JPH01108567A - Control method for image forming device - Google Patents

Abstract

PURPOSE:To obtain an image having a good quality which is free from color mixture by consuming a toner held on the surface of a developing roll to the surface of an electrostatic latent image carrier by detecting a fact that a toner hopper is taken out or installed. CONSTITUTION:When a toner hopper 70 is taken out, a switch S4 is turned OFF, and a photosensitive drum 3 and a developing roller 32 rotate in the direction as indicated with an arrow, respectively. Also, an electrification charger 4 is turned ON, and the surface of the photosensitive drum 3 is electrified uniformly to -600V. Moreover, a developing bias voltage Vb is set to +50V, and a color toner 32 on the developing roller 32 is consumed to the surface of the photosensitive drum 3. In such a way, as for the toner hopper 70, even if a container which has contained a toner whose color is different from the color contained before that time is mounted, it does not occur that the toners of different colors are mixed on the developing roller 32.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of controlling an image forming apparatus having an electrophotographic copying process, such as a copying machine or a printer.

(Prior art and its problems) Conventionally, as a developing device used in the image forming apparatus,
Around the developing roller placed on the side of the photoreceptor drum,
A plurality of toner cartridges each having a toner supply/collection roller facing the developing roller are removably arranged, and toner is supplied from each toner cartridge to the developing roller via the toner supply/collection roller. This was proposed in Japanese Patent Application No. 6212739 by the present applicant, and if this method is used, each toner cartridge contains toner of a different color, and by switching the toner cartridge to be used, a desired color can be obtained. You can get the image.

However, in the developing device, when the toner cartridge is removed and replaced with one containing toner of a different color, if the toner remains on the developing roller, the toner cartridge containing the toner of a different color will be removed from the newly installed toner cartridge. To avoid this situation, the toner is supplied from the developing roller to the original toner cartridge after the development is completed.

However, since the toner collection operation to the toner cartridge is performed while rotating the toner supply/collection roller, toner is supplied in parallel with toner collection.
Toner collection efficiency is poor, and it takes a considerable amount of time to collect. Especially when using a two-component developer consisting of toner and carrier, the toner mixed with the carrier cannot be completely collected, resulting in color mixture in the image. There was a problem.

(Means for Solving the Problems) The present invention has been made to solve the above problems, and includes a developing roller that faces the electrostatic latent image carrier, and a developing roller that is detachably attached to the side of the developing roller. an image forming apparatus comprising: a plurality of toner hoppers each having a toner supply roller; and a developing device that supplies toner contained in the toner hopper to the electrostatic latent image carrier via the toner supply roller and the developing roller. In this case, it is detected that the toner hopper is removed or installed, and the toner held on the surface of the developing roller is consumed on the peripheral surface of the electrostatic latent image carrier.

(Example) Hereinafter, the present invention will be described with reference to the accompanying drawings showing one example thereof.

A. General Structure and Operation of Copying Machine FIG. 1 is a sectional view of the copying machine, and its structure will be explained along with its operation.

Approximately the central shaft of the copying machine body (1) is coated with selenium, for example, on the surface of a cylindrical body made of aluminum (for example, U30m+n).
A photoreceptor drum (3), which is an electrostatic latent image carrier on which zinc oxide, cadmium sulfide, or other organic photoconductor is deposited or coated, is disposed.

This photosensitive drum (3) is rotated in the direction of arrow (a) by the main motor (2) driven by the ON operation of a print switch (not shown), and the surface is heated to a predetermined level by the discharge of the electrostatic charger (4). charged to a potential.

In the optical system (8), an exposure lamp (9) is turned on, and the light is irradiated onto a document (not shown) placed on a document table (14) that scans in the direction of arrow (b), and the reflected light is The photoreceptor drum (3), which is charged to a predetermined potential as described above, is exposed to light from the exposure point (Xl) through the Selfox lens array (12), and the original image is formed on the surface of the photoreceptor drum (3). An electrostatic latent image corresponding to the image is formed.

This electrostatic latent image is supplied with toner at a portion (X2) facing the developing device (5) and is visualized as a toner image. Note that this developing operation will be explained in detail later.

The copy paper (S) is transferred from the paper feed section (20) to the paper feed roller (21).
is fed one by one based on the rotation of the guide plate (22X
23), waits in front of the timing roller pair (24), and moves the transfer area (
X3), and the toner image is electrostatically transferred based on the discharge of the transfer charger (6).

