JPH07157149A - Paper conveyance control device - Google Patents

Abstract

PURPOSE:To reduce the noise during paper conveyance in continuous recording without slowing FCOT of a paper conveyor. CONSTITUTION:This paper conveyance control device is equipped with a drive control means which increases the rotational speed of a conveyance roller, for conveying paper sheets to a register roller for taking image forming timing, for the first paper sheet and decreases it for the second sheet and thereafter. In the process of control means, it makes the speed high in the case of one paper sheet (S102) and a motor is temporally stopped (S104) when the paper sheet is detected (S103). Thereafter, it starts again at a low speed matching the image forming timing (S105). On the other hand, when there are two or more paper sheets it starts at a high speed (S106) and the motor temporally stops (S108) when the first paper sheet is detected (S107). Similarly, it starts again at a low speed (S109). A preset number of sheets are conveyed at a low speed (S111). When the rear end of a paper sheet in one sheet mode or the rear end of the last paper in a plurality of sheets mode is detected (S112), the motor stops (S113). Thus noise during continuous recording can be reduced without slowing FCOT.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveyance control device installed in an image forming apparatus such as a copying machine or a printer,
In particular, the present invention relates to a sheet conveyance control device suitable for shortening the time from pressing the start button until the first sheet is output (hereinafter referred to as FCOT) and reducing noise.

[0002]

2. Description of the Related Art Generally, 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 by a first speed equal to the image forming process speed, or Two-speed control is performed in which the conveyance speed up to the registration roll is high and the process speed after the registration roll is the process speed. However, 1
When the sheet is conveyed by the speed control, the configuration and control of the apparatus are simplified, but there is a drawback that FCOT becomes long because the sheet takes a long time to reach the registration roll. In the case of the second speed control, FCOT can be shortened, but when all the sheets are conveyed to the registration rolls at high speed, noise generated by the gear driving in the conveying device in addition to the noise caused by driving the device The noise generated by rubbing the paper and the conveyance path with each other becomes large, and the variation in the arrival time to the registration roll becomes large. In addition, when a paper jam occurs on the preceding paper, the following paper is also thrown in, and it takes a lot of time to deal with the problem.
Further, in order to establish the multi-stage paper transport speed control, as the number of tray stages is increased, it is necessary to add a drive system or separate the drive system, which complicates the structure of the image forming apparatus. An object of the present invention is to provide a sheet conveyance control device capable of reducing FCOT and reducing noise.

[0003]

In order to achieve the above object, the present invention according to claim 1 is directed to a registration roll for carrying a sheet in accordance with an image forming timing, and to the registration roll. In a sheet conveyance control device including a conveyance roll that conveys a sheet and a drive control unit that drives and controls each of the rolls, the drive control unit has a conveyance speed of a registration roll,
A first drive unit that conveys at the same speed, a second drive unit that conveys at a speed higher than the conveyance speed of the registration roll, and the first or second drive depending on the sheet. And a control means for performing switching control of the means, wherein the control means is a second drive means when the first sheet of paper is used and switches to the first drive means after the second sheet. .

Another aspect of the present invention is the invention according to claim 1, which is characterized by a control means having any one of the following configurations. That is, (1) control is performed to start conveyance of the second and subsequent sheets after the first sheet reaches the registration roll. (2) The second sheet transport control unit controls the second sheet transport control unit to transport the second and subsequent sheets at a high speed until the first sheet is switched to the transport speed by the registration roll. (3) In the single-sheet mode, the second drive unit conveys the sheet at a high speed, and in the plural-sheet mode, the first drive unit conveys all the sheets at the same speed as the sheet is conveyed by the registration rolls. It is configured to control the transportation.

According to a fifth aspect of the present invention, in an image forming apparatus having a plurality of paper feed units, first drive means or first drive means for feeding paper from the paper feed units at a first speed.
A third drive means capable of switching between a speed and a second speed, a second drive means for feeding a sheet at a second speed higher than the first speed, and a control means for switching the drive means according to a sheet feeding section. It has a configuration with. According to a sixth aspect of the invention, in the invention according to the fifth aspect, the sheet feeding unit that feeds the sheet by the second driving unit or the third driving unit has at least a sheet from the sheet feeding unit to the transfer unit. It is provided with a paper feed unit that minimizes the transport length. Further claim 7
According to the invention described in claim 6, in the invention according to claim 6, the second driving means or the third driving means for sending out the sheet of the sheet feeding section having the shortest sheet conveyance length from the sheet feeding section to the transfer section. The means is provided independently of the driving means of the other sheet feeding section.

