JPH0934281A - Electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic device capable of restraining an influence of the swelling of a booklet binding part, preventing toner from scattering, and accurately printing characteristics of characters, frames, etc., on the specified position of the booklet. SOLUTION: The device is provided with a transfer means 4 for transferring a toner image formed on a photoreceptor drum 22 to the carried booklet 20, a means for detecting a current which flows in the booklet 20 at time of transfer, means 1, 2 and 3 for controlling a transfer pressure and a transfer voltage, means 9 and 10 for fixing the transferred toner image, means 6 and 13 for detecting the thickness of the booklet, and the device is provided with a calculating part for calculating a timing that the booklet comes into contact with the photoreceptor drum and the transfer means and a pattern of a pressure applied by the transfer means to the booklet based on the positions of the sensors 6 and 13 and the carrying velocity pattern of the booklet, and also, the fixing means 9 is provided with pressure control means 7 and 8, and the device is suitable for a printer capable of printing on a cut paper and many pieces of paper >=0.2mm thickness. The toner image on the photoreceptor drum can be accurately transferred to the thick cut paper and the booklet such as a passbook, etc., without being affected by the binding part and the thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus, and more particularly to an electrophotographic apparatus suitable for an electrophotographic printer capable of printing on booklets such as passbooks.

[0002]

2. Description of the Related Art A conventional electrophotographic apparatus is disclosed in Japanese Patent Laid-Open No. 2-30.
As described in Japanese Patent No. 0774, paying attention to the change in transfer current with respect to the change in temperature and humidity of a medium such as paper,
The optimum transfer voltage is calculated from the transfer current and controlled.

[0003]

SUMMARY OF THE INVENTION In the above-mentioned prior art, a printing object is a cut sheet or a booklet having a thickness 20 times or more as compared with a so-called OHP sheet (transparent film used for an overhead projector). No consideration is given to printing. That is, when printing is performed on a designated portion of the page of the booklet, the thickness of the booklet at the printed portion changes. In particular, when printing is performed with the booklet or the like closed, a pressure of several tens of times or more is applied to the booklet or the like sandwiched by the transfer roller and the photosensitive drum as compared with the related art. In addition, in the vicinity of the binding portion in the center of the booklet, etc., there are often bulges at the beginning, so in order to remove this bulge,
It is necessary to apply pressure.

Therefore, there is an optimum range for the pressure applied to a medium such as a booklet held between the transfer roller and the photosensitive drum. If the pressure is less than this optimum range, the bulge in the vicinity of the binding portion cannot be removed, and the printed characters are deformed. Further, when a pressure exceeding this optimum range is applied, a hollow phenomenon occurs in which toner of printed characters is scattered.

The present invention has been made on the basis of the above-mentioned matters, and in particular, it suppresses the influence of the bulge generated at the binding portion of a booklet such as a passbook, prevents the toner from scattering, and sets the predetermined booklet. An object of the present invention is to provide an electrophotographic apparatus capable of accurately printing features such as characters and frames at positions.

[0006]

The above object of the present invention is to transfer a toner image on a toner image carrier such as a photosensitive drum onto a predetermined page of a recording medium such as a booklet having a plurality of pages by a transfer roller or the like. In an electrophotographic apparatus for printing by means, a thickness detecting means for detecting the thickness of the recording medium, and a calculating means for calculating the pressing force of the transfer means on the recording medium from the information detected by the thickness detecting means. And a control unit that controls the pressing force based on the calculation result.

In order to achieve the above object, the present invention detects a transfer means for transferring a toner image on a toner image carrier onto a recording medium which conveys the toner image and a current flowing in the recording medium at the time of the transfer. Transfer voltage control means for controlling the transfer voltage, transfer pressure control means for detecting the thickness of the recording medium at the time of the transfer and controlling the transfer pressure applied to the recording medium, and fixing the toner image transferred on the recording medium. And a fixing unit for controlling the recording medium thickness detecting unit and the transport speed pattern of the recording medium, the timing at which the recording medium comes into contact with the toner image carrier and the transfer unit, and the transfer unit. It is characterized in that it has a calculation unit for calculating a pressure pattern applied to the recording medium.

