JP6921540B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus using an electrophotographic method.

In an image forming apparatus using an electrophotographic image forming process, a process cartridge method is widely adopted in which the electrophotographic photosensitive member and the process means acting on the electrophotographic photosensitive member are integrated and can be attached to and detached from the image forming apparatus. Has been done. A new process cartridge is sealed by a sealing member, and an invention has been proposed in which the sealing member of the process cartridge is automatically opened when the new process cartridge is attached to the image forming apparatus (for example,). See Patent Document 1). Further, the drive source of the means for opening the seal member of the process cartridge may also serve as the drive of the developing unit and the photoconductor. In this case, opening the seal member has a problem that a larger load is applied to the drive source than when the image is formed. For example, as a method for reducing the load applied to the drive source, an invention for reducing the load applied to the drive source is disclosed by providing a drive row capable of outputting high torque in addition to the normally used drive row (for example,). See Patent Document 2). Further, regarding the driving of the developing unit, an invention that enables the developing roller and the photosensitive drum to be sequentially brought into contact with each other and separated from each other is disclosed (see, for example, Patent Document 3).

Japanese Unexamined Patent Publication No. 2005-0997766 JP-A-2009-069177 Japanese Unexamined Patent Publication No. 2006-292868

However, in a configuration in which the developing roller and the photosensitive drum are sequentially brought into contact with each other and separated from each other, when the driving source of the developing roller and the driving source of the means for opening the sealing member are the same, the following problems occur. In a configuration in which the developing rollers of a plurality of process cartridges are driven by one motor, not only the developing rollers of a specific process cartridge but also the developing rollers of other process cartridges are connected to the drive source. Therefore, when the seal member of a specific process cartridge is opened, a plurality of other developing rollers are also driven at the same time, and the load applied to the motor becomes large. As a result, it becomes necessary to increase the torque that can be output from the motor, which may lead to an increase in cost and size. From the above, it is necessary to reduce the load applied to the drive source when the seal member is opened.

The present invention has been made under such circumstances, and an object of the present invention is to reduce the load applied to the drive source when the seal member is opened.

In order to solve the above-mentioned problems, the present invention includes the following configurations.

(1) The photoconductor, the developing roller that applies toner to the photoconductor, the accommodating portion that accommodates the toner applied to the photoconductor by the developing roller, and the developing roller is not supplied with toner from the accommodating portion. A first having a sealing member for sealing the toner supply port from the accommodating portion to the developing roller, and a winding means for winding and opening the sealing member to open the supply port. An image forming apparatus including a plurality of one cartridges in which the plurality of first cartridges are arranged in parallel in the order in which image formation is performed, the first motor for driving the plurality of developing rollers, and the photoconductor. A switching means for switching between a state in which the developing roller is separated from the developing roller and a state in which the developing roller is in contact with the developing roller, a second motor for driving the switching means, and a control means for controlling the first motor and the second motor. The first motor drives a plurality of the winding means corresponding to the plurality of developing rollers, and the second motor is said to be rotated in the first rotation direction. When the developing roller and the photoconductor are brought into contact with each other or separated from each other in the order in which the image is formed by the switching means and rotated in the second rotation direction opposite to the first rotation direction, the above. The developing roller of the cartridge in which the image is finally formed among the plurality of first cartridges is brought into contact with the photoconductor by the switching means, and the control means drives the winding means by the first motor. When the sealing member is opened, the second motor is controlled so that all of the plurality of developing rollers are not driven by the first motor, and the plurality of sealing members are controlled. When all of the above are unopened, the second motor is rotated in the second rotation direction to open the sealing member of the cartridge in which the image formation is finally performed, and then the second motor. The image forming apparatus is characterized in that the sealing member of the remaining first cartridge is opened from upstream to downstream by rotating the first cartridge in the first rotation direction.
(2) The photoconductor, the developing roller that applies toner to the photoconductor, the accommodating portion that accommodates the toner applied to the photoconductor by the developing roller, and the developing roller are not supplied with toner from the accommodating portion. A first having a sealing member for sealing the toner supply port from the accommodating portion to the developing roller, and a winding means for winding and opening the sealing member to open the supply port. An image forming apparatus including a plurality of one cartridges in which the plurality of first cartridges are arranged in parallel in the order in which image formation is performed, the first motor for driving the plurality of developing rollers, and the photoconductor. A switching means for switching between a state in which the developing roller is separated from the developing roller and a state in which the developing roller is in contact with the developing roller, a second motor for driving the switching means, and a control means for controlling the first motor and the second motor. The first motor drives a plurality of the winding means corresponding to the plurality of developing rollers, and the second motor is said to be rotated in the first rotation direction. When the developing roller and the photoconductor are brought into contact with each other or separated from each other in the order in which the image is formed by the switching means and rotated in the second rotation direction opposite to the first rotation direction, the above. The developing roller of the cartridge in which the image is finally formed among the plurality of first cartridges is brought into contact with the photoconductor by the switching means, and the control means drives the winding means by the first motor. When the sealing member is opened, the second motor is controlled so that all of the plurality of developing rollers are not driven by the first motor, and the plurality of sealing members are controlled. Of the cartridges, when the sealing member of the cartridge arranged at the most downstream is unopened, the cartridge in which the image is finally formed by rotating the second motor in the first rotation direction. An image forming apparatus characterized by opening a sealing member.

According to the present invention, it is possible to reduce the load applied to the drive source when the seal member is opened.

Cross-sectional view of the image forming apparatus of Examples 1 and 2. Block diagram of the image forming apparatus of Examples 1 and 2. The figure explaining the contact and separation between the photosensitive drum of Examples 1 and 2 and a developing roller. The figure which shows the state of contact and separation between a photosensitive drum of Examples 1 and 2 and a developing roller. A diagram showing the configuration of the toner container 23Y of Examples 1 and 2, and a diagram showing the winding of the toner seal. Timing chart showing opening control of the toner seal of Example 1 Flow chart showing the opening process of the toner seal of Example 1. Timing chart showing opening control of the toner seal of Example 2 Flow chart showing the opening process of the toner seal of the second embodiment

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential for the means for solving the present invention.

<Structure of image forming apparatus>
As shown in FIG. 1, the 4-drum full-color image forming apparatus 1 (hereinafter referred to as an image forming apparatus 1) includes a plurality of process cartridges with respect to the main body 2 of the image forming apparatus 1 (hereinafter referred to as an apparatus main body 2). ing. Specifically, it is equipped with four-color process cartridges PY, PM, PC, and PK. Here, Y represents yellow, M represents magenta, C represents cyan, and K represents black at the end of the code, which are omitted below unless necessary. The four-color process cartridges PY, PM, PC, and PK can be attached to and detached from the apparatus main body 2, that is, they can be attached and detached. Each of the process cartridges P constitutes an image forming station (also referred to as an image forming unit) of each color component in a state of being mounted on the apparatus main body 2. The image forming station has at least a developing device 63 and a photosensitive drum 61, which will be described later. Further, the apparatus main body 2 has an intermediate transfer belt unit 5 having an intermediate transfer belt 51 which is an intermediate transfer body (rotating body), and a fixing device 7 for heating and fixing toner. The image forming stations are arranged in series along the moving direction A (clockwise direction in FIG. 1) of the intermediate transfer belt 51.

