JPS63125960A - Color image recorder equipped with automatic supply function for developer - Google Patents

Abstract

PURPOSE:To securely prevent a development irregularity and a color slurring from being caused by detecting whether or not toner needs to be replenished and replenishing toner automatically to a developer pool provided to a developing device for a constant period from the end timing of color development when the toner needs to be replenished. CONSTITUTION:When it is judged as a result of toner concn. detection that toner needs to be replenished, a toner replenishing signal is supplied to developing devices 5-7. Namely, the toner replenishing signal is supplied to a driving circuit 48 for a toner replenishing roller 28 provided to a developing device and a toner replenishing roller 28 is driven nearly for the constant period of one turn of an image formation body 1 after the development of each color separated image is completed. When the toner needs to be replenished at the end of the development of final color, the toner is supplied during the postrotation process of the developing process, so the postrotation process time is so varied in this case so that a constant amount of toner is all replenished to the developer pool.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides an automatic developer replenishment function suitable for application to a simple electrophotographic color copying machine having a plurality of developing devices. The present invention relates to a color image recording device.

[Background of the Invention] A color copying machine attempts to record a color image by separating color information into approximately three to four types of color information.

An example of such a simple electrophotographic color copying machine is shown in FIG. However, in this example, the color information is separated into three colors and developed.

In FIG. 7, 1o is an example of a main part of a color copying machine, and 1 is a drum-shaped image forming member (photosensitive drum, hereinafter simply referred to as drum), and its surface is coated with photoconductive material such as selenium Se. A photoreceptor surface layer is formed so that an electrostatic image (electrostatic latent image) corresponding to an optical image can be formed.

The following members are sequentially arranged on the circumferential surface of the drum 1 in the direction of rotation thereof.

The surface of the drum 1 is uniformly charged by a charger 2. The surface of the charged drum 1 is no longer subjected to image exposure (the light image is shown by 4) based on each color separation image.

After image exposure, the image is developed by a predetermined developing device.

The developing devices are arranged in a number corresponding to the color separated images.

In this example, a developing device 5 filled with a red toner developer, a developing device 6 filled with a blue toner developer,
The developing devices 7 filled with a black toner developer are arranged facing the surface of the drum 1 in this order in the rotational direction of the drum 1.

The developing devices 5 to 7 are sequentially selected in synchronization with the rotation of the drum 1. For example, by selecting the developing device 7, a black color separation image, that is, a normal black and white image can be developed.

A pre-transfer charger 9 and a pre-transfer exposure lamp 11 are provided on the developing device 7 side.
These make it easy to transfer a color image onto recording paper (transfer paper, etc.) P. The pre-transfer charger 9 and the pre-transfer exposure lamp 11 are provided as necessary.

The color image developed on the drum 1 is transferred onto a recording paper P by a transfer device 12.

The recording paper P on which the transfer has been completed is subjected to a fixing process by the fixing device 13 at the subsequent stage, and is then discharged.

Note that the static eliminator 14 includes one or a combination of a static eliminator lamp and a corona discharger for static elimination.

The cleaning device 15 is composed of a cleaning blade and a fur brush, and is used to remove residual toner adhering to the surface of the drum 1 after the color image has been transferred.

As the charger 2 described above, a scorotron corona discharger or the like can be used. This is because stable charging can be applied to the drum 1 with less influence from previous charging.

As the image exposure, image exposure obtained by an optical scanning device such as a laser beam scanner can be used.

When using such an optical scanning device, a semiconductor laser can be used as the light source of the image recording device. This is because semiconductor lasers are small and inexpensive, and can also record clear color images.

FIG. 8 shows an example of the developing device 5 used in the above.

In the figure, 21 indicates a housing, and a cylindrical sleeve 22 is rotatably housed within this housing 21. A magnetic roll consisting of 8 N and S poles is provided inside the sleeve 22. A layer regulating piece 24 is provided on the outer peripheral surface of the sleeve 22.
is pressed against the sleeve 22, and the layer thickness of the developer adhering to the sleeve 22 is regulated to a predetermined thickness. The predetermined thickness is 1
It refers to a predefined value between 0 and 500 um.

Inside the housing 21, first and second agitating members 25, 26 are provided. The developer reservoir in the developer reservoir 29 is connected to the first agitating member 25, which rotates in a counterclockwise direction;
The developer mixture is sufficiently stirred and mixed by the second stirring member 26 which rotates in the opposite direction to the first stirring member 25 so as to overlap with each other, and the mixed developer is transferred to the sleeve 22 which rotates in the opposite direction. Due to the rotational conveyance force of the magnetic roll 23 and the magnetic roll 23, it is generally fed and attached to the surface of the sleeve 22.