The copy paper (S) onto which the toner image has been transferred is placed on the photosensitive drum (
After being separated from the surface of the copy paper (S), the toner image is transported by a transport belt (25) via a guide plate (26) to a fixing device (27), where the toner image is fused and fixed onto the copy paper (S). The paper is discharged onto the paper discharge tray (28).

After the residual toner on the surface of the photosensitive drum (3) that has passed through the transfer area (X3) is removed by a cleaning device (7), the light from the exposure lamp (9) passes through the opening (10) of the reflective shade (10). 11) and a mirror (13) to irradiate the region (X4) to remove residual charges.

B. Structure, etc. of the developing device (5) Next, the structure, etc. of the developing device (5) will be explained with reference to FIGS. 2 to 4.

As shown in FIG. 1.2, the developing device (5) generally includes a first toner hopper (60) that stores black toner, and a second toner hopper (60) that stores color toner other than the toner (for example, red toner). The toner hopper (70) and a switching mechanism (not shown) move the arrows (c) and (
c'') direction, and move the toner hopper (60) or (70
), and a developing section (30) that selectively receives toner from the photosensitive drum (3) and supplies it to the electrostatic latent image formed on the surface of the photoreceptor drum (3).

1. Developing section (30X, see Figure 3) In the developing section (30), developing frames (31), (3
1) (one not shown) is the photoconductor drum support shaft (■6)
It is rotatably attached to the back and front sides of the

The developing frames (31), (31) are equipped with a developing roller (32).
) is supported by a method described later, and a predetermined gap is formed between the developing roller (32) and the photosensitive drum (3).

The developing roller (32) is made of a conductive non-magnetic material such as aluminum, and minute recesses are formed on the outer peripheral surface by blasting or the like.

Further, inside the developing roller (32), a magnetic roller (3
3) is accommodated, and one end of its spindle is connected to the developing roller (
The other end of the support shaft protrudes from the developing roller (32) and is fixed to the developing frame (31). ) is fixed in a non-rotatable state relative to the

On the other hand, one end of the developing roller (32) has a developing frame (
31), and the other end is rotatably supported by a magnetic roller (31).
3) is rotatably supported on the support shaft.

Therefore, even if the developing section (30) moves along the outer peripheral surface of the photoreceptor drum (3), the magnetic pole of the magnetic roller (33) maintains a constant positional relationship relative to the photoreceptor drum (3). be. That is, the magnetic pole facing the photosensitive drum (3) always faces the photosensitive drum (3).

Also, between the developing frames (31), there is an upper frame (31) that covers the upper and lower parts of the developing roller (32), respectively.
35) and the lower frame (36), and only the portion of the developing roller (32) facing the photosensitive drum (3) and the opposite side thereof are open.

A stirring chamber (38) is formed along the axial direction on the surface of the lower frame (36) facing the developing roller (32), and the developer flows smoothly through the inner surface of the stirring chamber (38) without stagnation. The counterclockwise side wall of the stirring chamber (38) serves as a regulating portion (39) that faces the developing roller (32) with a predetermined gap therebetween.

Furthermore, above and below the developing section (30), there are developing sections (3=7
- Switches (Sl) and (S2) for detecting 0) are installed, and both are connected to a control device (not shown).

As shown in Fig. 3.4, the developing section (30) having the above configuration is operated by a switching mechanism (not shown) to control the developing roller (32).
) is the supply roller (62) of the first toner hopper (60).
), and a color development state (P2), in which the toner hopper (70) faces the supply roller (72) of the second toner hopper (70).

Further, as shown in FIG. 3, the developing section (30), together with the photoconductor drum (3), the charger (4), and the cleaning device (7), is connected to a unit frame ( The imaging unit (IU) is fixed to the copying machine main body (1
) so that it can be attached and detached.

ii. Toner hoppers (60), (70X, see FIG. 2) The toner hoppers (60), (70) supply black toner and color toner to the developing section (30), respectively.

These toner hoppers (60) and (70) are connected to the developing section (30).
) is removably located at the rear of the toner hopper (
Supply rollers (62) and (72) are arranged in the front openings (61) and (71) of the toner hoppers (60) and (70), respectively, and these rollers are rotatable on the side walls of the toner hoppers (60) and (70), respectively. is supported by Further, the supply roller (62),
(72) is located on an arc (L2X2X fourth light) with its center centered on the photoreceptor drum (3), and the supply roller (
62), (72) and the photosensitive drum (3) are closest to each other, and the distance between them is slightly larger than the outer diameter of the developing roller (32).

