JPS6327868A - Toner supply controller for copying machine - Google Patents

Abstract

PURPOSE:To prevent trouble from occurring even when a toner color is changed by forming a toner image corresponding to a reference density pattern on a photosensitive body and controlling toner supply according to the ratio of its light reflectance and the light reflectance of the surface of a photosensitive body. CONSTITUTION:Toner supply is controlled according to the ratio of the light reflection factor of the photosensitive body surface and the light reflectance of the toner image of the reference density pattern. Namely, 8 early data among 16 sampling data are utilized to compute their mean value, which is stored in a Vsg mean value register Mvsg and in a specific display register and also displayed on a display device. Then, the contents of the register Mvsg are compared with a fixed value (Vch). The mean level corresponding to the light reflectance of the photosensitive body surface is normally stored in the register Mvsg, so Mvsg>Vch and the toner supply is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention controls the concentration of developer used in the formation of visible images in electrostatic copying machines. The present invention relates to a toner replenishment control device for a copying machine.

[Prior Art] In an electrostatic recording device, on a charge carrier,
An electrostatic latent image corresponding to the image to be recorded is formed, and toner is attracted to this electrostatic latent image, thereby forming a visible image.

A developing unit that visualizes the electrostatic latent image contains a developer. Generally, a developer is composed of two components: resin-coated iron powder and powdered toner. Then, due to the friction between the iron powder and the powder toner, the powder toner is charged to a polarity opposite to that of the photoreceptor, and is attracted to the electrostatic latent image. Therefore, since only powder toner is attracted to the electrostatic latent image, when a developing operation is performed, the ratio of iron powder to powder toner, that is, the developer concentration changes. Therefore, when the developer concentration decreases, powder toner is replenished from the toner replenishment tank to control the developer concentration to be constant.

Various control systems have been proposed in the past as this type of control system, but the one described below is probably the most preferable.

A reference density pattern is provided at the edge of the original reading surface, this pattern is read together with the original by a scanner, an electrostatic latent image corresponding to the read image is formed on the photoreceptor, and this electrostatic latent image is developed to create a printable image. Form a visual image. Then, the optical reflectance, that is, the density, of the visible image of the reference density pattern formed on the photoreceptor is read by a reflective optical sensor. The density of the toner image of the standard density pattern formed on the photoconductor reflects the results of the processes of the image reading system, charging system, and development system, so it depends on the light intensity of the exposure lamp, the voltage of the main charger, the developing bias voltage, and the toner image. Various process elements such as concentration are adjusted to control the readings of the optical sensor so that they approach a predetermined state. In other words, if the density of the toner image of the reference density pattern formed on the photoreceptor is low, it is considered that the density of the developer has decreased, so in this method, toner is replenished. There is no need for a sensor or the like to directly detect the concentration of the developer, which simplifies the configuration. Moreover.

Since the states of all process elements such as the original reading system, charging system, and developing system are fed back to the control, copying characteristics, that is, the relationship between original density and copy density can be maintained constant.

By the way, recent copying machines are configured so that they can record in any color of their choice. In other words, since the developing unit is cartridge-type and can be attached to and removed from the copying machine body, it is possible to prepare multiple developer cartridges, each filled with a different color toner, and selectively install the developer cartridges into the copying machine. This allows you to copy using your favorite color toner.

However, as a matter of course, different toner colors have different light reflectances, so as mentioned above, the developer density (
When detecting the ratio of toner to iron powder, replacing the developer cartridge causes a detection error. Specifically, color toner has a higher light reflectance than black toner, so if you control it so that there is no error when using black toner, it will result in oversupply of toner and adverse effects such as toner scattering. arise.

[Objective of the Invention] The present invention forms a toner image of the above-mentioned standard density pattern on a photoconductor and detects its light reflectance to control the density of the developer, and also eliminates the problem of changing the toner color. The purpose is to provide a control device that does not cause

[Structure of the Invention] In order to achieve the above object, in the present invention, toner is replenished according to the ratio of the light reflectance of the surface of the photoreceptor to the light reflectance of the toner image of the reference density pattern formed on the photoreceptor. At the same time, a color detection means is provided which outputs an electric signal corresponding to the selected toner color, and the relationship between the ratio and the toner supply amount is automatically adjusted according to the electric signal outputted by the color detection means. do.

As a result, the concentration of the developer in the developing unit can be maintained in a desirable state regardless of which color toner is used.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[Example] The present invention will be described in detail below with reference to one drawing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made to FIG. 1, which shows one type of copying machine embodying the present invention. Briefly speaking, this copying machine consists of a copying machine body, an ADF (automatic document feeder) 60. Sorter 70. Automatic double-sided processing unit 80. It consists of a group of optional units such as a paper feed unit. The paper feed system that supplies recording sheets has five stages. That is, the first paper feeding system and the second paper feeding system are provided in the main body of the copying machine, and the third paper feeding system is a second paper feeding unit and a third paper feeding system including a fourth paper feeding system and a fifth paper feeding system. The paper feed unit is connected to the copier main body. 21, 22, 23 and 24 are the first paper feeding system, respectively;
These are cassettes provided in the second paper feeding system, the third paper feeding system, and the fourth paper feeding system, and 25 is a tray of the fifth paper feeding system.

A contact glass l on which a document is placed is provided at the top of the main body of the copying machine, and an optical scanning system 30 is provided below it. The optical scanning system 30 includes an exposure lamp 31. 1st
Mirror 32. Second mirror 33° Third mirror 34. Lens 35. A fourth mirror is provided with a 36° slit 37, etc. When performing document reading scanning, the first
The carriage and the second carriage carrying the second mirror 33 and the third mirror 34 are mechanically driven for scanning at a relative speed of 2:1.

This scanning direction, that is, the sub-scanning direction is the left-right direction in FIG. 1, and the sub-scanning start position of the scanning system is at the left end.

A reference density pattern PP is arranged at an image reading position near the sub-scanning start position of the scanning system, specifically, at a position adjacent to the left of the left end of the lower surface of the contact glass l. This reference density pattern PP is a sheet formed with a black pattern having a predetermined light reflectance, and is approximately 20 mm in the sub-scanning direction.
It has a length of

The lens 35 is a zoom lens, and its magnification can be changed by driving a motor.