Further, each process cartridge P has a photosensitive drum 61 which is an image carrier, and the photosensitive drum 61 is sequentially arranged in parallel along the moving direction of the intermediate transfer belt 51 which is a transfer target. Each process cartridge P is arranged in the order of, for example, yellow, magenta, cyan, and black from the upstream side to the downstream side in the moving direction of the intermediate transfer belt 51. In other words, the cartridges PY, PM, PC, and PK are arranged in parallel from upstream to downstream in the order in which image formation is performed. The order of arranging the process cartridges P is not limited to this order. An electrostatic latent image is formed on the surface of the photosensitive drum 61 by a laser exposure device 21 which is an exposure means, toner is applied by a developer 63 which is a developing means, and the electrostatic latent image is developed by the toner. Further, each process cartridge P integrally has a charger 62 as a charging means, a developing device 63, and a drum cleaner 65 as a cleaning means around the photosensitive drum 61.

In each process cartridge P, the charger 62 is arranged on the outer peripheral surface of the photosensitive drum 61 to uniformly charge the surface of the photosensitive drum 61. The laser exposure device 21 irradiates the photosensitive drum 61 with a laser beam (indicated by a alternate long and short dash line in FIG. 1) according to the image data to form an electrostatic latent image on the surface of the photosensitive drum 61. The developer 63 develops an electrostatic latent image formed on the photosensitive drum 61 (on the photoconductor) using toners of colors (yellow, magenta, cyan, black) corresponding to each photosensitive drum 61. Members, devices, and the like that contribute to forming the toner image on the photosensitive drum 61 function as forming means. The developing roller 64, which is a developer carrier provided in the developing device 63, can be separated from the photosensitive drum 61 together with the developing device 63 to stop the rotation. By separating the developing roller 64 from the photosensitive drum 61, deterioration of the developing agent can be prevented. That is, the developing roller 64 is configured so as to be able to come into contact with the photosensitive drum 61 or to be separated from the photosensitive drum 61 together with the developing device 63 (hereinafter, referred to as abutting / separating possible). In the following description, the state in which the developing roller 64 is in contact with the photosensitive drum 61 may be referred to as simply contacting, and the state in which the developing roller 64 is separated from the photosensitive drum 61 may be referred to as simply separating. Further, the position where the developing roller 64 abuts on the photosensitive drum 61 is referred to as an abutting position. The drum cleaner 65 removes the toner adhering to the surface of the photosensitive drum 61 after the toner image on the photosensitive drum 61 is sequentially transferred to the intermediate transfer belt 51 by the primary transfer roller 52 which is a transfer means. The primary transfer roller 52 is provided so as to face the position where the intermediate transfer belt 51 is sandwiched together with the photosensitive drum 61, and forms a primary transfer portion together with the photosensitive drum 61.

The intermediate transfer belt unit 5 includes an intermediate transfer belt 51, and three rollers, a drive roller 53 for tensioning the intermediate transfer belt 51, a tension roller 54, and a secondary transfer opposed roller 55. The intermediate transfer belt 51 is conveyed in the moving direction A by rotationally driving the drive roller 53 by a motor (not shown) that drives the intermediate transfer belt 51. The tension roller 54 is configured to be movable in the horizontal direction shown in FIG. 1 according to the length of the intermediate transfer belt 51.

A belt cleaner 58 for collecting toner on the intermediate transfer belt 51 is installed in the vicinity of the tension roller 54. The longitudinal direction is the axial direction of the roller, and is the width direction orthogonal to the moving direction A of the intermediate transfer belt 51. Further, at a position where the intermediate transfer belt 51 of the secondary transfer opposed roller 55 is sandwiched, the secondary transfer roller 81 forming the secondary transfer portion together with the secondary transfer opposed roller 55 is arranged so as to face each other. The secondary transfer roller 81 is held by the transfer transfer unit 8.

At the lower part of the apparatus main body 2, a feeding unit 3 for feeding the recording material Q to the secondary transfer unit is arranged. The feeding unit 3 includes a cassette 31 containing a plurality of recording materials Q, a feeding roller 32, a retard roller pair 33 for preventing double feeding, a transport roller pair 34, 35, and a registration roller pair (hereinafter referred to as a resist roller pair). ) 36 etc. are provided. Discharge rollers 37, 38, and 39 are provided in the transport path on the downstream side in the transport direction of the fuser 7.

The image forming apparatus 1 includes an image forming control unit (simply referred to as a control unit) 12, and the control unit 12 receives output signals of each sensor, and also performs driving timing of the driving unit, latent image formation, and the like. It controls the image formation operation such as the timing of.

<Structure of control unit>
FIG. 2 is a block diagram showing a control unit 12 and the like of the image forming apparatus 1. The control unit 12 has a CPU 121, which is a processor that executes a program to execute data processing and input / output processing, a ROM 122 that stores data, a program, and the like, and a RAM 123. The control unit 12 controls, for example, a timer mapped to the memory space or the IO space and each control unit. Functions controlled by the control unit 12 include, for example, an exposure control unit 13, a high-voltage control unit 14, a drive control unit 15, a sensor control unit 16, and the like. The control timer 17 is used for measuring time and the like. The exposure control unit 13 drives the laser exposure device 21, drives a scanner motor (not shown), corrects the amount of laser light, and the like. The high-voltage control unit 14 charges the photosensitive drum 61 required for image formation, the developing voltage, the primary transfer voltage to the intermediate transfer belt 51, the secondary transfer voltage to the recording material Q, and the cleaning voltage for the belt cleaner 58. Etc. are applied. The drive control unit 15 drives the image-forming motor (not shown) of the photosensitive drum 61, the developing roller 64, and the intermediate transfer belt 51, and the motor (not shown) that conveys the recording material Q.

The above configuration will be described in more detail. The high-voltage control unit 14 controls the voltage applied to the charger 62 and the voltage of the charger for charging the developing roller 64. The high-voltage control unit 14 controls a charger that applies a positive voltage to the primary transfer roller 52 when forming an image and a negative voltage when collecting toner. It may be considered that the high voltage control unit 14 itself includes a charger.

The stepping motor control unit 187 controls the stepping motor 91, which is a second motor. The motor drive circuit 28 controls the DC brushless motor 30YMC, which is the first motor described later, and the DC brushless motor 30K, which is the third motor.

<Operation of image forming device>
The image forming operation of the image forming apparatus 1 will be described. When the image forming operation is started, the recording material Q in the cassette 31 is fed by the feeding roller 32, then separated one by one by the retard roller pair 33, and passes through the transport rollers pairs 34, 35, and the like. It is conveyed to the resist roller pair 36. On the other hand, in parallel with the transport operation of the recording material Q, for example, in the yellow process cartridge PY, the surface of the photosensitive drum 61Y is uniformly negatively charged by the charger 62, and the laser beam is irradiated by the laser exposure device 21Y. The exposure is performed. As a result, an electrostatic latent image corresponding to the yellow image component of the image signal is formed on the surface of the photosensitive drum 61Y.