[0008]

According to the above construction, the appropriate pressing force of the transfer means can be calculated and controlled from the thickness of the recording medium such as a booklet, so that the proper transfer can be performed even for a booklet having a bulge in the binding portion. The toner image can be accurately transferred by the pressure. Further, by detecting the current flowing in the recording medium at the time of transfer and controlling the transfer voltage, it is possible to prevent variations in transfer accuracy due to the water content of the recording medium and the like. Therefore, compared to cut paper or OHP paper having a thickness of about 0.1 mm, cut paper or booklets having a thickness several times to several tens of times or more are not affected by the binding portion or the thickness. It is possible to accurately transfer and fix the toner image created by the toner image generating means such as the photosensitive drum.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a transfer mechanism diagram of the electrophotographic apparatus of the present invention. The first guide, the paper pan 12, the second guide, the paper guide 11, and the paper guide 1.
5 forms a conveyance path for conveying the booklet 20 which is a recording medium from right to left in the drawing. In this transport path,
Conveying rollers 9, 10, 14, and 18 are provided as conveying means.

Of these rollers, the conveying rollers 9 and 18 are supported by elastic members 8 and 17 such as springs, respectively, in order to cope with a change in thickness from a booklet binding a plurality of sheets to a cut sheet, and are elastic. The members 8 and 17 are supported by drive sources 7 and 16 such as solenoids, and the conveyance rollers 9 and 18 are provided.
However, the force that pushes the booklet 20 is controlled.

In this embodiment, these transport rollers 9, 1 are used.
0, 14, 18 and the transfer roller 4 are drive rollers. If the booklet 20 is thin, the drive sources 7, 16
Does not have to be. Further, the transport rollers 9 and 18 may be driven rollers. Further, the transport roller 9
Is also a fixing roller for making a toner image attached to the booklet 20 which is a recording medium by an electric attraction force or the like into a permanent image. Therefore, the fixing roller 9 has a heat source, a temperature sensor, etc. inside.

The thickness detection sensors 6 and 13 detect the thickness of the booklet that has entered the printing section. Based on the thickness data from the sensors 6 and 13, the force for pushing the transfer roller 4 toward the photosensitive drum 22, the voltage from the variable high voltage power source 1 applied to the transfer roller 4, and the pushing force and the voltage. Calculate the timing of adding. Although the description of the fixing unit is omitted this time, the toner image transferred onto the recording medium such as the booklet 20 becomes a permanent image due to heat and pressure. The variable high-voltage power supply 1 has a ground 5
Is connected.

The transfer roller 4 is composed of a conductive rubber and a core metal, and is loaded with a high voltage by the variable high voltage power source 1. Further, the force applied by the transfer roller 4 to the photosensitive drum 22 can be controlled by the spring 3, the solenoid 2, and the like.

A charging device 23, an exposing device 24, a developing device 25 and the like are provided close to the photosensitive drum 22, and the toner 26 is transferred from the developing device 25 to the photosensitive drum 22 by electrostatic force.
Form a toner image. The intervals between the transport roller 10 and the transfer roller 4 and between the transport roller 14 and the transfer roller 4 are at least shorter than the length in the transport direction when the booklet 20 is closed.

The operation of the electrophotographic apparatus according to the present invention will be described with reference to FIGS. 2 to 6. As shown in FIG. 2, the booklet 20
Is conveyed in the direction A by the conveying rollers 14 and 18 on the paper pan 12, and the sensor 6 detects the booklet 20. The booklet 20 stops at a predetermined position surrounded by the transfer roller 4 and the photosensitive drum 22 which is a transfer portion. On this occasion,
The force applied to the transfer roller 4 by the solenoid 2 as a drive source is weakened so that the transfer roller 4 becomes a resistance against the insertion of the booklet 20 so that the pages on the surface of the booklet 20 do not buckle or bend. .

