JP6044690B2 - Print control method - Google Patents

Description

The present invention relates to a printing control method, a print control method of the tandem type of the printing apparatus, especially using the electrophotographic method.

  A tandem type printing apparatus using an electrophotographic system uses, for example, yellow (Y), magenta (M), cyan (C), and black (K) image forming units, and each image forming unit has a photoconductor. A motor for rotating the drum is used. As this motor, for example, a stepping motor that is easy to control is used, and a rotating body such as a photosensitive drum in each image forming unit is driven.

  FIG. 30 is a diagram for explaining drive control of a stepping motor used in each of the image forming units. The example shown in the figure shows an example of an image forming unit of four colors, for example, yellow (Y), magenta (M), cyan (C), and black (K), and 0.2f (for example, f is 1000) μsec reference clock (SysClk) is used to set the motor drive timing for driving the photosensitive drum in each image forming unit. As shown in the figure, the conventional drive timing is driven at the same timing in all stepping motors used in each image forming unit.

  Patent Document 1 is an invention related to an intermediate transfer device using a stepping motor. In order to adjust a roller gap, the speed of a conveying roller system is calculated based on an encoder signal, and the stepping motor is corrected based on the calculation result. A command is sent to adjust the gap by changing the number of drive steps.

  Patent Document 2 is an invention that corrects rotation unevenness of a transfer belt driven by using a stepping motor to reduce color misregistration and pitch unevenness of a color image, and is a roller different from a drive roller for the transfer belt. The rotation speed is detected to detect the reference position, and the rotation of the drive roller is controlled based on the reference position.

JP 2010-055069 A JP 2007-52111 A

  However, the conventional stepping motors are driven at the same timing for all stepping motors used in each image forming unit as described above. For this reason, resonance vibration caused by the driving of the stepping motor occurs, and the quality of the printed image decreases. FIG. 31 is a diagram illustrating an example of resonance vibration caused by driving of each stepping motor, and FIG. 32 is a diagram illustrating a combined wave of the resonance vibration. Further, FIG. 33 shows the result of Fourier analysis of the synthesized wave. For example, jitter based on resonance vibration occurs at a specific frequency of 0.5 f (for example, f is 1000 Hz).

  Accordingly, the image forming unit vibrates at a specific frequency due to the resonance vibration of the stepping motor, for example, the print positions of yellow (Y), magenta (M), cyan (C), and black (K) are shifted, and the quality of the color image Decreases. In addition to driving the motor, jitter is generated due to a gear for transmitting the driving force of the motor to a rotating body such as a photosensitive drum, and image quality is deteriorated.

SUMMARY An advantage of some aspects of the invention is that it provides a print control method that reduces jitter vibration caused by motor driving, gear rotation, and the like, and improves the quality of a printed image.

The printing control method according to the present invention includes a process of driving a rotation mechanism having a gear by a motor;
A process of changing the driving phase of the motor when driving the motor, a process of changing a current value supplied to the motor, and a process of Fourier transforming data when a patch pattern is read by a predetermined reading device; And a process of deriving a period value of jitter caused by driving of the motor or rotation of the gear based on a result obtained by the Fourier transform, and the derived period value of jitter is If it is a period value of jitter caused by driving, the drive phase is changed , and if the derived jitter period value is a jitter period value resulting from gear rotation, the current value is changed . It is characterized by performing .
In another printing control method according to the present invention, a process of driving a rotation mechanism having a gear by a motor, a process of changing a driving phase of the motor when driving the motor, and a current supplied to the motor Based on the process obtained by changing the value, the process of changing the rotational speed of the motor, the process of Fourier transforming data when the patch pattern is read by a predetermined reader, and the result obtained by the Fourier transform, A process of deriving a period value of jitter due to the driving of the motor or the rotation of the gear, and when the derived period value of the jitter is a period value of jitter due to the driving of the motor, to change the drive phase, when the period value of the derived the jitter is a periodic value of the jitter caused by the rotation of the gear, varying changes or the rotational speed of the current value Performing, characterized in that.
In another printing control method according to the present invention, a process of driving a rotation mechanism having a gear by a motor, a process of changing a driving phase of the motor when driving the motor, and a current supplied to the motor Based on the process obtained by changing the value, the process of changing the rotational speed of the motor, the process of Fourier transforming data when the patch pattern is read by a predetermined reader, and the result obtained by the Fourier transform, A process of deriving a period value of jitter due to the driving of the motor or the rotation of the gear, and when the derived period value of the jitter is a period value of jitter due to the driving of the motor, to change the drive phase, when the period value of the derived the jitter is a periodic value of the jitter caused by the rotation of the gear, the change of the current value and the change of the rotational speed Carried out, characterized in that.

  According to the present invention, it is possible to reduce the occurrence of jitter caused by a motor disposed in each image forming unit and a motor that drives a rotation mechanism such as a motor that drives a transfer belt, and further transmits the driving of the motor. It is possible to reduce the occurrence of jitter due to the rotation of the gear.

