JPS623269A - Image recording device - Google Patents

Abstract

PURPOSE:To maintain set toner concentration stably for a long period by providing the 1st supply control means which controls the supply of a developer according to the detection result of concentration and the 2nd supply control means which controls the supply of the developer according to the counting result of print dots. CONSTITUTION:The value (j) of a counter which counts the number of times of supply by the 1st supply control means 11 is counted up to calculate the total amount A of supply by the 1st supply control means 11. Then, the initial amount H of toner in a hopper 1 is compared with the total amount A; when H<=A, it is judged that there is no toner and a warning display is made on the display part of an operation part to finish control. When H>A, supply control by the 2nd supply control means 21 is started and the output of ATR 10 is suppressed between an upper-limit and a lower-limit set value and the output Ni of a counter 22 which counts print dots forming an image is read out of an image signal fv of the 1st sheet, so that toner consumption Ti is calculated by a calculating circuit 23. Consequently, output images which are stable for a long period are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image recording apparatus that visualizes a latent image formed by electrophotography as a T+- image. ,
・、・I [Conventional technology]
・(X! Conventionally, the development of the developing means used in this type of device
'.

;l As for the placement method, polyester resin toner and
; 4 Two-component development method mixed with iron powder and poly varnish
There is a set of l-component developing power that develops only with chill-based resin toner.

Among these, ・ Two-component development method ``'''' t1 Developing operation 90
・The toner concentration in the developer fluctuates due to a decrease in toner in the developer or an increase in toner. If the toner density is low, the image density on the recording material (recording paper) will be thin, blurred, or even disappear, and if the toner density is high,
Fog, etc. will occur in non-image areas. In order to overcome this point, □Conventionally, the following (1)
), A method of controlling the toner concentration in the developer using the method shown in (2) has been proposed and implemented.

(1) When the number of rotations of the photoreceptor during image formation reaches a predetermined number of rotations, a predetermined amount of toner is replenished.

(2) A method of directly detecting the p-toner concentration in the developer in the developing device, and replenishing a predetermined amount of toner when the detection signal falls below a predetermined level.

[Problem that the invention seeks to solve]

However, in method (1) above, regardless of the type of recorded image (blackening rate), the toner density may be over or under due to constant replenishment, resulting in the recorded image being too light or too dark, resulting in poor image output. Not stable.

In addition, in method (2), replenishment control is easy because the toner concentration in the developer is directly detected, but highly accurate detection is difficult, and toner is not replenished until the toner concentration reaches a certain level. It will only be replenished once it reaches that level or below. This causes the toner concentration in the developer to change drastically, and when the same image is printed continuously, the density of the first output image and the subsequent output image differs, resulting in a light image and a dark image. It will be output. This is because multi-color, color (single-color (two or three or more colors), or full-color printers that have multiple developing devices have difficulty reproducing faithful colors due to variations in toner density. Not only that, but during continuous printing, the output recorded images also have different color development.Human color vision is particularly sensitive, so it is necessary to keep each toner density precisely constant. need to be kept. In order to compensate for these drawbacks, there is a method of counting the number of dots forming an image area from the image signal, calculating the amount of toner consumption, and determining the amount of toner replenishment.
゛It is proposed.

With this method, the number of dots is more consumed in the image area than in the number of dots.
(To calculate the amount of toner consumed and determine the amount of replenishment.)
In addition to being able to accurately calculate toner consumption, fine control is also possible, which is advantageous for maintaining stable toner concentration.
.

It is.

However, toner consumption is not only proportional to the image area, but also depends on the developing device, toner storage area, and image carrier.
“It greatly depends on the environment around special holidays.

FIG. 9 shows the relationship between the surface potential of the image carrier (photoreceptor) and the output image density in the recording process of the same image information (same number of dots).

In this figure, H indicates a high humidity environment, N indicates a normal humidity environment, and L indicates a low humidity environment. In addition, the vertical axis shows the concentration,
The horizontal axis shows the surface potential.

