JPS6327867A - Toner detecting device for copying machine - Google Patents

Abstract

PURPOSE:To eliminate the need for a special mechanism and a sensor for toner concentration detection by detecting the light reflectance of the surface of a photosensitive body and the light reflection factor of the toner image of a reference density pattern formed on the photosensitive body, and performing toner supply control and deciding whether or not there is toner based on the ratio of those two reflection factors. CONSTITUTION:The light reflectance of the surface of a charge carrier and the light reflectance of the visible image of the reference density pattern formed on the surface are detected to perform supply control over toner and decide whether there is toner or not on the basis of the ratio of the both. Namely, the latest eight past sampling data in a buffer register are utilized to compute their mean value, which is stored as a Vsp mean value in a register Mvsp and in a specific display; register and also displayed on a display device. Then, the contents of the register Mvsp are compared with a fixed value (Vem). The Vem is set to a relatively high level as compared with the normal level of Vsp. Therefore, Mvsp<Vem unless there is special abnormality, so toner supply control is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a toner detection device for a copying machine that detects the presence or absence of toner used for forming a visible image in an electrostatic recording copying machine.

[Prior art 1] In an electrostatic recording type 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.

Therefore, if the toner runs out, development will not be possible.
In this type of recording device, it is necessary to detect the presence or absence of toner or the remaining amount of toner, and when the toner runs out or the remaining amount is low, it is necessary to display this and request the operator to replenish the toner. There is.

Therefore, toner detection has conventionally been performed using a first-order detection method.

(a) An electric coil is disposed within the toner replenishment unit, and a change in toner concentration is detected as a change in inductance of the electric coil. (b) Detecting changes in mechanical load applied by toner to a rotating member disposed within the toner supply unit. (c) An optical sensor is provided in the toner supply unit to detect the optical density of the toner.

[Object of the Invention] An object of the present invention is to eliminate the need for a special mechanism or sensor for detecting toner concentration.

[Structure of the Invention] Conventionally, in some copying machines, five copying characteristics (relationship between original density and recording density) are controlled to be constant using the following control method.

A reference density pattern is provided at the end of the document reading surface, and this pattern is read together with the document by a scanner to form an electrostatic latent image on the photoreceptor, and this electrostatic latent image is developed to form a visible image.

Then, the optical reflectance, that is, the density, of the visible image of the group*a degree pattern formed on the photoreceptor is read by a reflective optical sensor. The density of the reference density pattern formed on the photoreceptor is determined by the image reading system.

The light intensity of the exposure lamp and the voltage of the main charger reflect the results of the charging system and development system processes.

Various process elements such as development bias voltage and toner concentration are adjusted so that the reading result of the optical sensor approaches a predetermined state.

In this type of control system, when toner to be replenished runs out, the density of the reference density pattern on the photoreceptor becomes abnormally low even if a predetermined replenishment operation is performed.

Therefore, in order to achieve the above object, in the present invention,
The process of detecting the presence or absence of replenishment toner in a copying machine that employs the control method described above is based on the light reflectance of the surface of the photoreceptor, that is, the charge carrier, and the possibility of the reference density pattern formed on that surface. The light reflectance of the visual image is detected, and toner replenishment control and toner presence/absence are determined according to the ratio of the two. However, if the light reflectance of the photoconductor surface is out of the predetermined range, there is a possibility that the device will malfunction and the presence or absence of toner may be incorrectly determined. Indicates that the rate is abnormal.

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 the drawings.

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 and an ADF (automatic document feeder 1) 6o
, 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
The paper feeding system and the second paper feeding system are provided in the main body of the copying machine, and the second paper feeding unit, which is the third paper feeding system, the fourth paper feeding system, and the fifth paper feeding system are provided in the copying machine main body.
A third paper feeding unit including a paper feeding system is connected to the copying machine main body. 21, 22, 23 and 24 are cassettes provided in the first paper feeding system, second paper feeding system, third paper feeding system and fourth paper feeding system, respectively, and 25 is a tray of the fifth paper feeding system. 6. A contact glass 1 on which a document is placed is provided at the top of the copying machine body, and an optical scanning system 30 is provided below the contact glass 1. 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 1. This reference density pattern PP is a sheet formed with a black pattern having a predetermined light reflectance, and is approximately 20 m in the sub-scanning direction.
It has a length of m.

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 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, and the charge on 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.
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 copy process, recording sheets are fed 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.

