JP2000098734A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the electric charge amount of developer, to suppress the lowering of image density or fogging when an image is formed after a device is stopped in a long term and to form the high-definition image by rotating a developer carrier at a higher speed than the normal speed of an image forming time in a prescribed time before the first image is formed when the image is formed after the device is stopped for a long term. SOLUTION: When it is judged that the image forming device is stopped in a long term, the developing sleeve 11 is rotated at the higher speed Vdhms than the normal speed Vdhmn of the image forming time by setting the rotating time Tdhms being as the prescribed time based on time Tdhma before the first image is formed. Then, it is good that the rotating speed Vdhms is set to be higher and the rotating time Tdhms is set to be longer as the time Tdhma is longer. Besides, developing bias is not applied in the time Tdhma and the potential of a covering member 18 is set to be identical to that of the sleeve 11. Thus, toner whose electric charge amount is insufficient is prevented from being splashed to the inside of the device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a developing means for developing a latent image formed on a latent image carrier with a developer.

[0002]

2. Description of the Related Art Conventionally, this type of image forming apparatus has an image (toner image) using a toner as a developer developed by a developing means 1 of an image forming section as shown in FIG.
Is transferred to the sheet, and is conveyed to the fixing means 6 so that the toner image is fixed on the sheet.

In the image forming section, a latent image is formed by a latent image forming means on a photosensitive drum 2 as a latent image carrier, and the latent image is developed by a developing means 1.

On the other hand, a toner image formed on the photosensitive drum 2 is transferred by a transfer means onto a sheet conveyed by a sheet conveyance means on a conveyance path on an upstream side of an image forming section. The sheet on which the unfixed toner image is formed is conveyed to a fixing unit 6 through a conveyance path on the downstream side of the image forming unit, where the toner image is fixed at a nip portion of a roller serving as a rotating body, and is externally provided. Is discharged.

FIG. 14 shows a schematic configuration of a developing means 1 using a toner as a one-component magnetic developer.

[0006] The developing means 1 includes a container 10 having an opening, and the container 10 contains toner. A developing sleeve 11 as a developer carrier is rotatably supported at the opening of the container 10. One half of the developing sleeve 11 enters the inside of the developing container 10, and the other half of the developing sleeve 11 It is exposed to the outside.

The developing sleeve 11 is made of a non-magnetic material such as an aluminum alloy or stainless steel, and is rotated at a predetermined peripheral speed in a counterclockwise direction A by a driving means (not shown).

A magnet roller 12 as a magnetic field generating means is fixedly installed concentrically inside the developing sleeve 11, and the peripheral surface of the magnet roller 12 is attached at predetermined intervals to form several magnetic poles. Magnetized.

Further, stirring and conveying members 13a, 13b and 13c for moving the toner so as to be swept in the direction of the developing sleeve 11 are disposed inside the container 10, and the stirring and conveying members 13a, 13b and 13c are not provided. It is rotationally driven at a predetermined speed by the driving means shown.

The photosensitive drum 2 is driven to rotate at a predetermined peripheral speed in a clockwise direction B in the figure, and an electrostatic latent image is formed on the surface by a latent image forming means (not shown) disposed around the photosensitive drum 2. When the photosensitive drum 2 and the developing sleeve 11 come closest to each other and face each other, the latent image
The toner carried thereon adheres to the photosensitive drum 2 to develop the latent image.

A developing bias is applied between the developing sleeve 11 and the photosensitive drum 2 from a power supply 19, and the developing bias generally superimposes a DC component on an AC component.

The toner contained in the container 10 is agitated by the agitating / conveying members 13a, 13b and 13c, and is rotated by the developing sleeve 11 and circulated by a magnetic field formed by the magnet roller 12 in the developing sleeve 11. Of the developing sleeve 11 due to rotation of the developing sleeve 11 and contact friction with the surface of the developing sleeve 11 due to rotation of the developing sleeve 11.

A part of the toner charged in this way is
The developing sleeve 11 is magnetically and electrically constrained and carried sequentially on the peripheral surface of the rotating developing sleeve 11, is further conveyed by the rotation of the developing sleeve 11, and is
It is in a state where a thin layer is coated thereon.

