JPH072356U - Electrophotographic printer - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide an electrophotographic information printing apparatus that provides high precision control of mechanical operation, greatly simplifies maintenance, and increases flexibility in structure and function. A separate drive means comprising an electronic stepping motor 38 mechanically coupled to a driven member, and a stepping motor with a predetermined number of pulses and pulse frequency associated with a program controlled control unit 35. And a device for operating the stepping motor 38 according to the operation sequence of the information printing device. [Effect] The control of the mechanical operation is highly accurate, the maintenance is greatly simplified, and the flexibility regarding the structure and the function is increased.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 According to the present invention, there are basically two types of information printing devices to be used in connection with a processing system of an electrophotographic printing device, which includes at least one driven member that is mechanically movable, preferably rotatable. Can be divided. In one type, the character information signal is printed on the paper by a printing device that operates with mechanical shock in association with the ink ribbon, similar to a manual typewriter. This type of printing device, particularly a matrix printer or a daisy wheel printer, is relatively slow, is mechanically rather unstable at present, and is limited to a certain number of characters in terms of printability.

The other type of printing device, which operates without mechanical shock, uses an ink jet printer or electronic copying technology associated with the dry copying technology known in common copiers to provide information. A machine that transfers the is typical. In particular, the latter machine includes a laser printer in which an electrostatic latent image is formed on a photoconductor by controlling a laser beam. The number of such machines is increasing because the printing speed is very high and the printable information is not limited to a certain number of alphanumeric characters that can be printed by one daisy wheel.

The electrostatic latent image is developed with toner powder and transferred and fixed on a sheet by using a well-known dry copying technique. Since such information printing devices have taken as a starting point the technology known from ordinary dry copiers, at present, some processing devices, namely photoconductor devices with movable photoconductors that can be charged, A video device for projecting optical information to a photoconductor device, a developing device in which a toner image system and a toner removing system are arranged to cooperate with the photoconductor device, and a photoconductor device in cooperation with the photoconductor device. Image transfer device for transferring the toner image on the photoconductor to a sheet-shaped printing material, a fixing device for permanently fixing the toner image on the printing material, and between and between the image transfer devices. It is designed in the same manner as an ordinary copying machine having a processing device such as a feeding device disposed between a transfer device and a fixing device.

In such a machine, a single motor is used as a driving means for a plurality of mechanically movable (usually rotatable) members such as a photoconductor drum, a sheet feeding roller, and a toner transport mechanism. In many cases, complicated transmission means are used between the drive means and the rotary members or between the manual rotary members.

As with conventional copiers, such designs are very cumbersome to maintain and often result in long downtimes. This is because, in the case of mechanical failure, it is usually necessary to carry out tedious and time-consuming repair work such as exchanging and adjusting individual parts.

[0006] Such drawbacks may ordinarily be tolerated by ordinary copying machines, but often they cannot be tolerated with respect to data and document processing systems. In such fields, alternative devices are used. Attempts have been made to address this by doing so, but the problem of increased costs remains.

The object of the present invention is to improve the precision of control of mechanical actuation, greatly simplify maintenance, and simplify structure of conventional electronic photography equipment by providing a simple structural design. The purpose of the present invention is to provide a newly designed electrophotographic printing device of the above type that overcomes the drawbacks of the above structure.

The above object of the present invention is to provide at least one sheet feeding device associated with a sheet feeding device for feeding one sheet to a sheet feeding path, a photoconductor, and a sheet reaching the sheet feeding path. An image transfer device provided in the paper feed path for transferring the toner image appearing on the movable photoconductor, and a means for conveying the sheet after the image transfer to a fixing device, The sheet feeder associated with the paper feeder comprises a dry copying system assembled as an independent and interchangeable module, and the photoconductor and the image transfer device are assembled as separate and independent interchangeable modules. , And each module is equipped with an independent drive means as a stepping motor mechanically connected to at least one rotatable member in the module, which is used for operating the printing device. An electronic device characterized in that the sequence-based operation is directly controlled by selectively supplying drive pulses of a predetermined pulse number and pulse frequency from a motor drive unit controlled by a programmed control unit. This is accomplished by providing a photographic printing device.

Examples of the processing device of the above type having a mechanical movement function include a developing device for transporting and contacting toner powder from a toner supplier to a photoconductor by a rotating magnetic brush, and for example, a rotating drum or a rotating device. There are photoconductor devices that drive belt-shaped photoconductors with drive rollers, as well as sheet feeders and fusers, each having one or more driven rollers.

