JPS62280869A - Picture controller - Google Patents

Abstract

PURPOSE:To sufficiently detect the toner sticking amount at a toner carrying body even in case of a toner for scarcely absorbing a light beam, by providing a control means for executing selectively a mode for controlling an image forming condition by detecting the variation of a regularly reflected light from the toner carrying body, and a mode for controlling the image forming condition by detecting the variation of an irregularly reflected light from the toner carrying body. CONSTITUTION:In case of using a black toner, a control part 16 allows a driving part 17 to execute the replenishment of a toner or the stop of its replenishment in accordance with whether VSP (the output of a photosensor 10 by a light beam reflected by the image of a reference pattern on a photosensitive drum 1)/VSG (the output of the photosensor 10 by a light beam reflected directly by the surface of the photosensitive drum 1) is larger or smaller than 0.125. When a color toner is used, the control part 16 controls the driving part 17 in the same way, based on 0.625 of the VSP/VSG value as a reference. Also, the control part 16 controls a driving device for rotating the photosensor 10, rotates the photosensor 10 to a position which becomes a regularly reflected light variation detecting state, in case of a black toner, and rotates the photosensor to a position which becomes an irregularly reflected light variation detecting state, in case of a color toner.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to an image forming apparatus such as a copying machine and a printer.

(Prior art) In image forming apparatuses such as copying machines and printers, the amount of toner adhering to the toner carrier is detected by detecting changes in reflected light from the toner carrier such as a photoreceptor, and the printing conditions are adjusted accordingly. I control is carried out at ℃. Generally, this detection of the amount of toner adhesion utilizes the characteristic that the reflected light from the toner carrier decreases as the amount of toner adhering to the toner carrier increases. However, when using a toner with low light absorption such as color toner, the reflected light from the toner carrier does not decrease even if the amount of toner adhering to the toner carrier increases.
The S/N ratio of the toner adhesion amount detection signal is insufficient, making control of image forming conditions unstable.

(Purpose) Does the present invention have the above drawbacks? An object of the present invention is to provide an image control device that can sufficiently detect toner adhesion on a toner carrier even when toner is removed and has low light absorption, and can stably control image forming conditions.

(Structure) The present invention is an image forming apparatus that detects changes in reflected light from a toner carrier to control image forming conditions. A mode in which image forming conditions are controlled using a detection port based on changes in specularly reflected light from the body, and a mode in which image forming conditions are controlled by detecting changes in diffusely reflected light from the toner carrier are selectively performed.

Next, examples of the present invention will be described.

FIG. 2 schematically shows an embodiment of a copying apparatus to which the invention is applied. In this embodiment, the photosensitive drum 1 is rotationally driven in the direction of the arrow by a driving section, and first uniformly charged with VC by a charging device and then exposed by a slit exposure device 2 to form an image. This slit exposure device 2 illuminates a reference pattern 4 having a predetermined reflectance provided at the bottom IK of a transparent document table 6 and a document on a document table 3 with a light source, and uses the reflected light to pass through optical systems 5 to 8. At the same time as the light source and the optical systems 5, 6 or the document platen 3 move, the reference pattern 4 and the light image of the document are projected onto the photoreceptor drum 1 in the order 1/(2) of the reference pattern 4 and the original. The reference pattern 4 is provided outside the document placement area of the document table 3,
For example, it is composed of a black pattern with a density of 1.80.

After the photosensitive drum 1 is exposed to light, the outside of the layer image forming area is neutralized by an eraser (not shown), and the 40 layer image of the basic pattern is copied 1[]n+1 (n is a positive integer) times from when the main switch is turned on. Cleared at times other than cycles. Further, the photosensitive drum 1 is removed by a developing unit 9 after being neutralized by an eraser.
- The a image is converted into an m image using color toner or black toner from the trap, and the aKCh toner adhesion condition of the developed image of the reference pattern 4 is detected by the photo sensor 10, and the developed image of the original is transferred to the transfer paper at the transfer unit. The remaining toner is cleaned and the static electricity is removed by the cleaning section and the static eliminating section in preparation for the next copy cycle.

