JPS60258573A - Transfer device - Google Patents

Abstract

PURPOSE:To prevent unnecessary feeding of transfer material and to record information in a desired position at high speed with high quality by moving the transfer material for a prescribed length in the direction opposite to the advance direction after transfer. CONSTITUTION:A photosensitive drum 7 is driven by a driving motor 33, pulleys 40 and 41, a timing belt 44, and gears 46 and 47. Meanwhile, the driving motor 33 carries a transfer paper 15 by pulleys 42 and 43, a timing belt 45, a clutch 37, and a tractor 16. The transfer paper 15 is fed synchronously with the photosensitive drum 7 by the clutch 37 controlled by the pulse signal generated by a rotary encoder 35. When recording information is broken, the clutch 37 is released, and a reversing clutch 38 is made conductive, and the driving force of a paper returning motor 34 is transmitted through gears 50, 51, 52, and 53 to reverse the tractor 16; and when the transfer paper is returned for a prescribed extent, an encoder 36 counts this extent to stop the transfer paper 15. When information is recorded on the photosensitive drum 7 again, the clutch 37 is operated to restart carrying the transfer paper.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transfer device in an electrophotographic recording device or the like.

Conventionally, mechanical impact printers have been widely used as output devices for electronic computers and the like. 2. Description of the Related Art Recent advances in electronic technology have increased the processing power of arithmetic units and storage devices, and as a result, there is a demand for output printers with capabilities that exceed those of conventional mechanical impact printers. Various non-impact printers have been developed to meet these demands, but among them, printers that use information from a computer as an electrostatic latent image are particularly popular due to their high speed, print quality, and low tenning costs. This electrostatic latent image created on an image support such as a photoreceptor is developed with toner, the developed image is transferred to plain paper, and the toner image on the plain paper is fixed and output. So-called transfer-based electrostatic recording and electrophotographic recording are excellent.

In this method, a long continuous paper is generally used as the transfer material from the viewpoint of reliability in paper handling. When long paper is used, when information is sent intermittently or when writing of information is interrupted, it is necessary to stop running the transfer paper and separate the transfer paper from the latent image support. Furthermore, when writing of information is resumed, it is necessary to start running the transfer paper and bring the transfer paper into contact with the latent image support.

At this time, the drive system starts and stops feeding the transfer paper.

Since the running system requires time to rise and fall, transfer failure occurs at the start and end of transfer, resulting in damage to the transferred image. To solve this problem, it is necessary to provide blank spaces between the intermittent groups of information being transcribed, but since the paper has to be fed further north than necessary, paper is wasted or cannot be recorded in the desired position. This inconvenience arises. Further, since rise and fall times are required for the contact and separation of the transfer paper contacting means, the paper is fed during this time, causing the above-mentioned inconvenience.

SUMMARY OF THE INVENTION An object of the present invention is to provide a recording apparatus that eliminates the above-mentioned drawbacks, eliminates wasteful feeding of transfer paper, and records information at a desired position at high speed and with high quality. That is, in a device that transfers an image formed on an image support onto a conveyed long transfer material, after the transfer to the transfer material is completed, the transfer material is moved in a direction opposite to the forward direction of the transfer material. It is characterized by having means for moving by a predetermined length.

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

FIG. 1 is a schematic diagram for explaining the operation of an embodiment using an electrophotographic method. A laser beam 2 oscillated by a laser oscillator 1 is modulated according to an input signal from an information output device 56 to a modulator 3, and then scanned by a rotating polygon mirror 4 onto a drum-shaped photoreceptor 7 rotating in the direction of the arrow. is imaged and exposed. Note that other means such as a cathode ray tube, a plasma display, etc. can also be used for optical image exposure.

It is possible to apply various electrophotographic pro-7s that have been proposed in the past to the present invention. The present invention will be described in detail.

The photoreceptor 7 basically has a conductive support, a photoconductive layer, and an insulating layer on the surface, and is uniformly charged in advance by a second corona charger 8, and then subjected to optical image exposure by the laser beam. At the same time, an AC corona discharge is performed by an AC corona discharger 9, and the entire surface of the photoconductor 7 is uniformly exposed by a full-surface exposure lamp 10. As a result, an electrostatic latent image according to the above-mentioned light image is formed on the photoconductor. 7 formed on the surface.

This electrostatic latent image is formed by charged colored particles (toner) in the developing device 11.
It is developed with a developer mainly consisting of , and is visualized. The developed image is transferred to a fan, which is a transfer material, by a tractor 16 having a sprocket bin that engages with a sprocket on the transfer material side, and a first intermediate conveyance device 21m having a suction fan 32 and a perforated belt 31. Transfer roller 1 is placed on hold paper 15 (hereinafter also referred to as transfer paper or simply paper).
9.21 and the electric field from the transfer corona discharger 20 to perform the transfer.