The toner coated in a thin layer on the developing sleeve 11 is transferred from the developing sleeve 11 to the photosensitive drum 2 when the photosensitive drum 2 and the developing sleeve 11 are most closely opposed by the rotation of the developing sleeve 11. 2 and develop the latent image. The toner not used for development is returned to the inside of the container 10 while being held on the developing sleeve 11.

When the toner inside the container 10 is consumed due to the development and the toner needs to be replenished, the toner is transferred from the toner cartridge 9 filled with about 2000 g of the toner on the front upper side of the image forming apparatus to the upper part of the container 10. Replenishment is carried out via a screw 17 from a supply port or the like that opens to the outside.

In the developing means 1 having the above-described structure, an image formed after the image forming apparatus has been stopped for a long period of time, such as at night, on a weekend, or on consecutive holidays, has low image density or fog over several tens to several hundred pages. Many cases were scattered. This is even more remarkable as compared with the output image immediately before the image forming apparatus is stopped for a long time.

In particular, the change in the image becomes worse (see FIGS. 15 and 16) as the mass We (g / kg) of water per kg of air (hereinafter referred to as the amount of environmental moisture) increases, and the image forming apparatus is stopped. The longer the period, the worse (see FIG. 17, FIG. 1)
8).

Such a phenomenon occurs because the charge amount of the toner decreases when the image forming apparatus is stopped for a long time, and it takes a long time to recover the charge amount after charging.

Therefore, after the image forming apparatus has been stopped for a long period of time, the developing sleeve 11 is turned on for several minutes during a standby time (a so-called standby state) for waiting for a rise in the temperature of the fixing means 6 and the like before image formation after the image forming apparatus is turned on. It has been practiced that the charge amount of the toner is increased by rotating the toner by a certain degree.

[0020]

However, when the developing sleeve 11 is rotated in the standby state according to the prior art described above, the charge amount of the toner is insufficiently increased, resulting in a low image density or fogging. Had many images.

When the developing sleeve 11 is rotated in a state where the charge amount of the toner is low, the developing sleeve 11 of the toner is rotated.
, It easily detached from the developing sleeve 11 and scattered, causing contamination inside the image forming apparatus.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object of the present invention is to suppress a decrease in image density and image fogging in image formation after the apparatus has been stopped for a long time, An object of the present invention is to provide an image forming apparatus which is capable of forming a high quality image and has excellent reliability.

[0023]

According to the present invention, there is provided an image forming apparatus comprising: a latent image carrier; and developing means having a rotating developer carrier for carrying a developer. In an image forming apparatus that forms an image by developing a latent image by attaching a developer from the developer carrier to a carrier, when image forming is performed after the apparatus is stopped for a long time, a predetermined time before the first image formation is performed. During this time, the developer carrier is rotated at a speed higher than the normal speed during image formation.

Therefore, the charge amount of the developer can be increased by the high-speed rotation of the developer carrying member, and a decrease in image density and fogging in image formation after the apparatus has been stopped for a long time can be suppressed.
High quality image formation becomes possible.

It is preferable that a cover member for covering the developer carrier is provided inside the container for storing the developer of the developing means for the predetermined time.

Thus, when the developer carrier is rotated at a high speed in order to increase the charge amount of the developer, the developer carrier is covered with the covering member, so that the developer is prevented from scattering inside the apparatus. can do.

It is preferable that a moving means for moving the developing means to a position farther from the latent image carrier than a normal position at the time of image formation during the predetermined time is provided.

Thus, the covering member can be easily guided between the latent image carrier and the developer carrier. Further, the coating operation of the developer carrier can be performed in conjunction with the movement of the developing unit by the moving unit.

A latent image carrier and developing means having a rotating developer carrier for carrying a developer, wherein a developing bias is applied between the developer carrier and the latent image carrier. In the image forming apparatus that forms an image by developing a latent image by causing the developer to fly and attaching the developer from the developer carrier to the latent image carrier, image formation is performed after the apparatus is stopped for a long time. In this case, the developing bias is applied at a frequency higher than a normal frequency to rotate the developer carrier during a predetermined time before the first image formation.