Therefore, the light emitted from the exposure lamp 31 is reflected by the image reading surface (reference density pattern pp or the original), and is reflected by the first mirror 32.
．． Second mirror 33. Third mirror 34° lens 35. Fourth
Through the mirror 36 and the slit 37, the photosensitive drum 2
imaged on top.

Around the photoreceptor drum 2, there are a main charger 3 and an eraser 4. Developing cartridge 5. Toner image sensor PSEN
, a transfer charger 7, a separation charger 8, a tickling unit 9, etc. are arranged.

The image reproduction process will be briefly explained. The surface of the photosensitive drum 2 is uniformly charged to a predetermined high potential by the discharge of the main charger 3. The charge in the portion not used for image reproduction is erased by the eraser 4. When the charged surface of the photoreceptor drum 2 is irradiated with reflected light from the original, the potential of that part changes (decreases) depending on the intensity of the irradiated light.
do. The photosensitive drum 2 rotates in the direction shown by the arrow in the figure.
In synchronization with this, the optical scanning system 30 sequentially scans the document surface, so that a potential distribution corresponding to the density (light reflectance) distribution of the document image, that is, an electrostatic latent image, is formed on the surface of the photoreceptor drum 2. Ru.

When the portion on which the electrostatic latent image is formed passes near the developer cartridge 5, the toner in the developer cartridge 5 is attracted to the surface of the photoreceptor 2 according to the potential distribution, thereby developing the electrostatic latent image. A visible image corresponding to the electrostatic latent image is formed on the photoreceptor drum 2.
formed on top. On the other hand, in synchronization with the progress of the copying process, recording sheets are supplied from one of the five paper feeding systems selected. This recording sheet is fed through the registration rollers 27 at a predetermined timing so as to overlap the surface of the photosensitive drum 2.

The transfer charger 7 transfers the visible image (toner image) on the photoreceptor drum 2 onto the recording sheet, and the separation charger 8 separates the recording sheet to which the visible image has been transferred from the photoreceptor drum 2. The recording sheet separated by 0 is conveyed to a fixing device 12 by a conveyor belt 11. After passing through the fixing device 12, the toner image on the recording sheet is fixed onto the recording sheet by heat within the fixing device 12. The recording sheet that has been fixed is discharged to the sorter 70 or the automatic duplex unit 80 through a predetermined paper discharge path.

In this example, the length of the photosensitive drum 2 in the axial direction (direction perpendicular to the paper surface), that is, the maximum recording width, is approximately the same as the short side length of A3 size.
When recording an image smaller than the B4 size, the remaining area other than the B4 size image forming area is wasted. The remaining area remains at a high potential even after exposure, so if that area is developed as it is, a large amount of toner will adhere there. In that case, a large amount of toner is wasted and the burden of cleaning increases.

Therefore, the charge in the area other than the image forming area is usually removed by the eraser 4 located upstream of the developer cartridge 5.
It is erased as shown in the figure. The eraser 4 is a rod-shaped device in which a large number of light emitting elements are arranged in a line along the entire length of the photoreceptor drum 2.
For example, if the size of the image forming area is B4 size, when the eraser 4 faces the image forming area, all the light emitting elements in the 84 size area of the eraser 4 are turned off. , all the light emitting elements outside it are turned on. When exposed to light from the light emitting element, the charge is erased.

The reference density pattern PP has a length corresponding to the ASR size in the axial direction of the photoreceptor drum 2, and is arranged at the center of the photoreceptor drum 2 in the axial direction. As shown in FIG. 8, the electrostatic latent image formed on the photoreceptor drum 2 during the reading scan of the reference density pattern PP is located in the reference pattern forming area slightly in front of the image forming area. When forming a toner image of a reference density pattern on the photoreceptor drum 2, when the reference pattern forming area faces the eraser 4,
All the light emitting elements within the area corresponding to the ASR size of the eraser are turned off, and erasing of the reference density pattern is prohibited.

FIG. 2a shows a specific configuration of the developer cartridge 5.

Figure 2b, Figure 2C, Figure 2d, Figure 2e, Figure 2f,
This is shown in Figures 2g and 2h. The developer cartridge 5 will be explained with reference to each episode.

FIG. 2a is a perspective view of the entire developing cartridge 5. FIG. Referring to FIG. 2a, a U-shaped handle 112 is provided on the case end plate 111 of the developer cartridge 5. As shown in FIG. The developer cartridge 5 can be attached to and removed from the main body of the copying machine by being inserted and removed from the front side in FIG. 1 in the axial direction of the photosensitive drum 2. The developer cartridge 5 is carefully supported by the handle 112 during attachment and detachment. On the copying machine main body side, there is a guide rail 1 arranged along the axial direction of the photoreceptor drum 2.
13 are provided. By sliding the developer cartridge while engaging the guide rail 113 with a downward guide groove 115 formed integrally with the upper case 114 of the developer cartridge, the direction of movement of the developer cartridge when installing and removing it is correct. be regulated. The positioning of the developer cartridge with respect to the photoconductor drum 2 is performed by inserting the developer cartridge 5 into the copying machine main body, inserting the positioning hole 116 provided in the case of the developer cartridge into the positioning fixing pin 117 on the copying machine main body side, or by inserting the positioning hole 116 provided in the case of the developer cartridge into the positioning fixing pin 117 on the copying machine main body side. This is mainly done by fitting the rear end 118 of the support shaft of the developing sleeve into the positioning six 119 on the copying machine main body side. The positioned developer cartridge has one handle 112.
It is held in its installed position by engaging a hook 112a provided at the base of the copying machine with a retaining protrusion on the main body of the copying machine.

2b is an enlarged view of the developing cartridge 5 shown in FIG. 1.6 Referring to FIG. 2b, a non-magnetic developing sleeve 121 containing a fixed magnet group 120 is attached to both end plates of the developing cartridge case. Developer stirring impeller 122. A developer conveying screw 123 formed of a spiral thread and a toner replenishing rod 124 having a plurality of parallel vertical grooves 124a on the circumferential surface are each rotatably supported.