As a result of the design as described above, each processing unit of said type can be configured in a separate module, which can be replaced individually, and each module interfering with other modules. Without being able to be individually inserted into and removed from the machine housing, it can be inserted into the frame structure of the machine housing.

[0012] Each of these processing devices is sensitive because it involves mechanical operation, but repair of its failure can be performed easily and quickly by replacement work. Since an electronic stepper motor is used as the drive means for each of these modules, no transmission mechanism is used between the modules or between each module and the common mote. This also makes it easy to access all parts of the device and greatly contributes to the maintenance of the information printing device.

The stepping motor provided in the processor is started by the common control unit. Preferably, this common control unit comprises a microprocessor, which initiates the mechanical movement function of each of the above-mentioned modules, as well as other operations within the operating cycle, such as the light emitted by the corona discharge line at a suitable stage during a series of operations. It is programmed to initiate the charging and discharging of conductors. By such control, the stepping motor is individually supplied with a pulse train, and rotates at a specified speed or by a specified angle without performing feedback or position detection. As a result, it provides essentially more accurate control than conventional drive means in dry copiers.

Furthermore, the processing device according to the invention also has the advantage that its movements and other operating functions can be changed individually by simple reprogramming of the control unit. Thus, in a particular machine, each processing unit of its modular construction can be modified in line with technological advances without the need to modify other parts.

In connection with the conventional dry copying type printing apparatus and copying machine, the effect of improving the control accuracy obtained by the processing apparatus of the present invention is particularly effective when used for sheet feeding of the information printing apparatus. Target. Therefore, a feature of the preferred embodiment of the present invention is that the processing device constitutes a sheet feeding device for feeding printing material sheet by sheet from the accumulation sheet group, and engages with the upper sheet of the accumulation sheet group. And a pair of feed rollers including one drive roller, at least one of which is directly connected to the electronic stepping motor.

As a special advantage, this embodiment makes it possible to use a large number of storage sheet groups. Thus, automatic switching of each accumulation sheet group can increase the sheet capacity of the machine, avoid interruption of operation after sheet feeding, or allow the machine to selectively use more kinds of sheets.

In order to obtain such an advantage, each of the rollers and the stepping motor can be incorporated in a closed sheet cassette having a discharge slit on one wall surface. In such an embodiment, a sheet ejection slit is disposed on one of the major sidewalls of the cassette aligned with the pair of feed rollers for receiving sheets from the ejection slits of other similar sheet cassettes. Is an appropriate design.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the embodiment shown in FIG. 1, the casing of the information printing apparatus (the side wall of which is removed) includes a vertical frame member 1 and a horizontal frame member 2. A support device (not shown) in the form of a slide rail for fixing the processing device, which is designed as an individually replaceable module, is fixed to these frame members.

The video module 3 to which the information signal code is supplied is, in the present embodiment, an electrically controlled line-scanning electro-optical device, the scanning direction of which is the optical transmission slit 4. As shown.

Such an electro-optical device can be constituted by, for example, a high-intensity cathode ray tube, and this video unit can be mechanically moved unlike other differential scanning devices. The advantage of not including the crossing member is obtained.

However, it is also possible to use a differential scanning device using a control laser beam. The optical module 5, which may be of a known design, consists of mirrors 6, 7 and images the optical information emerging from the image module 3 onto the movable photoconductor 8 of the photoconductor module 9.

As is well known, the photoconductor 8 may have a configuration in which a photoconductive coating is applied to a rotating drum. A developer module 10 is provided to operate in association with the photoconductor 8. The development module 10 includes a toner supplier 11 and a rotating magnetic brush that transports toner powder to the photoconductor to develop an electrostatic latent image on the photoconductor surface.

Further, in association with the photoconductor, a toner removing and collecting module 13 is provided, which is connected to the developing module 10 through a duct 14. The toner removal / collection module 13 is arranged above the module 10 with a space for passing optical information from the module 5 to the photoconductor 8.

A charging device comprising a corona discharge wire 15 is provided inside the module 13 or in connection with it. An image transfer module 16 having corona discharge lines is provided for discharging the photoconductor 8 and transferring the toner image developed by the developing module 10 to the sheet-like printing material.

