JP3729462B2 - Paper transport control device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a paper conveyance control device installed in an image forming apparatus such as a copying machine or a printer, and in particular, shortens the time (hereinafter referred to as FCOT) from when the start button is pressed until the first sheet is output. In addition, the present invention relates to a paper conveyance control device suitable for reducing noise.
[0002]
[Prior art and its problems]
In general, in an image forming apparatus such as a copying machine, the speed at which a sheet is conveyed to a registration roll (hereinafter referred to as a registration roll) is controlled at a single speed equal to the image forming process speed, or the conveyance speed to the registration roll is high. , 2-speed control is performed with the process speed after the registration roll.
However, when the paper is conveyed by the first speed control, the configuration and control of the apparatus are simplified, but there is a drawback that the FCOT becomes long because the time for the paper to reach the registration roll is long. In the case of the 2-speed control, the FCOT can be shortened. However, when all the sheets are conveyed to the registration roll at a high speed, in addition to the noise due to the driving of the apparatus, the noise generated by the meshing of the gear in the driving system of the conveying apparatus. In addition, noise generated by rubbing the paper and the conveyance path increases, and variation in arrival time to the registration roll increases. In addition, when a paper jam or the like occurs on the preceding paper, there is a problem that the subsequent paper is wound up and it takes a lot of work. In addition, there is a problem that the structure of the image forming apparatus becomes more complicated as the number of tray stages is increased in order to realize a plurality of stages of paper conveyance speed control, which requires additional drive systems and separation.
SUMMARY OF THE INVENTION An object of the present invention is to provide a paper transport control device capable of shortening the FCOT and reducing noise.
[0003]
[Means for Solving the Problems]
In order to achieve the above object, the present invention described in claim 1 is directed to a registration for carrying a plurality of paper feeding units and a paper conveyed from each of the paper feeding units in accordance with an image forming timing. A roll, a conveyance roll arranged on a common sheet conveyance path of each sheet feeding unit provided between a plurality of sheet feeding units and a registration roll, and a sheet conveyance from the selected sheet feeding unit In an image forming apparatus including a control unit that drives and controls a conveyance roll, a plurality of paper feeding units are configured to convey the sheet to the registration roll at an increased speed or the same speed as the conveyance speed of the registration roll. Of these, a conveyance line disposed on a common sheet conveyance path of each sheet feeding unit provided between the sheet feeding unit and the registration roll that has the shortest sheet conveyance length from the sheet feeding unit to the transfer unit. The sheet transport length to the transfer unit is the shortest so that the sheet is transported at the same speed until the transport roll of the first drive system is reached at the same speed as the transport speed of the first drive system that drives the motor and the registration roll. And a second drive system that motor-drives a transport roll disposed on a common paper transport path of other paper feed units other than the paper feed unit. When the paper feed unit that minimizes the paper conveyance length to the transfer unit is selected, the paper is conveyed to the transfer unit by switching to the first drive system at a speed that is higher than the conveyance speed of the registration roll. When a paper feed unit other than the paper feed unit with the shortest paper transport length is selected, the first drive system is switched to the first drive system at the same speed as the transport speed on the registration roll. Convey paper by the second drive system The features.
[0006]
[Action]
According to the present invention, the first drive system or the second drive system is switched with respect to the selected sheet feeding unit, and the sheet conveyance speed before registration is determined, so that the movement of the sheet is simplified, and the conveyance system before registration. In this way, the variation in the sheet can be kept small, and the sheet can be conveyed stably.
In addition, when a paper feeding unit having the shortest paper conveyance length from the paper feeding unit to the transfer unit is selected from among a plurality of paper feeding units, the first speed that is increased relative to the conveyance speed of the registration roll is selected. Since the paper is transported by switching to the drive system, the paper is transported by the drive system with few transport rolls, and the paper is transported at the process speed with the maximum noise level of the image forming apparatus even if the paper feed speed is increased. Is equivalent to
[0007]
【Example】
DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a sheet conveying device of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of a copying machine to which an embodiment of a sheet conveyance control apparatus of the present invention is applied.
