JPH052995B2 - - Google Patents

Description

[Detailed description of the invention] Technical field The present invention relates to an electronic copying machine.

Prior art As an electronic copying machine, one
The transfer paper is fed by a pair of registration rollers, and the rotation of the registration rollers is started at the same time as image formation on the photoreceptor begins, aligning the toner image on the photoreceptor with the transfer paper. something is known.

However, this electronic copying machine has a drawback that the position of the transferred toner image on the transfer paper may not be constant because the transfer paper tends to slip on the registration roller when the registration roller starts rotating. Further, in the electronic copying machine described above, the circumferential speed of the photoreceptor and the transport speed of the transfer paper are set to be the same. Therefore, the distance from the exposure position to the transfer position and the distance from the registration roller to the transfer position must be the same. In recent years, as copying machines have become more compact, the diameter of photoreceptors has been reduced. When the diameter of the photoreceptor is made smaller, the exposure-to-transfer distance becomes smaller. Accordingly, the registration rollers must also be moved closer to the transfer position. However, there are various components around the transfer position, and there is no room to install the registration rollers close to the transfer position. Therefore, it is necessary to adopt a configuration in which the distance from the exposure position to the transfer position is different from the distance from the registration roller to the transfer position. Even if the distance between the two is different like this,
It is desired to obtain the best copy by keeping the transfer position of the transferred toner image constant.

Purpose An object of the present invention is to provide an electronic copying machine that can maintain a constant position of a transferred toner image on a transfer sheet.

Configuration The present invention will be described in detail based on the embodiments illustrated below.

In FIG. 1, reference numeral 1 indicates a drum-shaped photoreceptor, and this photoreceptor 1 is rotated at a predetermined circumferential speed in the direction of arrow a. Around this photoreceptor 1, a charging device A, an exposure device B, a developing device C, a transfer device D,
Paper feeding device E, transfer paper conveying device F, fixing device G, paper ejecting device H, cleaning device I, and static eliminator J
is located.

A contact glass 2 is placed above the exposure device B, and an original 3 is placed on the contact glass 2. The exposure device B includes an illumination lamp 4, a reflector 5 that reflects light from the illumination lamp 4 toward the contact glass 2,
The first mirror 6, the second mirror 7, and the third mirror 8
, a lens 9 , a fourth mirror 10 , a fifth mirror 11 , a sixth mirror 12 , and an aperture member 13 . The image light from the document 3 is irradiated onto the photoreceptor 1 through the first mirror 6, second mirror 7, third mirror 8, lens 9, fourth mirror 10, fifth mirror 11, and sixth mirror 12. . The illumination lamp 4, reflector 5 and first mirror 6 are moved in the direction of arrow b when forming an image on the photoreceptor 1, and
In synchronization with these, the second mirror 7 and the third mirror 8 are moved in these moving directions at a speed ratio of 2:1, and the image light of the original is projected onto the photoreceptor 1.
An electrostatic latent image is formed on the photoreceptor 1. Next, when the irradiation lamp 4, reflector 5, first mirror 6, second mirror 7, and third mirror 8 (hereinafter referred to as "scanning optical system members") reach the return position, they return in the direction opposite to the arrow b direction. to return to the home position.

The developing device C applies toner having an opposite polarity to the electrostatic latent image on the photoreceptor 1 to form a toner image on the photoreceptor 1 .

The paper feeding device E includes a cassette 15 disposed at a predetermined distance from the photoreceptor 1 and containing a plurality of transfer sheets 14, and a cassette 15 rotatably disposed inside the cassette 15 and containing a plurality of transfer sheets 14. a rotating bottom plate 16 on which the rotating bottom plate 14 is placed; a spring 17 disposed between the rotating bottom plate 16 and the bottom plate of the cassette 15 and pressing the rotating bottom plate 16 upward; A paper feed roller 18 disposed above the front part, a friction pad 19 elastically pressed against the lower part of the paper feed roller 18,
It consists of a pair of registration rollers 20 arranged between the paper feed roller 18 and the photoreceptor 1, and a guide plate 21 arranged between the paper supply roller 18 and the registration roller 20.