As can be seen from this figure, even if the surface potential of each dot in the image area is the same, the toner density varies depending on the environment around the developing device, toner storage section, and image carrier. In other words, since the amount of toner consumed by the developing device has the characteristic of fluctuating depending on the environment, even if the amount of toner consumed that is uniquely determined from the number of dots is replenished, the toner density may be insufficient or excessive. There were many problems such as not being able to output an image with a desired density.

An object of the present invention has been made to solve the above-mentioned problems.The purpose of the present invention is to count the number of dots forming an image area based on the toner concentration in the developer and image information, and control the amount of toner replenishment. An object of the present invention is to provide an image recording device that can manage toner density with higher precision and stably maintain a set toner density over a long period of time.

[Means for Solving the Problems] The image recording device according to the present invention includes a replenishing means for replenishing developer to the developing means, detects the concentration of the developer filled in the developing means, and detects the concentration of the developer filled in the developing means, and detects the concentration of the developer filled in the developing means. Yes.

a first replenishment control means that controls replenishment of developer from the replenishment means; and a first replenishment control means that controls the replenishment of developer from the replenishment means, and a first replenishment control means that counts printed dots formed according to image information and replenishes the amount of developer from the replenishment stage according to the counting result. A second supply control hand that controls
' stage is provided.

[Effect]

In this invention, the second replenishment control means controls the amount of developer replenishment by counting the number of printed dots in the image area to be printed, and the first replenishment control means controls the developer replenishment amount by counting the number of printed dots in the image area to be printed. The second replenishment control means detects the concentration of the replenished developer and controls it so that the concentration of the replenished developer becomes a predetermined ratio. 1 Correcting the amount of developer remaining in the means. □ [Example] Fig. 1 is a sectional view of a replenishing means and a developing means showing an embodiment of the present invention, and 1 is a hopper serving as a replenishing means;
A developer, for example, yellow toner Ty (a mixture of magnetic powder made of iron powder or the like as a carrier and resin toner) is filled. 2 is a developing device serving as a developing means. 3
is a replenishment roll, and the replenishment roll 3 rotates in accordance with the drive of the pulse motor M to replenish the yellow toner TV to the lower part. 4.5 is a screw, developer D (yellow toner T
y) is circulated. Reference numeral 6 denotes a fixedly provided magnetic roller, which sucks up the developer by its magnetic force, moves in the direction of the arrow in accordance with the rotation of the sleeve 6a, and moves toward the housing 7.
In the more exposed portion A, development is performed on the photoreceptor 8, which serves as an image carrier.

Reference numeral 9 is a souffle bar that scrapes off the developer residue on the sleeve 6a. Reference numeral 10 denotes a developer concentration detection device (ATR), which is provided at a predetermined location of the developing device 2 and detects the developer concentration using optical means (described later).

Next, the operation will be explained.

The developer is transported from the front to the back of the drawing by driving the screw 4, and from the back to the front by driving the screw 5, and circulates within the developing device 2. During conveyance by the screw 4, the developer is sucked up by the magnetic force of the fixed magnetic roller 6, moves in the direction of the arrow as the sleeve 6a rotates, and supplies toner to the photoreceptor 8 at the part A exposed from the housing 7. and develop the latent image.

The amount of toner consumed in the developing process is replenished from the hopper 1 onto the screw 5 by the replenishment roll 3;
and stirred to homogenize. Supply roll 3 is
5. Driven by, for example, a pulse motor M, replenishes the desired amount of development on the image side. This drive control is performed by the
j', 1, is performed by the second replenishment control means.
・・・Figure 2 shows the developing device 2 and ATRl shown in Figure 1.
o This is a diagram explaining the relationship with □゛, and ATR
10 is a light source 10a, a light guide 10b, and an optical L/7 lens 10c.

