, which is disclosed in Japanese Patent Publication No. 60-51866. The configuration and operation will be briefly explained below. The original on the original platen 101 is placed on mirrors 102, 103 and lens 1.
04, the colors are first separated by the first color filter 105 and projected onto the photosensitive drum 106, but the photosensitive drum 106 is rotating in the direction of the arrow, charged by the primary charger 107, and then irradiated with a light image. The static electricity is removed by the static eliminator 108, and the entire surface is irradiated with light by the exposure lamp 109.
After the electrostatic latent image is created, the first color of the electrostatic latent image is developed in the developing section 110 and reaches the transfer section 111 as a toner image. By this time, paper 1
12 is electrostatically attracted and wound around a transfer drum 113 rotating in synchronization with the photosensitive drum 106 by a charger 114.
Even though the first color toner image on the top is transferred to the paper 112, the photosensitive drum 1 is transferred in the same manner as the transfer drum 113 rotates.
Paper 1 with the same second and third color toner images created on 06
After all the colors have been transferred, the paper 112 is peeled off from the transfer drum 113 by a peeling section 114, passes through the conveyance section 1]5, and then is transferred to the fixing device 116.
is fixed and ejected from the device. At this time, the fixing device 11
The operating speed of 6 is variably controlled in two stages depending on the type of paper 112, so that an appropriate fixing condition can be selected depending on the type of paper 112. The above is a description of the conventional image forming apparatus, and the problem to be solved by the present invention is, however, with the above configuration (the process speed, which is the speed of the photosensitive drum and transfer drum, and the speed of the fixing device operate at different speeds). In this case, the leading edge of the paper 112 is connected to the fuser 116.
At the time when the paper 112 enters the transfer drum 11, the trailing edge of the paper 112 is
(-Because if even part of the paper 112 remains on the transfer unit 111 during fixing, the difference in paper speed will cause a shift in fixing, etc., and the image will be distorted.) In addition, if the speed of the transfer drum and the speed of the fixing unit are different and the speed of the transfer drum is different from that of the fuser when some paper still remains on the transfer drum, the paper 112 will be deflected and the recorded image will be distorted. If you try to record at different speeds of the transfer means, the peeling part 1 of the transfer drum 113
14 to the fixing device 116 must be longer than the maximum length of paper that can be used, which tends to make the device larger than necessary. In order to perform image recording under appropriate fixing conditions depending on the type and color of the recorded image, the device must be larger than necessary.The present invention takes this into consideration and appropriately varies the fixing conditions according to the paper type and purpose. It is an object of the present invention to provide a color image forming apparatus which can perform various functions and which can be miniaturized.

Means for Solving the Problems In order to achieve the above objects, the present invention includes an image forming means having at least a photoreceptor and a developing device, a transfer means for conveying the paper while transferring an image to the paper, and a A color image comprising a fixing means for fixing an image, the photoreceptor and the transfer means being in a contact state and being separated, and a paper conveyance speed of the transfer means being variable. With the above-described structure, the present invention detaches the transfer means from the photoreceptor immediately after the image transfer to the recording paper is completed, and sends the recording paper to the fixing means at a speed unrelated to the speed of the photoreceptor. The fixing means fixes the recording paper at a fixing speed determined by the type of recording paper or the color to be recorded.

Embodiment FIG. 1 is a block diagram of an embodiment of the present invention. 1 is the reading section of the digital color copying machine, and is mainly used for the original platen 2.
1, a document illumination lamp 3, a lens 4, a color line sensor 5, a drive system 6 for moving these in the sub-scanning direction for scanning, an image processing circuit (not shown), and more.
0 is the writing area of the digital color copier. 11
12 is a Se-based photoreceptor with increased sensitivity to laser light with a wavelength of 780 to 810 nm, and is rotatably supported in the direction of arrow A. 1 Charger 26 indicates a laser beam light. 20 is a laser optical section, and a laser beam 26 is emitted from a laser oscillation block 21, and a polygon scanner 2
2. Photoconductor I via lens system 23 and mirrors 24 and 25
Even if the scanning light of the laser beam light 26 is configured to scan over I, a part of the scanning light of the laser beam light 26 is reflected by the mirror 27 and irradiated onto the starting edge detection sensor 28 . There is a developing section 30 on the right side of the photoreceptor 11, and along the periphery of the photoreceptor 11, from the top, there are a Y developer 31 for developing yellow color, an M developer 32 for developing magenta color, and a C developer for developing cyan color. A developing device 33 (hereinafter collectively referred to as a color developing device) and a developing device 34 for developing black color are arranged. Y developer 31, M developer 32
, C developing device 33 is a non-contact developing device using non-magnetic one-component toner, and is capable of developing the photoreceptor 11 while flying the toner without contacting it.
is a developing device that uses a two-component developer and develops while bringing the developer into contact with each other. Each developing device can take two positions, a position close to the photoreceptor 11 and a position away from it, and by rotating the eccentric cams 35 to 38, the Y developing device 31, the M developing device 32, The rear part of the C developing device 33 is pushed and it moves horizontally to approach the photoreceptor (-K developing device 3
4 rotates counterclockwise about the shaft 39 and approaches the photoreceptor, allowing development. Figure 1 shows M developer 3.
The case where only No. 2 is in a developable state is shown.