As shown in FIG. 3, in the photosensitive drum 22,
By rotating in the rotation direction B, a charging process on the photosensitive drum by the charging device 23, an electrostatic latent image forming process by the exposing device 24, and a toner image forming process on the photosensitive drum 22 by the developing device 25 are performed. In addition, the booklet 20
The speed of movement to the left side (direction A in FIG. 2) in the figure and the photosensitive drum 2
The speeds at which 2 moves in the B direction are consistent.

Next, as shown in FIG.
When the photosensitive drum 22 is conveyed in the direction and comes into contact with the photosensitive drum 22, a voltage calculated from the thickness information detected by the thickness detection sensor 6 is applied to the transfer roller 4 from the variable high voltage power source 1. Further, a predetermined pressure is applied from the transfer roller 4 to the booklet 20 by the solenoid 2 giving an optimum amount of deformation to the spring 3 so that the optimum transfer pressure calculated from the thickness information is applied to the booklet 20.

The reason why the pressing force, which is the force for the transfer roller to press the recording medium such as a booklet toward the photosensitive drum, is changed by a driving source such as a solenoid as shown in FIG. 7 is EPDM or silicon. In the transfer roller composed of the foamed conductive rubber or the like, the deformation amount t ₁ ,
With respect to t ₂ , t _3, etc., the reaction force increases in a quadratic curve rather than linearly. Therefore, in recording media such as booklets,
This is because the thickness is several tens of times greater than that of cut paper, and therefore the pressing force applied to at least the booklet is several tens of times greater.

Further, as shown in FIG. 8, the pressure between the photosensitive drum and the recording medium such as a booklet is approximately 200 g / cm.
^{When the number is 2} or more, a failure commonly referred to as a hollow hole occurs. For example, if the contact area at the time of transfer is set to 21.7 mm ² , the hollow between the photosensitive drum and the transfer roller will occur if a force exceeding 43.4 g is applied.

The problem called the hollow portion is that a part of the toner in the toner image formed on the photosensitive drum is
Since it is not transferred to a recording medium such as a booklet, it means that there is no toner in the portion where the toner should exist on the recording medium and the recording medium is directly exposed on the surface. Toner: Says when absent.

When the transfer roller is fixed and the transfer roller is deformed by the thickness of the paper, the cut paper (thickness: 0.
With a thickness of about 1 mm), the transfer pressure generated by the reaction force caused by the deformation of the rubber portion of the transfer roller is a pressure P ₁ that is smaller than the transfer pressure that causes hollowing. However, 0.2mm
With the above thickness of the cut paper or booklet, the transfer pressure of P ₂ or P ₃ is generated. As a result, hollow defects occur, and it is necessary to control the transfer pressure.

As shown in FIG. 5, when it is necessary to transfer the toner image also near the binding portion of the booklet 20, the transfer roller 4 needs to be pressed with a force larger than the pressing force at the time of transfer described above. is there. This is because an air layer or the like is formed between pages in the vicinity of the binding portion of the booklet 20 and a bulge is likely to occur locally. Therefore, in order to suppress this bulge, it is necessary to press with a pressure larger than the normal optimum pressing force. However, if it is possible to remove the bulge near the binding portion of the booklet 20 before entering the transfer portion surrounded by the photosensitive drum 22 and the transfer roller 4, it is not necessary to change the pressing force.

As shown in FIG. 6, the booklet 20 is discharged from the transfer section by the conveying rollers 9, 10 and the like, whereby the operation of transferring the toner image on the photosensitive drum 22 to the recording medium 20 such as the booklet ends. The fixing roller 9 and the driving roller 10 apply heat and pressure to the recording medium 20 to make the toner image on the recording medium 20 permanent.

