JPH08160812A - Image forming device - Google Patents

Abstract

PURPOSE: To provide an image forming device capable of stably obtaining images without fogging or stains by effectively cleaning a photosensitive body after the production of jamming even when a noncontact developing system or a simple cleaning system having no cleaning canisters is employed. CONSTITUTION: An image forming device is provided with a photosensitive body 1, a charging roller (charger) 2, a developing device 3 with at least toner (developing agent) in noncontact with the photosensitive body, transfer roller (contact transfer device) 5 and a cleaning roller (simple cleaning means) 6 for temporarily collecting transfer remaining toner on the photosensitive body 1. The device is further provided with a means for detecting the production of jamming, a nonvolatile memory for storing the production of jamming and a means for detecting the production of jamming and transmitting this to the nonvolatile memory and where jamming production occurs in the nonvolatile memory when a power is input to the main body, a photosensitive cleaning sequence is executed ahead of a normal sequence and after photosensitive body cleaning sequence is finished, the nonvolatile memory is reset and processing returns to the normal sequence.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called cleanerless image forming apparatus such as a laser printer or a copying machine using an electrophotographic system.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic system, the surface of a photoconductor, which is an image carrier, is charged by a charging device, and then the surface of the photoconductor is irradiated with light to electrostatically charge the photoconductor. A latent image is formed, and the electrostatic latent image is developed with toner supplied from a developing device to visualize it as a toner image. This toner image can be transferred from a photoconductor to a transfer sheet by a transfer unit. Done. The transfer residual toner remaining on the photoconductor after the transfer is removed by a cleaning device,
The photoconductor is again subjected to the charging process by the charging device. Then, the transfer paper onto which the toner image has been transferred is output from the image forming apparatus after the toner image is fixed by the fixing device.

The cleaning process in the above series of image forming processes is important and essential.

That is, it is difficult to transfer 100% of the toner used for development to the transfer paper in the transfer step, and the following step is performed unless the cleaning step, which is a step of removing the transfer residual toner from the photosensitive member, is performed. Uniform charging or exposure is not performed in the charging process or the exposure process, and the image quality is degraded.

By the way, as a conventional cleaning method, a method in which a fur brush, a rubber blade or the like is brought into contact with the photosensitive member to scrape off the transfer residual toner is generally used. Then, the transfer residual toner scraped off is scooped by a scooping sheet or the like and accumulated as waste toner in the cleaner container.

On the other hand, some cleanerless (more precisely, cleaner containerless) image forming methods have been proposed.

That is, in the cleanerless image forming method, instead of actively scraping the toner by the cleaner member and collecting and accumulating the toner in the container, only the auxiliary cleaning means such as a brush and a roller is provided and the transfer residue is left. This is a method of temporarily storing the toner or dispersing the toner so as not to disturb the latent image, and finally collecting and reusing the transfer residual toner in a developing device.

According to this method, since the space of the cleaner container is unnecessary, not only the apparatus can be downsized and simplified, but also the transfer residual toner can be collected by the developing device without producing the waste toner. This is advantageous from an ecological point of view and running cost.

A typical cleanerless image forming method will be described below.

First, an example in which a cleaning roller is used as an auxiliary cleaning means will be described.

The cleaning roller is made of an elastic material,
This is rotatably in contact with at least an area of the image forming width of the photosensitive member, and DC is applied to the cleaning roller during image forming.
A bias is applied to form a potential difference between the cleaning roller and the surface of the photoconductor, and transfer residual toner on the photoconductor is transferred and held on the cleaning roller.

Further, at the time of non-image formation before and after image formation, a DC bias is applied to the cleaning roller so that a potential difference that transfers the toner on the cleaning roller to the photosensitive member is formed, and the toner on the cleaning roller is removed. Clean the cleaning roller by transferring it onto the photoconductor.

Thus, the toner transferred from the cleaning roller onto the photosensitive member forms a potential difference that transfers the toner to the developing device, so that the toner is finally collected by the developing device and used again for development. It

Next, an example in which a memory removing brush is used as an auxiliary cleaning means will be described.

According to this method, a DC bias is applied to the memory removal brush to form a potential difference between the brush and the surface of the photoconductor, and transfer residual toner on the photoconductor is transferred and held on the memory removal brush. Is. The toner stays on the memory removal brush until the toner retention capacity of the memory removal brush reaches the limit value.

When the amount of toner transferred to the memory removing brush exceeds the maximum toner holding amount, the memory removing brush can no longer hold the excess toner, and therefore the memory removing brush again puts the toner on the photosensitive member. Will be blown out to. In this way, the memory removal brush disperses the transfer residual toner while utilizing the overflow effect of the toner, and moves to the next step.

The toner blown from the memory removing brush onto the photosensitive member forms a potential difference that transfers the toner to the developing device, and is finally collected by the developing device and used again for development. It

[0018]

By the way, in the above-mentioned cleanerless image forming method, the toner must be collected in the developing device by electrostatic force. For this reason, the developer on the developing sleeve, which is the toner carrier of the developing device, or the developing sleeve needs to come into contact with the photoconductor, and sufficient electrostatic force must be applied to the toner on the photoconductor by the contact. The toner on the photoconductor can be collected in the developer or on the developing sleeve.
This is common to both cases where a memory removal brush and a cleaning roller are used as auxiliary cleaning means, and contact development is essential in the cleanerless image forming method.

However, when the toner and the developing sleeve are in contact with the photosensitive member, the photosensitive member and the toner are deteriorated at the contact portion or the developing sleeve is deformed when left standing for a long time.
Therefore, there is a problem that density unevenness and white background fogging occur in the image.

Further, since the developer comes into contact with the photosensitive member, if the tribo of the toner is not proper, the toner adheres to the image as fog, and fog is likely to occur.

The present invention has been made in view of the above problems, and an object thereof is to clean a photosensitive member after a jam even if a non-contact developing method and a simple cleaning method without a cleaning container are adopted. It is an object of the present invention to provide an image forming apparatus capable of effectively performing the above and stably obtaining an image free from fogging and stains.

[0022]

To achieve the above object, the invention according to claim 1 provides a photoconductor, a charging device, a developing device in which at least a developer is not in contact with the photoconductor, and a contact transfer. An image forming apparatus having an apparatus and a simple cleaning means for temporarily collecting the transfer residual toner on the photoconductor or a memory removing means for disturbing the transfer residual toner, and means for detecting occurrence of a jam, When a non-volatile memory for storing the occurrence of a jam and a means for detecting the occurrence of the jam and transmitting the jam to the non-volatile memory are provided, and the non-volatile memory stores the jam occurrence when the main body is powered on. To execute the photoconductor cleaning sequence in preference to the normal sequence, and reset the nonvolatile memory to return to the normal sequence after the photoconductor cleaning sequence is completed. The cleaning sequence is performed by supplying one transfer sheet as a photoconductor cleaning sheet to the transfer area and transferring the residual toner remaining on the photoconductor in the transfer area to the cleaning sheet. It is characterized in that the sequence is such that the paper is output to the outside of the apparatus.

According to a second aspect of the present invention, in the first aspect of the present invention, the photosensitive member cleaning sequence is performed by supplying one transfer sheet as a photosensitive member cleaning sheet to a transfer area and transferring the residual toner on the photosensitive member. Is held in the contact transfer device, and after the transfer residual toner held in the contact transfer device in the transfer area is transferred to the cleaning paper, the cleaning paper is output to the outside of the device.

According to a third aspect of the present invention, in the first aspect of the present invention, the photosensitive member cleaning sequence is performed by supplying one transfer sheet as a photosensitive member cleaning sheet to a transfer area and transferring residual toner on the photosensitive member. Is held on the photoconductor and the contact transfer device, the transfer residual toner held on the photoconductor in the transfer area is transferred to the cleaning paper surface, and the transfer residual toner on the contact transfer device is transferred to the back surface of the cleaning paper. It is characterized in that the cleaning sheet is output to the outside of the apparatus later.

According to a fourth aspect of the present invention, in the first, second or third aspect of the invention, the contact transfer device is a transfer roller.

According to a fifth aspect of the present invention, a photoconductor, a charging device, a developing device in which at least a developer is not in contact with the photoconductor, a contact transfer device, cleaning means for the contact transfer device, and In an image forming apparatus having a simple cleaning means for temporarily collecting transfer residual toner on a photoconductor or a memory removing means for disturbing the transfer residual toner,
A unit for detecting the occurrence of a jam, a non-volatile memory for storing the occurrence of the jam, and a unit for detecting the occurrence of the jam and transmitting it to the non-volatile memory are provided, and the non-volatile memory is provided when the main body is powered on. If the occurrence of a jam is stored in, the photoconductor cleaning sequence is executed with priority over the normal sequence, and after the photoconductor cleaning sequence is completed, the nonvolatile memory is reset to return to the normal sequence. In the photosensitive member cleaning sequence, the transfer residual toner held on the photosensitive member is transferred to the contact transfer device, and the cleaning means of the contact transfer device is operated to recover the transfer residual toner on the contact transfer device. In a sequence, the cleaning means of the contact transfer device is deactivated at least during image formation in a normal sequence. That.

According to a sixth aspect of the present invention, the photoconductor, the charging device, the developing device in which at least the developer is not in contact with the photoconductor, the transfer device, and the transfer residual toner on the photoconductor are temporarily stored. In an image forming apparatus having a simple cleaning unit that collects on a sheet or a memory removing unit that disturbs the transfer residual toner, a unit that detects the occurrence of a jam, a non-volatile memory that stores the occurrence of the jam, and a occurrence of the jam And means for transmitting it to the non-volatile memory,
If a jam is stored in the non-volatile memory when the power of the main unit is turned on, the photoconductor cleaning sequence is executed with priority over the normal sequence, and the non-volatile memory is reset after the photoconductor cleaning sequence is completed. Then, returning to the normal sequence, at least a part of the developer in the developing device is brought into contact with the photoconductor during the photoconductor cleaning sequence.