Light guide 10d, light receiving element 10e, filter 0
The density of the developer is detected through the window 7a.
1゛The light from the light source 10a passes through the light guide 10b and the transparent window 7a.
It passes through and is irradiated onto the developer. From the developer,
Reflected light corresponding to the amount of toner is scattered, and a part of it enters the light receiving element 10e via the lens 10c, filter 10f, and light guide 10d. A developer concentration detection signal is obtained from this reflected light. Note that, as the filter 10f, for example, an external transmission filter is used, which is selected based on the spectral reflection characteristics of each toner.

FIG. 3 is a block diagram illustrating the control configuration of an image recording apparatus showing an embodiment of the present invention, 11 is a first replenishment control means of the present invention, and the output of ATRlo and the set value set in advance are shown. Comparator 1 that compares with the lower limit Sm1n
2. A comparator 13 that compares the output of ATRlo with a preset upper limit Sway. Comparator 12.13
Decoder 14. It is composed of a setting timer 15 and the like that determines the amount of rotation of the pulse motor M.

The second replenishment control means 21 of the present invention is a counter that measures the number of printed dots of the image forming section out of the image signal f transmitted from an external device (not shown).
'22, calculate the retoner consumption from the output of the counter 22.
Calculation circuit 23. It is comprised of a timer 24 that determines the amount of rotation of the pulse motor M based on the output of the calculation circuit 23, a reset circuit 25 that clears the contents of the counter 22, and the like.

3Q is an OR circuit, and the setting timer 5. Timer ′
Perform a logical sum with lid 4. 31 is the toner remaining amount calculation time
・On the road, 1st. The amount of developer remaining in the hopper 1 is constantly controlled according to the operation of the second replenishment control means it, 21.
□.

I'll update the time. 32 is a drive control unit, which has a setting tie;, M15. The replenishment drive section 33 is driven in accordance with the output of the timer 24.

Figure 4 shows comparators 12 and 13 and decoder 1 shown in Figure 3.
This is a diagram explaining the input/output relationship with 4.
a) to (c) show the operating states, and fHj and “
When fLJ occurs, input/output occurs, and input/output stops at fLJ.
There is.

Next, the operation will be explained.

The toner concentration detection signal outputted from ATRl 0 is compared with a preset lower limit Sm+n *upper limit S max of the set value by comparators 12 and 13, and the results are inputted to the decoder 14, respectively. Note that the upper limit Smax and the lower limit Sm1n are the upper and lower limits that are allowed in the process of toner concentration in the developer so that the output image density is good, not too much or too little, for example, for the developer (carrier + toner). The weight ratio of the toner in the toner is 13 ± 1% wt for yellow toner and magenta toner, 14 ± 1% wt for cyan toner, and 12 ± 1% wt for black toner, and each has a toner concentration of upper and lower limit values. The optimum image output can be obtained when

Decoder 14 receives input 1 from comparator 12 and outputs output 2 which sets timer 24 .

The output 2 of the timer 24 is determined according to the states (a) to (C) shown in FIG. The decoder 14 also includes a comparator 1
It receives input 2 from 3 and outputs an output 1 for setting the setting timer 15. The setting timer 15 is in the state shown in FIG.
Output 1 is determined according to a) to (C). For example, A
Output of TRl 0 ・When the value is smaller than the set value lower limit Sm1n, the output l becomes □゛rHJrHJ level becomes rLj level, only the setting timer 15 operates, passes through the OR circuit 3o, and the drive control unit 32 sets the setting timer. In response to the output of 15.

Then, the replenishment drive section 33 is driven for a predetermined period of time. This replenishment amount corresponds to 1% wt, and raises the toner concentration to the reference setting value.

Also, if the output value of ATRlo is within the setting range, output 1 is at rLJ level and output 2 is at rHJ level.
only becomes operational. The timer 24 uses a counter 22 to count the number of printed dots forming an image area based on the image signal fv, and a calculation circuit 23 calculates the consumption amount. Based on this result, the operating time of the timer 24 is determined. Ru. Furthermore, when the output value of ATRlo is larger than the upper limit of the set value S l1ax, as shown in states (a) to (C) shown in Fig. 4, both the output l and the specific output are at the rLJ level, and the replenishment operation is not performed. Not executed.

