JP2021051286A - Image forming apparatus - Google Patents

Abstract

To provide an image forming apparatus that can effectively cope with jam processing, while increasing minimization of the capacity of a recovered developer box provided in a cartridge.SOLUTION: An image forming apparatus comprises a detection member that detects a conveyance state of a recording medium for recording a developer image. When the detection member detects that the conveyance state of the recording medium is not good, a control unit performs in order a first operation to continue, without stopping, rotation operations of image carriers and an intermediate transfer body, and a second operation to, after the conveyance state is detected to be not good, when the surfaces of the image carriers travel a predetermined distance by the rotation operations of the image carriers, stop the rotation operations of the image carriers. A developer retained on the surfaces of the image carriers is transferred from the image carriers to the intermediate transfer body, and recovered by a cleaning member.SELECTED DRAWING: Figure 5

Description

The present invention relates to an image forming apparatus. In particular, the present invention relates to an electrophotographic image forming apparatus that forms an image on a recording material by using an electrophotographic method.

Conventionally, there is a configuration in which a process cartridge can be attached to and detached from the image forming apparatus main body. Further, the process cartridge also has a configuration including a waste toner box that collects and stores the "transfer residual toner" remaining on the photoconductor drum after transfer and the "fog toner" existing in the non-image portion.

On the other hand, in recent years, there has been a demand for miniaturization and large capacity of process cartridges, and reduction of waste toner box (capacity) of process cartridges has been studied (see Patent Documents 1 and 2).

Specifically, in Patent Document 1, by providing an alumina layer having a volume resistivity higher than that of the rubber layer on the surface of the developing roller, the generation of "fog toner" is reduced, and the waste toner of the process cartridge is reduced accordingly. We are trying to reduce the capacity of the box.

Further, in Patent Document 2, by optimizing the developer and developing process conditions, the amount of waste toner such as "transfer residual toner" and "fog toner" is reduced, and the capacity of the waste toner box of the process cartridge is reduced. ing.

JP 2015-94897 JP 2001-343779

However, there is still room for improvement in the configurations of Patent Documents 1 and 2. Specifically, for example, when the printer paper is clogged (hereinafter referred to as "jam"), a large amount of "(jam) toner" that is transferred to the photoconductor drum without being transferred to the paper is also a process cartridge. It is collected and stored in the waste toner box of. Therefore, in Patent Documents 1 and 2, it is necessary to maintain the capacity of the waste toner box of the process cartridge to some extent in advance in preparation for dealing with a sudden case such as "jam" (jam processing). Therefore, it cannot be said that the miniaturization of the waste toner box provided in the process cartridge is sufficient.

In view of the above problems, it is an object of the present invention to provide an image forming apparatus capable of effectively dealing with jam processing while improving the minimization of the capacity of the recovery developer box provided in the cartridge. ..

The image forming apparatus of the present invention
A rotatable image carrier that supports a developer image developed from an electrostatic latent image on the surface,
A developer carrier that carries a developer supplied to the image carrier for developing the electrostatic latent image and can come into contact with the image carrier.
An exposure member that irradiates and exposes the surface of the image carrier,
An intermediate transfer body that is in contact with the surface of the image carrier, carries the developer image transferred from the image carrier, and can rotate.
A cleaning member that cleans the surface of the intermediate transfer member,
A secondary transfer member that secondarily transfers the developer image from the intermediate transfer body to a recording medium for recording the developer image.
A fixing member for fixing the developer image transferred to the recording medium by the secondary transfer member, and a fixing member.
A detection member that detects the transport state of the recording medium, and
Control unit and
An image forming apparatus equipped with
The control unit
When the detection member detects that the transport state of the recording medium is poor, the first operation of continuing the rotational operation of the image carrier and the intermediate transfer body without stopping the image carrier and the intermediate transfer body.
After the defect is detected, when the surface of the image carrier moves a predetermined distance by the rotation operation of the image carrier, the second operation of stopping the rotation operation of the image carrier is performed in order. ,
In the first operation,
The fixing operation of the fixing member is stopped,
The predetermined distance is
It is equal to or longer than the length of the surface of the image carrier in the rotation direction of the image carrier from the developing position in contact with the developer carrier to the transfer position in contact with the intermediate transfer body.
Moreover, the distance from the secondary transfer position on the secondary transfer member to the fixing position on the fixing member within the period in which the recording medium moves is less than or equal to the distance the surface of the image carrier has moved. And.

According to the image forming apparatus of the present invention, it is possible to effectively deal with jam processing while improving the minimization of the capacity of the recovery developer box provided in the cartridge.

Cross-sectional conceptual diagram of the image forming apparatus according to the first embodiment of the present invention. A control block diagram of the image forming apparatus according to the first embodiment of the present invention. (A) Conceptual diagram of a cross section of a process cartridge used in the image forming apparatus according to the first embodiment of the present invention; (b) Conceptual diagram showing a contact position and a separation position in the process cartridge; (c) A predetermined distance L is shown. Schematic diagram; (d) Schematic diagram showing the maximum value of a predetermined distance L Flow chart relating to control at the time of jam (occurrence) in the image forming apparatus according to the first embodiment of the present invention. (A) (b) Schematic diagram showing the transfer state of the developer in the image forming apparatus according to Example 1 and Comparative Example of the present invention. Flow chart regarding control at the time of jam (return) in the image forming apparatus according to the second embodiment of the present invention. (A) (b) Schematic diagram showing the transfer state of the developer in the image forming apparatus according to Example 2 and Reference Example (Example 1) of the present invention. Flow chart regarding control at the time of jam (occurrence) in the image forming apparatus according to the third embodiment of the present invention.

Hereinafter, the electrophotographic image forming apparatus according to the present invention will be described with reference to the drawings. The examples described below exemplify the present invention, and the dimensions, materials, shapes, relative positional relationships, and the like of the components described below are particularly specific. Unless not, the scope of the invention is not limited thereto.

Here, the electrophotographic image forming apparatus is an device that forms an image on a recording medium by using an electrophotographic image forming method. Examples of the electrophotographic image forming apparatus include, for example, an electrophotographic copying machine, an electrophotographic printer (for example, a laser beam printer, an LED printer, etc.), a facsimile machine, a word processor, and the like.

Further, the process cartridge forming a part of the image forming apparatus is obtained by integrally forming a charging means, a developing means or a cleaning means and an electrophotographic photosensitive member drum into a cartridge, and this cartridge is used for the main body of the electrophotographic image forming apparatus. It is removable. Further, at least one of the charging means, the developing means, and the cleaning means and the electrophotographic photosensitive member drum are integrally formed into a cartridge so that they can be attached to and detached from the main body of the electrophotographic image forming apparatus. Further, at least the developing means and the electrophotographic photosensitive member drum are integrally formed into a cartridge so that they can be attached to and detached from the main body of the electrophotographic image forming apparatus.