Then, the transfer charger 7 transfers the visible image (toner image) on the photoreceptor drum 2 to the recording sheet side, and the separation charger 8 separates the recording sheet to which the visible image has been transferred from the photoreceptor drum 2. The six separated recording sheets are 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. Therefore, when recording an image smaller than A3 size, such as 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, charges in areas other than the image forming area are normally erased by eraser 4 located upstream of developer cartridge 5, as shown in FIG. 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, and erases a portion or the entire electric charge on the photoreceptor drum 2. Possible 0 For example, if the size of the image forming area is 84 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, and all the light emitting elements outside of it are turned on. When the light from one light-emitting element hits, 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.

It 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 before the image forming area. When forming a toner image of the standard density pattern on the photosensitive drum 2, when the standard pattern forming area faces the eraser 4, all the light emitting elements in the area corresponding to the ASR size of the eraser are turned off, and the standard density pattern is formed. Prohibit erasure of

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

Figure 2b, Figure 2c, Figure 2d, Figure 28, Figure 2f,
The developer cartridge 5 will be explained with reference to each time shown in FIGS. 2g and 2h.

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 supported by grasping 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 moving the developer cartridge while engaging the guide rail 113 with a downward guide groove 115 that is integrally formed with the upper case 114 of the developer cartridge, the direction of movement of the developer cartridge at the time of attachment/detachment is determined. is regulated correctly. 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 ends 118 of the support shafts of the developing sleeves into positioning holes 119 on the copying machine main body side. The positioned developer cartridge has 1 handle 11
The hook 112a provided at the base of the copying machine 2 is engaged with an engagement protrusion on the main body of the copying machine, thereby holding the copying machine in its installed position.

FIG. 2b shows an enlarged view of the developing cartridge 5 of FIG. 1. Referring to FIG. 2b, a non-magnetic developing sleeve 121 containing a fixed magnet group 120 is attached to both end plates of the case of the developing cartridge. Developer stirring impeller 122. A developer conveying screw 123 made of a spiral thread and a toner supply 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 bar 127 is provided at the center of the toner cartridge 126, and the toner supply bar 127 is rotatably supported at both ends. Toner supply bar 127
The shaft end at the back is.

It protrudes from the end plate of the toner cartridge, and an engaged body 128 having an fJA tooth 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, one gear 134 has a gear 136 fixed to one end of the toner conveying screw, and the other gear 135 has a gear 136 fixed to one end of the toner conveying screw. .

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/wheels G1 and G on the copying machine main body side.
2, each gear 30.degree. 32-38 is 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 transport plate 141 is
Through the hole 143 formed in 41, the conveying screw 123
The developer that has fallen at one end is transported toward the other end by the transport screw 123, and the receiver is placed in the tray 14.
The developer is returned to one end of the developer stirring impeller 122 from the outlet 145 provided at the end of the developer. Toner transport screw 1
The developer conveying unit 146, which is composed of a conveying plate 141 and a tray 144 that accommodates the developing sleeve 1, has both ends fixed to the case of the developing cartridge.
21 and the developer stirring impeller 122 .

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. A supply rod 12 is provided on both inner surfaces of the lower opening 151 of the hopper 150.
Elongated elastic members 152 and 153 are provided that contact the circumferential surface of 4. These elastic members 152, 153 are 1
Made of synthetic resin material. At the top of the hopper 150,
A swingable tweeter 154 4C is provided. 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 a spring 158, and the arm 156a is attached to the lever 1.
It is lightly pressed against one end 159a of 59 from below.

A pin 160 is fixed to the other end 159b of the lever 159, and the pin 160 is connected to a cam 130a integrated with the gear 130.
The lever 159 is pressed by the force of the spring 61 acting on the lever 159.

The lever 159 is supported by a rib 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. One grip cylinder 166b is integrally formed on one end plate 166, and a lid cylinder 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, When the cartridge 126 is rotated counterclockwise in FIG. 2b, the replenishment port 165 of the cartridge 125 communicates with the upper opening of the hopper 150 and the opening 170a of the shutter plate 170, as will be described later. In this case, the groove 125a
The protrusions 166a and 167a engaged with the case 125
It can rotate along a circumferential groove connected to the groove 125a provided in the groove 125a.

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.
within the range of the closed and open positions of the upper opening of the hopper.

The shirt plate 1 is rotatable along the inner wall surface of the case 121.
I support 70.

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 top plate 170 Jli l 7
2 Opposite a. In this state, toner cartridge 1
When the holding cylinder 166b of No. 26 is grasped and rotated counterclockwise in FIG. When the cartridge 126 is further rotated, the shirt flap plate 170 is aligned with the opening 170a of the cartridge 170 in its final position.
The opening 1170a of the hopper 150 matches the upper opening of the hopper 150.