According to a seventh aspect of the invention, in the invention according to the sixth aspect, the developing device is fixed to a developer carrier rotatably supported and fixed inside the developer carrier during a normal sequence. The magnetic field generating means is fixed in such a manner that the magnetic field generating means is moved and fixed in a direction opposite to the rotation direction of the developer carrying member at the start of the photoconductor cleaning sequence, and the magnetic field generating means is fixed at the end of the photoconductor cleaning sequence. It is characterized in that the fixed magnetic field generating means is returned to the original position again and fixed.

According to an eighth aspect of the invention, in the invention according to the sixth aspect, the developing device is rotatably supported by a developer carrier, and magnetic field generating means fixed inside the developer carrier. And the developer carrier is rotated in a direction opposite to that in the normal sequence during the photosensitive member cleaning sequence.

According to a ninth aspect of the present invention, in the invention according to the sixth aspect, the developing device is rotatably supported by a developer carrier rotatably supported therein. A magnetic field generating means is included, and the number of rotations and the direction of rotation of the developer carrier and the magnetic field generating means are changed with respect to those in the normal sequence during the photoconductor cleaning sequence.

According to a tenth aspect of the invention, in the invention according to the sixth aspect, the developing device is rotatably supported by a developer carrier, and magnetic field generating means fixed inside the developer carrier. And a developer regulating means disposed outside the developer carrier with a gap between the developer carrier surface and the developer carrier surface, and the developer carrier during the photoconductor cleaning sequence. The gap between the body and the developer regulating means is made larger than that in the normal sequence.

According to an eleventh aspect of the present invention, in the invention according to the sixth aspect, the developing device is rotatably supported by a developer carrier, and magnetic field generating means fixed inside the developer carrier. And a developer regulating means that is in contact with the surface of the developer bearing member at a predetermined pressure outside the developer bearing member. It is characterized by making it smaller than that.

According to a twelfth aspect of the present invention, in the invention according to the sixth aspect, the developing device is a rotatable developer disposed facing the photoconductor with a gap provided between the developing device and the photoconductor. A carrier is included, and the gap is made smaller during the photoconductor cleaning sequence than during the normal sequence.

[0034]

According to the present invention, when it is confirmed that a jam has occurred when the power of the main body is turned on, the photoconductor cleaning sequence is executed with priority over the normal sequence, and in the photoconductor cleaning sequence, One piece of transfer paper is supplied to the transfer area as a photoconductor cleaning paper, and the transfer residual toner held on the photoconductor in the transfer area is transferred to the cleaning paper, and then the cleaning paper is output to the outside of the apparatus. Therefore, even in an image forming apparatus that employs a non-contact developing method and a simple cleaning method that does not have a cleaning container, the photoconductor can be effectively cleaned after a jam occurs, and an image free from fogging and dirt can be stably obtained. be able to.

[0035]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

<First Embodiment> FIG. 1 is a sectional view of a laser beam printer which is an image forming apparatus according to the first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a photoconductor, and the photoconductor 1 is constituted by forming a photosensitive layer 1a on a cylindrical grounded conductive substrate 1b, and the photoconductor 1 is provided at an end portion thereof. A gear and the like for receiving rotational drive of 1 are fixed. Reference numeral 2 denotes a charging roller as a contact charging member, which contacts the photoconductor 1 to charge the surface of the photoconductor 1 to a predetermined potential. A developing device 3 has a developing sleeve 4 parallel to the photoconductor 1, and neither the developing sleeve 4 nor the toner on the developing sleeve 4 is in contact with the photoconductor 1. Reference numeral 5 is a transfer roller which is a transfer means, and 6 is a cleaning roller which is a photoreceptor simple cleaning means.

By the way, the charging roller 2 includes the metal shaft 2
a and 10 ⁵ to 10 ⁶ Ω covered with a roller around the periphery
The metal shaft 2a is rotatably supported by bearings (not shown), and the charging roller 2 is always in contact with the photoconductor 1.
The metal shaft 2a is electrically connected to a charging bias applying power source 15, and a bias is applied to the charging roller 2 through the metal shaft 2a to charge the surface of the photoconductor 1 to a predetermined potential. To do.

During image formation, the photosensitive member 1 is rotationally driven in the direction of arrow A in FIG. 1 at a predetermined peripheral speed (process speed) based on the image formation start signal. The charging roller 2 is driven to rotate as the photosensitive member 1 is driven to rotate, and DC-1300V is applied to the charging roller 2 as a charging bias. The charging roller 2 charges the surface of the photosensitive member 1 to about -750V. To be done.

Next, the charged surface of the photoconductor 1 is exposed with image information by the laser beam 11 which is the exposing means output from the exposing means 10 of the apparatus main body,
The surface potential of the exposed portion of the photoconductor 1 decreases to about −150 V, so that an electrostatic latent image corresponding to the exposed image is sequentially formed on the surface of the photoconductor 1.

Then, the electrostatic latent image formed on the photoconductor 1 is successively developed as a toner image by the developing device 3. The developing device 3 uses a non-contact developing method, and the developing device 3 includes the rotating developing sleeve 4
A developing container 12 for supporting the developing sleeve 4 and containing the magnetic toner 9, a magnet roll 7 in the developing sleeve 4, and a D blade 8 for regulating the amount of toner on the developing sleeve 4. The developing sleeve 4 is electrically connected to the developing bias applying power source 16, and
And are arranged in parallel with each other through a predetermined gap. The magnetic toner 9 is held on the developing sleeve 4 by the magnetic force of the magnet roll 7, and is charged to a predetermined polarity (negative in this embodiment) by frictional charging with the surface of the developing sleeve 4.

At the time of image formation, the developing sleeve 4 is rotationally driven in the direction of arrow H in FIG. 1, and the toner 9 held on the developing sleeve 4 is conveyed to the vicinity of the photoconductor 1. Photoconductor 1
The toner 9 on the developing sleeve 4 which is conveyed to the vicinity of is regulated to a predetermined thickness by the D blade 8.

The developing sleeve 4 is applied with a predetermined superimposed DC voltage and AC voltage as a developing bias. In this embodiment, the developing bias is 1300 Vp.
By applying an AC bias of p, 2000 Hz and DC-400V, the toner 9 is applied to the exposed portion of the photoconductor 1.
Is attached to visualize the electrostatic latent image as a toner image.

Next, the transfer sheet P and the toner image on the photosensitive member 1 are synchronously pressed between the transfer roller 5 pressed against the photosensitive member 1 and the photosensitive member 1, and the transfer bias power supply 13 is used. A transfer bias is applied and the toner image is transferred from the photoconductor 1 to the transfer paper P. The transfer roller 5
Is 10 ⁷ to 10 ¹⁰ Ω · c on the outer circumference of the conductive metal shaft 5a.
An elastic body 5b having a resistance value of about m is formed in a cylindrical shape and is in contact with the photoconductor 1 with a predetermined contact pressure. The transfer roller 5 is supported similarly to the charging roller 2, and a transfer bias is applied to this.

During image transfer, a transfer bias of about +1 KV is applied to the transfer roller 5, most of the toner image is transferred to the transfer paper P, and the untransferred residual toner on the photosensitive member 1 is transferred. Few.

Then, a very small amount of residual toner on the photosensitive member 1 is collected by the cleaning roller 6. The cleaning roller 6 is constantly rotatably pressed against the photoconductor 1 and rotates at the same time as the photoconductor 1.

By the way, the cleaning roller 6 is constructed by forming a foamed elastic body 6b on a metal shaft 6a, which has a resistance value of about 1 to 100 MΩ, and the metal shaft 6a has D
C-bias is applied.

During image formation, a positive DC bias of about + 500V is applied as a cleaning bias to the cleaning roller 6 via the metal shaft 6a, and the photosensitive member 1
The toner of negative polarity is collected from above and held on the cleaning roller 6. Further, at the time of non-image formation before and after image formation, a negative DC bias is applied to the cleaning roller 6 to bring the surface potential of the photoconductor 1 close to 0 V, so that the toner is returned onto the photoconductor 1 and the cleaning roller 6 is discharged. Remove toner. When the toner is removed from the cleaning roller 6, a negative DC bias is applied to the charging roller 2, and the charging roller 2 is prevented from uniformly charging the photoconductor 1 during the next image formation. Not so polluted. In addition, the transfer residual toner flies near the portion facing the developing device 3 due to the developing bias applied between the developing sleeve 4 and the photoconductor 1, and is scattered in the cloud-shaped toner to be scattered inside the developing device 3. Is taken into.

However, if the image formation is interrupted midway due to some reason, the amount of the residual transfer toner on the photoconductor 1 is much larger than the amount of the residual transfer toner during the normal image formation. Even if the photoconductor 1 is repeatedly rotated, the transfer residual toner cannot be removed from the photoconductor 1 by the start of image formation, and the first image after the interruption is largely disturbed. The reason is,
This is because the cleaning roller 6 does not retain the transfer residual toner on the photoconductor 1 because the bias for returning the toner to the photoconductor 1 is applied to the cleaning roller 6 before the image formation as described above. Yes, in addition to developing device 3
However, since it uses the non-contact developing method, it does not have a high toner collecting capability.

Therefore, in the present embodiment, as a method of removing toner from the surface of the photoconductor 1 when the image formation is interrupted midway, the first transfer paper P after the interruption is used as the cleaning paper for the photoconductor 1. The second and subsequent transfer sheets P were used for normal image formation.

When the transfer paper P is not output from the main body of the image forming apparatus even when a predetermined time has elapsed from the image forming start signal during image formation, the transfer paper P within the image forming apparatus is It is determined that an abnormality has occurred in the conveyance, all the image forming operations are interrupted, and the user is notified of the abnormality by displaying, for example, a blinking lamp. In this embodiment,
A non-volatile memory is provided in the image forming apparatus, and when the image formation is interrupted midway, the fact is stored, and the photoconductor cleaning mode is automatically prioritized and selected when the next image formation is possible. The transfer residual toner on the photoconductor 1 is removed.