A dry two-component developer consisting of (black toner or color toner) and a carrier is supplied to the photosensitive drum 1Vc by rollers 12 and 13 for monochrome development, and is transferred from the toner storage section 15 to the development container 11 by the replenishment roller 14. Toner of the same color is supplied to the developing device 9. This developing device 9 can be replaced with one that uses toner of a different color, and by this replacement, the color of the monochrome copy can be selected. 16 determines whether or not toner needs to be replenished based on the output signal of the photosensor sum, using different toner concentration control levels for black toner and color toner;
7 to rotate the replenishment roller 14, toner replenishment is performed. In this case, the control unit 16 & the image machine 9
It is determined whether the toner used is black toner or color toner from a signal given by the presence or absence of engagement between the harness and the pin in the harness of the main body of the copying apparatus. Further, the control unit 16 detects the end of toner and causes the display of the operation unit to display the end of toner. Figure 6 shows the specularly reflected light detection state of the photosensor 10. The photosensor/su 10 has a light emitting element 101 and detects purple.

A light emitting element 101 irradiates light onto the photoreceptor drum 1, and a detection element 102 detects a change in the specularly reflected light. Figure 4 shows the black toner, R, C) of the photosensor 10 (specular reflection light change detection state).

Characteristics of B (red, green, blue) color toners are shown f.

Although the photosensor 10 is sensitive to light with a wavelength of 950 nm, the photoreceptor drum 1 (selenium-based photoreceptor) does not absorb that light. Therefore, the output of the photosensor 10 is higher than that of the photosensitive drum 1, and this output (■3°)
For example, a, ovVC is set.

The R, G, and B toners have almost no absorption of light at 950 nm, and there is no difference in the output of the photosensor 10 depending on the color toner, and the output of the photosensor 10 is higher for color toner than for black toner. It is expensive and has poor sensitivity to color toner.

FIG. 5 shows a state in which the photosensor 10 detects a change in diffusely reflected light. In this state, the detection element 102 detects a change in the diffusely reflected light from the photoreceptor 1, and the characteristics of the photosensor 10 become as shown in FIG. Since the photoreceptor drum 1 is generally in the form of a base surface, the photosensor 10 is not activated when there is no IK toner layer on the photoreceptor drum or when black toner is attached to the photoreceptor drum 1.
There is almost no output. When color toner adheres to the photosensitive drum 1vc, the photo sensor 1
0 output increases. When using black toner, from the reference pattern 4Vc on the photoreceptor drum 1, the amount of toner adhesion on the formed portion is 0.35 mg/att.
When using the vc system, a proper image density can be obtained in copying. Therefore, the control unit 16 is configured as shown in Figure 3-7.
C”sp (output of the photosensor 10 due to light reflected by the image of the reference pattern 4 on the photosensitive drum 1)/V,
, (4.OVK installed in advance based on the output of the photosensor 10 due to the light directly reflected on the surface of the photoreceptor drum 10) is 0.
．． The drive unit 17 is caused to replenish toner or stop toner replenishment depending on whether it is larger or smaller than 5/4.0 = 0.125. In addition, when using color toner, the photosensitive drum 1
If the toner adhesion amount of the part where the a1 house is formed is controlled to 'r0.5m9/cn1 using the above reference pattern 4,
Copying will give you the right painter. Therefore, the control unit 16 calculates v8P/"so as 2.5/4.0 = 0.62
Depending on whether it is larger or smaller than 5, the drive unit 17 Vc should stop toner replenishment or perform toner replenishment. However, the difference from the case of black toner is that toner replenishment stops at VsP/■8o>0.625 (tof-replenishment < ), "ap/
Toner replenishment is performed when V8o<0.625. Further, the control unit 16 controls the drive device that rotates the photosensor 10 to rotate the photosensor 10 to a position where a change in specular reflection is detected in the case of black toner, and a change in diffused reflection light in the case of color toner. Rotate it to the position where only one head is detected.