When the information recording on the photoreceptor 7 is finished and the last part of the image has been transferred to the transfer paper, the transfer rollers 19 and 21 are released, the corona discharge for transfer is stopped, and the transfer paper 15 is separated from the photoreceptor 7. At 1 (the tractor 16 starts to rotate in reverse. As a result, the transfer paper on the conveyor belt 31
A tension is applied to the suction fan 32 to move it forward.
The transfer paper 15 is peeled off from the surface of the photoreceptor. Further, at the same time, the backward tension applied to the transfer paper due to the reverse rotation of the tractor 16 is stronger, so the transfer paper 15 is moved backward and stopped after being returned by an amount sufficient to prevent misalignment and blurring when restarting. Thereafter, when the image is recorded on the photoreceptor 7 again, the developed image on the photoreceptor 7 and the transfer rollers 19 and 21 press the transfer paper 15 against the photoreceptor 7 again, and apply voltage to the transfer corona discharger 20. was applied, and the paper 1 was transferred last time.
The trailing edge of the image on the photoreceptor 7 and the leading edge of the developed image on the photoreceptor 7 are continuous, that is, the developed image on the photoreceptor 7 is transferred onto the transfer paper 15 as one continuous image due to misalignment or blurring of the image seam. The image is transferred and recorded.

FIG. 2 is an enlarged view of the transfer section. A first transfer roller 19 and a second transfer roller 21 whose surfaces are covered with insulating rubber.
is close to the transfer corona charger 20, and spread of corona charge. In addition to preventing scattering and blurring of the image, by pressing the transfer paper against the photoreceptor, it prevents defects due to the transfer paper lifting, especially when using fan-hold paper as the transfer paper, image transfer defects due to lifting from the photosensitive plate at the perforated area. It functions to perform stable and uniform transfer.

On the other hand, during non-transfer, the first transfer roller 19 and the second transfer roller 21 are released from the pressure contact of the transfer paper 15 against the photoreceptor 7 by the first plunger 29 and the second plunger 30, and are positioned as shown by the broken line in the figure.

Furthermore, at the same time, the upper guide plate 28 incorporated in the same substrate as the first transfer plate 19 and the hair 1 (not shown) moves in the direction of peeling off the transfer paper 15 from the photoreceptor 7 by releasing the first plunger 29, so that the transfer paper 15 is transferred. To ensure that paper 15 is peeled off.

FIG. 3 is a schematic diagram illustrating a mechanism for transporting and returning transfer paper. In FIG. 3, the photosensitive drum 7 is driven by a drive motor 33,
Pulley 40.41, timing belt (or chain)
44, and driven by gears 46 and 47,
Furthermore, the drive motor 33 is connected to pulleys 42, 43. The transfer paper 15 is transported by a timing belt 45, a transfer paper transport clutch (for example, a micro powder clutch) 37, and a tractor 16. The transfer paper 15 is fed in synchronization with the photosensitive drum 7 by the action of a clutch 37 that is controlled based on a pulse signal emitted by a rotary encoder 35 (described later), but if the recorded information is cut off quickly, the transfer clutch 37
7 is released, the reversing clutch 38 is turned on, and the drive of the paper return motor 34 is transmitted through the gears 50, 51, 52, 53, the tractor 16 is reversed, and the transfer paper 15 is returned. When the rotary encoder 36 counts that the transfer paper 15 has been returned by a predetermined amount, the stop clutch 39 is activated and the transfer paper 15 is stopped. When information is recorded on the photoreceptor again, the conveyance latch 37 is activated by the signal from the quadri-encoder 35, and synchronized conveyance of the transfer sheet is resumed.

@3 In Figure 3, transport and return by the tractor 16 when the transfer paper 15 is fan-hold paper has been explained, but the tractor may be carried out by a pair of rollers, and this is particularly effective when the transfer paper is roll paper. It is.

On the other hand, after the transfer is completed, the colored particles (toner) remaining on the photosensitive drum are removed by a cleaning device 12 in preparation for the next electrostatic latent image forming process.

The transfer paper that has passed through the transfer process is sent to a first intermediate conveyance device 22, a buffer device 23, a second intermediate conveyance device 24, and a heat roller type fixing device 25. The speed of the transfer paper up to the first intermediate conveyance device 22 is determined by the operation of the paper feed tractor 16.
It is perfectly synchronized with the movement of the photoreceptor. On the other hand, the speed of the transfer paper passing through the fixing device due to thermal changes in the diameter of the fixing roller and the meandering correction operation of the transfer paper in the second intermediate conveyance device 24 is slightly different from the paper feeding speed of the paper feeding tractor 16. different. If the transfer paper is long continuous paper, these minute errors will accumulate and cause the transfer paper to break or damage to the conveyance system.

