JPH0760275B2 - Electronic copying machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry type electronic copying apparatus, and more particularly to improvement of a conveyance path for conveying transfer paper.

2. Description of the Related Art An electrostatic latent image carrier, for example, an image forming means for forming a toner image on a photosensitive member with powder toner, and a transfer paper for transferring a transfer paper to the electrostatic latent image carrier to obtain a toner image on the transfer paper. Means, a fixing means for fixing the transfer toner image to the transfer paper on a member such as a heated roll, and a paper feeding means for supplying the transfer paper to the image forming means, which are the main constituent means. In an electronic copying apparatus in which an electrostatic latent image formed on a latent image holding member is visualized, a transfer paper is transferred to the electrostatic latent image holding member to obtain a transferred toner image and then heated. It is contained therein because it is heated by the fixing means. Moisture evaporates, leading to a decrease in water content.

Generally, the paper used as the transfer paper contains about 4% to 8% of water under the moisture measurement conditions of JISP 8111, and retains the desired characteristics of the transfer paper. However, as described above, when the transfer paper passes through the heat fixing means which is usually heated to about 160 to 190 ° C., the temperature of the transfer paper causes the water to evaporate, and the transfer water content is about 2% to 4%. Is reduced. As a result, the transfer paper is physically distorted and the transfer paper is deformed due to the shrinkage of the wood fibers that make up the transfer paper.
It is a general trend that the electrical resistance of transfer paper increases.
Recently, in electronic copying machines, in order to save paper resources,
Copying is performed on both sides of a transfer paper, or two times or three times are performed on one side for colorization of a copy, and as a result, when performing double-sided copying or multiple times on one side. During copying, the electric resistance increases and the deformed transfer paper is fed to the image forming means of the electronic copying apparatus. In such paper feeding, since the deformed transfer paper is supplied to the transfer paper conveyance path in the image forming means of the electronic copying apparatus, the transfer paper comes into contact with a part of the conveyance path, and the paper jam occurs. Or the paper passes through the heat fixing means again in a deformed state, and paper wrinkles are likely to occur. Furthermore, since the electric resistance of the transfer paper is increased, it is difficult for the charges on the transfer paper to escape, and as a result, the transfer papers are brought into close contact with each other due to electrostatic attraction, causing double feeding, or due to electrostatic effects The image is disturbed.

On the other hand, the usage environment of the electronic copying machine is not used often in a place where the atmosphere is adjusted recently. For personal use, when the humidity in the usage environment reaches 85 to 90%. Is also occurring. In such an atmosphere, the transfer paper absorbs moisture and its moisture content is 10
It is several percent, and as a result, paper jams in the transfer conveyance path due to the decrease in the rigidity of the transfer paper and transfer failure due to the decrease in resistance value are caused.

In order to solve the above problems, for example, Japanese Utility Model Publication No. 58-39464 and Japanese Patent Application Laid-Open No. 58-125074 attempt to dehumidify the transfer paper, and some improvement examples of the above problems are recognized. It is hard to say that it is enough to correct the characteristics. Further, the inventors of the present application added a humidifying means for replenishing the moisture content to the transfer paper which has passed through the low-adhesion means, and tried to improve the above-mentioned problem associated with the reduction of the moisture content. When the environment is highly humid, the transfer paper that is initially fed has a high water content, so if the transfer paper that has passed through the fixing means is humidified by the humidifying means, the water content becomes excessive.
In many cases, a transfer failure occurs due to a decrease in the transfer paper resistance value, and a paper jam, a paper wrinkle or the like occurs due to a decrease in the rigidity of the transfer paper, resulting in an adverse effect.

Problems to be Solved by the Invention In such a conventional water content correction means for a transfer paper, the transfer paper whose water content is not regulated is fed to the image forming means or the transfer means. Resistance values,
Stable transfer because the rigidity etc. varies depending on the environment in which the copying machine is used,
It was difficult to convey the paper.

The present invention has been made in consideration of the above point, and corrects the moisture content so that the resistance value of the transfer paper becomes an appropriate value, thereby correcting the deformation of the transfer paper, and thus the transfer failure and the paper jam. The purpose is to prevent the occurrence of wrinkles and paper wrinkles.