By the way, the photoconductor cleaning mode has a sequence as shown in FIG.

That is, at the same time as the photosensitive member 1, the developing sleeve 4, and the cleaning roller 6 are rotationally driven, about -0.5 KV is applied to the transfer roller 5 as a bias having a polarity opposite to that at the time of image transfer, and DC is applied to the charging roller 2. About −200 V is applied, and only DC −100 V is applied to the developing sleeve 4 without applying an AC bias. A DC bias of -1 KV is applied to the cleaning roller 6 so that the toner has a potential relationship such that the toner is transferred onto the photoconductor 1 as in the case of non-image formation.
Apply the degree. Each of these biases is applied to the photosensitive member 1.
The upper transfer residual toner is held on the photoconductor 1, the transfer roller 5, the cleaning roller 6 and the like are not contaminated with the toner, and the developing device 3 does not increase the toner on the photoconductor 1. .

The photoconductor cleaning paper is composed of the transfer roller 5 and the photoconductor 1.
At the same time as entering the pressure contact portion with, the transfer bias applied to the transfer roller 5 is switched, and about +1 KV is applied as the transfer bias of the same + polarity as at the time of image formation to transfer all the toner on the photoconductor 1 to this cleaning paper. To do. Further, with respect to the cleaning bias, the condition of the DC bias such that the toner is transferred onto the photoconductor 1 does not change. After the photoconductor cleaning sheet has passed through the pressure contact portion between the transfer roller 5 and the photoconductor 1, the same normal image forming process as that at the time of image formation is performed.

In the case of an image forming apparatus capable of selecting transfer sheets of different sizes, even if the photoconductor cleaning mode is set so that the transfer sheet of the maximum size among the sizes selectable as the photoconductor cleaning sheet is adopted. good.

As described above, the photoconductor cleaning mode is set in which the transfer residual toner on the photoconductor is removed by transferring it to the photoconductor cleaning paper, and the photoconductor cleaning mode is automatically set after the transfer paper is abnormally conveyed. If the cleaning mode is selected, even if the cleaning roller system is adopted as the photosensitive member cleaning means and the developing device adopts the non-contact developing method, it is always of high quality without fog or image stain. Images can be obtained.

<Second Embodiment> Next, a second embodiment of the present invention will be described.

This embodiment adopts the second photoconductor cleaning mode, and the second photoconductor cleaning mode has a sequence as shown in FIG. This is to transfer the transfer residual toner on the photosensitive member 1 from the photosensitive member 1 to the transfer roller 5 in advance when the transfer paper conveyance abnormality occurs, and transfer the transfer residual toner from the transfer roller 5 to the cleaning paper again. .

The feature of this embodiment is that even if the length of the cleaning paper is short, the situation that the transfer residual toner cannot be completely removed from the photoconductor 1 and the image is contaminated will not occur. This is because the cleaning roller 6 can be used before and after the normal image formation even if the transfer roller 5 does not completely transfer the cleaning paper.

In the second photoconductor cleaning mode, at the same time as the photoconductor 1 and the developing sleeve 4 are rotationally driven, about +1 KV is applied to the transfer roller 5 as the transfer bias of the image transfer condition,
The charging roller 2 has a DC-13 with the same bias as when the image is formed.
00V is applied, and only DC-200V is applied to the developing sleeve 4 without applying an AC bias. Further, a DC bias of about -1000V is applied to the cleaning roller 6 as in the case of non-image formation so that the transfer residual toner is not collected. Each of these biases is set so that the transfer residual toner on the photoconductor 1 is transferred onto the transfer roller 5 and the toner on the photoconductor 1 is not increased by the developing device 3 until the cleaning paper arrives.

The photoconductor cleaning sheet is composed of the transfer roller 5 and the photoconductor 1.
When it enters the pressure contact portion with the transfer roller 5, the transfer bias applied to the transfer roller 5 is switched, and a transfer bias of a negative polarity, which is the reverse polarity to that at the time of image formation, is applied at about −500 V, and all the toner on the transfer roller 5 is removed from this cleaning paper. Transfer to the back. After the photoconductor cleaning paper has passed through the pressure contact portion between the transfer roller 5 and the photoconductor 1, the same image forming process as that at the time of image formation is performed.

As described above, also according to the method of this embodiment, even if the cleaning roller system is adopted as the photosensitive member cleaning means and the developing device adopts the non-contact developing method, the fog or the developing stain is always generated. It is possible to obtain a high-quality image with no image.

<Third Embodiment> Next, a third embodiment of the present invention will be described.

This embodiment adopts the third photoconductor cleaning mode, and the sequence of the third photoconductor cleaning mode is shown in FIG.
Shown in.

In the third photoconductor cleaning mode, the transfer residual toner on the photoconductor 5 when the transfer paper conveyance abnormality occurs is detected by the photoconductor 1.
The toner on the transfer roller 5 is transferred from the transfer roller 5 to the cleaning paper.

The feature of this embodiment is that the transfer residual toner on the photoconductor 1 and the toner possibly remaining on the transfer roller 5 can be removed at the same time, and the front and back surfaces of the cleaning paper can be effectively used.

In the third photoconductor cleaning mode, similarly to the first embodiment, the cleaning sheet is waited for while keeping the residual toner on the photoconductor 1, and when the cleaning sheet comes to the transfer area, the 1
The residual toner after transfer is transferred to the cleaning paper for about two rounds to remove the toner from the photoconductor 1, but the bias setting is switched to the rear end of the cleaning paper until the rear end of the cleaning paper, as in the second embodiment. In this mode, the dirt of No. 5 is transferred to the cleaning paper.

As described above, also in this embodiment, the photoconductor cleaning means adopts the cleaning roller system,
Moreover, even when the developing device also adopts the non-contact developing method, it is possible to always obtain a high-quality image without fog or image stain.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 5 is a sectional view of a laser beam printer which is an image forming apparatus according to the fourth embodiment of the present invention.

In FIG. 5, reference numeral 101 denotes a photosensitive member, and a gear or the like for receiving the rotational drive of the photosensitive member 101 is fixed to the end portion of the photosensitive member. Reference numeral 102 denotes a charging roller as a contact charging member, which contacts the photoconductor 101 and charges the surface of the photoconductor 101 to a predetermined potential. Also 103
Is a developing device, which has a developing sleeve 127 parallel to the photoconductor 101, and neither the developing sleeve 127 nor the toner on the developing sleeve 127 is in contact with the photoconductor 101. Further, 113 is a transfer roller which is a transfer means, and 11
Reference numeral 4 denotes a toner removing member which is a cleaning means for the photoconductor.

In this embodiment, the charging roller 10 is used.
2, a metal shaft 102a and is constituted by a resistive elastic layer 102b in the order of 10 ⁵ Ω · cm coated on the roller-like on its periphery at both ends of the metal shaft 102a is rotatably supported by a bearing (not shown) The charging roller 102 is always in contact with the photoconductor 101. The metal shaft 102a is electrically connected to a charging bias applying power supply 117, and a bias is applied to the charging roller 102 via the metal shaft 102a to charge the surface of the photoconductor 101 to a predetermined potential.

During image formation, the photosensitive member 101 is rotationally driven in the direction of arrow A in FIG. 5 at a predetermined peripheral speed (process speed) based on the image formation start signal. The charging roller 102 is driven to rotate as the photoconductor 101 rotates. D as a charging bias for the charging roller 102
By applying a bias in which AC-1800V is superimposed on C-750V, the surface of the photoconductor 101 is about -75.
It is charged to 0 V (at this time, the charging bias applying power source 1
The switch Tl in 17 is connected to the SWl side).

Then, the charged surface of the photoconductor 101 is exposed with image information by a laser beam which is an exposing means output from the exposure generating means of the apparatus main body, and an exposed portion on the surface of the photoconductor 101 is exposed. When the surface potential drops to about -150 V, an electrostatic latent image corresponding to the exposed image is sequentially formed on the surface of the photoconductor 101.

Next, the electrostatic latent image is sequentially developed as a toner image by the developing device 103. The developing device 103 includes a rotating developing sleeve 127, a developing container 112 that holds the developing sleeve 127 and magnetic toner 118, a magnet roll 111 inside the developing sleeve 127 fixed to the developing container 112, and toner on the developing sleeve 127. The magnetic blade 131 regulates the amount. The developing sleeve 127 is electrically connected to a developing bias applying power source (not shown), and is arranged in parallel with the photoconductor 101 with a predetermined gap. Toner 118 is
By the magnetic force of the magnet roll 111, the developing sleeve 1
27, and is charged to a predetermined polarity (negative in this embodiment) by frictional charging with the surface of the developing sleeve 127.

At the time of image formation, the developing sleeve 127 is rotationally driven in the direction of arrow H in FIG. 5, and the toner 118 applied on the developing sleeve 127 is conveyed to the vicinity of the photoconductor 101. Development sleeve 127 conveyed near the photoconductor 101
The layer thickness of the upper toner 118 is regulated by the magnetic blade 131. Further, a superimposed voltage of a predetermined DC voltage and AC voltage is applied to the developing sleeve 127 as a developing bias. In this embodiment, the developing bias is 130
0Vpp, 2000Hz AC bias and DC-400
By applying V, toner is made to adhere to the exposed portion of the photoconductor 101 and the electrostatic latent image is visualized as a toner image.

Next, between the transfer roller 113 pressed against the photosensitive member 101 and the photosensitive member 101, the transfer paper P and the photosensitive member 10 are connected.
The toner image on No. 1 is pressure-contacted in synchronization with each other, and a transfer bias is applied by the transfer bias power source 132 to transfer the toner image from the photoconductor 101 onto the transfer paper P. The transfer roller 113 is configured by forming an elastic body 113b having a resistance value of about 10 ⁷ to 10 ¹⁰ Ω · cm in a cylindrical shape on the outer circumference of a conductive metal shaft 113 a, and
Is contacted with a predetermined contact pressure. In addition, the transfer roller 113
Are supported in the same manner as the charging roller 102, and a transfer bias is applied thereto.

