JP2021113851A - Image forming apparatus - Google Patents

Abstract

To provide an image forming apparatus that can reduce, compared with before, a malfunction until a predetermined timing at which the amount of toner used for image formation and the amount of toner in a toner container become substantially the same.SOLUTION: An image forming apparatus comprises: a latent image carrier; a developing device 50 that develops a latent image on the latent image carrier with toner; a toner container 32 that stores a toner supplied to the developing device 50; a toner supply path from the toner container 32 to the developing device 50; toner amount determination means 111, 56 that determine the amount of toner at a specific portion of the supply path or the developing device; and a toner supply mechanism 91 that supplies toner from the toner container 32 to the supply path. When the toner container 32 is replaced with one that stores a different type of toner, and when a supply condition is satisfied in which the amount determined by the toner amount determination means 111, 56 is less than a predetermined amount, the image forming apparatus starts the supply performed by the toner supply mechanism 91.SELECTED DRAWING: Figure 3

Description

The present invention relates to an image forming apparatus.

Conventionally, a latent image carrier, a developing device for developing a latent image on a latent image carrier with toner, a toner container for accommodating toner to be supplied to the developing device, a toner supply path from the toner container to the developing device, and a toner supply path. An image forming apparatus including a toner amount determining means for determining a toner amount at a specific location of a supply path or a developing device and a toner supply mechanism for supplying toner from a toner container to a supply path is known.
For example, in Patent Document 1, when the image forming apparatus is changed to toner having a different toner particle size and degree of coloration (when the toner container is replaced with one containing different types of toner), the change is made. It describes a solution to the problem that the image density fluctuates while the remaining old toner continues to be used for image formation when the target adhesion amount applied to the toner is changed. The target toner adhesion amount for obtaining the target image density according to the information is changed at a predetermined timing at which the toner used for image formation and the toner in the toner bottle become substantially the same.

However, there is still room for improvement in reducing defects until a predetermined timing when the toner used for image formation and the toner in the toner container become substantially the same.

In order to solve the above-mentioned problems, the present invention comprises a latent image carrier, a developing device that develops a latent image on the latent image carrier with toner, and a toner container that houses toner to be supplied to the developing device. A toner supply path from the toner container to the developing device, a toner amount determining means for determining the amount of toner in the supply path or a specific portion of the developing device, and a toner supply from the toner container to the supply path. When the toner container is replaced with one that accommodates different types of toner in an image forming apparatus including a toner supply mechanism for performing the operation, the amount determined by the toner amount determining means is less than a predetermined amount. It is characterized in that the supply by the toner supply mechanism is started when the condition is satisfied.

It is possible to reduce problems up to a predetermined timing when the toner used for image formation and the toner in the toner container become substantially the same as compared with the conventional case.

The schematic diagram which shows the schematic structure of the printer which concerns on this embodiment. The schematic diagram which shows the schematic structure of the image-forming part. The schematic diagram which shows the toner replenishing device and the toner container set in this. The block diagram which shows a part of the electric circuit in the printer. Explanatory drawing which shows the transition of the toner amount in a sub hopper. Flow chart of control of the printer. A flowchart showing a subroutine of the printer. A flowchart showing other subroutines of the printer. A flowchart showing yet another subroutine of the printer. FIG. 7 is a flow chart of control corresponding to FIG. 7 according to a modified example. The flowchart of the control corresponding to FIG. 8 which concerns on the modification. A flowchart of a subroutine related to the modified example. FIG. 7 is a flow chart of control corresponding to FIG. 7 according to another modification. The flowchart of the control corresponding to FIG. 8 which concerns on the modification. Explanatory diagram of process control. The graph which showed the relationship between the toner density and the number of carriers adhering to a solid image part. The graph which showed the relationship of FIG. 16 about a solid image and a digital halftone image. The graph showing the relationship between the number of carriers attached to the edge portion and the background potential. An example of a digital halftone image.

Hereinafter, an embodiment in which the present invention is applied to an electrophotographic printer (hereinafter referred to as a printer) 1 as an image forming apparatus will be described. First, the basic configuration of the printer according to the embodiment will be described.

FIG. 1 is a schematic diagram showing a schematic configuration of a printer 1 which is an image forming apparatus according to the present embodiment.
In the printer 1, four toner containers 32 (Y, M, C, K) corresponding to each color (yellow, magenta, cyan, black) can be detachably (replaceably) installed on the upper part of the housing. An intermediate transfer unit 85 is provided below the toner containers 32 (Y, M, C, K).

An image forming unit 46 (Y, M, C, K) corresponding to each color is provided in parallel with the intermediate transfer belt 48 of the intermediate transfer unit 85 so as to face the intermediate transfer belt 48 from below. Below the toner container 32 (Y, M, C, K), a toner replenishing device 60 (Y, M, C, K) is provided, respectively. The toner contained in the toner container 32 (Y, M, C, K) is processed by the toner replenishing device 60 (Y, M, C, K) of the image forming unit 46 (Y, M, C, K). It is supplied (supplied) into the developing apparatus 50 (Y, M, C, K) as the developing means.

The four toner containers 32 (Y, M, C, K) corresponding to each color, the image forming unit 46 (Y, M, C, K) and the toner replenishing device 60 (Y, M, C, K) are used. The configuration is the same except that the toner color is different. In the following description and drawings, the subscripts "Y", "M", "C", and "K" indicating the color of the toner to be used will be omitted as appropriate.

FIG. 2 is a schematic diagram showing a schematic configuration of one of the four image forming units 46, 46Y. The image-creating unit 46 includes a photoconductor 41 as a latent image carrier, a charging unit 44 arranged around the photoconductor 41, a developing device 50, a cleaning unit 42, a static elimination unit, and the like. Then, an image forming process (charging step, exposure step, developing step, transfer step, cleaning step) is performed on the photoconductor 41 to form an image of each color on the photoconductor 41.

The photoconductor 41 is rotationally driven clockwise in FIG. 2 by a drive motor. The charging unit 44 uniformly charges the surface of the photoconductor 41 (charging step). After that, the surface of the photoconductor 41 reaches the irradiation position of the laser beam L emitted from the exposure apparatus 47. The exposure apparatus 47 forms an electrostatic latent image corresponding to each color by exposure scanning at this position (exposure step). After that, the surface of the photoconductor 41 reaches a position facing the developing device 50. The developing device 50 develops an electrostatic latent image at this position to form a toner image of each color (development step). After that, the surface of the photoconductor 41 is transferred onto the intermediate transfer belt 48 by the primary transfer portion facing the primary transfer roller 49 with the intermediate transfer belt 48 interposed therebetween (primary transfer step). A color image is formed on the intermediate transfer belt 48 by superimposing and transferring the toner image of each color formed on the photoconductor 41 of each color on the intermediate transfer belt 48.