The transfer paper 14 in the cassette 15 is pressed against a paper feed roller 18 by the pressing force of a spring 17. When this paper feed roller 18 is feeding paper,
When the transfer paper 14 is rotated in the direction, the transfer paper 14 is fed in the direction of the registration roller 20 by rotational force and frictional force. The friction pad 19 prevents a plurality of transfer sheets 14 from being fed simultaneously by the sheet feed roller 18. A paper sensor 22 is arranged between the paper feed roller 18 and the registration roller 20. The paper sensor 22 includes a light emitting element, a light receiving element, etc., and detects the leading edge of the transfer paper 14 fed from the paper feed roller 18. After a certain period of time after this paper sensor 22 detects the leading edge of the transfer paper 14, the driving force to the paper feed roller 18 is cut off, and the transfer paper 14 comes into contact between the non-rotating registration rollers 20 and a little It is stopped in a bent state. The registration rollers 20 start rotating after keeping the transfer paper 14 on standby for a predetermined time and send the transfer paper 14 in the direction of the transfer paper conveying device F.

The transfer paper conveyance device F includes a loop-shaped conveyance belt 23 made of a dielectric material, a driving roller 24 and a driven roller for moving the conveyance belt 23 in the direction of arrow d at the same speed as the circumferential speed of the photoreceptor 1. A roller 25 , a deviation correction roller 26 for correcting the deviation in the position of the conveyor belt 23 , a roller position adjustment means 27 for adjusting the position of the deviation correction roller 26 , and a transfer roller 25 sent from the registration roller 20 . a charging device 28 that charges the paper 14 and brings it into close contact with the conveyor belt 23 by electrostatic force;
A static eliminator 29 for removing electricity from the transfer paper 14 after the toner image has been transferred in order to separate the transfer paper 14 from the conveyor belt 23; and a paper for separating the transfer paper 14 after the toner image has been transferred from the conveyor belt 23. The separation member 30, the cleaning member 31 that cleans the conveyance belt 23, the static eliminator 32 that neutralizes the portion of the conveyance belt 23 that has been charged by the transfer device D, and the toner image not transferred to the transfer paper 14. A time sensor 34 detects when the detected piece 33 fixed to the conveyor belt 23 passes at a certain time.
and the detected piece 3 fixed to the conveyor belt 23.
5, the deviation sensor 36 detects that the position of the conveyor belt 23 is deviated from the proper position.

The transfer paper 14 sent from the registration roller 20 is charged by a charging device 28, brought into close contact with the conveyor belt 23 by electrostatic force, and moved in the direction of arrow d. Next, the transfer paper 14 is moved in the direction of arrow d by the conveyor belt 23, and the transfer paper 14 is transferred to the photoreceptor 1 and the transfer device D.
When the transfer device D passes between the conveyor belt 2 and
3 and has a charge due to electrostatic force.
The toner image is transferred onto the transfer paper 14. Next, the transfer paper 14 is neutralized by the static eliminator 29, separated from the conveyor belt 23 by the paper separation member 30, sent to the fixing device G, and further stored in the paper discharge tray 37 by the paper discharge device H.

As shown in FIG. 2, the roller position adjustment means 27 includes a latch solenoid 27a, a drive circuit 27b that supplies current to drive the latch solenoid 27a, and one end that engages with the shaft of the deviation correction roller 26. The latch solenoid 27a is made up of a lever 27c whose intermediate portion is rotatably supported on a shaft, and a connecting plate 27f that connects the other end of the lever 27c to the operating rod 27e of the latch solenoid 27a. The drive circuit 27b
can supply currents in different directions to the latch solenoid 27a, and when the currents in different directions are supplied to the latch solenoid 27a, the actuating rod 27e is moved in the direction of arrow e or in the opposite direction. The latch solenoid 27a stops the actuating rod 27e at a predetermined position when no current is supplied in the opposite direction to the previously supplied current.