Hereinafter, the configuration of the electrophotographic image forming apparatus (hereinafter, image forming apparatus) according to an example (hereinafter, referred to as the present embodiment) of the present invention and the image forming process will be described with reference to the drawings.

Hereinafter, the overall configuration of the image forming apparatus, the configuration of the process cartridge, and the characteristic configuration of the invention in the first embodiment of the present invention will be described with reference to FIGS. 1 to 5.

[Overall configuration of image forming apparatus]
Hereinafter, the overall configuration of an embodiment of the electrophotographic image forming apparatus (image forming apparatus) of the present invention will be described.

FIG. 1 is a conceptual cross-sectional view of an image forming apparatus according to a first embodiment of the present invention.

As shown in FIG. 1, the image forming apparatus 100 of the present invention is a full-color laser beam printer that employs an intermediate transfer method. The image forming apparatus 100 can form a full-color image by using the toner (developer) 80 on the recording material 35 (for example, recording paper, plastic sheet, cloth, etc.) according to the image information. The image information is input to the image forming apparatus main body from a host device such as an image reading device connected to the image forming apparatus main body 100A or a personal computer communicably connected to the image forming apparatus main body.

In the image forming apparatus 100, the process cartridges 7 as a plurality of image forming units form SY and SM for forming images of each color of yellow (Y), magenta (M), cyan (C), and black (K), respectively. , SC, SK.

The process cartridge 7 can be attached to and detached from the image forming apparatus 100 via mounting means such as a mounting guide and a positioning member provided on the image forming apparatus main body. In this embodiment, the process cartridges 7 for each color all have the same shape, and the process cartridges 7 for each color contain yellow (Y), magenta (M), cyan (C), and black (K), respectively. ), The toner (developer) 80 of each color is stored.

An exposure device 30 (exposure member) including a scanner unit is arranged around the photoconductor drum 1 (image carrier). The exposure apparatus 30 irradiates a laser based on the image information to form an electrostatic image (electrostatic latent image T0) on the photoconductor drum 1. The laser exposure is written out from a position signal in the polygon scanner called BD for each scanning line in the main scanning direction (direction orthogonal to the sheet material conveying direction). On the other hand, in the sub-scanning direction (conveyance direction of the sheet material), the TOP signal starting from the switch (not shown) in the sheet material transfer path is delayed by a predetermined time. As a result, laser exposure can always be performed on the same position (exposure position Y1) on the photoconductor drum 1 at the four process stations Y, M, C, and Bk.

An intermediate transfer belt 31 as an intermediate transfer body for transferring the toner image (developer image T1) on the photoconductor drum 1 to the recording material 35 is arranged so as to face the four photoconductor drums 1. The intermediate transfer belt 31 formed of the endless belt as the intermediate transfer body abuts on all the photoconductor drums 1 and circulates (rotates) in the direction of arrow B (counterclockwise) in the drawing. The contact position between the photoconductor drum 1 and the intermediate transfer belt 31 is the transfer position Y2, which will be described later.

On the inner peripheral surface side of the intermediate transfer belt 31, four primary transfer rollers 32 as primary transfer means are arranged side by side so as to face the photoconductor drums 1 (a to d). Then, a bias having a polarity opposite to the normal charging polarity of the toner is applied to the primary transfer roller 32 from a primary transfer bias power supply (high voltage power supply) as a primary transfer bias applying means (not shown). As a result, the toner image on the photoconductor drum 1 is transferred (primary transfer) on the outer peripheral surface 31a of the intermediate transfer belt 31 (intermediate transfer body) at the transfer position Y2.

Further, a secondary transfer roller 33 as a secondary transfer means is arranged on the outer peripheral surface side of the intermediate transfer belt 31. Then, a bias having a polarity opposite to the normal charging polarity of the toner is applied to the secondary transfer roller 33 from a secondary transfer bias power supply (high pressure power supply) as a secondary transfer bias applying means (not shown). As a result, the toner image on the intermediate transfer belt 31 is transferred (secondary transfer) to the recording material 35. For example, at the time of forming a full-color image, the above-mentioned process is sequentially performed in the image forming units SY, SM, SC, and SK, and the toner images of each color are sequentially superimposed on the intermediate transfer belt 31 and primary transferred.

The image forming apparatus 100 includes a pickup roller 144, a transport roller 148, and a resist roller 160 as transport means for transporting the recording material 35 to the secondary transfer unit. The recording material 35 is fed by the pickup roller 144 at a predetermined timing from the start of exposure. After that, the paper is transported by the transport roller 148 and the resist roller 160, and when the tip of the recording material 35 is detected by the paper detection sensor 161, the transport roller 148 and the resist roller 160 are temporarily stopped and put into a standby state. Then, at a predetermined timing, the driving of the transport roller 148 and the resist roller 160 is restarted. Then, the recording material 35 in the standby state starts to move and is conveyed toward the secondary transfer unit. The paper detection sensor 161 is connected to a "detection member D" described later, and can output a signal to the detection member D.

By executing the feeding and re-feeding at a predetermined timing from the start of exposure, the toner image on the intermediate transfer belt 31 overlaps with the recording material 35 at the secondary transfer portion, so that the recording material The toner image is secondarily transferred onto the 35 without misalignment.

The recording material 35 to which the toner image is transferred is conveyed to a fixing device (fixing member) 34 as a fixing means. By applying heat and pressure to the recording material 35 in the fixing device 34, the toner image is fixed to the recording material 35.

The transfer residual toner remaining on the intermediate transfer belt 31 after the secondary transfer is recovered by the cleaning member 11A of the intermediate transfer belt and is housed in the recovery toner box 11B (recovery developer box).

[Control system of image forming apparatus]
Next, the control system of the image forming apparatus will be described.

FIG. 2 is a control block diagram of the image forming apparatus according to the first embodiment of the present invention.

As shown in FIG. 2, all the processes of the image forming apparatus are collectively controlled by the system controller 901. The system controller 901 (control unit) mainly plays a role of driving each load in the image forming apparatus, collecting and analyzing information of sensors, and exchanging data with the display unit 906, that is, a user interface. The system controller 901 is equipped with a CPU 903 to play that role. The CPU 903 also executes various sequences related to predetermined image formation by a program stored in the ROM 904 mounted on the system controller 901. At that time, a RAM 905 is also installed to store data that needs to be temporarily or permanently stored. The RAM 905 stores high-voltage set values for the high-voltage control unit 908, various data, image formation command information from the display unit 906, and the like.