Thus, at the time of image transfer, a transfer bias of about +1 KV is applied to the transfer roller 113 (at this time, the switch T2 in the transfer bias application power supply 132 is connected to the SW5 side) and the toner. Most of the image is transferred onto the transfer paper P, and the photoconductor 10 not transferred
The transfer residual toner on No. 1 is small.

The very small amount of transfer residual toner on the photosensitive member 101 is agitated and dispersed by the toner removing member 114 and is used in the next image forming process.

The toner removing member 114 is constantly in pressure contact with the photosensitive member 101. The toner removing member 114 is a metal holder 114a in which a medium resistance conductive fiber 114b is formed, has a resistance value of about 1 to 100 MΩ, and a DC bias is applied to the metal holder 114a.

At the time of image formation, a cleaning bias of about +500 V is applied to the toner removing member 114,
Negative polarity toner is collected from the photoconductor 101 and held on the toner removing member 114. Further, at the time of non-image formation before and after image formation, a negative DC bias is applied to the transfer roller 113 (at this time, the switch T2 in the transfer bias application power source 132 is connected to the SW4 side), and the photoconductor 101 The toner is returned to and the toner is removed from the toner removing member 114.

When the toner is removed from the toner removing member 114, the charging roller 102 is not so dirty that it hinders the uniform charging of the photosensitive member 101. In addition, the transfer residual toner is generated in the developing sleeve 1 in the vicinity of a portion facing the developing device 103.
The toner flies by the developing bias applied between the photosensitive member 101 and the photosensitive member 101, and is mixed with the toner in a cloud shape and taken into the developing device 103 or becomes a toner for forming a toner image.

However, when the image formation is interrupted during some reason, the amount of the transfer residual toner on the photoconductor 101 is large, and therefore, even if the photoconductor 101 is repeatedly rotated, the photoconductor is not started until the image formation is started. The transfer residual toner cannot be removed from above 101, and the first image after the interruption is largely disturbed.
This is because the toner removing member 1 as described above is formed before image formation.
This is because the toner removing member 114 does not hold the transfer residual toner on the photoconductor 101 because a bias for returning the toner to the photoconductor 101 is applied to the photoconductor 101.
This is because the developing device 103 employs the non-contact developing method and thus does not have a high toner collecting capability.

Further, in the present embodiment, the transfer roller 11
A transfer roller scraper 133 and an untransferred toner collecting container 134 are provided in the vicinity of 3. The transfer roller scraper 133 has a length that makes contact with the entire area of the transfer roller 113 in the longitudinal direction, and is made of a material such as phosphor bronze plate or rubber. In the normal image forming process, the transfer roller scraper 133 and the untransferred toner collecting container 134 are in the position (e) shown by the chain line in FIG. 5, and at this time, the transfer roller scraper 133 is in contact with the transfer roller 113. There is no state.

Next, the feature of this embodiment, that is, the transfer paper P
A method of collecting the transfer residual toner on the photosensitive member 101 when the image forming apparatus is stopped during development due to the occurrence of the jam will be described.

In the present embodiment, in addition to the normal sequence, a return sequence that is prioritized immediately after clearing the jam is provided.

The return sequence is performed immediately after the transfer sheet P is removed after the image forming apparatus is stopped due to the jam of the transfer sheet P and has priority over the normal sequence. At the time of jam, the toner 119 immediately after development remains on the photoconductor 101.

The transfer roller scraper 133 and the untransferred toner collecting container 134 move simultaneously in the direction of arrow I in FIG. 5, and the transfer roller scraper 133 comes into pressure contact with the transfer roller 113 (see the solid line (f) in FIG. 5). State). Then, the photoconductor 101 rotates in the direction of arrow A in FIG. At the same time, in the charging bias power supply 117, the switch T1 switches the AC bias + DC bias application (SW1) in the normal sequence to the DC bias application (SW2). In the normal sequence (SW1), the AC voltage component Vp
Sine wave bias of p = 2000V, DC voltage component Vdc = -600V, charging frequency Vf = 240Hz, DC voltage component Vdc = -13 in the restoration sequence (SW2).
It is designed to apply 00V to the charging roller 102.

The transfer roller 1 is rotated by the rotation of the photosensitive member 101.
13 also rotates in the direction of the arrow in FIG. 5, and the untransferred toner 119 contacts the transfer roller 113. At this time, the switch T2 in the transfer roller bias power source 132 is connected to SW5, a positive polarity bias is applied to the transfer roller 113, and the untransferred toner 119 on the photoconductor 101 is charged to a negative polarity. Therefore, the untransferred toner 119 is transferred to the transfer roller 113.

The untransferred toner 119 transferred from the photoconductor 101 onto the transfer roller 113 moves with the rotation of the transfer roller 113, is scraped off the surface of the transfer roller 113 by the transfer roller scraper 133, and is transferred to the untransferred toner collecting container 134. Will be recovered in.

The surface of the transfer roller 113 is almost completely cleaned by the transfer roller scraper 133, and when the transfer roller 113 comes into contact with the photosensitive member 101 next time, the untransferred toner 119 on the photosensitive member 101 is sufficiently transferred again. It becomes possible. In addition, at least from the developing position to the transfer position, preferably for one rotation of the photoconductor 101 or more,
This return sequence is continued.

Toner removing member 114 during the return sequence
Since a bias for returning the toner to the photoconductor 101 is applied to the photoconductor 101, the toner removing member 114 transfers the transfer residual toner held in the toner removing member 114 onto the photoconductor 101. During this sequence, the toner removing member itself can be cleaned. Incidentally, the developing bias is not applied during this return sequence. Further, in this embodiment, since the non-contact developing method is adopted as the developing method, the toner is not developed on the photoconductor 101 during the returning sequence unless the bias is applied, and therefore, the photoconductor 101 is not developed. Effective cleaning is possible.

After sufficient recovery of the untransferred toner 119, the transfer roller scraper 133 and the untransferred toner recovery container 1
34 returns to the normal sequence position (position (e) in FIG. 5). Further, the switch T in the charging bias applying power supply 117
1 also switches to the normal sequence (SW1), and the return sequence ends.

In this example, the A4 portrait image was printed by a single print. Jam was intentionally generated about once every 500 sheets while the 100,000 sheets of various print patterns were being used.
There was no problem such as stains and charging failure. Further, the amount of toner in the untransferred toner collecting container 134 is about 40 g,
The volume of the image forming apparatus is about 1/10 of the cleaner volume required for durability of 100,000 sheets, and the image forming apparatus can be downsized and the space can be saved.

Even in the non-contact development, an effective toner collecting method can be realized by transferring the untransferred toner on the photosensitive member to the transfer roller once only during the recovery sequence at the time of jam and cleaning it.

Although a scraper is used as the cleaning means for the transfer roller in this embodiment, a fur brush, a cleaning roller made of foam, a magnetic brush-like cleaning roller, and a biased conductive cleaning roller. Needless to say, a cleaning means such as a magnet roller can be used when a cleaning roller having a different peripheral speed is used, or when magnetic toner is used.

<Fifth Embodiment> Next, a fifth embodiment of the present invention will be described with reference to FIGS. 6 and 7. 6 and 7 are schematic sectional views of an image forming apparatus (laser beam printer) using the non-contact developing method.

In the laser beam printer according to this embodiment, the photoconductor 201, which is an image carrier, is arranged so as to rotate in the direction of arrow A, and the photoconductor 201 is charged by the primary charger 202 and exposed. A latent image is formed by means 203. In addition, a developing sleeve 205 as a toner carrier and a toner 206 are housed inside a developing container 204 having an opening facing the photoconductor 201.

In the present embodiment, description will be given below on the assumption that the surface of the photoconductor 201 is negatively charged and the image is exposed and negatively developed by reversal development.

A magnet roller 214 is fixedly incorporated in the developing sleeve 205 so as to be coaxial with the developing sleeve 205.
Has a mechanism for rotating in the direction of arrow H.

Further, the toner 206 is a magnetic toner, which is a D blade 2 which is a toner regulating member using a magnetic material.
Due to the rotation of the developing sleeve 205 in the direction of arrow H, the toner thin layer 211 (coat thickness h = about 100 to 300 μm) is formed on the developing sleeve 205.
To form. At this time, the developing sleeve 205 and the photoconductor 201 are kept in a non-contact state between the thin toner layer 211 on the developing sleeve 205 and the photoconductor 201, so that the minute gap i (200
˜500 μm) (provided that i
> H) (hereinafter, the developing sleeve 205 and the photoconductor 201 are referred to as SD).

The agitator 213 makes a motion such as rotation in the developing container 204 to block the toner 206 (a phenomenon in which the toner 206 is aggregated in the vicinity of the developing sleeve 205 and the toner 206 is not supplied to the developing sleeve 205). Prevent. A developing bias power source 216 applies a developing bias to the developing sleeve 205 (DC component:
-100 to -700V, AC component: 1000 to 2000
Vpp, 1500 to 2500 Hz) is applied, and the latent image on the photoconductor 201 is developed by the toner in the toner thin layer 211 to be visualized as a toner image. Then, the developed toner image is transferred onto the transfer paper P by the transfer means 208, and is fixed onto the transfer paper P by the fixing means 209. It should be noted that the toner slightly remaining on the photoconductor 201 after the transfer is dispersed by the toner removing member 210.

Next, the feature of the present embodiment, that is, the mechanism of the method for collecting the transfer residual toner on the photoconductor when the image forming apparatus is stopped during development due to the jam of the transfer paper will be described.