The supply rollers (62) and (72) are made of a conductive non-magnetic material such as aluminum, for example, like the developing roller, and have four minute portions formed on their outer peripheries by blasting or the like.

Further, regulation blades (64), (74) and toner outflow prevention films (65), (75) are pressed against the rear outer peripheral surfaces of the supply rollers (62), (72), respectively.

Further, the rear portions of the toner hoppers (60) and (70) are arranged such that the supply rollers (62) and (72) and the regulation blade (64)
), (74) and toner outflow prevention film (65), (
toner storage tanks (66) and (76), respectively.
), and a stirring blade (67) is rotatably housed in the toner storage tank (66) of the first toner hopper (60).

Switches (S 3 ) and (S 4 ) are switches for detecting whether or not the toner hoppers (60) and (70) are installed at predetermined positions, respectively, and the signals are outputted to a control device (not shown). It has become.

Stone, drive mechanism (see 120X figures 5 and 6) drive mechanism (1
20), the photoconductor drum drive gear (121) provided on the support shaft of the photoconductor drum (3) is connected to the main motor (2) (
(see Figure 1), and is connected to the developing roller (32
) The developing roller drive gear (122) attached to the spindle of the photoreceptor drum drive gear (
The gears (121) and (122) constitute a differential gear device.

Further, the supply roller drive gear (124) is connected to the support shafts of the supply rollers (62) and (72) via a supply roller drive clutch (127) [the clutch corresponding to the supply roller (72) is not shown]. (126) are attached, and these supply roller drive gears (124) and (126) mesh with idler gears (123) and (125), respectively.

Further, although not shown, the stirring blade (67) provided in the first toner hopper (60) is connected to the supply roller drive gear (12).
4) so as to rotate together with the supply roller (62). Note that the stirring blade (67) may be connected to the drive system of the document table (14) so that it rotates as the document table moves.

In the drive mechanism (120) having the above configuration, the developing section (
30) is set to the black developing state (PL), as shown in FIG. It meshes with the gear (1=11-23).

Therefore, when the main motor (2) is driven in this state and the photosensitive drum drive gear (121) rotates in the direction of the arrow, the developing roller drive gear (122), idler gear (123), and supply roller drive gear ( 124)
rotate in the directions of the arrows, and the photosensitive drum (3) and the developing roller (32) rotate in the directions of the arrows, respectively. Further, when the supply roller drive clutch (127) is turned on by a signal from a control device (not shown), the supply roller drive gear (127) is turned on.
24) is transmitted to the supply roller (62).

When the developing section (30) is switched from the black developing state (Pi) to the color developing state (P2), the developing roller drive gear (12
2) moves around the photosensitive drum drive gear (121) while meshing with it, and meshes with the idler gear (125) of the second toner hopper (70).

Therefore, when the main motor (2) is driven in such a state and the photoconductor drum drive gear (121) rotates in the direction of the arrow, the developing roller drive gear (122), idler gear (125), and supply roller 12 rotate accordingly. = The driving gear (126) rotates in the direction of the arrow, and the photosensitive drum (3) and the developing roller (32) rotate in the direction of the arrow. Further, when a supply roller drive clutch (not shown) is turned on, rotation of the supply roller drive gear (126) is transmitted to the supply roller (72).

iv. Toner density control means (see FIG. 2) Next, the toner density adjustment means supplied to the developing section (30) will be explained.

A developing bias voltage (vb) is applied to the developing roller (32) of the developing section (30), and the supply rollers (62) and (72)
) is the recovery bias voltage (VS) which is the DC bias voltage (Vss) connected in series with the AC bias voltage (Vrms).
is applied, and the bias voltages (Vb) and (Vss) are variable, and by adjusting the voltage value, the toner density on the developing roller (32) can be adjusted.

(2) Developer A two-component developer consisting of toner and carrier is used in the developing device (5) having the above structure.

As the carrier, a binder type carrier having a particle size of 20 to 100 μm, a ferrite carrier, an iron powder carrier, or a carrier whose surface is overcoated with an appropriate resin is used, and the carrier is a developing roller (32).
The magnetic roller (33) is magnetically held on the outer peripheral portion of the magnetic roller (33). Note that the amount of carrier held on the surface of the developing roller (30) is an amount that can be magnetically restrained and held by the developing roller (30). Therefore, even if the imaging unit including the developing section is tilted during attachment, detachment, replacement, etc., the developer on the surface of the developing roller will not be scattered or shifted.