A small amount of untransferred toner remains on the surface of the photoconductor 41 that has passed through the primary transfer portion. After that, the surface of the photoconductor 41 reaches a position facing the cleaning portion 42. At this position, the cleaning blade 42a mechanically collects the untransferred toner remaining on the photoconductor 41 (cleaning step). Finally, the surface of the photoconductor 41 reaches a position facing the static elimination portion. Here, the static elimination unit removes the residual potential on the photoconductor 41.

The intermediate transfer unit 85 includes an intermediate transfer belt 48, four primary transfer rollers 49 (Y, M, C, K), a secondary transfer backup roller 82, a plurality of tension rollers, an intermediate transfer cleaning unit, and the like. The intermediate transfer belt 48 is stretched and supported by a plurality of tension rollers, and is endlessly moved in the counterclockwise direction in FIG. 1 by the rotational drive of the secondary transfer backup roller 82 among the roller members. Each of the four primary transfer rollers 49 (Y, M, C, K) forms a primary transfer nip by sandwiching the intermediate transfer belt 48 with the photoconductor 41 (Y, M, C, K). ..

Then, a transfer bias opposite to the polarity of the toner is applied to the primary transfer roller 49 (Y, M, C, K). The intermediate transfer belt 48 travels in the direction of the arrow and sequentially passes through the primary transfer nips of the respective primary transfer rollers 49 (Y, M, C, K). In this way, the toner images of each color on the photoconductor 41 (Y, M, C, K) are superimposed on the intermediate transfer belt 48 and primary transfer is performed.

The intermediate transfer belt 48 on which the toner images of each color are superimposed and transferred reaches the secondary transfer portion facing the secondary transfer roller 89. In the secondary transfer unit, an intermediate transfer belt 48 is sandwiched between the secondary transfer backup roller 82 and the secondary transfer roller 89 to form a secondary transfer nip. The four-color toner image formed on the intermediate transfer belt 48 is transferred onto a recording medium P such as transfer paper conveyed to the position of the secondary transfer nip. At this time, untransferred toner that has not been transferred to the recording medium P remains on the intermediate transfer belt 48. After that, the intermediate transfer belt 48 reaches the position of the intermediate transfer cleaning section, and the untransferred toner on the intermediate transfer belt 48 is collected. In this way, a series of transfer processes performed on the intermediate transfer belt 48 is completed.

The recording medium P conveyed to the position of the secondary transfer nip is conveyed from the paper feeding unit 26 arranged below the main body of the apparatus via the paper feeding rollers 26a and 27a, the resist roller pair 28, and the like. Is. Specifically, a plurality of recording media P are stacked and stored in the paper feed units 26 and 27. Then, the paper feed rollers 26a and 27a are rotationally driven in the counterclockwise direction in FIG. 1, and the top recording medium P is fed between the resist rollers and the 28 rollers. The resist roller pair 28 that has stopped the rotational drive temporarily stops the recording medium P that has been conveyed to the resist roller pair 28 by the roller nip. Then, the resist roller pair 28 is rotationally driven in time with the color image on the intermediate transfer belt 48, and conveys the recording medium P toward the secondary transfer nip. In this way, the desired color image is transferred to the recording medium P.

The recording medium P on which the color image is transferred by the secondary transfer nip is conveyed to the fixing device 86. The fixing device 86 fixes the color image transferred to the surface on the recording medium P by the heat and pressure of the fixing belt and the pressure roller. After that, the fixing device 86 feeds the recording medium P between the paper ejection rollers and the rollers 29. The paper ejection roller pair 29 ejects the recording medium P out of the apparatus and sequentially stacks it on the stack portion 30. In this way, the printer 1 completes a series of image forming processes.

Next, the configuration and operation of the developing device 50 in the image forming unit will be described in more detail.
As shown in FIG. 2, the developing apparatus 50 includes a developing roller 51 facing the drum-shaped photoconductor 41, a doctor blade 52 facing the developing roller 51, a first developing agent accommodating portion 53, and a second developing agent accommodating portion 54. It includes two transport screws 55 arranged inside. Further, a toner concentration sensor 56 for detecting the toner concentration in the developer of the first developer housing unit 53 is provided. The developing roller 51 includes a magnet fixed inside, a sleeve that rotates around the magnet, and the like. The developer accommodating portion (53, 54) accommodates a two-component developer G composed of a carrier and toner. The second developer accommodating portion 54 includes a toner supply port 57 formed above the second developer accommodating portion 54.

The sleeve of the developing roller 51 is rotationally driven in the direction of the arrow (counterclockwise) in FIG. Then, the developer G supported on the developing roller 51 by the magnetic field formed by the magnet moves on the developing roller 51 as the sleeve rotates. The developer G in the developing apparatus 50 is adjusted so that the ratio of toner (toner concentration) in the developing agent is within a predetermined range. The toner replenishment device 60 replenishes the toner stored in the toner container 32 into the second developer storage unit 54 via the toner replenishment port 57 according to the toner consumption in the developing device 50. The configuration and operation of the toner replenishment device will be described in detail later.

The toner replenished in the second developing agent accommodating portion 54 circulates in the two developing agent accommodating portions (53, 54) while being mixed and stirred together with the developing agent G by the two conveying screws 55. Then, the toner in the developer G is adsorbed on the carrier by triboelectric charging with the carrier, and is supported on the developing roller 51 together with the carrier by the magnetic force formed on the developing roller 51. The developer G supported on the developing roller 51 reaches the position of the doctor blade 52.

Then, the developer G on the developing roller 51 is conveyed to a position (development region) facing the photoconductor 41 after the amount of the developer is adjusted to an appropriate amount at this position. The latent image formed on the photoconductor 41 adsorbs toner by the electric field formed in the developing region. After that, the developer G remaining on the developing roller 51 reaches the upper part of the first developing agent accommodating portion 53 as the sleeve rotates, and is separated from the developing roller 51 at this position.

FIG. 3 is a schematic view showing a toner replenishing device 60 and a toner container 32 set in the toner replenishing device 60 by taking the one for Y as an example. The toner replenishment device 60 includes a transfer nozzle 611 as a transfer path forming member, a transfer screw 614, a toner drop transfer tube 64, a sub hopper 63 as a storage unit, a bottle side drive mechanism unit 91 as a developer replenishment mechanism, and a sub hopper side drive mechanism unit. It has 92, a supply pipe 61, a supply screw 62, and the like.