When removing the toner cartridge 126 from the case 125, rotate the toner cartridge 126 clockwise from the second bg position.
The protrusion 166C pushes the side edge 172a of the protrusion 172 of the shirt flap plate 170, rotates the shirt flap plate 170 in the same direction, and closes the upper opening of the hopper 150. The cartridge 126 has protrusions 166a and 167a that are connected to the case 12.
It rotates to a position where it matches the groove 125a of No. 5, and is pulled out in the axial direction at that position. Therefore, toner cartridge 1
26 is removed from the case 125, the shutter plate 170 closes the entrance 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 each including a 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 copying machine shown in FIG. 1. Referring to FIG. 3, this operation board includes a large number of key switches Kl.

K2. 3. 4a, 4b, 5. 6a.

K6b+ K7. 8+ K9a, 9b, 9ctK
IO, Kl 1. 12a, 12b, K13°KC,
KS, Kg, KI and KT and multiple indicators DI, D2
．． D3. D4. D5. Ds+ DgtDd, 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.

K6 a, 6 b, 9 a, 9 b and 9 c are.

Used to specify 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 the numeric keypad KIO
This is used to clear the number of copies specified and to instruct to stop the copying 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.

DI 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.

D2 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.

In normal operation mode, the copy magnification is displayed in units of 1%.

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 photoreceptor drum is detected in toner detection processing to be described later, the 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.
220. Read/write memory (RAM) 230. Parallel I
10 ports 24o.

Serial I10 boat 250. An 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 35o, automatic document feeder [60, sorter 709, duplex processing device 80° paper feed unit 360. Driver 370, 38
0 and a signal processing circuit 390 are 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.

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 included in the fixing device 12 and the drum heater HT2 included 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+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 that drives the photoreceptor drum 2 and the like, a developer cartridge motor, a Wi feed 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 a 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, boat P o
By controlling ut, the light emitting diode of sensor PSEN can be turned on/off. The output terminal of the phototransistor, that is, the emitter, is connected to the main control board 200 via the analog input port Pin of the main control board 200.
It is connected to the input terminal of the A/D converter 260 inside.

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. It can be seen that as the output level of sensor PSEN increases, the output level of sensor PSEN 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, the CPU initialization process in step SAL is performed first.
In this process, 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, the initial setting process of step SA2 is performed. In this process, the states (operating 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 processing is 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 output control data previously stored in the memory 230 is associated with each data. Output to an 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, determine the status of other input ports, for example, operation board 3.
In this process, the state of a mode switch (DIP switch: not shown) provided in the operation board 310 is determined, and the content of subsequent processing is determined according to the result. . Next, it is determined whether or not there is a key force, and if there is a key force, the process is performed according to the key force. Stores the numerical value associated with the selected key in the copy number register. Further, if there is an input from the 1 magnification adjustment key 6 a, 6 b, etc., a magnification adjustment instruction signal is sent to the optical system control board 320 .

Further, 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 displays on the operation board 310. The data to be displayed is changed according to the state of the mode switch. When the normal operation mode is designated, the number of copies is displayed on the display D1, 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 process includes copy process process 1.
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 copy image has been transferred is discharged, the photosensitive drum is cleaned after copying, etc. When the paper discharge is completed, the process returns to step SA3, the standby mode process.

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 are shown in FIG. 6e. This will be explained with reference to FIGS. 6e and 8.

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, the flag Fp11 is checked. When Fpm is '1'', the eraser 4 is controlled so that charges only outside the A5R region are erased. In this example, the flag FP■ is set to 1'' once every 1e copy processes, and is reset to HO'' 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, erasing of charges in the reference pattern forming area is prohibited, so that a toner image corresponding to the reference 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 Fpm is set to H177 once in 10 copying processes, a toner image of the standard density pattern is actually formed on the photosensitive drum only once in every 10 copies. Only.

When the timing pulse counter TP reaches 125.

Check flag Fpn. When Fp+a is JIn, the light emitting diode of sensor PSEN is turned on, the flag F pan is set to (I 1 u, and the flag F p
er is set to 1" and the 3m5ec timer is started. Thereafter, the interrupt process INTT3 shown in FIG. 6b is executed every 3m5ec.

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 an to '0''.

Next, the timer '111 processing INTT3 shown in FIGS. 6b, 6c, and 6d will be explained.

