JP4235403B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a printer and a copying machine, and in particular, to realize both a stable first copy time and a long life of an image forming apparatus by accurately predicting a rise time of a polygon motor or the like. It is about.
[0002]
[Prior art]
In recent years, an electrophotographic image forming apparatus generally includes a copying machine as shown in FIG. A conventional image forming apparatus will be described with reference to FIG. Although not described in detail, 1R is a document reading unit for performing a document copying operation. Next, the image output unit 1P is roughly divided into an image forming unit 10 (four stations a, b, c, and d are arranged in parallel, and the configuration is the same), a paper feeding unit 20, an intermediate transfer unit. 30, a fixing unit 40 and a control unit (not shown).
[0003]
Further, each unit will be described in detail. The image forming unit 10 is configured as described below. Photosensitive drums 11a, 11b, 11c, and 11d as image carriers are pivotally supported at their centers and are driven to rotate in the direction of the arrow. The primary chargers 12a, 12b, 12c, and 12d, optical systems 13a, 13b, 13c, and 13d, and developing devices 14a, 14b, 14c, and 14d are arranged in the rotation direction facing the outer peripheral surfaces of the photosensitive drums 11a to 11d. Yes. In the primary chargers 12a to 12d, charges of a uniform charge amount are given to the surfaces of the photosensitive drums 11a to 11d. Next, the optical systems 13a to 13d expose the photosensitive drums 11a to 11d with light beams such as laser beams modulated according to the recording image signal, thereby forming electrostatic latent images thereon. Further, the electrostatic latent images are visualized by developing devices 14a to 14d that respectively store four color developers (toners) such as yellow, cyan, magenta, and black. On the downstream side of the image transfer areas Ta, Tb, Tc, and Td for transferring the visualized visible image to the intermediate transfer belt, the photosensitive drums 11a to 11d are not transferred to the transfer material by the cleaning devices 15a, 15b, 15c, and 15d. The toner remaining on 11d is scraped off to clean the drum surface. By the process described above, image formation with each toner is sequentially performed.
[0004]
The paper feed unit 20 includes cassettes 21a and 12b and a manual feed tray 27 for storing the recording material P, pickup rollers 22a, 22b and 26 for feeding the recording material P one by one in the cassette or from the manual feed tray, and each pickup roller. A pair of paper feed rollers 23 and a paper feed guide 24 for transporting the recording material P fed from 22a, 22b and 26 to the registration rollers, and the recording material P in the secondary transfer area in accordance with the image forming timing of the image forming unit. It consists of registration rollers 25a and 25b for feeding to Te.
[0005]
The intermediate transfer unit 30 will be described in detail. The intermediate transfer belt 31 (for example, PET [polyethylene terephthalate] or PVdF [polyvinylidene fluoride] is used as its material) is energized by a drive roller 32 that transmits driving to the intermediate transfer belt 31 and a spring (not shown). As a result, the intermediate transfer belt 31 is wound around a tension roller 33 that applies an appropriate tension, and a driven roller 34 that faces the secondary transfer region Te across the belt. Among these, a primary transfer plane A is formed between the driving roller 32 and the tension roller 33. The drive roller 32 is coated with rubber (urethane or chloroprene) having a thickness of several millimeters on the surface of the metal roller to prevent slippage with the belt. The drive roller 32 is rotationally driven by a pulse motor (not shown). Primary transfer blades 35 a to 35 d are disposed on the back of the intermediate transfer belt 31 in the primary transfer regions Ta to Td where the photosensitive drums 11 a to 11 d and the intermediate transfer belt 31 face each other. A secondary transfer roller 36 is disposed so as to face the driven roller 34, and a secondary transfer region Te is formed by a nip with the intermediate transfer belt 31. The secondary transfer roller 36 is pressed against the intermediate transfer belt with an appropriate pressure. A cleaning device 50 for cleaning the image forming surface of the intermediate transfer belt 31 is disposed on the intermediate transfer belt 31 and downstream of the secondary transfer region Te. The cleaning device 50 includes a cleaner blade 51 (as a material). And a waste toner box 52 for storing waste toner.