On the other hand, timer 15. At the same time that the output of the setting timer 24 is input to the drive control section 32 through the OR circuit 3o,
It is input to the remaining toner amount detection circuit 31. Further, when the consumption amount is calculated by the calculation circuit 23, the count value of the counter 22 is cleared by the reset circuit 25.

Next, the developer replenishing operation of the present invention will be explained with reference to FIG.

FIG. 5 is a flowchart illustrating developer replenishment control showing one embodiment of the present invention. In addition, (1) to (17)
indicates each step.

First, a counter value j counted by a counter (not shown) of the first replenishment control means 11 is initialized, that is, rOj
Set to (1). Next, it waits for a print key (not shown) to be pressed 2), and when the print key is pressed, ATRlo directly detects the toner density 3) and outputs a toner density detection signal to the comparators 12 and 13. In response to this, the comparator 12.13 changes the output of ATRlo to the preset upper and lower limit values Sm1n, 5Iiax
Compare with ru 5゜(4). In this comparison, ATR
When the IO output is smaller than the set value lower limit Sm1n,
A timer setting value for replenishing the predetermined amount t of toner is output to the setting timer 15, and the drive control section 32 drives the replenishment drive section 33 to replenish the toner by the predetermined amount t.
:・" (5). Next, the first supply control means 11
- Counter value j that counts the number of replenishments
6), and calculates the total replenishment amount A(jXt) by the first replenishment control means 11 (7). continue,
Compare the initial toner amount H in the hopper 1 with the total replenishment amount A. 8) If the initial toner amount H≦total replenishment amount A.

“.

For example, if it is determined that there is no toner, a warning will be displayed on the display section of the operation section (not shown) and the control will be terminated.8)
- If the amount H>total replenishment amount A, the second replenishment control means 21
In other words, in the comparison in step (4), the output of ATRlo falls within the upper and lower limits of the set value, and i
Read out the counter output Ni of the counter 22 that counts the number of printed dots to form an image from the image signal fv of the 1st sheet.
0), the calculation circuit 23 calculates the toner consumption amount Ti (α·Ni) (11).

Next, a timer setting value for replenishing toner corresponding to the calculated toner consumption amount Ti is set in the timer 24, and the drive control section 32 drives the replenishment drive section 33 to replenish the toner consumption amount Ti (12 ).

Next, calculate the total amount of toner B (ΣTi) that has been replenished (
L3). Next, the sum of the total replenishment amount A obtained by the first replenishment control means 11 obtained in step (7) and the total replenishment amount B obtained in step (13) is subtracted from the initial toner amount H, and the total replenishment amount A of the hopper 1 is Toner remaining amount K (H-(A+B)
) is calculated (14). Next, it is determined whether the remaining amount of toner K in the hopper 1 obtained in step (14) is >0 (15), and if NO, the process returns to step (9).
A warning is displayed and toner replenishment is waited for. If YES, the process returns to step (2) and waits for a print command generated by pressing the print key.

On the other hand, if it is determined in step (4) that the output of ATRIO is larger than the upper limit value Smax, the replenishment drive section 32 is maintained in a stopped state, the toner replenishment operation is stopped (for one day), and the printing process is stopped. 17) to continue, return to step (2), reduce the toner concentration in the developer, and
Supply drive unit 33 until the output value of 0 falls within the set value range.
When the output value of ATRlo falls within the set value range, step (
10) Move on to the following control. Note that the above operation is performed for each color of toner.

Next, a developing device and a replenishing device using one-component toner will be described with reference to FIG.

FIG. 6 is a sectional view of a developing device and a replenishing device showing another embodiment of the present invention, where 1, 3, 6° 6a, and 7.9 are the same as in FIG. 1, and Q is a level sensor. Then, the amount of toner filling in the bouncing 7 is detected as a position level.