In addition, as shown in Figure 8, the light emitting element 1
01 and two detection elements 102 and 103, the detection elements 102. 103 may be detected respectively. In this case, the output of the detection probe 102 (V8.)
4. Set it to Ov.

FIG. 10 shows in detail the density check routine of the control section 16 in the case of black toner. In this density change control routine, the control unit 16 first uses a photo sensor (hereinafter referred to as P).
2p sensor check whether it is the timing to check the output signal of 10 (referred to as sensor) REQ FLAG
(Request flag) Check and decide. This P sensor check REQ FLA() is V every 10 copies.
The image formed by the reference density pattern 4 formed once C is set at the timing when the image thereafter passes the detection position of the P sensor 10, and in this evening/f mink, the image formed by the reference density pattern 4 is formed by the P sensor 10. Detected or not?
The determination is made based on the output signal of the P sensor 10. If the image is detected normally, the output signal of the P sensor 10 is sampled and converted into data of 1 byte at a time and stored in the memory.

Here, base 4 density pattern 4 is the standard density, and the output signal of the P sensor button is the standard density butter/4 as shown in Figure 9.
The potential VsP of the part corresponding to VC is about 0.5V, and the potential V□ of the background part before and after it is 4Vvc. Also 2.5■
P sensor switching point, 1.5 V? : Treated as an abnormal value of P sensor. Next, from the data stored in the memory above, P
Determine the data position of ■ by the C/S switching point and
The average value of the byte data is taken and entered into (1)83 average value buffer and (2)8 display buffer. And this ■8. It is determined whether the average value is smaller than the P sensor switching point, and if it is not smaller, it is considered normal and the process proceeds to the averaging process at ℃■8P.

In this process, P sensor check REQ FLAG?
IJ upper set v8P of the first 8 bytes from the above memory
Take out the data and find the average value. This average value is put into the P average 1 direct buffer and the VsP display buffer, and it is determined whether the P sensor is abnormal or not. If not, t'th is considered normal and toner replenishment judgment processing is performed.In this processing, it is determined whether the Vsg average value is greater than 8 x V, P average value, and if it is not, toner replenishment R is performed.
Set EQ FLAG. Next, supply stop IF
LAG, supply suspension 2FLAG, supply department QIFLAfl
.

Supply REQ2FLA(), supply section Q3FLAG
Reset.

If the 78g average value is larger than the P sensor switching point, P sensor abnormality FLA() is set and P sensor check REQ FLAG is reset.

If the P sensor 10 cannot detect the detection based on the standard density pattern, set 0FFH in the 33 display buffer, and set toner replenishment REQ3FLAG and toner oil supply QFL.
Set AG, P sensor variant FLAG, and
Sensor check REQ FLAG '& reset.

When the toner replenishing section Q FLAG is set, the drive section 17 is turned on for a certain period of time every time one copy is made to perform toner replenishment. When toner replenishment REQ3FLA() is set, the time during which the drive unit 17 is turned on is lengthened to increase the toner replenishment amount f;r:. If the toner cannot be detected by the visualization &P sensor based on the Yasushi quality pattern even after this, replenishment stop 2 F'LA() is sent, the drive unit 17 is stopped, and toner replenishment is stopped.

When the v8P average value becomes larger than the P sensor abnormal value, set the replenishment REQ I FLAG, transfer the contents of the ■82 average value buffer to the previous ■BP average value buffer, and set the toner replenishment REQ FLAG, P sensor P sensor check REQ 1 with abnormal FLAC)
Reset rLA(). Supply REQI FLAG
In the case where the drive unit 17 is turned on, the time for turning on the drive unit 17 is one step longer than usual.