When the toner container 32 is inserted into the set cover 608 of the toner replenishing device 60 in the direction of arrow A in the drawing and mounted, the toner replenishing device 60 is mounted on the tip side of the toner container 32 in conjunction with the mounting operation. The transfer nozzle 611 is inserted, and the inside of the toner container 32 and the inside of the transfer nozzle 611 communicate with each other.

The toner container 32 has a cylindrical shape, and includes a container tip cover 34 to be inserted into the set cover 608, a toner bottle 33 integrally formed with a container rotating gear 301, and the like. The container tip cover 34 rotatably holds the toner bottle 33 in a state of receiving the tip portion of the toner bottle 33 in the direction of the rotation axis. The container tip cover 34 includes an ID chip 700 as an information storage unit. The ID chip 700 records data such as the color, composition, characteristics including components of the stored toner, production lot number, and usage status. The set cover 608 is provided with an ID chip connector 701 for making an electrical connection with the ID chip 700. A bar code, a QR code (registered trademark), or the like may be provided instead of the ID chip 700, and a reading means corresponding to these may be provided on the set cover 608.

With the container tip cover 34 of the toner container 32 inserted into the set cover 608 of the toner replenishment device 60, the bottle-side drive mechanism 91 composed of the drive motor, drive gear, etc. is the container rotation gear 301 of the toner container 32. The rotational driving force is transmitted to. As a result, the toner bottle 33 of the toner container 32 is rotationally driven in the direction of arrow B in the drawing while being held by the container tip cover 34. Along with this rotational drive, the spiral protrusion 302 formed spirally on the inner peripheral surface of the toner bottle 33 also rotates. By this rotation, the toner contained in the toner bottle 33 is conveyed from the rear end side to the front end side (from the left side to the right side in FIG. 3) of the bottle. Then, it is supplied from the container tip cover 34 into the transport nozzle 611.

A transport screw 614 as a powder transport member is arranged in the transport nozzle 611, and rotates integrally with a transport screw gear 605 fixed to an end portion in the longitudinal direction thereof. The bottle-side drive mechanism 91 outputs the rotational driving force to the transfer screw gear 605 to rotationally drive the transfer screw 614 to transfer the toner in the transfer nozzle 611.

A toner drop transfer pipe 64 is connected to the downstream end of the transfer nozzle 611 in the toner transfer direction from below in the direction of gravity. The toner conveyed in the transfer nozzle 611 by the transfer screw 614 is dropped from the transfer nozzle 611 into the toner drop transfer tube 64 and gravitationally drops into the sub hopper 63. As a result, toner is replenished in the sub hopper 63. The sub hopper 63 includes a toner amount detection sensor 111 that detects the amount of toner in the sub hopper 63. As the toner amount detection sensor 111, various types of sensors such as a piezoelectric type sensor and a light reflection type can be used.

A supply pipe 61 is connected to the lower part of the sub hopper 63. The sub hopper 63 includes two agitators 66 that are rotationally driven. The two agitators 66 are rotationally driven to convey toner toward the supply pipe 61. The supply pipe 61 includes a supply screw 62 inside. The sub-hopper side drive mechanism unit 92 can independently transmit the rotational driving force to the two agitators 66 in the sub hopper 63 and the supply screw 62 in the supply pipe 61. By rotationally driving the two agitators 66, the toner in the sub hopper 63 is conveyed toward the replenishment pipe 61, and by rotationally driving the replenishment screw 62, the toner in the sub hopper 63 is replenished into the developing apparatus 50. The sub-hopper side drive mechanism unit 92 can be driven independently of the bottle side drive mechanism unit 91.

FIG. 4 is a block diagram showing a part of an electric circuit in the printer according to the embodiment. The control unit 100 has a CPU 101, a RAM 102, a ROM 103, a non-volatile memory, and the like. The control unit 100 controls the drive of each device of the printer, performs various arithmetic processes, and communicates with various sensors. The RAM 102 also stores data of a target voltage VTREF, which is a target value of the output voltage from the toner concentration sensor 56, and control parameters corresponding to process conditions such as charging, exposure, development, transfer, and fixing.

The control unit 100 is electrically connected to each device and sensor of the toner replenishing device 60 (Y, M, C, K) for Y, M, C, and K. Specifically, the bottle side drive mechanism unit 91 (Y, M, C, K) of Y, M, C, K, the sub hopper side drive mechanism unit 92 (Y, M, C, K), the toner amount detection sensor 111 (Y). , M, C, K), ID chip connector 701, etc. are electrically connected. Further, the control unit 100 is also electrically connected to the toner concentration sensor 56 (Y, M, C, K) of the developing device 50 (Y, M, C, K) for Y, M, C, K. Furthermore, an optical sensor (P sensor) 702 that detects the amount of toner applied to the toner image for measurement formed on the intermediate transfer belt 48 for process control, a touch panel, an operation display unit 110 consisting of various keys, and the like are also electrically connected. ing.

The control unit 100 compares the value of the output voltage from the toner concentration sensor 56 (Y, M, C, K) of the developing device 50 (Y, M, C, K) with the target voltage VTREF, and responds to the comparison result. The sub-hopper side drive mechanism unit 92 of the toner replenishment device 60 is controlled so that the amount of toner is supplied from the toner replenishment port 57. Specifically, a control signal is transmitted to the sub hopper side drive mechanism unit 92 (Y, M, C, K) to compare the two agitators 66 in the sub hopper 63 with the replenishment screw 62 in the replenishment pipe 61. It is rotationally driven by an amount that can supply the amount of toner corresponding to the above. By this rotational drive, toner is replenished from the sub hopper 63 into the developing device 50 via the toner replenishment port 57.

Further, the control unit 100 is a toner amount detection sensor 111 (Y, M, C, K) provided in the sub hopper 63 (Y, M, C, K) of the toner replenishment device 60 (Y, M, C, K). When it is detected that there is no toner, the sub hopper 63 (Y, M, C, K) is replenished with toner. Specifically, a control signal is transmitted to the bottle-side drive mechanism unit 91 (Y, M, C, K), and the toner bottle 33 (Y, M, C, K) and the transfer screw 614 (Y, M, K) are transmitted. C, K) are rotationally driven. Toner is replenished to the sub hopper 63 (Y, M, C, K) by this rotational drive. When the toner amount detection sensor 111 (Y, M, C, K) detects the presence of toner, a control signal is transmitted to the bottle side drive mechanism unit 91 (Y, M, C, K), and the toner bottle 33 (Y, M) , C, K) and the transfer screw 614 (Y, M, C, K) are stopped.