The toner used has a particle size of 5 to 30 μm and is manufactured by a pulverization method or suspension polymerization method, or a capsule toner. As mentioned above, the first toner hopper (60) contains black toner. The second toner hopper (70) contains color toner (for example, red toner) other than the toner.
is accommodated.

C0 Black Developing Operation Below, the specific developing operation using black toner in the first toner hopper (60) will be explained according to the time chart of FIG. 7.

When the developing device (5) is in the thermal developing state (Pl) shown in FIG. 2, when the power switch (not shown) is turned on, the switch (Sl) detects the developing section (30) and turns on. , switches (S 3 ), and (S 4 ) detect the toner hoppers (60) and (70), respectively, and turn on. Note that the switch (S2) is off.

When the print switch (not shown) is turned on in this state, the drive mechanism (120) operates the photoreceptor drum (3) and the developing roller (32) based on the drive of the main motor (2).
, the stirring blades (67) rotate, and the supply roller (62) rotates based on the ON operation of the supply roller drive clutch (127).

Furthermore, the developing bias voltage (vb) is set to -150V and the DC bias voltage (Vss) is set to -200V based on a signal from a control device (not shown).

As a result, in the toner storage tank (66), the stirring blade (6
Based on the rotation of step 7), the black toner is conveyed forward while being mixed and agitated, and at this time, toner prowaking and crosslinking phenomena are prevented.

At the outer periphery of the supply roller (62) facing the toner storage tank (66), the toner sent from the rear is transferred to the supply roller (62).
62) and is conveyed in the direction of the arrow, and excess material is scraped off at the tip contact portion of the regulating blade (64).

The toner taken into the minute recesses is removed by the regulation blade (64
), it is frictionally charged to a positive polarity due to contact with the regulating blade (64), and the supply roller (6
A thin layer of charged toner is formed on the surface of 2).

On the surface of the developing roller (32), the carrier is conveyed in a magnetic brush state along the lines of magnetic force generated by the magnet of the magnetic roller (33), and the thin toner layer is transferred to the supply roller (6).
2) and the developing roller (32).
The scraping action of the brush-like carrier and the developing roller (
Black toner is supplied to the surface of the developing roller (32) based on the voltage difference between bias voltages (Vb) and (Vs) applied to the developing roller (32) and the supply roller (62).

Here, in the area where the developing roller (32) and the supply roller (62) face each other, not only the above-mentioned toner supply operation but also
In parallel, a collection operation is also performed to collect excess toner from the carrier on the developing roller (32) to the supply roller (62).

The toner supplied to the surface of the developing roller (32) is conveyed in the direction of the arrow based on the rotation of the developing roller (32).
First, the two are mixed on the circumferential surface of the developing roller. Next, the developer is transported to the stirring chamber (38), where it is further mixed well and charged to a predetermined value, and then moved to the regulating section (39).
The surface of the developing roller (32) that has passed through the opposing part is coated with toner and carrier at a predetermined ratio (toner concentration: T, = 6~
A two-component developer mixed with 10wL%) is prepared and set to a developable state.

In this state, when the electrostatic latent image formed on the surface of the photoreceptor drum (3) is conveyed to the part facing the developing roller (32), the two-component developer is applied to this electrostatic latent image. It is rubbed and visualized as a black toner image.

The developer that has passed through the part facing the photoreceptor drum (3) is chopped at the part facing the regulating member (39) and most of it falls into the stirring chamber (38). The developer is mixed with the developer mixed in the direction of the arrow while forming a vortex, erasing the toner consumption pattern during development, and some of the developer is again held on the surface of the developing roller (32) and supplied. It is conveyed to the part facing the roller (62),
At this point, toner is supplied again. In addition, the stirring chamber (36)
The inner surface is a smooth curved surface, and the magnetic roller (33)
Since the developer is formed within the range of the magnetic binding force of the developing roller (
32) is constantly mixed and stirred.

When the development operation is completed, the charging charger (4) and the exposure lamp (9) are turned off in sequence, and after a predetermined period of time, the visual bias (vb) is turned off once, and the supply roller (62) is turned off.
The setting value of DC bias voltage (Vss) is 13 under the rotation of
Changed to 00v.

