JP3479857B2 - Image forming device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile, a printer, and the like, and more particularly, to a developing apparatus having a plurality of developing devices around a rotation axis. The present invention relates to an image forming apparatus to be rotated. [0002] Conventionally, as an image forming apparatus of this type,
The latent image carrier is exposed to the color separation light image, each formed latent image is developed with a toner of a complementary color of the color separation light, and the obtained plurality of toner images are superimposed and transferred on the same transfer material. Multicolor image forming apparatuses are known. These image forming apparatuses require a plurality of developing units. However, when each developing unit is independently configured and arranged side by side around the latent image carrier, there is a drawback that the apparatuses become large. In view of the above, a rotating body is provided opposite to the latent image carrier, and a plurality of developing units are supported at predetermined positions of the rotating body. By sequentially moving to the developing position, a rotary developing device using a one-component or two-component developer that develops the latent image on the latent image carrier with each color toner has been developed,
It has been put to practical use (for example, see Japanese Unexamined Patent Publication No.
Gazette, JP-A-61-151564, and Jpn.
-153258). In the rotary type developing device, since a portion for storing toner having a predetermined volume is provided in a cross section orthogonal to the longitudinal direction of each developing device, there is a problem that the developing device becomes large. Was. To solve such a problem, Japanese Patent Application Laid-Open No. Hei 6-301 filed by the present applicant has been proposed.
No. 288, a developer container is disposed at one end in the longitudinal direction of the developing device, and the developer is supplied from the developing container to a developer accommodating portion formed at one end of the developing device with the rotation of the developing device. A rotary developing device configured to replenish is disclosed. In each of the rotary developing devices, when the amount of toner in a toner cartridge as a developer container is large, toner is smoothly supplied to a developing device. However, since toner is supplied to the developing device from the toner outlet of the toner cartridge by the gravity acting on the toner, when the amount of toner in the toner cartridge is reduced, even though the amount of toner is still sufficient, The toner is not sufficiently replenished to the developing device, or the toner is ejected from the vicinity of the toner outlet of the toner cartridge due to centrifugal force due to the rotation of the rotary developing device and is not sufficiently replenished to the developing device. It was found that there was a problem that the toner was insufficient. SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to rotate a developer container together with a developing device having a plurality of developing devices and move the developer container from the developing device to the developing device. An image forming apparatus provided with a developing device for supplying a developer to a developer container, wherein a sufficient amount of the developer is supplied to the developer carrying member even when the amount of the developer in the developer container becomes small. To provide an image forming apparatus capable of performing the above. [0007] In order to achieve the above object, the present invention is directed to a developing device in which a plurality of developing devices accommodating a powder developer are arranged around a rotating shaft. , Each developing unit
The wear attached to detachably to rotate integrally with the developing unit, and a developer container containing a developer to be supplied to the plurality of developing units, rotating the developing device around the rotating shaft Then, any one of the plurality of developing devices is moved to a developing position where a developer carrier of the developing device is opposed to the latent image carrier to perform development, and with the rotation of the developing device, In an image forming apparatus in which developer is supplied from an outlet of the developer container to a receiving port of the developing device, a developer amount detecting unit configured to detect an amount of developer in the developer container; Image forming process based on the detection result of the
Control means for controlling the speed of the motor. According to the first aspect of the present invention, the amount of developer in the developer container is detected by the developer amount detecting means, and the detection result of the developer amount detecting means is detected by the control means. The image forming process speed is controlled on the basis of the above, and when the amount of the developer in the developer container is smaller than a predetermined amount, the image forming process speed is reduced. By reducing the image forming process speed in this way, the amount of developer consumed per unit time can be reduced. An embodiment of the present invention is applied to a full-color printer (hereinafter, referred to as “printer”) as an image forming apparatus. An embodiment will be described. First, a schematic configuration of the printer will be described with reference to FIG. A belt-shaped photoreceptor (hereinafter, referred to as a “photoreceptor belt”) 1 as a latent image carrier is uniformly charged by a charging roller 2 as a charging unit, and then converted into image information by a laser optical device 3 as an exposure unit. The surface is scanned and exposed to form an electrostatic latent image on the surface. Here, the image information to be exposed is monochromatic image information obtained by decomposing a desired full-color image into yellow, magenta, cyan, and black color information. This photoreceptor belt 1
The electrostatic latent image formed on the photosensitive belt 1 is developed with predetermined yellow toner, magenta toner, cyan toner and black toner by a rotary developing device (hereinafter referred to as “developing device”) 4 described later. Each color toner image is formed. The photosensitive belt 1 rotates in the direction of arrow A in the figure.