The electrostatic latent image formed on the image forming body 1 can be completely developed in a non-contact state by the developer adhered to the image forming body 1.

Note that during development, the development bias signal supplied from the power source 30 is completely applied to the sleeve 22.

The developing bias signal consists of a DC component from the power source 30 selected to have approximately the same potential as the potential of the non-exposed portion of the image forming body 1, and an AC component superimposed thereon. As a result, only the toner T in the developer on the sleeve 22 selectively migrates to the surface of the image forming member 1, which has been made into a latent image, and adheres to the surface of the image forming member 1, and development processing is performed. Become.

Note that 27 is a toner container, and 28 is a toner supply row. 31 indicates a development area.

When the toner density becomes low, the toner supply roller 28
By rotating the toner T, a predetermined amount of toner T is supplied to the developer reservoir 29.

[Problems to be Solved by the Invention] By the way, in a color image recording device configured as described above, when the copy density becomes less than a predetermined density, toner is replenished to maintain the density of the recorded image at a constant value. There is a need to.

Conventionally, when the copy density falls below a predetermined value, toner is automatically replenished. Automatic replenishment is generally executed immediately after it is detected that the copy density is below a predetermined value.

Therefore, toner replenishment may be performed during the development process.

However, if toner is completely replenished during development, the image density may change after toner replenishment.

That is, there is a possibility that uneven development may occur.

Further, depending on the structure of the developing device, vibrations caused by the operation of the toner replenishing member may be transmitted to the drums 11 fl and 11, and the current image may be disturbed accordingly.

This significantly degrades the copy image quality. Particularly, color shifts occur in color images.

Therefore, the present invention solves these conventional problems with a simple structure, and provides a color image with an automatic developer replenishment function that replenishes toner after each development process is completed. This paper proposes a recording device.

[Technical Means for Solving the Problems 1] In order to solve the above-mentioned problems, the present invention has a plurality of developing devices each containing a plurality of different toners, and uses these developing devices to In a color image recording device that develops a color image by performing a development process, the system detects the presence or absence of toner replenishment, and when it is necessary to replenish toner, it supplies the developer to the developer for a certain period of time from the end of color development. This device is characterized in that toner is automatically replenished into a developer reservoir provided therein.

[Operation] When the toner density obtained from a predetermined image area is below a certain level, toner is automatically replenished into the developer reservoir provided in the developing device over a certain period of time from the end of color development. .

This makes it possible to reliably prevent uneven development, color shift, and the like.

[Embodiment] Next, an example of an image recording apparatus having an automatic developer replenishment function according to the present invention will be described in detail with reference to FIG. 1 and subsequent figures.

In the present invention, a control system used for various controls of the apparatus main body is used as means for detecting toner concentration and determining toner replenishment timing.

In this example, a microcomputer used in a system control section provided for controlling the operating state of a color copying machine is used.

FIG. 1 shows an example of the main parts of the control system, in which 41 is a microprocessor (CPU), 42 is a ROM in which a control program is stored, and 43 is a RAM for storing various control data.

Command data from various keys provided on the operation/display unit SO shown in FIG.
, and predetermined arithmetic processing can be executed.

Further, the CPU 41 generates a tonercon batch signal for detecting toner density. This patch signal causes a predetermined pattern of a tonercon batch image to be developed on the drum 1, and the toner density level of this patch image can be detected by a light reflection type sensor (not shown).

This toner density (No. 2 (toner density information) is determined by the CPU again.
When the toner concentration is below the specified value, a command signal from the CPU 41 is sent to the I10 port 47.
The drive circuit 4 of the toner replenishing roller 28 shown in FIG.
It can be supplied to 8. As a result, the toner supply roller 28
is rotated and a certain amount of toner T is fed to the developer reservoir 29 .

FIG. 2 shows an example of the key layout of the operation/display section 50.

Reference numeral 51 denotes a copy start button, which copies only the number of copies set on the numeric keypad 52, and the set number of copies is displayed on the display section 5.
3.

Copying can be performed at any density by operating the copy density selection button 55. The selected copy density is displayed on the display section 56.

Numeral 61 is a copy mode switching button, and each time the button is pressed, multicolor mode and monocolor mode are alternately selected. When the monochrome mode is selected, any color can be selected using three color selection buttons 62 to 64.

Buttons 62 to 64 for color selection when multicolor mode is selected
If you operate , the specified color will be canceled.

By the way, the above-mentioned toner density is detected with reference to a certain specific image area. Therefore, as shown in Figure 3A, patch No. 48 for concentration detection (for example, 8
(an image signal corresponding to an image area of size o+) is used.

This patch signal can be sent out in synchronization with the start timing of each development process of the color separation image, and the toner density is detected after a predetermined period has elapsed since the patch signal was sent. Therefore,
After a predetermined period of time has elapsed, each toner density is detected by the toner density detection signal shown in the third diagram.