In the present embodiment, in addition to the normal sequence, a return sequence that is prioritized immediately after clearing a jam is provided.

First, the solenoid 212 operates the D blade 20.
7 in the direction of arrow B for a predetermined distance (about 0.3 to 3.0 mm)
Just move. Then, the developing sleeve 20 shown in FIG.
5 and the distance between the D blade 207 (hereinafter referred to as S-B)
The distance a (about 200 to 500 μm) is the distance b (about 0.5 to 3.0 mm) as shown in FIG. 7.

After that, when the developing sleeve 205 is rotated in the direction of arrow H, the thickness b of the toner thin layer 211 on the developing sleeve 205 becomes sufficiently thick, and the toner thin layer 211 does not contact as shown in FIG. It will come into sufficient contact with the existing photoconductor 201. At this time, the primary charger 202, the transfer means 208, and the removing member 210 are moved in the C, D, and E directions by a solenoid (not shown) or the like, and are separated from the photoconductor 201. As a result, the primary charger 202, the transfer unit 208, and the removing member 210 are not contaminated by the untransferred toner and the transfer residual toner on the photoconductor 201 during the return sequence. Then, the untransferred toner and the untransferred toner on the photoconductor (potential: about −100 to −800 V) 201 are developed sleeve 205.
The developing sleeve 205 is applied (-
100 to 400 V), the developing sleeve 205 rotates in the direction of arrow H and the photoconductor 201 rotates in the direction of arrow A for a certain period of time, so that untransferred toner and untransferred toner on the photoconductor 201 become toner on the developing sleeve 205. Taken in and removed.

After the transfer residual toner and the untransferred toner on the photoconductor 201 are sufficiently collected (usually, it is sufficient if the photoconductor 201 makes two revolutions or more, so in this embodiment, it is set to four revolutions). The blade 207 descends again to return the space between S and B to the normal interval a (about 200 to 500 μm). Then, the developing sleeve 205 rotates in the direction of arrow H, and the toner thin layer 211 is in the original thin layer state (layer thickness 100 to 100).
(About 300 μm), the thin toner layer 211 on the developing sleeve 205 and the photoconductor 201 return to the non-contact state again.
After that, the primary charger 202, the transfer means 208, and the removing member 210 are also returned to the state of FIG. 6, and printing is restarted in the normal sequence.

By the above method, even in the non-contact development, the toner can be effectively collected by bringing the toner into contact with the photosensitive member during the recovery sequence when the jam occurs.

<Sixth Embodiment> Next, a sixth embodiment of the present invention will be described with reference to FIGS. 8 and 9 are schematic cross-sectional views of the main part of the laser beam printer according to this embodiment.

The photosensitive member 201, which is an image bearing member, is indicated by an arrow A in the figure.
The photoconductor 20 is arranged so as to rotate in the direction.
1 is charged by the primary charger 202, and the exposure unit 20
A latent image is formed by 3. Further, in a developing container 204 having an opening facing the photoconductor 201, a developing sleeve 205 as a toner carrier and a toner 206 are stored.

In this embodiment, the following description will be made on the assumption that the photoconductor 201 is negatively charged and the latent image formed on the photoconductor 201 is subjected to reversal development using an image exposure negative toner.

A magnet roller 214 is fixedly incorporated in the developing sleeve 205 so as to be coaxial with the developing sleeve 205.
Has a mechanism for rotating in the direction of arrow H. The toner 206 is a magnetic toner, and the D blade 2 is a toner regulating member.
07, the developing sleeve 205 rotates in the direction of the arrow H to form a thin toner layer 211 (coat thickness k: about 20 to 200 μm) on the developing sleeve 205. At this time, in order that the thin toner layer 211 on the developing sleeve 205 and the photoconductor 201 are in a non-contact state, m between S and D (200 to 5).
The developing sleeve 205 is disposed with a diameter of about 00 μm (however, m> k).

Further, in this embodiment, the toner regulating member D
As the blade 207, an elastic blade formed by integrally molding silicon rubber on a SUS plate was used. The agitator 213 makes a motion such as rotation in the developing container 204 to prevent the toner 206 from blocking.

A developing bias power source 216 applies a developing bias to the developing sleeve 205 (DC component: -100 to -7).
00V, AC component: 1000 to 2000Vpp, 150
0 to 2500 Hz) is applied, and the latent image on the photoconductor 201 is developed by the toner in the toner thin layer 211 to be visualized as a toner image. Then, the developed toner image is transferred onto the transfer paper P by the transfer means 208, and is fixed onto the transfer paper P by the fixing means 209. It should be noted that the toner remaining on the photoconductor 201 after the transfer is very slightly dispersed by the toner removing member 210.

Next, the feature of this embodiment, that is, the mechanism of the method for collecting the transfer residual toner on the photoconductor when the image forming apparatus is stopped during development due to the jam of the transfer paper will be described.

In the present embodiment, in addition to the normal sequence, a return sequence that is prioritized immediately after clearing a jam is provided.

First, as shown in FIG.
When 2 moves the D blade unit 215 in the direction of arrow F by a predetermined distance (about 0.3 to 3.0 mm), the linear pressure between the D blade 207 and the developing sleeve 205 weakens.

By the way, in the toner application at the contact portion between the D blade 207 and the developing sleeve 205, the contact pressure changes the coating amount and the coat thickness, and when the contact pressure decreases, the coat thickness increases. Sleeve 205
Is rotated in the direction of arrow H, the thickness m of the toner thin layer 211 on the developing sleeve 205 becomes sufficiently thick, and the toner thin layer 211 is not in contact with the photoreceptor 2 as shown in FIG.
01 will come into sufficient contact. At this time, the primary charger 202, the transfer unit 208, and the removing member 210 are moved in the C, D, and E directions of FIG. As a result, the primary charger 202, the transfer unit 208, and the removing member 210 are not contaminated by the untransferred toner and the transfer residual toner on the photoconductor 201 during the return sequence.
Further, the untransferred toner and the untransferred toner on the photoconductor (potential: approximately −100 to −800 V) 201 are developed sleeve 205.
The developing sleeve 205 is applied (-
100 to 200 V), and the developing sleeve 205 has an arrow H.
Direction, the photoconductor 201 rotates in the direction of arrow A for a certain period of time, so that the transfer residual toner and the untransferred toner on the photoconductor 201 are taken into the toner on the developing sleeve 205 and removed.

After the untransferred toner and the untransferred toner on the photoconductor 201 are sufficiently collected (usually, it is sufficient if the photoconductor 201 makes two or more revolutions, so in this embodiment, it is set to four revolutions). The blade unit 215 returns to its original position as shown in FIG. As a result, the linear pressure between the D blade 207 and the developing sleeve 205 is increased, and the developing sleeve 20
5 rotates in the direction of arrow H, and toner thin layer 211
Returns to the original thin layer state (layer thickness of about 20 to 200 μm),
Thin toner layer 211 on developing sleeve 205 and photoreceptor 20
1 returns to the non-contact state again. Then, the primary charger 20
2. The transfer unit 208 and the removing member 210 are also returned to the normal state, and printing in the normal sequence is restarted.

According to the above method, even in the non-contact development, it is possible to effectively collect the toner by bringing the toner into contact with the photosensitive member during the recovery sequence when the jam occurs.

Here, FIG. 10 shows the D blade unit 21.
5 is an enlarged view of a contact state between the developing sleeve 205 and the developing sleeve 205. As in the present embodiment, the plate-shaped D blade 207 contacts the developing sleeve 205 to form the toner thin layer 211 on the developing sleeve 205. In this case, the coating layer thickness depends on the linear pressure N between the D blade 207 and the developing sleeve 205 and the nip free length c (the length from the end of the nip portion d to the edge portion of the D blade 207). That is, the layer thickness of the toner thin layer 211 increases due to the decrease in the linear pressure N and the increase in the nip free length c and the wedge-shaped portion e sandwiched by the developing sleeves 205.

In this embodiment, the D blade unit 21
5 is moved to move the D blade 207 and the developing sleeve 205.
Although the linear pressure N between them was only weakened, the nip free length c
The toner thin layer 211 may be thickened by moving the D blade 207 in the direction of the arrow R so as to extend the width of the toner and reducing the linear pressure N and increasing the wedge-shaped portion e.

<Seventh Embodiment> Next, a seventh embodiment of the present invention will be described with reference to FIGS. 11. FIG. 11 is a schematic sectional view of the main part of the laser beam printer according to this embodiment.

As shown in FIG. 11, the photoconductor 201, which is an image carrier, is arranged so as to rotate in the direction of arrow A. The photoconductor 201 is charged by the primary charger 202 and is exposed by the exposing means 203. A latent image is formed. or,
In a developing container 204 having an opening facing the photoconductor 201, a developing sleeve 205 as a toner carrier and a toner 206 are housed.

In the present embodiment, it is assumed that the photosensitive member 201 is negatively charged and the latent image formed on the photosensitive member 201 is subjected to reversal development by using image exposure negative toner. Is a magnet roller 2
14 is fixed and incorporated so as to be coaxial with the developing sleeve 205. This developing sleeve 205 is indicated by an arrow H.
It has a mechanism that rotates in the direction. The toner 206 is magnetic toner, and the developing blade 205 is rotationally moved in the direction of arrow H by the D blade 207 which is a toner regulating member using a magnetic material, and the toner thin layer 21 is formed on the developing sleeve 205.
1 (coat thickness h: about 100 to 300 μm) is formed. At this time, the thin toner layer 21 on the developing sleeve 205 is
1 and the photoconductor 201 are in non-contact with each other, the developing sleeve 205 is arranged with an SD between i (about 200 to 500 μm) (however, i> h). Agitator 2
13 performs movement such as rotation in the developing container 204,
The blocking of the toner 206 is prevented.