A platen glass 2 is provided on the upper surface of the apparatus main body 1 of the copying machine. A document is set on the platen glass and exposed and scanned by the exposure optical system 3. As a method of setting an original, when an operator sets an original directly on the platen glass and equipped with an automatic original feeder 1A, the original is placed on the automatic original feeder 1A and automatically fed one by one. And the case where it sets on platen glass is selected suitably.
[0008]
The exposure optical system 3 exposes and scans the document D set on the platen glass, and forms an electrostatic latent image on the surface of the photosensitive drum 4. The electrostatic latent image formed on the photosensitive drum 4 becomes a toner image visualized by the developing device 5. Then, the toner image is transferred to the conveyed paper by the transfer device 6, fixed by the fixing device 7, and discharged to the paper discharge tray 9. In addition, a first tray 9 is provided in the apparatus main body 1, and the paper S in the first tray is conveyed to the photosensitive drum 4 by the first paper conveying device 10.
[0009]
A plurality of, for example, three, second to fourth trays 11 are arranged in the cabinet 20 on which the apparatus main body 1 is placed, and the sheets S accommodated in the respective trays 11a, 11b, and 11c are respectively provided. The paper is conveyed by the paper conveying devices 12a, 12b, and 12c. Reference numeral 13 denotes a paper transport path for performing paper reversal or the like in double-sided copying or the like, and reference numeral 14 denotes a paper transport device for transporting the recording on the paper on which reversal or the like has been operated.
[0010]
The paper transport apparatus 10 includes a pick roll 21 for taking out the paper S in the first tray 9, a roll pair including a paper feed roll 22 and a separation roll 23 for separating the taken paper one by one, and a first pair. The transport roll 24 and the second transport roll 25 are configured. Further, a registration roll 26 is provided between the first conveying roll pair 24 and the photosensitive drum 4, and the rotational driving of the photosensitive drum 4 and the registration roll 26 and the rotational driving of each roll upstream of the registration roll are independent. are doing. The rotation of the photosensitive drum 4 and the registration roll 26 is driven at a constant process speed, and the roll upstream of the registration roll 26 has a first speed equal to the process speed and a second speed faster / slower than the first speed. And can be switched to two stages. This speed switching is performed by changing the number of rotations of a motor as a driving source or switching a clutch provided between driving gear trains. Note that all the rolls may be driven by the same drive source, and the speed of only the roll upstream of the registration roll 26 may be switched by a clutch or the like.
[0011]
FIG. 2 shows a control block of the paper transport system of this embodiment. Signals from the control panel 33 and the registration sensor 35 are input to the CPU 31 via an input interface (I / F) 32. The CPU 31 also includes a counter 36 for calculating the number of sheets set by the number setting key 34, a timer 37 for adjusting the timing of each operation, and a memory 38 for storing each data. The CPU 31 gives a motor control command to the driver 40 via the output interface (I / F) 39, and the driver 40 rotates the motor 41. Similarly, the driver 42 operates the clutch 43 based on the transfer roll speed switching command sent from the CPU, and switches the speed of the transfer roll between high speed and low speed.
[0012]
Next, a specific example of paper conveyance control will be described. FIG. 3 shows an example in which the control is changed between the first sheet and the subsequent sheets. The first sheet fed first to the apparatus main body 1 is fed by the high-speed rotation of the pickup roll 21 and the transport rolls 24 and 25 and is abutted against the registration roll 26 where the rotation is stopped. Etc. are corrected. Thereafter, the registration roll 26 is driven in accordance with the timing of image formation, and the first sheet is fed to the photosensitive drum 4 at a low process speed. The second sheet is fed at the process speed after the time Δt has elapsed since the registration roll 26 started rotating.
[0013]
FIG. 4 shows a processing flow of the paper transport control. Here, paper conveyance by high-speed rotation of the motor is referred to as “high-speed running”, low-speed rotation is associated with the process speed, and paper conveyance at this speed is described as “low-speed running”.