The developing roller 64Y in the developing device 63Y is gradually moved while being rotationally driven, and comes into contact with the photosensitive drum 61Y from a state of being separated from the photosensitive drum 61Y. As a result, the electrostatic latent image of the photosensitive drum 61Y is developed by the developing device 63Y using the yellow toner charged negatively, visualized as a yellow toner image, and appears as a visual image. The yellow toner image formed on the photosensitive drum 61Y is transferred from the photosensitive drum 61Y onto the intermediate transfer belt 51 by the primary transfer roller 52 to which the primary transfer voltage is supplied (hereinafter referred to as primary transfer). ).

Such a series of image forming operations is also sequentially performed in other process cartridges PM, PC, and PK with a time difference according to the interval and the transport speed. The developing roller 64 is sequentially brought into contact with the photosensitive drum 61 while rotating in order to prevent deterioration of the developing agent. That is, the developing roller 64 starts rotating on the way from the state of being separated from the photosensitive drum 61 to the state of being in contact with the photosensitive drum 61. Then, the toner images of each color formed on each photosensitive drum 61 are sequentially superimposed on the corresponding regions on the intermediate transfer belt 51 at the primary transfer unit of each color and primary transfer is performed. The region on which the toner image of each color is transferred on the intermediate transfer belt 51 is referred to as an image forming region on the intermediate transfer belt 51. When the developing operation is completed, the developing roller 64 prevents deterioration of the developing agent even when the process cartridge P arranged on the downstream side in the moving direction A of the intermediate transfer belt 51 is undergoing primary transfer. , Sequentially separated from the photosensitive drum 61 and the rotation is stopped. The toner image composed of four colors superimposed and transferred on the intermediate transfer belt 51 is moved to the secondary transfer unit as the intermediate transfer belt 51 rotates.

On the other hand, the recording material Q whose skew is corrected by the resist roller pair 36 is sent out to the secondary transfer unit in timing with the toner image on the intermediate transfer belt 51. The four-color toner images on the intermediate transfer belt 51 are collectively transferred onto the recording material Q by the secondary transfer roller 81 that abuts on the intermediate transfer belt 51 with the recording material Q in between (hereinafter, secondary). Transcription). The recording material Q to which the toner image is transferred in the secondary transfer unit is conveyed to the fixing device 7, heated and pressurized, so that the unfixed toner image is fixed on the recording material Q. The recording material Q for which the fixing process has been completed is discharged to the upper surface of the apparatus main body 2 by the discharge rollers 37, 38, and 39 and loaded. In the above steps, a full-color toner image composed of a plurality of colors is formed on the recording material Q.

<Attachment and separation switching operation between the photosensitive drum and the developing roller>
A mechanism (switching means) for switching between contact and separation between the developing roller 64 and the photosensitive drum 61 will be described with reference to FIG. The stepping motor 91, which is a drive source for switching the contact and separation of the developing roller 64, has a worm gear 97 fixed to the output shaft of the stepping motor 91, and a shaft in which a pinion gear meshing with the worm gear 97 is coaxially fixed. Rotate 92. A worm gear 93 for driving a cam gear 94 of each color is fixed to the shaft 92, and when the shaft 92 rotates, the phase of the cam 95 fixed coaxially with the cam gear 94 changes. The cam 95 is a plate cam having a peripheral edge formed so that the radius from the center of rotation differs depending on the phase. The peripheral edge of the cam 95 presses or releases the side surface of the process cartridge P according to the phase of the cam 95.

The side surface of the process cartridge P serving as the cam follower is the side surface 69a of the housing 69 of the developing device 63 on which the developing roller 64 is pivotally supported. The housing 69 of the developing device 63 is pivotally supported by a shaft 99 parallel to the photosensitive drum 61 and the like with respect to the housing 70 in which the photosensitive drum 61 is pivotally supported near the center thereof. The housing 70 on which the photosensitive drum 61 is pivotally supported is fixed to the apparatus main body 2, and the housing 69 of the developing device 63 is camped between the housing 70 and the housing 69 of the developing device 63. An elastic member 98 such as a spring for urging the 95 is provided. As a result, the developing roller 64 swings around the shaft 99 in response to the movement of the housing 69 of the developing device 63 driven by the cam 95. As a result, the developing roller 64 comes into contact with or separates from the photosensitive drum 61 according to the phase of the cam 95. Since the minimum distance between the developing roller 64 and the photosensitive drum 61 is 0 (at the time of contact), the amount of swing of the housing 69 of the developing device 63 is regulated not only by the radius of the cam 95 but also by the photosensitive drum 61. become. In this way, the contact and separation between the photosensitive drum 61 and the developing roller 64 can be switched. Further, in conjunction with the mechanism for switching the contact and separation between the developing roller 64 and the photosensitive drum 61, the developing roller 64 is in a state where the drive is transmitted or cut off from the drive source that rotationally drives the developing roller 64. ..

The contact state and separation state between the developing roller 64 and the photosensitive drum 61 in the first embodiment are the standby state (or the total separation state) shown in FIG. 3 (A) and the full-color contact state shown in FIG. 3 (B). And the monocolor contact state shown in FIG. 3C. In the standby state, all cams 95 (95Y, 95M, 95C, 95K) are in contact with the side surface 69a of the process cartridge P (PY, PM, PC, PK) at the maximum radius. Therefore, the elastic member 98 is pressed from the housing 69 side of the developing device 63 toward the housing 70 side of the photosensitive drum 61. As a result, the developing device 63 swings clockwise in FIG. 3A about the axis 99, and all the developing rollers 64 (64Y, 64M, 64C, 64K) are exposed to the photosensitive drum 61 (61Y, 61M). , 61C, 61K). The maximum radius of the cam 95 is a radius necessary for separating the developing roller 64 from the photosensitive drum 61.

In the full-color contact state shown in FIG. 3 (B), all cams 95 (95Y, 95M, 95C, 95K) are in contact with the side surface 69a of the process cartridge P (PY, PM, PC, PK) with a substantially minimum radius. It is separated. Therefore, the housing 69 of the developing device 63 is urged toward the cam 95 by the elastic member 98, and the developing device 63 swings in the counterclockwise direction in FIG. 3B about the axis 99. The minimum radius of the cam 95 is a radius necessary for bringing the developing roller 64 and the photosensitive drum 61 into contact with each other. As a result, all the developing rollers 64 (64Y, 64M, 64C, 64K) are in contact with the photosensitive drum 61 (61Y, 61M, 61C, 61K).

In the monocolor contact state shown in FIG. 3 (C), the cams 95 (95Y, 95M, 95C) of the three colors of yellow (Y), magenta (M), and cyan (C) shown in FIG. 3 (C) are It abuts on the side surface 69a of the three-color process cartridge P (PY, PM, PC) with the maximum radius. The black (K) cam 95K is in contact with the side surface 69aK of the process cartridge PK at a distance or approximately the minimum radius, and only the black developing roller 64K is in contact with the photosensitive drum 61K. Hereinafter, the distance from the center of the cam 95 to the position where the cam 95 is in contact with the side surface 69a of the process cartridge P is also referred to as a cam radius.