Therefore, the charge amount of the developer can be increased by the reciprocating movement of the developer between the developer carrier and the latent image carrier due to the high frequency developing bias, and the image after the apparatus has been stopped for a long period of time can be increased. A reduction in image density during formation and fogging are suppressed, and high-quality image formation can be performed.

There is provided an environmental moisture detecting means for detecting the environmental moisture content, and the rotation speed of the developer carrier or the developing bias frequency is set during the predetermined time according to the detection information of the environmental moisture content detecting means. Preferably, it is changed.

This makes it possible to easily set the charge of the developer without waste.

It is preferable to change the rotation speed of the developer carrier or the developing bias frequency during the predetermined time in accordance with the time during which the developer carrier has stopped rotating for a long time.

This makes it possible to easily set the charge of the developer to be increased without waste.

A fixing device having a rotating body and a surface temperature detecting means for detecting a surface temperature of the rotating body is provided. When the temperature detected by the surface temperature detecting means becomes lower than a predetermined temperature, the apparatus is stopped for a long time. It is preferable to determine that it has been done.

This eliminates the need for extra members.

[0037]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The material, shape, relative arrangement, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

(First Embodiment) An image forming apparatus according to a first embodiment is similar to the prior art shown in FIG.
Therefore, the same reference numerals are given here and the description is omitted.

A developing device according to the first embodiment is shown in FIG.
As shown in FIG. 1 and 2, a developing means 1 includes a resin container 10 for accommodating a toner and a non-magnetic metal developing sleeve 11 (diameter 24.
5 mm), a resin stirring and conveying member 13b made of resin, toner stirring and conveying members 13a and 13c made of non-magnetic metal, and a blade 14 made of non-magnetic metal.

The container 10 has a maximum depth of 310 mm and a maximum height of 4
It has a toner storage space with a maximum width of 5 mm and a width of about 80 mm.
It has two toner stirring areas 10a, 10b, 10c.

The container 10 has an opening, and approximately half the circumference of the developing sleeve 11 is arranged inside the container, and approximately half the circumference is exposed to the outside. The developing sleeve 11 is a developing sleeve 1
1 includes a magnet roller 12 having six magnetic poles, and attracts magnetic toner by the magnetic force of a magnet;
The toner carried on the developing sleeve 11 is
In step 4, the toner amount is regulated to form a thin layer.

The blade 14 is formed in a plate shape having a thickness of 0.8 mm, and the gap between the blade 14 and the developing sleeve 11 is 210 to 270.
um.

The thin layer toner on the surface of the developing sleeve 11 provided by the blade 14
Is rotated to a gap (150 to 270 u) with the developing sleeve 11.
m), the electrostatic latent image is developed by adhering to the photosensitive drum 2 which has come close to and faced.

Here, during image formation, the developing sleeve 1
1 is rotationally driven in the direction A at a speed Vdhmn (550 mm / s).

The power supply 19 supplies an amplitude Vppdev (= 1300) between the developing sleeve 11 and the photosensitive drum 2.
V), a developing bias in which a DC voltage Vdcdev of 150 to 300 V is superimposed on a saw-shaped AC voltage having a frequency fdevn (= 2700 Hz).

The photosensitive drum 2 has a diameter of 80 in which a photosensitive layer mainly composed of amorphous silicon is formed on an aluminum alloy base material.
mm in a hollow cylinder and rotates in the B direction at a speed of 265 mm / s.

In the vicinity of the developing sleeve 11, the developing sleeve 11 is rotatably supported coaxially with the rotation axis of the developing sleeve 11. The developing sleeve 11 has a partial cylindrical shape and can cover the developing sleeve 11 inside the container 10. A covering member 18 is provided. The covering member 18 is made of a non-magnetic metal (1.0 mm thick) having an inner surface with a radius of curvature of 15 mm.

The developing means 1 is moved by the moving means 72.
It is possible to move away from the photosensitive drum 2.

As shown in FIG. 3, the covering member 18 has teeth 18a on a part thereof and meshes with gears 73 and 74 provided on the image forming apparatus side. The covering member 18 can be moved in the J1 and J2 directions in conjunction with the movement of the moving means 72 in the F1 and F2 directions.