Means for Solving the Problems In order to solve the above problems, the present invention performs dehumidification and humidification of a transfer sheet in conjunction with a means for measuring the resistance value of the transfer sheet in the sheet feeding means and the resistance value. By adding a means, a proper amount of water is contained in the transfer paper to correct the characteristics of the transfer paper and the paper is fed to the next image forming means.

Action The present invention is configured to correct the water content of the transfer paper, and to correct the deformation and electric resistance of the transfer paper, by the water content correction means controlled for the transfer paper according to the above-described configuration. The rate of occurrence of transfer defects, paper jams, paper wrinkles, and double feeding during normal copying, double-sided copying, or copying multiple times on one side is significantly reduced.

Embodiment An embodiment of the electronic copying apparatus of the present invention will be described below with reference to the drawings.

FIG. 1 is an internal structure diagram showing an example of an electronic copying apparatus according to the present invention. In the figure, reference numeral 1 denotes a copying apparatus main body, and a tourist drum 2 is provided at a substantially central portion thereof so as to be rotationally driven in an arrow direction. Around the drum 2,
Charging charger 3, developing device 4, transfer charger 5,
The separation charge-eliminating charger 6 and the cleaning device 7 are sequentially arranged in the rotation direction of the drum 2 indicated by the arrow, and constitute a main image forming unit and a transfer unit of the image forming unit. More specifically, in this image forming unit, after cleaning the tourist drum 2 with the cleaning device 7, the charging charger 3 charges the charged drum surface, and the charged surface is passed through the scanning optical system 9 to mount the original on the upper surface of the main body 1. An image forming means for exposing an image of a document placed on the placing glass 8 to form an electrostatic latent image, and developing the electrostatic latent image with a toner by the developing device 4, and a toner image after the development are referred to as a toner image. On the other hand, the main part is constituted by the transfer means that transfers the transfer charger 5 onto the transfer paper that is sent in synchronization. Further, the transfer paper on which the toner has been transferred is separated from the surface of the drum 2 by the separation power charger 6. The surface of the drum 2 from which the transfer paper is separated returns to the initial state after the cleaning device 7 scrapes off the residual toner.

An original cover 10 is attached to the main body 1 so as to be opened and closed with respect to the original placing glass 8. Reference numeral 11 is an imaging lens of the scanning optical system.

On the left side of the image forming section, a sheet feeding means for feeding the transfer sheet to the transfer means, and on the right side of the image forming section, the drum 2 after the transfer.
A transfer path 12 for carrying the transfer paper separated from the fixing paper, a fixing means 13 composed of a member such as a heating roll for fixing the transfer toner image on the transfer paper, and a paper discharge portion for discharging the transfer paper passing through the fixing means 13. They are arranged to form a normal copying machine. The paper feeding means includes a paper feeding cassette 14 for accommodating transfer papers of different size copying papers, and a paper feeding cassette 15 which are vertically mounted in a state of being stuck on one surface of the copying apparatus main body 1, and a paper feeding roller 16 , 17 and the temporary stop adjustment roller 28 are selectively driven to transfer the transfer paper from one of the paper feed cassettes 14 and 15 or the transport path 19 to the first timing roller.
39, sent out to the second timing roller 20, and sent to the transfer means under the photosensitive drum 2 in synchronism with the movement of the toner image on the drum 2.

Transfer paper discharged from the fixing unit 13 is supplied to the paper discharge unit.
Guide claws that feed the output tray 22 through the output roller 21
23 and a feed roller 24 are provided. In the case of normal one-sided copying, transfer papers are stacked and stored in the paper discharge tray 22 by the operation of these paper discharge units.

In the above copying machine, for the transfer paper after one-sided copying,
A single-sided copy assisting device that enables multiple copies for copying again on the copied side, and the transfer paper after the single-sided copy is sent back to the image forming unit in a reverse state and double-sided copy for copying on the back side. Auxiliary means are provided.