The system controller 901 obtains information such as printing conditions and density setting values set by the user from the display unit 906. On the other hand, the system controller 901 sends data to the display unit 906 to indicate to the user the state of the image forming apparatus, for example, the number of images formed, information on whether or not an image is being formed, the occurrence of jam and its location, and the like. ing.

In this image forming apparatus, a plurality of motors, DC loads such as clutches / solenoids, and sensors such as photo interrupters are arranged in various places inside the apparatus. That is, by driving the motor and each DC load as appropriate, the recording medium is conveyed and each unit is driven, and various sensors monitor the operation.

Therefore, the system controller 901 detects signals from various sensors by the sensor input unit 911, and controls the stop and drive of each motor by the motor control unit 909 based on the signals. The 909 also controls the contact separation between the intermediate transfer belt 31 and the photoconductor drum, and the contact separation operation between the developing roller and the photoconductor drum.

At the same time, the DC load control unit 910 operates the clutch / solenoid to smoothly advance the image forming operation. Further, by sending various high-voltage control signals to the high-voltage control unit 908, an appropriate high voltage is applied to the charging roller, the developing roller, the primary transfer roller, the secondary transfer roller, and the like constituting the high-voltage unit 914.

Further, the fixing device 34 has a built-in fixing heater 915 as a heating body, and is ON / OFF controlled by the AC driver 912. At this time, the fixing heater 915 is provided with a thermistor 913 as a temperature detector for measuring the temperature. Then, the A / D converter 907 converts the resistance value change of the thermistor 913 in response to the temperature change of the fixing heater into a voltage value, and then inputs the digital value to the system controller 901. The above-mentioned AC driver 912 is controlled based on this temperature data.

[Process cartridge configuration]
Next, the overall configuration of the process cartridge 7 mounted on the image forming apparatus 100 of this embodiment will be described with reference to FIG.

FIG. 3A is a conceptual diagram of a cross section of a process cartridge used in the image forming apparatus according to the first embodiment of the present invention, and FIG. 3B is a concept showing a contact position and a separation position in the process cartridge. It is a figure. Further, FIG. 3C is a schematic diagram showing a predetermined distance L, and FIG. 3D is a schematic diagram showing a maximum value of the predetermined distance L. In this embodiment, the type (color) of the toner contained is shown. ), The configuration and operation of the process cartridge 7 for each color are substantially the same.

FIG. 3A shows the process cartridge 7 viewed along the longitudinal direction (rotational axis direction) of the photoconductor drum 1. The process cartridge 7 shown in FIG. 3A is in a posture of being mounted on the image forming apparatus main body. Hereinafter, when describing the positional relationship, direction, etc. of each member of the process cartridge, the positional relationship, direction, etc. in the posture shown in FIG. 3 are shown.

In this embodiment, the process cartridge 7 integrates a photoconductor unit 13 including a photoconductor drum 1 (image carrier) and a developing unit 4 provided with a developing roller 17 (developer carrier) and the like. It is composed.

The photoconductor unit 13 has a cleaning frame body (first frame body) 13a as a frame body that supports various elements in the photoconductor unit 13. A photoconductor drum 1 is rotatably attached to the cleaning frame body 13a via a bearing (not shown). The photoconductor drum 1 is rotationally driven in the direction of arrow A (clockwise) according to the image forming operation by transmitting the driving force of a drive motor as a driving means (driving source) (not shown) to the photoconductor unit 13. Will be done.

In this embodiment, the photoconductor drum 1, which is the center of the image forming process, is (organic) photosensitive in which an undercoat layer, a carrier generation layer, and a carrier transfer layer, which are functional films, are sequentially coated on the outer peripheral surface of an aluminum cylinder. The body drum 1 is used.

Further, in the photoconductor unit 13, a cleaning member 6 (second cleaning member) and a charging roller 2 are arranged so as to come into contact with the peripheral surface of the photoconductor drum 1. The transfer residual toner removed from the surface of the photoconductor drum 1 by the cleaning member 6 is dropped and stored in the recovery toner box (recovery developer chamber) 14 formed inside the cleaning frame 13a.

The charging roller 2, which is a charging means, rotates drivenly by bringing the roller portion of the conductive rubber into pressure contact with the photoconductor drum 1.

Here, a predetermined DC voltage is applied to the photoconductor drum 1 as a charging process to the core metal of the charging roller 2, whereby a uniform dark potential (a uniform dark potential) is applied to the surface of the photoconductor drum 1. Vd) is formed. The spot pattern of the laser beam emitted in response to the image data by the laser beam from the exposure apparatus 30 described above exposes the photoconductor drum 1, and the exposed portion is charged by the carriers from the carrier generation layer. Disappears and the potential drops. As a result, an electrostatic latent image having a predetermined bright area potential (Vl) in the exposed area and a predetermined dark area potential (Vd) in the unexposed area is formed on the photoconductor drum 1. In this example, Vd = −500V and Vl = −100V.

On the other hand, the developing unit 4 includes a frame body (second frame body) 4a, a developing roller 17 as a developing agent carrier for supporting the toner 80, and a toner as a supply member for supplying toner to the developing roller 17. It has a developing chamber 18a in which a supply roller 20 is arranged. Further, the frame (second frame) 4a of the developing unit 4 has a toner accommodating chamber (developer accommodating chamber) 18b for accommodating toner, and the toner accommodating chamber 18b is in the direction of gravity with respect to the toner supply roller 20. It is located below. The developing chamber 18a and the toner accommodating chamber 18b are formed by partitioning the internal space of the frame body 4a by a partition portion 18c, but are communicated with each other by an opening 18d.

Further, the toner supply roller 20 forms a toner nip portion N (a portion sandwiching the toner between the developing roller 17 and the toner supply roller 20) between the developing roller 17 and rotating.

A stirring and transporting member 22 is provided in the toner accommodating chamber 18c. The stirring and transporting member 22 is also for stirring the toner stored in the toner storage chamber 18c and for transporting the toner toward the upper part of the toner supply roller 20 in the direction of arrow G in the drawing.

The developing blade 21 is arranged below the developing roller 17 and is in contact with the developing roller at a counter, and regulates the coating amount of the toner supplied by the toner supply roller 20 and applies an electric charge. In this embodiment, a leaf spring-shaped thin plate made of SUS having a thickness of 0.1 mm is used as the developing blade 21, and a contact pressure is formed by utilizing the spring elasticity of the thin plate, and the surface thereof is a toner and a developing roller 17. Is in contact with. Here, the developing blade is not limited to this, and a thin metal plate such as phosphor bronze or aluminum may be used. Further, the surface of the developing blade 21 may be coated with a thin film such as a polyamide elastomer, urethane rubber or urethane resin.