First, the set number is confirmed (S100), and it is determined whether or not the set number is one (S101). In the case of a single sheet, the sheet is set at high speed and conveyed (S102). When the registration sensor (SNR) detects the sheet (S103), the motor (MOT) is temporarily stopped (S104). Thereafter, it is restarted at a low speed in accordance with the image formation timing (S105). When the trailing edge of the sheet is detected by the registration sensor (S112), the motor is stopped (S113).
[0014]
On the other hand, if the set number of sheets is two or more, the sheet is first set to high-speed traveling and conveyed (S106), and when the first sheet is detected by the registration sensor (S107), the motor is temporarily stopped (S108). ). Thereafter, it is restarted at a low speed in accordance with the image formation timing (S109). The number of discharged sheets + 1 = the set number of sheets is determined (S110). If not satisfied, the low speed running is set (S111), and the process returns to step 107 to carry the next sheet. When the last sheet is determined (S110), the trailing edge of the sheet is detected (S112), and the motor is stopped (S113).
[0015]
Here, when the second and subsequent sheets can be sent out when the motor rotates at high speed, the second and subsequent sheets may be sent out at high speed, and the conveyance by high speed running may be performed until the first sheet is switched to low speed. The control flow in this case is realized by changing the portion A in FIG. 4 to the flow shown in FIG. That is, the paper is first set to high-speed running and conveyed (S120), and the number of discharged sheets + 1 = the set number of sheets is determined (S121). Since it is the first sheet, it is determined NO in step 121, and then it is determined whether or not the first sheet has been switched to a low speed (S125). Here, when it is confirmed that the first sheet has been switched to the low speed, the low speed running is set (S111), and the following sheet is conveyed at the low speed. On the other hand, when the first sheet is not switched to the low speed, the high speed running is continuously maintained (S120). When the number of discharged sheets + 1 = the set number of sheets is satisfied (S121), that is, when the last sheet is detected by the registration sensor (S122), the motor is temporarily stopped (S123). Thereafter, it is restarted at a low speed in accordance with the image formation timing (S124). Thereafter, the same processing as in FIG. 4 is executed.
[0016]
FIG. 6 shows another specific example of the sheet conveyance speed of each roll. In this example, as shown in FIG. 7, when the paper transport path is long in the cabinet 20 shown in FIG. 1, when the first paper S1 is being transported at a high speed, the second and subsequent sheets are processed. When the sheet is sent out, the sheet is initially fed at a high speed, and when the first sheet starts to be conveyed by the registration roll 26, the second and subsequent sheets S2, S3 are also lowered. That is, the sheet conveyance control is performed in the single sheet mode and the multiple sheet mode. This process will be described with reference to FIG.
[0017]
First, the set number of sheets is confirmed (S130), and it is determined whether or not the set number is one (S131). In the case of one sheet, the sheet is set to high speed and conveyed (S132). When the registration sensor (SNR) detects the sheet (S133), the motor (MOT) is temporarily stopped (S134). Thereafter, it is restarted at a low speed in accordance with the image formation timing (S135). When the trailing edge of the sheet is detected by the registration sensor (S141), the motor is stopped (S142).
On the other hand, when the set number of sheets is two or more, the sheet is first transported at low speed (S136), and when the first sheet is detected by the registration sensor (S137), the motor is temporarily stopped (S138). ). Thereafter, it is restarted at a low speed in accordance with the image formation timing (S139). The number of discharged sheets + 1 = the set number of sheets is determined (S140), and if not satisfied, the process returns to step 136, and the next sheet is continuously conveyed at a low speed. When the last sheet is determined in step 140 (S140), the trailing edge of the sheet is detected (S141), and the motor is stopped (S142).
According to the above embodiment, the FCOT can be shortened by feeding the first sheet at a high speed, and the productivity can be improved. Further, while the first sheet is being conveyed to the registration roll 26, other parts of the apparatus main body may not be operated, so that the overall noise can be kept low. Furthermore, since the conveyance speed of the second and subsequent sheets is low, noise during continuous copying can be reduced.