[0006]

According to the present invention, the control means conveys the sheet to the registration roll at a high speed by the second drive means only when recording the first sheet, and thereby the FC
The OT can be shortened. At this time, since each drive unit of the apparatus main body is stopped, even if the paper is conveyed at a high speed and noise is generated, the entire noise does not increase. For the second and subsequent sheets, the first drive means is switched to convey the sheet at a speed equal to the conveying speed of the registration roll. Therefore, since FCOT is determined by the process speed of the first sheet, the time does not become long. Preferably, according to the configuration in which the control of starting the conveyance of the second and subsequent sheets is performed after the first sheet reaches the registration roll, if the conveyance path to the sheet registration roll is long, 1
Even if the first sheet is conveyed at a high speed until it is switched to the low-speed conveyance by the registration roll, it does not catch up with the first sheet, and smooth sheet feeding is possible. Also, until the first sheet is switched to the transport speed by the registration roll,
According to the configuration in which the control is performed to convey the second and subsequent sheets at a high speed, the FCOT can be reliably shortened by increasing the sheet conveyance speed up to the registration roll when the number of sheets is one. . Further, according to the configuration of claim 5, the sheet feeding speed before the registration is determined by the selected sheet feeding unit, so that the movement of the sheet is simplified, and the variation in the sheet in the pre-registration conveying system can be suppressed. Yes, stable paper transportation is possible. According to the configuration of claim 6,
Since the paper is conveyed at a high feed speed with a small number of drive systems, even if the paper feed speed is increased, the maximum noise level of the image forming apparatus becomes equal to or lower than that of an apparatus that conveys the paper at the process speed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the paper conveying apparatus of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a copying machine to which an embodiment of a sheet conveyance control device of the present invention is applied. A platen glass 2 is provided on the upper surface of the main body 1 of the copying machine. A document is set on the platen glass and an exposure optical system 3 performs exposure scanning. As a method for setting the originals, an operator sets the originals directly on the platen glass and an automatic original feeder 1A is provided, and the originals are placed on the automatic original feeder 1A and automatically fed one by one. Then, the case of setting on the platen glass is appropriately selected.

The exposure optical system 3 exposes and scans the document D set on the platen glass to form an electrostatic latent image on the surface of the photosensitive drum 4. Then, 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 onto the conveyed paper by the transfer device 6
And is fixed by the fixing device 7 and discharged to the paper discharge tray 9. In addition, the first tray 9 is provided in the apparatus main body 1.
The sheet S in the first tray is conveyed to the photosensitive drum 4 by the first sheet conveying device 10.

A plurality of stages, for example, three stages of second to fourth trays 11 are arranged in a cabinet 20 in which the apparatus main body 1 is placed, and each tray 11a, 11b, 11c.
The sheets S accommodated in each of the sheet conveying devices 12
It is conveyed by a, 12b, and 12c. Note that reference numeral 13
Is a paper conveyance path for performing paper reversal or the like in double-sided copying and the like, and numeral 14 is a paper conveyance device for conveying the paper for which the reversal or the like has been operated for recording.

The sheet conveying device 10 has a roll pair consisting of a pickup roll 21 for taking out the sheet S in the first tray 9 and a sheet feeding roll 22 and a separating roll 23 for separating the taken out sheets one by one. , The first transport roll 24
And a second transport roll 25. A registration roll 26 is provided between the first pair of transport rolls 24 and the photosensitive drum 4, and the rotational drive of the photosensitive drum 4 and the registration roll 26 and the rotational drive of each roll on the upstream side of the registration roll are independent. is doing. The rotations of the photoconductor drum 4 and the registration roll 26 are driven at a constant process speed, and the rolls on the upstream side of the registration roll 26 have a first speed equal to the process speed and a second speed higher / lower than the first speed.
It is possible to switch between two speeds. This speed switching is performed by changing the rotational speed of a motor as a drive source or switching a clutch provided between drive gear trains.
Alternatively, all the rolls may be driven by the same drive source, and the speed of only the rolls upstream of the registration roll 26 may be switched by a clutch or the like.