FIG. 5 is an explanatory diagram showing a transition of the amount of toner in the sub hopper 63. The area where the toner D exists is shown with hatching. 5 (a) is a full state, FIG. 5 (b) is an estimated toner near end state, FIG. 5 (c) is a confirmed toner near end state, FIG. 5 (d) is a confirmed toner end state, and FIG. 5 (e). Indicates a completely empty state.

The full state of FIG. 5A is a recovery operation executed when the toner container 32 is replaced when the printer is installed or when a notification prompting the toner container 32 to be replaced is given by so-called toner end detection control. This is the state immediately after the return operation). The recovery operation is to replenish the sub hopper 63 with toner from the newly set toner container 32 to return the toner amount of the sub hopper 63 to a predetermined toner amount (for example, full), and to transfer the toner from the sub hopper 63 to the developing device 50. This is an operation of replenishing and keeping the toner concentration in the developing device 50 within a predetermined concentration range. For example, the toner density in the developing apparatus 50 is set to a predetermined reference A (reference density (AWT%) preset to guarantee the image density after the completion of new toner recovery).

The state of the estimated toner near end in FIG. 5B is a state in which the amount of toner in the toner container 32 is estimated to be equal to or less than a predetermined threshold value. The amount of toner in the toner container 32 can be estimated as follows, for example. With the recovery operation and the subsequent toner replenishment operation to the developing device 50 by the toner replenishing device 60, what [G] is in the toner container 32 from the estimated amount of toner discharged from the toner container 32 by the bottle side drive mechanism unit 91. Estimate by calculation whether toner remains. The amount of discharged toner from the toner container 32 can be estimated from the amount of drive of the bottle-side drive mechanism when this discharge is linked to the toner supply accompanying toner consumption. Further, when the driving amount of the bottle-side driving mechanism unit is linked to the toner consumption amount associated with the image forming operation, it can be estimated from the total number of pixels of the formed image or the like. When the estimated toner near-end state is reached, the user is notified by the display of the operation display unit 110 or the like that a new toner container 32 should be prepared.

The state of the confirmed toner near end in FIG. 5C is a state in which it is estimated that the toner in the toner container 32 has run out. It can be estimated that the amount of toner in the toner container 32 has disappeared, for example, as follows. When the toner replenishment operation is continued and the toner in the toner container 32 runs out even after the estimated toner near end is reached, the bottle side drive mechanism unit 91 is driven along with the toner replenishment operation to the developing device 50 by the toner replenishing device 60. Even so, the toner is not discharged from the toner container 32, and the remaining amount of toner in the sub hopper 63 decreases. Whether or not the remaining amount of toner starts to decrease is detected by the toner amount detection sensor 111 (see FIG. 3) received by the sub hopper 63. The toner amount detection sensor 111 detects whether or not the toner is present up to a predetermined height in the sub hopper 63.

Effects such as the time lag from driving the bottle-side drive mechanism 91 to the inside of the toner container 32 through the toner drop transport pipe 64, and the fluctuation of toner distribution in the sub hopper due to the rotation of the agitator 66 in the sub hopper 63. Therefore, in order to avoid accidentally presuming that the toner in the toner container 32 has run out even though the toner still remains in the toner container 32, the bottle side drive mechanism unit 91 is driven and the amount of toner is detected. Reading the output of the sensor 111 is repeated at intervals to detect the presence or absence of toner. For example, when the toner amount detection sensor 111 does not detect toner a predetermined number of times in a row, it is determined to be a confirmed toner near end. do. The bottle-side drive mechanism unit 91 may be continuously driven for a predetermined time before finally determining the final toner near end so as not to leave toner in the toner container 32 as much as possible.

In the final toner near-end state, the toner in the toner container 32 has been used up, but for example, about 4 [G] to 5 [G] of toner remains in the sub hopper 63, and the toner is in a printable state. Therefore, here, the status is set to confirmed toner near end instead of toner end (complete stop). When it is determined that the toner is near-end, the user is notified that there is no toner in the toner container 32 by displaying the operation display unit 110 or the like. In this fixed toner near end, since the toner remains in the sub hopper 63, printing is possible, but it is also possible to replace it with a new toner container 32.

The state of the finalized toner end in FIG. 5D is a state in which it is estimated that almost no toner remains in the sub hopper 63. This estimation can be performed from the amount of toner consumed in the sub-hopper 63 (the amount of toner supplied to the developing device 50) after the final toner near end is reached. For example, it can be estimated from the drive amount of the bottle-side drive mechanism unit. Further, when the driving amount of the bottle-side driving mechanism unit is linked to the toner consumption amount associated with the image forming operation, it can be estimated from the total number of pixels of the formed image or the like. When it is determined that the final toner end has been reached, the printing operation is prohibited, and the user is notified by the display of the operation display unit 110 that the toner container 32 should be replaced.

In the printer 1 of the present embodiment, when the toner container 32 is replaced with one containing different types of toner (for example, those having different toner compositions and components), the amount of toner in the sub hopper 63 as a specific location is a predetermined amount. When the condition that the value is less than or equal to the condition is satisfied, the bottle-side drive mechanism unit 91 starts replenishment. This replenishment corresponds to "supply of developer from the developer container to the supply path". When the amount of toner in the sub hopper 63 is equal to or greater than a predetermined amount, the bottle-side drive mechanism unit does not replenish the toner, thereby preventing the occurrence of problems due to mixing of different types of toner in the sub hopper 63.

FIG. 6 shows a process (S3) of opening and closing the door of the door that opens and closes when the toner container 32 is replaced after executing the device start-up preparation operation (S1) that is executed when the power of the printer 1 is turned on. , Is a flowchart showing the timing of the execution start instruction (S8) of the printing process. When the start-up preparation operation (S1) is completed, the condition is that the door is opened / closed (S2), the power is turned off (S4), the toner is not in the end state, and recovery is not in progress (N in S5 and S6). It is determined whether or not the print instruction has been accepted (S7). When the door opening / closing is detected (Y in S2), the door opening / closing process is started (S3), and when it is determined that the print instruction is received (Y in S7), the printing process is started (S8). When it is determined that the power is turned off (Y in S4), this flow ends.

Control is performed so that the printing operation is not stopped even if printing is in progress when the door that opens and closes when the toner container 32 that is determined to open / close is replaced in S2 is opened. Therefore, in response to the fact that the toner container 32 is in the confirmed toner near-end state shown in FIG. 5C and the operation display unit 110 indicates that there is no toner, printing is interrupted during continuous printing. The toner container 32 can be replaced without. Further, the toner container 32 can be replaced without stopping or interrupting the printing operation even when the state of the estimated toner near end shown in FIG. 5B is not reached.