A cylindrical case 125 formed on the shoulder of the developer cartridge 5 houses a toner cartridge 126 having a cylindrical body. At both end plates of the toner cartridge 126, a toner replenishment par 127 is provided in the center thereof, the both ends of which are rotatably supported. Toner supply bar 127
The rear shaft end of the toner cartridge protrudes from the end plate of the toner cartridge, and an engaged member 128 having a sawtooth piece 128a is fixed to the protruding end, as shown in FIG. 2c.

When the toner cartridge 126 is inserted and attached to the developer cartridge 5, the engaged member 128 engages with the engaging member 129 on the developer cartridge side and becomes integrated in the rotational direction.

The engaging body 129 is fixed to the inner end of a shaft 131 of a gear 130 that is mounted on the outer surface of the case of the developer cartridge.

The gear 130 is connected via an intermediate gear 132 to a gear 133 fixed to the shaft end of the toner supply rod 124 .

Gears 134 and 135 are fixed to both shaft ends of the developer stirring impeller 122, and one gear 134 has a gear 136 fixed to one end of the toner conveying screw.
And to the other gear 135.

Gears 138 fixed to the shaft end of the developing sleeve 121 via an intermediate gear 137 are in mesh with each other. The gear 134 is provided with a knob 139 for manually rotating the developer stirring impeller 122. Each of the gears described above is arranged on the outer surface of the case end plate of the developer cartridge.

When the developer cartridge is installed in the copying machine main body, the gear 13
3 and 138 are drive gears G1 and G2 on the copying machine main body side.
The gears 30, 32 to 38 are each driven to rotate in the direction of the arrow in the figure.

In FIG. 2b, the height of the magnetic brush on the developing sleeve 121 is regulated to a predetermined height by a blade 140 fixed to the developing cartridge case 114. The excess developer scraped off by this blade 140 moves the developer conveying plate 141 to the right in the figure, and as shown in FIG.
41a and falls onto the developer stirring impeller 122.

The developer at one end of the conveying plate 141 is transferred from the hole 143 formed in the Wi conveying plate 141 to the conveying screw 12.
The developer that falls onto one end of the tray 1 is conveyed toward the other end by the conveying screw 123, and the receiver is placed on the tray 1.
The developer is returned to one end of the developer stirring impeller 122 through a delivery port 145 provided at the end of the developer. The developer transport unit 146, which is composed of a transport plate 141 housing the toner transport screw 123 and a tray 144, is placed above the developing sleeve 121 and the developer stirring impeller 122 by having both ends thereof fixed to the developer cartridge case. Supported.

In FIG. 2b, the toner supply rod 124 is connected to the hopper 15.
It is arranged so as to close the lower opening 151 of 0. The inner surfaces of both sides of the lower opening 151 of the hopper 150 are provided with replenishment ll1.
Elongated elastic members 152 and 15 that contact the peripheral surface of 124
3 is provided. These elastic members 152, 153
is made of synthetic resin material. A feeler 154 is swingably provided at the top of the hopper 150. The tweeter 154 is cantilevered from one end plate of the hopper 150, as shown in FIG. 2d.

A boss 156 of an arm 156a is fixed to the outer end of the shaft 155.

The tweeter 154 is given a rocking habit by the relatively weak elasticity of the spring 158, and the arm 156a is L//<
-159 is lightly pressed against one end 159a from below. A pin 160 is fixed to the other end 159b of the lever 159, and the pin 160 is attached to the cam 13 integrated with the gear 130.
0a by the force of the spring 61 acting on the lever 159.

L//<-159 is supported by a stud 162 on the outer surface of the end plate of the developer cartridge case.

In FIG. 2f, a toner supply port 165 is provided in a part of the cylindrical peripheral wall of the toner cartridge 126, and both end plates 166 and 16 of the toner cartridge 126 are provided with a toner supply port 165.
7 have radial protrusions 166a and 16, respectively.
6c, 167 is provided. A grip tube 166b is integrally formed on one end plate 166, and a lid tube 168 is screwed into it.

Insert the toner cartridge 126 into the case 125 with the protrusion 167a aligned with the groove 125a (FIG. 2a) formed on the inner peripheral wall of the cartridge case 125, and with the protrusion 166a completely inserted into the groove 125a, Cartridge 126.

When rotated counterclockwise in FIG. 2b, the replenishment port 165 of the cartridge 125, which will be described later, communicates with the upper opening of the hopper 150 and the opening 170a of the shutter plate 170. In this case, the protrusion 166a engaged with the groove 125a
and 167a are grooves 125a provided in the case 125.
It can rotate along a circumferential groove connected to the

The shirt shirt plate 170 is made of a plastic molded body having reinforcing ribs on its inner surface, and as shown in Fig. 2h, protrusions 71 to 74 protruding in the longitudinal direction are integrally provided at both end corners thereof. . These protrusions 71 to 74 are provided on the inner surface of both ends of the case 125, and are provided in arcuate grooves (not shown).
It is loosely fitted into the opening 170a of the shirt shirt plate 170.
supports the shutter plate 170 so as to be rotatable along the inner wall surface of the case 121 within a range of positions where the upper opening of the hopper is closed and opened.

When the toner cartridge 126 is inserted into the case 125, one protrusion 167a of the cartridge 126 faces the opening of the notch 170b of the shirt shirt plate 170 inside the case, while the protrusion 166c of the end plate 166 of the cartridge
is the right side of the protrusion 172 of the shirt cover plate 170 I3172 a
to face. In this state, when the grip cylinder 166b of the toner cartridge 126 is grasped and rotated counterclockwise in FIG.
70b, and first the supply port 165 of the toner cartridge 126 and the opening 1 of the shutter plate 170.
70a, and when the cartridge 126 is further rotated, the opening 1170a of the shirt shirt plate 170 will coincide with the upper opening of the hopper 150 in its final position.

When removing the toner cartridge 126 from the case 125, the toner cartridge 126 is rotated clockwise from the state shown in FIG. 2b.

The protrusion 166c of the cartridge 12G is connected to the shirt plate 170.
The side edge 172a of the protrusion 172 is pushed around, the shirt flap plate 170 is rotated in the same direction, and the upper opening of the hopper 150 is closed. Cartridge 126 is.