Next, a booklet printer which is another embodiment of the present invention will be described with reference to FIG. As shown in the figure, the booklet printer 200 has at least the insertion port 100,
Transport rollers 102, 103, 106, 107, 122,
124, 126, conveying path 160, magnetic information reading unit 1
04, magnetic information recognition unit 130, image reading unit 10
5, image information recognition unit 131, drive motor 108, photosensitive drum 111, charging device 115, exposure device 114, laser or LED 113, developing device 112, conveyance fixing roller 1
25, 127, a transfer roller 117, a spring 119, a drive source 118, paper guides 109, 132, a data interface 134, a calculation unit 135, a control unit 136, sensors 101, 110, 121 and the like.

The booklet 133 inserted in the direction A from the insertion slot 100 passes through the sensor 101, and the magnetic information reading unit 104 reads or writes the information written in the magnetic stripe of the booklet 133 to obtain the magnetic information. Recognition unit 1
The information is recognized at 30, and then the image information reading unit 1
At 05, print information such as how many pages are present on the front page and up to which line has been printed are read, and the image information recognition unit 131 recognizes the image information.

Based on the above two pieces of information, the arithmetic unit 135 determines whether or not to print, and when it is determined to print, the control unit 136 sends a print command and print data. Further, the thickness of the booklet 133 is detected by the sensor 110,
The detection data is sent to the interface unit 134. From the detection data, the calculation unit 135 calculates the optimum pressing force of the transfer roller 117 and the initial deformation amount of the spring 119 necessary to generate the pressing force, and based on the calculation result, the movement amount of the drive source 118, etc. And sends data such as the pressing force and timing to the control unit 136. Further, the calculation unit 135 calculates the optimum voltage and the timing of applying the voltage from the thickness information of the recording medium such as a booklet, and the control unit 136.
The variable high voltage power supply 120 is controlled through the.

The print data may be sent by communication from another computer or the like. Further, when the computing unit 135 determines that the booklet 133 needs the format printing for printing the predetermined frame or field and the required character or number format, the format printing information and the information to be written in the format are calculated. Part 135 sums up. The format print information may be stored in the ROM or the like.

Further, the print data is subjected to font expansion by the arithmetic unit 135, and the laser or LED 1 is placed on the photosensitive drum 111 charged by the charger 115.
A toner image is formed by 13 and the developing device 112. The toner image is transferred onto the booklet 133 by the electric field applied by the variable high voltage power supply 120 between the photosensitive drum 111 and the transfer roller 117.

In this embodiment, transport fixing rollers 125 and 127 are provided as fixing devices, and drive sources 123 and 1 are provided, respectively.
The fixing unit 29 includes 29 and springs 124 and 128, and at this time, the calculation unit 135 determines the fixing pressure applied to the booklet 133 from the information of the thickness detection sensor 110 and the information such as the transport speed. By controlling the drive sources 123 and 129,
Appropriate transfer pressure is applied to the booklet 133.

Further, although not explicitly shown in FIG. 9, the photosensitive drum 111, the LED 113, the developing device 112, the charging device 115, the cleaner 116 and the like are driven up and down to drive the booklet 13.
3 makes the transport path 160 movable in both directions A and B. After printing the booklet 133, the image information reading unit 1 is used to determine the print density of the print data.
The booklet 133 is moved to a predetermined position 05.

The information obtained by the image information reading section 105 is passed through the image information recognizing section 131 and the interface section 134, and the calculating section 135 determines whether or not the print data satisfies a predetermined print density value. To do. If the predetermined print density value is not satisfied, but the print density value is not less than the second print density value which is not an operational problem even if the density is lower than the predetermined print density value, a maintenance request signal such as a maintenance call is issued. An operation unit of an external computer or booklet printer (not shown) through the arithmetic unit and the control unit
Tell the operator.

The booklet 201 shown in FIG. 10 is format-printed by the booklet printer 200 shown in FIG. Format printing means printing on a blank booklet, for example, as shown in FIG.
A column 202 (format) for the amount B, the balance, etc. is printed. However, with the binding portion 203 as a boundary, the booklet 20
The thickness of 1 is different depending on the page, and the booklet is likely to bulge near the binding portion 203. Therefore, by controlling the pressing force at the time of fixing, the toner image on the film can be fixed on the booklet without being deformed.