The toner end flag B is used to determine whether or not the toner is in the toner end state of S5. The toner end flag B (the set state is “1” and the reset state is “0”) is a flag that is set when it is determined that the final toner end state has been reached (S11 in FIG. 8). The recovering flag C is used to determine whether or not S6 is being recovered. The recovery flag C (the set state is "1" and the reset state is "0") is a flag that is set when the start of the recovery process is instructed (S7 in FIG. 7, S10 in FIG. 8). ..

FIG. 7 is a flowchart showing a door opening / closing process related to replacement of the toner container 32. It is executed when there is an instruction to start the processing at the time of opening and closing the door in S3 of FIG. First, it is determined whether or not the toner container 32 has been replaced with another toner container 32 (S1). Even if the door is opened and closed, the user may not operate the toner container 32, or the same thing may only be attached or detached. Therefore, this judgment is made. This determination is made by detection by a sensor provided for detecting attachment / detachment of the toner container 32, detection of electrical interruption and reconnection of the ID chip 700 of the toner container 32, and determination using information read from the storage unit as necessary. be able to. If it has not been exchanged, this flow ends.

When it is determined that the toner container 32 has been replaced with another toner container 32 (Y in S1), the information of the ID chip 700 is read out (S2), and whether or not the toner container 32 has been replaced with the toner container 32 containing different types of toner. Is determined (S3). When it is determined that the toner container 32 containing different kinds of toner has been replaced (Y in S3), it is determined whether or not the toner end flag B is set (S4).

When it is determined that the toner end flag B is set (Y in S4), the end display is stopped (S5), an instruction to start the recovery operation is given (S6), and the recovery flag C is set (S7). , End the process. Since the recovery operation is replenished by the bottle-side drive mechanism unit 91 as a part of the recovery operation, the recovery start instruction (S6) is an instruction to start replenishment by the bottle-side drive mechanism unit 91. The condition that the remaining amount of toner in the sub hopper 63 in the confirmed toner end state is that the amount of toner in the sub hopper 63 is less than a predetermined amount when the toner container 32 is replaced with one containing different types of toner. Will be equivalent to.

When it is determined that the toner end flag B is not set (N in S4), the replenishment stop flag A (referred to as "toner supply stop flag" in the flow; the same applies hereinafter) is set (S8), and the process is performed. To finish. The replenishment stop flag A is set when the driving of the bottle-side drive mechanism unit 91 should be stopped in the subsequent image forming operation. When the toner container 32 is replaced with one containing different types of toner by using the replenishment stop flag A, the toner end flag B is not set, that is, the toner amount of the sub hopper 63 is equal to or more than a predetermined amount. At that time, the subsequent printing operation is executed with the replenishment by the bottle-side drive mechanism unit 91 stopped. As a result, mixing of old and new Nato in the sub hopper 63 is suppressed.

When it is determined that the toner container 32 containing different kinds of toner has not been replaced (N in S3), it is determined whether or not the toner end flag B is set (S9), and the toner end flag B is set. When it is determined that it is set (Y in S9), the end display is stopped (S5), an instruction to start the recovery operation is given (S6), the recovery flag C is set (S7), and the process ends. ..

FIG. 8 is a flowchart showing the printing process. It is executed when there is an instruction to start the printing process in S8 of FIG. First, it is determined whether both the toner end flag B and the recovery flag C have been reset (S1, S2). If either is set (Y in S1 or Y in S2), it is determined whether the accepted printing has been completed (S7), and if not, whether both flags have been reset again. The judgment of is repeated until all of them are reset.

Toner end is set in the middle of continuous printing, and the toner end flag B is set (Y-S8 in S6 to N-S11), or the start of recovery operation is instructed and the recovery flag C is set (in S6). This is a process for restarting the remaining printing after Y-S8 is performed in Y-S9-S2) of FIG. 9 and continuous printing is interrupted.

If it is determined that any of the flags B and C has been reset (N in S1 and N in S2), it is determined whether or not the replenishment stop flag A is set (S3), and if it is set, it is determined. (Y in S3), the printing operation condition is set (S4) so as to stop the driving of the bottle-side drive mechanism unit 91 during the subsequent image forming operation, and the printing operation is executed (S5).

If the replenishment stop flag A is not set (N in S3), the printing operation is executed as it is (S5). Then, the printing operation is executed until it is determined that the final toner end state is reached (Y in S6) or the instructed printing is finished (Y in S7), and the instructed printing is completed. When it is determined (Y in S7), this flow ends. The determination (S6) as to whether or not the final toner end state has been reached is determined by the determination method for the final toner end described with reference to FIG. 5 (d).

When it is determined that the final toner end state has been reached (Y in S6), it is determined whether or not the replenishment stop flag A is set (S8). If the replenishment stop flag A is set (Y in S8), the start of the recovery operation is instructed (S9). That is, as a condition that the toner amount of the sub hopper 63 is less than a predetermined amount and that the state of the final toner end is satisfied, the bottle side drive mechanism unit is instructed to start replenishment as a part of the recovery operation. do. Then, the recovery flag C is set (S10), and the flow is terminated.

If it is determined that the replenishment stop flag A is not set (N in S8), the toner end flag B is set (S11), the toner end display is turned ON (S12), and the flow is terminated. When the toner end flag B is set, the print instruction is not accepted from the control of FIG. 6 (it cannot proceed to S7 because it is Y in S5), and continuous printing is interrupted from the control of FIG. 8 (in S1). I can't proceed to S5 because of Y). That is, the printing operation is prohibited.

FIG. 9 is a flowchart showing the processing of the recovery operation. When the instruction to start the recovery operation is received in S6 of FIG. 7 and S9 of FIG. 8, the execution is executed. First, the recovery operation is executed (S1). When the operation is completed, the replenishment stop flag A, the toner end flag B, and the recovery flag C are reset in S2 to S4 to end the process. Of the flags, the replenishment stop flag A may be in the reset state (0) before processing, but if it is set, it is set to the reset state (0).

According to the above control, when the toner container 32 is replaced with one containing different types of toner, even if the toner amount of the sub hopper 63 is equal to or more than a predetermined amount, the bottle side drive mechanism unit 91 replenishes the toner. The printing operation is executed in the stopped state, and the toner amount of the sub hopper 63 is reduced by replenishing the toner during that period. The printing operation in the state where the replenishment is stopped corresponds to the "operation of reducing the developer at a specific location". Then, when the condition that the toner of the sub hopper 63 is in the state of the toner end as a condition that the amount of toner is less than a predetermined amount is satisfied, the replenishment by the bottle side drive mechanism unit 91 is started.