At the time of image formation, that is, while the developing means 1 supplies toner to the photosensitive drum 2 via spacer rollers (not shown), as shown in FIG. The toner can be supplied to the photosensitive drum 2 from the developing sleeve 11 which is retracted to the side and exposed from the opening.

Next, the operation before image formation after the image forming apparatus of the present embodiment has been stopped for a long time will be described.

Here, the determination that the image forming apparatus has been stopped for a long period of time is determined by the main control unit by recognizing the time Tlife at which the image formation was last performed by a timing unit (not shown), and storing it in the main control unit. Is calculated by calculating a time Tdhma that is a difference from the image formation start time Tpif.

When it is determined that the image forming apparatus has been stopped for a long period of time, as shown in FIG. 5, before the first image formation, the developing sleeve 11 is moved from the normal speed Vdhmn during image formation based on the time Tdhma. Fast rotation speed Vd
hms and a rotation time Tdhms as a predetermined time are set and rotated. The criterion corresponding to FIG. 5 is stored in the main control unit.

Here, the longer the time Tdhma, the faster the rotation speed Vdhms and the longer the rotation time Tdhms.

At this time, the developing means 10 is separated from the photosensitive drum 2 by the moving means 72 as shown in FIG.
While the developing means 1 is separated from the photosensitive drum 2 in accordance with the operation of the moving means 72, the covering member 18 comes to a position covering the developing sleeve 11 and closes the opening.

During the time Tdhma, the developing bias is not applied or remains at the time of image formation.
The covering member 18 is set to the same potential as the developing sleeve 11.

As a result, even when the developing sleeve 11 is rotated at a high speed, the toner having an insufficient charge amount is prevented from scattering into the apparatus.

Further, an environmental sensor 52 is provided as environmental moisture detecting means. The environmental moisture We, which is the amount of moisture per kg of air detected by the environmental sensor 52, is used when setting the rotation speed Vdhms and the rotation time Tdhms. As shown in FIG. 5, the larger the environmental moisture amount We, the faster the rotation speed Vdhms and the longer the rotation time Tdhms.

As shown in FIG. 4, the environment sensor 52 is disposed on the operation plate 51 on the upper front side of the image forming apparatus.

In this embodiment, as described above, before the first image formation after the image forming apparatus has been stopped for a long time, the developing sleeve 11 is rotated at the rotation speed Vdh for the rotation time Tdhms.
6 and 7, the amount of charge of the toner can be increased, and as shown in FIGS. 6 and 7, compared with the prior art, a reduction in image density of a formed image and suppression of fogging can provide high quality. Image can be obtained.

(Second Embodiment) A second embodiment of the present invention will be described. Here, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In this embodiment, the developing sleeve 11 is not provided with the covering member 18 and is rotated at the same speed as the rotation speed Vdhmn during the normal image formation before the first image formation after the image forming apparatus has been stopped for a long time. Then, a developing bias having a higher frequency than that during normal image formation is applied and the image is rotated.

In the present embodiment, when it is determined that the image forming apparatus has been stopped for a long period of time, as in the first embodiment, the developing sleeve 11 is set to the time Td before the first image formation.
Based on hma, as shown in FIG. 8, the developing bias frequency fdevs, the normal speed Vdhmn during image formation
Faster rotation speed Vdhms and rotation time Tdhhm
Determine and rotate s.

In this embodiment, since the coating member 18 and the moving means 72 are not provided, the developing bias is applied while the developing sleeve 11 before image formation after the image forming apparatus is stopped for a long time is rotating. Then, the toner reciprocates between the photosensitive drum 2 and the developing sleeve 11, and the toner collides with the photosensitive drum 2 and the developing sleeve 11 to increase the charge amount of the toner.

Here, the frequency fdevs of the applied developing bias is higher than the frequency at the time of image formation in order to further increase the number of reciprocating movements and to further increase the charging of the toner. The longer the time Tdhma, the higher the development bias frequency fdevs, and the longer the rotation time Tdhma.
dhms should be lengthened.

Further, the environmental moisture amount We detected by the environmental sensor 52 is also considered when determining the developing bias frequency fdevs and the rotation time Tdhms, and the environmental moisture amount We is determined.
Is larger, the developing bias frequency fdevs is higher, and the rotation time Tdhms is longer.