It is a figure explaining the control system of the printing apparatus of this embodiment. It is a figure which shows the example of a color printing apparatus as a printing apparatus of this embodiment, for example. FIG. 3 is a perspective view of an intermediate transfer belt unit and includes a sensor arrangement provided in the vicinity of the intermediate transfer belt unit. It is a figure explaining the control system of a printing apparatus. It is a figure which shows the state by which the patch pattern was transcribe | transferred to the transfer belt. It is a figure which shows the example of the patch pattern detected when the patch row | line passed the sensor vicinity. It is another example of a patch pattern, and is a figure which shows an example in case the character dropout phenomenon generate | occur | produces. It is a figure which shows the analysis result obtained by Fourier-transforming the data detected by the density sensor. It is a figure which shows the conditions of an analysis result. It is a figure which shows the relationship between the detection result by a density sensor, and the jitter period obtained by the said calculation formula. It is a figure explaining the specific structure of the drum unit containing a developing device. It is a figure which shows the number of teeth of a kit motor pinion gear and a drum gear, and the feed amount per tooth. It is a figure explaining the specific structure of the belt drive mechanism containing a transfer belt. It is a figure which shows the number of teeth of a belt gear, and the feed amount per tooth. It is a figure which shows the output timing of the clock signal in the case of driving a kit motor by four colors and two phases using a reference clock of 0.2f. It is a wave form diagram of resonance vibration resulting from the drive of a stepping motor. It is a wave form diagram of the synthetic wave of resonance vibration. It is a figure which shows the result of having carried out the Fourier-transform of the synthetic wave of a resonance vibration. It is a figure which shows the processing method of jitter vibration. It is a figure which shows the output timing of the clock signal in the case of driving a kit motor by 4 colors and 4 phases. It is a figure which shows the example which the resonance vibration resulting from the drive of a stepping motor generate | occur | produces a little. It is a wave form diagram of the synthetic wave of the resonance vibration generated a little. It is a figure which shows the result of having carried out the Fourier-transform of the synthetic wave of resonance vibration, and shows that a jitter hardly generate | occur | produces in a synthetic wave. It is a time chart explaining the specific method of phase switching. It is a flowchart explaining the specific method of phase switching. It is another time chart explaining the specific method of phase switching. It is another flowchart explaining the specific method of phase switching. It is a figure referred when examining the cause of the occurrence of jitter based on the jitter cycle detected by the density sensor. It is a time chart which shows the example of a specific drive of a driver. It is a figure explaining the drive control of the conventional stepping motor. It is a figure which shows the example of the resonant vibration resulting from the drive of the conventional stepping motor. It is a figure which shows the synthetic wave of the conventional resonance vibration. It is a figure which shows the result of having carried out the Fourier analysis of the synthetic wave of the conventional resonance vibration.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 2 shows an example of a color printing apparatus (hereinafter simply referred to as a printing apparatus) as the printing apparatus of this embodiment. The printing apparatus 1 according to the present embodiment is a tandem type printing apparatus using an electrophotographic method, and includes an image forming unit 2, an intermediate transfer belt unit 3, a paper feeding unit 4, and a duplex printing conveyance unit 5. Has been.

  The image forming unit 2 has a configuration in which four image forming units 6 (6Y, 6M, 6C, and 6K) are arranged in a multistage manner from right to left in FIG. Of the four image forming units 6, the three upstream image forming units 6Y, 6M, and 6C (yellow (Y), magenta (M), and cyan (subtractive colors) are the three subtractive colors. A color image is formed using the color toner C), and the image forming unit 6K forms a monochrome image mainly using the black (K) toner used for the dark portion or characters of the image.

  Each of the image forming units 6 has the same configuration except for the color of the toner stored in the toner container (toner cartridge). Accordingly, the configuration of the black (K) image forming unit 6K will be described below as an example.

  The image forming unit 6 includes a photosensitive drum 7 at the bottom. The peripheral surface of the photosensitive drum 7 is made of, for example, an organic photoconductive material. A cleaner 8, a charging roller 9, a print head 10, and a developing roller 12 of a developing device 11 are arranged around the periphery of the photosensitive drum 7.

  The developing unit 11 stores toners of corresponding colors among Y, M, C, and K (yellow (Y), magenta (M), cyan (C), and black (K)) shown in the toner container of FIG. The intermediate portion is provided with a toner replenishing mechanism for the lower portion.

  The developing unit 11 is provided with the developing roller 12 at the side opening at the lower part of the developing unit 11. The toner stirring member, the toner supply roller for supplying toner to the developing roller 12, and the toner layer on the developing roller 12 are fixed. A doctor blade that regulates the layer thickness is provided.

  The intermediate transfer belt unit 3 has an endless transfer belt 14 extending in a flat loop shape from substantially the left and right sides of the figure at the approximate center of the main unit, and the transfer belt 14 is stretched over the transfer belt 14. A driving roller 15 and a driven roller 16 are provided to circulate and move the belt 14 counterclockwise in the figure.

  A toner image based on the print data is transferred to the transfer belt 14 (primary transfer), and the toner image is transported to a transfer position to the paper for further transfer (secondary transfer) to the paper. Further, a toner image (patch image) of a patch pattern described later is transferred to the transfer belt 14, and information is read from the patch pattern by a density sensor 35a described later.

  The intermediate transfer belt unit 3 includes a belt position control mechanism 17 in the loop of the flat loop-shaped transfer belt 14. The belt position control mechanism 17 includes a primary transfer roller 18 made of a conductive foam sponge that presses against the lower peripheral surface of the photosensitive drum 7 via the transfer belt 14.

  In the intermediate transfer belt unit 3, a belt cleaner unit 19 is disposed further upstream of the uppermost image forming unit 6Y on the upstream side in the belt movement direction, and is flat and thin so as to be almost along the entire bottom surface. The waste toner collecting container 20 is detachably disposed.

  The paper feeding unit 4 includes three paper feeding cassettes 21a, 21b, and 21c arranged in three stages, upper, middle, and lower, and the three paper feeding cassettes 21a, 21b, and 21c accommodate sheets (not shown). Has been.

  Sheet take-out rollers 22 are arranged in the vicinity of the sheet feed opening (right side in the figure) of the three sheet feed cassettes. In addition, a secondary transfer roller 24 that is in pressure contact with the driven roller 16 via the transfer belt 14 is disposed in the paper conveyance direction (vertical upward direction in the figure) of the standby conveyance roller pair 23 to perform secondary transfer onto the paper. Forming part.

  A belt fixing device 25 is disposed on the downstream side (upward in the drawing) of the secondary transfer portion, and on the further downstream side of the belt-type fixing device 25, a carry-out roller for carrying out the fixed sheet from the belt-type fixing device 25. A pair 26 and a paper discharge roller pair 28 for discharging the conveyed paper to a paper discharge tray 27 formed on the upper surface of the apparatus are provided.