The bias correction roller 26 and the roller position adjustment means 27 constitute belt position correction means. When the bias correction roller 26 is disposed at the position shown in FIG.
When the bias correction roller 26 is moved in the direction, the correction direction of the conveyor belt 23 is switched to the direction opposite to the direction of the arrow f.

The time sensor 34 includes a light emitting element, such as a light emitting diode 34a that emits infrared light, and a light receiving element, such as a phototransistor 34b. The bias sensor 36 also includes a light emitting element, such as a light emitting diode 36a that emits infrared light.
and a light receiving element such as a phototransistor 36
It consists of b, etc. The detection pieces 33 and 35 are made of aluminum foil.

The positional relationship between the detected piece 33 and the time sensor 34 is such that the toner image is not transferred to the transfer paper 14, that is, after the transfer of the toner image to the preceding transfer paper 14 is completed, to the subsequent transfer paper 14. The detected piece 33 passes through a position where the infrared rays from the light emitting diode 34a of the time sensor 34 are received within the time until the transfer of the toner image is started. Light emitting diode 3 of the time sensor 34
When the infrared rays from 4a are irradiated onto the detection target piece 33, the infrared rays reflected from the infrared rays are incident on the phototransistor 34b.

The positional relationship between the detected piece 35 and the bias sensor 36 is such that only when the conveyor belt 23 is biased to one side, the position where the detected piece 35 receives the infrared rays from the light emitting diode 34a of the time sensor 34 is
The detected piece 35 passes through a position receiving infrared rays from the light emitting diode 36a of the bias sensor 36 in synchronization with the passage of the light emitting diode 36a. When the detection target piece 35 is irradiated with infrared rays from the light emitting diode 36a of the bias sensor 36, the infrared rays reflected from the light emitting diode 36a are transmitted to the phototransistor 36b.
is incident on the Note that when the conveyor belt 23 is biased to the other side, the detection target piece 35 does not pass through the position where the infrared rays from the light emitting diode 36a of the bias sensor 36 are received.

Next, based on the output signals of the time sensor 34 and the bias sensor 36, the bias correction roller 26
The means for controlling the operation of the belt position correcting means comprising the roller position adjusting means 27 and the roller position adjusting means 27 will be explained based on FIG.

In FIG. 3, reference numeral 38 indicates a terminal to which a predetermined positive voltage is applied by the power supply circuit.
Between this terminal 38 and the ground, there is a series connection body of a resistor 34c and a light emitting diode 34a, and a resistor 34d.
A connection body of the phototransistor 34b and a series connection body of the resistor 34e and the resistor 34f are connected in parallel. The connection point g between the resistor 34d and the phototransistor 34b, and the resistor 34e and the resistor 34f
The connection points h are connected to the input terminals of the comparison circuit 34g, respectively. The light emitting diode 34a
The resistor 34d and the phototransistor 3 are connected only when the phototransistor 34b becomes conductive by irradiating the detection target piece 33 with infrared rays, which are reflected from the infrared rays and incident on the phototransistor 34b.
The voltage at the connection point g of 4b is the voltage between the resistors 34e and 34f.
The comparison circuit 34g outputs a higher voltage than the voltage at the connection point h. The light emitting diode 34
a, phototransistor 34b, resistor 34c, 3
4d, 34e, 34f and the comparison circuit 34g constitute a time sensor 34.

Further, a resistor 3 is connected between the terminal 38 and the ground.
A series connection body of 6c and a light emitting diode 36a, a series connection body of a resistor 36d and a phototransistor 36g, and a series connection body of a resistor 36e and a resistor 36f are connected in parallel. The connection point i between the resistor 36d and the phototransistor 36b and the connection point j between the resistor 36e and the resistor 36f are respectively connected to the input terminal of the comparison circuit 36g. Above light emitting diode 3
Only when the phototransistor 36b becomes conductive as the infrared rays from the detection target 35 are irradiated and reflected from the infrared rays and are incident on the phototransistor 36b, the voltage at the connection point i between the resistor 36d and the phototransistor 36b changes to the resistor 36e. resistance 3
The voltage at the connection point j of 6f is lower than that of the comparison circuit 36.
g outputs a high voltage. Above light emitting diode 3
6a, phototransistor 36b, resistor 36c,
36d, 36e, 36f and the comparison circuit 36g constitute a bias sensor 36.