The toner is triboelectrically charged by rubbing between the developing blade 21 and the developing roller 17, and is charged, and at the same time, the layer thickness is regulated. Further, in this embodiment, a predetermined voltage is applied to the developing blade 21 from a blade bias power supply (not shown) to stabilize the toner coating. In this example, V = −500V was applied as the blade bias.

The developing roller 17 and the photoconductor drum 1 rotate so that their surfaces move in the same direction (in this embodiment, from the bottom to the top) at the facing portions.

In this embodiment, the developing roller 17 is arranged in contact with the photoconductor drum 1, but the developing roller 17 is arranged close to the photoconductor drum 1 at a predetermined interval. You may.

In this embodiment, the toner negatively charged by triboelectric charging with respect to the predetermined DC bias applied to the developing roller 17 is subjected to the potential difference in the developing unit (development position Y3) in contact with the photoconductor drum 1. , Transfers only to the bright potential part and visualizes the electrostatic latent image. In this embodiment, by applying V = −300V to the developing roller, a potential difference ΔV = 200V from the bright potential portion was formed, and a toner image was formed.

The toner supply roller 20 is an elastic sponge roller having a foam layer formed on the outer periphery of the conductive core metal. The toner supply roller 20 and the developing roller 17 are in contact with each other with a predetermined amount of penetration, that is, in FIG. 3, the toner supply roller 20 has a recessed amount ΔE formed into a concave shape by the developing roller 17. The toner supply roller 20 and the developing roller 17 rotate in the nip portion N in opposite directions with a peripheral speed difference, and by this operation, the toner supply roller 20 supplies toner to the developing roller 17. ..

[Operation at the time of jam (occurrence)]
Next, the operation (control) of the recording medium when a jam occurs in this embodiment will be described with reference to FIG.

FIG. 4 is a flowchart relating to control at the time of jam (generation) in the image forming apparatus according to the first embodiment of the present invention.

First, the image forming apparatus 100 of this embodiment includes a fixing motor (not shown) that rotates the fixing roller 170 of the fixing device 34, and a belt motor (not shown) that rotationally drives the intermediate transfer belt 31. Further, the image forming apparatus 100 is also provided with a cartridge driving motor (not shown) capable of independently rotating and driving the photoconductor unit and the developing unit in the process cartridge 7.

The system controller 901 (control unit) can control the drive and stop of these motors by sending a control signal to the motor control unit 909. Further, the system controller 901 inputs signals output from various sensors such as the fixed paper discharge sensor 171 and the paper detection sensor 161 to the detection member D via the sensor input unit 911, and causes a “conveyance failure (jam)”. It is being detected. That is, the system controller 901 is provided with a "transport defect detecting means (detection member D)" that can detect (identify) a jam occurrence location of the image forming apparatus.

During image formation, the system controller 901 constantly monitors for jams.

As shown in FIG. 4, in this embodiment, when the system controller 901 (detection member D) detects the occurrence of jam during the image forming operation in step S1 (jam detection step), the system controller 901 proceeds to step S2.

In step S2, the system controller 901 (control unit) first stops the exposure operation by the exposure device 30. At the same time, the rotational drive of the process cartridge 7, the intermediate transfer belt 31, and the secondary transfer roller 33 is not stopped and continues for a predetermined period.

The predetermined (continuation) period is approximately a distance corresponding to a predetermined distance L (on the moving path of the electrostatic latent image / toner image) from the exposed portion (exposure position Y1) to the transfer portion (transfer position Y2). It corresponds to d1 (d1 = 45 mm in this embodiment). In other words, this predetermined (continuation) period is the time required to move (rotate) the surface of the photoconductor drum to a predetermined distance L.

Then, when a predetermined period (predetermined distance L) has elapsed (moved) after detecting the occurrence of jam, the system controller 901 stops the image forming operation of the image forming apparatus 100 (step S3). Specifically, in step S3, the operations (related to image formation) of the process cartridge 7, the intermediate transfer belt 31, and the secondary transfer roller 33 included in the image forming apparatus 100 are stopped.

In step S2, the fixing operation of the fixing device 34 (fixing member) may cause a so-called "wrapping jam" in which the paper is wound around the fixing roller. In order to prevent such a problem, the fixing operation of the fixing device 34 may be stopped in advance in the step S2 after the jam is detected in the jam detecting step (step S1).

Next, with reference to FIG. 5, the transfer state of the developer by the post-jam treatment (operation in step S2) of this embodiment will be described.

As a comparative example, a case where the image forming operation of the image forming apparatus is immediately stopped after the jam occurs without performing step S2 (first operation) will be described while comparing with the case of this embodiment.

FIG. 5A is a schematic view showing a transfer state of the developer in the image forming apparatus according to the first embodiment of the present invention. FIG. 5B is a schematic view showing a transition state of the developer in the comparative example.

Specifically, FIGS. 5A and 5B show the status of the developer adhering (retaining) to each member at the third station (cyan) and the fourth station (black) of the image forming apparatus 100. There is.

As shown in FIG. 5B, in the comparative example, when a jam occurs (detected), the immediate drive stop and various biases can be switched to OFF (the image formation operation is stopped), so that the photoconductor drum is developed. The (transferred) (jam) toner H remains as it is.

That is, in the case of the comparative example, when the toner H on the photoconductor drum is not processed (recovered) immediately after the jam, the electric charge held by the toner H (due to triboelectric charging) is attenuated. Therefore, during the jam recovery operation, it becomes difficult to transfer (move) the toner H on the photoconductor drum again, and the toner H must be collected in the recovery toner box 14 of the process cartridge. Therefore, in the case of the comparative example, the jam toner H on the photoconductor drum cannot be transferred onto the intermediate transfer belt 31 and recovered by the cleaning device (recovery toner box 11B) of the intermediate transfer belt.

On the other hand, in this embodiment, as shown in FIG. 5A, when the occurrence of jam is detected, the driving of the photoconductor drum is not stopped, and the toner developed (transferred) to the photoconductor drum is transferred to the intermediate transfer belt 31. It can be stopped after it has been completely transferred (transferred) to. Therefore, during the jam recovery operation, the toner H on the photosensitive drum has already been moved to the intermediate transfer belt, so that the recovery toner box 14 of the process cartridge 7 collects a large amount of jam toner H on the photoconductor drum when jam occurs. There is no need to do it.

More specifically, in this embodiment, the exposure operation is stopped after the occurrence of jam is detected. Then, (distance d2 from the developing unit (development position Y3) to the transfer unit (transfer position Y2)) + (distance d3 from the exposure unit (exposure position Y1) to the development unit (development position Y3)) (note that d1 = D2 + d3), the image forming operation (driving) was extended (continued).