In this process, first) the lag F per is checked.

The flag Fpcr is set to %##1## when step SE8 in Fig. Ge is executed.
1'', the flag Fpan is checked first.This flag Fpon is also checked in step SE8 of FIG. 6e.
I Set to 11.

If the flag F pan is II I 11, the process of step SB3 is executed. In this process, the sensor PSE
The A/D converted data is processed by A/D converting the output signal level of N.
Stored in BINF. Then, in the subroutine SB3, each register WDVSG7°WDVSG6. W.D.V.S.
G5. WDVSG4゜WDVSG3. WDVSG2. W
DVSG 1゜WDVSP8. WDvSP7. W.D.V.S.
P6゜WDVSP5. WDVSP4. WDVSP3゜W
DVSP2. The contents of WDVSPI and DBINP(7) are stored in registers WDVSG8°WDVSG7.
WDVSGG, WDVSG5゜WDVSG4. W.D.V.S.
G3. WDVSG2゜WDVSGl, WDVSP8. W
DVSP7゜WDVSP6. WDVSP5. WDVSP
4゜WDVSP3. Transfer to WDVSP2 and WDVSPI in turn.

Therefore, when the process of step SB3 is repeated, registers wovsaa, wovsa7. w'ovsc6゜WDV
SG5. WDVSG4. WDVSG3゜WD'VSG2
．． WDVSGI, WDVSP8゜WDVSP
7, W D V S P 6, W D V S
P5.

WDVSP4. WDVSP3. WDVSP2 and WD
Data obtained from the past 16 samplings of Rt new are stored in VSp I. 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). At first, CNchv is 0, so proceed to the next step SB5, and! & Compare the new sampling data, ie, the contents of DBINP, with the fixed value Vch. This value Vch is, as shown in FIG.
This corresponds to an intermediate level between the g level and the Vsp level. Here, the voltages Vsg and Vsp correspond to 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, 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, D B I N F > Vch.

In step 5BII, counter CNchv is cleared to 0.

While DBINF>Vch, the counter CNchv becomes 0 in step 5BIL 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 in step SB6, and the next step SB
Proceed to 7 When mcNchv≧3, that is, DBINF
If sampling is performed three times after becoming ≦Vch,
Proceed to step SB8.

In step SB8, the data buffer (register WDV
SG8~WDVSG 1 and WDVSP8~WDVSP
I). Older 8 data out of 16 sampling data; that is, register WDVSG8~
Using the contents of WDVSG 1, calculate the average value. The result of that calculation is.

Store in Vsg average value register Mvag. In addition, the calculation result is stored in a predetermined display register and Vg
The average value of g is displayed on display WaD1. 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. Normally, the average level corresponding to the light reflectance of the photoreceptor surface is stored in the register Mvsg, so it is Mvsg)Vch. If Mvsg<Vch due to the occurrence of some abnormality, it is regarded as abnormal and the first step 5BIO is executed. In this process, the abnormality flag F e+Ilp is set to II II II, the flags F per and F pon are reset to "0", the sensor PSEN is turned off, and the display Dt is displayed blinking.

Step SB after the value of counter CNehv reaches 3
4, the process proceeds to step 5B12, and the contents of the counter CNcvst are decremented. The counter CNcvst is set to 6 as an initial value when concentration measurement is started.

When the result of decrement becomes 0, that is, the counter CN
After the value of chv reaches 3, timer interrupt processing INTT
3 is executed 16 times, the process advances to the next step 5B14.

In that case, 16 V obtained by 16 samplings
sp data is in registers WDVSG8 to WDVSG
1 and WDvSP8 to WDVSPI.

In step 5B14, the flag F per is reset to 1ON to set the end of the concentration measurement process.The next step 5B137? is an 8-byte buffer register WD
Using the new sampling data for the past 8 times, which exists in VS P 8 to WDVS P l.

The average value is calculated and the result is stored in the register Mvsp as the Vap average value. Further, the Vsp average value is stored in a predetermined display register, and the Vgp average value 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 Ve+w 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, Mv
Since sp(Ve+s), the toner replenishment control of the first step 5B17 is executed, and the process further advances to step 5818.
Toner replenishment prohibition flag Ftdl.

Ftd2. Toner replenishment request flag F jrl, F t
r2. F t, r3 and abnormal flag F ea+p are set to 0.
”.

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, the output information of the toner color sensor C3EN is determined, and the toner color in the developer cartridge is identified.
If the result by m is black toner, the contents of 1Mvag, Mv
Compare with the value 8 times the content of sp. Mvsg)8・Mv
If sp, the toner replenishment request flags Ft, r are reset to "0"; otherwise, the flag Ftr 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 Mvsp.

