JPH0469676A - Multicolor image forming device - Google Patents

Abstract

PURPOSE:To improve transfer efficiency by previously sticking translucent powder to an intermediate transfer body. CONSTITUTION:A belt cleaner 9 and a developing unit 10 are provided on the intermediate transfer body 8. Transparent toner is housed in the developing unit 10, and its attaching frame 94 can be revolved so as to be separated from a transfer belt 81, while centering a supporting shaft 93. First, a solenoid 96 is turned on, the attaching frame 94 is revolved counterclockwise, and a sleeve roller 101 and a brush roller 91 approach and rotate the transfer belt 81 to uniformly stick the transparent toner to the belt 81. Simultaneously, the roller 91 is rotated to clean the belt 81. Then, a transfer charger 4 is turned on, a toner image on a photosensitive drum 6 is transferred to the belt 81, the solenoid 96 is turned off before the top end of an image on the belt 81 reaches the roller 91, and the attaching frame 94 is revolved in the direction of the rotation of the supporting shaft 83, and retreated from the belt 81, by the spring 95. Thus, the toner image transferred on the belt 81 is not disturbed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a multicolor image forming apparatus such as a full color copying machine that forms a full color image by performing multiple transfer steps on an intermediate transfer member such as a transfer belt. In particular, the present invention relates to a technique for improving transferability from an intermediate transfer member to paper.

[Prior Art] A full-color copying machine using an intermediate transfer member such as a transfer belt is known as a conventional multicolor image forming apparatus. This allows the original image to be copied to be yellow (Y), magenta (M
), cyan (C), and black, electrostatic latent images of each color are formed on a photoreceptor one color at a time, starting with yellow, and then developed into a toner image. The developed toner image is transferred one color at a time to an intermediate transfer member such as a transfer heald, and these steps are repeated four times to form a full-color image consisting of up to three layers on the intermediate transfer member, and then transferred to paper, etc. The image is transferred all at once to the image carrier.

[Problem to be solved by the invention]

In full-color copying machines that use intermediate transfer bodies, it is an important issue to improve transfer efficiency during batch transfer. - If the transfer efficiency during batch transfer is poor, a portion of the toner image first transferred to the intermediate transfer member, that is, the bottom layer toner image remains on the intermediate transfer member. For example, when the colors are transferred to the intermediate transfer body in the order described above, a portion of yellow remains on the intermediate transfer body. When the toner image remains on the intermediate transfer member, the color components (for example, yellow component) of the remaining toner image decrease, resulting in a problem that the hue of the full-color image transferred to the paper becomes different from the original image.

The present invention was made in view of the above circumstances, and it is possible to transfer the toner image on the intermediate transfer body by attaching a transparent powder to the intermediate transfer body before transferring the image to the intermediate transfer body. Transfer as much as possible to the image carrier to improve transfer efficiency.
To provide a multicolor image forming device capable of forming a color image with hues faithful to the original image.

[Means to solve the problem]

A multicolor image forming apparatus according to the present invention includes a plurality of developing means disposed around a photoconductor, containing developers of mutually different colors, and developing latent images formed on the photoconductor according to each color. and an intermediate transfer body that transfers each color of the developed image multiple times to form a multicolor image, and transfers the multicolor image formed on the intermediate transfer body to an image carrier at once. In the image forming apparatus, an adhesion means is provided upstream of the transfer position of the intermediate transfer body and attaches a translucent powder to the intermediate transfer body, and the adhesion means causes the powder to adhere to the intermediate transfer body. and a control means for controlling (n).

[Effect]

In the present invention, when forming a multicolor image, a light-transmitting powder is adhered to the intermediate transfer member by an adhesion means before being transferred to the intermediate transfer member, and images of each color are sequentially transferred thereon. A multicolor image is formed on an intermediate transfer member, and the multicolor image is transferred all at once to an image carrier. As a result, the lowermost layer has a transparent powder attached to it instead of the initially transferred image, so the image transferred from the photoconductor to the intermediate transfer body during batch transfer does not remain on the intermediate transfer body. Transferred to a carrier.

〔Example〕

Hereinafter, the present invention will be explained in detail based on drawings showing embodiments thereof.

FIG. 1 is a schematic vertical sectional view showing the structure of a digital full-color copying machine which is a multicolor image forming apparatus according to the present invention, in which A is an image league section, B is an image forming section, and C is a multicolor image forming apparatus according to the present invention.
indicates a copy paper processing system.

Image reader section A is the original glass plate]-J second]・
The scanner section 2 includes a scanner section 2 that reads an optical image of a document that has been scanned, and an optical system that projects the image read by the scanner section 2 onto a photosensitive drum 6 and exposes it to light.