[0006]
The fixing unit 40 includes a fixing roller 41a having a heat source such as a halogen heater inside, a pressure roller 41b (this roller may also be provided with a heat source), and a transfer material to the nip portion of the roller pair. It comprises a guide 43 for guiding P, and an inner discharge roller 44 and an outer discharge roller 45 for further guiding the transfer material P discharged from the roller pair to the outside of the apparatus.
[0007]
The control unit includes a control board 70 for controlling the operation of the mechanism in each unit, a motor drive board (not shown), and the like.
[0008]
Next, a description will be added in accordance with the operation of the apparatus.
[0009]
When the image forming operation start signal is issued, first, the transfer material P is sent out one by one from the cassette 21a by the pickup roller 22a. The transfer material P is guided between the paper feed guides 24 by the paper feed roller pair 23 and is conveyed to the registration rollers 25a and 25b. At that time, the registration rollers 25a and 25b are stopped, and the leading edge of the paper hits the nip portion. Thereafter, the registration rollers 25a and 25b start rotating in accordance with the timing at which the image forming unit starts to form an image. The rotation timing is set so that the transfer material P and the toner image primarily transferred onto the intermediate transfer belt 31 from the image forming portion exactly coincide with each other in the secondary transfer region Te.
[0010]
On the other hand, in the image forming unit, when an image forming operation start signal is issued, a high voltage is applied to the toner image formed on the photosensitive drum 11d that is the most upstream in the rotation direction of the intermediate transfer belt 31 by the process described above. Further, primary transfer is performed on the intermediate transfer belt 31 in the primary transfer region Td by the primary transfer charger 35d. The primarily transferred toner image is conveyed to the next primary transfer region Tc. In this case, image formation is performed with a delay by the time during which the toner image is conveyed between the image forming portions, and the next toner image is transferred with the resist aligned on the previous image. Thereafter, the same process is repeated, and eventually the four color toner images are primarily transferred onto the intermediate transfer belt 31.
[0011]
Thereafter, when the recording material P enters the secondary transfer region Te and contacts the intermediate transfer belt 31, a high voltage is applied to the secondary transfer roller 36 in accordance with the passing timing of the recording material P. Then, the four color toner images formed on the intermediate transfer belt 31 by the process described above are transferred onto the surface of the recording material P. Thereafter, the recording material P is accurately guided to the fixing roller nip portion by the conveyance guide 43. The toner image is fixed on the surface of the recording material by the heat of the roller pairs 41a and 41b and the pressure of the nip. Thereafter, the recording material is conveyed by inner and outer paper discharge rollers 44 and 45, and the recording material is discharged outside the apparatus.
[0012]
In such an image forming apparatus, normally, as a preparatory operation of the image forming unit, the photosensitive drums (11a, 11b, 11c, 11d) are prepared for rotation, the optical systems (13a, 13b, 13c, 13d) are prepared for exposure start, and the developing device. When all the development start preparations (14a, 14b, 14c, 14d) are completed, an image forming operation can be performed.
[0013]
However, in recent copying machines, at the same time as realizing high productivity, reducing the time until the first copy is ejected, the so-called first copy time, has become a major issue. Control that is performed in parallel and reduces the preparation time until the start of the image forming operation is becoming common. For example, in the example of FIG. 1, the exposure start preparation of the optical system (13a, 13b, 13c, 13d) corresponds to the completion of the startup of the polygon motor, and takes the longest time among the three preparation operations. Next, the development start preparation of the developing devices (14a, 14b, 14c, 14d) corresponds to the rise of an image forming high voltage (also referred to as a developing high voltage) applied to the photosensitive drums (11a, 11b, 11c, 11d). If the photosensitive drums (11a, 11b, 11c, 11d) are not ready for rotation, it cannot be started.