The developing bias is supplied to the developing sleeve 205 by the developing bias power source 216 (DC component: -100 to-).
700V, AC component: 1000-2000Vpp, 15
(0 to 2500 Hz) is applied, and the latent image on the photoconductor 201 is developed by the toner in the toner thin layer 211 to be visualized as a toner image. The developed toner image is transferred onto the transfer sheet P by the transfer unit 208, and the fixing unit 2
The image is fixed on the transfer paper P by 09. It should be noted that the toner remaining on the photoconductor 201 after the transfer is very slightly dispersed by the toner removing member 210.

Next, the feature of the present embodiment, that is, the mechanism of the method for collecting the transfer residual toner on the photosensitive member when the image forming apparatus is stopped during development due to the jam of the transfer paper will be described.

In the present embodiment, in addition to the normal sequence, a return sequence that is prioritized immediately after clearing a jam is provided.

12 and 13 show a state in which a jam has occurred (transfer paper is not shown). Hereinafter, the recovery sequence that is prioritized immediately after clearing the jam will be described.

First, the developing sleeve 205 is translated in the direction of arrow G by a solenoid (not shown) or the like, and the distance between SD is changed from f (about 200 to 500 μm) shown in FIG.
Sandwiched between g (about 300 μm, f> g)
The photoconductor 201, which was not in contact with the toner thin layer 211 on the developing sleeve 205 until then, comes into contact with the toner thin layer 211. At this time, the primary charger 202, the transfer unit 208, and the removing member 210 are moved in the C, D, and E directions shown in FIG.
Move away from the photoconductor 201. As a result, the primary charger 20
2. The transfer unit 208 and the removing member 210 are not contaminated by the untransferred toner and the transfer residual toner on the photoconductor 201 during the return sequence.

Then, the photosensitive member (potential: about -100 to -8)
00V) 201, the untransferred toner and the untransferred toner are applied to the developing sleeve 205 in a direction to be attracted to the developing sleeve 205 (−100 to 400V). By rotating in the direction for a predetermined time, the transfer residual toner and the untransferred toner on the photoconductor 201 are taken in by the toner on the developing sleeve 205 and removed.

After the untransferred toner and the untransferred toner on the photoconductor 201 are sufficiently collected (usually, it is sufficient if the photoconductor 201 makes two revolutions or more, so in the present embodiment, it is set to four revolutions). The sleeve 205 returns to the same position as in FIG. 12 again, and becomes f again between SD. Here, the thin toner layer 211 on the developing sleeve 205 and the photoconductor 201 return to the non-contact state again. After that, the primary charger 202, the transfer unit 208, and the removing member 210 are also returned to the state shown in FIG. 12, and printing in the normal sequence is restarted.

By the above method, even in the non-contact development, the toner can be effectively collected by bringing the toner into contact with the photosensitive member during the recovery sequence when the jam occurs.

<Eighth Embodiment> An eighth embodiment of the present invention will be described below with reference to FIGS. 14 to 16.

FIG. 14 is a schematic sectional view of an image forming apparatus according to this embodiment. In this image forming apparatus, the photoconductor 3 is used.
01, a charging roller 302, a developing device 307, a process cartridge 343 in which a process device including a toner removing member 314 is incorporated, a transfer roller 313, and a fixing device 31.
5. Laser scanner 304 and mirror 306 as optical systems
And so on.

Next, the image forming process of this image forming apparatus will be described below.

The image forming apparatus according to this embodiment includes a photoconductor 301 as a member to be charged (image carrier). The diameter of the photoconductor 301 is 30 mm, which means that the photoconductive photosensitive layer 3 is formed on the surface of the conductive substrate 301b made of aluminum.
24 mm in the direction of arrow A in the figure.
It is driven to rotate at a process speed of / sec.

Further, the photosensitive member 301 is negatively charged uniformly by the charging roller 302 in the course of rotation, and then the time series of the target image information sent from the video controller (not shown) output by the laser scanner 304. Laser light 305 corresponding to an electric digital image signal is used to perform scanning exposure with a resolution of 300 dpi.
An electrostatic latent image is formed on the surface via a mirror 306 installed in the main body of the image forming apparatus.

The electrostatic latent image formed on the photoconductor 301 is reversely developed by the toner 308 carried on the developing sleeve 310 in the developing device 307 to be visualized as a toner image.

The toner image is transferred onto the transfer paper P by the action of the transfer roller 313, and the transfer efficiency at this time is about 97%. Then, the transfer paper P having the toner image transferred thereto is separated from the photoconductor 301 and introduced into the fixing device 315, where the toner image is fixed there, and then the transfer paper P is discharged to the outside of the image forming apparatus.

On the photoconductor 301 after the toner image transfer, the transfer residual toner slightly left by the toner removing member 314 is disturbed and dispersed, and the next image forming process is performed.

By the way, the developing device 307 employs a non-contact developing system, and includes a developing sleeve 310 and a toner accommodating chamber 303 which are toner carrying members for carrying the toner 308 and carrying it to the photosensitive member 301. have.
The developing sleeve 310 is non-magnetic and is made of, for example, aluminum, stainless steel, or the like, and a magnet roll 311 is arranged inside thereof.

Further, the developing sleeve 310 is rotatably supported by a bearing (not shown), and in this embodiment, it rotates in the direction of arrow H at a peripheral speed of 36 mm / sec.
Further, the developing sleeve 310 is connected to a power source 312 capable of superimposing an AC bias on a DC bias, and in this embodiment, a DC voltage component Vdc = -400V and an AC voltage component V.
A rectangular wave bias with pp = 1000 V and frequency = 1800 Hz was applied.

The developing sleeve 310 is supported opposite to the photoconductor 301 with a predetermined developing interval, and the developing interval is set to about 200 μm.

The doctor blade 309 for regulating the layer thickness of the toner 308 on the developing sleeve 310 has a thickness of 0.9.
mm of urethane rubber having a hardness of 67 ° is used.
Give a proper tribo to. In addition, doctor blade 309
Alternatively, a metal elastic body such as phosphor bronze or stainless steel, or a synthetic resin elastic body such as polyethylene terephthalate may be used.

When the developing bias is supplied to the developing sleeve 310, the toner 308 flies near the position closest to the photosensitive member 301 (hereinafter referred to as the developing area),
The latent image on the photoconductor 301 is developed.

By the way, in this embodiment, a magnetic one-component toner is used as the toner 308.
8 is accommodated in the toner accommodating chamber 303. The toner 308 in the toner storage chamber 303 is attracted to the developing sleeve 310 by the magnetic force of the magnetic pole S2 of the magnet roll 311 contained in the developing sleeve 310. In this embodiment, the magnetic pole S2 used has a magnetic force of a peak value of 700 gauss.

Next, the feature of the present embodiment, that is, the mechanism of the method of collecting the transfer residual toner on the photoconductor when the image forming apparatus is stopped during the development due to the jam of the transfer paper will be described.

FIG. 15 is a schematic diagram of the process cartridge 343 showing the features of this embodiment.

As shown in FIG. 15, the process cartridge 343 is provided with a photosensitive member 301, a charging roller 302, a charging bias power source 317, a toner removing member 314, a transfer roller 313, and a developing device 307.

In the present embodiment, in addition to the normal sequence, a return sequence that is prioritized immediately after clearing a jam is provided.

FIG. 15 shows a state in which a jam has occurred (the transfer sheet is not shown). Hereinafter, the recovery sequence that is prioritized immediately after clearing the jam will be described in detail.

The return sequence is performed prior to the normal sequence immediately after the image forming apparatus is stopped due to a jam of the transfer sheet and the transfer sheet is removed. When a jam occurs, the toner 319 immediately after development remains on the photoconductor 301. Immediately after the jam is returned, the transfer roller 313 moves in the direction of arrow C in the drawing and the toner removing member 314 moves in the direction of arrow B in the drawing, so that they are not in contact with the photoconductor 301.

Then, the photosensitive member 301 rotates in the direction of arrow A in the figure. At the same time, in the charging bias power source 317, the switch T switches from the normal sequence AC bias + DC bias application (SW1) to the DC bias application (SW2). AC voltage component V in the normal sequence (SW1)
pp = 2000V, DC voltage component Vdc = -600V,
A sine wave bias with a charging frequency Vf = 240 Hz is applied to the DC voltage component Vdc = −1 in the restoration sequence (SW2)
It is designed to apply 300V to the charging roller 302.

As the photoconductor 301 rotates, the transfer residual toner 319 comes into contact with the charging roller 302. Even if the transfer residual toner 319 on the photoconductor 301 has toner positively charged by the transfer roller 313, the charging roller 30
By the negative DC bias acting on 2, the charging roller 3
02 It is possible to charge negatively on the upstream side of the contact portion, and therefore, the charging roller 302 is less contaminated by toner adhesion.

Further, the developing sleeve 310 is stopped, and the magnet roll 311 disposed inside the developing sleeve 310 is rotated 180 ° in the direction of arrow D in the figure. By this operation, the lump of toner held by the S2 pole is generated between the developing sleeve 310 and the photoconductor 301 (hereinafter referred to as S
It is transported to the space between -D) to fill the gap. In this state, the toner is in contact with the photoconductor 301. The toner layer thickness is regulated by the gap L between the developing sleeve 310 and the lower jaw 316 of the developing device 307.

Since the toner is not conveyed unnecessarily due to the above toner regulation, the toner does not leak from the process cartridge 343 in the above sequence.
In this embodiment, L = 500 μm is set.

FIG. 16 shows a state in which the return sequence is being executed.

The toner 320 conveyed by the S2 pole is in contact with the photoconductor 301 filling the space between SD and the transfer residual toner 31 conveyed by the rotation of the photoconductor 301.
9 are collected. In order to completely collect the transfer residual toner 319 on the photoconductor 301 by the toner 320 filling the space between S and D, it is desirable to stop the photoconductor 301 after 2.0 rotations or more. Therefore, in this embodiment, It was set to stop at 4 rotations. After the photoconductor 301 stops, the magnet roll 3
Reference numeral 11 makes two rotations in the direction opposite to the direction of the arrow D in the drawing, and returns to the position of the normal sequence. At the same time, the transfer residual toner 319
The toner 320 containing the toner is collected in the developing device 307,
The collection of the transfer residual toner 319 on the photoconductor 301 is completed.

