JP5084469B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to a process cartridge that is detachably attached to an electrophotographic image forming apparatus such as a copying machine or a printer, and more particularly, to open a seal member provided to seal an opening of a new process cartridge. It is about.

2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic image forming process, a process cartridge method in which a photosensitive member and a process unit acting on the photosensitive member are integrated and detachable from the main body of the image forming device is widely adopted. Has been.
In such a process cartridge, a toner storage container which is a developer storage container constituting a part of the developing device has an opening for supplying the toner stored in the toner storage container to the developing container side. The opening is sealed with a toner seal as a seal member when the process cartridge is not used.

When the process cartridge is used for the first time, the process cartridge is attached to the image forming apparatus. Then, a process cartridge having an automatic toner seal opening device that automatically opens a toner seal that seals the opening of the toner container and an image forming apparatus that can drive the automatic toner seal take-up device of the process cartridge are known. It has been. (Patent Documents 1 and 2)
Japanese Patent Laid-Open No. 1-193872, JP-A-62-127876

  For the automatic winding of the process cartridge seal, many methods are used that utilize the driving force of the process cartridge developing device (including the developing unit and the toner storage container) and the motor driving the photosensitive drum.

In this case, the torque specification required for the motor is increased by the load torque during the seal winding operation, compared with the case where only the developing device and the photosensitive drum are driven.
Further, with respect to the torque of the developing device of the process cartridge, it is generally known that the toner in the toner storage container becomes clogged when vibration is applied to the process cartridge during transportation. As a result, when the toner in the toner container is agitated for the first time in a new process cartridge, the torque during agitation increases due to the influence of the clogged toner.

In other words, the torque specification required for the motor is the sum of all of the drive torque of the developing device, the drive torque of the photosensitive drum, and the seal take-up torque, assuming that the toner is clogged. It will increase. FIG. 16 shows an example of the transition of the load torque applied to the motor at the time of winding the toner seal, and the torque when stirring the stuck toner is described as tapping torque.
The above-described toner clogging and toner seal winding during transportation are torques required only when a new process cartridge is used for the first time. In view of this, Japanese Patent Application Laid-Open No. 2005-221976 describes a case where a stepping motor is used and the motor driving speed is reduced during toner seal winding to compensate for the motor output torque.
However, the method described in Japanese Patent Application Laid-Open No. 2005-221976 has a problem that the time required for winding the toner seal becomes long, which causes discomfort to the user.

  The toner seal automatic winding device is generally mounted on a product having a relatively high specification such as a high-speed monochrome image forming apparatus or a color image forming apparatus. Further, in many of these image forming apparatuses, a brushless motor is used instead of the stepping motor described in JP-A-2005-221976.

  The present invention has been made under such circumstances. Even when the rotational speed of the rotational drive source slightly changes due to the torque at the time of opening the sealing member of the toner container, the rotational drive is not detected. An object of the present invention is to provide an image forming apparatus capable of reducing the torque specification of the source and obtaining cost merit.

  In order to solve the above-described problems, in the present invention, an image forming apparatus is configured as described in (1) below.

(1) In the image forming apparatus Luke cartridges is detachable having a toner container opening with a sealing member is sealed,
In a state in which the cartridge is mounted, a rotary drive source for driving the front hear cartridges,
And opening means for opening said sealing member with the driving force of said rotary driving source,
A new-product detection means the front is attached to the image forming apparatus asked cartridges detects whether new,
And abnormality detecting means you detect the rotation drive source of the rotating Utatekoto always when the rotational speed of the rotary driving source exceeds a first speed Dohan enclosed predetermined,
When the toner container by the new-product detection means detects that the new, by setting the first speed Dohan circumference to a second speed range for unsealing the toner container, the rotary drive source start to begin the opening sealing operation Ru good to said opening means, after the unsealing operation of the toner container is judged complete, and control means for switching from said second fast Dohan circumference in the first speed range ,
An image forming apparatus comprising:

  According to the present invention, even when the rotational speed of the rotational drive source changes slightly due to the torque at the time of opening the sealing member of the toner container, speed abnormality is not detected, the torque specification of the rotational drive source is reduced, and the cost merit is reduced. An image forming apparatus that can be obtained can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples.