[0014]
Therefore, first, the startup of the photosensitive drums (11a, 11b, 11c, 11d) and the startup of the polygon motor are performed in parallel, and after the photosensitive drum has started up, control for starting up the image forming high voltage may be performed. . In addition, if the state in which the image forming high voltage is raised is continued for a long time, the life of the photosensitive drum is greatly affected. Therefore, the polygon motor is preliminarily activated in advance for the timing to raise the image forming high voltage. Thus, it has been proposed to measure the time required to start up the polygon motor and perform control to match the start-up completion timing of the imaging high voltage with the start-up completion timing of the polygon motor.
[0015]
[Problems to be solved by the invention]
However, in the control as described above, the rise time of the polygon motor greatly affects the temperature rise in the apparatus of the image forming apparatus. Therefore, in order to know the accurate preparation time of the polygon motor, immediately before the image forming operation, It was necessary to start up the polygon motor frequently, and there were problems such as a decrease in the life of the polygon motor. On the other hand, if the polygon motor is started up less frequently in order to know the operation preparation time, the polygon motor rise time during the image forming operation will be different from the measured rise time of the polygon motor. However, when the rise time of the polygon motor during image formation took a long time, the rise control of the polygon motor was completed before the polygon motor shifted to steady rotation, and the polygon motor did not reach steady rotation within a certain time. There was a problem that an error occurred.
[0016]
Further, since it is directly related to the increase in the first copy time that the estimated rise time of the polygon motor is unnecessarily long, it is difficult to determine the estimated rise time of the polygon motor.
[0017]
The present invention has been made under these circumstances, without pre-rotation of the polygon motor, and an object thereof is to provide an image forming equipment which can obtain an accurate determination of the exposure ready Is.
[0018]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, an image forming apparatus is configured as described in (1 ) below.
(1) and composed of an exposure apparatus of the polygon motor and the laser exposure unit, and an imaging device for creating a toner image based on a latent image formed on the photosensitive member by the exposure device, transferring the toner image In an image forming apparatus that prints an image on a transfer material by fixing to the material,
A polygon motor scheduled startup time table showing a relationship between a schedule time required for startup of the polygon motor from the start of the polygon motor startup operation to completion of the startup operation and the temperature of the image forming apparatus. Having storage means;
An elapsed time measuring means for measuring an elapsed time from the start- up operation of the polygon motor ;
Temperature detecting means for detecting the temperature of the image forming apparatus;
An operation completion detecting means for detecting the completion of the start-up operation of the polygon motor,
Based on the temperature in the image forming apparatus immediately before starting the startup of the polygon motor detected by the temperature detection means, the required startup time is determined based on the polygon motor startup time table. when elapsed time measured by said elapsed time measuring means, consistent with a time obtained by subtracting the start-up time of the image forming high voltage to be applied to the photoreceptor from the predetermined start-up expected time, and the imaging When the elapsed time measured by the elapsed time measuring means has elapsed by the required scheduled startup time, the operation completion detection means detects completion of the polygon motor startup operation. If it is determined that the polygon motor start-up operation has been completed, the operation completion detecting means determines that the polygon motor start-up operation has been completed. If you have not been detected, and a control means for determining the completion of the start-up operation of the polygon motor when it detects the completion of the start-up operation of the polygon motor by then the operation completion detecting means,
An image forming apparatus.
[0041]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to examples of image forming apparatuses. The present invention is not limited to the form of the apparatus, and can be implemented in the form of a method supported by the description of the embodiments.
[0042]
【Example】
Example 1
The configuration of the “image forming apparatus” according to the first embodiment is the same as the configuration of FIG. 1 used for the description of the conventional example, and thus the description thereof is used and the description thereof is omitted here. The same members as those in the conventional example are denoted by the same reference numerals.
[0043]
FIG. 2 is a block diagram illustrating a configuration of a control controller that controls the image forming apparatus according to the present exemplary embodiment, and includes a CPU 201, an image reader control unit 202, an image signal control unit 203, a printer control unit 204, a ROM 205, a RAM 206, and an operation panel. The control unit 207 is configured. The CPU 201 controls the document reading unit 1 </ b> R through the reader control unit 202 by executing a program stored in the ROM 205. The image signal control unit 203 accumulates image data of a document read from the document reading unit 1R or image data input to the image signal control unit via a network, and outputs print data to the printer control unit 204. The CPU 201 controls an operation panel (not shown) via the operation panel control unit 207. 208 is an A / D converter, and 209 is a temperature sensor. Although not shown in FIG. 1, the temperature sensor 209 can measure the temperature inside the image forming apparatus. The CPU 201 measures the temperature in the image forming apparatus by converting the output value of the temperature sensor 209 into digital data through the A / D converter 208.