The scanner section 2 is equipped with a light tX21 that illuminates the document surface through the document glass plate 1, a SELFOC lens array 22 that captures the reflected light from the document surface, and a CCD linear image sensor 23 that provides the JI'1 light that is emitted from the document surface. After the document surface data is converted into an electric signal by the CCD linear image sensor 23, it is color-separated through the polygon mirror 24 and the plane mirror 25 as a light-on/light-off signal for the laser diode F in the laser light generator 26. The images are sequentially projected onto the photosensitive drum 6 constituting the image forming section C, and exposure is performed.

The image forming section B is composed of a photosensitive tram 6, developing units 7y, 7m, 7c, 7b, intermediate transfer body 8, and other devices arranged around the photosensitive tram 6. The photosensitive drum 6 is configured to be rotationally driven in the direction of the arrow, which is the time direction, and around the photosensitive drum 6 there are charged chargers 3 located above the rotational drive range.
is arranged, and yellow, magenta, cyan, and black developing units 7y+7m, 7c,
7b are arranged in this order. The image reader section is irradiated with the color-separated optical image from the laser light generator 26, and the potential of the irradiated portion drops to form a latent image. During the first rotation of the photosensitive drum 6, a color separated light image is irradiated with a beam onto the charged photosensitive drum 6, and the developing device 7y
Yellow toner adheres to this irradiated area and is visualized as a yellow toner image, which is transferred to an intermediate transfer body 8 to be described later by application of a reverse potential by the first transfer charger 4.

Subsequently, in the second rotation, a color-separated light image is irradiated with a beam onto the charged photosensitive drum 6, and magenta toner is attached to this irradiated area and visualized, and transferred to the intermediate transfer member. Similarly, in the third rotation, cyan toner is transferred, and then in the fourth rotation, black L toner is transferred to
The latent images are sequentially attached to each latent image portion illuminated by the beam, developed, and transferred to the intermediate transfer member 8, thereby forming a full-color image.

The full-color image obtained by the four transfers on the intermediate transfer body 8 is conveyed by the second transfer charger 11 to the paper feeding case 16a in the copy paper processing system C through the transport rollers 3a, 13b, 1.3c. , 16b, and are transferred all at once onto copy paper. After a minute M in the separation charger 12, the copy paper on which the image has been transferred is conveyed to the fixing device 14 via a conveyor bell) 13d, and after fusing and fixing the toner, it is discharged 1-1/
−1,5 is discharged.

FIG. 2 is a schematic enlarged sectional view showing the structure around the intermediate transfer body 8, and FIG. 3 is a perspective view showing the structure of a heald cleaner and a developing device integrated therewith. ] It is configured using. Transfer bell I/81
For example, it is made of a dielectric composite wire, and has a structure in which it is stretched over five rollers 82 to 86 arranged in a modified pentagonal shape. The roller 82 is disposed on the downstream side of the first transfer charger 4, and is not shown;
1tIl and move in the direction not shown by the arrow. Also, the roller 83 is connected to the second transfer charger 11, and the roller 85 is connected to the brush roller 91, which will be described later! - The rollers 86 are provided facing the sleeve rollers 101, which will be described later, respectively.
Roller 84 is provided between rollers 83 and 85.

These rollers 83 to 86 are driven rollers.

In addition, the sleeve roller 86 is grounded, and the sleeve roller 1
A predetermined development contrast is obtained for 01.

A heat cleaner 9 and a developing device 10 integrated therewith are provided on one surface of the roller 86 of the intermediate transfer member 8 .

The bell I-cleaner 9 includes a brush roller 91 that comes into pressure contact with the transfer bell 1- and rotates counterclockwise to remove toner remaining on the transfer heald 81, and a collection roller 92 that collects toner adhering to the brush roller 91. ing. The brush roller 91 and the collection roller 92 are rotatably supported by a flange member of a mounting frame 94, which has an elongated member having a substantially U-shaped cross section and flange members fixed to both sides of the elongated member.

The developing device 10 houses a transparent developer, and is provided at the bottom of the mounting frame 94. The developing device 10 has a brushing roller 102 for stirring and conveying the transparent toner, and a sleeve roller 101 for uniformly depositing the conveyed transparent 1-toner on the transfer heald 81.

A developing bias voltage is applied to the sleeve roller 101 by a power source (not shown), and as described above, the sleeve roller 86
A predetermined development contrast] and last can be obtained between the two.

(The 1J frame 94 can be rotated about the support shaft 93 to move toward and away from the transfer heald 8I,
It is biased clockwise (away) by springs 95, 95 whose ends are locked on both sides.

The other end of the spring 95.95 is attached to the twin frame of the copying machine (not shown). =t 4 is spelled. Also take (-1
A spool for a solenoid 96 is installed on one side of the frame 94 to drive the frame 94 in rotation, and as the spool advances and retreats, the I frame 94 rotates and moves away from the transfer heald 81. or contact.