A first feed module 17 is provided for feeding the sheet material from the accumulation sheet group to the photoconductor 8 and the image transfer contact portion. The feed module 17 is designed in this embodiment as a sheet feeding unit including a sheet feed roller group including a take-out roller 18, a driven roller 19 and several pressing rollers 20. This sheet feeding unit is incorporated in a sheet cassette which will be described in detail later.

After the image transfer, the information recording sheet is peeled off from the photoconductor 8 and transferred to the second sheet feeding module 21. This module comprises, for example, several belts 22, by which the sheet is transferred to a fusing module 23, where the transferred toner image is permanently fused to the sheet.

The module 23 may be a heat fusion type or a pressure type. Each module 3, 5, 9, 10, 13, 16, 17, 17, 21, 23 is designed as an independent, individually replaceable module, each of which is a mechanically movable part. (A rotating member in the illustrated example). That is, each of the modules other than the modules 3, 5 and 16 has an electronic stepping motor as an independent driving means.

As is apparent from FIG. 2 showing the modules 9, 21 and 23, the stepping motors 24, 25 and 26 associated with these modules are respectively incorporated into the corresponding modules in this embodiment, Therefore, the flexibility in device design will be increased.

The external connection of each module is only the plugs 27, 28, 29 which are directly inserted into the terminal connectors 30, 31, 32 of the coupling unit 33, which may have the same design as the circuit board. The terminal connectors 30, 31, 32 are connected to a power supply unit 34 for supplying an operating voltage to each module, and are also connected to a common control unit 35 for program control. The plug may be fixed to each module shown in the figure, or may be connected to each module by a relatively short conductor, for example, a multicore flat cable.

The units 34 and 35, together with the interface module 36, are arranged on the side of the plate-shaped coupling unit 33 opposite to the modules 10, 21, and 23. The interface module 36 operates in a well-known manner as a coupling device according to a standard protocol applicable between the video module 3 and the electronic data processing system or the electronic document processing system.

FIG. 3 shows a design feature of a processing apparatus having a pair of rollers 19 and 20 which is indispensable for the present invention, for example, the sheet feeding unit described above. The driven roller 19 is connected to the output shaft of a stepping motor 38 via a toothed belt transmission 37, and the stepping motor 38 is supplied with drive pulses from a motor drive unit 39. In one modular design, the motor drive unit 39 is located inside the module or is fully integrated with the stepper motor 38. The motor drive unit 39 is connected to the program-controlled control unit 35 by a plug / socket connector 40. This control unit 35 is common to each stepping motor in some processors, as shown for output 41.

As is well known, the stepping motor 38 has several pulse driving windings, for example, four pulse driving windings. By driving the pulse driving windings from the motor driving unit 39, one driving pulse is generated. The stepping motor can be rotated by an angle, for example 1.8 ° or 3.6 °, in each direction depending on the drive winding switching method (not described). Therefore, the number of rotations or the angle of rotation performed in a constant operation step of the stepping motor is determined by the number of pulses, while the pulse interval or pulse frequency determines the rotation speed or acceleration of the stepping motor and the pulse power. In other words, the torque is determined by the product of pulse height and pulse width.

Therefore, by controlling the supply of the drive pulse from the motor drive unit 39 to the stepping motor 38, the stepping motor 38 is practically operated arbitrarily, and the member driven by the stepping motor is thereby controlled. In this case, the roller 19 can be operated arbitrarily.

FIG. 4 and FIG. 5 show an example of such control. FIG. 4 is an operating diagram of, for example, the roller 19, showing the speed V as a function of time t. In this example, the actuation process represented by curve 42 consists of an acceleration stage 42a followed by a constant speed rotation stage 42b. Such an operating process can be realized by a pulse train of the form shown very schematically in FIG. Here, in the first part corresponding to the acceleration stage 42a, the pulse interval gradually decreases and the pulse frequency gradually increases, and then the pulse interval is kept constant in the next pulse train part corresponding to the rotation stage 42b. .

The control unit 35 starts and controls the drive pulse generation operation in the motor drive unit 39. The control unit 35 can be configured by providing a microprocessor with an internal clock unit and a program memory (for example, EPROM type memory) in a well-known manner. The program memory of this microprocessor contains a program or subroutine for the actual actuation of each stepper motor controlled by the microprocessor during its entire operating sequence, as well as a control unit. It contains the main program for the entire operating sequence to be performed by the knit-controlled processor.

