JPS61173261A - Transfer position controlling device of copying paper - Google Patents

Abstract

PURPOSE:To remove completely a transporting error due to a slip, etc., which occur at the time of reopening the transportation by controlling the arrival timing to a transfer position without stopping a copying paper on the transporting path. CONSTITUTION:A transfer position control device is constituted with a picture transfer start time detecting means 51 which detects a timing when a toner image corresponding to the image of an original reaches the transfer position, a copying paper transport timing detecting means 52 which detects the condition of the advance and the delay of the transportation for the copying paper, and a transport speed control means 53 which controls the speed without stopping the transport of the copying paper based upon the information obtained from both means 51 and 52. Thus, since the copying paper is not stopped and the transport timing is controlled, the transporting error at the time of reopening the transportation can be removed, and the transfer position can be controlled with the high accuracy to that extent.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention relates to a transfer method for controlling the transfer position of a toner image to copy paper in a copy machine that transfers a toner image using cut copy paper. Related to position control devices.

``Prior Art'' A copying machine using the principle of xerography forms an electrostatic latent image corresponding to the image of a document on a photoreceptor 2, and develops this to create a toner image.

The toner image is transferred onto copy paper using a transfer device that utilizes corona discharge, fixed by heat or pressure, and then discharged onto a discharge tray or the like as a copy image.

FIG. 9 shows the main parts of a conventionally widely used copying machine. A document guide 12 is disposed at one end of the platen glass 11 of this copying machine, and one end of the document 13 is abutted against and positioned. Mirrors 14 to 17 are located below the platen glass 11.
and an optical lens 18 are arranged, and the reflected light of the original 13 irradiated by a light source (not shown) passes through these optical systems and is exposed to a predetermined position of a drum-shaped photoreceptor 19. The photoreceptor 19 is configured to rotate in the direction of an arrow 21, and when the original 13 is scanned with the aforementioned one end as the leading edge, an electrostatic latent image is formed in the direction shown by a broken line 22. This electrostatic latent image is developed into a toner image, and is placed on a copy sheet 25 at a transfer position 24 located near a transfer device (not shown).
will be transcribed into.

The copy paper 25 cut into a predetermined size is placed in the supply tray 2.
6, and are fed out one by one at a predetermined timing by driving a feed roll 27. The fed-out copy paper 25 is conveyed on the conveyance path 29 and reaches the transfer position 24, but the leading edge of the toner image must reach the transfer position 24 at the same time that the leading edge of the copy paper reaches the transfer position 24.

However, if the copy paper 25 is set in the supply tray 26 with its leading edge not aligned or if it slips between the copy paper 25 and the feed roll 27, it will not be able to reach the transfer position 24 at the desired time. Therefore, conventionally, the copy paper 25 is sent out early and the transport is temporarily stopped on the transport path 29 to control the timing.

Figure 10 shows one of such transfer position control devices, which was developed in 1985.
1-125338. In this device, a movable piece 34 is attached by a plunger 32 of a solenoid 31 and a spring 33 so as to be movable left and right. When one end of the positioning member 36, which is rotatably arranged around the fulcrum 35, is moved in the left-right direction by the moving piece 34, the gate 3 located at the other end of the positioning member is moved.
6A protrudes into or retreats from the copy paper conveyance path 29. The copy sheet first hits a gate (dotted chain line) 36A projecting into the conveyance path 29, and its progress is stopped, and conveyance is resumed when the movable piece 34 moves rightward in the figure.

Next, FIG. 11 shows the main parts of another transfer position control device. A device with such a configuration is disclosed in, for example, Japanese Patent Application Laid-open No. 57
It can be seen in the publication No.-58165. In the apparatus shown in FIG. 11, a pair of transport rolls 38 and 39 are arranged in the copy paper transport path 29. Initially, the rotation of the transport rolls 38 and 39 is stopped, and the copy paper that has been transported onto the transport path 29 is thereby prevented from advancing. The transport rolls 38 and 39 then start rotating at a predetermined timing, and begin transporting the copy paper in exact synchronization with the surface speed of the photoreceptor.