FIG. 2 shows a control block of the paper transport system of this embodiment. The CPU 31 has an input interface (I
Signals from the control panel 33 and the registration sensor 35 are input via the / F) 32. Further, the CPU 31 has a counter 36 for calculating the number of sheets set by the sheet number setting key 34 and a timer 3 for adjusting the timing of each operation.
7. A memory 38 for storing each data is provided. CP
The U 31 gives a motor control command to the driver 40 via the output interface (I / F) 39, and the driver 40 rotationally drives the motor 41. Similarly, the driver 42 operates the clutch 43 based on a transfer roll speed switching command sent from the CPU to switch the speed of the transfer roll between high speed and low speed.

Next, a specific example of the sheet conveyance control will be described. FIG. 3 shows an example in which the control is changed for the first sheet and thereafter. The first sheet of paper that is first fed to the apparatus main body 1 is sent out by the high-speed rotation of the pickup roll 21 and the transport rolls 24 and 25, is abutted against the registration roll 26 whose rotation is stopped, and skews the sheet. Etc. are corrected. Thereafter, the registration roll 26 is driven at the timing of image formation, and the first sheet is sent to the photosensitive drum 4 at a low process speed. The second sheet is sent at the process speed after the time Δt has elapsed since the registration roll 26 started rotating.

FIG. 4 shows a processing flow of the paper conveyance control.
Here, the sheet conveyance by the high-speed rotation of the motor is referred to as “high-speed traveling”, the low-speed rotation is associated with the process speed, and the sheet conveyance at this speed is described as “low-speed traveling”. First, the set number is checked (S100), and it is determined whether the set number is one (S101). In case of one,
The sheet is conveyed after being set to high-speed running (S102), and when the registration sensor (SNR) detects the sheet (S103), the motor (MOT) is temporarily stopped (S104). After that, it is restarted at a low speed according to the image forming timing (S10).
5). When the registration sensor detects the trailing edge of the sheet (S112), the motor is stopped (S113).

On the other hand, if the set number of sheets is two or more, the sheet is first set to high-speed running to convey the sheet (S106), and when the first sheet is detected by the registration sensor (S107), the motor is temporarily stopped. (S108). After that, it is restarted at a low speed according to the image forming timing (S109). The number of ejected sheets + 1 = the set number of sheets is determined (S110), and if not satisfied, low speed traveling is set (S111), and the process returns to step 107 to carry the next sheet. When the last one sheet is determined (S110), the trailing edge of the sheet is detected (S112), and the motor is stopped (S113).

When the motor is capable of feeding the second and subsequent sheets at a high speed, the second and subsequent sheets are also fed at a high speed,
The first sheet may be conveyed at high speed until it is switched to low speed. The control flow in this case is as shown in FIG.
It is realized by changing to the flow shown by. That is, the sheet is first conveyed after being set to high-speed running (S120), and the number of discharged sheets + 1 = the set number is determined (S121). Since it is the first one, it is judged NO in step 121,
Next, it is determined whether or not the first sheet has been switched to a low speed (S125). If it is confirmed that the first sheet has been switched to low speed, low speed running is set (S11
1) The following paper is conveyed at low speed. On the other hand, when the first sheet is not switched to the low speed, the high speed traveling is continuously maintained (S120). When the number of discharged sheets + 1 = the set number is satisfied (S121), that is, when the last one sheet is detected by the registration sensor (S122), the motor is temporarily stopped (S123). After that, it is restarted at a low speed according to the image forming timing (S124). Thereafter, the same processing as in FIG. 4 is executed.

FIG. 6 shows another specific example of the sheet conveying speed of each roll. In this example, as shown in FIG. 7, the paper conveyance path is long in the cabinet 20 shown in FIG.
When the first sheet S1 is being conveyed at a high speed, when the second and subsequent sheets are fed out, the sheet is first fed out at a high speed, and when the first sheet starts to be conveyed by the registration roll 26, the second and subsequent sheets are conveyed. The sheets S2 and S3 are also slowed down. That is, the sheet conveyance control is performed in the single-sheet mode and the multi-sheet mode. This process will be described with reference to FIG.