  FIG. 1 is a cross-sectional view illustrating a schematic configuration of a “color image forming apparatus” according to the first embodiment. A color image forming apparatus (hereinafter referred to as a main body) shown in FIG. 1 includes process cartridges 5Y, 5M, 5C, and 5K that are detachable from the main body. These four process cartridges 5Y, 5M, 5C, and 5K have the same structure, but images of toners of different colors, that is, yellow (Y), magenta (M), cyan (C), and black (Bk) are displayed. It differs in the point to form. The process cartridges 5Y, 5M, 5C, and 5K include toner containers 23Y, 23M, 23C, and 23K, photosensitive drums 1Y, 1M, 1C, and 1K as image carriers, charging rollers 2Y, 2M, 2C, and 2K, and a developing roller 3Y, respectively. , 3M, 3C, 3K. Further, it has drum cleaning blades 4Y, 4M, 4C, 4K and waste toner containers 24Y, 24M, 24C, 24K.

  Laser units 7Y, 7M, 7C, and 7K are disposed below the process cartridges 5Y, 5M, 5C, and 5K, and exposure based on image signals is performed on the photosensitive drums 1Y, 1M, 1C, and 1K.

  The photosensitive drums 1Y, 1M, 1C, and 1K are charged to predetermined negative potentials by the charging rollers 2Y, 2M, 2C, and 2K, and then electrostatic latent images are formed by the laser units 7Y, 7M, 7C, and 7K, respectively. Is done. This electrostatic latent image is reversely developed by the developing rollers 3Y, 3M, 3C, and 3K, and negative toner is attached to form toner images of Y, M, C, and Bk, respectively.

The intermediate transfer belt unit includes an intermediate transfer belt 8, a driving roller 9, and a secondary transfer counter roller 10. Further, primary transfer rollers 6Y, 6M, 6C, and 6K are disposed inside the intermediate transfer belt 8 so as to face the photosensitive drums 1Y, 1M, 1C, and 1K, and transfer bias is applied by a bias applying unit (not shown). Is applied.
Each photosensitive drum rotates in the direction of the arrow, the intermediate transfer belt 8 rotates in the direction of arrow A, and a positive bias is applied to the primary transfer rollers 6Y, 6M, 6C, and 6K. As a result, the toner images formed on the photosensitive drums 1Y, 1M, 1C, and 1K are primarily transferred onto the intermediate transfer belt 8 sequentially from the toner images on the photosensitive drum 1Y, and the four color toner images are overlapped. Is conveyed to the secondary transfer roller 11.

The feeding / conveying device 12 includes a paper feed roller 14 that feeds the transfer material P from the paper feed cassette 13 that houses the transfer material P, and a transport roller pair 15 that transports the fed transfer material P. Yes. Then, the transfer material P conveyed from the feeding / conveying device 12 is conveyed to the secondary transfer roller 11 by the registration roller pair 16.
In the transfer from the intermediate transfer belt 8 to the transfer material P, a positive bias is applied to the secondary transfer roller 11 so that the four color toner images on the intermediate transfer belt 8 are transferred to the transferred transfer material P. Secondary transfer.

  After transfer of the toner image, the transfer material P is conveyed to the fixing device 17 and heated and pressed by the fixing film 18 and the pressure roller 19 to fix the toner image on the surface. The fixed transfer material P is discharged to the outside by the discharge roller pair 20.

  On the other hand, the toner remaining on the surface of the photosensitive drums 1Y, 1M, 1C, and 1K after the toner image transfer is removed by the drum cleaning blades 4Y, 4M, 4C, and 4K. Further, the toner remaining on the intermediate transfer belt 8 after the secondary transfer to the transfer material P is removed by the transfer belt cleaning blade 21, and the removed toner is collected in a waste toner collecting container 22.

  1 is a control board on which an electric circuit for controlling the main body is mounted. The CPU 40 is mounted on the control board 80. The CPU 40 collectively controls the operation of the main body, such as control of a drive source (not shown) related to conveyance of the transfer material P, a process cartridge drive source (not shown), control related to image formation, and control related to failure detection. It is what you are doing.