``Problems to be Solved by the Invention'' By the way, in the apparatus of the type shown in FIG. 10, as shown in FIG. The tip is curved to form a loop. gate 36
A denotes transport rolls 43 and 44 provided to transport the copy paper 25 at the surface speed of the photoreceptor after timing adjustment.
is located near. This is to ensure that the transport rolls 43 and 44 start reliable transport before an error occurs in the transport amount of the copy sheet 25 for which the timing has been adjusted.

However, as shown in FIG. 13, the copy paper 25A that has formed a loop at the gate point is sandwiched between the conveyor rolls 43, 44 in a shape 25B1.25C1 that maintains the loop as shown by the two-dot chain line. As time passes, the shape 25B as shown by the solid line changes.
2, and then changes to a shape 25C2 sandwiched between transport rolls 43 and 44. Here copy paper 25
Let ΔR be the error that occurs from the gate point to the conveyance rolls 43 and 44. In this situation, where it is impossible to set the distance d from the gate point to the point where the nip occurs between the two transport rolls 43 and 44 to zero, the error △
R cannot be made zero either. The error ΔR can be expressed by the following equation.

ΔR#1/2αt2...(1) Here, t is the first
This is the time from opening of the gate 36A shown in FIG. 0 or FIG. 12 until the copy paper 25 jumps into the transport roll 43, 44, and can be assumed to take a constant value depending on the device.

α is the acceleration of the leading edge of the copy paper 25. Acceleration α
can be expressed by the following equation.

α=F/M (2) Here, the symbol F indicates the degree of looping of the copy paper 25, the stiffness of the paper, the moisture content, and the conveyance speed until the copy paper 25 reaches the gate 36A. These are related values, and the symbol M is the mass of the copy paper 25. These values have the characteristic of changing for each sheet of copy paper 25, which ultimately increases the range of fluctuation of the error ΔR. Apart from the acceleration α, the conveyance roll 4
3.44 The error ΔR also varies depending on the contact state between the leading edge portion and the roll surface when the copy paper 25 is sandwiched. This amount of variation became larger as the speed of the transport rolls 43, 44 became faster, and had a considerable effect on the transfer position of the toner image on the copy paper 25.

On the other hand, as shown in FIG.
In this method, the transfer position is controlled by turning on and off the drive of the copy paper 25, as shown in FIG. 14, the leading edge of the copy paper 25 comes into direct contact with the transport rolls 38 and 39 and stops. Therefore, the fluctuation in the transfer position due to the acceleration α shown in equation (2) can be suppressed to be smaller than in the apparatus using the former method.

However, a clutch (not shown) was turned on and the conveyor roll 3
When the rolls 8.39 are driven, acceleration is temporarily generated in these rolls, causing slippage between them and the copy paper 25.

As a result, the time it takes for the copy paper 25 to change from the arrangement shown by the solid line in FIG. 15 to the arrangement shown by the dashed-dotted line becomes unstable, which causes the transfer position of the toner image on the copy paper 25 to be inconsistent. Ta.

As described above, in any of the conventionally used apparatuses, errors due to the properties of the copy paper itself occur when the copy paper is restarted to be conveyed. Therefore, it is influenced by various conditions such as the environment, and sometimes large errors occur. In addition, variations in the timing of opening and closing of the gate and the start of driving of the transport rolls also affect alignment of the transfer position as the transport speed of copy paper increases.

In view of these circumstances, it is an object of the present invention to provide a transfer position control device that allows a copy sheet to accurately reach a transfer position at a desired timing and transfer a toner image.

As shown in principle in FIG. 1, the present invention includes an image transfer start time detection means 51 for detecting the time when a toner image corresponding to an image of a document arrives at a transfer position, and the progress or delay of conveyance of copy paper. A copy paper conveyance timing detection means 52 that detects the timing of copy paper conveyance, and a conveyance speed control means 53 that controls the speed of copy paper conveyance without stopping the conveyance of the copy paper based on information obtained from both means 51 and 52 for transfer position control. Provided in the device.