[0018]
Next, a description will be given of sheet conveyance control for making the sheet feeding speed from a specific sheet feeding unit faster than the sheet feeding speed of other sheet feeding units. FIG. 9 shows a paper feed drive system in which a first drive system of a specific paper feed unit and a second drive system of another paper feed unit are provided independently. In this embodiment, the sheet feeding speed of the first tray (specific sheet feeding unit) provided in the apparatus main body is made faster than the sheet feeding speed of the second to fourth trays (other sheet feeding units). .
[0019]
The feed motor M1 of the first drive system drives the first paper transport device (FDR) 10, the manual paper transport device (MSI Unit), and the transport roll (T / A Roll) arranged on the paper transport path to the registration gate. To do. Further, the feed motor M2 of the second drive system includes the second to fourth tray paper transport devices (FDR) 12a to 12c, the paper transport device 14 in the duplex mode, and a transport roll (T / A Roll) disposed on the paper transport path. Drive). Here, the sheet conveyance distance from the first tray 9 as a specific paper feed unit to the transfer unit of the process unit is the shortest, but the specific paper feed unit may be any of the second to fourth trays. In this case, the sheet conveyance distance from the specific sheet feeding unit to the transfer unit is not the shortest.
FIG. 10 shows a change in the sheet conveyance speed. Note that speed a <speed b and speed a ≧ process speed. In the case of sending out from the first tray 9, as shown in FIG. 5A, feeding is performed from the tray at a speed “a” or a paper turning speed, and the leading edge of the paper reaches the transport roll (T / A Roll) 1. At this point, the speed is increased and transported at speed b. In the case of sending out from any one of the second to fourth trays 12a to 12c, the transport is performed at a speed a slower than the speed b.
[0020]
FIG. 11 shows a control block of the paper transport system of the above embodiment. The control block of the present embodiment is changed to the control block of FIG. 1 with a function of switching to the first drive system or the second drive system according to tray selection. Here, the fast speed means being fast with respect to the speed of the second drive system, and the slow speed means being slow with respect to the speed of the first drive system. The tray selection key 36 is used to select one of the first tray to the fourth tray shown in FIG. 9, and the first drive system driver 44 and / or the second drive system driver 45 is selected according to the selected tray information. A motor control signal is sent to drive the feed motors M1 and / or M2. For example, when the first tray 9 is a specific paper feeding unit, when the first tray is selected, a fast speed control signal is issued from the CPU 31 to the first drive system driver 44, and the feed motor M1 is moved at a high speed. To drive. As a result, the sheet is sent out from the first tray at a high speed. When the second tray is selected, a slow speed control signal is output from the CPU to the first and second drive system drivers 44 and 45 to drive the feed motors M1 and M2 at a slow speed. As a result, the sheet is sent out from the second tray at a low speed.
[0021]
In this embodiment, the following effects can be expected by adopting a configuration in which the sheet feeding distance is the shortest, that is, the sheet feeding speed from the tray closest to the image forming (process) unit is faster than the other trays.
(1) Since paper conveyance is performed with a small number of drive systems, even if the paper feed speed is increased, the maximum noise level of the image forming apparatus is equivalent to the apparatus that conveys the paper at the process speed.
(2) Since the paper movement is simpler than the control of temporarily stopping the paper and lowering the paper conveyance speed before registering to take the image formation timing, it is possible to suppress the paper variation in the pre-registration conveyance system. The paper gap can be stably conveyed, a stable paper gap can be guaranteed, and the target value of the paper gap can be made smaller than before, which ultimately leads to an improvement in CPM / PPM.
(3) Since only the feeding of the tray closest to the process section is unique, the actual movement of the sheet is unique from the time the sheet is hit by the tray to the front of the process. Therefore, a memory capacity required for setting a jam timer value or the like is smaller than that of other controls.
(4) In the conventional control method, the drive system becomes more complex as the number of tray stages increases. However, in this method, the drive other than the tray closest to the process unit can be combined into one, so that the mechanism can be simplified. .