After the transfer residual toner 319 is collected, the transfer roller 313 and the toner removing member 314 return to the position of the normal sequence. Further, the switch T in the charging bias power source 317 is also switched to the normal sequence (SW1), and the restoration sequence is completed.

Thus, in this example, the A4 vertical image was printed by a single print. During the endurance of 4000 sheets, a jam was intentionally generated about once every 500 sheets.
Problems such as backside smearing of the transfer paper by the transfer roller 313, charging failure, and toner leakage from the process cartridge 343 did not occur.

Therefore, according to the above method, even in the non-contact development, the toner can be effectively collected by bringing the toner into contact with the photosensitive member during the recovery sequence when the jam occurs.

<Ninth Embodiment> Next, a ninth embodiment of the present invention will be described with reference to the accompanying drawings.

The image forming process in this embodiment is the same as the eighth embodiment.
Since it is almost the same as the embodiment, the description thereof is omitted, and the characteristic of this embodiment, namely, the transfer residue on the photoconductor when the image forming apparatus is stopped during the development due to the jam of the transfer paper occurs. The mechanism of the toner collection method will be described.

FIG. 17 is a schematic configuration diagram of a process cartridge showing the features of this embodiment.

In FIG. 17, the same elements as those shown in FIGS. 15 and 16 are designated by the same reference numerals.

FIG. 17 shows a state in which a jam has occurred (transfer paper is not shown). Hereinafter, the recovery sequence that is prioritized immediately after clearing the jam will be described in detail.

Since the restoration sequence is almost the same as that of the eighth embodiment, only different points will be described below.

In this embodiment, the developing sleeve 327 has a function of conveying toner between SD.

In the return sequence, the developing sleeve 327 starts rotating in the arrow A direction in the drawing at the same time as the photosensitive member 301 rotates in the arrow E direction in the drawing at a speed of 12 mm / sec.
That is, the developing sleeve 327 rotates in the opposite direction to the case of the normal sequence. Therefore, the toner 328 in the developing device 329 is SD by the developing sleeve 327.
Transported in between. The toner layer thickness is the developing sleeve 327.
And the lower jaw 316 of the developing device 307. That is, in the gap F, the amount of toner conveyed from the lower portion of the developing device 307 to the developing area sufficiently passes between SD and is sufficiently in contact with the photoconductor 301, and the transfer residual toner 3
It is set so that 19 can be collected.

Since the toner 328 is not conveyed more than necessary due to the above toner regulation, the toner does not leak from the process cartridge 343 by the above sequence. In this embodiment, F = 400 μm is set. The conveyed toner 328 is kept sufficiently in contact with the photoconductor 301.

FIG. 18 shows a state in which the return sequence is being executed.

The toner 328 carried by the developing sleeve 327 fills the SD space and collects the transfer residual toner 319 carried by the rotation of the photoconductor 301 so as to be scraped off. The photoconductor 301 has a sufficient amount of transfer residual toner 3
After 19 is collected, it makes three revolutions and then stops. Photoconductor 30
The toner 328 containing 1 is collected in the developing device 307. At this point, the collection of the transfer residual toner 319 on the photoconductor 301 is completed.

After the transfer residual toner 319 is collected, the transfer roller 313 and the toner removing member 314 return to the position of the normal sequence. Further, the switch T in the charging bias power source 317 is also switched to the normal sequence (SW1), and the restoration sequence is completed.

In the present embodiment, in the returning sequence, the developing sleeve 327 successively conveys the toner 328 between the SD and the SD, and continuously collects the residual toner 319 on the photoconductor 301 so that the residual toner 319 is scraped off. There is an advantage that the recovery capability of the toner 319 is large.

In this example, the A4 vertical image was printed by single printing. During the endurance of 5000 sheets, 10
Jam was intentionally generated about once per 00 sheets, but problems such as backside smearing of the transfer paper by the transfer roller 313, charging failure, and toner leakage from the process cartridge 343 did not occur.

Therefore, according to the above method, even in the non-contact development, the toner can be effectively collected by bringing the toner into contact with the photosensitive member during the recovery sequence when the jam occurs.

<Tenth Embodiment> Next, a tenth embodiment of the present invention will be described with reference to FIGS.

FIG. 19 is a schematic sectional view of the main part of the image forming apparatus according to this embodiment. In the image forming process of this image forming apparatus, the process speed of the photoconductor 301 is 55 mm /
Since it is almost the same as that of the eighth and ninth embodiments except for sec, the description thereof is omitted, and the developing process different from the eighth and ninth embodiments will be described below.

The developing device 321 shown in FIG. 19 comprises a two-component developer 334, a stirring member 322, a developing sleeve 330 and a magnet roll 331.

The two-component developer 334 stored in the developing device 321 is a mixture of toner and microcarrier, and the toner is sufficiently contacted with the microcarrier by being sufficiently agitated by the agitating member 322. However, it is triboelectrically charged and has a uniform tribo suitable for development.

As the toner of the two-component developer 334, a non-magnetic toner having an average particle diameter of about 10 μm is used. As the microcarrier, an average particle size of about 20 μm and magnetic powder dispersed in resin is used.

The mixing ratio of the toner of the two-component developer 334 and the microcarrier, that is, the T / C ratio is maintained at an optimum value, for example, 10% by controlling the toner replenishment based on the signal of the ATR (not shown). To be done.

The well-stirred two-component developer 334 is
The developing sleeve 330 is rotated in the direction of the arrow G in the drawing, and the magnet roll 331 in the developing sleeve 330 is also rotated in the direction of G, so that the layer thickness is regulated to a uniform layer thickness due to the relative rotational speed difference between the developing sleeve 330 and the magnet roll 331. It is transported while receiving. The microcarriers form ears on the developing sleeve 330, and the toner adheres to the microcarriers. AC on the developing sleeve 330
When the bias + DC bias is applied, toner and microcarriers fly from the developing sleeve 330 and adhere to the latent image on the photoconductor 301, whereby the latent image is visualized as a toner image.

In this embodiment, the developing sleeve 330 has a diameter of 16 mm and rotates at a peripheral speed of 12 mm / sec, and the magnet roll 331 rotates at a peripheral speed of 440 mm / sec.

The photosensitive member 301 and the developing sleeve 330 are
The developing gaps are opposed to each other with a predetermined developing gap, and in the present embodiment, the developing gap is set to 900 μm (the vicinity of this adjacent portion is called a developing region).

In this developing area, the two-component developer 3
34 and the photoconductor 301 are not in contact with each other.

The developing bias acting on the developing sleeve 330 is AC bias + DC bias, and the power source 342.
AC voltage component Vpp = 1600V, DC voltage component Vdc = -400V, development frequency Vf = 2000Hz
The rectangular wave bias of is applied.

The magnet roll 331 has four N poles and four S poles alternately arranged, and each shows a peak value of 1000 gauss.

Next, the feature of the present embodiment, that is, the mechanism of the method for collecting the transfer residual toner on the photosensitive member when the image forming apparatus is stopped during development due to the jam of the transfer paper will be described.

FIG. 20 is a schematic configuration diagram of a process cartridge showing the features of this embodiment. In FIG. 20, the same functions as those in the eighth and ninth embodiments are designated by the same reference numerals.

In the present embodiment, in addition to the normal sequence, a return sequence that is prioritized immediately after clearing a jam is provided.

FIG. 20 shows a state in which a jam has occurred (the transfer sheet is not shown). Hereinafter, the recovery sequence that is prioritized immediately after clearing the jam will be described in detail.

Since the restoration sequence is almost the same as that of the eighth embodiment, only different points will be described.

In the embodiment, the magnet roll 331 has a function of conveying toner between SD.

In the return sequence, the photoconductor 301 starts rotating in the direction of arrow A in the figure, and at the same time the magnet roll 331 is rotated.
Rotates at 440 mm / sec in the direction of arrow E in the figure.
At this time, the developing sleeve 330 is stopped. Therefore, the two-component developer 334 in the developing device 321 is
It is conveyed between SD by the magnet roll 331. The regulation of the toner layer thickness is determined by the rotation speed of the magnet roll 331. The magnet roll 331
The rotation speed of is set so that the toner amount can pass between SD and can sufficiently contact the photoconductor 301. By appropriately setting the magnet roll 331, the toner is not conveyed more than necessary, so that the toner does not leak from the process cartridge in the above sequence.

FIG. 21 shows a state in which the return sequence is being executed.

Developing sleeve 330 and magnet roll 3
The two-component developer 333 carried by 31 is packed in the SD area, and the residual toner 335 carried by the rotation of the photoconductor 301 is collected so as to be scraped off. After the residual toner 335 is sufficiently collected,
Rotate and stop. After the photoconductor 301 is stopped, the developing sleeve 330 and the magnet roll 331 rotate twice at the same rotation speed as in the normal sequence, and the residual toner 335 remains.
The two-component developer 334 containing is collected in the developing device 321. At this point, the collection of the residual toner on the photoconductor 301 is completed.

After the residual toner 335 is collected, the transfer roller 313
Then, the toner removing member 314 returns to the position of the normal sequence. Further, the switch T in the charging bias power source 317 is also switched to the normal sequence (SW1), and the restoration sequence is completed.

In this embodiment, since the microcarriers on the developing sleeve are positively charged in the return sequence, the residual toner on the photoconductor adheres to the microcarriers one after another, so that the residual toner can be steadily collected. it can.
Since the microcarrier has a particle size of 20 μm and has an extremely large surface area as compared with a normal carrier, the recovery capability of the carrier itself is high. Further, since the magnet roll may be rotated only in one direction, the structure becomes easy.