The toner T moves with the rotation of the sleeve 6a, which has a roughened outer peripheral surface of the fixed magnet roller 6, and obtains tripo (triboelectric charge μc/g) by frictional charging with the surface of the sleeve 6a. A portion of the toner moving along the rotation of the sleeve 6d is regulated by the doctor blade 9, and the portion of the toner is coated with a predetermined thickness (ruorder) to develop a latent image. On the other hand, other toners reverse and move in the direction of arrow a, circulate within the housing 7, and repeat this process.
It obtains tripo again and contributes to development.

However, when the thickness of the toner in the housing 7 becomes extremely less than a certain level and new toner is replenished, the toner with insufficient tripping is also coated and developed, causing fogging or reverse development in one image. . Furthermore, when the level becomes extremely large, the toner's own weight above the housing 7 prevents it from moving in the direction of the arrow a, and the toner with insufficient tripping is developed.Therefore, it is necessary to control the toner within a predetermined level. There is a need.

Therefore, a level sensor Q is attached to a part of the housing 7, and the output of this level sensor Q is
By changing the output to 0, toner can be replenished with high accuracy as described above, and the remaining amount of toner T in the hopper 1 can be accurately managed. In addition, the level sensor Q
may be anything that detects a change in inductance or a change in natural frequency.

FIG. 7 is a flowchart of developer replenishment control showing another embodiment of the present invention. Note that (1) to (17) are the fifth
The flow is the same as that in the figure, and (21) and (22) indicate steps.

In step (4), the output value of ATRlo and the setting
゛Comparison of the upper and lower limits of the fixed value is performed, and the lower limit of the set value Sm1n
It was determined that ATRIO's output was smaller than
', it was done in a previous printing process.

Since it can be determined that the toner consumption amount, that is, the toner consumption amount calculated by the second replenishment control means 21 in step (11) is smaller than the actually consumed toner consumption amount, after step (8), A step (21) of increasing the conversion coefficient α by β (β>0) for calculating the toner consumption amount from the number of printed dots is provided, and the second replenishment control means 2
If the control operation is shifted to step 1, a calculation result closer to the actual consumption amount can be obtained using the corrected conversion coefficient α.

In addition, in step (4), the output value of ATRIO is compared with the upper and lower limits of the set value, and if it is determined that the output of ATR10 is larger than the lower limit of the set value S wax,
This is because it can be determined that the toner consumption amount performed in the previous printing process, that is, the toner consumption amount calculated by the second replenishment control means 21 in step (11) is greater than the actual toner consumption amount. , step (
After step 17), a step (22) is provided to reduce the conversion coefficient α by γ (γ>0), and if the control operation of the second replenishment control means 21 is performed, the corrected conversion coefficient α is used to Calculation results closer to actual consumption can be obtained.

As a result, for example, due to environmental changes, step (1)
Even if the calculation result in step 1) differs from the actual consumption amount and falls outside the set value range, the first control means returns it to the set value, and further correction process steps (21) and (22)
), the calculation result in step (11) can be brought as close as possible to the actual consumption amount, and the second replenishment control means 21, which can be finely adjusted over a long period of time, performs the replenishment operation, and as a result, the output image density can be maintained stably.

FIG. 8 is a sectional view of a color image recording apparatus to which the present invention is applied, where 8 is the same as in FIG. 1, ly,
in, 1c, 1bk are hoppers, and this j
Yellow toner TV and magenta toner Tm for replenishment at @
, cyan toner Tc.

It is filled with black toner Tbk. 6y.

Sleeves 6m, 6c, and 6bk develop each toner onto the photoreceptor 8. 31 is an optical system with multiple LEDs
' an LED array 31a and a light converging lens 31
b, and an LED driver (not shown) selects a desired LED array 3 according to the color-separated image signal.
1a selectively emits light to form a dot-shaped electrostatic latent image on the photoreceptor 8, which has been uniformly charged by the charger 32, through the light converging lens 31b. A cleaner 33 collects residual toner on the photosensitive body 81 after image formation.

Reference numeral 34 denotes a transfer drum, which is composed of a gripper 34a that grips the recording paper P, and a transfer charger 34b that transfers the toner image onto the recording paper P. 35 is a paper feed cassette which accommodates recording paper P. A peeling claw 36 separates the recording paper P onto which each toner has been transferred from the transfer drum 34. A conveyance belt 37 conveys the recording paper P to the fixing device 38. 39 is an output tray on which recording paper P is placed.