Note that FIG. 3 is a timing chart in a multicolor mode in which color recording is performed using all three colors,
Image exposure based on each color separation image is performed each time the image forming body 1 rotates (FIG. 8), and development processing is completed in synchronization with this image exposure (FIG. 8C).

Then, when it is determined that toner needs to be replenished as a result of the toner concentration detection, a toner replenishment signal is supplied to the developing devices 5 to 7. That is, a toner replenishment signal is supplied to the drive circuit 48 of the toner replenishment roller 28 provided in the developing device.
After the development of each color separation image is completed, the toner replenishing roller 28 is driven for a certain period of time, for example, as shown in FIG. 3E, for one rotation of the image forming body 1.

As a result, the corresponding developer reservoir 29 is replenished with a predetermined amount of toner. FIG. 3 shows a detection situation in which toners of all colors are replenished.

In addition, in FIG. 3, if it is necessary to replenish toner after the final color development is completed, toner replenishment will be performed during the rotation process after the development process. In some cases, the post-rotation processing time can be changed so that a certain amount of toner can be completely replenished into the developer reservoir.

Such processing for changing the post-rotation processing period is also performed in a copy mode (mono-color mode) in which color recording is performed using a single color.

When a toner replenishment command is issued during continuous copying,
Toner can be replenished by inserting idle rotations at appropriate times during continuous copying.

FIG. 4 is a flowchart showing an example of a control system for toner replenishment.

When the toner density control routine is called, step 8
0, toner density detection is performed using the patch image described above. When the detected l/toner density is below the toner replenishment level, the developing color is determined (step 81).

When the color being developed is the first color, the corresponding counter N1 is incremented, and then the count value is determined (steps 82, 83). In this example, when the same detection result continues three times, it is determined that the toner concentration is below a predetermined replenishment level.

This is done in order to avoid malfunctions in concentration detection.

Therefore, when the count value of the counter for the first color reaches N1=3 after several toner detection operations, the toner replenishment flag for the first color is set, and thereby toner replenishment is executed (step 84). . However, if there is no toner in the toner container 27 or the remaining amount is small, the required amount of toner will not be replenished even if the toner replenishment operation is repeated.

Therefore, in this example, in step 85, it is checked whether the count value of the counter N1 is a predetermined value, for example 10, and when N1=10, toner replenishment is stopped and the 1 toner remaining flag is set. (Steps 86 and 87).

The toner remaining amount flag is also used as a display signal indicating "out of toner", and this is displayed on the operation/display unit 50.

Similar toner density detection and replenishment operations are performed for the second and third colors as well.

Steps 91 to 97 show the second color toner concentration detection operation and toner replenishment operation.

In this case as well, the count value of the second color counter N2 is checked in steps 93 and 95. Then, when N2=3, the second color toner replenishment operation is started.

When N2 = 10 is detected, the toner replenishment operation is stopped, and at the same time, the remaining amount of toner and "No Toner" are displayed.
will be displayed.

Steps 102 to 107 show the third color toner concentration detection operation and toner replenishment operation.

In this case as well, toner replenishment, toner remaining amount, and display of "out of toner" are executed by checking the counter N3 for the third color.

When the toner density reaches or exceeds the toner replenishment level by replenishing toner corresponding to each color, step 110
to move to. And when the first color is being developed,
In addition to clearing counter N1, if necessary,
Control is performed to turn off the "No Toner" display (steps 111 and 112).

When the second color is being developed, control is performed to clear the counter N2 and turn off the "Toner Out" display (steps 113 to 115).

Similarly, if it is neither the first color nor the second color, it is the third color, so in this case as well, control is performed to reset the counter N3 and turn off the "out of toner" display (step 116). .117).

By the way, when the toner replenishment flag is set in the step of FIG. 4, the toner replenishment subroutine 120 of FIG. 5 is called and the toner replenishment process is executed.

In this case, it is checked in steps 121, 131, and 141 which color the toner replenishment flag is.

If it is the toner replenishment flag for the first color, the timing at which the development of the first color ends is checked, and when the development is completed, toner replenishment for the first color can be started and whether a predetermined period of time has elapsed after the start is checked. Checked (
Steps 122-124). The timing chart is as shown in FIG.

The predetermined time is normally selected to be less than the time required for one rotation of the drum.

When a predetermined period of time has elapsed, toner replenishment is stopped, the toner replenishment flag is reset, and the process returns to the main routine (steps 125 and 126).

2. Even when the toner replenishment flag is for a color, the toner replenishment flag is reset after toner replenishment processing and stop processing are executed by the same processing steps as described above (steps 131 to 136).