As a result, in step S2, the developer (jam toner H) corresponding to the latent image portion (charged on the developing roller) that was not developed (transferred) on the photoconductor drum when the jam occurred was applied to the photoconductor drum 1. Can be sufficiently developed (transferred). Moreover, the developer can be further transferred (transferred) from the photoconductor drum 1 onto the intermediate transfer belt 31.

Therefore, it is possible to avoid the need to collect the developer (jam toner H) in the recovery toner box 14 of the process cartridge during the jam recovery operation. That is, it is not necessary to reserve the volume for collecting the jam toner H in the process cartridge 7 in advance, the jam processing can be effectively performed, and the volume of the recovered toner box of the process cartridge 7 can be minimized. ..

In step S2 of this embodiment, the driving operation (image forming operation) of the process cartridge 7, the intermediate transfer belt 31, and the secondary transfer roller 33 is continued for the above-mentioned "predetermined distance L". ing. Further, as described above, the predetermined distance L corresponds to the distance d1 (= d2 + d3) from the exposed portion (exposure position Y1) to the transfer portion (transfer position Y2). In this embodiment, when the step S2 is executed, the operation of the fixing roller 170 is stopped.

As a result, even when the fixing roller wrapping jam as described above occurs, further deterioration of wrapping can be effectively prevented. Therefore, the recovery amount (capacity) of the process cartridge 7 to the recovery toner box 14 can be minimized, and the deterioration of the jam caused by the fixing roller can be suppressed. In that case, the recording material 35 conveyed in the image forming apparatus may be gently bent, but it does not affect the jam processing or the like.

Next, immediately after the occurrence (detection) of the jam, the upper limit of the predetermined distance L is examined in the state where the operation of the fixing roller 170 of the image forming apparatus is stopped in step S2. For example, as an experimental example, when the predetermined distance L is set so as to exceed the distance d4 (d4 = 120 mm in this embodiment) from the secondary transfer position Y5 to the fixing position Y4, the following phenomenon may occur. That is, due to the bending of the recording material 35, there is a high possibility that the unfixed toners (regions) of the images on one (same) recording material will "contact" with each other, and as a result, the occurrence of jam causes the user It may cause further discomfort.

More specifically, in step S2, the image forming operation is performed after jam detection at a distance greater than or equal to the distance between the nip of the fixing roller 170 (fixing position Y4) and the nip of the secondary transfer roller 33 (secondary transfer position Y5). If it is continued, the above-mentioned "contact" phenomenon is likely to occur. From this point of view, the upper limit (max) of the "predetermined distance (L)" in step S2 is set so as not to exceed the distance d4 from the "secondary transfer position Y5" to the "fixing position Y4" (d4 ≧ L). be able to.

That is, in this embodiment, the predetermined distance (L) is
Photoreceptor drum from the exposure position (Y1) on the surface 1y of the photoconductor drum 1 (image carrier) by the exposure apparatus 30 (exposure member) to the transfer position (Y2) in contact with the intermediate transfer belt 31 (intermediate transfer body). It is equal to or longer than the length of the surface 1y of the photoconductor drum 1 in the rotation direction A of 1.
The photoconductor is in the period in which the recording medium moves from the secondary transfer position (Y5) on the secondary transfer roller 33 (secondary transfer member) to the fixing position (Y4) on the fixing device 34 (fixing member). It is equal to or less than the distance traveled by the surface 1y of the drum 1.

By setting the predetermined distance within the above range, it is possible to effectively deal with jam processing while improving the minimization of the capacity of the recovery developer box provided in the cartridge. In particular, the discomfort given to the user due to the occurrence of jam can be effectively reduced.

Further, in the present embodiment shown in FIG. 5A, the transfer bias is not applied while the photoconductor drum and the intermediate transfer belt 31 are in contact with each other when the operation at the time of jam recovery is performed. A transfer bias may be applied in order to reduce the amount of toner transferred to the photoconductor drum on the transfer belt.

(Modified Example 1)
Further, in this embodiment, an example is shown in which the system controller 901 (detection member D) stops the exposure operation by the laser after jam detection (step S1) and continuously continues the image formation operation (step S2). However, as one modification, after the jam is detected (step S1), the image forming operation may be temporarily stopped (step S21), and immediately after that, the control shown in this embodiment (step S2) may be performed. That is, a new step of "pause (S21)" and "restart (S22)" may be added between step S1 and step S2 shown in FIG.

Even in this case, the image forming operation is stopped again after step S2 (step S3).

That is, when the detection member D of the control unit (901) detects that the transport state of the recording medium is defective, the first operation (S2) and the second operation (S3) are sequentially performed. Here, in the first operation (S2), the rotation operation of the image carrier and the intermediate transfer body is temporarily stopped (step S21), and then the rotation operation of the image carrier and the intermediate transfer body is restarted (step S22).

Then, in the second operation (S3), after the rotation operation of the image carrier and the intermediate transfer body is restarted (S22), when the surface of the image carrier moves a predetermined distance by the rotation operation of the image carrier, The rotation operation of the image carrier is stopped.

As described above, according to the image forming apparatus of the present embodiment, it is possible to effectively deal with jam processing while improving the minimization of the capacity of the recovery developer box provided in the cartridge. That is, it is possible to provide an image forming apparatus in which the recovery amount of the process cartridge with respect to the recovery toner box 14 is minimized even when a jam occurs.

Further, in this embodiment, the processing after jam detection is controlled by using the "predetermined distance L". For example, a predetermined distance corresponding to the predetermined distance L according to the rotation speed of the image carrier or the intermediate transfer body. Control may be performed at time t.

In the second embodiment, another embodiment relating to the operation (control) when returning from the jam will be described using the image forming apparatus 100 (shown in FIG. 1) similar to the above-described first embodiment.

[Operation when returning from jam]
The operation of the recording medium after the jam is restored in this embodiment will be described with reference to FIGS. 6 and 7.

Note that FIG. 6 is a flowchart relating to control at the time of jam (return) in the image forming apparatus according to the second embodiment of the present invention.

As shown in FIG. 6, during the image forming operation, the system controller 901 detects the occurrence of jam (see step S1), performs the initial operation (see steps S2 and S3), and then determines whether or not the jam has been restored. Is constantly monitored (step A1).

In step A1, the system controller 901 detects that the paper has been removed by, for example, the paper detection sensor 161 (detection member D), and determines that the jam has been restored.

Specifically, in step A1, the operations of steps S2 and S3 described above are executed, and the state "after the jam is restored" that the paper is removed from the jam portion is detected.