[0033]

As described above, according to the present invention, it is possible to obtain an electrophotographic apparatus capable of accurately printing the characteristics such as characters and frames at a predetermined position even on a booklet having a binding portion such as a passbook. .

[Brief description of drawings]

FIG. 1 is a schematic side view of an embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of the embodiment shown in FIG.

FIG. 3 is a diagram for explaining the operation of the embodiment shown in FIG.

FIG. 4 is a diagram for explaining the operation of the embodiment shown in FIG.

FIG. 5 is a diagram for explaining the operation of the embodiment shown in FIG.

FIG. 6 is a diagram for explaining the operation of the embodiment shown in FIG.

FIG. 7 is a diagram showing a reaction force characteristic of a transfer roller using foamed rubber against compression deformation.

FIG. 8 is a diagram showing a relationship between a transfer pressure of a transfer roller onto a recording medium and a void rate.

FIG. 9 is a schematic side view of a booklet printer which is another embodiment of the present invention.

FIG. 10 is a diagram of a booklet on which a format is printed.

[Explanation of symbols]

1 Variable High Voltage Power Supply 2 Solenoid (Drive Source) 3 Spring 4 Transfer Roller 5 Earth 6 Thickness Detection Sensor 7 Drive Source 8 Elastic Member 9 Conveying Roller (Fixing Roller) 10 Conveying Roller 11 Paper Guide 12 Paper Pan 13 Thickness Detection Sensor 14 Conveying roller 15 Paper guide 16 Driving source 17 Elastic member 18 Conveying roller 20 Booklet (recording medium) 22 Photosensitive drum 23 Charging device 24 Exposing device 25 Developing device 26 Toner 100 Inserting port 101 Sensor 102, 103 Conveying roller 104 Magnetic information reading unit 105 Image reading unit 106, 107 Conveying roller 108 Drive motor 109 Paper guide 110 Sensor 111 Photosensitive drum 112 Developer 113 Laser or LED 114 Exposure unit 115 Charger 116 Cleaner 117 Transfer roller 118 Drive source 119 Spring 120 Variable High-Voltage Power Supply 121 Sensor 122 Conveyor Roller 123 Drive Source 124 Conveyor Roller 124 Spring 125 Conveyor Fixing Roller 126, 127 Conveyor Roller 128 Spring 129 Drive Source 130 Magnetic Information Recognition Unit 131 Image Information Recognition Unit 132 Paper Guide 133 Booklet 134 data interface 135 operation unit 136 control unit 160 transport path 200 booklet printer 201 formatted booklet 202 format 203 binding portion t _1, t _2, t ₃ the transfer roller deformation amount P _1, P _2, P ₃ transfer pressure

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Minoru Murakoshi 1 Ikegami, Haruoka-cho, Owariasahi-shi, Aichi Prefectural Office Hitachi Systems Co., Ltd. No. 1 Incorporated Systems Division, Office Systems Division, Hitachi, Ltd.

Claims (12)