As a result, the developing roller (3
2) The black toner on the top is electrically drawn to the supply roller (6).
2) and is collected in the toner hopper (60),
The toner density on the developing roller (32) is in the standby state (T2=
0-1 to 2.0 wt%).

D. In the developing section switching and toner removal operation method, when the changeover switch (not shown) is turned on, the developing section (30) is moved in the direction of arrow (C') by the switching mechanism (not shown), and the black developing state ( PI) to the color development state (P2). At this time, the developing roller (3
2) is an arc (Ll) centered on the photoreceptor drum (3).
) to move along.

As described above, the developing section (30) is in the heat developing state (Pl).
When the color development state (P2) is changed from the state to the color development state (P2), the switch (S1) is turned off, and then the switch (S2) is turned on. Then, the main motor (2) operates based on the off signal of the switch (Sl), and the photosensitive drum (3),
The developing roller (32) rotates.

At this time, the supply roller drive clutch (not shown) of the supply roller (72) is turned off, and the supply roller (72)
has stopped.

Also, around the photoreceptor drum (3) there is a charger (
4) is turned on, and the surface of the photoreceptor drum (3) is uniformly charged to -600V. Furthermore, the developing bias voltage (v
b) is set to +50V.

As a result, the black toner remaining in the carrier held on the surface of the developing roller (32) is removed from the developing roller (32).
The black toner is conveyed along its outer circumference based on the rotation of the developing roller (32), and is electrostatically supplied to the surface of the photoreceptor drum (3) at a portion facing the photoreceptor drum (3), thereby removing black toner from the outer circumference of the developing roller (32). At this time, the black toner is positively charged and is actively transferred to the photoreceptor drum (3) against the developing bias voltage (vb=+5QV).

The black toner thus supplied to the surface of the photoreceptor drum (3) is conveyed in the direction of arrow (a) based on the rotation of the photoreceptor drum (3) and collected by the cleaning device (7).

When the black toner removing operation described above is carried out for a predetermined period of time and the black toner is almost completely removed from the circumferential surface of the developing roller (32), color development becomes possible.

As a result, black toner is not supplied during color development, and image quality does not deteriorate due to color mixing or the like.

E. Color development operation With the development device (5) set as described above,
When a print switch (not shown) is turned on, the developing bias (vb) is turned on based on a signal from a control device (not shown).
) is -150V, DC bias (Vss) is -200V
are set again.

Next, the photoconductor drum (3) and the developing roller (32) rotate in the direction of the arrow under the drive of the main motor (2), and the supply roller drive clutch (not shown) is turned on to turn on the supply roller ( 72) is rotated. As a result, in the second toner hopper (70), a thin layer of color toner is formed on the outer peripheral surface of the supply roller (72), and the color toner is supplied to the surface of the developing roller (32). A two-component developer of a predetermined concentration (toner concentration: T1'=6 to 1Qwt%) consisting of carrier and color toner is prepared in the outer circumference.

On the other hand, the surface of the photoreceptor drum (3) is connected to the charger (4).
), an electrostatic latent image is formed based on image exposure from the optical system (8), and this electrostatic latent image is supplied with color toner at a portion opposite the developing roller (32). It is visualized as a color toner image.

When the above development operation is completed, in the development device (5), the development bias voltage (vb) and the supply bias voltage (Vs)
is switched, and the toner density on the surface of the developing roller (32) is set to a standby state (Tz'=O-1 to 2.Qwt%).

Next, when the developing section (30) is switched from the color development state (P2) to the black development state (Pi), although not shown in the time chart, the black development state (Pl) is switched to the color development state (P2). Similar to the operation, the developing section (30
) is switched to the black development state (Pl), the switch (S2) detects that the developing roller (32) starts driving, and the color toner remaining on the surface of the developing roller (32) is transferred to the photosensitive drum (32).
3) and is collected by the cleaning device (7). As a result, a state is set in which almost no color toner exists on the outer peripheral portion of the developing roller (32).

Therefore, even if concrete development is performed next time, no color toner will appear on the image.

Note that black toner is generally used more frequently than color toner. Therefore, if color development is completed and color development is not executed again within a predetermined period of time, the developing section (30) may automatically return to the black development state (Pl).