Also in this case, similarly to the first embodiment, the charge amount of the toner can be increased, and a high-quality image can be formed by suppressing a decrease in image density of a formed image and fogging. Obtainable.

The developing sleeve 11 may be rotated at a rotational speed Vdhms that is not the same as the rotational speed Vdhmn during normal image formation but is higher than the normal speed Vdhmn as in the first embodiment. .

(Third Embodiment) A third embodiment according to the present invention will be described. In the present embodiment, the time Tdhma is not calculated, and the time Tdhma by the timer is not used to determine that the image forming apparatus has been stopped for a long time. Other similar configurations are denoted by the same reference numerals as in the first and second embodiments, and description thereof will be omitted.

First, the known fixing means 6 in the image forming apparatus will be described in detail.

As shown in FIG. 9, the fixing means 6 has a known structure having rollers 61 and 62 serving as two upper and lower rotating members sandwiching a sheet.

The upper roller 61 on the toner image side has a center layer 61a made of an aluminum alloy having an outer diameter of 50 mm and an inner diameter of 28 mm.
Is covered with a material 61b mainly composed of silicon rubber having a thickness of 0.3 mm, and further, the periphery thereof is covered with PTFE.
Is provided.

The surface temperature of the roller 61 is detected by a thermistor 63 as a surface temperature detecting means, and is controlled at 175 ° C. by a control means (not shown).

The thermistor 63 is located 54 mm deep from the center of the roller 61 in the longitudinal direction, and has an amplitude of 1 around that point.
It reciprocates in the K direction every 2 mm at a period of 44 to 136 pages (see FIG. 10).

The lower roller 62 on the side opposite to the toner image surface has a diameter of 50 mm and a center portion 62a made of aluminum alloy.
Is a material 6 mainly composed of a fluorine compound having a thickness of 100 μm.
2b.

Both rollers 61 and 62 are 980-1200 N
Contact, and as a result, a width of 6.8 to
A 7.8 mm nip is formed, and both are driven to rotate at an outer peripheral speed of 265 mm / s.

Further, five claw-like sheet peeling means 64 in the longitudinal direction and a film-like cleaning member 65 are in contact with the roller 61 over the entire area in the longitudinal direction.

The cleaning member 65 is a non-woven fabric impregnated with silicon oil or the like, and is gradually taken up by the take-up means 65a as the image formation progresses.
1. Clean the toner, dust, etc. attached to the surface.

In this embodiment, it is determined that the image forming apparatus has been stopped for a long time by pressing the image forming start button of the image forming apparatus or by performing image forming from a terminal device such as a personal computer connected to the image forming apparatus. Immediately after receiving the start, the fixing roller 61 detected by the thermistor 62
Between the surface temperature Tf (° C.) and the external temperature Te (° C.) detected by an external sensor (not shown), Tf <min (Te + 5)
5, 75), it is determined that the image forming apparatus has been stopped for a long time.

Here, the predetermined temperature min (Te + 5
5,75) means the smaller one of Te + 55 ° C and 75 ° C.

As described above, when it is determined that the image forming apparatus has been stopped for a long time, the developing sleeve 11 is shown in FIG. 11 based on the environmental moisture amount We detected by the environmental sensor 52 before the first image formation. Thus, the developing bias frequency fdevs, the rotation speed Vdhms, and the rotation time Tdh
Determine ms and rotate.

In the same manner as in the first and second embodiments, the environmental moisture amount We detected by the environmental sensor 52 is changed by the developing bias frequency fdevs, the rotation speed Vdhms, and the rotation time Td.
hms, etc., may be taken into consideration, but the environment sensor 52 is not provided, and the environmental moisture amount We is not taken into account.
An image forming apparatus that is superior to the apparatus including the environment sensor 52 in terms of apparatus manufacturing cost may be realized.

FIG. 12 is a comparison of the above-described embodiments with the prior art. Referring to FIG. 12, the image reflection density is reduced by copying a circular original having a diameter of 5 mm and a reflection density of 1.1. This is an average value obtained by measuring the transmission densities at five points on the same-size image using a transmission densitometer.