The toner images of the respective colors formed thereon are sequentially transferred onto the intermediate transfer belt 5 rotating in the direction B in the drawing in synchronism with the photoreceptor belt 1 for each of the single colors of yellow, magenta, cyan and black. The yellow, magenta, cyan, and black images superimposed on the intermediate transfer belt 5 are
Are transferred collectively by a transfer roller 9 onto a transfer sheet as a transfer material conveyed to a transfer section via a paper feed roller 7 and a registration roller 8 from the printer. After the transfer is completed, the transfer paper is transferred to the fixing device 1
0 to complete the full-color image. Next, the rotary developing device 4 used in the printer will be described with reference to FIGS. FIG.
2 is a front view showing the internal configuration of the rotary developing device 4. FIG.
A rotary developing device (also referred to as a revolver developing device or a rotary developing device; hereinafter, simply referred to as a “developing device”) 4 is disposed near the photoreceptor belt 1. In the developing device 4, a casing 40 forming a rotating body
Is provided so as to be rotatable about a rotation axis center O, and the casing 40 is rotated in the direction of arrow C by a drive mechanism not shown. Further, the casing 40 has a shape such that the developing device is divided into four parts.
M, C, and K are formed. FIG. 2 shows a state in which one developing unit 41Y is at the developing position. Each of the developing devices 41Y, M, C, and K has a cylindrical developing roller 42Y as a developer carrier.
M, C, and K are provided. Each of the developing rollers 42
Y, M, C, and K are arranged so that a part thereof is exposed to the outside from an opening 41a provided in the casing 40, rotate in the direction of arrow C in the figure in synchronization with the color information, and correspond. Develop the electrostatic latent image. Each of the developing devices 41Y, 41M, 41C, 41K is a developing device using a non-magnetic one-component developer, and contains a yellow toner, a magenta toner, a cyan toner and a black toner, respectively. The electrostatic latent images formed on the photoreceptor belt 1 are sequentially developed by rotating to the developing position selectively at the center, and the respective developed images are superimposed on the intermediate transfer belt 5 and the transfer paper as described above. As a result, a full-color image is formed. FIG. 3 is a front view showing the developing unit 41Y for yellow together with the photosensitive belt 1. Since the developing units 41Y, M, C, and K for the respective colors have the same form and the same operation, only the developing unit 41Y for one color will be described here.
The suffix Y of the code is omitted. In FIG. 3, a developing device 41 is disposed below the photoreceptor belt 1 and supplies toner as a non-magnetic one-component developer to an electrostatic latent image formed on the photoreceptor belt 1 located above the developing device 41. I do. At an opening 41a formed above the developing device 41 at the developing position, a developing roller 42 is provided at a predetermined peripheral speed ratio with the photosensitive belt 1 in the same direction as the photosensitive belt moving direction so as to face the photosensitive belt 1. It is arranged to rotate in the direction (the direction of arrow D in the figure). Below the developing roller 42, a supply roller 43, which is a toner supply member made of an elastic material such as foamed polyurethane, rubs against the developing roller 42 and at a predetermined circumferential position relative to the developing roller 42 at the rubbing portion. It is provided so as to rotate in the same direction (direction of arrow E in the figure) with a speed ratio. Supply roller 43 in the moving direction of developing roller 42
Further downstream, near the opening 41a, a thickness of 0.1
A blade 44 made of a thin metal plate such as stainless steel of about mm or an elastic body such as urethane rubber is provided so that the vicinity of one end thereof is in contact with the developing roller 42. A member denoted by reference numeral 45 in the figure is a first toner conveying screw as a developer conveying unit described later, and conveys the toner from the near side to the far side in the drawing. Further, a toner hopper 46 as a developer accommodating portion is provided in front of the developing device 41. The first toner conveying screw 45 is disposed in parallel with the developing roller 42 and the supply roller 43 from the toner hopper 46 to the other side plate of the developing device 41, and is configured to convey the toner from the front side to the rear side in the drawing. In conjunction with the feed roller 42 and the supply roller 43, the feed roller 43 is rotated at a predetermined peripheral speed ratio. The casing 40 is disposed so that a part thereof is in contact with the supply roller 43, and the first toner conveying screw 45 is formed by the developing roller 42, the supply roller 43, and the casing 40.