According to the present invention, since the conveyance timing of the copy paper is controlled without stopping the copy paper, conveyance errors upon resumption of conveyance can be eliminated, and the transfer position can be controlled with high precision.

The present invention will be described in detail with reference to Examples below.

FIG. 2 shows the main parts of a copying machine using the transfer position control device of this embodiment. Components that are the same as those in FIG. 9 are designated by the same reference numerals, and their descriptions will be omitted as appropriate. In this copying machine, a drum-shaped photoreceptor 19 is driven by a motor (not shown). Photoconductor encoder 6
1 outputs a photoconductor rotation state signal 62 of a pulse number corresponding to the amount of rotation of the photoconductor 19. The servo encoder 63 detects the amount of rotation of the servo motor controller for driving the transport rolls 64, 65, and outputs a servo motor drive state signal 67 with a corresponding number of pulses. A lead edge sensor 68 is provided near the paper sending side of the transport roll 64.65, and the copy paper 25 sent out from the supply tray 26 by the paper feed device 69 is transferred to the transport roll 64.65.
When the lead edge passes through the lead edge, the leading edge is detected and a lead edge detection signal 71 is output. Further, a light emitting diode 73 is attached to the optical system scanning carriage 72, and the light reflected from the leading edge of the original 13 is reflected onto the mirror 14.
The photo sensor 76 detects the exact timing at which the light is reflected by the light and reaches the exposure point 75.

Of course, such detection of the document scanning start point can also be configured using mechanical detection means such as a microswitch.

The scanning start point detection signal 77 from the photosensor 76 is sent to the registration control circuit together with the photoreceptor rotation state signal 62, servo motor drive state signal 67, and lead edge detection signal 71, which have already been described, and control data 79 output from the main controller 78. 81, the transfer position is controlled manually. The main controller 78 not only sends control data 79 to the registration control circuit 81 but also controls the paper feed device 69 and carriage 72.
Control data 82 and 83 for drive control are also sent.

FIG. 3 specifically shows the main parts of the copy paper transfer position control device. The registration control circuit 81, which performs the central function of this device, is equipped with a dedicated CPIJ (central processing unit) 85.

The CPU 85 is connected to a ROM (read only memory) 87, a RAM (random access memory) 88, and an I10 port 89 through a bus 86.

Here, the ROM 87 is an element in which a program for controlling the transfer position of the copy paper is written, and the RAM 88
is a working memory used when performing a series of data processing. I10 port 89 is programmable timer 9
This is a port for human output of data between the terminal 1 and the resettable count 92.

The programmable timer 91 is a counter loaded with a predicted value of the timing at which the lead edge sensor 68 detects the leading edge of the copy paper 25. Programmable timer 9
1 counts down the photoreceptor rotation status signal 62 at the start of conveyance of the copy paper 25, and sends the counted value ε when the leading edge of the copy paper 25 is actually detected to the bus 86 via the ■/○ port 89. become. The programmable timer 92 is an up/down counter, and has an input terminal IJP for counting up and an input terminal DOW for counting down.
It is equipped with N. Input terminal UP has I10 port 89
A photoreceptor rotation state signal 62 is supplied by a switch S1 operated under the control of the photoreceptor rotation state signal 62. Further, a servo motor drive state signal 67 is supplied from the servo encoder 63 to the input terminal DOWN by a switch S2 operated under the control of the same <I10 port 89. The presettable counter 92 adds and subtracts the pulses input to both terminals UPSDOWN, and converts this value into a digital crew analog converter (DAC).
94.