The protrusions 166a and L67a are the grooves 125 of the case 125.
It rotates to a position that coincides with a, and is pulled out in the axial direction at that position. Therefore, when the toner cartridge 126 is removed from the case 125.

The shutter plate 170 closes the opening of the hopper 150.

Referring again to FIG. 2a, a light shielding plate 41 is disposed above the developer cartridge 5. As shown in FIG. This light shielding plate 41 is
The developer cartridge 5 is placed in the optical path of the toner color sensor C3EN in a state where it is correctly installed at a predetermined position in the main body of the copying machine. The toner color sensor C3EN includes three sets of transmission type optical sensors composed of one light emitting diode and a phototransistor, and is fixed to a guide rail 113 on the copying machine main body side. Four developing cartridges 5 are prepared, each loaded with black toner, blue toner, green toner, and sepia toner. Different light shielding plates are installed. Therefore, the state of the 3-bit electrical signal output from the toner color sensor C3EN changes depending on the toner color in the installed developing cartridge.

FIG. 3 shows an operation board arranged on the top surface of the main body of the copying machine shown in FIG. Referring to FIG. 3, this operation board includes a number of key switches Kl.

K 2 * K 3 HK 4 a HK 4 b H
K 5 g K 6 a gK6b, 7. 8. 9
a, 9b, 9c.

KIO, Kll, 12a, 12b, 13°KC,
KS, to #, Kl and KT and a number of indicators DI, D2
．． D3. D4. D5. Ds+ Dg+Dd, Dp, Dt
, De1, etc.

The various typical key switches provided on the operation board will be briefly explained.

Kl is a key for specifying the operation mode of the sorter 70, and by operating this key, one of the fixed (two-seed use) mode, sort mode, and stack mode can be specified.

K3 is a key for specifying the operation mode of the automatic document feeder 60, and by this operation, one of manual document setting mode, ADF mode, and 5ADF mode can be specified.

K4a and K4b are keys for specifying the front and back margin positions, respectively. K4a, K6b, K9a, K9b and K9c are used to specify the copy magnification.

K7 is used to specify double-sided copy mode.

K8 and Kll are used to specify the document size and paper feed system selection, respectively.

KIO is a numeric keypad and is used for specifying the number of copies, etc.

K12a and K12b are used to specify copy density.

KC is the clear/stop key, and 10 is on the numeric keypad.
This is used to clear the number of copies specified and to instruct the stop of the copy operation.

KS is a key for instructing to start printing.

A brief explanation of typical indicators provided on the operation board will be given below.

Dl is a 7-segment, 2-digit numerical display.

In the normal operation mode, the set value for the number of copies is displayed during standby, and the number of copies is displayed during copying.

Dl displays the copy density setting state.

Ds displays the paper size, paper orientation, and selected paper feed system for each paper feed system.

D4 is a 7-segment, 3-digit numerical display that displays the copy magnification in units of 1% in the normal operation mode.

Ds displays the specified document size.

Ds is an indicator that displays an abnormality in the sorter, Dg is an indicator that displays an abnormality in paper feeding, Dd is an indicator that displays the cover open state, and DP is an indicator that displays no recording paper.

Dt is an indicator that lights up when toner runs out. However, if an abnormality in the surface density of the photosensitive drum is detected in the toner detection process described later, the 1 indicator Dt blinks.

Del displays the color of the toner loaded in the developer cartridge 5. That is, the toner color is black or blue.

Symbol K for green and sepia, respectively.

B, G and S are displayed brightly.

FIG. 4 shows an outline of the electric circuit configuration of the copying machine shown in FIG. 1. Referring to FIG. 4, the main control board 200 includes a microprocessor 210. Read-only memory (ROM
)220. Read/write memory (RAM) 230. Parallel ■/○ port 240° Serial I10 port 250. A
A /D (analog/digital) converter 260 and a timer 270 are provided. This main control board 200 includes an operation board 310 (see FIG. 3), an optical system control board 320. Lamp control board 330. Heater control board 340. High voltage power supply unit 350. Automatic document feeder!
! 60. Sorter 702 Double-sided processing device 80° Paper feeding unit 360. Drivers 370, 380 and signal processing circuit 39
0 is connected.

The optical system control board 320 controls the electric motor M1 for scanning drive of the optical scanning system 30 and the electric motor M2 for adjusting the magnification of the zoom lens by K14.

The lamp control board 330 controls the light amount of the exposure lamp 31 of the optical scanning system 30.

The heater control board 340 controls the temperatures of the fixing heater HTI provided in the fixing camera 12 and the drum heater HT2 built in the photosensitive drum 2.

The high voltage power supply unit 350 includes the main charger 3, the bias electrode 5a of the developer cartridge 5, and the transfer charger 7.
and generates high voltage power to be applied to each of the separate chargers 8.

Various AC loads (400) are connected to the driver 370, and various DC loads (400) are connected to the driver 380.
10) is connected to the signal processing circuit 390, and various sensors (420) are connected to the signal processing circuit 390.

Specifically, typical AC loads 400 include a main motor for driving the photoreceptor drum 2 and the like, a developer cartridge motor, a conveyance fan motor, and a cooling fan motor. Typical DC loads 410 include a cleaning control solenoid, a registration roller control clutch, a separation claw control solenoid, an eraser 4. These are a total counter, a toner replenishment control solenoid, and an oil replenishment control solenoid.

Furthermore, typical of the various sensors 420 is a timing pulse generator that generates pulses synchronized with the rotation of the main motor, and a toner image sensor PSEN.

These are a toner color sensor C3EN, a registration sensor that detects recording paper near the registration roller 27, a paper size sensor and a paper presence/absence sensor provided in each paper feeding system.

Regarding the toner image sensor PSEN, reference is made to FIG. 7a, in which a specific circuit is shown in FIG. 7a. Toner image sensor PS
EN consists of one light-emitting diode and a phototransistor, and the anode of the light-emitting diode is connected to the power supply line (
+5V), and its cathode is connected to the output port P out of the main control board 200 via a resistor R2 and a variable resistor VR. Therefore, the boat p ou
By controlling t, the light emitting diode of sensor PSEN can be turned on/off. The output terminal, ie, the emitter, of the phototransistor is connected to the input terminal of the A/D converter 260 in the main control board 200 via the analog input port Pin of the main control board 200.