Next, the relationship between the phase change of the cam 95 and the three selectable states is shown in the cam diagram of FIG. In FIG. 4, the development separation is the side where the developing roller 64 and the photosensitive drum 61 are separated from each other, and the cam radius is large. On the other hand, the development contact is the side where the development roller 64 and the photosensitive drum 61 come into contact with each other, and the cam radius is small. FIG. 4 shows only the profile of the cam 95, and does not show the actual contact and separation between the developing roller 64 and the photosensitive drum 61.

FIG. 4 (i) shows a cam diagram of development contact and development distance at the black image forming station, and FIG. 4 (ii) shows a cam diagram of development contact and development separation at the cyan image forming station. FIG. 4 (iii) shows a cam diagram of development contact and development distance at the magenta image forming station, and FIG. 4 (iv) shows a cam diagram of development contact and development separation at the yellow image forming station. Further, a predetermined position (or timing) at which the development roller 64 starts rotation is indicated by a broken line between the development separation and the development contact (development roller rotation). In FIG. 4, when the stepping motor 91 rotates in the forward rotation direction, which is the first rotation direction, the state changes from left to right (forward rotation direction). When the stepping motor 91 rotates in the forward direction, the development contact is started from yellow located on the upstream side in the moving direction of the intermediate transfer belt 51, and the development contact is performed in the order of magenta, cyan, and black toward the downstream side. .. Further, when the stepping motor 91 rotates in the reverse rotation direction, which is the second rotation direction opposite to the first rotation direction, the state changes from right to left (reverse rotation direction). When the stepping motor 91 rotates in the reverse direction, the development contact is started from black located on the downstream side in the moving direction of the intermediate transfer belt 51, and the development contact is performed in the order of cyan, magenta, and yellow toward the upstream side. .. Further, (A) corresponds to the fully separated state (standby state) of FIG. 3 (A), (B) corresponds to the full-color contact state of FIG. 3 (B), and (C) corresponds to FIG. 3 (C). Corresponds to the monocolor contact state of.

For example, in the case of the black image forming station shown in FIG. 4 (i), when the stepping motor 91 rotates in the forward direction, the development roller 64K starts moving from the development separation state to the contact state at a predetermined timing in the standby state. The cam 95K rotates so as to be processed. The rotation of the developing roller 64 is started at a predetermined timing while the developing roller 64K is moving toward the photosensitive drum 61K. When the cam 95K is further rotated, the development contact state is reached at a predetermined timing. When the rotation of the cam 95K is maintained, the development contact moves toward the development separation at a predetermined timing. On the way, the rotation of the developing roller 64K is stopped. Hereinafter, the phase state of the cam 95 corresponding to the series of contact and separation operations of the developing roller 64 is referred to as a profile. As shown in FIG. 4, by giving each cam 95 a profile and shifting the phase of all cams 95, it is possible to switch between the three states shown in FIG. The switching of states is also referred to as mode switching. Further, in the following description, the contact between the photosensitive drum 61 and the developing roller 64 is simply referred to as contact or development contact, and the separation between the photosensitive drum 61 and the developing roller 64 is simply referred to as separation or development separation.

When performing a normal printing operation, the developing roller 64 can switch from a standby state to a full-color contact state or from a standby state to a monocolor contact state according to the timing at which image formation is started. First, switching between the development contact state and the development separation state when performing full-color printing will be described. The state in which the developing roller 64 and the photosensitive drum 61 are in contact with each other is referred to as a development contact state (or contact state), and the state in which the developing roller 64 and the photosensitive drum 61 are in contact with each other is referred to as a development separation state (separation state). Further, when the development contact state and the development separation state are described without distinction, it is also referred to as a development contact separation state. The stepping motor 91 is stopped in the standby state. The standby state can be determined, for example, by providing a specific cam with a sensor indicating the rotation phase of the cam. Further, it can be determined by once determining the position of the standby state, using that position as a reference, measuring the number of steps for one round of the cam, and measuring the number of steps when the motor is driven.

(Full color print)
When performing full-color printing, the stepping motor 91 is driven in the forward rotation direction by a predetermined number of steps in accordance with the timing at which image formation is started. When the driving of the stepping motor 91 in the forward rotation direction is started, the developing roller 64 and the photosensitive drum 61 of each image forming station come into contact with each other via an indefinite state, and become a full-color contact state. The indefinite state is a state in which the developing roller 64 and the photosensitive drum 61 cannot be said to be in contact with each other or separated from each other in terms of control due to variations in the members. As shown in FIG. 4, the order of contact is yellow ⇒ magenta ⇒ cyan ⇒ black. Image formation is started from the image forming station where the contact of the developing roller 64 with the photosensitive drum 61 is completed. The number of steps of the stepping motor 91 at this time is set so that the steps are stopped in the full-color contact state in which the contact between the developing roller 64 and the photosensitive drum 61 is completed at all the image forming stations. When the image formation is completed, the stepping motor 91 is driven again in the forward rotation direction by a predetermined number of steps. When the driving of the stepping motor 91 in the forward rotation direction is started, the developing roller 64 and the photosensitive drum 61 are separated from each other via an indefinite state and return to the standby state. As shown in FIG. 4, the order of separation is yellow ⇒ magenta ⇒ cyan ⇒ black. In this way, image formation is completed. The number of steps of the stepping motor 91 at this time is set so that the cam 95 stops in the standby state. That is, it starts from the standby state, stops in the full-color contact state, and then returns to the standby state again.

(Monocolor print)
Next, the switching control between the development contact state and the development separation state when monocolor printing is performed will be described. When performing monocolor printing, the stepping motor 91 is driven in a predetermined number of steps in the reverse rotation direction in accordance with the timing at which image formation is started. When the driving of the stepping motor 91 in the reverse rotation direction is started, the developing roller 64 and the photosensitive drum 61 come into contact with each other only in black via an indefinite state. That is, the black developing roller 64K and the photosensitive drum 61K come into contact with each other, and image formation is started at the black image forming station. The number of steps of the stepping motor 91 is such that the steps are stopped when the contact between the black developing roller 64K and the photosensitive drum 61K is completed. When the monocolor image formation is completed, the stepping motor 91 is driven in the forward rotation direction by a predetermined number of steps. When the driving of the stepping motor 91 in the forward rotation direction is started, the black developing roller 64K and the photosensitive drum 61K are separated from each other to finish printing. The number of steps of the stepping motor 91 is such that the steps are stopped when the separation of all the image forming stations is completed.

If the load applied to the stepping motor 91 becomes large, there is a risk of step-out. Therefore, as shown in FIG. 3C, the stepping motor 91 is further driven in the reverse rotation direction from the state where only the black developing roller 64K and the photosensitive drum 61K are in contact with each other to be exposed to the cyan developing roller 64C. The drum 61C cannot be brought into contact with the drum 61C.

In the image forming step, the image forming apparatus 1 switches the development contact state and the development separation state between the developing roller 64 and the photosensitive drum 61 from the separation state to the contact state, or vice versa. At that time, the drive start timing (start timing) and the number of steps of the stepping motor 91 in the standby state and the drive start timing and the number of steps of the stepping motor 91 in the full-color contact state are predetermined.