By the way, the presec pull counter 92, digicrew analog converter 94, adder 95, phase compensation circuit 96, power amplifier 97, servo motor controller, servo encoder 63, and frequency-voltage converter (FVC) 98 form a servo control loop as a whole. It consists of That is, when both switches S1 and S2 are off, the first transport speed data 101 is preset from the I10 port 89 to the presec pull counter 92, and the servo motor 66 is activated based on this data. Driven at high speed. As a result, the copy paper 25 sent out from a paper feed tray (not shown) is transported at a speed approximately twice the circumferential speed of the photoreceptor 190. After the leading edge of the copy paper 25 is detected by the lead edge sensor 68, second conveyance speed data 102 corresponding to the advance or delay of the copy paper 25 at the time of this detection is set in the presec pull counter 92, and this value is As a starting point, control is performed so that the conveying speed of the copy paper matches the circumferential speed of the photoreceptor.

This latter control is called PLL (Phase-Lock).
ed Loop).

First, how to set the first conveyance speed data 1111 in the transfer position control device as described above will be explained with reference to FIG. 4. When the start button (not shown) of the copying machine is pressed to start copying (step ■), the main controller 78 detects this and drives the main motor (not shown) to rotate the photoreceptor 19 at a constant speed (step ■). ). After this, the main controller 7
8 starts up the registration control circuit 81 (step ■).

At the same time, the CPU 85 in the registration control circuit 81 turns on both switches S1 and S2, and starts the program in the servo control loop PLL mode shown in FIG. 3 (steps ① and ②). As a result, phase synchronization is performed such that the frequency of the servomorph drive state signal 67 matches the frequency of the pulsed photoreceptor rotation state signal 62 output from the photoreceptor encoder 61. When a predetermined time has elapsed, step ■; Y), phase synchronization is completed (step ■).

That is, since the photoreceptor 19 is rotating at a constant speed, the output data 104 output from the presettable counter 92
becomes constant. This output data 104 is a preset value (
PD value) is sent to the bus 86 via the ■/○ port 89 and written into the RAM 88 (step ■). In this way, the amount of rotation of the servo motor chronograph corresponding to the circumferential speed of the photoreceptor 19 is detected.

When the preset value is written to RAM88, CPU85
turns off both switches S1 and S2, and loads the first transport speed data (SPDo) 101 into the brisec pull counter 92 as the initial transport speed data (SPD) of the copy paper 25 (step 2). This starts the conveyance speed control of the servo control loop (step ■).

This conveyance speed control is performed on the copy paper 2 as described above.
5 is conveyed at a speed approximately twice the circumferential speed of the photoreceptor 19. Such control is based on the output data 10 that is fixedly output from the Brisec pull counter 92 at this point.
4 as a reference for the conveyance speed. That is, the DigiCrew analog converter 95 receives the first transport speed data 101.
An analog value corresponding to the reference voltage VnAc is output as the reference voltage VnAc, and is compared with the output voltage VFVC of the frequency-voltage converter 98 in the adder 95. Phase compensation circuit 9G
compensates the phase of the output of the adder 95, and the amplifier 97 performs pulse width control to drive the servo motor 66 at a relatively high constant speed.

As a result, the transport roll 64 is driven at approximately the same speed as the initial transport speed (referred to as feed speed) of the copy paper 25 (step 0).

When the registration control circuit 81 is activated and a predetermined period of time has elapsed (step 0; Y), the scan start signal 106 is generated as shown in FIG. Carriage 72
is activated (step 0). Shortly after this, when the carriage 72 reaches the start position for scanning the leading edge of the original 13, the photosensor 76 detects the light emitted from the light emitting diode 73 (step 2).

As a result, the CPU in the registration control circuit 81
85 is interrupted. As an interrupt process, the CPU 85 outputs a predicted value LD for predicting the point in time when the leading edge of the copy paper is detected.
Read from M87 and load it into the programmable timer 91 via the I10 port 89 (step
). The predicted value LD is expressed by the following equation.

LD=XT -XA (3) Here, XT
is the photoreceptor 1 from the exposure point 75 to the transfer position 24 in FIG.
9, and XA is the length along the conveyance path of the copy paper 25 from the detection position of the lead edge sensor 68 to the transfer position 24. That is, assuming that the copy paper 25 detected by the lead edge sensor 68 is conveyed to the transfer position 24 at a speed equal to the circumferential speed of the photoreceptor, the predicted value LD is The value is such that the circumferential length of the photoreceptor 19 from the leading edge 109 of the image 108 to the transfer position 24 is equal to the length XA.