The selection of these two auxiliary means is selected by the operation of the two guide claws of the guide claw 23 and the guide claw 25.
In the illustrated state of the guide claw 23 of FIG. 1, these two auxiliary means are in the operating state, and further, the guide claw 25
Is in a state where the double-sided copy assisting means operates. The one-sided copy assisting means is formed by rotating the guide claw 25 in the clockwise direction, and the transfer paper which has passed through the fixing means 13 is guided by the guide claw 23 and the guide claw 25 and sent to the transport path 19. It is conveyed by the feed roll 26 and the conveyance belt 27, and is put in a waiting state by the temporary stop adjusting roller 28 for the next copy. Then, it is sent to the first timing roller 39 in accordance with the operation of the image forming unit. The two-sided copying assistance means is the first
The transfer paper which is in the operating state in the state of the guide claw 23 and the guide claw 25 shown in the drawing and which has passed through the fixing unit 13 is
It is stabilized by the guide claw 23 and the guide claw 25, is once sent to the switchback unit 30 by the feed roll 29, and then immediately sent back to the conveyor belt 27 by the operation of the feed roll 29, and then for back side copying. Then, the suspension adjusting roller 28 is put in a waiting state. Here, the transfer paper which has been subjected to the single-sided copying is stacked on the conveyor belt 27 in a state in which the leading end of the transfer paper is displaced backward by several centimeters, as shown in FIG.

The above is an example of a copying apparatus used under the present invention. In the copying apparatus according to the present invention, further,
The configuration described below is added. That is, in FIG. 1, the transfer sheet that has passed through the paper feed roller 16 or 17 is guided to the transfer means below the photosensitive drum 2 and is guided by the guide plate.
It is guided along 18-1 and passes through a resistance detector 32 for measuring the electric resistance value of the transfer paper. Here, the transfer of the transfer paper is temporarily stopped by the first timing roller 39, and
When the electrode plate 34 shown in the figure is brought into contact with the back surface of the transfer paper 43, the transfer paper 43
Measure the resistance of. As shown in FIG. 4, the electrode plate 34 is provided with three electrodes concentrically, and insulating plates (Teflon plates) 35 are inserted between the electrodes and are alternately arranged. The electrode plate 34 is connected to the AC current generator shown in FIG. 5 and a logarithmic amplifier described later to measure the surface resistance value of the transfer paper 43. The opposite side of the transfer paper against which the electrode plate abuts in the resistance detection section is a silicon rubber plate protruding from the hole provided in the guide plate.
It is held down by 36 to improve the adhesion between the electrode plate and transfer paper. Generally, the relationship between the water content of the transfer paper and the resistance value changes exponentially with respect to the water content, and its approximate value varies greatly depending on the water content as shown in FIG. is there. Therefore, a logarithmic amplifier is added to the resistance detection unit 32 to detect the voltage between the electrode plates which greatly changes, and the content of water content is corrected by comparing the magnitude of the resistance value of the transfer paper with a desired resistance value. To send the control signal to. That is, when the resistance value of the transfer paper is larger than the value when it is left under the moisture measurement condition of JIS P 8111, the humidifying pipe 33 in the moisture content correction means is activated to increase the moisture content, When the resistance value is small, the heat roll 37 is operated to reduce the water content, and when the transfer paper passes through the water content correction means from the resistance detection unit 32, the water content of the transfer paper is reduced. Is corrected to an appropriate value. The transfer sheet that has passed through the resistance detection unit 32 and the water content correction unit passes through the second timing roller 20 and is guided to the next step. still,