F. Toner hopper attachment/detachment operation Next, regarding the attachment/detachment operation of the toner hoppers (60) and (70), when the developing section (30) is in the color development state (P2), that is, the developing roller (32) is connected to the second toner hopper (70). ), facing the supply roller (72) of
The case of attaching and detaching the toner hopper (70) will be explained.

When the second toner hopper (70) is taken out, the switch (S4) is turned off as shown in the time chart of FIG.
) rotate in the direction of the arrow. In addition, it charger (
4) is turned on, and the surface of the photosensitive drum (3) is uniformly charged to 1,600 μm.

Further, the developing bias voltage (vb) is set to +50V, and the color toner on the developing roller (32) is consumed on the surface of the photoreceptor drum (3) in the same way as the toner removal operation described above.

Therefore, even if a toner hopper (70) containing toner of a different color than the one previously contained is installed, the toner of different colors will not be mixed on the developing roller (32). do not have.

The same is true when the toner hopper (60) is taken out, and this is detected by the switch (S3).The black toner on the developing roller (32) is consumed by the photoreceptor drum, so the toner of a different color is Even if you replace the toner hopper with a toner hopper that accommodates the toner, the image will not be mixed in color.

G. Other Embodiments In the above embodiments, the present invention was applied to a developing device that uses a two-component developer consisting of toner and a carrier, but it can also be applied to a developing device that uses a component developer. Of course it can be done.

Furthermore, in the above embodiment, when removing the toner on the developing roller (30), the surface of the photosensitive drum (3) was charged to -600V as in normal image development. In addition, by applying a developing bias voltage (vb) of the same polarity as the toner (+50 V in the above example, but a voltage higher than that), the toner is transferred from the surface of the developing roller (32) to the photoreceptor drum. (3) You may also make it fly away. Further, by superimposing an alternating voltage on the developing bias voltage (vb) or by increasing the charging potential of the photoreceptor drum (3) to be higher than that during normal development (-600V), the toner removal efficiency can be further improved.

Further, in the embodiment, a toner hopper (60).

(70) is detected to be removed from the developing device (5), and the toner remaining on the surface of the developing rollers (62) and (72) is consumed by the photosensitive drum (3). First, the toner consuming operation may be performed after newly installing the toner hoppers (60) and (70).

(Effects of the Invention) As is clear from the above description, according to the present invention, when the toner hopper is removed or installed, the toner remaining on the surface of the developing roller is consumed on the surface of the electrostatic latent image carrier. Even if you take out the toner and replace it with one containing toner of a different color, toner of different colors will not be supplied to the electrostatic latent image carrier at the same time, and a high-quality image without color mixture can be obtained. Further, the toner held on the developing roller is collected into a toner hopper containing toner of a different color, and different types of toner are not mixed in the toner hopper.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a schematic configuration of a copying machine equipped with a developing device according to the present invention, FIG. 2 is a cross-sectional view of the main part of FIG. 1, FIG. Figure 4 is a sectional view showing the movement of the developing roller, Figure 5 is an exploded perspective view of the drive mechanism,
FIG. 6 is a side view showing the switching state of the drive mechanism, and FIG. 7 is a time chart showing the control of the copying machine. 1... Copying machine main body, 2... Main motor, 3...
Photosensitive drum (electrostatic latent image carrier), 5...Developing device, 7
...Cleaning device, 30...Developing section, 31...
Developing frame, 32... Developing roller, 33... Magnetic roller, 35... Upper frame, 36... Lower frame, 60... First toner hopper, 61.71.
...Opening portion, 62, 72... Supply roller, 70...
second toner hopper, 120... drive mechanism, 121...
... Photoreceptor drum drive gear, 122... Developing roller drive gear, 124, 125... Supply roller drive gear, 1
27...Supply roller drive clutch. Patent Applicant Minolta Camera Co., Ltd. Agent Patent Attorney Aohaku Ao and 2 others

Claims (1)

[Claims] (1) Consisting of a developing roller facing the electrostatic latent image carrier, and a plurality of toner hoppers each having a toner supply roller removably attached to the side of the developing roller, the toner contained in the toner hopper is In an image forming apparatus equipped with a developing device that supplies toner to the electrostatic latent image carrier through a toner supply roller and a developing roller, detecting that the toner hopper is taken out or installed, and holding the toner on the surface of the developing roller. 1. A method for controlling an image forming apparatus, comprising consuming toner on the surface of an electrostatic latent image carrier.