Is formed. Then, the first toner conveying screw 45
Is rotated in a predetermined direction, so that the toner hopper 4
From 6, the toner is transported into the toner transport space 47, and the toner is supplied onto the supply roller 43. The toner supplied onto the supply roller 43 is supplied to the surface of the developing roller 42 while being charged by the supply roller 43, and is carried on the surface of the developing roller 42. The toner carried on the surface of the developing roller 42 is made into a uniform and thin layer of toner by a blade 44, and the electrostatic latent image formed on the surface of the photoreceptor belt 1 is developed by contact or non-contact development. By the way, the toner not used in the developing step is transported by the first toner transport screw 45 to the end of the developing device opposite to the toner hopper 46. A space for toner circulation is provided outside the effective diameter portion of the developing roller 42 and the supply roller 43 in the axial direction. The toner transported by the first toner transport screw 45 to the toner circulating portion at the end of the developing device falls to the lower portion of the developing device 41 by gravity. Below the developing device 41, a second toner conveying screw 48 is disposed in parallel with the developing roller 42, the supply roller 43, and the first toner conveying screw 45, and in a direction opposite to the first toner conveying screw 45. The toner is rotated to convey the toner, and conveys the toner not used in the developing process to the toner hopper 46. By appropriately setting the transport amounts of the first toner transport screw 45 and the second toner transport screw 48, the supply roller 43 can be detected without detecting the toner amount in the developing device 41 or performing complicated supply amount control.
It is possible to provide a small-sized developing device which can be supplied on the top, has a large degree of freedom in layout, and has a small sectional occupation ratio with respect to the photosensitive member. The toner cartridge 11 as a developer container is removably mounted on the toner hopper 46 of the developing device 41, and is mounted and replaced when the developing device 4 is newly mounted and when the toner end is reached. The required amount of toner is stored. Next, toner supply from the toner cartridge 11 to the toner hopper 46 will be described with reference to FIG. Since the construction and operation of this toner supply are the same for all the developing units, here, the yellow developing unit 41 is used.
Y will be described. The toner cartridge 11 attached to each toner hopper 46 rotates with the rotation of the developing device 4. Here, for example, the developing device 4 changes from the state shown in FIG. 4A in which the yellow developing unit 41Y is at the developing position to the yellow developing unit 41 through the states shown in FIGS. 4B and 4C.
When Y rotates to the state shown in FIG. 4D at the non-development position, the toner contained in the toner cartridge 11Y mounted on the toner hopper 46Y of the yellow developing device 41Y moves in the toner cartridge 11Y by gravity. Then, as shown in FIG.
In the vicinity of the discharge port 11aY and the toner hopper 46Y. When the developing device 4 further rotates from this state and returns to the state shown in FIG. 4A in which the yellow developing device 41Y is in the developing position, the toner accumulated near the discharge port 11aY is removed as indicated by the arrow. The toner drops into the toner hopper 46Y through the discharge port 11aY and the receiving port of the toner hopper 46Y. According to this configuration, the toner cartridge 11
By providing one rotation of the developing device 4 clockwise, toner can be conveyed from the toner cartridge 11Y to the toner hopper 46Y and replenished without providing any toner conveying member in Y. Next, the control of the first toner transport screw 45 and the second toner transport screw 48 when the remaining amount of toner in the toner cartridge 11Y becomes small will be described with reference to FIGS. As shown in FIG. 5, a toner end sensor 12 as a developer amount detecting means is attached near the discharge port 11aY of the toner cartridge 11Y, and is connected to a printer engine board as a control means (not shown). Toner end sensor 12 detects toner near end (toner is low)
When the developing device 4 rotates as shown in FIGS. 6 (a) to 6 (e) in a state in which the toner cartridge 11Y is detected, the discharge port 11aY of the toner cartridge 11Y and the toner hopper 4 as shown in FIG.