<Explanation of the mechanism for opening the seal of the toner container>
Next, an opening operation (seal pulling operation) for opening the seal, which is a sealing member of the process cartridge, will be described. The configuration and drive configuration of the toner container 66Y in the process cartridge PY of FIG. 5A will be described. The toner container 66, which is a storage unit, stores the toner applied to the photosensitive drum 61 by the developing roller 64. The toner 72Y in the toner container 66Y is stirred by the stirring sheet 76Y attached to the stirring shaft 75Y. Further, the stirring shaft 75Y is rotationally driven by a DC brushless motor 30 (hereinafter, simply referred to as a motor 30). Then, the toner 72Y that is flipped up by the rotational operation of the stirring sheet 76Y reaches the developing roller 64Y. When the process cartridge PY is not used, a toner seal 74Y is provided between the toner container 66Y and the developing roller 64Y so that the toner 72Y cannot enter the developing roller 64Y side. The toner seal 74, which is a sealing member, seals the toner supply port from the toner container 66 to the developing roller 64 so that the toner is not supplied from the toner container 66 to the developing roller 64 until it is opened.

In FIG. 5A, the motor 30 includes a rotor 29 and a motor drive circuit 28. The CPU 121, which is a control means, outputs a control signal for controlling the rotation speed of the rotor 29 to the motor 30 to drive the motor 30. After that, the CPU 121 monitors the cycle of the detection signal for detecting the rotation speed of the rotor 29 output from the motor 30, and controls so that the rotation speed of the motor 30 is kept constant. The motor 30YMC is connected to the photosensitive drum 61Y. Further, the motor 30YMC is connected to the developing roller 64Y, the stirring shaft 75Y, and the take-up portion 73Y of the toner seal 74Y via a clutch 71Y that connects and disconnects the drive to the toner container 66Y. The winding unit 73, which is a winding means, winds and opens the toner seal 74 to open the above-mentioned supply port. The stepping motor 91 (FIG. 3), which is a drive source, drives the contact separation operation of the developing roller 64Y with the photosensitive drum 61Y and the engagement / disengagement operation of the clutch 71Y.

FIG. 4 shows the relationship between the engagement and disengagement of the clutch 71 of the developing roller 64 and the phase of the cam 95 in each process cartridge P. The broken line of rotation of the developing roller 64 shown in FIG. 4 represents the relationship between the engagement and disengagement of the clutch 71 of the developing roller 64 of each process cartridge P and the phase of the cam 95. When the phase of the cam 95 is on the development separation side from the broken line of the development roller rotation, the clutch 71 of the development roller 64 is released, and when it is on the development contact side, the clutch 71 of the development roller 64 is engaged. Is shown. That is, when the cam diagram intersects the broken line of the developing roller rotation, the clutch 71 is engaged or disengaged. The clutch 71Y is engaged at the timing of rotation of the developing roller of FIG. 4 while the developing roller 64 is being moved from the separated state to the contacted state by the stepping motor 91. Further, the clutch 71Y is disengaged at the timing of rotation of the developing roller of FIG. 4 while the developing roller 64 is being moved from the contact state to the separated state by the stepping motor 91.

FIG. 5B shows a winding configuration of the toner seal 74Y of the process cartridge PY. The gears 77Y and 78Y are connected to the motor 30 via the clutch 71Y. The driving force transmitted from the motor 30 via the gears 77Y and 78Y changes the rotation direction by 90 ° by the worm gear 79Y. After the rotation direction is changed by 90 ° by the worm gear 79Y, the driving force is transmitted to the gear 82Y, and the take-up shaft 83 that winds up the toner seal 74Y rotates. As a result, the toner seal 74Y is wound around the take-up shaft 83, so that the toner container 66Y sealed by the toner seal 74Y is opened.

Further, when the toner seal 74 of the toner container 66 is opened, it is necessary to perform the following operations in order to prevent the cleaning blade 84, which is a collecting means, from being turned over. That is, it is necessary to supply toner to the cleaning blade 84 of the process cartridge P that has opened the toner seal 74 of the toner container 66 to reduce the friction between the photosensitive drum 61 and the cleaning blade 84.

<Explanation of seal opening order in Example 1>
The drive source of each developing roller 64 of the first embodiment will be described. In the first embodiment, the developing roller 64Y, the developing roller 64M, and the developing roller 64C are driven by the motor 30YMC (see FIG. 2) which is the same drive source. Further, the developing roller 64K is driven by a motor 30K (see FIG. 2). The process cartridges PY, PM, and PC correspond to the first cartridge, and the process cartridge PK corresponds to the second cartridge. Further, the process cartridge PC is a cartridge arranged at the most downstream side among the first cartridges, and is a cartridge in which image formation is performed at the end. Further, the process cartridge PK is a cartridge arranged further downstream than the cartridge arranged most downstream in the first cartridge.

Conventionally, when opening the toner seal, the development contact separation state is switched in order from the process cartridge P arranged on the upstream side in the moving direction of the intermediate transfer belt 51, and the toner seal 74 is transmitted at a position where the drive of the developing roller 64 is transmitted. Was opened one by one. However, if the toner seal 74 is opened in such an order, the following problems occur. For example, when the toner seal 74C of the process cartridge PC is opened, the drive is transmitted to the developing roller 64Y and the developing roller 64M by the motor 30YMC which is the same drive source, and a large load is applied to the motor 30YMC. There is a fear. The present invention proposes a control in which the drive torque of the motor 30YMC when opening the toner seal 74 is minimized in this configuration.

The timing t1, which is the driving state of the yellow developing roller 64Y shown in FIG. 4, is a state in which the yellow clutch 71Y is engaged and the driving force of the motor 30YMC is transmitted to the developing roller 64Y via the clutch 71Y. The timing t2, which is the driving state of the yellow and magenta developing rollers 64Y and 64M shown in FIG. 4, is a state in which the yellow and magenta developing rollers 64Y and 64M clutches 71Y and 71M are connected. The timing t2 is a state in which the driving force of the motor 30YMC is transmitted to the developing rollers 64Y and 64M, respectively, via the clutches 71Y and 71M.

The timing t4, which is the driving state of the black and cyan developing rollers 64C and 64K shown in FIG. 4, is a state in which the cyan and black developing rollers 64C and 64K clutches 71C and 71K are connected. The timing t4 is a state in which the driving forces of the motors 30YCM and 30K are transmitted to the developing rollers 64C and 64K via the clutches 71C and 71K, respectively.