FIG. 7b shows the relationship between the density of the toner image formed on the photosensitive drum 2 and the output voltage of the sensor PSEN that detects the image density. Referring to FIG. 7b, it can be seen that as the image density increases, the output level of the sensor PSEH decreases.

Furthermore, it can be seen that the correlation between the image density and the PSEN output level changes depending on the color of the toner used.

FIG. 5 shows a part of the memory map of the main control board 200, and FIG. 6a shows an outline of the processing contents of the main control board.
Figures 6b, 6c, and 6d.

6e, 6f, and 6g show in detail some of the processes included in the process of FIG. 6a.

First, reference is made to FIG. 6a. When the power is turned on.

First, CPU initialization processing in step SAI is performed. In this processing, the state of the main control board 200 itself is initialized. That is, the contents of the read/write memory 230 are cleared, various mode settings are initialized, and the output ports are reset. Next, initial setting processing in step SA2 is performed. In this process, the states (operation modes) of various boards and devices connected to the main control board 200 are initialized, and the copying machine is set to its initial state.

It also sets the mode and count value of the timer 270.

In step SA3, standby mode processing is performed.

At this point, the copying operation is stopped and the copying machine is in a standby state. In this process, the following steps are performed:
First, the states of the signals applied to various input ports are read and the results are stored in the memory 230. Next, a group of data for output control previously stored in the memory 230 is associated with each data. output to the specified output port and control the device connected to that output port. Furthermore, the states of various input ports that have been read in advance and stored in the memory 230 are determined, and the presence or absence of an abnormality is checked. If there is an abnormality, predetermined abnormality processing is executed. If there is no abnormality,
The state of other input ports is determined, and input from the operation board 310 is processed, for example. In this process, the state of a mode switch (DIP switch: not shown) provided in the operation board 310 is determined, The contents of subsequent processing are determined according to the results. Next, it is determined whether or not there is key human power, and if there is key human power, processing is performed in accordance with that key human power. For example, in the normal operation mode, when there is an input from the numeric keypad KIO, the numerical value associated with the pressed key is stored in the copy number register. Further, when there is an input from the magnification adjustment keys 6 a, 6 b, etc., a magnification adjustment instruction signal is sent to the optical system control board 320.

The display data stored in the memory 230 in advance is output to a predetermined output port at a predetermined timing, and the data is displayed on various indicators on the operation board 310.6 The data to be displayed is determined by the state of the mode switch. It can be switched depending on the When the normal operation mode is designated, the number of copies is displayed on the display DI, and the copy magnification is displayed on the display D4.

If the copying is not possible or if the print start key KS is not turned on, the standby mode processing described above is repeatedly executed. Copying is not possible if, for example, the fixing temperature is outside a predetermined range or if some abnormality is detected.

When the print start key KS is pressed in the copy-enabled state, the pre-copy mode process of step SA4 is executed. In this processing, as processing immediately before starting the copying process, the driving start of the main motor, the pre-copying cleaning processing of the photosensitive drum, the paper feeding processing, etc. are performed.

When step SA4 is completed, copy mode processing of step SA5 is executed. At this point, the copy process is actually executed. This processing includes copy process processing 9.
Paper transport processing, toner replenishment processing.

This includes abnormality check processing, etc. In the copy process, various process elements are controlled on/off at predetermined timings synchronized with output pulses from a timing pulse generator that generates pulses corresponding to the amount of rotation of the main motor. If a plurality of copies are to be made continuously, the copy mode process in step SA5 is repeatedly executed.

When the copy mode process of step SA5 is completed for the final copy, the post-copy mode process of step SA6 is executed. In this process, the paper on which the copied image has been transferred is ejected, the photoreceptor drum is cleaned after copying, etc. When the paper II' is completed, the process returns to the standby mode process of step SA3.

Repeat the above process.

The density check process for creating a toner image of the reference density pattern PP on the photosensitive drum 2 is included in the copy process process of the copy mode process SA5.

The contents of this process will be explained with reference to FIG. 6e and FIG. 8 shown in FIG. 6e.

This process is executed while referring to the contents of the timing pulse counter TP that counts the output pulses of the timing pulse generator.

When the timing pulse counter TP reaches 85, check the flag Fp■. When Fp+s is ``1'', the eraser 4 is controlled so that charges only outside the A5R region are erased. In this example, the flag Fpm is
It is set to II, and is reset to 0 at other times.

When the timing pulse counter TP reaches 106.

The eraser 4 is controlled so that charges in the entire area (full width) are erased. Note that even when TP is less than 85, the setting is made such that the entire width of the charge is erased.

Therefore, when the content of Tp is between 85 and 106, charge erasure in the reference pattern forming area is prohibited, so that a toner image corresponding to the base $ density pattern PP is formed in that area. In this example, the content of counter TP is 85.
The timing between and 106 corresponds to approximately 20 mm of length on the photoreceptor drum surface.

However, since the flag Fp- is set to 11'' in 1 out of 10 copy processes, the toner image of the standard density pattern is actually formed on the photoreceptor drum.
Only once in every 10 copies.

When the timing pulse counter TP reaches 125.

, · Check the °゛ flag Fpn. When Fp+m is #1'', - turns on the light emitting diode of the sensor PSEN, sets the flag Fpon to "l", and sets the flag Fp
Set cr to 111" and start the 3m5ec timer. From now on, every 3m5ec, the 6th b
Interrupt processing INTT3 shown in the figure is executed.

When the timing pulse counter TP reaches 1038, the light emitting diode of the sensor PSEN is turned off and the flag F p
Reset on to 0''.

Next, the timer interrupt processing TNTT3 shown in FIGS. 6b, 6c, and 6d will be explained.

In this process, the flag Fpcr is first checked.

The flag Fpcr is set to 1" when step SE8 in FIG. 6e is executed.
If it is II, then check the flag F pon. This flag F_pan also becomes HI in step SE8 of FIG. 6e.
It is set to 11.

If the flag F pon is "1'', step SB3
Execute the process. In this process, the data obtained by A/D converting the output signal level of the sensor PSEN is processed.The A/D converted data is stored in the register DB.
Stored in INF. Then, in the subroutine SB3, each register WDVSG7°WDVSG6. WDVSG
5. WDVSG4゜WDVSG3. WDVSG2. W.D.
VSGl.