Then, after detecting "after the jam is restored", the transfer member and the photoconductor drum are changed from the contact state to the separated state (step A2).

Next, the photoconductor drum and the intermediate transfer belt 31 are rotationally driven at a predetermined distance L (or a predetermined time t), and the toner on the intermediate transfer belt 31 is collected by the intermediate transfer belt cleaning device 11 (11A, 11B). (Step A3)
After that, the operation of the image forming apparatus is finally stopped (step A4).

In step A2, the transfer-photoreceptor drum is not separated from each other, and the intermediate transfer belt 31 and the photoconductor drum 1 are kept in contact with each other when the jam is restored. The difference from the above will be described with reference to FIG. 7.

FIG. 7A is a schematic view showing a transfer state of the developer in the image forming apparatus according to the second embodiment of the present invention. FIG. 7B is a schematic view showing a transition state of the developer in Example 1 as a reference example.

As described above, in the first embodiment, the (jam) toner H transferred from the upstream station (photoreceptor drum 1c) onto the intermediate transfer belt at the time of jam recovery remains as it is. If the treatment is not performed immediately after the jam, the triboelectric charge held by the toner H on the intermediate transfer belt is attenuated. Therefore, in the state where the intermediate transfer belt and the photoconductor drum are in contact with each other during the jam recovery operation, the jam toner H may be re-transferred to the photoconductor drum. Specifically, even if a transfer bias is applied, there is a possibility that the jam toner H on the intermediate transfer belt may be re-transferred to the photoconductor drum (1d) in a small amount at the downstream station (photoreceptor drum 1d).

In the second embodiment, the photoconductor drum and the intermediate transfer belt 31 are physically separated from each other when the jam is restored. Therefore, the possibility as in the first embodiment disappears. As a result, the toner transferred (transferred) from the intermediate transfer belt is not recovered in the recovery toner box 14 (recovery developer chamber) of the process cartridge during the jam recovery process. Therefore, as compared with Example 1, Example 2 can be said to be more advantageous in minimizing the volume of the recovered toner box of the process cartridge.

In this embodiment, as in the case of the first embodiment, it is possible to effectively cope with the jam treatment while improving the minimization of the capacity of the recovery developer box provided in the cartridge.

In this embodiment, another embodiment relating to motion control at the time of jam occurrence will be described using the same image forming apparatus 100 (shown in FIG. 1) as in Example 1 described above.

[Operation when jam occurs]
The operation (control) of the recording medium when a jam occurs in this embodiment will be described with reference to FIG. FIG. 8 is a flowchart relating to control at the time of jam (generation) in the image forming apparatus according to the third embodiment of the present invention.

In this embodiment, in step B1, the system controller 901 constantly monitors whether or not a jam has occurred during image formation.

Then, when the system controller 901 (detection member D) detects the occurrence of jam, the developing roller and the photoconductor drum are separated from each other (step B2).

Next, the system controller 901 rotationally drives the photoconductor drum and the intermediate transfer belt by a predetermined distance L (or a predetermined time t) to transfer the toner on the photoconductor drum to the intermediate transfer belt (step B3). In this embodiment, the predetermined distance L corresponds to the distance d2 (d2 = 25 mm) from the development position Y3 to the transfer position Y2.

After that, the operation of the image forming apparatus is stopped (step B4).

Compared with the first embodiment, this embodiment has an effect of further reducing the toner consumption due to the operation at the time of jam occurrence corresponding to the distance from the exposed portion (exposure position Y1) to the developing position (Y3).

That is, in this embodiment, the predetermined distance (L) is
Photoreceptor drum 1 in the rotation direction A of the photoconductor drum 1 from the development position (Y3) in contact with the developing roller 17 (developer carrier) to the transfer position (Y2) in contact with the intermediate transfer belt 31 (intermediate transfer body). Is longer than the length of 1y on the surface of
The photoconductor is in the period in which the recording medium moves from the secondary transfer position (Y5) on the secondary transfer roller 33 (secondary transfer member) to the fixing position (Y4) on the fixing device 34 (fixing member). It is equal to or less than the distance traveled by the surface 1y of the drum 1.

By setting the predetermined distance (L) within the above range, it is possible to effectively deal with jam processing while improving the minimization of the capacity of the recovery developer box provided in the cartridge. In particular, the discomfort given to the user due to the occurrence of jam can be effectively reduced.

[Other Embodiments]
The present invention is also applicable to a configuration in which the process cartridge is not provided with the cleaning member 6 and the recovery toner box 14, and the transfer residual toner or the fog toner comes into contact with the charging roller 2 during image formation.

Further, by performing the control shown in Examples 1 to 3 of the present invention, it is possible to reduce the amount of contact of the toner with the charging roller 2 generated when jam occurs. As a result, it is possible to obtain effects such as suppressing toner stains on the charging roller 2 and omitting control for removing toner on the charging roller 2.

The configuration of the present invention can be summarized as follows.

The image forming apparatus 100 of the present invention includes an image carrier (photoreceptor drum 1), a developer carrier (development roller 17), an exposure member (exposure apparatus 30), and an intermediate transfer body (intermediate transfer belt 31). A cleaning member 11A for cleaning the surface 31a of the intermediate transfer body is provided. The developer carrier can carry the developer supplied to the image carrier for developing the electrostatic latent image and can come into contact with the image carrier. Further, the exposure apparatus irradiates and exposes the surface of the image carrier.

Further, the image forming apparatus 100 provides a secondary transfer member (secondary transfer roller 33) for secondary transfer of the developer image from the intermediate transfer body to a recording medium (recording material 35) for recording the developer image T1. Have. Then, the image forming apparatus 100 has a fixing member (fixing device 34) for fixing the developer image transferred to the recording medium by the secondary transfer member. Further, the image forming member 100 also includes a detecting member D for detecting the conveyed state of the recording medium and a control unit (system controller 901).

The image carrier supports the developer image T1 developed from the electrostatic latent image T0 on the surface 1y and is rotatable. Further, the intermediate transfer body 31 is in contact with the surface 1y of the image carrier, carries the developer image T1 transferred from the image carrier, and is rotatable.

When the detection member D detects that the transport state of the recording medium is defective, the control unit causes the first operation (S2) and the second operation (S3) to be performed in order, and stays on the surface of the image carrier. The developed developer (jam toner H) is transferred from the image carrier to the intermediate transfer body. In the first operation (S2), the rotation operation of the image carrier and the intermediate transfer body is continued without being stopped. Further, in the second operation (S3), when the surface of the image carrier moves a predetermined distance (L) by the rotation operation of the image carrier after the defect of the transport state is detected, the rotation operation of the image carrier To stop.