  The duplex printing conveyance unit 5 includes a start return path 30 that branches from the intermediate conveyance path between the carry-out roller pair 26 and the discharge roller pair 28 to the right in the figure, an intermediate return path 31 that bends downward, and further. A terminal return path 32 is provided which bends in the left lateral direction opposite to the above and finally reverses the return sheet. In addition, the exit of the end return path 32 communicates with a conveyance path to the standby conveyance roller pair 33 corresponding to the sheet feeding cassette below the sheet feeding unit 4.

  In the printing apparatus 1 configured as described above, the image forming unit 6 is driven by the kit motor 34 provided for each color image forming unit 6Y, 6M, 6C, 6K. The arrangement positions of the kit motors 34Y, 34M, 34C, 34K provided in the image forming units 6Y, 6M, 6C, 6K will be described later.

  The kit motors 34Y, 34M, 34C, and 34K in the image forming units 6Y, 6M, 6C, and 6K are driving sources that rotationally drive the photosensitive drum 7 and the rotating body such as the developing roller 12 in the corresponding unit. . Further, the transmission of the rotational force to the rotating body such as the photosensitive drum 7 and the developing roller 12 corresponding to each kit motor 34Y, 34M, 34C, 34K is performed through a plurality of gears described later. Accordingly, the load characteristics of the kit motors 34Y, 34M, 34C, and 34K vary depending on the transmission system error such as the gear, the number of gear teeth, the gear ratio, and the like.

  On the other hand, FIG. 3 is a perspective view of the intermediate transfer belt unit 3 and includes an arrangement configuration of sensors provided in the vicinity of the intermediate transfer belt unit 3. As described above, the transfer belt 14 is looped over the drive roller 15 and the driven roller 16 that circulate in a counterclockwise direction. In the vicinity of the peripheral surface of the transfer belt 14, a density sensor 35a and a theta (θ) sensor 35b are provided. It is arranged.

  A patch pattern, which will be described later, is transferred onto the transfer belt 14, and this patch pattern is read by the density sensor 35a or the like and used for the processing of this example which will be described later.

  The drive roller 15 is driven by a belt motor described later, and the drive control of the belt motor is performed by a motor controller unit described later.

  FIG. 4 is a diagram illustrating a control system for the printing apparatus 1 having the above-described mechanism configuration. In FIG. 1, the printing apparatus 1 includes an interface controller (hereinafter referred to as an I / F controller) 13a and an engine control unit 13b. The I / F controller 13a includes a reception control unit 36, a ROM 37, a font ROM 38, and a display control unit. 39, a video I / F control unit 40, a memory 41 (standard RAM 41a, expansion RAM 41b), a compression / decompression control unit 42, and an MPU 43.

  On the other hand, the engine control unit 13b includes an engine controller unit 45, a motor controller unit 46, an MPU 47, a fixing control unit 48, and a high-pressure control unit 49. The engine controller unit 45 transmits video data to the print head 10, and the motor controller The unit 46 supplies a motor drive signal to the aforementioned kit motors 34Y, 34M, 34C, 34K, a belt motor, and the like. Further, the engine control unit 13b supplies drive signals to various loads and receives detection signals from various sensors such as the density sensor 35a and theta (θ) sensor 35b.

  Further, the MPU 47 receives information on the detected temperature of the fixing roller from, for example, a fixing thermistor 54 installed in the belt type fixing device 25, and the fixing control unit 48 controls the temperature of the fixing heater 55 installed in the belt type fixing device 25. Output a signal. Further, the high voltage control unit 49 outputs a high voltage control signal to the high voltage unit 56.

  The printing apparatus 1 having the above configuration is supplied with print data from a host device 69 such as a personal computer (PC) or a printer server via a Centronics interface and a LAN (local area network). The print data supplied from the host device 69 is transferred to the reception control unit 36. When a predetermined amount of print data is transferred to the reception control unit 36, the print data is transferred to the memory 41 (for example, the standard RAM 41a). The The print data transferred to the memory 41 is analyzed according to the control of the MPU 43, compressed and expanded by the compression / decompression control unit 42, and then sent from the video I / F control unit 40 to the engine control unit 13b. Is output.

  FIG. 1 is a diagram illustrating the configuration of the engine control unit 13b in detail. As described above, the engine control unit 13b includes the engine controller unit 45 and the motor controller unit 46. In FIG. 1, the configuration of the MPU 47, the fixing controller 48, and the high voltage controller 49 described above is omitted. In the figure, the video I / F control unit 40 will be described as being included in the engine control unit 13b for the sake of explanation.

  The engine controller unit 45 includes a head I / F control unit 60, a motor clock generation unit 61, a sensor drive circuit 62, a basic timing generation unit 63, and a CPU I / F unit 64. The video I / F control unit 40 is connected to a video RAM 40a for storing video data generated by the I / F controller 35.

  The head I / F control unit 60 includes a dot pattern generation unit 65, a head data transmission unit 66, a head control signal generation unit 67, and a strobe signal generation unit 68. The dot pattern generation unit 65 is transmitted from the video I / F control unit 40. Based on each gradation value, data in which one pixel of the supplied video data is developed into N fine pixels using the line buffer 65a is generated.

  The head data transmission unit 66 transfers the data generated by the dot pattern generation unit 65 to the print head 10 in synchronization with the dot clock (DCLK) output from the head control signal generation unit 67. The head control signal generator 67 outputs a horizontal synchronization signal (HSYNC) in addition to the dot clock (DCLK).

  Further, the strobe signal generation unit 68 divides the sub-scanning direction into n according to the gradation information set by the CPU I / F unit 64, and transmits the corresponding strobe signal to the print head 10. For example, when the sub-scanning direction is divided into three, three types of strobe signals (1/3), (2/3), and (3/3) are output. When the sub-scanning direction is divided into four, the sub-line ( Four types of strobe signals (1/4), (2/4), (3/4), and (4/4) are output.