When the predicted value LD is loaded, the programmable timer 9
1 is sequentially subtracted from the photoreceptor rotation state signal 62 (FIG. 5C) having a frequency corresponding to the circumferential speed of the photoreceptor 19 (step [phase]).

On the other hand, when a predetermined period of time has elapsed since the start of the carriage (step 0), the transport control signal 109 (step 0; Y)
FIG. 5b) occurs, and conveyance of the copy paper 25 is started (step @).

In FIG. 5, a solid line 110 represents an example of control of the copy paper sent out by the paper feed device 69. The copy paper 25 sent out by the paper feed device 69 at time t1 is transported at a speed approximately twice the circumferential speed of the photoreceptor, and at time t2, the leading edge of the copy paper 25 passes the transport roll 64, and at time t3, it is detected by the lead edge sensor 68. will be detected (step [phase], Figure 5e). On the other hand, the photoreceptor 19 rotates at a constant speed as shown by a dashed line 112. From the time when the scanning start point detection signal 77 (FIG. 5 d) is output from the photosensor 76, the photoreceptor 1
The leading edge of the image formed on lead edge sensor 9 ideally reaches a rotational position corresponding to lead edge sensor 68 at time t3. This rotational position is a point returned by XA in the circumferential direction of the photoreceptor from the transfer position. In such an ideal state, the copy paper 25 is exposed to the lead edge sensor 68.
If the conveying speed is immediately made equal to the circumferential speed of the photoreceptor 19 at the time detected by t, the leading edge of the copy paper 25 and the leading edge of the image will completely coincide with each other at time t. Since such speed switching is actually impossible, in this transfer position control device, as shown in FIG.
The copy paper 25 is conveyed in the high-speed conveyance control mode in the previous stage, and thereafter the conveyance speed is made to match the circumferential speed of the photoreceptor 19 in the PLL mode by PLL control. FIG. 5f shows such control of the conveyance speed as the signal state of the servomorph drive state signal 67.

By the way, as a premise for starting control in the PLL mode, it is necessary to determine the difference between the predicted value LD and the actual value at the time when the lead edge sensor 68 detects the leading edge of the copy paper 25. Therefore, this transfer position control device reads the actual measurement value LD' of the programmable timer 91 at this time t3 (step 2, 0). Since the count value ε as this value is ideally zero, the count value ε directly represents the error. The actual measurement value LD' and the conveyance speed of copy paper have the following relationship.

ε>0... Faster than the predicted conveyance speed.

ε-0... Same as predicted conveyance speed.

Packing O...The conveyance speed is slower than the predicted one.

The CPU 85 stores this count value ε in the brisec pull counter 9.
2 from the ideal value PDL that should be preset, and preset this in the presettable counter 92 as the second conveyance speed data 102 (step O). Then, both switches S1 and S2 are turned on (step O), and the servo control loop is switched to PLL control (step -). As a result, the conveying speed of the copy paper 25 becomes consistent with the circumferential speed of the photoreceptor 19 at time t4, and step @), and at time t5.
The leading edge of the copy paper reaches the transfer position 24 and the toner image (
image) will be transferred without any problem.

FIG. 7 shows how image and copy paper positions are controlled. In the figure (Δ), the broken line indicates the case where the count value ε is zero. In this case, the lead edge sensor 68
At time t3 when detects the leading edge of the copy paper 25,
Second conveyance speed data 1 corresponding to the circumferential speed of the photoreceptor 19
For example, a numerical value "808" is preset in the brisec pull counter 92 as 02. In the state before this time t3, as shown in FIG. 7(B), the conveyor roll 64
is driven at a high speed approximately twice the circumferential speed of the photoreceptor. Therefore, when both switches S1 and S2 are turned on, the frequency of the servo motor drive status signal 67 output from the servo encoder 63 is higher than that of the photoconductor rotation status signal 62 output from the photoconductor encoder 61, and The sex pull counter 92 counts down. As a result, the peripheral speed of the conveyance roll 64 is temporarily lower than that of the photoreceptor 19, as shown in FIG. 7(B). However, in the PLL control loop, the frequency of the photoreceptor rotation state signal 67 is finally set to the servomorph drive state.