40 is an eccentric cam 35, 36, 37, 38 and a developing device 31
, 32, 33, and 34. Reference numeral 50 denotes a paper feed unit that can feed paper one sheet at a time from each of cassettes 51 and 52 and manual paper feed unit 53, and this figure shows a case where paper 56 is fed from cassette 51. . The paper 56 is fed to the lower surface of the photoreceptor 11 via the registration rollers 54.
62 and movable rollers 67 and 68 can take two states: a state in which a portion of the semiconductive belt 63 is lightly pressed against the photoreceptor 11, and a state in which it is separated from the photoreceptor 11. Even if it is possible and the movable rollers 67 and 68 move in the direction of arrow B, the movable rollers 67 and 68 must move within the range shown by the roundworm line in order to make the belt 63 and the photoreceptor 11 come into contact with each other or be separated from each other. Although the solid line in this figure shows the state in which the belt 63 is separated from the photoreceptor 11, when the belt 63 is in pressure contact with the photoreceptor 11, it moves at the same speed as the outer peripheral speed of the photoreceptor 11. 11, it moves at the same speed as, for example, the moving speed of the recording paper 56 required by the fixing unit 70, regardless of the speed of the photoreceptor 11. 64 is a second charger for transferring the belt. 6
A cleaning blade 65 is used to clean the toner remaining on the belt. I am in contact with 63. A collection box 66 is arranged below the cleaning blade 65. 69 is a third charger that sprinkles negative corona when the paper 56 is separated from the belt 63. Reference numeral 70 is a fixing unit, and a heat roller 72 heated by a fixing lamp 71 and a rubber roller 73 are rotatable while being in pressure contact with each other, and a paper ejection roller 7 is provided at the rear of the heat roller 72 and a rubber roller 73, which are in pressure contact with each other.
5 and a paper discharge tray 76 are provided. Reference numeral 80 denotes a cleaner which can assume two states, a state in which the fur brush 81 is in light contact with the photoreceptor 11, and a state in which it is separated from the photoreceptor 11, and is rotatable in the direction indicated by the arrow. Although this figure shows the state in which it is in contact with the photoconductor II, a collection roller 82 is further provided rotatably while in contact with the fur brush 81.The fur brush 81 and the collection roller 82 each have a negative voltage with respect to the photoconductor 11 is applied. A collection screw 83 is installed at the bottom of the collection roller 82, and a vibrator 84 is connected to the front end of the collection screw 83, and is connected to a collection box 85 through this. A fourth charger 86 for positively charging the toner on the photoreceptor 11 and a static elimination lamp 87 for neutralizing the photoreceptor 11 are disposed at a position facing the photoreceptor at the bottom of the reach 80. 90 is the heat roller 7
2 and a motor that drives the transfer conveyance section 60.
2 are cooling fans for sucking air from the lower and upper parts of the writing section 10 and discharging it to the outside of the apparatus. Explain the action.

When the original is placed on the document table 2 and the copying operation begins,
A document is read by a reading section 1, and an image to be recorded by a writing section 10 is determined accordingly. In the writing section, signals to be recorded are input in the order of black, yellow, magenta, and cyan, and recording is performed. First, a black signal is inputted to the laser oscillation block 21; Even if the area irradiated by the laser beam 26 is uniformly charged to +850V by the charger 12 and removed to about +50V, the main scanning of the laser beam 26 on the photoconductor 11 is a polygon. Scanner 22
Sub-scanning is performed by rotating the photoreceptor 11 in the direction of arrow A, forming a latent image on the photoreceptor. When a latent image is first written on the photoreceptor, the developing unit 30 is set to develop black color, and only the K developer 34 approaches the photoreceptor 11 by the operation of the eccentric cam 38, while the other developers are in a separated state. It is in. Therefore, the latent image corresponding to the black signal formed by the laser beam 26 is developed with black toner by the developing device 34 and passes through other developing devices without being affected. At this time, the timing of contact and separation is controlled so that the developing device 341;t, g light body 11 moves close before the exposure by the laser beam 26 is started and moves away after development. The image developed with black toner reaches the transfer conveyance section 60 as the photoreceptor 11 rotates (at this time, the movable rollers 67 and 68 are in the position shown in FIG. 1 in the transfer conveyance section 60, and the belt 63 is The fur brush 81 is spaced apart from the surface of the photoreceptor 11, allowing the image to pass through without being disturbed.Furthermore, the fur brush 81 is separated from the photoreceptor 11 at a position slightly rotated counterclockwise around the axis of the collection screw 83. Here, too, the black toner image passes through without being disturbed and passes under the first charger 12 again. The area without toner is recharged from +850V.
, Even though the part with the toner is apparently charged to +850V, the leading edge of the black toner image is recharged and the laser beam light 2 is applied again.
When reaching the irradiation position 6, the laser beam 26 is modulated according to the yellow signal and is exposed from above the black toner image on the photoreceptor 11, but the leading edge of the image is aligned and the scanning speed is constant. Even if the latent image caused by the yellow signal and the latent image formed by the yellow signal coincide with each other in position, the latent image formed by the yellow signal? ! This time, only the Y developing device 31 of the developing section 30 is close to the photoconductor 11, and the other developing devices are separated from each other, so that only the yellow toner is used for development, and a yellow toner image is formed on the photoconductor in addition to the black toner image. At this time, Y developer 3
], the timing of contact and separation is controlled so that the photoconductor 11 moves close before the laser beam 26 starts to be exposed and moves away after development. Without disturbing the toner image t,% or less, recharging in the same manner Latent image type development by magenta signal Magenta development Recharging Latent image type polishing by cyan signal Cyan development is repeated.