Therefore, when the toner container 32 is replaced with one containing different types of toner, even if the amount of toner in the sub hopper 63 is equal to or more than a predetermined amount, the sub hopper 63 is replenished by the bottle-side drive mechanism unit 91. It is possible to prevent mixing of different types of toner. Therefore, it is possible to suppress the next problem caused by replenishing the developing apparatus 50 with toner in which different kinds of toner are mixed. That is, it is possible to suppress the occurrence of abnormal images (toner drop, ground stain) and toner scattering due to non-uniformity of toner characteristics (chargeability, fluidity, etc.).

In the above example, it is possible to suppress the situation where different types of toner are mixed in the sub hopper 63, but the toner before replacement remains in the developing apparatus 50. If the toner after replacement is replenished from the sub hopper 63 after the recovery operation into the developing apparatus 50, there is a possibility that a problem may occur due to the mixing of old and new toner in the developing apparatus 50. A modified example capable of suppressing this defect will be described.

FIG. 10 is a flow chart of control corresponding to FIG. 7 according to a modified example. FIG. 11 is a flow chart of control corresponding to FIG. 8 according to the modified example. FIG. 12 is a flowchart of the subroutine according to the modified example. In this modification, when the toner container 32 is replaced with one containing different types of toner, replenishment by the bottle-side drive mechanism unit 91 is started when the condition that the toner amount of the sub hopper 63 is less than a predetermined amount is satisfied. Prior to the recovery operation in which the amount of toner in the sub hopper 63 is restored to a predetermined amount, a toner forced consumption operation as a toner consumption operation in which the toner in the developing device 50 is consumed is performed.

After Y in S4 of FIG. 10, prior to the instruction to start the recovery operation in S6, and after Y in S6 of FIG. 11, prior to the instruction to start the recovery operation in S9, the toner forced consumption operation is performed in AS1, respectively. Execute the subroutine of. In both cases, the execution timing is during the non-image forming operation. Other points are the same as the control described with reference to FIGS. 6-9. When starting the toner forced consumption operation (AS1 in FIGS. 10 and 11), the toner forced consumption operation flag may be set and reset after the operation is completed, and this flag may be used in the same manner as the recovery flag C. ..

FIG. 12 is a flowchart of a subroutine of the toner forced consumption operation according to an example. The machine body holds a consumption recovery count counter that stores the consumption recovery count. First, it is determined whether or not the consumption recovery count counter is smaller than the reference count α. This counter counts the number of executions of a series of consumption recovery operations S2 to S5, and is not smaller than α, that is, when it is determined that the consumption recovery operation has been executed α times (N in S1), this flow is terminated.

In the consumption recovery operation, a forced consumption pattern latent image is created and developed until the toner concentration TC in the developing device 50 detected by the toner concentration sensor 56 becomes equal to or less than the comparison standard toner concentration B (WT%) (development). Operation) to consume toner from the developing device 50 (toner consumption operation) (repeated operation until S2 is determined to be N in S3). The reference value toner concentration B (WT%) for comparison is a toner concentration obtained and set in an experiment or the like. It will be described in detail later. By repeating the creation of the forced consumption pattern α times with the replenishment of toner (accompanied by replenishment as a premise) after the replacement of the predetermined amount in S5, the trouble caused by mixing different types of toner in the developing device 50 does not occur. The toner concentration that can be produced. S4 is a repetition count-up process.

The replenishment of toner after replacement of a predetermined amount in S5 (with replenishment as a premise) is performed before replacement, which is attached to the surface of the member constituting the toner supply path from the toner container 32 including the inside of the sub hopper to the developing device 50. This is done to wash away the toner, so to speak. If the forced consumption pattern is repeatedly created until the toner concentration B (WT%) or less of the comparison standard executed in FIG. 12 is executed while only the toner replenishment operation is performed while the toner filling is stopped, the old sub-hopper 63 is used. It is also possible to make the toner more completely empty (FIG. 5 (e)).

The reference number α is a value determined in advance by using simulation or the like. The larger the reference number α, the more the toner ratio in the developing apparatus 50 is replaced with the changed toner. Specifically, if the reference number α is 1 time, the residual amount of the old toner is about 10%, but if it is 3 times, the residual amount can be set to about 2%, and problems caused by mixing different types of toner can be reliably avoided. .. However, it should be noted that if the reference number of times α is increased, the recovery processing time becomes longer and the machine downtime occurs.

By performing such a toner forced consumption operation, different types of toner are not mixed more in the developing apparatus 50, and the characteristics (chargeability, fluidity, etc.) of the toner do not become non-uniform. Therefore, immediately after recovery. It is possible to further improve problems such as abnormal images (toner drop, background stains) and toner scattering during printing.

In the developing apparatus 50, another modification that can suppress a defect caused by mixing old and new toners will be described. FIG. 13 is a flow chart of control corresponding to FIG. 7 according to a modified example. FIG. 14 is a flow chart of control corresponding to FIG. 8 according to the modified example. In the case of Y in S4 of FIG. 13, unlike the control of FIG. 7, the replenishment stop flag A is set (AS1), the end display is stopped (AS2), and the toner end flag B is set without instructing the start of the recovery operation. Reset (AS3) is performed to end the process. In the case of N in S4, the replenishment stop flag A is set (AS1), and the process is terminated. That is, regardless of whether the amount of toner in the sub hopper 63 is equal to or greater than a predetermined amount or the toner end is reached, the replenishment stop flag A is set to stop the replenishment operation in the subsequent printing operation. ..

Then, while the replenishment stop flag A is set (Y in S6) under the control of the printing process of FIG. 14, the amount of toner in the developing apparatus 50 in S7 reaches the minimum limit at which a normal image can be imaged. Printing is continued while only the toner replenishment operation is performed with the toner replenishment stopped until it is determined that the result has been reached. By comparing the toner concentration threshold value corresponding to this limit with the output of the toner concentration sensor 56, it can be determined whether or not the toner amount limit has been reached. Even if it is determined whether the amount of toner in the developing device has reached the limit by using the threshold value of the parameter related to the image formation condition determined by the adjustment operation (process control control) for image quality instead of the toner density threshold value. good. The threshold value is a value at which a normal image cannot be imaged. The thresholds of the process control control parameters will be described in detail later.

Then, when it is determined that the amount of toner in the developing apparatus 50 has reached the limit due to the continuation of printing (Y in S7), the start of the recovery operation is instructed (S8), the recovery flag C is set (S9), and the step is performed. Proceed to 10. That is, regardless of whether the amount of toner in the sub hopper 63 is equal to or greater than a predetermined amount or the toner end is reached, the toner container 32 is replaced with one containing different types of toner, and the replenishment stop flag A While is set, printing is continued with the toner replenishment stopped, and the recovery operation is started only when the amount of toner in the developing device 50 reaches the limit.