WDVSP8. WDVSP7. WDVSP6゜WDVS
P5. WDVSP4. WDVSP3゜WDVSP2. W
The contents of DVSP1 and DBINP(7) are stored in registers WDVSG8°WDVSG7. WDVSG6
．． WDVSG5゜WDVSG4. WDVSG3. WDV
SG2゜WDVSGI, WDVSP8. WDVSP7゜WDVSP6. WDVSP5. WDVSP4゜WDVS
P3. Transfer to WDVSP2 and WDVS P1 in turn.

Therefore, when the process of step SB3 is repeated, register WDVSG8. WI) VSO4, WDVSG6゜W[)
VSO4, WDVSG4. WDVSG3゜WDVSG2
．． WDVSGI, WDVSP8゜WDVSP7. WDV
SP6. WDVSP5゜WDVSP4. WDVSP3.
Latest, past 16 for WDVSP2 and WDVSPI
The data obtained from each batch of sampling is stored. Note that in this example, one piece of sampling data is composed of 8 bits.

Next, check the counter CNchv. This counter CNchv is the output level Vsg of the sensor PSEN.
It is used to determine the switching from Vsp to Vsp (see FIG. 9). Since CNchv is initially 0, the process advances to the next step SB5. And the latest numbering data, namely the contents of DBINP.

Compare with fixed value Vch. As shown in FIG. 9, this value Vch corresponds to an intermediate level between the normal Vsg level and the vsP level. Here, the voltages Vgg and Vsp correspond to the light reflectance of the photoreceptor drum surface □ and the light reflectance of the toner image of the reference density pattern formed on the photoreceptor drum, respectively.

Immediately after the start of density measurement, a position upstream of the reference pattern forming area (see FIG. 8) on the photosensitive drum faces the sensor PSEN. At that position, the charge is erased by the eraser 4 and toner does not adhere even after passing through the developing section, so at that timing, the sensor PSEN
detects the light reflectance of the surface of the photoreceptor drum 2. In that case, the output level of sensor PSEN is usually about 4V. Therefore, since D B I N P > Vch, the counter CNchv becomes 0 in step 5BII.
cleared.

While DBINF>Vch, the counter CNchv becomes O in step 5BII every time this timer interrupt process INTT3 is executed, so the process advances to step SB5 after step SB4.

When DBINF≦Vch, the counter CNchv is incremented at step SB6, and the next step SB
Proceed to 7 a When CNchv≧3, that is.

After sampling is performed three times after DBINF≦Vch, the process advances to step SB8.

In step SB8, the data buffer (register WDV
SG8~WDVSG I and WDvSP8~WDVSP
I). The oldest 8 data out of 16 sampling data, that is.

The average value is calculated using the contents of registers WDVSG8 to WDVSGI(7). The result of that calculation is.

Store in Vsg average value register MvSg. In addition, the calculation result is stored in a predetermined display register and Vs
The average value of g is displayed on the display D1. however.

It is actually displayed when that display mode is selected by the DIP switch.

Next, the process proceeds to step SB9, where the contents of the register Mvsg and the fixed value Vch are compared (0) Normally, the average level corresponding to the light reflectance of the photoreceptor surface is stored in the register Mvsg, so Mvsg)Vch. If M vsg < V ah due to the occurrence of some abnormality,
It is regarded as abnormal and the first step 5B10 is executed. In this process, the abnormality flag F eIIp is set to II II II, and the flags F pcr and F pon are set to II 0.
11, turn off the sensor PSEN, and turn off the display D.
Display t blinking.

Step SB after the value of counter CNchv reaches 3
When step 4 is executed, the process proceeds to step 5B12. Then, the contents of the counter CNcvst are decremented.

The counter CNcvst contains the following information when starting concentration measurement.
16 is set as the initial value.

When the result of decrement becomes O, that is, the counter CN
After the value of chv reaches 3, timer interrupt processing INTT
After executing 3 16 times, proceed to the next step 5BL4.
In that case, 16 V obtained by 16 samplings
sp data is in registers WDvSG8 to WDvSGl
and stored in WDVSP8 to WDVSP1.

In step 5B14, the flag F per is reset to "0" to set the end of the concentration measurement process. In the next step 5B15, the 8-byte buffer register WDv
Exists in SP8 to WDvSP1. Using the new past 8 sampling data, calculate the average value,
The result is stored in register Mvsp as the Vsp average value. Further, the Vsp average value is stored in a predetermined display register.

The average value of Vsp is displayed on the display D4. However, it is actually displayed when that display mode is selected by the DIP switch.

Next, the process proceeds to step 5B16, where the contents of the register Mvsp and the fixed value veI11 are compared. The fixed value Ve■ is set at a relatively high level compared to the normal Vsp level. Therefore, if there are no special abnormalities, M
vsp (Vem), execute the toner supply control in the next step 5B17, and then proceed to step 5B18.
Toner replenishment prohibition flag Ftdl.

Ftd2. Toner replenishment request flag Ftrl, Ftr2
．． Ftr3 and the abnormality flag F emp are reset to O'''.

The contents of the toner replenishment control in step 5B17 above are shown in the 6th f.
and Fig. 6g. First, refer to FIG. 6f. In this process, first, output information from the toner color sensor C3EN is determined to identify the toner color in the developer cartridge.

If the identification result is black toner, change the contents of Mvsg to Mv
Compare with the value 8 times the content of sp. Mvsg>8・Mv
If sp, the toner replenishment request flag Ftr is reset to 10''; otherwise, the flag FF:, r is set to 11''. Similarly.

If the identification result is blue toner, the contents of Mvsg are compared with a value 2.2 times the contents of 1Mvsp.

Mvsg) 2.2. If Mvsp, reset the toner replenishment request flag Fjr to 110 Hl, otherwise set flag Fur to 1". If the result by ffl is green toner, change the contents of Mvgg to Mvsp. Compare with the value twice the content. Mvsg) If 2·MVSP, reset the toner replenishment request flag Fmr to O''; otherwise, set the flag Ftr to "1". If the identification result is sepia toner, the contents of Mvsg are compared with a value 1.8 times the contents of Mvsp.