The resistance detection unit 32, the humidification pipe 33, and the heat roll 37 are close to each other, and the humidification pipe 33 is used to prevent the measurement fluctuation of the resistance detection unit 32 due to the moisture generated from the humidification pipe 33 and the heat roll 37.
The heat roll 37 is covered with a box 38, and a first timing roller 39 is provided at a portion where the transfer paper is projected to prevent the high humidity air from diffusing to the resistance detection unit 32. A hole is provided on one side surface of the box 38, and high humidity air generated when the humidifying pipe 38 and the heat roll 37 are operated is discharged to the outside of the machine by the fan 40. FIG. 7 is an enlarged view of a main part of the water content correction means. In FIG. 7, one side of the heat roll 37 is made of Teflon resin.
A rod-shaped halogen lamp is inserted in the center of a 1 mm thick aluminum pipe with a diameter of 25 mm and a surface covered with a thickness of about 4 mm. On the other hand, a silicon rubber with a rubber hardness of 20 ° is placed in the core aluminum lot. It is composed of backup rolls having a diameter of 25 mm and coated with a thickness of 5 mm, and two pairs of these rolls are arranged upside down as shown in the figure. The linear pressure of each is about 100 g per cm of the nip portion, which is an extremely low value as compared with the heat roll type fixing means which normally maintains a similar structure. Two halogen lamps each with a power consumption of 300w are used, and the halogen lamp is turned on by the signal from the logarithmic amplifier and is smaller than the resistance value when it is notified to the moisture measurement condition of JIS P 8111. The aluminum pipe is heated to dehumidify the transfer paper. The electric power applied to the halogen lamp changes the normal commercial current by the phase control of the thyristor by the signal of the logarithmic amplifier to control the dehumidification amount from the transfer paper. Figure 8 shows
The humidifying pipe 33 is shown. FIG. 9 shows a humidifying means including the humidifying pipe 33. In these figures, a plurality of small holes 41 are provided on the surface of the humidifying tube 33 through which the transfer paper passes.
The humidifying pipes 33 provided with the small holes 41 are arranged side by side so that the surfaces on which the small holes 41 are provided face each other, and a guide plate 18-3 is attached in the middle thereof to The guide plate in the portion where the 41 is provided has a mesh shape so as to allow ventilation. A pipe 44 is connected to the humidification pipe 33 so that the humidified air is sent from the humidification container 43 in which the humidity adjusting liquid 42 is stored. A pipe 46 is connected to the humidifying container 43 so that air can be sent from the pump 45. The electric motor that drives the pump 45 is an electric motor whose rotation speed is variable, and the rotation speed changes in conjunction with the signal from the logarithmic amplifier. Transfer paper JIS
P8111 starts to rotate when it is larger than the resistance value when left in the moisture measurement condition, and as the value increases,
The rotation speed increases, and the amount of air fed from the pump 45 increases.