  The basic timing generation unit 63 generates a corresponding timing signal when the sub-scanning direction is divided into n according to the gradation information set by the CPU I / F unit 64, and outputs the timing signal to each unit. The CPU I / F unit 64 outputs the above gradation information, and performs address decoding processing, registration processing of each module, and the like.

  On the other hand, the motor clock generation unit 61 includes a frequency division ratio setting register 61a and a counter unit 61b. The CPU I / F unit 64 sets the frequency division ratio in the frequency division ratio setting register 61a, and the motor controller unit starts from the counter unit 61b. A kit motor drive signal is output to 46.

  The motor controller unit 46 includes a CPU I / F unit 70, various clock generation units 71, a kit motor control circuit 72, a belt motor control circuit 73, a fixing motor control circuit 74, and a paper feed motor control circuit 75. The kit motor control circuit 72 is provided with a phase setting register 72a and a current control circuit 72b, and drive signals are output to the corresponding kit motors 34Y, 34M, 34C, and 34K via the drivers 77Y to 77K. The kit motor control circuit 72 is supplied with the kit motor drive signal from the engine controller 45 as described above.

  The various clock signal generation unit 71 includes a throughput setting register 71a, and outputs various clock signals according to throughput information described later set in the throughput setting register 71a by the CPU I / F unit 70.

  This clock signal is supplied to the belt motor control circuit 73, the fixing motor control circuit 74, and the paper feed motor control circuit 75. The belt motor control circuit 73 outputs a motor drive signal in accordance with the clock signal and drives the belt motor 80 via the driver 79. The fixing motor control circuit 74 outputs a motor driving signal according to the clock signal and drives the fixing motor 82 via the driver 81. Further, the paper feed motor control circuit 75 also outputs a motor drive signal according to the clock signal, and drives the paper feed motor 84 via the driver 83.

  The current control circuit 72b of the kit motor control circuit 72 supplies drive current to the corresponding kit motors 34Y, 34M, 34C, and 34K via the drivers 77M to 77K, and controls the current value of the drive current. The motor torque generated in the kit motors 34Y, 34M, 34C, 34K is controlled.

  Similarly, the current control circuit 73a of the belt motor control circuit 73 also supplies a drive current to the corresponding belt motor 80 via the driver 79, and generates the belt motor 80 by controlling the current value of this drive current. Control motor torque.

In the above configuration, the processing operation of this example will be described below.
Note that the processing operation of the printing apparatus 1 of this example is to detect generation sources such as resonance vibrations caused by kit motors 34Y, 34M, 34C, 34K, gears, etc. when the printing apparatus 1 is driven, and to reduce vibrations. Therefore, the quality of the print image is improved. Therefore, first, the generation source of the resonance vibration caused by the kit motors 34Y, 34M, 34C, 34K and the gears is detected. For this reason, in this example, the patch is transferred onto the transfer belt 14 and a patch pattern is generated on the transfer belt 14.

  For this reason, the patch data is first read from the ROM 37 and transmitted to the dot pattern generation unit 65 of the head I / F control unit 60 via the video I / F control unit 40. The dot pattern generation unit 65 generates a patch pattern based on the patch data supplied from the video I / F control unit 40 and transmits the patch pattern to the print head 10 via the head data transmission unit 66.

  The print head 10 exposes the photosensitive drum 7 corresponding to the input patch pattern, forms an electrostatic latent image corresponding to the patch pattern on the photosensitive surface of the photosensitive drum 7, and develops the electrostatic latent image on the developing roll. 12, and the patch pattern is transferred onto the transfer belt 14.

  FIG. 5 is a view showing a state in which this patch pattern is transferred to the transfer belt 14. As shown in the figure, eight patch patterns P1, P2, P3,... P8 are transferred in the moving direction of the transfer belt 14, and moved in the belt moving direction of the transfer belt 14. The density sensor 35 a detects the moving patch pattern and transmits detection data to the CPU I / F unit 64 via the sensor driving circuit 62.

  For example, FIG. 6 shows an example of a patch pattern detected when the patch train passes near the sensor, and the patch patterns P1, P2, P3,... Shown in FIG. The patch patterns P1 ′, P2 ′, P3 ′,. Specifically, the sensor detection signal 1 shown in the figure is a signal waveform when the density sensor 35a detects the patch pattern of the patch P1, for example, and the sensor detection signal 2 is a patch of the patch P1 ′ that is the density sensor 35a. It is a signal waveform when a pattern is detected. The CPU I / F unit 64 detects the occurrence of jitter at a cycle of 24 dots by Fourier transform described later.

  FIG. 7 shows another example, in which a so-called character dropout phenomenon occurs. The sensor detection signal 3 shown in the figure is a signal waveform when the density sensor 35a detects patch patterns P1, P2, P3,..., And is a patch pattern for normal printing. On the other hand, the sensor detection signal 4 is an example of a signal waveform when the density sensor 35a detects a patch array P1 ″, P2 ″, P3 ″,... A short pulse is generated. Although two pulses are generated in each patch in the figure, the number of pulses generated in each patch is not limited to two.

  For example, when the sensor detection signal 4 is the above signal, the CPU I / F unit 64 generates a character dropout phenomenon when compared with a patch pattern for detecting a dropout phenomenon stored in a table (not shown). Judge that. In addition, the character dropout phenomenon is, for example, an image defect in which a portion in the character is whitened, and is a phenomenon in which the print density becomes lighter from the outline portion of the character toward the inside. In the development or transfer process, This is a phenomenon that occurs when a failure occurs in drive matching with the photosensitive drum 7, and the cause is considered to be caused by the movement of the kit motors 34Y, 34M, 34C, 34K and the gears described above.