Next, the configuration of the toner container 23 in the process cartridge 5 will be described.
In FIG. 2, the toner 27 in the toner container 23 is stirred by a stirring sheet 26 attached to the stirring shaft 25. The stirring shaft 25 is driven to rotate by a drive source (not shown). Then, the toner 27 splashed up by the rotation operation of the stirring sheet 26 reaches the developing roller 3.
When the process cartridge 5 is new (corresponding to a new one in the claims), a toner seal 28 is provided between the toner container 23 and the developing roller 3 so that the toner 27 does not enter the developing roller 3 side. It has a configuration.

  FIG. 3 shows a configuration in which the toner seal 28 is wound up when the process cartridge 5 is used. The gears 30 and 31 are connected to a driving source (not shown) that drives the photosensitive drum 1, the developing roller 3, and the stirring shaft 25. The driving force transmitted by the gears 30 and 31 is rotated 90 ° by the worm gear 32 and then transmitted to the gear 33 to rotate the winding shaft 34 that winds the toner seal 28. As a result, the toner container 23 sealed by the toner seal 28 is opened by causing the toner seal 28 to be wound around the take-up shaft 34 (corresponding to the opening operation in the claims).

Next, a method of driving a DC brushless motor that is a driving source of the photosensitive drum 1, the developing roller 3, and the stirring shaft 25 will be described.
FIG. 4 shows a drive circuit configuration of a DC brushless motor (hereinafter referred to as motor 39), which includes Y-connected coils 55 to 57 and a rotor 58. Furthermore, Hall elements 59 to 61 are provided as position detecting means for the rotor 58, and these Hall elements 59 to 61 are elements in which a voltage appears at both ends of the semiconductor piece by detecting a magnetic field, and the position of the rotor can be detected. Become. The output is amplified by the amplifier 62 and input to the motor drive control circuit 42.
Reference numeral 41 denotes a drive circuit unit of the motor 39, which includes a motor drive control circuit 42, high-side FETs 43 to 45, and low-side FETs 46 to 48. The FETs 43 to 48 are connected to U, V, and W which are end portions of Y-connected coils, respectively, and are phase-excited sequentially by ON / OFF control according to the phase switching signal output from the motor drive control circuit 42. To switch the rotor. The phase switching signal is generated by the motor drive control circuit 42 by detecting the drive signal from the output port of the CPU 40 and the position signal of the rotor 58 generated from the Hall elements 59-61. The rotation of the motor 39 related to phase switching is based on the principle that each phase is sequentially excited by switching the potentials of the end portions U, V, W in the order shown in FIG.

  FIG. 6 is a control block diagram relating to the rotational speed control of the motor 39. Here, the speed command (acceleration or deceleration) sent from the CPU 40 to the motor 39 is amplified by the error amplifying unit 65 and sent to the PWM driving unit 66. In the PWM drive unit 66, the FETs 43 to 48 in the motor drive control circuit 42 are PWM-driven, and the rotor 58 rotates. The rotation speed detection unit 68 in FIG. 6 will be described with reference to FIGS.

  In FIG. 7, reference numeral 70 denotes a rectangular wave-shaped FG pattern formed on a printed circuit board (not shown) of the motor 39. A magnet 71 composed of a plurality of poles attached to the inner surface of the rotor 58 rotates on the FG pattern 70, and a state as shown in FIG. At this time, the induced voltage generated in the FG pattern 70 shown in FIG. 8 is a sine wave shown in FIG. 9 (the waveform is round 1, a round numeral cannot be used, so it is round 1), and the rotation speed detection in FIG. Sent to section 68. Here, the rotation speed detection unit 68 is configured by a comparator (not shown) having hysteresis characteristics, and an induced voltage (waveform round 1) generated in the FG pattern 70 is converted into a pulse signal (waveform round 2) (hereinafter referred to as “waveform round 2”). , Referred to as an FG signal) and sent to the CPU 40. The CPU 40 monitors the cycle of the FG signal (waveform round 2) sent from the rotation speed detection unit 68, and issues a speed command (acceleration or deceleration) so that the cycle of the FG signal (waveform round 2) becomes a desired cycle. By sending it to the motor 39, feedback control of the rotational speed of the motor 39 becomes possible. The FG signal corresponds to a pulse signal synchronized with the rotation operation in the claims.