Since the amount of toner near 6Y is small, the toner hopper 46
The amount of toner supplied to Y decreases, and as a result, the rotation of the first toner conveying screw 45 and the second toner conveying screw 48 causes the developing roller 42 and the supply roller 43 to rotate.
The amount of toner conveyed to the printer also decreases. Therefore, when the toner end sensor 12 detects a toner near end (toner is low), the signal is sent to the printer engine board, and the first toner conveying screw 45 and the second toner conveying screw 45 during the subsequent image forming process are executed. The rotational speed of the two-toner conveying screw 48 is controlled to be increased to increase the toner conveying force. As a result, even if the toner in the toner cartridge 11Y is running low, the developing roller 42
In addition, a sufficient amount of toner can be conveyed and supplied to the supply roller 43. In the above example, the toner end sensor 1
The first toner conveying screw 45 based on the detection result of the second
Although the rotation speed of the second toner conveying screw 48 is controlled, the image forming process speed may be controlled instead of the rotation speed of the screws 45 and 48. That is, when the toner end sensor 12 detects the toner near end, the signal is sent to the printer engine board, and at the time of the subsequent image forming process, the image forming process speed is reduced to reduce the toner consumption per unit time. I do. Also with this configuration, when the toner in the toner cartridge 11Y is running low, sufficient toner can be conveyed and supplied to the developing roller 42 and the supply roller 43. Specifically, the first toner conveying screw 4
By halving the linear speed of the photosensitive belt 1, the linear speed of the developing roller 42, and the linear speed of the paper transport system by half while keeping the rotation speeds of the fifth and second toner conveying screws 48, the toner consumption on the developing roller 42 is reduced. Halve the amount of normal time per unit time. At this time, the voltage applied to the charging roller 2 and the transfer roller 9 and the laser exposure amount of the laser optical device 3 and the discharge light amount of the discharge lamp must be changed from a preset value to another value as appropriate. Although there may be cases in which this is not the case, the amount of change can be easily set at the design stage. Further, instead of controlling the rotational speeds of the first and second toner conveying screws 45 and 48 based on the detection result of the toner end sensor 12, the rotational speed of the developing device 4 is controlled. You may. That is, in the toner near-end state, the discharge port 11aY of the toner cartridge 11Y as shown in FIG.
In addition, the amount of toner near the toner hopper 46Y decreases, but the amount of toner above the discharge port 11aY is reduced by inertia as the rotation speed of the developing device 4 increases. Therefore, when the toner end sensor 12 detects the toner near end, the signal is sent to the printer engine board, and during the subsequent image forming process, the rotation speed of the developing device 4 is reduced, so that the toner outlet is located above the discharge port 11aY. The amount of accumulated toner is increased as much as possible to secure the amount of toner supplied to the toner hopper 46Y. At this time, the switching time for the development of each color is longer than that in the normal state, and in order to form an image at the same image forming process speed as in the normal state, development of one color in each color is performed for two rotations of the intermediate transfer belt. Need to be applied. Further, instead of controlling the rotation speeds of the first and second toner conveying screws 45 and 48 based on the detection result of the toner end sensor 12, the toner cartridge is discharged to the center of the rotation shaft of the developing device 4. The position of the outlet 11aY is moved to
You may comprise so that the moving means which changes the rotation radius of Y may be controlled. That is, in the toner near end state, FIG.
As shown in (e), the amount of toner in the vicinity of the outlet 11aY of the toner cartridge 11Y and the toner hopper 46Y decreases, but the amount of toner in the upper part of the outlet 11aY is further reduced due to the inertia caused by the rotation of the developing device 4. turn into. Therefore, when the toner end sensor 12 detects the toner near end, the signal is sent to the printer engine board, and at the time of executing the subsequent image forming process, the discharge port 11aY of the toner cartridge 11Y is moved to rotate the rotation shaft of the developing device 4. Outlet 11a close to center
The turning radius of Y is reduced. Here, since the inertial force acting on the toner is proportional to the rotation radius, the discharge port 11aY
If the rotation radius of the toner is reduced, the amount of toner blown from the vicinity of the outlet 11aY decreases, and as a result, the amount of toner above the outlet 11aY increases and the amount of toner supplied to the toner hopper 46Y increases. More specifically, as shown in FIG. 7B, the position of the discharge port 11aY is variable in the direction of the arrow F in the figure by a lifting device (not shown) as the above-mentioned moving means. Is detected when the discharge port 11a is detected.