The increase in fog reflectance is obtained by subtracting the reflectance of a solid white image after toner replenishment from the reflectance measured using a densitometer on the solid white image before toner replenishment.

The device cost is a relative cost with respect to the prior art. Further, the third embodiment A is provided with an environment sensor 52 in which the environmental moisture amount We is taken into consideration in the third embodiment, and the third embodiment B is provided with the environment sensor in the third embodiment. The environmental sensor 52 does not consider the water content We.
It does not have.

Although the embodiments of the present invention using a magnetic one-component toner have been described above, the present invention is not limited to these embodiments. Can be applied to the image forming apparatus.

In the case of a two-component toner, the detection of the toner amount means the ratio of the toner to the carrier particles, that is, the toner concentration.

The image forming apparatus to which the present invention can be applied includes a monochrome digital copying machine, a full-color copying machine, a printer, a facsimile, and a so-called multi-function image forming apparatus integrating these functions.

Further, a developing means having two or more developing sleeves 11, a developing means in which the developing sleeve 11 contacts the photosensitive drum 2, and a developing means in which the developing sleeve 11 and a magnet roller included in the developing sleeve 11 rotate together An image forming apparatus having means and the like may be used.

In other words, of course, all changes that are considered small changes in the spirit of the present invention are included in the scope of the concept of the present invention.

[0091]

As described above, according to the present invention, when image formation is performed after the apparatus has been stopped for a long time, the developer carrier is kept at a lower speed than the normal speed during image formation for a predetermined time before the first image formation. Also, by rotating the developer carrier at a high speed, the charge amount of the developer can be increased by the high-speed rotation of the developer carrying member. Image formation becomes possible.

For a predetermined period of time, the covering means for covering the developer carrier is provided inside the container for housing the developer of the developing means, so that the developer carrier is moved at a high speed in order to increase the charge amount of the developer. When rotated, the developer carrier is covered with the covering member, so that the developer can be prevented from scattering into the inside of the device.

By providing moving means for moving the developing means to a position more distant from the latent image carrier than the normal position during image formation for a predetermined time, the covering member can be moved to the latent image carrier and the developer carrier. Can be easily guided during. Further, the coating operation of the developer carrier can be performed in conjunction with the movement of the developing unit by the moving unit.

When an image is formed after the apparatus has been stopped for a long period of time, a developing bias is applied to the developer carrier at a frequency higher than the normal frequency for a predetermined time before the first image formation, and the developer carrier is moved. By rotating the developer, the charge amount of the developer can be increased by increasing the reciprocating motion between the developer carrier and the latent image carrier due to a high frequency developing bias, and the image after the apparatus has been stopped for a long period of time. A reduction in image density during formation and fogging are suppressed, and high-quality image formation can be performed.

An environmental moisture detecting means for detecting the environmental moisture is provided, and the rotation speed of the developer carrier or the developing bias frequency is changed for a predetermined time in accordance with the detection information of the environmental moisture detecting means. In addition, the setting for increasing the charge of the developer can be easily performed without waste.

By changing the rotation speed of the developer carrier or the developing bias frequency for a predetermined time in accordance with the time during which the developer carrier has stopped rotating for a long time, the charge of the developer can be efficiently used. It can be easily set to raise.

A fixing device having a rotating body and a surface temperature detecting means for detecting the surface temperature of the rotating body is provided. When the temperature detected by the surface temperature detecting means becomes lower than a predetermined temperature,
By judging that the apparatus has been stopped for a long time, no extra member is required, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a state in which a developing unit according to a first embodiment is capable of developing.

FIG. 2 is a cross-sectional view illustrating a state in which a developing unit according to the first embodiment is separated from a photosensitive drum.

FIG. 3 is a configuration diagram illustrating a driving mechanism of a covering member and a moving unit according to the first embodiment.

FIG. 4 is a model diagram showing a part of an upper portion of the image forming apparatus.

FIG. 5 is a table for setting an operation of a developing unit before image formation after the image forming apparatus according to the first embodiment has been stopped for a long time.

FIG. 6 is a graph showing a change in image density of an image formed before and after a long term stop in the first embodiment and the related art.

FIG. 7 is a graph showing a reduction in fog reflectance of an image formed before and after a long term stoppage in the first embodiment and the related art.