This may cause the inconvenience of stagnation in the middle of the process. Buffer device 2
In step 3, the slack in the transfer paper is detected, and when the slack becomes larger than the specified value, the rotation speed of the fuser roller is increased.
The above-mentioned disadvantages are solved by controlling the rotational speed of the fixing device roller to be lowered when the slack becomes smaller than a specified value. Further, in the fixing device, the transfer paper is conveyed by two rollers while applying heat and pressure. At this time, the transfer paper is slightly skewed due to minute differences in the balance of pressure in the direction of the rotation axis, differences in roller diameter in the direction of the rotation axis, left and right imbalances in the expansion and contraction of the transfer paper, and the like. In the case of long continuous paper, minute amounts of skew are accumulated to a value that cannot be ignored. In the second intermediate conveyance device 24, the amount of skew is accumulated by detecting the skew of the transfer paper and correcting it by changing the suction amount of the suction device and controlling the left and right balance of back tension. to prevent

FIG. 4 shows the fixing device in detail.

The transfer paper 15 having the transferred powder image on its surface is fixed and conveyed while being applied with heat and pressure by a fixing roller 61 and a pressure roller 64. The paper discharge rollers 77 and 78 always apply tensile strength to the transfer paper 15 with a constant torque. The heating rollers 62 and 63 rotate while contacting the fixing roller 61 and apply heat to the fixing roller. Rotational drive is applied only to the fixing roller 61 by a drive motor (not shown). The heating rollers 62 and 63 and the pressure roller 64 follow the fixing roller. The fixing roller 61 is constructed by adhering heat-resistant thick releasable rubber (such as room temperature vulcanizable silicone rubber) to the surface of a metal cylinder.

The pressure roller 64 is constructed by adhering a thin heat-resistant elastic body to a metal cylindrical surface. The heating roller 62.63 includes an infrared heater 79.80 inside an aluminum cylinder whose surface is plated with chrome.

In the standby state where the transfer paper 15 is not running, the pressure roller 64 is separated from the fixing roller 61, and the transfer paper is also
It is separated from the fixing reeler 61. Further, the auxiliary heater 63 is also separated from the fixing roller 61. heating roller 62
contacts the fixing roller 61 and rotates together, applying heat to the surface of the fixing roller. The temperature on the surface of the heating roller 62 is detected by the thermistor 72 in seconds, and the power applied to the heater 79 is controlled to keep the surface temperature constant.
The surface temperature of 1 is kept constant. In addition, the fixing roller 61
The surface temperature of the auxiliary heating roller 63 that is not in contact with the auxiliary heating roller 63 is similarly maintained at a constant value. These temperature controls are performed by a temperature control circuit 74 in a known manner.

The fixing operation is started as follows. First, the rotation of the fixing roller 61 is stopped, and then the pressure roller 64 is pressed against the fixing roller 61 via the arm 69 by the operation of the air cylinder 68.

Therefore, the transfer paper 15 is also pressed against the fixing roller. When the pressurizing operation is completed, the fixing reeler starts rotating. At the same time, the auxiliary heating roller 63 is pressed against the fixing roller 61 via the arm 65 by the force of the air cylinder 66. This functions to supply the heat carried away by the transfer paper 15 to the surface of the fixing roller 61 during the fixing operation, thereby keeping the surface temperature constant.

The fixing operation is completed in the following order. Fixing roller 61
After the rotation of the fixing roller 61 is stopped, the auxiliary heating roller 63 is moved away from the surface of the fixing roller 61 by the action of the air cylinder 66, and the pressure roller 64 is further moved away from the fixing roller 61 by the action of the air cylinder 68. At the same time, the separation pieces 7 and 5
The operation of the solenoid 76 causes the transfer paper 15 to be knocked off the surface of the fixing roller 61 . The transfer paper is
Back tension and discharge roller 7 by the second intermediate conveyance section
7.78, the tensilon comes to the position shown by the dashed dotted line. When the transfer paper is separated, the fixing roller 61 starts rotating again. Thus, the process returns to the standby state.

Through the above-described series of operations, even when the transfer paper runs intermittently, complete fixing is performed without causing problems such as unfixed areas, misalignment of images, and burnt transfer paper. Air is fed into the air cylinders 66 and 68 via a compressor 71 and solenoid valves 69 and 70. The operation of the air cylinders 66, 68 is controlled by switching the solenoid valves 69, 70 between a state in which air is fed into the air cylinder and a state in which the air in the air cylinder is released.