[0022]
【The invention's effect】
According to the present invention, the first drive system or the second drive system is switched with respect to the selected sheet feeding unit, and the sheet conveyance speed before registration is determined, so that the movement of the sheet is simplified and conveyance before registration is performed. This makes it possible to suppress variations in the paper in the system and to stably carry the paper.
In addition, when a paper feeding unit having the shortest paper conveyance length from the paper feeding unit to the transfer unit is selected from among a plurality of paper feeding units, the first speed that is increased relative to the conveyance speed of the registration roll is selected. Since the paper is transported by switching to the drive system, the paper is transported by a drive system with few transport rolls, and the paper is transported at the maximum noise level of the image forming apparatus at the process speed even when the paper feed speed is increased. Is equivalent to
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating a configuration of an example of an image forming apparatus to which an embodiment of a paper conveyance control device of the invention is applied.
FIG. 2 is a block diagram of a paper transport control unit according to an embodiment of the present invention.
FIG. 3 is a diagram showing changes in the conveyance speed of the first and second sheets according to the present embodiment.
FIG. 4 is a flowchart for changing paper conveyance control for the first sheet and thereafter.
FIG. 5 is a flowchart for performing paper conveyance control with the portion A of FIG. 4 changed.
FIG. 6 is a diagram illustrating a change in the conveyance speed of sheets from the first sheet to the fourth sheet according to another embodiment.
7 is an explanatory diagram of a paper conveyance path that can realize the conveyance speed illustrated in FIG. 6;
FIG. 8 is a flowchart for changing sheet conveyance control between a single sheet mode and a multiple sheet mode.
FIG. 9 is a schematic diagram of a paper feed drive system in which a first drive system of a specific paper feed unit and a second drive system of another paper feed unit are provided independently.
10A and 10B show changes in paper conveyance speed, where FIG. 10A shows a relationship between a specific paper feeding unit and FIG. 10B shows a relationship between the paper conveyance speed of each of the other paper feeding units and the paper leading edge position.
FIG. 11 is a block diagram of a paper feed drive system in which a first drive system of a specific paper feed unit and a second drive system of another paper feed unit are provided independently.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Apparatus main body, 1A ... Automatic document feeder, 2 ... Platen glass, 3 ... Exposure optical system, 4 ... Photosensitive drum, 5 ... Developing device, 6 ... Fixing device, 9 ... Paper tray (specific paper feeding part) , 11 ... Paper tray (other paper feed unit) 10, 12, 14 ... Paper transport device, 20 ... Cabinet, 26 ... Registration sensor, S ... Paper

Claims (1)

Provided between a plurality of sheet feeding units, a registration roll for conveying the sheet conveyed from each sheet feeding unit in accordance with the image formation timing, and between the plurality of sheet feeding units and the registration roll An image forming apparatus comprising: a transport roll disposed on a common paper transport path of each of the paper feed units, and a control unit that drives and controls the transport roll that transports the paper from the selected paper feed unit In
The sheet conveyance length from the sheet feeding unit to the transfer unit among the plurality of sheet feeding units is set so that the sheet is conveyed to the registration roll at an increased speed or the same speed as the conveyance speed of the registration roll. A first drive system that motor-drives a transport roll disposed on a common paper transport path of each of the paper feed units provided between the shortest paper feed unit and the registration roll ;
Other than the paper feeding unit that minimizes the paper conveyance length to the transfer unit so as to convey the paper until it reaches the conveyance roller of the first drive system at the same speed as the conveyance speed of the registration roll A second drive system that motor-drives a transport roll disposed on a common paper transport path of the paper feed unit ,
The control unit increases the speed relative to the conveyance speed of the registration roll when a paper feeding unit having the shortest paper conveyance length from the paper feeding unit to the transfer unit is selected from the plurality of paper feeding units. The paper is transported by switching to the first drive system at the speed, and transported by the registration roll when a paper feed unit other than the paper feed unit having the shortest paper transport length to the transfer unit is selected. An image forming apparatus , wherein the first drive system is switched to the same speed as the speed and the sheet is conveyed by the first drive system and the second drive system .

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