Each of these subroutines constitutes complete information about the pulse train to be generated by the motor drive unit 39 to carry out the desired operation. The motor driving unit 39 is controlled by a pulse generator that generates a driving pulse of a pulse power required to obtain a desired torque and information provided by the control unit, and stepping corresponding to a desired rotation direction. It consists of a logic circuit that determines the switching method of the motor winding, and that supplies drive pulses to the stepping motor as a pulse train of a specified number of pulses and a specified pulse interval.

For a particular machine configuration, each required actuation function in the overall actuation sequence is unchanged, as are the drive pulse provided by the motor drive unit 39 and the associated subroutine of the microprocessor, so that each subroutine is It is permanently burned into the program memory.

However, if the program memory is designed as an EPROM type memory, any stored actuation function can be easily reprogrammed so that only the actuation parameters for one processor are different from those of another processor. Can be changed independently without interfering with the function.

As a specific example of the processing device, a feeding module 17 designed as a sheet feeding unit is shown in FIG. In this example, the sheet feed rollers 19, 20 and the guide wall 43 cooperating therewith are positioned below the sheet discharge port 44 of the sheet cassette 45 and outside the accumulation sheet group 46 in the sheet cassette. Since the sheet feeding rollers 18, 19 and the stepping motor 38 are incorporated in the sheet cassette 45, the sheet feeding mechanism can be simplified and the cost can be reduced.

Due to the cooperation with one or more cassettes 47 (only one is shown in FIG. 6) that are overlaid on the underside, the mouth 48 for receiving sheets from the cassette 47 is also a bottom wall of the cassette 45. The sheet feeding rollers 19 and 20 are aligned with each other, and a plurality of accumulating sheet groups can be used, and a wider variety of sheets can be selectively used.

The cassette 47 has substantially the same design as the cassette 45 with respect to the sheet take-out roller 49 and the sheet feeding rollers 50 and 51. However, in the case of the cassette 47, the guide wall 52 has a linear shape so that the sheet is fed into the gap between the rollers 19 and 20 of the cassette 45, whereas the guide wall 43 of the cassette 45 does not. Curved to limit the sheet feed path to the tool 16.

FIG. 7 is an enlarged view of the drive mechanism of the sheet feeding unit shown in FIG. In this example, the take-out roller 18 and the driven feed roller 19 are provided as members that must be driven to rotate and therefore must be drivingly coupled to the stepping motor 38.

The take-out roller 18 must rotate counterclockwise as indicated by the arrow in order to take out the upper sheet of the accumulation sheet group 46. The take-out roller 18 is connected to a gear 53, and the gear 53 is engaged with a drive gear 56 via a gear transmission mechanism including two gears 54 and 55, and the drive gear 56 has two gears. It is connected to the stepping motor 38 via a transmission mechanism including tooth belts 57 and 58.

The driven feed roller 19 must also rotate counterclockwise in order to feed the sheet through the gap between the driven roller 19 and the pressure roller 20, which is connected to the drive gear 56 through a gear transmission mechanism consisting of a gear 59. Has been done. As is evident from the direction of rotation of the gears 54, 55, 59 indicated by the arrows, in this configuration the drive gear 56 must rotate clockwise (arrow 18 ') during the operation stage of the take-out roller 18, The drive gear 56 must rotate counterclockwise (arrow 19 ') during the rotation of the driven roller 19. Therefore, it is necessary to rotate the stepping motor in the opposite direction at each rotation stage of the rollers 18 and 19 which are continuous with each other. However, as can be seen from the above description, by controlling the stepping motor 38 as described above, such switching of the rotation direction can be realized without difficulty.

The gear 53, which is connected to the take-out roller 18, is in driving engagement with the drive gear 56 during the operating phase of the roller 19 and, during most of this operating phase, also from the storage sheet group 46. A ratchet mechanism capable of rotating the gears 54, 55, the drive gear 56, and the stepping motor 38 in the direction opposite to the direction specified for the operation period of the take-out roller 18 due to the frictional engagement of the taken-out sheet. Alternatively, the take-out roller 18 and the gear 54 are connected by a floating mechanism such as a sprinkling mechanism.