Mvsg) 2.2.If Mvsp, reset the toner replenishment request flag Fur to 110''; otherwise, set the flag Ftr to 1''. If the identification result is green toner, the content of Mvsg is compared with a value twice the content of Mvsp. Mvsg) 2.Mvsp, the toner replenishment request flag Ftr is reset to rOH; otherwise, the flag Ftr is set to II171. Also,
If the identification result is sepia toner, compare the contents of Mvsg with a value 1.8 times the contents of Mvsp.

Mvsg>1.8・If Mvsp, reset the toner replenishment request flags Ft, r to '0'', otherwise set the flags Ft, r to 1'1''・Toner replenishment request flag Fjr becomes re I II When set, the toner replenishment solenoid 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 performing a fixed amount of toner replenishment (not shown). When this quantitative replenishment is completed, the flag Ftr is reset to II OH.

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 Mvsg 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 it is Mvsg)VA or Mvsg(VB), it is considered that there is an abnormality, and the process proceeds to step SG8, where the indicator DI is blinked and energized to indicate that an abnormality has occurred.

V A'? ;, Mvsg;i: V B If yes, proceed to step S G3 . Then, 1Mvsg and -Mvsp are compared.

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 Mvsg='8·Mvsp.

Therefore, when M vsg<K-M vsp, the state is quite different from the target state, and it is considered that the developer concentration is quite low.

When M vsg < K-M vsp, step S
Proceed to G4 and check the toner end (empty) check flag F cte. Since Fete is “0′” in the initial state, in that case, step S
Proceed to G5 and set F ate to '1''.Furthermore,
In step SG6, the contents of register Mvsp are transferred to register P.
Avsp, and the toner end counter CNje is set to 1 in step SG7.

After this, when the process of FIG. 6g is executed again, the flag Fc
Since te is "1", the process advances to step SG9 after step SG4.Furthermore, the flag Fpcr is set to II at a predetermined timing once every 10 copy operations.
1 #l, and is reset to 110'' when step 5B14 in FIG.
Only once a time. In other words, when it is determined that the developer concentration is low and toner is replenished, step SG9 is executed after toner is replenished and after copying for 10 sheets has been performed.

In step SG9, the previous value of Mvsp stored in the register PAvsp and the current value of Mvsp are compared. The contents of end counters CNt,e are incremented.

Then, the contents of the counter CNt,a are compared with a predetermined value N. When CNts>N (N≧2), the display Dt is lit to indicate that the toner supply is exhausted.

CN te > Before becoming N P AVSP > MV5
When it comes to P.

Proceeding to step 5G13, the flag Fate is reset to On, and in step 5G14, the toner end counter C
Clear Nte to 0.

If Mvsp)Vem is determined in step 5816 of FIG. 6b, the process proceeds to FIG. 6d, which will be described with reference to FIG. 6d.

First, the toner replenishment prohibition flag Ftdl is checked.

If Ftdl is l”, immediately proceed to step 5B in Figure 6b.
Proceed to IO. If Ftdl is '0'', first check toner replenishment request flag Ftr2.

If Ft, r2 are ``0'', first check the toner replenishment request flag Ftrl, set it to 161 if Ftrl is ``Owl'', and proceed to step SD6;
The contents of vsp are stored in PAvsp, the toner replenishment request flag Ftr is set to 111n, and the process proceeds to step 5BIO in FIG. 6b. In step SD3, Ftrl is set to 111n.
If it is 1#, compare the contents of register PAv'sp with the contents of Mvsp.

If PAvsp≦Mvsp, proceed to step SD5, set flag Fjr2 to “l”, and then set Mvsp.
The contents of p are stored in PAvsp, the toner replenishment request flag Ftr is set to 111Hl, and the process proceeds to step S[310 of FIG. 6b. P Avsp> in step SD4
If Mvsp, proceed to step SD9 and set the flag Ftr.
Reset l and F7r2 to 0'' and proceed to step 5BIO of FIG. 6b.

If the flag Ftr2 is #111 in step SD2, the process proceeds to step SD8, where PAvsp and Mvsp are compared. And if P Avsp > Mvsp, step SD
9, the flags Ft, rl and Ftr2 are reset to '0'', and the process proceeds to step 5BIO of FIG. 6b.

If PAvsp≦Mvsp in step SD8, the toner replenishment request flags Ft and cH are set to ``1'', and the 6th b
Proceed to step 5 BIO in the figure.