First, the set number of sheets is confirmed (S13
0), it is determined whether the set number is one (S13).
1). In the case of one sheet, the sheet is set to high speed running to convey the sheet (S132), and when the registration sensor (SNR) detects the sheet (S133), the motor (MOT) is temporarily stopped (S134). After that, it is restarted at a low speed according to the image forming timing (S135). When the rear 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 conveyed at a low speed for the first time (S136), and when the first sheet is detected by the registration sensor (S137),
The motor is temporarily stopped (S138). After that, the system is restarted at a low speed according to the image forming timing (S139). The number of ejected sheets + 1 = the set number of sheets is determined (S140), and if not satisfied, the routine returns to step 136, and the next sheet of paper is continuously conveyed at low speed running. When the last one sheet is determined in step 140 (S140), the trailing edge of the sheet is detected (S141), and the motor is stopped (S14).
2). According to the above embodiment, the FCOT can be shortened by feeding the first sheet at high speed, and the productivity can be improved. Further, while the first sheet is being conveyed to the registration roll 26, there are some other parts of the apparatus main body that are not operating, so that the noise as a whole can be kept low. Furthermore, since the conveying speed of the second and subsequent sheets is set to be low, noise during continuous copying can be reduced.

Next, a description will be given of the paper transport control for making the speed of sending the paper from the specific paper feeding unit higher than the speed of sending the paper from the other paper feeding units. FIG. 9 shows the first of the specific paper feed units
2 shows a paper feed drive system in which a drive system and a second drive system of another paper feed unit are independently provided. In the present embodiment, the paper feeding speed of the first tray (specific paper feeding section) provided in the apparatus main body is set to the second
To the sheet feeding speed of the fourth tray (other sheet feeding section).

The feed motor M1 of the first drive system includes a first sheet feeding device (FDR) 10 and a manual sheet feeding device (M).
SI unit), and the transport roll (T / A Roll) provided on the sheet transport path to the register gate is driven. Further, the feed motor M2 of the second drive system includes the sheet conveying devices (FDR) 12a to 12c of the second to fourth trays, the sheet conveying device 14 in the double-sided mode, and the conveying rolls (T / A Roll) arranged on the sheet conveying path. ) Drive. Here, the paper transport distance from the first tray 9 as a specific paper feed unit to the transfer unit of the process unit is the shortest,
The specific paper feed unit may be any of the second to fourth trays. In this case, the sheet conveying distance from the specific sheet feeding section to the transfer section is not the shortest. FIG. 10 shows a change in the sheet conveyance speed. Note that speed a <speed b, speed a ≧ process speed. In the case of feeding from the first tray 9, as shown in FIG. 9A, feeding is performed from the tray at a speed a or a sheet separating speed, and the leading end of the sheet is conveyed to the transport roll (T /
When the speed reaches A Roll) 1, the speed is increased and the paper is conveyed at the speed b. In the case of feeding from any one of the second to fourth trays 12a to 12c, the tray X is conveyed at a speed a slower than the speed b.

FIG. 11 shows a control block of the paper transport system of the above embodiment. The control block of this embodiment is the control block of FIG. 1 modified to have a function of switching to the first drive system or the second drive system according to tray selection. Here, the fast speed means that the speed is higher than the speed of the second drive system, and the slow speed means that the speed is slower than the speed of the first drive system. The tray selection key 36 is used to select any one of the first tray to the fourth tray shown in FIG. 9, and the first drive system driver 44 and / or
Alternatively, a motor control signal is sent to the second drive system driver 45 to drive the feed motors M1 and / or M2. For example, when the first tray 9 is used as a specific paper feed unit, when the first tray is selected, the CPU 31 outputs a fast speed control signal to the first drive system driver 44, and the feed motor M1 is driven at a high speed. To drive. This makes the first
Paper is ejected from the tray at a high speed. When the second tray is selected, the CPU outputs a slow speed control signal 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 paper is sent out from the second tray at a slow speed.

In the present embodiment, the following effects can be obtained by adopting a configuration in which the feeding speed of the paper from the tray having the shortest paper conveyance distance, that is, the tray closest to the image forming (process) section is higher than that of other trays. Can be expected. Since the paper is carried by a small number of drive systems, even if the paper feeding speed is increased, the maximum noise level of the image forming apparatus becomes equivalent to that of the apparatus that carries the paper at the process speed. The movement of the paper is simpler than the control in which the paper is temporarily stopped and the paper conveyance speed is lowered before the registration when the image formation timing is set, so that the variation in the paper in the pre-registration conveyance system can be suppressed to a small level. Stable paper conveyance is possible,
Since a stable paper gap can be guaranteed and the paper gap target value can be made smaller than before, finally C
It leads to improvement of PM / PPM. Only the delivery of the tray closest to the process section is unique, so the actual movement of the paper is unique from the time it is handled by the tray to the process front side. Therefore, the memory capacity required to set the jam timer value and the like can be smaller than that of other controls. In the conventional control method, the drive system becomes more complicated as the number of tray stages increases, but in this method, the drives other than the tray closest to the process section can be combined into one, so that the mechanism can be simplified.