Each device configured as described above is controlled by a control unit 1 using a computer and one microphone installed approximately in the center of the copying machine.
This is done by 00. That is, the control unit 100 outputs control signals to each device based on instructions from an operator by operating various keys on an operation panel (not shown) provided on the second side of the copying machine and detection signals described later. do. Further, the control unit 100 is given a detection signal from a detection means such as a sensor (not shown) installed in each device.

Next, the operation of the equipment around the intermediate transfer body 8 will be explained.

FIG. 4 is a flowchart showing the control details around the intermediate transfer member 8 by the control unit 100, and FIG. 5 is a timing chart showing the relationship between the leading edge position of the image and the operation of each device.

First, when the number of copies N is entered manually on the operation panel, it is substituted into the count variable X (step 1ll).
, then turn on the solenoid 96, move the sprue in and out,
The mounting frame 94 is rotated counterclockwise to bring the sleeve roller 101 and brush roller 9I closer to the transfer heald 81 (step 2). Then, a bias voltage is applied to the sleeve roller 101 by a power supply (not shown), and the sleeve roller 101 and the hexagonal roller 102 are rotated to uniformly adhere the transparent toner to the transfer bell I-81, and the brush 11-ra 91 is rotated. The transfer heald 81 is cleaned (step 13). Then, the first transfer charger 4 is turned on, and at the timing when the leading edge of the Y l-ner image on the photosensitive l/ram 6-L arrives on the first transfer charger 4,
Step I4 to transfer the +-toner image to the transfer belt 81
), turn off the solenoid 96 at the timing before the leading edge of the transfer image reaches the brush roller 91 (Step #5), and turn off the mounting frame 94 with the spring 9
5, the transfer belt 81 is rotated around the support shaft 93 and retracted from the transfer belt 81. As a result, the transfer bell l-81-1
The Yl-ner image transferred to - is not disturbed. Subsequently, each time the leading edge of the image reaches the first transfer charger 4 again, the 1-toner images of M, C, and B are transferred to the photosensitive tram 6.
to the transfer belt 81 (steps 16 to 118), and a full-color toner image is formed on the transfer belt l-81-. and second transfer charger 11
is turned on, and at the timing when the leading edge of the full-color toner image reaches the second transfer charger 11, the paper feed
．． A full-color toner image is transferred onto a copy sheet supplied from 6a or 16b, separated by a separation charger 12, conveyed to a fixing device 14 by a conveyance bell) 13d, and after melting and fixing, is discharged to a discharge tray I5.

Then, the count variable X is decremented by 1 in step 1.
110), whether or not count variable X is 0 in step old I;
That is, it is determined whether or not the input number of copies has been copied, and if there are still copies remaining, the first transfer charger 4 is turned off at a predetermined timing, and the solenoid F95 is turned on. Step #12) and Step 113 are performed. Go back and repeat the operation from there, and when the copying is completed, return to the first page. The second transfer chargers 4 and 11 are respectively turned off at predetermined timings, and the process proceeds to the next step.

Before transferring the YI-ner image to the transfer heald 8I, as shown in FIG. does not remain on the transfer heald 81, and an image with a color tone faithful to the original image can be obtained.

In this embodiment, a digital copying machine is used as an example of a multicolor image forming apparatus, but the present invention is not limited to this, and can be applied to copying machines such as Analog I7G2, transfer belts, etc. of laser color printers, etc. Needless to say, the invention can be applied to all multicolor image forming apparatuses that use intermediate transfer bodies.

〔effect〕

As explained above, in the present invention, a translucent powder was deposited on the transfer belt 1L of the intermediate transfer member in advance, and a multicolor image was transferred thereon. There is no residual image of the color originally transferred to the intermediate transfer body, and the transferred image can faithfully reproduce the hue of the original image without losing the color balance, producing an equivalent effect.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical sectional view showing the configuration of a digital full-color copying machine which is a multicolor image forming apparatus according to the present invention;
Fig. 2 is a schematic enlarged sectional view showing the structure around the intermediate transfer body, Fig. 3 is a perspective view showing the structure of the heald cleaner and developing unit, and Fig. 4 is a flowchart 1 showing the control details around the intermediate transfer body. ~, Figure 5 is a timing chart thereof.

Claims (1)

[Scope of Claims] 1. A plurality of developing means disposed around a photoreceptor, containing developers of mutually different colors, and developing latent images corresponding to the respective colors formed on the photoreceptor; A multicolor image forming apparatus includes an intermediate transfer member that transfers each color of an image multiple times to form a multicolor image, and transfers the multicolor image formed on the intermediate transfer member to an image carrier at once. an adhesion means provided upstream of the transfer position of the intermediate transfer body for adhering translucent powder to the intermediate transfer body; and controlling adhesion to the intermediate transfer body by the adhesion means. A multicolor image forming apparatus comprising: a control means.