At this time, the yellow toner and magenta toner pass through the laser light. Can be layered with cyan toner. After the last cyan toner image is formed, just before the leading edge of the toner image reaches the transfer conveyance unit 60, the transfer conveyance unit 60 is brought into a state of being lightly pressed against the photoreceptor 11, and the leading edge of the toner image and the paper 56 are brought into contact with each other. The paper 56 is fed by the registration roller 54 so as to enter between the photoreceptor 11 and the belt 63 at the timing when the leading edges match, and then the toner image is transferred to the paper 56 by the electric field generated by the second charger 64. Inside storage paper 56 is on belt 63
However, since the curvature of the roller 62 is large, it separates from the belt 63 and enters the fixing section.
At this time, the distance between the transfer position and the fixing section is set to be slightly larger than the maximum paper length, and the belt 63 is separated from the photoreceptor 11 immediately after the trailing edge of the paper passes the transfer position. The paper conveyance speed is motor 90.
At the leading end of the belt, the paper 56 is separated from the belt.
In order to prevent the toner image on the paper 56 from being disturbed due to the peeling charge generated during the separation, a negative corona is sprinkled from the top by the third charger 69. It is positively charged by the fourth charger 86 which starts operating immediately before the fur brush 81 and the photoconductor 11 are brought into contact with each other, and the fur brush 81 is slid into contact with the photoconductor 11 at the same time. The electric field is transferred to the fur brush 81. Furthermore, the toner in the fur brush 81 is transferred to the collection roller 82 due to the electric field applied between the collection roller 82 and the fur brush 81 and is transferred to the collection screw 83.
The surface of the photoreceptor 11 is cleaned by the vibrator 84 and placed in the collection box, and the static electricity is removed by the static elimination lamp 87, and the photoreceptor 11 is returned to its initial state and ready for the next copy. .

On the other hand, a small amount of toner accumulated on the belt 63 of the transfer conveyance section 60 due to operational errors or normally is cleaned by a cleaning blade 65 and collected in a collection box 6.
Dropped within 6.

The above is an overview of the overall configuration and operation of a digital color copying machine to which the present invention is applied.4 As described above, according to this embodiment, when an image has many black characters, which are common in business documents, normal fixing is performed and glossy color copying is performed. In the case of picture-like images or OHP, it is possible to selectively create glossy images with good light transmittance by reducing the fixation, depending on the purpose, and also minimize the size of the equipment. It is possible to provide a color image forming apparatus that can perform

In this embodiment, the transfer means uses a batch transfer method. According to the present invention, as described in detail, it is possible to vary the speed by separating the transfer unit from the photoreceptor. By separating the transfer device from the fixing device and making the speed of the transfer conveyance variable, low-speed fixing can be performed immediately after the transfer operation is completed, so the distance from the transfer means to the fixing device can be kept to the minimum necessary length, and the device The effect on miniaturization is very large1.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram of a conventional image forming apparatus. 1...Reading question 2...Writing i 11...
・Photoreceptor 30...Developing plate 31...Y developing device 32
...M developing device 33...C developing device 34...K developing device 60...transfer conveyance plates 61, 62...rollers,
67, 68...Movable roller, 70...Fuser

Claims (2)

[Claims] (1) An image forming means having at least a photoreceptor and a developing device, a transfer means for conveying the paper while transferring a surface image onto the paper, and a fixing means for fixing the image on the paper, and the photoreceptor 1. A color image forming apparatus, wherein the transfer means and the transfer means have a state in which they are in contact with each other and a state in which they are separated from each other, and a paper conveyance speed of the transfer means is variable. (2) The color image forming apparatus according to claim 1, wherein the transfer means uses a multicolor image batch transfer method.