  Next, a method for calculating the speed command in the CPU 40 will be described with reference to FIG.

  The CPU 40 has an internal clock with a predetermined cycle, and uses this to monitor the cycle of the FG signal (waveform 2). In this embodiment, it is assumed that the period between the falling edges of the FG signal is monitored, and the CPU 40 corresponds to the number of rotations of the motor 39 corresponding to 10 pulses of the internal clock of the CPU 40 between the falling edges of the FG signal. It is assumed that such speed control is performed.

  In FIG. 10, when the actual rotational speed is slower than the target rotational speed, that is, when the number of internal clocks counted between FG pulses is 11 pulses or more (11 pulses in FIG. 10), the CPU 40 Issue an acceleration command. Conversely, when the actual rotational speed is faster than the target rotational speed, that is, when the internal clock counted between FG pulses is 9 pulses or less (9 pulses in FIG. 10), the CPU 40 Issue a deceleration command. By performing such speed feedback control, the rotational speed of the motor 39 can be controlled to a desired speed so that the internal clock counted between actual FG pulses becomes 10 pulses.

  The CPU 40 monitors the rotation speed during the rotation control of the motor 39, and rotates if the actual rotation speed detected from the FG signal has an error of a predetermined value or more with respect to the target rotation speed. It has an error detection function that detects speed abnormalities. In particular, in the rotational speed control of the motor that drives the process cartridge 5 involved in image formation, the rotational speed error range is about 3% or less so as not to disturb the image drawn on the photosensitive drum 1. Is set to If this error range is exceeded, it is detected as an abnormal rotation speed.

  Next, the flow of processing in the present embodiment will be described using the flowchart of FIG. This process is performed by the CPU 40.

  When the main body is turned on in step S1101 (step 1101 is abbreviated as S1101, the same applies hereinafter), it is determined in step S1102 whether or not the process cartridge 5 is new (corresponding to a new article detection unit in claims). This determination is made based on information indicating the use status in a non-illustrated nonvolatile memory attached to the process cartridge 5. If it is determined in S1102 that the process cartridge 5 is new, the CPU 40 sets the threshold value for detecting the speed abnormality of the motor 39 to a value for winding the toner seal (± 30% in this embodiment) in S1103, and in S1104. The motor 39 is started. The rotation of the motor 39 causes the toner seal 28 of the process cartridge 5 to be wound around the toner seal winding shaft 34 shown in FIG. Then, it is confirmed that the seal winding is completed in S1105 after a predetermined time has elapsed since the winding of the toner seal 28 is started. In step S1106, the CPU 40 sets the speed detection threshold value of the motor 39 to a value for image formation (in this embodiment, ± 3% <threshold value for toner seal winding), and a series of toner seal winding. The sequence ends. Thereafter, the main body performs an initial operation in S1107, and transitions to a standby state in S1108. At this time, if the power is not turned off in S1109 and there is a print instruction in S1110, a desired image forming operation is started in S1111. If a series of printing operations is completed in step S1112, the process returns to step S1108 and transitions to the standby state again.

  As described above, in this embodiment, the speed error range is set to ± 30%, which is the value for opening the toner container when the toner container is opened, and the value for opening the toner container is set during the image forming operation. The value is set to ± 3% which is a value for forming a small image. As a result, even if the rotational speed of the rotational drive source changes slightly due to the torque at the time of opening the sealing member of the toner container, the speed abnormality is not detected, so that the torque specifications of the rotational drive source can be reduced and cost merit can be obtained. It becomes possible.