[0022]

As described above, according to the present invention, since the drive control means for making the conveying speed of the first sheet high and the conveying speed of the second and subsequent sheets low is provided, the FCOT is provided.
The noise during continuous recording can be reduced without slowing down. Also, by making the paper feed speed faster than other trays, the paper can be conveyed with less drive system, so even if the paper feed speed from the tray closest to the process section is increased, the maximum noise of the image forming apparatus is increased. The level is equal to or lower than that of an apparatus that conveys paper at the process speed.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of an example of an image forming apparatus to which an embodiment of a sheet conveyance control device of the present invention is applied.

FIG. 2 is a block diagram of a sheet conveyance control unit according to an exemplary embodiment of the present invention.

FIG. 3 is a diagram showing a change in conveyance speed of the first and second sheets according to the present embodiment.

FIG. 4 is a flowchart for changing the sheet conveyance control for the first sheet and thereafter.

FIG. 5 is a flowchart for carrying out paper conveyance control by changing the portion A in FIG.

FIG. 6 is a diagram showing a change in conveyance speed of the first to fourth sheets according to another embodiment.

FIG. 7 is an explanatory diagram of a sheet conveyance path that can realize the conveyance speed shown in FIG.

FIG. 8 is a flowchart for changing the sheet conveyance control in the single-sheet mode and the 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 independently provided.

FIG. 10 is a diagram showing a change in sheet conveyance speed, FIG. 10A is a diagram showing a relationship between a sheet conveyance speed and a sheet leading end position of a specific sheet feeding section, and FIG.

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 independently provided.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Device 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 unit) , 11 ... Paper trays (other paper feed units) 10, 12,
14 ... Paper transport device, 20 ... Cabinet, 26 ... Registration sensor, S ... Paper

Claims (7)

[Claims] 1. A registration roll for carrying a sheet in accordance with an image forming timing; a carrying roll for carrying a sheet to the registration roll;
In a sheet conveyance control device including drive control means for driving and controlling each roll, the drive control means includes a first drive means that conveys at the same speed as a conveyance speed of the registration roll, and the registration roll. A second driving unit that conveys the sheet at a speed higher than the conveying speed of the sheet, and a control unit that switches the first or second driving unit according to the sheet. A sheet conveyance control device, wherein the first drive means is switched to the second drive means for the first sheet, and the second drive means is switched to the first drive means. 2. The sheet conveyance control device according to claim 1, wherein the control means controls the conveyance of the second and subsequent sheets after the first sheet reaches the registration roll. . 3. The control means controls the second sheet transport control means to transport the second and subsequent sheets at a high speed until the first sheet is switched to the transport speed by the registration roll. The sheet conveyance control device according to claim 1. 4. The control means conveys at high speed by the second drive means in the one-sheet mode, and conveys all the sheets by the registration roll by the first drive means in the plural-sheet mode. The sheet conveyance control device according to claim 1, wherein the conveyance control is performed at the same speed as the speed. 5. An image forming apparatus having a plurality of paper feeding units, wherein first driving means for feeding the paper from the paper feeding unit at a first speed, and feeding the paper at a second speed higher than the first speed. An image forming apparatus comprising: two driving means or a third driving means capable of switching between a first speed and a second speed; and a control means for switching the driving means according to a sheet feeding section. 6. The paper feed unit for feeding the paper by the second drive unit or the third drive unit is provided with a paper feed unit that minimizes at least the paper transport length from the paper feed unit to the transfer unit. The image forming apparatus according to claim 5, wherein: 7. The second driving means or the third driving means for feeding out the paper of the paper feeding portion having the shortest paper conveyance length from the paper feeding portion to the transfer portion, and the driving means of another paper feeding portion. The image forming apparatus according to claim 6, wherein the image forming apparatus is provided independently of the image forming apparatus.