Then, in the first operation, the fixing operation of the fixing member is stopped.

The predetermined distance is equal to or greater than the length of the surface of the image carrier in the rotation direction of the image carrier from the development position (Y3) in contact with the developer carrier to the transfer position (Y2) in contact with the intermediate transfer body.
Moreover, it is equal to or less than the distance moved by the surface of the image carrier within the period in which the recording medium moves from the secondary transfer position (Y5) in the secondary transfer member to the fixing position (Y4) in the fixing member.

As a result, when jam occurs, the jam toner remaining on the surface of the image carrier can be efficiently transferred to the intermediate transfer body, and as a result, the volume for the recovered toner of the process cartridge can be reduced. .. That is, it is possible to handle jam processing while minimizing the capacity of the process cartridge. In particular, it is possible to reduce the amount of paper wrapped around the fixing member during jamming.

Further, in the image forming apparatus of the present invention, the predetermined distance (L) is set to be equal to or longer than the length of the surface of the image carrier in the rotation direction of the image carrier from the exposure position (Y1) to the transfer position (Y2). be able to.

In particular, the length of the surface of the image carrier in the rotation direction A of the image carrier from the exposure position Y1 on the surface of the image carrier by the exposure member to the transfer position Y2 in contact with the intermediate transfer member at a predetermined distance (L). It may be (d1).

By setting the predetermined distance (L) to the length d1 or longer, the toner (jam toner) embedded in the latent image formed by the exposed member can be moved to the intermediate transfer body without omission until just before the jam. it can.

Further, in the image forming apparatus of the present invention, the developer carrier (development roller 17) can be moved to a first position Z1 capable of contacting the image carrier and a second position Z2 capable of being separated from the image carrier. It may be configured as follows. The control unit can move the developer carrier from the first position to the second position in the first operation (S2).

As a result, it is possible to reduce the transfer of (jam) toner from the developer carrier to the image carrier.

When the first operation (S2) is performed with the developer carrier positioned at the second position, the predetermined distance L can be set as follows.

For example, in the first operation, in the image forming apparatus of the present invention, the length (d2) of the surface of the image carrier in the rotation direction A of the image carrier from the development position Y3 to the transfer position Y2 at a predetermined distance L. Can be.

By setting the predetermined distance (L) to the length d2, the jam toner on the image carrier can be efficiently moved to the intermediate transfer body.

Further, in the image forming apparatus of the present invention, the intermediate transfer body 31 is configured to be movable to a third position Z3 capable of contacting the image carrier 1 and a fourth position Z4 capable of being separated from the image carrier 1. You may. After the second operation (S3), the control unit positions the intermediate transfer body at the fourth position and rotates the image carrier and the intermediate transfer body for a predetermined time t (or a predetermined distance L) in the third operation (or a predetermined distance L). A2, A3) can be performed.

This makes it possible to prevent reverse transfer of the toner to the image carrier of the downstream station.

Further, in the image forming apparatus of the present invention, the intermediate transfer body 31 is configured so that an electric potential can be applied, and the control unit is the same as when forming an image in the third operation (A2, A3). Control may be performed so that the potential of the polarity is applied to the intermediate transfer body.

This makes it possible to promote the transfer of toner from the image carrier to the intermediate transfer body.

Further, the image forming apparatus of the present invention may have a recovery developer box 11B for accommodating the developer recovered from the intermediate transfer member 31 by the cleaning member 11A.

Further, in the image forming apparatus of the present invention, a cartridge (process cartridge) 7 including an image carrier 1, a second cleaning member (cleaning member) 6 for cleaning the surface 1y of the image carrier, and a frame 13A is provided. Can have. Further, the cartridge can be attached to and detached from the apparatus main body 100A of the image forming apparatus. The frame of the cartridge supports the image carrier 1 and the second cleaning member 6, and also houses the developer recovered from the surface of the image carrier by the second cleaning member (recovery toner box). ) 14 can be configured to form.

Further, in the image forming apparatus of the present invention, the cartridge 7 can include a second frame body (frame body) 4a. Further, the volume of the recovery developer chamber (recovery toner box) 14 can be set to be smaller than that of the developer storage chamber (toner storage chamber) 18b. The second frame 4a of the cartridge can be configured to form a developer accommodating chamber 18b for accommodating a developer for developing an electrostatic latent image on an image carrier.

Further, the image forming apparatus 100 of the present invention includes an image carrier (photoreceptor drum 1), a developer carrier (development roller 17), an exposure member (exposure apparatus 30), and an intermediate transfer body (intermediate transfer belt 31). ), And a cleaning member 11A for cleaning the surface 31a of the intermediate transfer body. The developer carrier can carry the developer supplied to the image carrier for developing the electrostatic latent image and can come into contact with the image carrier. Further, the exposure member irradiates and exposes the surface of the image carrier.

Further, the image forming apparatus has a secondary transfer member (secondary transfer roller 33) that secondarily transfers the developer image from the intermediate transfer body to the recording medium (recording material 35) for recording the developer image T1. .. Then, the image forming apparatus 100 has a fixing member (fixing device 34) for fixing the developer image transferred to the recording medium by the secondary transfer member. Further, the image forming member 100 also includes a detecting member D for detecting the conveyed state of the recording medium and a control unit (system controller 901).

The image carrier supports the developer image T1 developed from the electrostatic latent image T0 on the surface 1y and is rotatable. Further, the intermediate transfer body 31 is in contact with the surface 1y of the image carrier, carries the developer image T1 transferred from the image carrier, and is rotatable.

When the detection member D detects that the transport state of the recording medium is defective, the control unit causes the first operation (S2) and the second operation (S3) to be performed in order, and stays on the surface of the image carrier. The developed developer (jam toner H) is transferred from the image carrier to the intermediate transfer body. In the first operation (S2), the rotation operation of the image carrier and the intermediate transfer body is temporarily stopped, and then the rotation operation of the image carrier and the intermediate transfer body is restarted. Further, in the second operation (S3), after the rotation operation of the image carrier and the intermediate transfer body is restarted, when the surface of the image carrier moves a predetermined distance by the rotation operation of the image carrier, the image carrier Stop the rotation operation of.

Then, in the first operation, the fixing operation of the fixing member is stopped.

The predetermined distance is equal to or greater than the length of the surface of the image carrier in the rotation direction of the image carrier from the development position (Y3) in contact with the developer carrier to the transfer position (Y2) in contact with the intermediate transfer body.
Moreover, it is equal to or less than the distance moved by the surface of the image carrier within the period in which the recording medium moves from the secondary transfer position (Y5) in the secondary transfer member to the fixing position (Y4) in the fixing member.