  Next, FIG. 8 shows an analysis result obtained by Fourier transforming the data detected by the concentration sensor 35a. The analysis results shown in FIG. 9 are based on the conditions shown in FIG. 9. For example, the analysis results are based on the conditions where the linear speed is 142 mm / s, the printing speed is 32 PPM / A4, and the paper interval is 56 mm.

  In the example shown in the figure, jitter occurs in the 24 dots shown in FIG. 6 described above, and this jitter exceeds the set image determination threshold, which causes deterioration in image quality. In this example, the jitter is reduced by the following processing.

First, the relationship between the dot period of the jitter exceeding the image determination threshold and the frequency (Fj) is calculated by the following calculation formula.
Fj = 1 / ((25.4 / RL × Pj) / SS)

  Note that RL indicates resolution, Pj indicates a band period (detected dot period), and SS indicates the above-described linear velocity. Therefore, for example, if the resolution (RL) is 600 DPI and the linear velocity (SS) is 142 mm / s, the detected dot period (Pj) is 24 dots, and the frequency (Fj) is based on the above formula. 140Hz.

  FIG. 10 is a diagram showing the relationship between the detection result by the density sensor 35a and the jitter period obtained by the above calculation formula. The example in which the dot period (Pj) is 24 dots is No. 1 shown in the figure. Similarly, jitter exceeding the image determination threshold is generated in the 19-dot period based on the detection result by the density sensor 35a. In this case, as shown in No. 2, the jitter period is calculated as 176 Hz. Further, when jitter exceeding the image determination threshold is generated in a 5-dot period, the jitter period is calculated as 670 Hz as shown in No. 3.

  Further, as a result of detection by the density sensor 35a, the 24 dot cycle shown in No. 1 indicates that 1.0 mm cycle jitter is generated, and the 19 dot cycle shown in No. 2 shows 0.8 mm cycle jitter. The 5-dot period shown in No. 3 indicates that a jitter with a period of 0.2 mm is generated.

  Next, FIG. 11 shows a specific configuration of the drum unit including the developing device 11 described above. As described above, the cleaner 8, the charging roller 9, the print head 10, and the developing device are provided in the vicinity of the peripheral surface of the photosensitive drum 7. 11 is disposed inside the developing device 11, a toner stirring member 11a, a toner supply roller 11b for supplying toner to the developing roller 12, and a doctor blade 11c for regulating the toner layer on the developing roller 12 to a constant layer thickness. It is installed.

  The kit motor pinion gear 85 attached to the rotation shaft of the kit motor 34 (34Y, 34M, 34C, 34K) transmits the rotational force of the corresponding kit motor 34 to the drum gear 87 through the intermediate gear 86. Therefore, the rotational force from the corresponding kit motor 34 is transmitted to the above-described photosensitive drum 7 through the kit motor pinion gear 85, the intermediate gear 86, and the drum gear 87.

  Here, the number of teeth of the kit motor pinion gear 85 and the drum gear 87 and the feed amount per tooth are as shown in FIG. From the configuration shown in the figure, the feed amount per tooth of the kit motor pinion gear 85 is 1.0 mm, which is the same as the 1.0 mm cycle jitter shown in No. 1 described above. Therefore, when the feed amount per tooth of the kit motor pinion gear 85 is a numerical value shown in FIG. 12, it is considered that the kit motor pinion gear 85 is a cause of the occurrence of jitter. That is, the feed amount per tooth of the kit motor pinion gear 85 is 1.0 mm shown in FIG. 12, which matches the jitter cycle shown in No. 1 described above.

  Further, the 19-dot period shown in No. 2 indicates that a jitter with a period of 0.8 mm is generated, and the drum gear 87 is considered to be the cause of the occurrence of jitter in the same manner as described above. That is, the feed amount per one tooth of the drum gear 87 is 0.8 mm as shown in FIG. 12, which matches the jitter cycle shown in No. 2 described above.

  On the other hand, the example shown in FIG. 13 is an example of a belt drive mechanism including the transfer belt 14 described above. As described above, the transfer belt 14 is driven by the drive roller 15, and the drive roller 15 includes the belt gear 88, the intermediate gear 89, The rotational force of the belt motor 90 is transmitted through a motor pinion gear 91 attached to the belt motor 90.

  Here, the number of teeth of the belt gear 88 and the feed amount per tooth are as shown in FIG. Therefore, the 5-dot period shown in No. 3 described above indicates that a jitter with a period of 0.2 mm is generated, and the belt gear 88 is considered to be the cause of the occurrence of jitter in the same manner as described above. That is, the feed amount per one tooth of the belt gear 88 is 0.2 mm as shown in FIG. 14, which matches the jitter cycle shown in No. 3 described above.

  The above example is an example of the jitter caused by the gear, but the jitter generated by the resonance phenomenon of the kit motors 34Y, 34M, 34C, 34K can be detected in the same manner. FIG. 15 shows the output timing of the clock signal when driving the kit motors 34Y, 34M, 34C, and 34K with four colors and two phases using a reference clock of 0.2f (for example, f is 1000 Hz). In this case, the kit motors 34Y and 34C are driven with the same phase, and the kit motors 34M and 34K are driven with the same phase. In this case, as shown in FIG. 16, the resonance vibration caused by the driving of the stepping motor is generated, and actually becomes a composite wave of the resonance vibration shown in FIG. In this case, as shown in FIG. 18, jitter occurs at a frequency of 0.25f.

  Even when the kit motor is driven with the four colors and one phase described in the background art, as described above, the resonance vibration (see FIG. 31) resulting from the driving of each stepping motor is generated, and the combined wave ( From the Fourier analysis based on FIG. 32, for example, jitter occurs at a specific frequency of 0.5f (see FIG. 33).