As a result, ■3. If the average value is smaller next time than last time, replenish REQ1FLAG'! II'! J is set, but if it is dropped in step 5, replenishment REQ2FLAG is set to move the contents of the v8P average value buffer to the previous V8P average value buffer.

The time to turn on the drive unit 17 is determined by the replenishment REQ2 FLA (
), the toner replenishment amount is further increased by one step of Vc. As a result, ■ If the average value of 8F is smaller next time than the previous time, replenishment REQ1FLAG, replenishment part Q2F
LAG is reset, but if this does not occur, replenishment stop I FLAG is set, the drive unit is stopped, and toner replenishment is stopped.

The toner replenishment determination processing portion 107 in Fig. A.10 may be changed to either the example shown in Fig. 11 or 12. In the example of Figure 11, if the average value becomes larger than the 8×VaP average value, the toner replenishment REQ FLAG is set. If the toner end check FLAG is not set, set this and v8P average value ¥
Put it in the previous V8F average value buffer, and the next vBP average value will be the previous time ■8. If the value is not smaller than the average value buffer value, the toner end display section displays that the toner in the toner storage section 15 has run out. The next V8p average value is the previous V
If the IIP average value is too small, the toner end check FLA() is reset, and if the v8P average value is 8XV, which is thicker than the P average value, the toner end check FLA() is reset.

In the example of Figure 12, if the value is greater than the ■s6 average value or 8×■8P average value, set 8 REQ FLAO in the toner supplement, and when the VBP average value reaches the predetermined toner end level, the toner end display will be displayed. make it work.

The performance check routine of the control unit 16 in the case of color toner is almost the same, but as shown in the off-line diagram, the determination as to whether or not toner can be replenished is different from that in the case of black toner.

The above embodiment deals with monochrome copying, but when full-color copying is performed, for example, cyan is used.

The present invention can be similarly implemented when copying is performed using a mixture of six color toners, magenta and yellow, and black toner.

Further, the present invention can be similarly implemented in an image forming apparatus such as a printer, and other image forming conditions may be controlled instead of controlling toner supply.

(Effects) As described above, according to the present invention, there is a mode in which the IIF: image condition is controlled by detecting changes in the specularly reflected light from the toner carrier, and a mode in which changes in the diffusely reflected light from the toner carrier are detected. Since it has a mode for controlling the image forming conditions, it is possible to sufficiently detect the amount of toner adhering to the toner carrier, whether it is black toner or toner with low light absorption such as color toner, and to stably control the image forming conditions. Can be done.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the construction of the present invention, Figure 2 is a schematic diagram showing an embodiment of a copying device to which the present invention is applied, 3-6
The figure is a diagram showing the specular reflection light change detection state of the photosensor in the same example, the 4th figure is a characteristic curve diagram showing the output characteristics of the same photosensor in the specular reflection light change detection state, and the 5th figure is a characteristic curve diagram of the same photosensor. Figure J-6 is a characteristic curve diagram showing the output characteristics of the diffused reflected light change detection state of the photocell, and the OFF diagram is a flowchart showing the processing flow of the control section in the above embodiment. , Figure 8 is a diagram showing an example of the 7-point sensor, Figures 3-9 are diagrams for explaining the above embodiment, Figure 10 is a flowchart showing the concentration check routine of the control section, Figures 11 and 12. is a flowchart showing a partially modified example of the same degree check routine. 100...ftl control means. (Figure 2 3m 4th item Toner adhesion amount (mS/c) 5 Figure 6 Toner adhesion amount t (m9/cm') Figure '1 8th side 9th haze

Claims (1)

[Claims] In an image control device that controls image forming conditions by detecting changes in light reflected from a toner carrier in an image forming apparatus, there is a mode in which the image forming conditions are controlled by detecting changes in specularly reflected light from the toner carrier. 1. An image control device comprising: a control means for selectively controlling image formation conditions by detecting changes in diffusely reflected light from a toner carrier.