As a result, when jam occurs, the jam toner remaining on the surface of the image carrier can be efficiently transferred to the intermediate transfer body, and as a result, the volume for the recovered toner in the process cartridge can be reduced. .. That is, it is possible to handle jam processing while minimizing the capacity of the process cartridge. In particular, it is possible to reduce the amount of paper wrapped around the fixing member during jamming.

1 (a to d) Photoreceptor drum (image carrier)
1y Surface of photoconductor drum (image carrier) 11A Cleaning member 17 Developing roller (developer carrier)
30 Exposure device (exposure member)
31 Intermediate transfer belt (intermediate transfer body)
31a Surface of intermediate transfer belt (intermediate transfer body) 33 Secondary transfer roller (secondary transfer member)
34 Fixing device (fixing member)
35 Recording material (recording medium)
100 Image forming device 901 System controller (control unit)
D Detection member H (jam) Toner (developer)
S2 step (first operation)
S3 step (second operation)
T0 Electrostatic latent image T1 Developer image Y2 Transfer position Y3 Development position Y4 Fixation position Y5 Secondary transfer position

Claims (11)

A rotatable image carrier that supports a developer image developed from an electrostatic latent image on the surface,
A developer carrier that carries a developer supplied to the image carrier for developing the electrostatic latent image and can come into contact with the image carrier.
An exposure member that irradiates and exposes the surface of the image carrier,
An intermediate transfer body that is in contact with the surface of the image carrier, carries the developer image transferred from the image carrier, and can rotate.
A cleaning member that cleans the surface of the intermediate transfer member,
A secondary transfer member that secondarily transfers the developer image from the intermediate transfer body to a recording medium for recording the developer image.
A fixing member for fixing the developer image transferred to the recording medium by the secondary transfer member, and a fixing member.
A detection member that detects the transport state of the recording medium, and
Control unit and
An image forming apparatus equipped with
The control unit
When the detection member detects that the transport state of the recording medium is poor, the first operation of continuing the rotational operation of the image carrier and the intermediate transfer body without stopping the image carrier and the intermediate transfer body.
After the defect is detected, when the surface of the image carrier moves a predetermined distance by the rotation operation of the image carrier, the second operation of stopping the rotation operation of the image carrier is performed in order. ,
In the first operation,
The fixing operation of the fixing member is stopped,
The predetermined distance is
It is equal to or longer than the length of the surface of the image carrier in the rotation direction of the image carrier from the developing position in contact with the developer carrier to the transfer position in contact with the intermediate transfer body.
Moreover, the distance from the secondary transfer position on the secondary transfer member to the fixing position on the fixing member within the period in which the recording medium moves is less than or equal to the distance the surface of the image carrier has moved. Image forming apparatus. The predetermined distance is
It is characterized in that it is equal to or longer than the length of the surface of the image carrier in the rotation direction of the image carrier from the exposure position on the surface of the image carrier by the exposure member to the transfer position in contact with the intermediate transfer body. The image forming apparatus according to claim 1. The predetermined distance is
The image forming apparatus according to claim 2, wherein the length is the length of the surface of the image carrier in the rotation direction of the image carrier from the exposure position to the transfer position. The developer carrier is
It is configured to be movable between a first position capable of contacting the image carrier and a second position capable of being separated from the image carrier.
The image forming according to any one of claims 1 to 3, wherein the control unit moves the developer carrier from the first position to the second position in the first operation. apparatus. In the first operation,
The image forming apparatus according to claim 4, wherein the predetermined distance is the length of the surface of the image carrier in the rotation direction of the image carrier from the development position to the transfer position. .. The intermediate transcript is
It is configured to be movable to a third position where it can come into contact with the image carrier and a fourth position where it can be separated from the image carrier.
After the second operation, the control unit positions the intermediate transfer body at the fourth position and causes the image carrier and the intermediate transfer body to perform a third operation of rotating the intermediate transfer body in a predetermined time. The image forming apparatus according to any one of claims 1 to 5. The intermediate transcript is configured so that an electric potential can be applied.
The image according to claim 6, wherein the control unit controls in the third operation so that a potential having the same polarity as that at the time of image formation for forming an image is applied to the intermediate transfer body. Forming device. The image forming apparatus according to any one of claims 1 to 7, further comprising a recovered developer box for accommodating the developer recovered from the intermediate transfer member by the cleaning member. With the image carrier
A second cleaning member that cleans the surface of the image carrier,
A cartridge including a frame body that supports the image carrier and the second cleaning member and forms a recovery developer chamber for accommodating the developer recovered from the surface of the image carrier by the second cleaning member. Have,
The image forming apparatus according to any one of claims 1 to 8, wherein the cartridge is removable from the apparatus main body of the image forming apparatus. The cartridge includes a second frame that forms a developer accommodating chamber for accommodating a developer for developing an electrostatic latent image on the image carrier.
The image forming apparatus according to claim 9, wherein the recovery developer chamber has a smaller volume than the developer accommodating chamber. A rotatable image carrier that supports a developer image developed from an electrostatic latent image on the surface,
A developer carrier that carries a developer supplied to the image carrier for developing the electrostatic latent image and can come into contact with the image carrier.
An exposure member that irradiates and exposes the surface of the image carrier,
An intermediate transfer body that is in contact with the surface of the image carrier, carries the developer image transferred from the image carrier, and can rotate.
A cleaning member that cleans the surface of the intermediate transfer member,
A secondary transfer member that secondarily transfers the developer image from the intermediate transfer body to a recording medium for recording the developer image.
A fixing member for fixing the developer image transferred to the recording medium by the secondary transfer member, and a fixing member.
A detection member that detects the transport state of the recording medium, and
Control unit and
An image forming apparatus equipped with
The control unit
When the detection member detects that the transport state of the recording medium is poor, the rotation operation of the image carrier and the intermediate transfer body is temporarily stopped, and then the rotation of the image carrier and the intermediate transfer body is performed. The first operation to resume the operation and
After resuming the rotation operation of the image carrier and the intermediate transfer body, the rotation operation of the image carrier is stopped when the surface of the image carrier moves a predetermined distance by the rotation operation of the image carrier. The second operation to be performed and the second operation to be performed in order,
In the first operation,
The fixing operation of the fixing member is stopped,
The predetermined distance is
It is equal to or longer than the length of the surface of the image carrier in the rotation direction of the image carrier from the developing position in contact with the developer carrier to the transfer position in contact with the intermediate transfer body.
Moreover, the distance from the secondary transfer position on the secondary transfer member to the fixing position on the fixing member within the period in which the recording medium moves is less than or equal to the distance the surface of the image carrier has moved. Image forming apparatus.

Images