FIG. 8 is a table for setting operations of a developing unit before image formation after the image forming apparatus according to the second embodiment has been stopped for a long time.

FIG. 9 is a cross-sectional view illustrating a fixing unit used in the image forming apparatus.

FIG. 10 is a side view illustrating a fixing unit used in the image forming apparatus.

FIG. 11 is a table for setting the operation of the developing unit before image formation after the image forming apparatus according to the third embodiment has been stopped for a long time.

FIG. 12 is a table showing a comparison between the embodiment and the prior art.

FIG. 13 is a cross-sectional view illustrating a main part of the image forming apparatus.

FIG. 14 is a cross-sectional view showing a conventional developing means.

FIG. 15 is a graph showing the influence of the amount of environmental moisture on the transition of the image density of an image formed before and after a long term stoppage in the related art.

FIG. 16 is a graph showing the influence of the amount of environmental moisture on the change in the fog reflectance of an image formed before and after a long term stoppage in the related art.

FIG. 17 is a graph showing the influence of the long-term suspension period of the image forming apparatus on the transition of the image density of the image formed before and after the long-term suspension in the related art.

FIG. 18 is a graph showing the influence of the long-term suspension period of the image forming apparatus on the change in the fog reflectance of the image formed before and after the long-term suspension in the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Developing means 2 Photosensitive drum 6 Fixing means 9 Toner cartridge 10 Container 11 Developing sleeve 12 Magnet roller 13 Toner stirring and conveying member 14 Blade 17 Screw 18 Coating member 18a Teeth 19 Power supply 51 Operating part 52 Environmental sensor 61, 62 Roller 63 Thermistor 64 Sheet Peeling means 65 Cleaning member 72 Moving means 73, 74 Gear

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H027 DA13 DA14 DA38 DA40 DA50 DE07 EA05 ED02 ED08 EE03 2H073 BA04 BA21 BA22 BA33 CA02 2H077 AD36 DA01 DA18 DB08 EA13 EA16 9A001 BB04 JJ35 KK15 KK37 KK42 LL02

Claims (7)

[Claims] 1. A latent image carrier, and developing means having a rotating developer carrier that carries and rotates a developer, wherein a developer is attached to the latent image carrier from the developer carrier. In an image forming apparatus that develops a latent image to form an image, when the image is formed after the apparatus has been stopped for a long period of time, the developer carrier is rotated at a normal speed during a predetermined time before the first image formation. An image forming apparatus characterized in that the image forming apparatus is rotated faster. 2. The image forming apparatus according to claim 1, further comprising: a cover member that covers the developer carrier on the inner side of the container that stores the developer of the developing unit during the predetermined time. . 3. The image forming apparatus according to claim 2, further comprising a moving unit that moves the developing unit to a position farther from the latent image carrier than a normal position during image formation during the predetermined time. Image forming apparatus. 4. A developing device comprising: a latent image carrier; and developing means having a rotating developer carrier for carrying a developer, wherein a developing bias is applied between the developer carrier and the latent image carrier. An image forming apparatus for developing a latent image by applying a developer to the latent image carrier and applying a developer from the developer carrier to form a latent image; Wherein the developing bias is applied at a frequency higher than a normal frequency to rotate the developer carrier for a predetermined time before the first image formation. 5. An image forming apparatus according to claim 1, further comprising: an environmental moisture detecting unit configured to detect an environmental moisture amount, wherein the developer carrier rotation speed or the developing bias is maintained for the predetermined time according to detection information of the environmental moisture detecting unit. 3. The method according to claim 1, wherein the frequency is changed.
5. The image forming apparatus according to 3 or 4. 6. The developer carrier rotation speed or the developing bias frequency is changed during the predetermined time in accordance with a time during which the developer carrier has stopped rotating for a long time. The image forming apparatus according to claim 1, 2, 3, or 4, wherein: 7. A fixing device comprising: a rotating body; and a surface temperature detecting means for detecting a surface temperature of the rotating body. When the temperature detected by the surface temperature detecting means becomes lower than a predetermined temperature, the apparatus is activated. The image forming apparatus according to claim 1, wherein it is determined that the image forming apparatus has been stopped for a long time.