[0044]
FIG. 3 is a diagram describing the area allocation of the ROM 205 and the RAM 206. A ROM 301 includes an area 303 in which a program is stored, an area 304 in which defined parameters are stored, and a polygon motor start-up time prediction table 305 described later. A RAM 302 includes a stack area 306 and a variable area 307 necessary for program execution.
[0045]
FIG. 4 is a diagram showing a correlation characteristic between the temperature in the image forming apparatus detected by the temperature sensor 209 and the time required for completion of startup of the polygon motor (corresponding to the estimated exposure preparation completion time in the claims). As indicated by the graph 401, the polygon motor takes a long time to start up when the temperature in the image forming apparatus is lower than 50 ° C. Also, when the temperature reaches 90 ° C. or higher, the time required for starting up the polygon motor becomes longer. 402 is an approximation of the graph 401 to a table. For example, if the output of the temperature sensor is 40 ° C. or higher and lower than 50 ° C., the rise time of the polygon motor can be predicted to be 4.0 seconds. The table 402 is stored in the start-up table 305 shown in FIG. 3, and the CPU 201 refers to the table for predicting the start-up time of the polygon motor.
[0046]
If there is a correlation characteristic between the environmental humidity and the rise time of the polygon motor, the characteristic may be examined in advance and stored in a table and referred to when the polygon motor start-up time is predicted. Also, the table 402 in FIG. 4 may be used for the monochrome image forming mode, and a predetermined value may be added to each value of this table in the color image forming mode to be used for the polygon motor startup prediction. This is because in general, the color mode requires a longer polygon motor rise time than the monochrome mode.
[0047]
FIG. 5 is a subroutine showing the image forming preparation operation in this embodiment. When the CPU 201 receives the print start command, first, the temperature sensor 209 samples the temperature in the image forming apparatus (see step 502 (denoted as S502 in the figure), and so on). Next, from Table 402, the time Tp required to start up the polygon motor is obtained from the sampling temperature (step 503). Next, in step 504, a time Tk required to raise the image forming high voltage is obtained. Next, in step 505, the polygon motor is started to drive. Although not specifically illustrated, the polygon motor starts up only the polygon motor of the black optical system (13d) when the print job is monochrome, and the polygon motor of all the optical systems (13a to 13d) when the print job is color. Start up the motor. Next, at step 506, a counter T1 that measures the elapsed time since the start-up of the polygon motor is started is initialized. Subsequently, in step 507, driving of the photosensitive drums (11a to 11d), the developing devices (14a to 14d), and the intermediate transfer belt 31 is started. When the counter T1 is counted up and the counter value has elapsed by the time obtained by subtracting the imaging high voltage startup time Tk from the estimated polygon startup time Tp (steps 508 and 509), the imaging high voltage is increased in step 510. Start to raise. Next, in step 511, the counter T1 is further counted up. When the counter value becomes equal to the estimated polygon start-up time Tp, the image forming preparation operation is completed, and the subroutine is ended (step 513).
[0048]
FIG. 6 is a timing chart showing the image formation preparation operation described in FIG. When a print start command is input at 602, the print preparation state is changed from the print stop state. In the print preparation state, in 603, the polygon motor changes from the stopped state to the rising state, and at 604, the photosensitive drum, the developing device, and the intermediate transfer belt change from the stopped state to the rising state. As shown in FIG. 5, when (Tp−Tk) time elapses after the polygon motor start-up, the image formation high voltage starts to start up from the stop at 605. The image forming high voltage rises at Tk time, and at the same time, the polygon motor also rises at Tp time from the start of start-up. Therefore, after Tp time, it is possible to shift from the image formation preparation stage to the image formable stage as indicated by 601.