The above-mentioned sequence of light image exposure, latent image formation, development, transfer, and fixing and the timing control of the driving section necessary therefor are performed by a control circuit 57 (FIG. 11).

FIG. 5 shows a timing chart for explaining the relationship between the main print signals and the operation of the drive unit. First, the power is turned on to the apparatus, and preparations such as preheating the fixing device and loading the transfer paper into a predetermined position are completed. Here, the first flash information output device 5
Reference numeral 6 denotes a computer output device, which sends a PRINT signal to a control circuit 57 on the recording device side when information to be recorded is prepared. Control circuit 5 by PRINT signal
Step 7 turns on the power to the motor that rotates the photosensitive drum.

At the same time, each charger except the transfer charger 20, the developer, the cleaning device, and the lamps start operating to prepare for latent image formation (pre-rotation).

When the forward rotation is completed (dA), DATA READY
A signal (first control signal) is sent from the control circuit 57 to the information output device 56 . The information output device rrt56 is a DA
If the TA READY signal is 1", data transfer starts. During data transfer, the DATA signal is 1".
At the same time, a necessary modulation signal is sent to the modulator 3.

Simultaneously with the rise of the DATA signal, the beginning of the information to be recorded is exposed onto the photosensitive drum 7 at exposure position 1 (the position of the AC charger 9) (FIG. 1). This leading edge becomes a high-contrast electrostatic latent image by full-surface exposure, and when it is developed and reaches the transfer position, the transfer paper contacts the photosensitive drum and starts running at the same speed as the circumferential speed of the photosensitive drum, and at the same time A voltage is applied to the transfer charger. If the start of the transfer paper running, the start of the movement of the transfer roller to the contact position, and the start of the transfer corona generation are sufficiently short, dB=dC=d
D=time for the photosensitive drum 7 to rotate from the exposure position to the transfer position. However, in order to allow practical values of these rise times (several ms to 100 ms) and to ensure complete transfer, the dB (second control signal) is set in consideration of these rise times. dCldD is determined.

These relationships will be explained with reference to FIG.

In order for the transfer to be carried out completely (K), as mentioned above, the speeds of the photosensitive drum and the transfer paper must match during the transfer.
It is necessary that the transfer paper and photosensitive drum are in contact and that the transfer corona has sufficient strength.In order to prevent the toner image from scattering, the transfer corona must be in contact with the photosensitive drum before the transfer paper comes into contact with the photosensitive drum. Must not be given.

In order to satisfy this condition, first, the speed of the transfer paper (the speed of the tractor) is kept constant, then the transfer paper is brought into contact with the photosensitive drum, and then a transfer corona is applied. This series of operations creates blank areas on the transfer paper that cannot be transferred.

In order to minimize this blank space, d
Determine B, dC, and dD. In this way, by giving optimum timing to energize the transfer paper feeding means, transfer paper pressure contact means, and transfer electric field applying means, taking into account the respective rise times of the transfer paper feeding means, transfer paper pressure contact means, and transfer electric field application means, the non-transferable area can be fixed. can be minimized.

Similarly, at the end of transfer, the timing for releasing the energization dH%d11 takes into consideration the falling time of each of the above-mentioned means.
dJ is determined (Figure 7). Rising and falling times: Tractor: 7-10m5, Transfer roller: 30-40m
m5, transfer corona: 80 to 100 m5, and under the conditions of 6 o'clock and a circumferential speed of the photosensitive drum of 2000 inches/min, the blank space at the start and end of transfer could be within IA inches, respectively. In addition, in order to make the blank area smaller or zero, the transfer paper is moved back by the amount of the blank area when the transfer is completed, as described above.

Furthermore, in the fuser, when the transfer paper is fed intermittently, a series of operations are performed according to the sequence described above in order to complete the fixing, but the rotation of the fixing roller starts and stops. If the rise time and fall time of the pressurization and release of the pressure roller are not taken into consideration, the difference in the conveyance amount of the transfer paper by the tractor and the fixing device will exceed the tolerance absorbed by the buffer device 123, and the transfer paper will break. Something like that happens. FIG. 8 shows a preferable relationship between the movements of each element in the fixing device when the transfer is started, and FIG. 9 shows the movement when the transfer ends.

In this way, a series of recording operations is completed, and the PRINT signal from the information output device becomes °0''. However, the control circuit maintains the print ready state for a while (dO) and outputs the DATA READY signal. Set it to 1”.