If the flag Fon is 0'' in step SB2 of FIG. 6b, the process proceeds to the process of FIG. 6c. Note that this process is executed only after the density measurement is started and the reference density pattern (toner image) is found. Before, the measurement end timing (Tp=1
038) 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 1 display Di indicates that the Vsg is abnormal. Next, the toner replenishment prohibition flag Ftd2 is checked. Ft, d2
If is 11111, immediately proceed to step 5BIO in Figure 6b.
Proceed to.

If the flag Ftd2 is 'O', the process advances to step SC3.

Check the toner replenishment request flag Ftd3. If the flag Ft, r3 is "0", it is set to "1", the toner replenishment request flag Ftr is set to "Ill", and the process proceeds to step 5BIO in FIG. 6b.

If the flag Fhr3 is 11" in step SC3, the toner replenishment prohibition flag Ftd2 is set to #J17#,
Set the toner replenishment request flags Ft, r to "1'",
Proceed to step 5BIO of Figure 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.

[Effect] As described above, according to the present invention, the light reflectance of the surface of the photoreceptor and the light reflectance of the toner image of the reference density pattern formed on the photoreceptor are detected, and the ratio of these two light reflectances is determined. Toner supply control and toner presence/absence determination are performed according to the
The conventionally required detection means for detecting the amount of toner in the toner cartridge or the detection means for detecting the developer concentration in the developing device becomes unnecessary.

Since the determination is made according to the ratio of the light reflectance of the photoreceptor surface to the light reflectance of the toner image, highly reliable determination can be made even if, for example, the toner image sensor is dirty or the photoreceptor is deteriorated. Moreover, if the detected value of the light reflectance on the surface of the photoreceptor becomes abnormal, the abnormality is displayed, so that malfunctions can be prevented.

[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@ show the developer cartridge 5, respectively.
FIG. 2 is a perspective view and a vertical cross-sectional view. Figure 2C, Figure 2e, Figure 2f and Figure 2h. 2A 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. 2A. 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. Figures 6a, 6b, 6c, 6d, 6e,
6f and 6g show the main control board 200 of FIG.
2 is a flowchart showing a schematic operation of the FIG. The seventh arM is an electric 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 modified examples 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: @ image side conveyance screw 124: toner supply rod (toner supply means) 125: case 126: toner cartridge 127: toner supply bar 200: main control board (electronic control means) C8EN: toner color sensor ( Color detection means) PP: Reference density pattern (reference pattern) PSEN:) -ner image sensor (optical detection means) DI-05, Os, Dg, Dd, Dp, D
t, Dcl: Display D1: Display (abnormality display means) Voice 7a Figure 7b kfIg Kaneyoshi PSEN*mka, 9. S. ,two

Claims (3)

[Claims] (1) A charge carrier, a charging means for charging the charge carrier,
an exposure means that scans a predetermined reading area and exposes the charge carrier with light corresponding to an image of a document located within the area; and a developer that forms a visible image according to the potential distribution on the charge carrier. an image forming means comprising; a toner replenishing means for controlling the concentration of the developer in the developing means; a reference pattern disposed in a part of the reading area of the exposing means and having a predetermined light reflectance; an optical detection means arranged opposite to the body; an abnormality indicating means; and monitoring the output level of the optical detection means; when a portion of the charge carrier without a visible image faces the optical detection means; When the first level is within a predetermined range, the first level and a second level when the visible image formed on the charge carrier by the reference pattern face the optical detection means. The toner replenishing means is energized to replenish toner according to the ratio of the toner replenishment means, and the presence or absence of toner is determined according to the ratio; when the first level is outside a predetermined range, the abnormality is displayed. A toner detection device for a copying machine, comprising: electronic control means for indicating an abnormality in the means; (2) When the ratio between the first level and the second level reaches a predetermined state, the electronic control means energizes the toner replenishing means to replenish toner, and stores the second level. , after replenishing toner, the current second level is compared with a stored previous second level, and the presence or absence of toner is determined according to the comparison result. Toner detection device for copying machines. (3) When the ratio between the first level and the second level reaches a predetermined state, the electronic control means compares the stored second level with the second level at that time, and controls the toner replenishing means. The process of energizing and storing the second level is repeated until the current second level becomes a level corresponding to a higher concentration than the stored second level, and the number of repetitions is a predetermined number of times. When it becomes, it is determined that there is no toner.
A toner detection device for a copying machine according to claim (2).