Since the water content correction means is configured as described above, it takes about 15 to 20 seconds from the detection of the resistance value of the transfer paper to the normal operation state. The first timing roller 39 puts it in a standby state at the position of the resistance detector. However, when copying continuously, the fluctuation range of the resistance value of the first transfer paper and the resistance value of the second and subsequent transfer papers is small. Each timing roller is controlled so that the transfer paper is conveyed with the waiting time in the detection unit set to zero.

The electronic copying apparatus according to the present invention has the above-mentioned configuration. The following experiment was conducted in this copying apparatus to confirm the effects of the present invention. That is, the copying machine is capable of passing the A4 size transfer paper in the lateral feeding state through the transfer means, the fixing means, and the paper feeding means.
Double-sided copying was performed in an environment of 30 ° C humidity 80% and temperature 30 ° C humidity 30 ° C. Moisture content correction means, transfer paper surface resistance
Humidified air with humidity of 90% at 10 ¹⁵ Ω is 151 / min, and at 10 ¹² Ω is 71 / min.
Min., 10 ¹¹ Ω, the contact value was set so as to be delivered to the humidifying pipe 33 at a rate of 01 / min. When it became 10 ¹⁰ Ω, a voltage was applied to the heat roll 37. The applied power at this time was 150w, and 300w was applied at 10 ⁹ Ω. Next JIS
In the moisture measurement conditions of P 8111, the moisture content is 7%, the direction of the fibers is perpendicular to the longitudinal direction of the transfer paper, and the basis weight is 62 g.
A4 size transfer paper with a surface resistance of 10 ¹¹ Ω was fed laterally and 30 sheets were continuously copied on one side. At this time, the transfer paper after one-sided copying was stacked on the conveyor belt 27 by the guide claw 23 and the guide claw 25 so that the back surface was copied. Next, a continuous operation of copying 30 sheets was performed on the back surface of the transfer paper, and the copied transfer papers were stacked on the paper discharge tray 22 by the guide of the guide claws 23. This operation was repeated 20 times to make a total of 600 double-sided copies. At this time, for comparison, first, copying was performed without operating the water content correction means. As a result, 30 ℃
In the environment of 30%, due to the deformation of the transfer paper after one-sided copying,
15 paper jams occurred near the timing roller 20 or the transfer charger 5. Also, the conveyor belt
When the transfer paper was conveyed to the timing roller 20 from above 27, a plurality of transfer papers were simultaneously sent to the image forming section, that is, so-called double-feeding occurred five times. Further, some of the transfer papers stacked on the paper discharge tray and subjected to double-sided copying had wrinkles in the fiber direction, and the number was 191. The moisture content of the transfer paper in this environment was 6.42% before copying and 3.10% after double-sided copying. On the other hand, under the environment of 30 ℃ 80%, each paper jam 2
The number of paper wrinkles was 0, the number of times of double feeding was 4 times, and the humidity was remarkably less than in the environment of 30% humidity. However, in the copied image after one-sided copying, almost all the copied products had a thin portion of the image which was not normally transferred. The moisture content of the transfer paper in this environment was 11.5% before the entire copying and 5.73% after the double-sided copying. Next, the water content correction means was operated to control the water content of the transfer paper. And
A copying experiment similar to the above was performed. As a result, the paper jam in the 80% environment is 0 times, the double feeding is 0 times, and the paper wrinkle is 0 sheets, which is compared with the case where the moisture content correction means is not operated.
Paper jams and double feeding did not occur at all, and no defects such as defective transfer were observed on the image.
Even under the environment of 30% humidity, paper jam was once, double feeding was 0 times, and paper wrinkles was 0 times. At this time, in the original JIS P8111 moisture measurement condition, the transfer paper with a moisture content of 7% had a moisture content of 11.4% in an environment of 80%, but it decreased to 8.20% by passing through the heat roll 37. did. On the other hand, the moisture content was 6.50% under the environment of 30% humidity, but 8.30% by passing between the humidifying pipes 33.
Increased. In addition, here, the moisture content of the transfer paper was measured by the microwave paper moisture meter MX-2000 (Infrared Engineering).
Manufactured) was used.

EFFECTS OF THE INVENTION According to the present invention, it is possible to greatly reduce the troubles caused by the transfer paper, such as paper jam, double feeding, paper wrinkle, and transfer failure, which are caused by the normal electrophotographic copying means. The reason for this is that the water content of the transfer paper changes greatly depending on the environment in which the copying machine is installed, and the paper is deformed due to the forced removal of the water content of the transfer paper by the heat fixing means, or Before the paper is fed to the copying means, the change in the resistance value of the paper is corrected to the proper value of the water content based on the change in the resistance value to show the effect by adjusting the physical characteristics of the paper. It is of great industrial value.

[Brief description of drawings]

FIG. 1 is an internal structure diagram showing an example of an electronic copying apparatus according to the present invention, FIG. 2 is an enlarged view of a conveyor belt portion, FIG. 3 is an enlarged view of a main portion of a resistance detecting portion, and FIG. 4 is an electrode plate. Sectional view, FIG. 5 is a block diagram of the circuit of the resistance detection unit, FIG. 6 is a graph showing the relationship between the moisture content of the transfer paper and the resistance value, and FIG. 7 is an enlarged view of the main parts of the guide plate and the humidifying tube. FIG. 8 is an enlarged view of the humidifying pipe, and FIG. 9 is a conceptual diagram showing a humidifying means including the humidifying pipe. 2 ... Photosensitive drum, 5 ... Transfer charger, 12, 19
…… Paper transport path, 13 …… Heating and fixing unit, 23,25 …… Guide claws, 30 …… Switchback section, 32 …… Resistance detection section, 33 ……
… Humidification tube, 37… Heat roll.

Claims (1)

[Claims] 1. An image forming unit for forming a toner image on an electrostatic latent image holding member, and a transfer unit for transferring a transfer paper to the electrostatic latent image holding member to obtain a toner image on the transfer paper. An electronic copying apparatus comprising at least a fixing means for fixing a transfer toner image to a transfer sheet by a heated member, and a sheet feeding means for conveying the transfer sheet to the creating means, On the other hand, an electronic copying apparatus is provided with a transfer paper resistance value measuring means and a transfer paper moisture content correcting means for humidifying and dehumidifying the transfer paper in association with the resistance value obtained by the measuring means.