The output terminals of the comparison circuits 34g and 36g are connected to the input terminal of an AND circuit 39, and the output terminal of the AND circuit 39 is connected to the drive circuit 27b of the roller position adjustment means 27. The output terminal of the comparison circuit 34g is connected to the input terminal of the AND circuit 40, and the output terminal of the AND circuit 39 is connected to the AND circuit 40 via an inverter 41.
is connected to the input terminal of This AND circuit 4
The output terminal 0 is connected to the drive circuit 27b.

When the output voltage from the comparison circuit 34g is high and the output voltage from the comparison circuit 36g is high, only the AND circuit 39 provides a high output voltage to the drive circuit 27b. When the output voltage from the comparison circuit 34g is high and the output voltage from the comparison circuit 36g is low, only the AND circuit 40 provides a high output voltage to the drive circuit 27b. The drive circuit 27b supplies current to the latch solenoid 27a when the output voltage of either the AND circuit 39 or 40 is high;
The method of supplying current to 7a differs depending on whether the output voltage of the AND circuit 39 is high or the output voltage of the AND circuit 40 is high.

Therefore, when the time sensor 34 detects the detected piece 33 and the bias sensor 36 detects the detected piece 35, the direction of correction of the deviation of the conveyor belt 23 is determined by the direction in which the time sensor 34 detects the detected piece 35. 33 and when the bias sensor 36 does not detect the detected piece 35
The direction is opposite to the correction direction of the deviation of the conveyor belt 23, and the direction of correction of the deviation of the position of the conveyor belt 23 is the direction opposite to the correction direction of the deviation of the transfer paper 1.
4, the time is switched to a time when no toner image is transferred.

In addition, when the conveyance belt 23 has a connecting part, the detected piece 3 fixed to the conveyance belt 23
By adjusting the relative positional relationship between the connecting portion of the conveying belt 23 and the connecting portion of the conveying belt 23, the transfer paper 14 can be prevented from being placed on the connecting portion of the conveying belt 23. In this way, when the transfer paper 14 is not placed on the connecting portion of the conveyor belt 23, the conveyor belt 23
Since the toner image is not transferred to the transfer paper 14 at the connection portion 3, it is possible to prevent the connection portion of the conveyor belt 23 from having an adverse effect on the transfer of the toner image to the transfer paper 14.

A paper sensor 4 is located between the registration roller 20 and the photoreceptor 1 near the transport path of the transfer paper 14.
2 is placed. The paper sensor 42 includes a light emitting element, such as a light emitting diode 42a that emits infrared light, and a light receiving element, such as a phototransistor 42b. This paper sensor 42 is
The leading edge of the transfer paper 14 conveyed by the conveyance belt 23 is detected.

Next, a specific embodiment of the paper sensor 42 and means for controlling the operation of the exposure device B based on the output signal of the paper sensor 42 will be described with reference to FIG.

In FIG. 4, reference numeral 43 indicates a terminal to which a predetermined positive voltage is applied by the power supply circuit.
Between this terminal 43 and the ground, there is a series connection body of a resistor 42c and a light emitting diode 42a, and a resistor 42d.
A connection body of the phototransistor 42b and a series connection body of the resistor 42e and the resistor 42f are connected in parallel. The connection point k between the resistor 42d and the phototransistor 42b, and the resistor 42e and the resistor 42
Connection points l with f are respectively connected to input terminals of a comparison circuit 42g.