Even when the toner replenishment flag is for the third color, the toner replenishment flag is reset after the toner replenishment processing and stop processing are executed as described above (steps 141 to 14).
6).

Although it is not directly related to the present invention, an example of the above-mentioned mode switching, that is, copy mode switching between multicolor mode and monochrome mode, will be shown below. Mode switching in this case is controlled by a microcomputer.

When the copy mode switching button 61 is operated, a processing routine 70 for copy mode switching shown in FIG. 6 is called.

That is, when the copy mode switching button 61 is operated, this is determined in step 71, and then the state of the color copy mode is determined (step 72). Since the color copy mode is switched between multicolor mode and monocolor mode using the mode switching button 61, it is checked in this step which mode the color copy mode was before this button 61 was operated. Ru.

This mote determination is performed based on the presence or absence of the multicolor mode flag. When the multicolor mode flag is 1, the previous color copy mode is multicolor mode, so in that case, it is necessary to invert the color copy mode to monochrome mode.

On the other hand, when the multicolor mode flag is 0, the previous color copy mode was monochrome mode, so in that case, the color copy mode is reversed to multicolor mode.

For this reason, when the mode flag is 1, in this example, only the black flag is set to invert to monochrome mode (step 73).

That is, in the monochrome mode, the black flag is first set to 1 so that black copying is performed unconditionally, that is, the normal black and white copying mode. Thereafter, a display panel (not shown) such as an LED provided on the black selection button 64 is controlled to be lit (step 74). This makes it possible to visually recognize that black is currently selected in the monochrome mode.

After controlling the black display element to be lit, the mode flag is reset (step 75). This is done so that when the next mode selection operation is performed, by operating the copy mode switching button 61, the multicolor mode can be immediately selected in place of the previously selected monochrome copy mode. .

On the other hand, when it is confirmed in step 72 that the multicolor mode flag is O, the golden flags from red to black are set, and the color selection buttons 62 to 64 are turned on. Thereafter, the multicolor mode flag is set (steps 76 to 78), and the copy mode switching control routine returns to the main control routine.

In addition, since the color copying machine is illustrated above as an example of a color copying machine, even in multi-color mode, only the three colors red, blue, and black can be selected as the colors that can be copied, but other colors can also be selected.・A color copying machine capable of copying ・or a color separation image different from this example (for example,
It is easy to understand that the present invention can also be applied to a color image recording apparatus that performs development processing based on color separation images of complementary colors.

[Advantageous Effects of the Invention 1] As explained above, in this invention, the toner replenishment start timing is selected to be the development end timing of each color, which eliminates the conventional disadvantages such as uneven development and color misregistration. You can definitely wipe it out.

In addition, since toner replenishment is performed immediately after the completion of development processing for each color, drum 1 is not rotated idly for toner replenishment, so there is no reduction in the efficiency of use of the device. .

Therefore, the present invention is extremely suitable for application to a color image recording apparatus or the like that can select a predetermined color as described above.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a control system showing an example of the essential parts of a color image recording device according to the present invention, FIG. 2 is a plan view showing an example of an operation/display section, and FIG. 3 is a diagram for explaining the operation of the present invention. FIG. 4 is a flowchart showing an example of a toner concentration detection and replenishment processing routine, FIG. 5 is a flowchart showing an example of a toner replenishment processing routine, and FIG. 6 is an example of a control program for copy mode switching. 7 is a block diagram showing an example of a color copying machine, and FIG. 8 is a sectional view of essential parts showing an example of a developing device used therein. 5 to 7...Developing device 1...Image forming body (drum) 27...Toner container 28...Toner replenishment roller 41...CPU 48...Roller drive circuit 50...Operation Display section 61...Copy mode switching buttons 62-64...Color selection buttons Figure 6, Section 8, =5. : Engineering! -I Kinuta 13

Claims (4)

[Claims] (1) In a color image recording device that has a plurality of developing devices each containing a plurality of different toners and develops a color image by performing development processing for each color using these developing devices, the toner Detects the presence or absence of toner replenishment and when it is necessary to replenish toner.
A color image recording device equipped with an automatic developer replenishment function, characterized in that the toner is automatically replenished into a developer reservoir provided in a developing device over a certain period of time from the end timing of color development. (2) An automatic developer replenishment function according to claim 1, wherein the presence or absence of toner replenishment is determined based on the toner density level detected from a predetermined image area. color image recording device. (3) The automatic developer replenishment function according to claims 1 and 2, characterized in that the end timing of the development process for each color is used as the end timing of the color development. A color image recording device equipped with (4) A color equipped with an automatic developer replenishment function according to claims 1 and 2, characterized in that the plurality of colors include three colors: red, blue, and black. Image recording device.