[Claims] 1. An electrophotographic apparatus which prints a toner image on a toner image carrier such as a photosensitive drum on a predetermined page of a recording medium such as a booklet having a plurality of pages by a transfer unit such as a transfer roller. From the thickness detection means for detecting the thickness of the medium, and the information detected by the thickness detection means,
An electrophotographic apparatus comprising: a calculation unit that calculates a pressing force applied to the recording medium by the transfer unit; and a control unit that controls the pressing force based on the calculation result. 2. The electrophotographic apparatus according to claim 1, wherein the computing unit determines that the recording medium is the toner image carrier and the toner image carrier based on a position of the thickness detecting unit and a transport speed pattern of the recording medium. An electrophotographic apparatus, wherein a timing of contact with a transfer unit and a pattern of the pressing force applied to the recording medium by the transfer unit are calculated. 3. The electrophotographic apparatus according to claim 1, wherein the transfer voltage generating unit generates a transfer voltage applied between the transfer unit and the toner carrier, and the transfer voltage generating unit. A transfer current detection unit that detects a current flowing in the recording medium based on the generated voltage, and a transfer voltage control unit that controls the transfer voltage based on the detected current value are provided. Electrophotographic device. 4. The electrophotographic apparatus according to claim 1, 2 or 3, further comprising a toner image forming unit that forms a toner image on the toner image carrier. 5. The electrophotographic apparatus according to claim 1, 2, 3 or 4, wherein the toner image carrier and the transfer unit have a conveying unit that conveys the recording medium. Photographic equipment. 6. The electrophotographic apparatus according to claim 1, 2, 3, 4, or 5, further comprising a fixing unit that fixes the toner image on the recording medium, and the fixing unit presses the recording medium. An electrophotographic apparatus comprising a pressing force control means for controlling the pressing force applied. 7. A transfer means for transferring a toner image on a toner image carrier onto a recording medium which conveys the toner image, and a transfer voltage control means for detecting a current flowing in the recording medium during the transfer and controlling a transfer voltage. A transfer pressure control unit that detects the thickness of the recording medium during the transfer and controls the transfer pressure applied to the recording medium, and a fixing unit that fixes the toner image transferred onto the recording medium are provided. The timing at which the recording medium comes into contact with the toner image carrier and the transfer means and the pressure pattern applied to the recording medium by the transfer means are calculated from the position of the thickness detection means and the transport speed pattern of the recording medium. An electrophotographic apparatus having an arithmetic unit. 8. An electrophotographic apparatus which prints a toner image on a toner image carrier such as a photosensitive drum on a predetermined page of a recording medium such as a booklet having a plurality of pages by a transfer unit such as a transfer roller. From the thickness detection means for detecting the thickness of the medium, and the information detected by the thickness detection means,
The transfer means includes a calculating means for calculating the pressing force applied to the recording medium, and a control means for controlling the pressing force based on the calculation result, and the calculating means is the position of the thickness detecting means. From the conveyance speed pattern of the recording medium, the timing at which the recording medium comes into contact with the toner image carrier and the transfer unit, and the pattern of the pressing force applied by the transfer unit to the recording medium are calculated, Transfer voltage generating means for generating a transfer voltage applied between the transfer means and the toner carrier, and transfer current detection for detecting a current flowing in the recording medium by the voltage generated by the transfer voltage generating means. And a transfer voltage control unit that controls the transfer voltage based on the detected current value. 9. A toner image forming means for forming a toner image on a toner image carrier such as a rotating photosensitive drum, a conveying means for conveying a recording medium such as a booklet for transferring the toner image, and the conveying means. Thickness detecting means for detecting the thickness of the recording medium, transfer means for transferring the toner image on the toner image carrier to the conveyed recording medium, position of the thickness detecting means and conveyance of the recording medium Calculation means for calculating the timing at which the recording medium comes into contact with the toner image carrier and the transfer means and the pressure pattern applied to the recording medium by the transfer means from the speed pattern, and the calculation of the timing and pressure pattern A pressing force control unit that controls the pressing force of the transfer unit that presses the recording medium toward the toner image carrier based on the value; Transfer voltage generating means for generating a transfer voltage applied to the toner image carrier, transfer current detecting means for detecting a current flowing in the recording medium by the voltage generated by the transfer voltage generating means, and An electrophotographic apparatus comprising: a transfer voltage control unit that controls the transfer voltage based on a current value flowing in a recording medium; and a fixing unit that fixes the toner image transferred on the recording medium. 10. The electrophotographic apparatus according to claim 9, wherein the fixing unit includes a pressure applying unit that applies a pressure to the recording medium to be fixed, and a pressure control unit that detects and controls the pressure. And an electrophotographic device. 11. The electrophotographic apparatus according to claim 9, wherein the recording medium is cut paper or multi-part paper having a thickness of 0.2 mm or more. 12. The electrophotographic apparatus according to claim 1, wherein the recording medium is 0.2 m.
A printer capable of printing on cut paper or multi-part paper having a thickness of m or more.