Other points are the same as the control described with reference to FIGS. 6-9. When starting the toner forced consumption operation (AS1 in FIGS. 13 and 14), the toner forced consumption operation flag may be set and reset after the operation is completed, and this flag may be used in the same manner as the recovery flag C. ..

In this modification, after the toner container 32 of different kinds of toner is replaced, the toner replenishment is started by driving the bottle side drive mechanism unit 91 by the recovery operation when the amount of toner in the developing device 50 reaches the limit. ing. Therefore, the inside of the developing device 50 corresponds to a specific location, and the supply condition for the supply start control corresponds to the limit of the amount of toner in the developing device 50. Then, the means for comparing the toner concentration cents and the threshold value for determining whether or not the limit has been reached corresponds to the toner amount determining means.

According to this modification, the toner container 32 containing a different type of toner from the toner currently used at both the timing of the toner end and the timing of not the toner end (during normal use). When the toner is replaced with (the toner is switched), the printing operation is continued without operating the bottle-side drive mechanism unit 91 (including the toner bottle drive).

As a result, from the timing when the parameter related to the image formation condition determined by the adjustment operation (process control control) for the toner density and image quality in the developing device 50 reaches a certain threshold value (threshold value at which a normal image cannot be imaged). The toner recovery operation is performed by starting the driving of the bottle-side drive mechanism unit 91. By the above operation, no matter when the toner bottle is replaced with a different type of toner, the toner before the change and the toner after the change are suppressed from being mixed in the developing apparatus 50, and an abnormal image (toner drop, It is possible to eliminate problems such as ground stains) and toner scattering. Further, since the toner previously in the developing apparatus 50 is used for printing, unlike the examples of FIGS. 10 to 12, wasteful toner consumption due to the toner forced consumption operation can be avoided.

In the above modified example, the bottle side drive mechanism unit 91 is driven regardless of whether the toner is replaced with a toner container 32 of a different type of toner at a timing other than the toner end (during normal use) or at the timing of the toner end. The replenishment operation was stopped (replenishment operation was stopped), the sub-hopper side drive mechanism unit 92 was allowed to be driven (toner replenishment operation), and the recovery operation was performed only when the amount of toner in the developing device 50 reached the limit.

Instead of this, when the replacement timing for the different types of toner containers 32 is not the toner end, the recovery operation is performed only when the amount of toner in the developing device 50 reaches the limit as shown in FIG. 14, and the toner end is performed. In the case of the timing of, the recovery operation may be performed immediately as shown in FIG. It may be operated in the opposite relationship. In these cases as well, at both replacement timings, different toners are mixed in the developing apparatus 50 as compared with the case where the recovery operation is performed at the stage where the amount of toner in the developing apparatus 40 has not reached the limit at the stage of the toner end. Can be suppressed.

FIG. 15 is an explanatory diagram of the process control. Process control is a well-known control called image quality control, image condition adjustment control, image formation condition calculation control, and the like. A pattern latent image for measurement is formed, and the amount of toner adhered (toner development amount) of the developed measurement toner image is determined by the amount of light received by the optical sensor, and various image formation conditions are adjusted. For example, image formation conditions such as charge amount, exposure amount, and development bias are adjusted. Further, the control of correcting the target value of the toner replenishment control using the toner concentration sensor 56 provided in the developing device so that the toner adhesion amount of the measurement toner image becomes a desired amount is also included.

The horizontal axis of FIG. 15 is the development potential, the vertical axis is the amount of toner adhered to the toner image for measurement detected by the optical sensor (P sensor) 702, and the toner states a and b in the developing devices 50 are different from each other. It is a graph showing the relationship between the two. In the toner state a, the development potential for obtaining the target toner adhesion amount T0 exists below the upper limit of the usable development potential range. Therefore, the charge potential, the exposure amount, and the development bias corresponding to the development potential at which the target toner adhesion amount T0 can be obtained can be obtained by adjusting within the usable range (variable range). On the other hand, in the toner state b, the target toner adhesion amount cannot be obtained within the usable range.

Process control is performed at a predetermined timing even during the image forming operation in the toner replenishment stopped state or during the non-image forming operation. Therefore, if it is found that the target toner adhesion amount cannot be obtained within the adjustable range of the image formation condition to be adjusted by the process control in the toner replenishment stopped state, the target toner adhesion amount is obtained unless the recovery operation is performed. It can be determined that the amount of toner is not sufficient. That is, it can be determined that the amount of toner in the developing apparatus 50 as a specific location is less than the amount of toner that can obtain a desired amount of toner adhering. Therefore, it is possible to prevent the image density from being lowered due to the lack of toner by using it instead of detecting the toner density in the developing apparatus 50. The detection of the toner image for measurement by the optical sensor 702 (see FIG. 4) may be performed on the photoconductor instead of on the intermediate transfer belt 48.

FIG. 16 is a graph showing the relationship between the two, with the number of carrier adhesions (the phenomenon in which carriers adhere to the photoconductor together with the toner) that occur when a solid image latent image is developed with the toner concentration on the horizontal axis as the vertical axis. be. As can be seen from this graph, the number of carriers attached to the solid image portion deteriorates as the toner concentration decreases. Therefore, the toner concentration of the comparison standard is such that the number of carriers attached to the carrier when printing the forced consumption pattern is less than the number of carriers attached (N in FIG. 16) so as not to damage parts such as the photoconductor and the photoconductor cleaning blade. It is preferable to determine B.

FIG. 17 is a graph showing the relationship between the toner concentration shown in FIG. 15 and the number of carriers attached to each of the solid image and the digital halftone image. As can be seen from this graph, the number of carriers attached varies depending on the image pattern. Solid portion carrier adhesion is a phenomenon in which carriers adhere to a solid portion, resulting in an image in which the solid portion is white. Solid carrier adhesion occurs because the carrier has a charge of the same polarity as the toner due to electrostatic induction of the electric field in the solid portion, and the carrier develops on the solid portion as it is. This can be improved by increasing the toner concentration and increasing the resistance of the developer.

On the other hand, the edge portion carrier adhesion is a phenomenon in which a carrier having a counter charge adheres to the background of the image edge portion. A strong electric field is generated in the image edge portion due to the edge effect, a large amount of toner is developed, a large amount of countercharge is generated, and an electric field that attracts carriers is also large, so that the image edge portion is a region where adhesion is likely to occur. Edge carrier adhesion can be improved by narrowing the background potential, making carrier development difficult, and reducing the edge effect.