The position of Y moves from the position indicated by the solid line in FIG. 7A to the position indicated by the broken line in FIG. 7B. As a result, at the position of the solid line before the movement, the toner near the upper portion of the discharge port 11aY is reduced by the inertia force due to the rotation of the developing device 4 and is reduced.
Since the rotation radius of aY is small, the inertia force applied to the toner is also small, and the amount of toner required for replenishment is secured near the upper part of the discharge port 11aY. In addition, instead of controlling the rotation speed of the first toner conveying screw 45 and the second toner conveying screw 48 based on the detection result of the toner end sensor 12, opening / closing means for opening / closing the discharge port 11aY of the toner cartridge 11Y. May be controlled. That is, when the toner end sensor 12 detects the toner near end, the signal is sent to the printer engine board, and when the subsequent image forming process is executed, the toner discharge port 1 is output.
Control is performed so that 1aY is closed except when facing upward. More specifically, as shown in FIG. 8B, the shutter member 46 of the receiving port 46aY of the toner hopper 46Y
bY can be moved by a slide device (not shown) in the direction of arrow G in the figure. When toner near end is detected, the shutter member 46bY of the receiving port 46aY is detected.
Moves from the position indicated by the solid line in FIG. 8B to a position closing the reception port 46aY, and closes the reception port 46aY. However, the operation is executed except when the reception port 46aY is facing upward.
With the shutter member 46bY of the receiving port 46aY at the position indicated by the solid line before the movement, the receiving port 46aY is rotated during the rotation of the developing device 4.
When Y faces downward, the toner contained in the toner hopper 46Y falls. Here, as shown in FIG. 8A, when there is sufficient toner in the toner cartridge 11Y, a sufficient amount of toner is supplied to the toner hopper 46Y when the receiving port 46aY faces upward.
As shown in (b), when the toner is near the end, the toner to be replenished is small, so that the toner hopper 46Y is not sufficiently replenished. However, if the toner inlet 46aY is closed except when the receiving port 46aY faces upward in the toner near-end state, the toner is not replenished from the toner hopper 46Y but only replenished, so that a sufficient amount of toner is secured in the toner hopper 46Y. Is done. Instead of providing the shutter member 46bY inside the toner hopper 46Y, a shutter member for opening and closing the discharge port 11aY may be provided inside the toner cartridge 11Y. When the toner is not near the end, it is desirable to control the opening and closing of the shutter member 46bY. As a result, it is possible to avoid a situation in which a large amount of toner pressure is constantly applied to the toner in the toner hopper 46Y, and as a result, the toner in the toner hopper 46Y is aggregated to cause a problem in toner conveyance. Further, based on the detection result of the toner end sensor 12, instead of controlling the rotation speeds of the first and second toner conveying screws 45 and 48, control is performed so as to change the volume of the toner cartridge 11Y. It may be configured as follows. That is, when the toner end sensor 12 detects the toner near end,
The signal is sent to the printer engine board, and the volume of the toner cartridge is controlled to be reduced when the image forming process is performed thereafter. More specifically, as shown in FIG. 9B, the outer peripheral wall 11 of the toner cartridge 11Y can be moved in the direction of arrow H in the figure by a slide device (not shown) as a variable capacity means. When the toner near end is detected, the movable circumferential surface 11bY of the toner cartridge is
The position of the solid line in FIG. 9A is moved to the position of the broken line in FIG. 9B to reduce the volume of the toner cartridge 11Y.
Here, the outer peripheral movable wall 11b of the toner cartridge 11Y
When Y is the position indicated by the solid line, the toner near the upper portion of the discharge port 11aY has been reduced due to the inertial force caused by the rotation of the developing device 4, but has been reduced at the position indicated by the broken line after the movement where the volume of the toner cartridge 11Y is reduced. The direction in which the toner near the toner outlet 11aY is scattered is reduced,
Further, the discharged toner hits the circumferential surface of the toner cartridge 11Y and is returned to the vicinity of the toner outlet 11aY, so that the amount of toner required for replenishment is secured near the upper portion of the outlet 11aY. Further, based on the detection result of the toner end sensor 12, instead of controlling the rotation speeds of the first toner transport screw 45 and the second toner transport screw 48, control is performed so as to change the volume of the toner hopper 46Y. May be configured. That is, when the toner end sensor 12 detects the toner near end, the signal is sent to the printer engine board, and the volume of the toner hopper 46Y is increased when the image forming process is executed thereafter. Specifically, as shown in FIG.