Next, a processing method when the above jitter occurs will be described.
FIG. 19 shows a processing method in each of the above cases. First, when it is caused by the resonance phenomenon of the kit motors 34Y, 34M, 34C, and 34K, it is detected that the jitter is caused by the kit motors 34Y, 34M, 34C, and 34K based on the patch pattern described above, and phase control is performed. Do. Specifically, the kit motors 34Y, 34M, 34C, and 34K that have been driven with four colors and one phase or four colors and two phases are driven with four colors and four phases. This control is performed based on the phase setting information set in the phase setting register 72a by the CPU I / F unit 70 described above, and the kit motor control circuit 72 performs 4 based on the phase setting information set in the phase setting register 72a. The kit motors 34Y, 34M, 34C, and 34K are driven with the four colors.

  FIG. 20 shows the output timing of the clock signal when the kit motors 34Y, 34M, 34C, and 34K are driven with four colors and four phases using a 0.2f reference clock. In this case, each of the kit motors 34Y, 34M, 34C, 34K is driven with a phase difference of 90 degrees. As shown in FIG. 21, even if the resonance vibration caused by the driving of the stepping motor occurs, Is a composite wave of resonance vibration shown in FIG. In this case, FIG. 23 shows the analysis result by Fourier transform, but almost no jitter occurs in the synthesized wave.

  The above example is an example in which the kit motors 34Y, 34M, 34C, and 34K that are driven by four colors and one phase or four colors and two phases are driven by four colors and four phases. A specific method of the phase switching will be described. FIG. 24 is a time chart for explaining this method, and FIG. 25 is a flowchart thereof. This process is executed, for example, in the calibration process of the printing apparatus 1.

  First, as shown in FIG. 24a, in order to stop the driving of the kit motors 34Y, 34M, 34C, and 34K that are constantly rotating, the rotational speeds of the kit motors are gradually slowed down (b shown in FIG. 24). ) And stop (c shown in FIG. 24).

  Next, the patch data is read from the ROM 37 as described above, transmitted to the dot pattern generation unit 65 of the head I / F control unit 60, a patch pattern is generated, transmitted to the print head 10, and patch printing by the print head 10 is performed. (Step (hereinafter referred to as S) 1). That is, the photosensitive drum 7 is exposed in accordance with the patch pattern, an electrostatic latent image is formed on the photosensitive surface of the photosensitive drum 7, and the electrostatic latent image is developed by the developing roll 12, and is transferred onto the transfer belt 14. The patch is printed on.

  Next, image determination is performed (S2). That is, the patch pattern printed on the transfer belt 14 is read by the density sensor 35a, detection data is transmitted to the CPU I / F unit 64, and image determination is performed. As shown in FIG. 6 described above, the CPU I / F unit 64 detects the occurrence of jitter by Fourier transform when the patch patterns P1 ', P2', P3 ',... Are abnormal. In this case, the countermeasure is taken according to the countermeasure shown in FIG.

  In this example, an example of performing phase control will be described, and phase control is performed by switching clocks (S3). Specifically, as shown in FIG. 24, clock switching processing is performed at the timing (c shown in FIG. 24) when the kit motors 34Y, 34M, 34C, and 34K stop driving. In the example shown in the figure, the phases of clock A (CLKA) and clock B (CLKB) are changed.

  That is, the phases of the clock A and the clock B, which are in the same phase in the steady rotation (a shown in FIG. 24) and the slow-down process (b shown in FIG. 24), are set to 180, for example, when driving of each kit motor is stopped. The phase is converted, and the clock A and the clock B that are phase-converted from the time of slow-up are output (d shown in FIG. 24).

  Specifically, while the driving of the kit motors 34Y, 34M, 34C, and 34K is stopped, the data of the phase setting register 72a is changed, and a phase-converted clock is applied from the time of slow-up. Perform conversion. In the above example, when steady rotation is reached (e shown in FIG. 24), the phases of the clock A and the clock B are converted by 180 degrees, but the phases of the clock A and the clock B are converted by 90 degrees. Alternatively, it may be configured to convert 270 degrees. That is, in the calibration process or the like, while the driving of the kit motors 34Y, 34M, 34C, and 34K is stopped, the data of the phase setting register 72a is changed and the phases of the clock A and the clock B are converted. Can be done.

  By processing in this way, it is possible to prevent the occurrence of jitter. Accordingly, by starting the printing process thereafter (S4), it is possible to perform print output with excellent print quality. In the above example, two clocks, clock A and clock B, have been described. However, the phases of the kit motors 34Y, 34M, 34C, and 34K that are driven by one of four colors and one phase are four colors and four phases. In the case of conversion to drive, for example, four clocks A to D are used, and while the drive of the kit motors 34Y, 34M, 34C, 34K is stopped, the phase setting register 72a described above is stopped. Of course, the data is changed and the phase conversion is performed.

  26 and 27 perform the above phase conversion while each motor is being driven. Jitter generation is determined without stopping the driving of the kit motors 34Y, 34M, 34C, and 34K, and measures against the jitter are taken. Is what you do.

  FIG. 26 is a time chart for explaining this method, and FIG. 24 is a flowchart of the method, in which phase conversion is performed between so-called sheets, in which printing is not performed on sheets. That is, the clocks A and B having the same phase are output, the kit motors 34Y, 34M, 34C, and 34K are rotated regularly (a shown in FIG. 26), and patched on the transfer belt 14 between the sheets (b shown in FIG. 26). Printing is performed (step (hereinafter referred to as ST) 1).

  Next, as described above, image determination is performed (ST2), and when the occurrence of jitter is detected, phase control is performed by switching the clock (ST3). In this phase control method, as shown in FIG. 26, clock switching processing is performed at the timing between sheets (b shown in FIG. 26), and for example, the phases of clock A and clock B are converted by 180 degrees.

  Also in this example, the phase of clock A and clock B is converted by 180 degrees during steady rotation after clock switching (c shown in FIG. 26), but the phase of clock A and clock B is converted by 90 degrees. You may comprise so that it may convert 270 degree | times. That is, for example, the data in the phase setting register 72a may be changed between the sheets to perform processing for converting the phases of the clock A and the clock B.