Note that the image forming operation is based on a known electrophotographic method, so a description thereof will be omitted.

In the above embodiment, a case has been described in which the image recording apparatus forms a latent image in the form of dots according to the image signal fv, but one image signal fv may be multivalued information including halftones.

In that case, a counter corresponding to multilevel information is provided to count the number of printed dots, and the blackening rate is determined from the sum of these dots.
It is sufficient to calculate the toner consumption amount. Further, the present invention can be easily applied even to a one-component development method using magnetic toner. Furthermore, it goes without saying that the exposure device for exposing the photoreceptor 8 may be a semiconductor laser, a gas laser, or the like.

〔Effect of the invention〕

As described above, the present invention includes a first replenishment control means that detects the concentration of the developer filled in the developing means and controls replenishment of the developer from the replenishment means according to the detection result, and image information. Since the second replenishment control means is provided, the second replenishment control means counts the number of printed dots formed according to the number of printed dots formed according to the count result, and controls the replenishment of developer from the replenishment means according to the counting result. "You can calculate the amount of developer consumed from the image information and determine the amount of replenishment.
In the two-component development method, the developer concentration during development can be finely adjusted, and in the one-component development method, the amount of developer in the developer container can be finely adjusted, and the image density between adjacent and consecutively printed output images can be adjusted. fluctuations can be minimized. Further, the fine adjustment by the second replenishment control means may cause the developer concentration to fluctuate due to the surrounding environment, etc.
- Even if the developer amount deviates from the set value range, it can be returned to the set value by the first replenishment control means. Furthermore, each time the first replenishment control means operates, the developer consumption calculation result of the second replenishment control means is corrected to bring it as close to the actual consumption as possible, so it is stable over a long period of time. The output image obtained is □゛′.

It has advantages such as:

[Brief explanation of drawings]

FIG. 1 is a sectional view of a replenishing means and a developing means showing one embodiment/example of the present invention, FIG. 2 is a diagram illustrating the relationship between the developing device shown in FIG. FIG. 4 is a block diagram explaining the control configuration of an image recording apparatus showing an embodiment of the present invention, FIG. 4 is a diagram explaining the input/output relationship between the comparator and the decoder shown in FIG. 3, and FIG. A flowchart illustrating developer replenishment control showing an embodiment of the present invention,
FIG. 6 is a sectional view of a developing device and a replenishment device showing another embodiment of the present invention, FIG. 7 is a flowchart of developer replenishment control showing another embodiment of the present invention, and FIG. 8 is an application of the present invention. FIG. 9 is a cross-sectional view of an image recording apparatus in which the image recording apparatus is used. FIG. 9 is a relative waveform diagram of surface potential and image density due to environmental changes. In the figure, 1 is a hopper, 2 is a developer, 3 is a supply roll, 4
．． 5 is a screw, 6 is a magnet roller, 7 is a housing, 8 is a photoreceptor, 9 is a souffle bar, 10 is a developer concentration detection device, 11 is a first replenishment control means, and 21 is a second replenishment control means. . Figure 1 Figure 2 Figure 4 Figure 6 Figure 5 Figure 7 Figure 8

Claims (2)

[Claims] (1) In an image recording apparatus that forms an electrostatic latent image in the form of dots on an image carrier according to image information, and visualizes the electrostatic latent image using a developing means, a developer is applied to the developing means. a first replenishment control means for detecting the concentration of the developer filled in the developing means and controlling replenishment of the developer from the replenishing means according to the detection result; Count the printed dots formed according to the information,
An image recording apparatus comprising: second replenishment control means for controlling developer replenishment from the replenishment means in accordance with the counting result. (2) The first replenishment control means detects the developer concentration and corrects the remaining amount of developer after the second replenishment control means replenishes the developer. 1)
The image recording device described in Section 1.