A “color image forming apparatus” that is Embodiment 2 will be described. The present embodiment is almost the same as the configuration of the first embodiment, and only the method for detecting the completion of winding of the toner seal 28 is different. Then, about points other than the detection method of winding completion, description of Example 1 is used and description here is abbreviate | omitted.
The winding completion detection method in this embodiment is to count the number of FG pulses output from the motor 39 at the time of winding (equivalent to measurement of the number of pulses in the claims), and the actual load torque of the motor 39 FIG. 12 shows the relationship between the rotation speed and the number of FG pulses.
In FIG. 12, in this embodiment, the load torque applied to the motor 39 at the time of winding the seal is the torque transition shown in FIG. 16 (graph in FIG. 12 (lower)), and the rotation speed of the motor 39 at the time of winding the seal is The graph is as shown in FIG. 12 (middle). Here, as an example, it is described as a configuration in which the rotation speed of the motor 39 changes according to the load. At this time, the integrated value of the number of FG pulses output from the motor 39 changes as shown in the graph of FIG. As described above, since the number of FG pulses output from the motor 39 corresponds to the number of rotations of the rotor 58 of the motor 39, when the winding is actually completed from the number of motor rotations required to wind the toner seal 28. The number of FG pulses can be set by reverse calculation.

  Next, the flow of processing in the present embodiment will be described using the flowchart of FIG. This process is performed by the CPU 40. In FIG. 13, since the operation during standby and printing is the same as that in FIG. 11, only the operation during toner seal winding is described.

  When the power of the main body is turned on in S1301, it is determined in S1302 whether or not the process cartridge 5 is new. If it is determined in step S1302 that the process cartridge 5 is new, the CPU 40 sets the speed abnormality detection threshold of the motor 39 to a value for winding the toner seal in step S1303, and starts the motor 39 in step S1304. The rotation of the motor 39 causes the toner seal 28 of the process cartridge 5 to be wound around the toner seal winding shaft 34 shown in FIG. At this time, the CPU 40 counts the number of FG pulses output from the motor 39 in S1305, and determines that the winding is completed in S1307 when the count reaches a predetermined count number (a value at which winding can be completed) in S1306. . After that, in S1308, the CPU 40 sets the speed abnormality detection threshold of the motor 39 to a value for image formation (<threshold value for toner seal winding), and a series of toner seal winding sequences is completed.

  According to this embodiment, completion of toner seal winding can be detected in a shorter time than in the first embodiment.

  A “color image forming apparatus” that is Embodiment 3 will be described. The present embodiment is almost the same as the configuration of the first embodiment, and only the method for detecting the completion of winding of the toner seal 28 is different. Then, about points other than the detection method of winding completion, description of Example 1 is used and description here is abbreviate | omitted.

  In FIG. 14, as an example, the load torque applied to the motor 39 during winding of the seal is the torque transition shown in FIG. 16 (graph in FIG. 14 (lower)), and the rotation speed of the motor 39 during winding of the seal is as shown in FIG. It looks like the graph on the top. Here, as an example, it is described as a configuration in which the rotation speed of the motor 39 changes according to the load.

  In the present embodiment, as shown in FIG. 14 (upper stage), the winding completion detecting method samples the cycle of the FG pulse output from the motor 39 at a predetermined time interval T during winding, and starts the motor from that cycle. The rotational speed of 39 is calculated backward. Then, the rotational movement amount rotated during the sampling time T is calculated from the predetermined time interval T at which the CPU 40 samples the FG pulse and the rotational speed of the motor 39 calculated at that time (corresponding to the actual rotational speed in the claims). Then, the completion of winding is detected when the integrated value of the rotational movement amount calculated at each sampling reaches a predetermined value (a value at which winding can be completed). Note that the threshold value change for detecting an abnormality in the speed of the motor 39 is the same as that in FIG. 12, and is omitted in FIG.