<Timing chart when opening the toner seal>
FIG. 6 is a timing chart showing the control of the opening operation of the toner seal 74 in the first embodiment by the state of the cam 95 and the state of the stepping motor 91. 6 (i) to 6 (iv) are graphs similar to those of FIGS. 4 (i) to 4 (iv). FIG. 6V shows the development contact separation state (switching, CK drive, full color, etc.) of the developing roller 64, and can be said to show the state of the cam 95. For example, "switching" indicates a state in which the cam 95 is rotated by the stepping motor 91 and the development contact separation state is switched. Further, for example, in "CK drive", the cyan and black cams 95C and 95K rotate from the phase in the development separated state, the clutches 71C and 71K are connected, and the driving force is transmitted from the motors 30YMC and 30K to the developing rollers 64C and 64K. It shows the state of being driven (rotated). “Full color” indicates a state in which the phase of the cam 95 is as shown in FIG. 3 (B). FIG. 6 (vi) shows the state of the stepping motor 91 (reverse rotation, stop, forward rotation, etc.). FIG. 6 (vii) shows the control performed by the CPU 121, and “toner seal opening” indicates the period during which the opening operation of the toner seal 74 in the unopened process cartridge P is controlled. Further, "toner supply to the blade" indicates a period during which the operation of supplying toner to the cleaning blade 84 is controlled in the process cartridge P in which the toner seal 74 is opened.

The opening order of the toner seal 74 in the first embodiment will be described with reference to FIG. Here, a case where the toner seals 74Y, 74M, and 74C of the cartridges PY, PM, and PC, which are the first cartridges, are all unopened will be described. In Example 1, it is assumed that the toner seal 74K of the cartridge PK is also unopened. When the CPU 121 determines that the toner seals 74 of all the process cartridges P are unopened, the CPU 121 starts driving the motor 30. The CPU 121 determines that the toner seal 74 of the process cartridge P has not been opened by a known method. For example, the process cartridge P may have a storage means such as a non-volatile memory, and the storage means may store information on whether or not the process cartridge P is new. The CPU 121 reads information from the storage means included in the process cartridge P, and determines whether or not the toner seal 74 is unopened based on the read information. Next, the CPU 121 reversely rotates the stepping motor 91 and stops it at a position where the driving forces of the motors 30YMC and 30K are transmitted to the developing roller 64C and the developing roller 64K. At this time, as shown in FIG. 6 (i), the developing roller 64K is rotating and is in contact with the photosensitive drum 61K. As shown in FIG. 6 (ii), the developing roller 64C is rotating, but is not in contact with the photosensitive drum 61C. Further, as shown in FIGS. 6 (iii) and 6 (iv), the developing rollers 64Y and 64M driven by the motor 30YMC are disengaged from each other in the clutch 71Y and 71M in the development separated state, and the motor 30YMC is disconnected. Not rotated by. First, the CPU 121 is located on the downstream side in the moving direction of the intermediate transfer belt 51, and starts the opening operation of the toner seals 74C and 74K from the two process cartridge PCs and PKs driven by different motors (motor 30YMC, motor 30K). do.

After waiting for a time until the opening of the toner seals 74C and 74K of the process cartridge PC and the process cartridge PK is completed, the stepping motor 91 is rotated in the forward direction. As a result, the developing rollers 64C and 64K are put into a development separated state. The forward rotation of the stepping motor 91 is maintained, and the stepping motor 91 is stopped at a position where the driving force of the motor 30YMC is transmitted to the developing roller 64Y. At this time, as shown in FIG. 6 (iv), the developing roller 64Y is rotating, but is not in contact with the photosensitive drum 61Y. Further, the developing rollers 64M and 64C driven by the motor 30YMC, which is the same drive source, are not rotating because the clutches 71M and 71C are disconnected from each other. After opening the toner seals 74C and 74K, the CPU 121 is located on the upstream side in the moving direction of the intermediate transfer belt 51, and opens the toner seal 74Y of the process cartridge PY driven by the motor 30YMC and the motor 30K.

After waiting for a time until the opening of the toner seal 74Y of the process cartridge PY is completed, the stepping motor 91 is further rotated forward and stopped at a position where the driving force of the motor 30YMC is transmitted to the developing roller 64M. At this time, as shown in FIG. 6 (iv), the developing roller 64Y is in contact with the photosensitive drum 61Y by further rotating the stepping motor 91 in the forward direction. Further, as shown in FIG. 6 (iii), the developing roller 64M is rotating, but is not in contact with the photosensitive drum 61M. Further, in the developing roller 64C driven by the motor 30YMC which is the same driving source, the clutch 71C is disengaged and the developing roller 64C is not rotating. After opening the toner seal 74Y, the CPU 121 is located downstream of the process cartridge PY in the moving direction of the intermediate transfer belt 51, and opens the toner seal 74M of the process cartridge PM driven by the motor 30YMC.

After waiting for a time until the opening of the toner seal 74M of the process cartridge PM is completed, the stepping motor 91 is further rotated forward. As a result, the full-color state is set, and the developing rollers 64Y, 64M, 64C, and 64K are in contact with the photosensitive drums 61Y, 61M, 61C, and 61K. When the full color state is reached, the stepping motor 91 is stopped to supply toner to the cleaning blades 84 of all the process cartridges P.

<Toner seal opening control process>
Next, the opening control process of the toner seal 74 when all the toner seals 74 of the toner container 66 of the process cartridge P of the first embodiment are unopened will be described with reference to the flowchart of FIG. The flowchart of FIG. 7 is executed when the door that is opened and closed when the process cartridge P is replaced changes from the closed state to the open state and then changes to the closed state. Further, the flowchart of FIG. 7 is executed when all the toner seals 74 of the toner container 66 of the process cartridge P are unopened when the power of the image forming apparatus 1 is turned on. This process is stored in the ROM 122 as a control sequence program.

In step 181 (hereinafter referred to as S), the CPU 121 drives a motor 30 (30YMC, 30K) which is a drive source for opening the toner seal 74. In S182, the CPU 121 reversely rotates the stepping motor 91 by a predetermined number of steps in order to start the contact operation between the developing roller 64 and the photosensitive drum 61. As a result, as shown in FIG. 4, the black and cyan developing rollers 64K and 64C stop at positions where the driving forces of the motors 30K and 30YMC are transmitted to the developing rollers 64K and 64C (separated state → CK developing roller). Drive). In S183, the CPU 121 resets and starts the timer of the CPU 121. In S184, the CPU 121 waits for a predetermined time until the opening of the black and cyan toner seals 74K and 74C is completed. That is, in S184, the CPU 121 refers to the timer to determine whether or not the predetermined time has elapsed, and if it is determined that the predetermined time has not elapsed, the process is returned to S184 and the predetermined time has elapsed. If it is determined, the process proceeds to S185. By this process, the cyan and black toner seals 74C and 74K are opened. The predetermined time required to open the toner seal 74 is measured in advance by an experiment or the like and stored in, for example, the ROM 122, and the same applies to the other process cartridge P.

In S185, the CPU 121 rotates the stepping motor 91 in the forward direction by a predetermined number of steps. As a result, as shown in FIG. 4, the yellow developing roller 64Y stops at a position where the driving force of the motor 30YMC is transmitted to the developing roller 64Y (CK developing roller drive → Y developing roller drive). The CPU 121 also stops the timer. In S186, the CPU 121 resets the timer and starts it. In S187, the CPU 121 waits for a predetermined time until the opening of the yellow toner seal 74Y is completed. That is, in S187, the CPU 121 refers to the timer to determine whether or not the predetermined time has elapsed, and if it determines that the predetermined time has not elapsed, the process is returned to S187 and the predetermined time has elapsed. If it is determined, the process proceeds to S188. By this process, the yellow toner seal 74Y is opened.