In this example, the A4 portrait image was printed by a single print. During the endurance of 6000 sheets, 10
Jam was intentionally generated about once every 100 sheets, but problems such as backside smearing of the transfer paper by the transfer roller and toner leakage from the improperly charged process cartridge did not occur.

Therefore, even in the non-contact development by the above method, an effective toner collecting method can be realized by bringing the two-component developer into contact with the photosensitive member during the recovery sequence at the time of jam.

[0203]

As is apparent from the above description, according to the present invention, when it is confirmed that a jam has occurred when the power of the main body is turned on, the photosensitive member cleaning sequence takes precedence over the normal sequence. Therefore, even in an image forming apparatus that employs a non-contact developing method and a simple cleaning method that does not have a cleaning container, it is possible to effectively clean the photoconductor after a jam occurs and stabilize an image without fogging or stains. Can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a laser beam printer which is an image forming apparatus according to first to third embodiments of the present invention.

FIG. 2 is a schematic explanatory diagram of each bias switching sequence of the image forming apparatus according to the first exemplary embodiment of the present invention.

FIG. 3 is a schematic explanatory diagram of each bias switching sequence of the image forming apparatus according to the second exemplary embodiment of the present invention.

FIG. 4 is a schematic explanatory diagram of each bias switching sequence of the image forming apparatus according to the third exemplary embodiment of the present invention.

FIG. 5 is a schematic sectional view of a laser beam printer which is an image forming apparatus according to a fourth embodiment of the present invention.

FIG. 6 is a schematic sectional view of a laser beam printer which is an image forming apparatus according to a fourth embodiment of the present invention.

FIG. 7 is a schematic sectional view of a laser beam printer which is an image forming apparatus according to a fifth embodiment of the present invention.

FIG. 8 is a schematic sectional view of a laser beam printer which is an image forming apparatus according to a sixth embodiment of the present invention.

FIG. 9 is a schematic sectional view of a laser beam printer which is an image forming apparatus according to a sixth embodiment of the present invention.

FIG. 10 is an enlarged view of the vicinity of the D blade of the developing device of the image forming apparatus according to the sixth embodiment of the present invention.

FIG. 11 is a schematic sectional view of a laser beam printer which is an image forming apparatus according to a seventh embodiment of the present invention.

FIG. 12 is a schematic sectional view of a laser beam printer which is an image forming apparatus according to a seventh embodiment of the present invention.

FIG. 13 is a schematic sectional view of a laser beam printer which is an image forming apparatus according to a seventh embodiment of the present invention.

FIG. 14 is a schematic sectional view of an image forming apparatus according to an eighth embodiment of the present invention.

FIG. 15 is a schematic sectional view of an essential part of an image forming apparatus according to an eighth embodiment of the present invention.

FIG. 16 is a schematic sectional view of an essential part of an image forming apparatus according to an eighth embodiment of the present invention.

FIG. 17 is a schematic sectional view of an essential part of an image forming apparatus according to a ninth embodiment of the present invention.

FIG. 18 is a schematic sectional view of a main part of an image forming apparatus according to a ninth embodiment of the present invention.

FIG. 19 is a schematic sectional view of a main part of an image forming apparatus according to a tenth embodiment of the present invention.

FIG. 20 is a schematic sectional view of a main part of an image forming apparatus according to a tenth embodiment of the present invention.

FIG. 21 is a schematic sectional view of a main part of an image forming apparatus according to a tenth embodiment of the present invention.

[Explanation of symbols]

 1, 101, 301 Photoreceptor 2, 102, 302 Charging roller 3, 103, 307 Developing device 4, 127, 310, 330 Developing sleeve 5, 313 Transfer roller 6 Cleaning roller 7, 311 Magnet roll 8 D blade 114, 314 Toner Removing member 117 Charging bias application power supply 118 Magnetic toner 131 Magnetic blade 132 Transfer bias application power supply 133 Transfer roller scraper 134 Untransferred toner recovery container 308 Toner 309 Doctor blade 317 Charging bias power supply 319 Residual toner 334 Two-component developer 343 Process cartridge

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Yoshida 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (12)

[Claims] 1. A photosensitive member, a charging device, a developing device in which at least a developer is not in contact with the photosensitive member, a contact transfer device, and a simple means for temporarily collecting transfer residual toner on the photosensitive member. In an image forming apparatus having a cleaning unit or a memory removing unit that disturbs the transfer residual toner, a unit for detecting the occurrence of a jam, a non-volatile memory for storing the occurrence of the jam, and a unit for detecting the occurrence of the jam And a means for transmitting to the non-volatile memory, when the jam occurrence is stored in the non-volatile memory when the power of the main body is turned on, the photoconductor cleaning sequence is executed in preference to the normal sequence, After the photoconductor cleaning sequence is completed, the nonvolatile memory is reset to return to the normal sequence, and the photoconductor cleaning sequence is one transfer paper to photoconductor cleaning paper. And a transfer residual toner held on the photoconductor in the transfer area is transferred to the cleaning sheet and then the cleaning sheet is output to the outside of the apparatus. . 2. The photosensitive member cleaning sequence supplies one transfer sheet as a photosensitive member cleaning sheet to a transfer area and causes the transfer residual toner on the photosensitive element to be held by the contact transfer device. 2. The image forming apparatus according to claim 1, wherein the sequence is such that after the transfer residual toner held in the contact transfer device is transferred to the cleaning sheet, the cleaning sheet is output to the outside of the apparatus. 3. The photosensitive member cleaning sequence supplies one transfer sheet as a photosensitive member cleaning sheet to a transfer area, and causes the transfer residual toner on the photosensitive member to be held by the photosensitive member and the contact transfer device. The transfer residual toner held on the photoconductor in the area is transferred to the surface of the cleaning paper, the transfer residual toner on the contact transfer device is transferred to the back surface of the cleaning paper, and then the cleaning paper is output to the outside of the device. The image forming apparatus according to claim 1, wherein: 4. The image forming apparatus according to claim 1, wherein the contact transfer device is a transfer roller. 5. A photoconductor, a charging device, a developing device in which at least a developer is not in contact with the photoconductor, a contact transfer device, a cleaning unit of the contact transfer device, and a transfer residue on the photoconductor. In an image forming apparatus having a simple cleaning unit for temporarily collecting toner or a memory removing unit for disturbing the transfer residual toner, a unit for detecting the occurrence of a jam, a nonvolatile memory for storing the occurrence of the jam, and , A means for detecting the occurrence of a jam and transmitting it to the non-volatile memory, and when the jam occurrence is stored in the non-volatile memory when the power of the main body is turned on, the normal sequence is prioritized. The photosensitive member cleaning sequence is executed to reset the nonvolatile memory to the normal sequence after the photosensitive member cleaning sequence is completed. Is a sequence in which the transfer residual toner held on the photoconductor is transferred to the contact transfer device, and the cleaning means of the contact transfer device is operated to collect the transfer residual toner on the contact transfer device. The image forming apparatus is characterized in that the cleaning means of the contact transfer device is deactivated during image formation in the sequence of. 6. A photosensitive member, a charging device, a developing device in which at least a developer is not in contact with the photosensitive member, a transfer device, and simple cleaning for temporarily collecting transfer residual toner on the photosensitive member. In the image forming apparatus having the means or the memory removing means for disturbing the transfer residual toner, a means for detecting the occurrence of a jam, a non-volatile memory for storing the occurrence of the jam, and a detecting means for detecting the occurrence of the jam. If a jam occurrence is stored in the non-volatile memory when the power of the main body is turned on, the photoconductor cleaning sequence is executed in preference to the normal sequence, After the body cleaning sequence is completed, the nonvolatile memory is reset to return to the normal sequence, and at least a part of the developer in the developing device is stored during the photoconductor cleaning sequence. Image forming apparatus characterized by contacting the optical body. 7. The photoconductor cleaning sequence, wherein the developing device has a developer carrier rotatably supported and magnetic field generating means fixed inside the developer carrier in a normal sequence. At the start, the magnetic field generating means is moved and fixed in the direction opposite to the rotation direction of the developer carrier, and at the end of the photosensitive member cleaning sequence, the fixed magnetic field generating means is returned to the original position and fixed. The image forming apparatus according to claim 6, which is characterized in that. 8. The developing device has a developer carrier rotatably supported and magnetic field generating means fixed inside the developer carrier, and the developing device is provided during the photoconductor cleaning sequence. The image forming apparatus according to claim 6, wherein the agent carrier is rotated in a direction opposite to that in the normal sequence. 9. The developing device has a developer bearing member rotatably supported and a magnetic field generating means rotatably supported inside the developer bearing member. 7. The image forming apparatus according to claim 6, wherein the number of rotations and the direction of rotation of the developer carrier and the magnetic field generating means are changed with respect to those in the normal sequence. 10. The developing device comprises a developer carrier rotatably supported, a magnetic field generating means fixed inside the developer carrier, and a developer carrier outside the developer carrier. A developer regulating means disposed with a gap between the developer surface and the body surface, and the gap between the developer carrying member and the developer regulating means during the normal sequence is set during the photoconductor cleaning sequence. The image forming apparatus according to claim 6, wherein the image forming apparatus is larger than the above. 11. The developing device comprises a developer bearing member rotatably supported, a magnetic field generating means fixed inside the developer bearing member, and the developer bearing member outside the developer bearing member. 7. The image according to claim 6, further comprising: a developer regulating unit that is brought into contact with the body surface at a predetermined pressure, wherein the pressure is set to be smaller than that in the normal sequence during the photoconductor cleaning sequence. Forming equipment. 12. The developing device has a rotatable developer carrying member which is disposed facing the photoconductor with a gap provided between the developing device and the photoconductor, and the developing device has the rotatable developer carrier during the photoconductor cleaning sequence. 7. The image forming apparatus according to claim 6, wherein the gap is made smaller than that in the normal sequence.