Control is performed to match signal 67. Therefore, the presettable counter 92 counts up again in the direction of the numerical value "808", and synchronization is completed at time t4A shown in FIG. 7 (Δ).

On the other hand, if the copy paper 25 is detected by the lead edge sensor 68 earlier than the predicted time, for example,
Second transport speed data 102 having contents corresponding to the degree is preset in the presettable counter 92. This value is obtained by subtracting the count value ε from the value corresponding to the peripheral speed of the photoreceptor 19. The count value ε is a numerical value” 5
”, in this example, the subtraction is done from the number “808”, and the value “808” is added to Blisec Bull Count 92.
803'' is preset.

Control in this latter case is represented by a solid line in FIG. 7 (Δ). In this case, control is performed such that the speed is inclined toward the lower speed side by a preset initial value, and then convergence to a value "808" corresponding to the peripheral speed of the photoreceptor 19 is performed. The synchronization completion time in this case is expressed as time t4B.

In either case, the conveying speed of the conveying roll 64 is the seventh
As shown in Figure (B), the peripheral speed of the photoreceptor 19 fluctuates in an oscillatory manner from time t3 to time t4, and then settles down to the peripheral speed of the photoreceptor 19. At this time, the count value ε for correcting the conveyance timing according to the preset value set in the presettable count 92.
is selected, and the leading edge of the copy paper 25 and the leading edge of the image match at the transfer position 24.

Now, as the transfer of the toner image onto the copy paper 25 progresses and the trailing edge of the copy paper passes the lead edge sensor 68, the detection operation by this sensor ends at this point (step [phase]). When the detection operation of the lead edge sensor 68 is turned off, an interrupt is generated to the CPU 85. The CPU 85 turns off both switches S1 and S2 as an interrupt process, and sends the first conveyance speed data 1 to the briseck bull counter 92 again.
01 (step O). As a result, the transport roll 64 is again driven at a high speed approximately at the feed speed to prepare for transporting the next copy sheet (step [phase]
).

"Modified Example" Although the transfer position control device using a drum-shaped photoreceptor has been described above, the present invention can also be applied to a copying machine using a belt-shaped photoreceptor. Some types of copying machines that use this belt-shaped photoreceptor transfer the image by aligning the trailing edge of the image with the leading edge of the copy paper, but it goes without saying that the present invention can be applied to this as well. be.

FIG. 8 shows the main parts of such a copying machine.

In this copying machine, an original 13 placed on a platen glass 11 is exposed to flash light, and an image (electrostatic latent image) is formed on a belt-shaped photoreceptor 121 at once using a lens (not shown). It is assumed that the photoreceptor 121 rotates in the direction of an arrow 122 and the toner image is transferred to the copy paper 25 at a transfer position 124. In this case, the transfer is performed from the rear end opposite to the leading edge of the original 13 positioned by the original guide 12. That is, the transfer position is controlled so that the trailing edge of the image (toner image) coincides with the leading edge of the copy paper 25.

In order to enable such control, in the transfer position control device of this modification, first and second tail edge sensors 126 and 127 are arranged before and after the conveyance roll 64, which is driven in two types of control modes. ing. The first tail edge sensor 126 detects the copy paper 2 that has been sent through the conveyance path 128.
This sensor detects the trailing edge of the copy sheet 5 and drives the conveying roll 64 at a relatively high speed in preparation for conveying the next copy sheet, as shown in steps [phase] to [phase] in FIG. Further, the second tail edge sensor 127 is also connected to the conveyance path 128.
The trailing edge of the copy sheet that has been fed is detected, and the count value ε is read as shown in steps [phase] to O in FIG.