Next, the flow of processing in this embodiment will be described with reference to the flowchart of FIG. This process is performed by the CPU 40. In FIG. 15, since the operation during standby and printing is the same as that in FIG. 11, only the operation during toner seal winding is described.
When the main body is turned on in S1501, it is determined in S1502 whether or not the process cartridge 5 is new. If it is determined in step S1502 that the process cartridge 5 is new, the CPU 40 sets the speed abnormality detection threshold value of the motor 39 to a value for winding the toner seal in step S1503, and starts the motor 39 in step S1504. The rotation of the motor 39 causes the toner seal 28 of the process cartridge 5 to be wound around the toner seal winding shaft 34 shown in FIG. At this time, after the sampling time T has elapsed in S1505, the CPU 40 detects the rotational speed of the motor 39 from the FG pulse period output by the motor 39 in S1506, and in S1507 the motor obtained from the sampling time T and the rotational speed of the motor 39 is obtained. The rotational movement amount of 39 is integrated. When the integrated value of the rotational movement amount of the motor 39 reaches a predetermined value (a value at which winding can be completed) in S1508, it is determined that winding is completed in S1509. After that, in S1510, the CPU 40 sets the threshold value for detecting the speed abnormality of the motor 39 to a value for image formation (<the threshold value value for winding the toner seal), and the series of toner seal winding sequences ends.

  According to the present embodiment, completion of toner seal winding can be detected in a shorter time than in the first embodiment.

Sectional drawing which shows schematic structure of the color image forming apparatus which is Example 1. FIG. Sectional drawing which shows schematic structure of the process cartridge in Example 1. FIG. FIG. 3 is a perspective view illustrating a configuration of a toner seal winding unit according to the first exemplary embodiment. The figure which shows the structure of the drive circuit of DC brushless motor in Example 1. FIG. The figure which shows the phase switching of the DC brushless motor in Example 1 Drive control block diagram of DC brushless motor in Embodiment 1 The figure which shows the FG pattern in Example 1. The figure which shows the positional relationship of the FG pattern and FG pattern magnet in Example 1. FIG. The figure which shows the FG signal in Example 1. The figure which shows the outline of the speed control in Example 1. Flowchart showing processing in the first embodiment. Operation explanatory diagram in Embodiment 2 Flowchart showing processing in the second embodiment. Operation explanatory diagram in Embodiment 3 Flowchart showing processing in the third embodiment. Figure showing an example of torque transition when winding the toner seal

Explanation of symbols

5 Process cartridge 23 Toner container 28 Toner seal 39 DC brushless motor 40 CPU
70 FG pattern 71 magnet

Claims (4)

In the image forming apparatus Luke cartridges is detachable having a toner container opening with a sealing member is sealed,
In a state in which the cartridge is mounted, a rotary drive source for driving the front hear cartridges,
And opening means for opening said sealing member with the driving force of said rotary driving source,
A new-product detection means the front is attached to the image forming apparatus asked cartridges detects whether new,
And abnormality detecting means you detect the rotation drive source of the rotating Utatekoto always when the rotational speed of the rotary driving source exceeds a first speed Dohan enclosed predetermined,
When the toner container by the new-product detection means detects that the new, by setting the first speed Dohan circumference to a second speed range for unsealing the toner container, the rotary drive source start to begin the opening sealing operation Ru good to said opening means, after the unsealing operation of the toner container is judged complete, and control means for switching from said second fast Dohan circumference in the first speed range ,
An image forming apparatus comprising: The image forming apparatus according to claim 1.
It said control means, the image forming apparatus, wherein said determine that the toner container opening operation is completed when the inter-start at the time of the previous KiHiraki sealing operation has elapsed. The image forming apparatus according to claim 1.
The rotary drive source drives the front hear cartridges, generates a pulse signal synchronized with the rotation operation,
Wherein, from the start of the previous KiHiraki sealing operation, the number of pulses of the pulse signal is measured, that the number of measured pulses is judged that the KiHiraki sealing operation upon reaching a predetermined number of pulses has been completed An image forming apparatus. The image forming apparatus according to claim 1.
Wherein, from the start of the previous KiHiraki sealing operation, the actual rotational speed of said rotary drive source to monitor a predetermined time interval your capital, the rotational movement of the rotary drive source from the actual rotational speed and the predetermined time interval of monitoring accumulating the amount of image forming apparatus and determines that front KiHiraki sealing operation is completed when the integrated the rotational movement amount has reached a predetermined rotational movement amount.

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