The conveyor belt 23 has a light emitting diode 42a
It is made of a dielectric material that has a very high transmittance to the infrared rays it radiates. The transmittance of the infrared rays emitted by the light emitting diode 42a to the transfer paper 14 is extremely low. Therefore, when the transfer paper 14 is not in a position to receive the infrared rays emitted from the light emitting diode 42a of the paper sensor 42, the infrared rays received by the phototransistor 42b are very weak, and the infrared rays emitted from the light emitting diode 42a of the paper sensor 42 are very weak. When the transfer paper 14 is located at a position where it receives infrared rays, the infrared rays received by the phototransistor 42b are strong. Only when the infrared rays emitted from the light emitting diode 42a are reflected by the transfer paper 14 and incident on the phototransistor 42b, the phototransistor 42b becomes conductive, and the voltage at the connection point k between the resistor 42d and the phototransistor 42b changes to the resistor 42e. The voltage becomes lower than the voltage at the connection point l of the resistor 42f, and the comparator circuit 42g outputs a high voltage. The output terminal of the comparison circuit 42g is connected to a Schmitt trigger circuit 42h. This Schmitt trigger circuit 42h outputs a high voltage for a predetermined period of time when the output voltage of the comparator circuit 42g suddenly increases. The light emitting diode 42a and the phototransistor 4
2b, resistors 42c, 42d, 42e, 42f, comparison circuit 42g and Schmitt trigger circuit 42h
constitutes a paper sensor 42.

The output terminal of the Schmitt trigger circuit 42h is connected to a drive circuit 44 that supplies current to operate a drive device that moves the scanning optical system members including the illumination lamp 4 and the first mirror 6 of the exposure apparatus B. . When this drive circuit 44 receives a high output voltage from the Schmitt trigger circuit 42h, it is closed for a predetermined period of time to operate a drive device that moves the scanning optical system members.

Therefore, the paper sensor 42 detects the transfer paper 14.
When the leading edge of the exposure device B is detected, the scanning optical system member of the exposure device B starts to move, and the exposure device B starts forming an image on the photoreceptor 1. The distance between the paper sensor 42 and the transfer position m of the toner image on the photoconductor 1, and the distance between the start position n of image formation by the exposure device B on the photoconductor 1 and the transfer position m of the toner image on the photoconductor 1. are adjusted to have a predetermined relationship, the transfer paper 1 of the toner image to be transferred
The position at 4 becomes constant.

Effects According to the present invention, even if the conveyance belt that conveys the transfer paper deviates from its normal position, the time during which the toner image is not transferred to the transfer paper, that is, the time during which the transfer of the toner image onto the transfer paper is not affected. The belt position correction means can correct the transfer position of the toner image in the width direction of the transfer paper relative to the transfer paper to an appropriate position, and also adjust the distance from the exposure position of the photoconductor to the transfer position and the registration. Even with configurations in which the distance from the roller to the transfer position is different, the best copy can be obtained by keeping the transfer position of the toner image relative to the transfer paper constant in the direction in which the transfer paper advances.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the outline of the electronic copying machine of the present invention, Fig. 2 is a partially cutaway perspective view showing the transfer paper conveyance device of the above electronic copying machine, and Fig. 3 is a belt position of the above transfer paper conveyance device. FIG. 4 is an electric circuit diagram showing a means for controlling the operation of the correction means, and FIG. 4 is an electric circuit diagram showing a means for controlling the operation of the exposure device of the electronic copying machine of the present invention. B... Exposure device, D... Transfer device, F... Transfer paper conveyance device, 1... Photoreceptor, 20... Registration roller, 42... Paper sensor.

Claims (1)

[Claims] 1. In an electronic copying machine that feeds transfer paper between a photoreceptor and a transfer device by a pair of registration rollers and a conveyor belt, detecting the time during which a toner image is not transferred to the transfer paper. A time sensor and a deviation sensor that detects the deviation of the conveyor belt are arranged, and when the time sensor detects the time during which the toner image is not transferred to the transfer paper, and the deviation sensor detects the deviation of the belt, It has a belt position correction means for correcting the deviation of the conveyance belt, and a paper sensor for detecting the leading edge of the transfer paper is disposed near the conveyance path of the transfer paper between the photoreceptor and the registration roller, and the paper sensor detects the leading edge of the transfer paper. An electronic copying machine characterized in that an exposure device starts forming an image on a photoconductor when a sensor detects the leading edge of a transfer paper.