If Mvsg>1.8-Mvsp, the toner replenishment request flags Ft, r are reset to ``0''; otherwise, the flags Ft, r are set to ``1''.

When the toner replenishment request flag Fjr is set to "1", the toner replenishment renoid is energized at a predetermined timing for a predetermined period of time, and the toner in the toner cartridge 126 is replenished into the hopper 150, thereby determining the amount of toner. Replenishment takes place (not shown). When this quantitative replenishment is completed, the flag Ftr is reset to re O+t.

In other words, in this example, the ratio between the light reflectance of the surface of the photoreceptor drum and the light reflectance of the toner image of the reference density pattern formed on the photoreceptor drum is determined in a binary manner, and the quantitative replenishment of toner is determined. Performs on/off control. This type of developer concentration control is not affected by dirt on the detection surface of the toner image sensor PSEN, variations in the positional relationship between the sensor and the photoreceptor drum 2, and the like, so stable control can be achieved.

Reference is now made to Figure 6g. First, the contents of 1Mvsg are compared with fixed values VA and VB. These fixed values are Mvs
This is a value for determining whether g is an appropriate value, that is, within a normal range, VA is an upper limit value, and VB is a lower limit value. In this example, VA is set to a value corresponding to a voltage of 4.5V, and VB is set to a value corresponding to a voltage of 3V.

If Mvsg>VA or Mvsg(VB,
If it is abnormal, there is no baby, proceed to step SG8 and display D.
1 is blinking and energized to indicate that an abnormality has occurred.

If VA≧Mvsg≧VB, the process proceeds to step SG3, and Mvsg is compared with −Mvsp.

Here, K is a coefficient set depending on the toner color, and in this example, it is set to 4 for black toner. In the case of black toner, in this example.

It is controlled so that Mvgg=8·Mvsp. Therefore, if M vsg < K-M vsp,
This is quite different from the target state, and it is thought that the density of the developer is low.

When M vsg<K-M vsp, step SG
Proceed to step 4 and check the toner end (empty) check flag Fcts. Since F cte is 0'' in the initial state, in that case step SG5
Go to and set Fct,e to 11111. Furthermore, the contents of register Mvsp are stored in register T'Avsp in step SG6, and 1 is set in toner end counter CNte in step SG7.

After this, if the process in FIG. 6g is executed again, the flag F
Since cte is '1'', the process advances to step SG9 after step SG4.Furthermore, the flag Fper is set at a predetermined timing once every 10 copy operations.
I 11, step 5B14 of FIG. 6b.
When executed, the toner replenishment control (SB17) is reset to ``0'', so the toner replenishment control (SB17) is executed only once in 10 copy operations.In other words, it is determined that the developer concentration is low and toner replenishment is performed. If so, step SG9 is executed after toner replenishment and after the copying operation for 10 sheets has been performed.

In step SG9, the previous Mvsp value stored in the register PAvsp and the current Mvsp value are compared. If P Avsp>Mvsp, that is, if the developer concentration does not increase even after toner replenishment, the content of the toner end counter CNje is incremented. Then, the contents of the counter CNta are compared with a predetermined value N. When CNte>H, the display Dt is lit to indicate that the toner supply is exhausted.

PAvsp>Mvsp before CN t,e>N
To become and.

Proceed to step 5G13 and set the flag F cte to # OI
H, and the toner end counters CNt, , e are cleared to 0 in step 5G14.

In step 5B16 of FIG. 6b, M vgp > V e
+m, the process proceeds to FIG. 6d. This will be explained with reference to FIG. 6d.

First, the toner replenishment prohibition flags Ft and dl are checked. If Ftdl is ``1'', the process immediately proceeds to step 5BIO in FIG. 6b. If Ftdl is 0'', then the toner replenishment request flag Fjr2 is checked.

If Ft, r2 are ``0'', then check the toner replenishment request flag Ft, rl, and Ft, rl is ``o''.
” then set it to 111, j and step SD
Proceed to step 6, store the contents of Mvsp in PAvsp, and set the toner replenishment request flag FI1. Set r to +i 1 Hl and proceed to step 5BIO of Figure 6b. Step S
If Ft and rl are 'l'' in D3, the contents of the registers PAvsp and Mvsp are compared.

If PAvsp≦Mvgp, proceed to step SD5, set the flag Ft, r2 to ``1'', store the contents of Mvsp in PAvsp, set the toner replenishment request flag Ft, r to It171, Proceed to step 5BIO of Figure 6b. P Av in step SD4
If sp>Mvsp, the process proceeds to step SD9, where the flags Ftrl and Ftr2 are reset to 'O', and the process proceeds to step 5BIO in FIG. 6b.

If the flag Ftr2 is rr 1 in step SD2, the process proceeds to step SD8, where PAvsp and Mvsp are compared. If P Avsp> Mvsp, proceed to step SD9 and set the flags Ftrl, Ft, and r2 to II.
Reset to OII and proceed to step 5BIO of Figure 6b.

If PAvsp≦Mvsp in step SD8, the toner replenishment request flag Ftdl is set to 'l' and the process proceeds to step 5BIO in FIG. 6b.

If the flag Fan is "0" in step SB2 of FIG. 6b, the process proceeds to the process of FIG. The measurement end timing (T p
= 1038) and the flag F pon is reset, that is, when a toner image of the reference density pattern is generated on the photoreceptor drum but cannot be detected.

This will be explained with reference to FIG. 6c. First, the maximum value FFh (in hexadecimal notation) is stored in the Vsg display register, and the 0th order toner replenishment prohibition flag Ftd2, which indicates that Vsg is abnormal, is checked on the display D1. Ftd2
If is 11111, immediately proceed to step 5BIO in Figure 6b.
Proceed to.

If flag Ft, d2 is It O#l, step SC3
Proceed to.

Check the toner replenishment request flag Fjd3. If the flag F jr3 is 110 #l, it is set to ``1'', the toner replenishment request flag Ft, r is set to 11111, and the process proceeds to step 5B10 in FIG. 6h.