  By processing in this way, it is possible to prevent the occurrence of jitter without stopping the driving of the motor. Accordingly, by starting the printing process thereafter (ST4), it is possible to perform print output with excellent print quality. In this example, the two clocks, clock A and clock B, have been described, but the phases of the kit motors 34Y, 34M, 34C, and 34K that are driven with four colors and one phase or four colors and two phases are four colors and four phases. In the case of conversion to drive, for example, four clocks A to D are used, for example, and the data in the phase setting register 72a is changed between the papers to perform phase conversion.

  Next, a case where jitter is caused by gears will be described. As described above, if it is found that the cause of jitter is caused by the gear based on the patch pattern, as shown in FIG. 19, the current value is controlled, the torque generated in the gear is changed, and jitter vibration is eliminated. To do. For example, a control signal is sent from the CPU I / F unit 70 to the current control circuit 73a of the belt motor control circuit 73, the current value supplied to the belt motor 80 is changed, and the torque of the belt gear 88 is adjusted. Further, a control signal is sent from the CPU I / F unit 70 to the current control circuit 72b of the kit motor control circuit 72 to change the current value supplied to the kit motors 34Y, 34M, 34C, 34K, and the kit motor pinion gear 85 and drum gear 87. Adjust the torque.

  On the other hand, when the above-described void phenomenon occurs, the speed control shown in FIG. 19 is performed to eliminate the character void phenomenon. For example, a signal for changing the linear velocity is output from the throughput setting register 71a of the various clock generators 71 to the belt motor control circuit 73, and the rotational speed of the belt motor 80 is adjusted to eliminate the character dropout phenomenon.

FIG. 28 is a diagram for reference when examining the cause of the occurrence of jitter based on the jitter period detected by the density sensor 35a, and is obtained by the following calculation formula.
Z = f / fn (where Z represents the frequency ratio, f represents the excitation force drive frequency, and fn represents the natural drive frequency)

  In the figure, peak a indicates harmonic resonance, peak b indicates harmonic resonance, and peak c indicates fractional harmonic resonance. The harmonic resonance is a vibration that occurs when the natural driving frequency fn and the excitation force driving frequency f coincide with each other, and is a case where the frequency ratio (Z) = 1/1. For example, this is vibration that occurs when the feed amount per tooth of the kit motor pinion gear 85 is 1.0 mm cycle and the jitter cycle is 1.0 mm. Further, this is a vibration that occurs when the feed amount per tooth of the drum gear 87 is a period of 0.8 mm and is the same as a jitter period of 0.8 mm.

  On the other hand, the harmonic resonance is a vibration that occurs when the frequency ratio Z of the excitation force drive frequency f to the natural drive frequency fn is 1 / n (n is a natural number), and the fractional harmonic resonance is an excitation force drive for the natural drive frequency fn. This vibration is generated when the frequency ratio Z of the frequency f is N (N is a natural number).

  Therefore, in the description of the above embodiment, the example of harmonic resonance has been described. However, the occurrence of jitter based on harmonic resonance or fractional harmonic resonance can be similarly known from the detection result of the patch pattern.

  FIG. 29 is a time chart showing a specific driving example of the drivers 77M to 77K. The drivers 77M to 77K perform the same drive, respectively, and generate the signals of the voltages A and B shown in the figure based on the phase difference signals of PH1 and PH2, and the currents A and B in the figure. It outputs to the corresponding kit motors 34Y, 34M, 34C, 34K at the timing shown. Further, the kit motors 34Y, 34M, 34C, and 34K are driven by 1 and 8 degrees by one pulse shown in FIG. The driving of the drivers 77M to 77K is not limited to the above configuration.

  As described above, according to the printing apparatus of this embodiment, it is possible to reduce the occurrence of jitter due to the motor resonance phenomenon by performing phase control of the kit motors 34Y, 34M, 34C, and 34K.

  Also, by controlling the current control of the kit motors 34Y, 34M, 34C, 34K and the current supplied to the belt drive motor 80 of the transfer belt 14, the torque of the rotating body such as gears is adjusted to reduce the occurrence of jitter. can do.

  Furthermore, when a dropout phenomenon occurs, it is possible to eliminate the dropout phenomenon by changing the linear velocity and adjusting the throughput.

  Although several embodiments of the present invention have been described, the present invention is included in the inventions described in the claims and their equivalents. Hereinafter, the invention described in the scope of claims at the beginning of the filing of the present patent application will be added.

Appendix 1
A motor for driving a rotation mechanism having a gear;
Phase setting means for setting a phase when driving the motor;
Current control means for controlling the current supplied to the motor;
Detecting means for detecting jitter caused by driving of the motor or rotation of the gear;
Control means for setting a phase of the motor by the phase setting means based on a detection result by the detection means, and for controlling a current supplied to the motor by the current control means;
A printing apparatus comprising:

Appendix 2
The detection means for detecting the jitter stops driving the motor during calibration of the apparatus, changes the phase information set in the phase setting means, and drives the motor based on the changed phase information. The printing apparatus according to appendix 1, wherein the printing apparatus is restarted.

Appendix 3
The detection means for detecting the jitter changes the phase information set in the phase setting means when the paper is not printed, and restarts the driving of the motor based on the changed phase information. The printing apparatus according to appendix 1, characterized by:

Appendix 4
The control means further controls the speed of the motor to adjust the throughput of the apparatus when a hollow image is generated due to the driving of the motor or the rotation of the gear, and the throughput of the apparatus is adjusted. Printing device.

Appendix 5
Supplementary note 1 or 2, wherein the motor is arranged for each of a plurality of colors, and the phase setting by the control means varies the phase of the motor driven for each color. A printing apparatus according to 1.