[0049]
Since the exposure preparation time may vary depending on the image formation mode, one of the exposure preparation times may be selected as the exposure preparation time according to the image formation mode when starting the exposure preparation.
[0050]
As described above, in this embodiment, paying attention to the fact that the rise time of the polygon motor has a correlation with the temperature inside the image forming apparatus, the inside temperature of the image forming apparatus and the estimated rise time of the polygon motor are calculated. By preparing the table shown in advance in the control unit of the image forming apparatus and obtaining the optimum estimated polygon motor rise time from the internal temperature measured immediately before the image forming operation preparation operation based on the table, It is possible to achieve control that matches the voltage rise completion timing and the polygon motor rise completion timing, and it is possible to complete image formation preparation at the optimal timing in response to the changing rise time of the polygon motor. become.
[0051]
(Example 2)
Since the configuration of the “image forming apparatus” according to the second embodiment is the same as the configuration of FIG. 1 used for the description of the conventional example, the description thereof is incorporated and the description thereof is omitted here. The same members as those in the conventional example are denoted by the same reference numerals.
[0052]
FIG. 7 is a block diagram illustrating a configuration of a control controller that controls the image forming apparatus according to the present exemplary embodiment. The CPU 701, the image reader control unit 702, the image signal control unit 703, the printer control unit 704, the ROM 705, the RAM 706, and an operation panel are illustrated. The control unit 707 is configured. The CPU 701 controls the document reading unit 1 </ b> R through the reader control unit 702 by executing a program stored in the ROM 705. The image signal control unit 703 accumulates the image data of the document read from the document reading unit 1R or the image data input to the image signal control unit 703 via the network, and outputs the print data to the printer control unit 704. . The CPU 701 controls an operation panel (not shown) via the operation panel control unit 707. Reference numeral 708 denotes an A / D converter, and reference numeral 709 denotes a temperature sensor.
[0053]
Although not shown in FIG. 1, the temperature sensor 709 can measure the temperature inside the image forming apparatus. The CPU 701 measures the temperature in the image forming apparatus by converting the output value of the temperature sensor 709 into digital data through the A / D converter 708. Reference numeral 710 denotes a polygon motor control register, and 711 denotes a polygon motor. The CPU 701 can not only drive the polygon motor 711 by operating the polygon motor control register 710 but also monitor the register 710 whether or not the rising of the polygon motor has been completed.
[0054]
The configurations of the ROM 705 and the RAM 706 are the same as those in FIG. The relationship between the temperature sensor, the output value of 709 and the estimated startup time of the polygon motor is the same as in FIG.
[0055]
FIG. 8 is a subroutine showing the image forming preparation operation in this embodiment. When the CPU 701 receives the print start command, the temperature sensor 709 first samples the temperature in the image forming apparatus (step 802). Next, from Table 402, the time Tp required to start up the polygon motor is obtained from the sampling temperature (step 803). Next, in step 804, a time Tk required to raise the image forming high voltage is obtained. Next, in step 805, the polygon motor is driven to start. Although not specifically illustrated, the polygon motor starts up only the polygon motor of the black optical system (13d) when the print job is monochrome, and the polygon motor of all the optical systems (13a to 13d) when the print job is color. Start up the motor. Next, in step 806, a counter T1 that measures the elapsed time since the start-up of the polygon motor is started is initialized. In step 807, driving of the photosensitive drums (11a to 11d), the developing devices (14a to 14d), and the intermediate transfer belt 31 is started. When the counter T1 is counted up and the value of the counter has elapsed by the time obtained by subtracting the imaging high voltage startup time Tk from the estimated polygon startup time Tp (steps 808 and 809), the imaging high voltage is increased in step 810. Start raising. Next, at step 811, the counter T1 is further counted up. When the value of the counter becomes equal to the estimated polygon startup time Tp (step 812), the polygon motor control register 710 monitors whether the polygon motor 711 has started up (step 812). 813) When the rising of the polygon motor 711 is completed, the image forming preparation operation is completed, and the subroutine is ended (817). On the other hand, when the polygon motor 711 is not started up, the count T1 is further counted up, and when the counter exceeds the counter Terr which is determined to be a polygon motor abnormal error, NG is returned to urgently stop the image formation preparation operation. Then, the subroutine is finished (steps 815 and 816).