As described above, the solid carrier adhesion in the solid image is due to electrostatic induction, so that the solid carrier adhesion only increases when the toner concentration decreases, whereas in the developed image of the digital halftone latent image. Adhesion of the edge carrier can be reduced by setting the background potential regardless of the toner concentration. Therefore, by creating a forced consumption pattern with a digital halftone image having many edge portions instead of a solid image, it is possible to reduce the toner density B while reducing carrier adhesion during forced consumption. In the case of FIG. 17, the toner concentration corresponding to the number of carriers attached (N in FIGS. 16 and 17) is reduced from B to B'to the extent that the carriers attached to the carriers do not damage parts such as the photoconductor and the photoconductor cleaning blade. be able to.

Since the toner concentration B can be lowered to B'in this way, the residual amount of toner before replacement in the developing apparatus 50 is reduced, so that different types of toner are less mixed and the characteristics of the toner (chargeability and fluidity) are reduced. Etc.) do not become non-uniform, so it is possible to further improve problems such as abnormal images (toner drop, background stain) and toner scattering during printing immediately after recovery.

As shown in FIG. 18, the degree of the number of carriers attached to the edge portion improves as the background potential (difference between the photoconductor charging bias and the developing roller application bias) (image forming condition) decreases. For example, the development bias is the same, and the degree is improved as the charging potential is lowered and the potential is reduced. Therefore, the toner density B can be further lowered by setting the background potential at the time of compulsory consumption pattern image formation lower than that at the time of printing.

From the above, since the toner concentration B can be further lowered, the residual amount of toner before replacement in the developing machine is reduced, so that different types of toner are less mixed and the characteristics (chargeability, fluidity, etc.) of the toner are poor. Since it does not become uniform, it is possible to further improve problems such as abnormal images (toner drop, background stain) and toner scattering during printing immediately after recovery.

FIG. 19 shows an example of a digital halftone image. It is preferable to form such an image for toner consumption with a size in the width direction over the entire width of the image-forming region of the photoconductor.

Although the embodiment using a two-component developer containing toner and a carrier as the developing device has been described above, the embodiment can also be applied to one using a one-component developing agent. In a configuration in which a sub hopper can also be provided between a developing device using a one-component developer and a toner container, mixing of different types of toner in the sub hopper as a specific location can be suppressed as in the embodiment, and the sub hopper can be suppressed as a specific location. It is also possible to suppress mixing of different types of toner in the developing apparatus. In a developing apparatus using a one-component developer, the remaining amount of toner in the developing apparatus can be used instead of the toner concentration. Further, it can be applied to an apparatus for directly supplying toner from a toner container to a developing apparatus using a one-component developer or a two-component developer without using a sub-hopper. In this case, mixing of different types of toner in the developing apparatus as a specific location can be suppressed.

1: Printer 26: Paper feed unit 26a: Paper feed roller 27: Paper feed unit 27a: Paper feed roller 28: Resist roller pair 29: Paper discharge roller pair 30: Discharge stack unit 32: Toner container 33: Toner bottle 34: Container tip cover 41: Photoreceptor 42: Cleaning part 42a: Cleaning blade 44: Charging part 46: Image forming part 47: Exposure device 48: Intermediate transfer belt 49: Primary transfer roller 50: Development device 51: Development roller 52: Doctor blade 53: First developer accommodating unit 54: Second developer accommodating unit 55: Conveying screw 56: Toner concentration sensor 57: Toner replenishment port 60: Toner replenishment device 61: Replenishment pipe 62: Replenishment screw 63: Sub hopper 64: Toner drop Conveyor tube 66: Agitator 82: Secondary transfer backup roller 85: Intermediate transfer unit 86: Fixing device 89: Secondary transfer roller 91: Bottle side drive mechanism unit 92: Sub hopper side drive mechanism unit 100: Control unit 101: CPU
102: RAM
103: ROM
110: Operation display 111: Toner amount detection sensor 301: Container rotary gear 302: Spiral protrusion 605: Conveying screw gear 608: Set cover 611: Conveying nozzle 614: Conveying screw 700: ID chip 702: Optical sensor (P sensor)

Japanese Unexamined Patent Publication No. 2013-44801

Claims (10)

Latent image carrier and
A developing device that develops a latent image on the latent image carrier with toner, and
A toner container that houses the toner to be supplied to the developing device, and
The toner supply path from the toner container to the developing device,
A toner amount determining means for determining the toner amount of the supply path or a specific portion of the developing apparatus, and
A toner supply mechanism that supplies toner from the toner container to the supply path, and
It is an image forming apparatus equipped with
When the toner container is replaced with one containing different types of toner, supply by the toner supply mechanism is started when the supply condition that the determination amount by the toner amount determination means is less than a predetermined amount is satisfied. An image forming apparatus as a feature. In the image forming apparatus according to claim 1,
An image forming apparatus characterized in that when the toner container is replaced with one containing different types of toner, if the supply conditions are not satisfied, an operation of reducing the toner at the specific location is performed. In the image forming apparatus according to claim 2,
An image forming apparatus, wherein the operation of reducing the toner is an execution of an image forming operation in a state where the supply by the toner supply mechanism is stopped. In the image forming apparatus according to claim 2 or 3.
An image forming apparatus, characterized in that, after the supply condition is satisfied by the operation of reducing the toner, the toner supply mechanism supplies a predetermined amount of toner at a specific location. In the image forming apparatus according to claim 4,
An image forming apparatus characterized in that a toner consuming operation for consuming toner in the developing apparatus is performed during a non-image forming operation prior to supply by the toner supplying mechanism for achieving the predetermined amount. In the image forming apparatus according to claim 5,
The toner consuming operation is an image forming apparatus characterized in that a toner consuming operation due to a developing operation of the developing device and a toner supply to the developing device are alternately repeated. In the image forming apparatus according to claim 6,
The image forming apparatus is characterized in that the toner consuming operation is an operation of developing a latent image for the toner consuming operation under an image forming condition in which the background potential becomes smaller than that during image forming. In the image forming apparatus according to any one of claims 1 to 7.
The specific location is in the developing apparatus.
The supply condition is an image forming apparatus, wherein the toner concentration in the developing apparatus is less than a predetermined reference value. In the image forming apparatus according to any one of claims 1 to 8.
The specific location is in the developing apparatus.
An image forming apparatus, characterized in that the amount of toner is less than the amount of toner required to obtain a predetermined toner development amount within a variable range of image forming conditions by process control. In the image forming apparatus according to any one of claims 1 to 9.
Based on the information storage unit provided in the toner container that stores information about the stored toner and the information read from the information storage unit, it is determined that the toner container has been replaced with one that stores different types of toner. An image forming apparatus including a determination means.

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