That is, in this transfer position control device, the length in the circumferential direction of the photoreceptor 121 from the leading edge of the image 129 during exposure to the transfer position 124 is defined as Assuming that the length of path 128 is XA, transport roll 64 is placed in the high speed transport control mode (see FIG. 5g) until second tail edge sensor 127 detects the trailing edge of copy sheet 25. Then, when the trailing edge of the copy paper 25 is detected, the second transport speed data 102 based on the count value ε is transmitted to the presettable counter 92 (the third
Thereafter, the transport roll 64 will be driven in the PLL control mode (see figure 5g).

As described above, the PLL control is canceled when the first tail edge sensor 126 detects the trailing edge of the copy paper 25.

Of course, conveyance control other than such transfer position control is also possible. For example, the same sensor as the first tail edge sensor 126 detects the leading edge of the copy paper and performs PLL control;
Furthermore, by performing similar control with the second tail edge sensor 127, accurate positioning is possible even with larger conveyance errors.

In the embodiment and the modified example, the control has been explained focusing on only one sheet of copy paper, but there are cases where a plurality of sheets of copy paper are continuously transported along the transport path with a short distance between them. In such a case, a plurality of programmable timers are provided to set the predicted value LD for each copy paper and to set the count value ε.
All you have to do is read out the .

"Effects of the Invention" As explained above, according to the present invention, the timing at which the copy paper reaches the transfer position is controlled without stopping the copy paper on the conveyance path. This makes it possible to control transport with extremely high precision.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the principle of the present invention, Figures 2 to 7
The drawings show one embodiment of the present invention, of which Fig. 2 is a schematic configuration diagram of a copying machine, Fig. 3 is a diagram showing main parts of a transfer position control device, and Fig. 4 is a diagram showing a first conveyance speed. A flowchart showing the data setting operation, FIG.
Flowchart showing the operation corresponding to the figure, Figure 7 (A) is PL
An explanatory diagram showing changes in the output data of the presettable counter in the L control; FIG. FIG. 9 is a schematic configuration diagram showing the general configuration of a copying machine, and FIG. 10 is a schematic configuration diagram showing the main parts of a conventional transfer position control device to explain the modification. FIG. 11 is a diagram showing the main parts of another conventionally used transfer position control device. FIG. 12 is an explanatory diagram showing the state of the copy sheet hitting the gate.
Figure 3 is an explanatory diagram showing the principle of error generation when using gates. FIG. 14 is an explanatory diagram showing the stopped state of the copy paper in the transfer position control device shown in FIG. 11, and FIG. 15 is an explanatory diagram to explain the error caused by the transfer position control device shown in FIG. 14. It is. 11...Platen glass, 12...Document guide, 13...Document, 19.121...
... Photoreceptor, 24.124 ... Transfer position, 2
5... Copy paper, 51... Image transfer start time detection means, 52... Transfer timing detection means, 53... Conveyance speed control means, 61. ...Photoconductor encoder, 63 ... Servo encoder, 64 ... Conveyance roll, 66 ... Servo motor, 85 ... CPU. 91...Programmable timer, 92...
...Presettable counter.

Claims (1)

[Claims] 1. Set the original on the platen with one side aligned with a fixed reference line, and transfer the toner image formed on the photoreceptor corresponding to the image of this original onto copy paper at a predetermined transfer position. In a copying machine, an image transfer start timing detection means detects the timing at which a toner image formed on a photoconductor corresponding to a document reaches the transfer position, and a copy paper until the copy paper reaches the transfer position. A copy paper transport timing detection means detects the arrival of one end of the copy paper at a fixed position on the transport path, compares the detected arrival time of the copy paper with an ideal time, and transports the copy paper according to these differences. 1. A transfer position control device for copy paper, comprising a conveyance speed control means for controlling the conveyance speed of the copy paper without stopping the copy paper and causing the copy paper to reach the transfer position at a predetermined timing.