[0056]
FIG. 9 is a timing chart showing an example of the image formation preparation operation described in FIG. When a print start command is input in 902, the print preparation state is changed from the print stop state. In the print preparation state, in 903, the polygon motor changes from the stopped state to the rising state, and in 904, the photosensitive drum, the developing device, and the intermediate transfer belt change from the stopped state to the rising state. As shown in FIG. 8, when (Tp−Tk) time elapses from the start of polygon motor start-up, the image formation high voltage starts to start from stop at 905. Although the image forming high voltage rises at time Tk, if the polygon motor has not yet risen at this time, the rise monitoring of the polygon motor by the register 710 is started. When the rising edge (lock signal) of the polygon motor is detected, it is possible to shift from the image formation preparation stage to the image formation ready stage as indicated by reference numeral 901.
[0057]
As described above, according to this embodiment, when the polygon motor does not reach steady rotation within the estimated rise time of the polygon motor, the rise completion signal indicating the completion of the rise of the polygon motor indicates that the rise is completed. By monitoring the completion of the polygon motor start-up, it is possible to reliably realize the control to match the start-up timing of the imaging high voltage and the start-up completion timing of the polygon motor. It becomes possible to make it.
[0058]
【The invention's effect】
As described above, according to the first aspect of the present invention, preparation for image formation is completed at an optimal timing without preliminary rotation of the polygon motor and corresponding to the rising time of the changing polygon motor. Can be made. Further, even if the rise of the port Rigonmota took longer than the expected rise time, by Rio monitoring rising of the polygon motor, can be completed reliably image forming preparation.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an image forming apparatus (copier). FIG. 2 is a diagram showing a configuration of a controller in Embodiment 1. FIG. 3 is a diagram showing allocation of ROM and RAM areas. FIG. 5 is a flowchart showing the relationship between start-up time and temperature sensor output. FIG. 5 is a flowchart showing processing of image formation preparation operation in Embodiment 1. FIG. 6 is a timing chart of image formation preparation operation in Embodiment 1. FIG. FIG. 8 is a flowchart showing the process of image formation preparation operation in the second embodiment. FIG. 9 is a timing chart of image formation preparation operation in the second embodiment.
201 CPU
205 ROM
206 RAM
305 Startup time table

Claims (1)

Comprising a composed exposure apparatus from the polygon motor and the laser exposure unit, and an imaging device for creating a toner image based on a latent image formed on the photosensitive member by the exposure device, fixing the toner image to a transfer material In an image forming apparatus that prints an image on a transfer material by
A polygon motor scheduled startup time table showing a relationship between a schedule time required for startup of the polygon motor from the start of the polygon motor startup operation to completion of the startup operation and the temperature of the image forming apparatus. Having storage means;
An elapsed time measuring means for measuring an elapsed time from the start- up operation of the polygon motor ;
Temperature detecting means for detecting the temperature of the image forming apparatus;
An operation completion detecting means for detecting the completion of the start-up operation of the polygon motor,
Based on the temperature in the image forming apparatus immediately before starting the startup of the polygon motor detected by the temperature detection means, the required startup time is determined based on the polygon motor startup time table. the elapsed time measured by the elapsed time measuring means, when they match a time obtained by subtracting the start-up time of the image forming high voltage to be applied to the photoreceptor from the predetermined start-up expected time, the image forming and When the elapsed time measured by the elapsed time measuring means has elapsed by the required scheduled startup time, the operation completion detection means detects completion of the polygon motor startup operation. If it is determined that the polygon motor start-up operation has been completed, the operation completion detecting means determines whether the polygon motor start-up operation has been completed. If not detected completion includes a control means for determining the completion of the start-up operation of the polygon motor when it detects the completion of the start-up operation of the polygon motor by then the operation completion detecting means,
An image forming apparatus comprising:

Images