Appendix 6
Stop driving the motor provided for each of a plurality of colors, change the phase information set in the phase setting means for each motor, and restart the driving of the motor based on the changed phase information The printing apparatus according to appendix 2 or 3, wherein:

Appendix 7
The detecting means for detecting the jitter is a sensor for detecting a patch pattern transferred to a transfer belt for holding image information while an image based on print data is transferred to a recording medium. The printing apparatus according to 2, 3, 4, 5, or 6.

Appendix 8
The printing apparatus according to appendix 7, wherein the transfer belt to which the patch pattern is transferred is driven by the motor.

Appendix 9
The printing apparatus according to claim 1, wherein the jitter caused by the rotation of the gear is adjusted by controlling a current supplied to the motor by the current control unit.

DESCRIPTION OF SYMBOLS 1 ... Printing apparatus 2 ... Image formation part 3 ... Intermediate transfer belt unit 4 ... Paper feed part 5 ... Conveyance unit 6 for double-sided printing (6Y, 6M, 6C, 6K) ... Image Forming unit 7 ... photosensitive drum 8 ... cleaner 9 ... charging roller 10 ... printing head 11 ... developing device 12 ... developing roller 13a ... I / F controller 13b ... engine control unit 14 Transfer belt 15. Drive roller 16. Driven roller 17. Belt position control mechanism 18. Primary transfer roller 19. Belt cleaner unit 20. Waste toner collection containers 21 a, 21 b and 21 c. ..Paper take-out roller 23..standby conveying roller pair 24..secondary transfer roller 25..belt fixing device 26..conveying roller pair 27..discharge tray 28..discharge roller pair 30..start Transmission path 31 ..Intermediate return path 32 ..Terminal return path 33 ..Standing conveyance roller pair 34Y, 34M, 34C, 34K ..Kit motor 35a ..Concentration sensor 35b ..Theta (.theta.) Sensor 36..Reception control Part 37 ROM
38. Font ROM
39..Display control unit 40..Video I / F control unit 41..Memory 41a..Standard RAM
41b .. Expansion RAM
42 .. Compression / decompression control unit 43.. MPU
45..Engine controller 46..Motor controller 47..MPU
48. Fixing control unit 49. High voltage control unit 56 High voltage unit 60 Head I / F control unit 61 Motor clock generation unit 62 Sensor drive circuit 63 Basic timing generation unit 64 CPUI / F unit 65..dot pattern generation unit 65a..line buffer 66..head data transmission unit 67..head control signal generation unit 68..strobe signal generation unit 70..CPU I / F unit 71..various clock generation Unit 71a .. throughput setting register 72 .. kit motor control circuit 72a .. phase setting register 72b .. current control circuit 73 .. belt motor control circuit 72a .. current control circuit 74 .. fixing motor control circuit 75. Paper motor control circuits 77M to 77K, 79, 81, 83 ..Driver 80 ..Belt motor 82 ..Fixing motor 84. Motor 85 ... kit motor pinion gear 86, 89 ... intermediate gear 87 .. drum gear 88 .. belt gear 90 ... belt motor 91 ... motor pinion gear

Claims (8)

A process of driving a rotation mechanism having a gear by a motor;
A process of changing the driving phase of the motor when driving the motor;
A process of changing a current value supplied to the motor;
A process of Fourier transforming data when the patch pattern is read by a predetermined reader;
A process of deriving a period value of jitter caused by driving the motor or rotating the gear based on the result obtained by the Fourier transform,
When the derived period value of the jitter is a jitter period value resulting from driving of the motor, the driving phase is changed , and the derived period value of the jitter is a jitter value resulting from rotation of the gear. If the period value, make a change of the current value,
And a printing control method. A process of driving a rotation mechanism having a gear by a motor;
A process of changing the driving phase of the motor when driving the motor;
A process of changing a current value supplied to the motor;
A process of changing the rotational speed of the motor;
A process of Fourier transforming data when the patch pattern is read by a predetermined reader;
A process of deriving a period value of jitter caused by driving the motor or rotating the gear based on the result obtained by the Fourier transform,
When the derived period value of the jitter is a jitter period value resulting from driving of the motor, the driving phase is changed , and the derived period value of the jitter is a jitter value resulting from rotation of the gear. If the period value, to change or modify the rotational speed of the current value,
And a printing control method. A process of driving a rotation mechanism having a gear by a motor;
A process of changing the driving phase of the motor when driving the motor;
A process of changing a current value supplied to the motor;
A process of changing the rotational speed of the motor;
A process of Fourier transforming data when the patch pattern is read by a predetermined reader;
A process of deriving a period value of jitter caused by driving the motor or rotating the gear based on the result obtained by the Fourier transform,
When the derived period value of the jitter is a jitter period value resulting from driving of the motor, the driving phase is changed , and the derived period value of the jitter is a jitter value resulting from rotation of the gear. If the period value, performing said rotational speed changing and modifying the current value,
And a printing control method.   The printing control method according to claim 1, wherein the process of changing the driving phase is performed after driving of the motor is stopped.   4. The printing according to claim 1, wherein the process of changing the driving phase is performed when the image forming unit is not forming an image without stopping the driving of the motor. 5. Control method.   6. The process according to claim 1, wherein the motor is provided for each of a plurality of colors to form an image, and the process of changing the drive phase varies the drive phase for each color. The printing control method as described.   The derived period value of the jitter is determined when the occurrence of jitter is caused by rotation of a gear that transmits the drive of the first motor that drives the image forming unit to the image forming unit, and / or the transfer belt. 7. The print control method according to claim 1, wherein the print control method is detected when the drive of the second motor that drives the belt is caused by rotation of a gear that transmits the transfer belt to the transfer belt. 8. The jitter periodic value derived from the above-described case is that the occurrence of jitter is caused by the rotation of the pinion gear directly connected to the first motor, and the driving of the first motor is performed by the photosensitive of the image forming unit. The value is different between the case where the rotation of the drum gear transmitted to the body drum is caused and the case where the rotation of the gear which transmits the drive of the second motor to the transfer belt is caused. The printing control method according to claim 7 .