If the flag F rr3 is 111 in step SC3, then the toner replenishment prohibition flag F11. d2 is set to "1", the toner replenishment request flag F is set to 11", and the process proceeds to step 5BIO in FIG. 6b.

The process shown in FIG. 6C is a process of monitoring whether an abnormality occurs continuously when an abnormality is detected in step SB2. Toner is replenished up to 2 times, but 3 times
If the abnormality occurs twice in a row, toner will not be replenished from then on.

Further, the process shown in FIG. 6d is executed when the toner image of the reference density pattern can be detected, but the detected pattern density is too low. In this process, toner is replenished when it is determined that the toner is light (first time), and if the toner is not darker than the previous detection at the second check timing, toner is replenished again, and the third check is performed. If the concentration is higher than the previous detection at the timing,
That is, when an abnormality is detected three times in a row, it is regarded as a complete abnormality and toner replenishment is prohibited.

FIG. 10a and FIG. 10g each show a modification of the process corresponding to FIG. 6g of the above embodiment.

These modifications are simplified versions of the process shown in FIG. 6g. Therefore, a description of these processes will be omitted.

[Effects] As described above, according to the present invention, a toner image corresponding to a reference density pattern is formed on a photoconductor, and toner replenishment is controlled according to the ratio of the light reflectance of the toner image to that of the photoconductor surface. Therefore, the relationship between the original image density and the copy image density can be maintained stably. In particular, even when a color toner is used as the ll1fI4 agent, since the control parameters are automatically corrected, there is no need to operate a switch or the like when changing the toner color, resulting in good operability.

[Brief explanation of drawings]

FIG. 1 is a front view showing the interior of one type of copying machine embodying the present invention. FIG. 2a and FIG. 2b each show the developer cartridge 5.
FIG. 2 is a perspective view and a vertical cross-sectional view. Figure 2c, Figure 2e, Figure 2f and Figure 2h. 29 is a perspective view showing a drive system, a developer transport unit, a toner cartridge, and a shutter plate 170 inside the developer cartridge 5 shown in FIG. 28. FIG. Figure 2d is a detailed perspective view of a part of Figure 2c. FIG. 2g is a longitudinal sectional view of one end of the toner cartridge. FIG. 3 is a plan view showing the operation board 310 of the copying machine shown in FIG. FIG. 4 is a block diagram schematically showing the electrical circuit configuration of the copying machine shown in FIG. 1. FIG. FIG. 5 is a memory map showing part of the memory allocation of the main control board 200 of FIG. Figure 6a, Figure 6b, Figure 6C, Figure 6d, Figure 6e,
6f and 6g show the main control board 200 of FIG.
2 is a flowchart showing a schematic operation of the FIG. FIG. 7a is an electrical circuit diagram showing the toner image sensor PSEN. FIG. 7b is a graph showing the relationship between the output level of the sensor PSEN and the image density. FIG. 8 is a timing chart showing the relationship between process control timing and the position of the electrostatic latent image on the photoreceptor drum. FIG. 9 is a waveform diagram showing the signal waveform output from sensor PSEN. Figures 10a and 10b are flowcharts of modifications of the present invention, respectively. 1: Contact glass 2: Photosensitive drum (charge carrier) 3: Main charger 4: Eraser 5: Developing cartridge (developing means) 7: Transfer charger 8: Separation charger 12: Fixing devices 21 to 24: Paper feed cassette 25: Paper feed tray 30: Optical scanning system (exposure means) 31: Exposure lamp 41: Light shielding plate 60: Automatic document feeder 70: Sorter 80; Automatic double-sided processing device 120: Fixed magnet group 121: Developing sleeve 122:
Developer stirring impeller 123; Developer conveying screw 124: Toner supply rod (toner supply means) 125: Case 126: Toner cartridge 127: Toner supply bar 200: Main control board (electronic control means) C3EN: Toner color sensor (color Detection means) PP: Reference density pattern (reference pattern) PSEN:)-ner image sensor (optical detection means) Dl ~05. Os, Dg, Dd, DP+
at, Del: Display, *7a, 7b, PSEthm, 9. 8゜shi

Claims (4)

[Claims] (1) Charge carrier; Charging means for charging the charge carrier; Exposure means for scanning a predetermined reading area and exposing the charge carrier with light according to the image of the document located within the area; multiple colors; a developing means that selectively utilizes one color of the developer to form a visible image according to the potential distribution on the charge carrier; a color that outputs an electrical signal according to the selected color of the developing means; Detection means; Toner replenishment means for controlling the concentration of developer in the development means; Reference pattern disposed in a part of the reading area of the exposure means and having a predetermined light reflectance; Opposed to the charge carrier. an optical detection means arranged; monitoring the output level of the optical detection means; and detecting the output level of the optical detection means according to the first level and the reference pattern when the non-visible image portion of the charge carrier faces the optical detection means; The toner replenishing means is energized to replenish toner according to the ratio between the visible image formed on the charge carrier and the second level when it faces the optical detection means, and the toner replenishment amount is adjusted between the ratio and the toner replenishment amount. A toner replenishment control device for a copying machine, comprising: electronic control means that adjusts the relationship between the color detection means and the color detection means according to an electric signal output from the color detection means. (2) The electronic control means is configured to control the electronic control means when the ratio between the first level and the second level and the value determined according to the electric signal outputted by the color detection means are in a predetermined relationship. A toner replenishment control device for a copying machine according to claim 1, which performs quantitative replenishment control of a toner replenishing means. (3) When the electronic control means performs the quantitative replenishment control of the toner replenishing means, the electronic control means stores the second level at that time, and thereafter stores the second level corresponding to the light reflectance of the visible image formed by the reference pattern. , a new second level is compared with a stored second level, and the presence or absence of toner is determined according to the comparison result. Device. (4) The electronic control means stores when the ratio between the first level and the second level and the value determined according to the electric signal outputted by the color detection means are in a predetermined relationship; Comparison of the second level with the latest second level, quantitative replenishment control of the toner replenishing means, and processing of storing the second level are performed at the second level where the latest second level is stored. The method is repeated until a level corresponding to a density higher than the level is reached, and when the number of repetitions reaches a predetermined number of times, it is determined that there is no toner.
) A toner replenishment control device for a copying machine as described in item 2.