In S188, the CPU 121 rotates the stepping motor 91 in the forward direction by a predetermined number of steps. As a result, as shown in FIG. 4, the yellow and magenta developing rollers 64Y and 64M stop at a position where the driving force of the motor 30YMC is transmitted to the developing rollers 64Y and 64M (Y developing roller drive → YM developing roller drive). ). The CPU 121 also stops the timer. In S189, the CPU 121 resets the timer and starts it. In S190, the CPU 121 waits for a predetermined time until the magenta toner seal 74M is completely opened. That is, in S190, the CPU 121 refers to the timer to determine whether or not a predetermined time has elapsed, and if it determines that the predetermined time has not elapsed, the process is returned to S190 and the predetermined time has elapsed. If it is determined, the process proceeds to S191. This process opens the magenta toner seal 74M. This completes the opening operation of the toner seal 74 in all the process cartridges P.

In S191, the CPU 121 rotates the stepping motor 91 in the forward direction by a predetermined number of steps. As a result, as shown in FIG. 4, the contact state between the developing roller 64 and the photosensitive drum 61 is brought into a full-color state (YM developing roller drive → full-color state). In S192, the CPU 121 performs a printing operation using the exposure control unit 13 and the high voltage control unit 14, and supplies toner to the cleaning blades 84 of all the image forming stations. In S193, the CPU 121 rotates the stepping motor 91 in the forward direction by a predetermined number of steps, puts the developing roller 64 and the photosensitive drum 61 in the standby state shown in FIG. 4, and ends the process (full color state → standby state).

As described above, in the first embodiment, the number of developing rollers 64 driven by one motor and the number of process cartridges P for opening the toner seal 74 are set to a predetermined number or less. The CPU 121 controls the take-up portions 73Y, 73M, 73C by the motor 30YMC to open the toner seals 74Y, 74M, 74C as follows. That is, the CPU 121 controls the stepping motor 91 so that all of the plurality of developing rollers 64Y, 64M, and 64C are not driven by the motor 30YMC. As a result, the torque applied to the motors 30YMC for driving the plurality of developing rollers 64Y, 64M, 64C can be set to be equal to or less than a predetermined torque according to the capacity of the motors 30YMC. As a result, the torque of the motor 30 that drives the developing roller 64 can be suppressed to a small value. As a result, it is possible to suppress an increase in the cost of the motor 30 and an increase in the size of the motor 30. As described above, according to the first embodiment, it is possible to reduce the load applied to the drive source when the seal member is opened.

In the first embodiment, when the toner seals 74 of the toner containers 66 in all the image forming stations are unopened, the method of opening the toner seals 74 in the order not exceeding the torque that can be output by the motor 30 has been described. In the second embodiment, for example, a case where the toner seals 74Y and 74M of the yellow and magenta toner containers 66Y and 66M have been opened and the toner seal 74C of the cyan toner container 66C has not been opened will be described. That is, when the cyan toner seal 74C located on the most downstream side in the moving direction of the intermediate transfer belt 51 among the developing rollers 64Y, 64M, 64C driven by the motor 30YMC, which is the same drive source, is unopened. Is. In such a case, in the second embodiment, a method of shortening the time until the toner supply to the cleaning blade 84C described in the first embodiment is completed will be described. The toner seal 74K of the black toner container 66K may be opened or unopened. The drive source of each developing roller 64 is the same as the configuration described in the first embodiment, and the description thereof will be omitted.

When opening only the toner seal 74C of the cyan toner container 66C, the black and cyan developing rollers 64K and 64C shown in the timing t4 of FIG. 4 described in the first embodiment are stopped at the driven state. Then, the cyan developing roller 64C is not in contact with the photosensitive drum 61C. Therefore, the toner cannot be supplied to the cleaning blade 84 immediately after the toner seal 74C is opened. Further, as described in the first embodiment, the cyan developing roller 64C and the photosensitive drum 61C are further rotated in the reverse direction from the driving state of the black and cyan developing rollers 64K and 64C shown in FIG. It cannot be brought into contact.

From the above, when opening only the toner seal 74C of the cyan toner container 66C, when opening the toner seal 74C by stopping the developing roller 64C at the position in the driving state shown in FIG. 4, the following It is necessary to perform the operation like. That is, after the opening of the toner seal 74C is completed, the stepping motor 91 must be rotated forward to pass through the standby state, and after the standby state is changed to the full color state, the toner needs to be supplied to the cyan cleaning blade 84C. .. Therefore, in the second embodiment, when only the toner seal 74C of the cyan toner container 66C is opened, the magenta and cyan developing rollers 64M and 64C are stopped in the driving state, and the toner seal 74C is opened.

The driving states of the magenta and cyan developing rollers 64M and 64C shown at the timing t3 in FIG. 4 are states in which the driving force of the motor 30YMC is transmitted to the developing rollers 64M via the clutch 71M. Further, the timing t3 is a state in which the cyan developing roller 64C and the photosensitive drum 61C are in contact with each other. The toner seal 74C of the cyan toner container 66C is opened at the position of the developing rollers 64M and 64C at the timing t3 shown in FIG. As a result, after the opening operation of the toner seal 74C is completed, the toner can be supplied to the cleaning blade 84C without performing the contact operation of the developing roller 64C.

<Timing chart when opening the toner seal>
FIG. 8 is a timing chart showing the control of opening the toner seal 74C of the second embodiment in the state of the cam 95 and the state of the stepping motor 91. 8 (i) to 8 (vii) are graphs similar to those of FIGS. 6 (i) to 6 (vii). The opening operation of the toner seal 74C in the second embodiment will be described with reference to FIG. When the CPU 121 determines that only the process cartridge PC is unopened, the CPU 121 rotates the stepping motor 91 in the forward direction. As a result, the developing rollers 64M and 64C stop at the position where the driving force of the motor 30YMC is transmitted. Toner is supplied to the cleaning blade 84C of the process cartridge PC after waiting for a time until the opening of the toner seal 74C of the process cartridge PC is completed. When the toner supply is completed, the CPU 121 rotates the stepping motor 91 in the forward direction, shifts to the standby state, and then stops.

<Toner seal opening control process>
Next, the opening control process in the process cartridge PY, PM, and PC in the second embodiment when only the toner seal 74 of the cyan toner container 66C is unopened will be described with reference to the flowchart of FIG. The flowchart of FIG. 9 is executed when the door that opens and closes when the process cartridge P is replaced changes from the closed state to the open state and then changes to the closed state. Further, the flowchart of FIG. 9 shows a case where only the toner seal 74C of the toner container 66C of the process cartridge PC is unopened among the process cartridges PY, PM, and PC when the power of the image forming apparatus 1 is turned on. Is executed. This process is stored in the ROM 122 as a control sequence program.

In S281, the CPU 121 rotates the stepping motor 91 in the forward direction by a predetermined number of steps. As a result, as shown in FIG. 4, the magenta and cyan developing rollers 64M and 64C are brought into a driving state (separated state → MC developing roller drive). In S282, the CPU 121 drives the motor 30YMC, which is a drive source for opening the toner seal 74C. In S283, the CPU 121 resets the timer and starts it. Wait for a predetermined time until the opening of the cyan toner seal 74C is completed in S284. That is, the CPU 121 refers to the timer to determine whether or not a predetermined time has elapsed, and if it determines that the predetermined time has not elapsed, returns the process to S284 and determines that the predetermined time has elapsed. If so, the process proceeds to S285. By this process, the cyan toner seal 74C is opened.