If the PRINT signal becomes 11'' again during this period, information can be written immediately without requiring the pre-rotation time (dA).
If the NT times signal does not become "1", a sequence for stopping the photosensitive drum is performed (dP), the photosensitive drum is stopped, and the process returns to the initial waiting state. dB shown in Figure 5
1dC%dD, dE, dF.

dG predetermines the pulses of the rotary encoder 35, which generates the number of pulses proportional to the amount of rotation of the photosensitive drum connected to the rotating shaft of the photosensitive drum, based on the rise of the DATA signal from "0" to "1'". It can be given with high accuracy by counting the number of dH,
dI, dJ, dK, dM.

Similarly, dN is given in seconds by counting a fixed number of pulses from the rotary encoder 35 with reference to the fall of the DATA signal from @1'' to 102. The figure shows an embodiment of a circuit for generating drive signals for each of the above-mentioned means.

The rotary encoder 35 (FIG. 3) generates a series of pulses by photoelectrically detecting the holes using a large number of large discs provided on the rotating shaft of the photosensitive drum.

Pulses are generated repeatedly by the rotation of the photosensitive drum via the rotary encoder 101 and are input to the gate circuit 102 . The pulse passing through the gate 102 is sent to the counter 104.
and counted. Since the photoreceptor is endless, there is no need to apply a gate depending on the drum position. Setting devices 107 and 109 that set this count value and each drive machine timing
The comparators 106 and 108 are used to determine whether or not the data matches.

When they match, matching pulses dBC and dHC are generated.

103 gates the pulse when the counter reaches the maximum value 10
The circuit 103 is necessary because, for example, if the counter is for two-digit counting, the drum pulse reaches 99, returns to 0, and starts counting again, so the matching pulse is in the same mode. There is a possibility that it will come out many times, and this is to prevent this. 110 is an information output device 56
The print mode signal CMO1CMI as shown in Figure 5 is generated by the "PRINT" and "DATA" signals sent from
, 0M2 and data rising signal TRA1 falling signal T
The print mode generating circuit for generating RB is composed of two input signal feeding gates and a well-known circuit for detecting the leading and trailing ends of the signal DATA. For example, DataReady
Assuming that the time from the rise of the signal until the data is sent out is approximately the same, this can also be shown in FIG.

FIG. 13 shows an example of 120 in FIG.

105 is TRA on 0RIFil road.

Counter 104 is reset from TRB k and gate 10
2 is opened.

Next, the operation sequence of the tractor (in order) for paper feeding will be explained using an example (FIG. 11). As described above, when the PRINT signal is sent and the drum rotates, drum pulses are sent from the rotary encoder.

When the DATA signal is sent after DATA READY turns on, a TRA pulse is sent from the mode generator 110, clears the counter 104, opens the gate 102, and generates the mode signal CMI. When the count value of counter 104 matches the dB value of setter 107, comparator 106 sends a dBC pulse. JK flip-flop 113 is set when dBC and CMI match. When the counter 104 reaches the maximum value, a coincidence pulse is generated from the counter 103, the gate 102 is closed, and the counter 104 stops advancing.

Hold this state until the DATA signal disappears, and
When the signal disappears, a TRC signal is output, counter 104 is reset, and game 102 is opened. On the other hand, mote generator 1
From 10 onwards, the mode signal CM2 is output. counter 10
4 advances and when it matches dH of the setter 108, a match output dHc is output. With this, J
K flip meeting flop 113 is reset and tractor (
) The drive signal disappears and feeding stops. Similarly, when the DATA signal is generated again, a tractor drive signal is generated with a delay of dB to start feeding, and the tractor drive signal disappears with a delay of dH. Signals for each drive machine other than the tractor will be similarly explained.

As described above, according to the present invention, by moving the transfer material by a predetermined amount in the direction opposite to the forward direction of the transfer material after completion of transfer, wasteful feeding of the transfer material can be prevented and information can be recorded at a desired position. .

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an example of the recording apparatus of the present invention, FIG. 2 is a sectional view of the transfer section in FIG. 1, FIG. 3 is a schematic diagram of the transfer material feeding drive section, and FIG. 4 is a fixing device. 1, 7 is a photosensitive drum, 15 is a transfer paper, 16 is a tractor, 20 is a transfer charger, 25 is a fixing roller, and 35 is a rotary encoder. . Applicant Canon Co., Ltd. %q Figure

Claims (1)

[Scope of Claims] In a device for transferring an image formed on an image support onto a conveyed long transfer material, after the transfer to the transfer material is completed, the transfer is performed in a direction opposite to the forward direction of the transfer material. A transfer device characterized by having means for moving a material by a predetermined length.