The position of the side wall of the toner hopper 46Y and the side wall of the toner cartridge 11Y in contact with the toner hopper 46Y can be moved in the direction of arrow I by a moving device (not shown) as a variable capacity means. The positions of the side movable wall 46cY of the toner hopper 46Y and the movable wall 11cY of the toner cartridge 11Y are shown in FIG.
It is moved from the position indicated by the solid line in FIG. 10A to the position indicated by the broken line in FIG. As a result, although the toner in the toner hopper 46Y has decreased at the position indicated by the solid line before the movement, the volume of the toner hopper 46Y has increased at the position indicated by the broken line after the movement. Is done. [0042] [0043] According to the present invention, according to the present invention, by the developer amount of the developer container to slow the image forming process speed in the case were Sukunaku' than a predetermined amount, the unit time Since the amount of developer consumed per unit is reduced, the amount of developer supplied to the developing device is smaller than usual, and the amount of developer supplied to the developer carrier of the developing device is also smaller than usual. However, there is an effect that a sufficient amount of the developer can be supplied onto the developer carrier. [0045]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view showing a schematic configuration of a full-color printer using a developing device according to an embodiment of the present invention. FIG. 2 is a front view of the inside of the developing device. FIG. 3 is a front view of the inside of one developing device of the developing device. FIGS. 4A to 4D are explanatory views showing the movement of toner in a yellow developing device when the developing device rotates. FIG. 5 is a perspective view of a developing device and a toner cartridge. FIGS. 6A to 6E are explanatory diagrams illustrating movement of toner in a yellow developing device when the developing device rotates in a toner near-end state. FIGS. 7A and 7B are explanatory diagrams of the inside of a yellow developing device in a normal state and a toner near-end state in a developing device according to a modification. FIGS. 8A and 8B are explanatory views of the inside of a yellow developing device in a normal state and a toner near-end state in a developing device according to another modification. FIGS. 9A and 9B are explanatory views of the inside of a yellow developing device in a normal state and a toner near-end state in a developing device according to still another modified example. FIGS. 10A and 10B are explanatory views of the inside of a yellow developing device in a normal state and a toner near-end state in a developing device according to still another modified example. DESCRIPTION OF SYMBOLS 1 Photoreceptor belt 4 Rotary developing device 11 Toner cartridge 11a Discharge port 11b Movable outer peripheral wall 11c Movable wall 12 Toner end sensor 41 Developing device 42 Developing roller 45 First toner transport screw 46 Toner hopper 46a Receiving port 46b Shutter Member 46c Movable wall 48 Second toner transport screw

────────────────────────────────────────────────── ─── Continued on the front page (72) Mayumi Miyao 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-7-114260 (JP, A) JP-A Heihei 1-166072 (JP, A) JP-A-6-308831 (JP, A) JP-A-7-84451 (JP, A) JP-A-6-130812 (JP, A) JP-A-61-95370 (JP, A) A) JP-A-61-117575 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/01-15/01 117 G03G 15/08-15/095 G03G 21/00 370

Claims (1)

(57) Patent Claims 1. A developing device in which a plurality of developing units are disposed for accommodating the powder developer around the rotating shaft, each of the developing devices to wear detachably attached to the rotates the developing unit integrally having <br/> a plurality of developer container containing a developer supplied to the developing device, the plurality of the developing device is rotated about the rotational axis Any of the developing devices is moved to a developing position where the developer carrying member of the developing device is opposed to the latent image carrier to perform development, and the developer container of the developer container is rotated with the rotation of the developing device. In an image forming apparatus in which developer is supplied from a discharge port to a receiving port of the developing device, a developer amount detecting unit that detects a developer amount in the developer container, and a detection result of the developer amount detecting unit. Based on image shape
An image forming apparatus comprising: a control unit for controlling a forming process speed .