In S285, the CPU 121 performs a printing operation using the exposure control unit 13 and the high pressure control unit 14, and supplies toner to the cyan cleaning blade 84C. Since the cyan developing roller 64C is already in contact with the photosensitive drum 61C during the opening operation of the toner seal 74C, the toner is immediately applied to the cleaning blade 84C after the opening operation of the toner seal 74 is completed. Can be supplied. In S286, the CPU 121 rotates the stepping motor 91 in the forward direction by a predetermined number of steps, puts it in the standby state shown in FIG. 4 (MC development roller drive → separated state), and ends the process.

As described above, in the second embodiment, the number of developing rollers 64 driven by one drive source and the number of process cartridges P for opening the toner seal 74 are set to a predetermined number or less. Further, in the process cartridge P for opening the toner seal 74 of the toner container 66, the toner seal 74 is opened at a position where the developing roller 64 and the photosensitive drum 61 are in contact with each other. This makes it possible to reduce the load on the motor 30 and shorten the time required to complete the toner supply to the cleaning blade 84. As described above, according to the second embodiment, it is possible to reduce the load applied to the drive source when the seal member is opened.

P Process Cartridge 30 DC Brushless Motor 61 Photosensitive Drum 64 Developing Roller 73 Winding Part 74 Toner Seal 91 Stepping Motor 121 CPU

Claims (10)

The photoconductor, a developing roller for applying toner to the photoconductor, an accommodating portion for accommodating the toner applied to the photoconductor by the developing roller, and the accommodating portion so as not to supply toner to the developing roller. A first cartridge having a sealing member for sealing a toner supply port from an accommodating portion to the developing roller, and a winding means for winding and opening the sealing member to open the supply port. An image forming apparatus comprising a plurality of the first cartridges arranged in parallel in the order in which the image forming is performed.
A first motor for driving the plurality of developing rollers,
A switching means for switching between a state in which the photoconductor and the developing roller are separated from each other and a state in which the developing roller is in contact with each other.
A second motor for driving the switching means and
A control means for controlling the first motor and the second motor,
With
The first motor drives a plurality of the winding means corresponding to the plurality of developing rollers.
When the second motor is rotated in the first rotation direction, the developing roller and the photoconductor are brought into contact with each other or separated from each other in the order in which image formation is performed by the switching means, and the first When the image is rotated in the second rotation direction opposite to the rotation direction of the above, the developing roller and the photoconductor of the cartridge in which the image is finally formed among the plurality of the first cartridges by the switching means are pressed. Make a contact,
In the control means, when the winding means is driven by the first motor to open the sealing member, all of the plurality of developing rollers are not driven by the first motor. To control the second motor so as to
When the plurality of sealing members are all unopened, the second motor is rotated in the second rotation direction to open the sealing member of the cartridge in which the image formation is finally performed, and then the sealing member is opened. An image forming apparatus, characterized in that the second motor is rotated in the first rotation direction to open the sealing member of the remaining first cartridge from upstream to downstream. It said control means, after the last image formed by the switching means is brought into contact with the developing roller of the cartridge and a photosensitive member is performed, thereby separating the developing roller and the photosensitive member cartridge most located downstream when doing so, the image forming apparatus according to claim 1, characterized in that rotating the second motor to the first rotational direction. The driving force of the first motor is transmitted to the developing roller at a predetermined position between the state where the developing roller and the photoconductor are separated from each other and the state where the photoconductor is in contact with the developing roller. The image forming apparatus according to claim 1 or 2. A forming means for forming a toner image on the photoconductor and
A recovery means for recovering the toner on the photoconductor and
With
After opening all of the plurality of sealing members, the control means further rotates the second motor in the first rotation direction to bring the plurality of developing rollers into contact with the plurality of the photoconductors. The method according to any one of claims 1 to 3 , wherein the toner is supplied to the collecting means by forming a toner image on the plurality of photoconductors by the forming means in the state. Image forming device. The photoconductor, a developing roller for applying toner to the photoconductor, an accommodating portion for accommodating the toner applied to the photoconductor by the developing roller, and the accommodating portion so as not to supply toner to the developing roller. A first cartridge having a sealing member for sealing a toner supply port from an accommodating portion to the developing roller, and a winding means for winding and opening the sealing member to open the supply port. An image forming apparatus comprising a plurality of the first cartridges arranged in parallel in the order in which the image forming is performed.
A first motor for driving the plurality of developing rollers,
A switching means for switching between a state in which the photoconductor and the developing roller are separated from each other and a state in which the developing roller is in contact with each other.
A second motor for driving the switching means and
A control means for controlling the first motor and the second motor,
With
The first motor drives a plurality of the winding means corresponding to the plurality of developing rollers.
When the second motor is rotated in the first rotation direction, the developing roller and the photoconductor are brought into contact with each other or separated from each other in the order in which image formation is performed by the switching means, and the first When the image is rotated in the second rotation direction opposite to the rotation direction of the above, the developing roller and the photoconductor of the cartridge in which the image is finally formed among the plurality of the first cartridges by the switching means are pressed. Make a contact,
In the control means, when the winding means is driven by the first motor to open the sealing member, all of the plurality of developing rollers are not driven by the first motor. To control the second motor so as to
Among the sealing member of multiple, the last by the sealing member of the cartridge which is arranged most downstream is the case of the unopened rotating the second motor to the first rotational direction images forming device you characterized by unsealing the sealing member of the cartridge in which the image formation is performed on. When the control means rotates the second motor in the first rotation direction to open the sealing member of the cartridge arranged at the most downstream side, the control means of the cartridge in which the image formation is finally performed. The image forming apparatus according to claim 5 , wherein the second motor is rotated until the developing roller and the photoconductor are in contact with each other. A forming means for forming a toner image on the photoconductor and
A recovery means for recovering the toner on the photoconductor and
With
The control means is on the photoconductor of the cartridge in which the last image formation is performed by the forming means without further rotating the second motor after opening the sealing member of the cartridge arranged at the most downstream. The image forming apparatus according to claim 6 , wherein the toner is supplied to the collecting means of the cartridge in which the image is finally formed by forming the toner image on the surface. A third motor different from the first motor,
A second cartridge, which is arranged in parallel with the cartridge in which the image is finally formed and in which the developing roller and the winding means are driven by the third motor,
With
When the second motor is rotated in the second rotation direction, the timing is earlier than the contact between the developing roller and the photoconductor in the cartridge in which the image formation is finally performed in the first cartridge. the image forming apparatus according to any one of claims 1 to 7, characterized in that the developing roller in the second cartridge and the photosensitive member are abutting. The image forming apparatus according to claim 8 , wherein the first motor and the third motor are DC brushless motors. The image forming apparatus according to any one of claims 1 to 9 , wherein the second motor is a stepping motor.

Images