It is therefore clear that a single stepper motor can drive various driven members of a particular processing device, such as rotating members, in their respective directions without hindrance during different operating stages of the operating sequence. Is. In particular, the drive mechanism of such a design is suitable for a processing apparatus such as the sheet feeding unit shown in the figure, which operates members that are relatively close to each other at different stages. If multiple driven members are operated at the same stage of the operating sequence, or if a fairly complicated transmission mechanism is required for connection with a common stepping motor, the stepping It may often be advantageous to use a motor.

[0046]

[Effect of device]

 Most notably in the case of a completely modular machine such as the information printing device described above, but especially when only a small number of processing devices are designed according to the invention, an effect of improving the control accuracy can be obtained. For example, a sheet feeding unit as described above, particularly one provided with some sheet cassettes, can be effectively used even if the other portions are made into a normal structure. Furthermore, the use of a stepping motor as the driving means is particularly effective in simplifying the module design as described above, but the processing device according to the present invention is effective even if it is not designed as a replaceable module. Is obtained.

Thus, there is nothing that prevents the sheet feeding unit as described above from being used in connection with the ordinary storage sheet group of the electrophotographic apparatus.

[Brief description of drawings]

FIG. 1 is a perspective view of an electrophotographic printing apparatus including a processing device according to various embodiments of the present invention.

FIG. 2 shows the connection of multiple modules to a coupling unit.

FIG. 3 is a block diagram illustrating control of a stepping motor in a processing device.

FIG. 4 is an operation diagram for explaining control of a stepping motor.

FIG. 5 is a pulse waveform diagram for explaining control of a stepping motor.

FIG. 6 is a diagram showing a configuration of a sheet cassette.

FIG. 7 is a partially enlarged view of FIG.

[Explanation of symbols]

 17 Feed Module 19 Driven Roller 20 Pressing Roller 35 Control Unit 38 Stepping Motor 39 Motor Drive Unit 46 Storage Sheet Group 45, 47 Sheet Cassette

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location G03G 15/00 516 2107-2H

Claims (7)

[Scope of utility model registration request] 1. At least one sheet feeding device (17) associated with a sheet feeding device (18, 19) for feeding a single sheet to the sheet feeding path, a photoconductor (8), and the sheet feeding path. The image to the image transfer device (16) and the fixing device (23) arranged in the paper feed path for transferring the toner image appearing on the movable photoconductor (8) for the sheet reaching the sheet. The sheet feeding device (17) including means for conveying a sheet after transfer, and related to the sheet feeding device (18, 19).
Consists of a dry copying system assembled as an independent replaceable module, the photoconductor (8) and the image transfer device (16) being assembled as another independent replaceable module, each module being Stepping motors (24,25,26,38) mechanically coupled to at least one rotatable member in the module
As an independent driving means, the operation based on the operation sequence of the printing apparatus is controlled by the programmed control unit (35) from the motor drive unit (39), which is the predetermined number of pulses and pulse frequency. By selectively supplying drive pulses,
An electrophotographic printing device characterized by being directly controlled. 2. A stepping motor (2) for driving a movable photoconductor (8), which is a rotating drum, by a belt.
4, 25, 26, 38), the control information for defining the driving function is EPRO in the control unit (35).
The electrophotographic printing apparatus according to claim 1, wherein the program routine is stored as a program routine in a program memory including an M device. 3. The take-out roller (18) and the driven feed roller (19) are the rollers (18, 19).
Are coupled to the same stepping motor (38) via transmission members (53-59) which are capable of operating sequentially with individually adjustable rotational speeds, directions and times. Item 3. The electrophotographic printer according to Item 2. 4. The stepping motor (38) in which the take-out roller (18) is in a direction opposite to a specified operation direction thereof.
The electrophotographic printing apparatus according to claim 2, wherein the electrophotographic printing apparatus is connected to the stepping motor (38) through a transmission member (53) that is movable with respect to rotation of the. 5. A pair of feed rollers (19, 2) including a take-out roller (18) and a driven roller (19) arranged to engage with an upper sheet of the accumulation sheet group (46).
0) and the at least one of the pair of take-out and driven rollers (18, 19) and the sheet feeding device (17) are directly connected to the stepping motor (38). The electrophotographic printing apparatus according to claim 1, wherein the electrophotographic printing apparatus comprises: 6. The roller (18, 19) and the stepping motor (38) are incorporated in a closed sheet cassette (45) having a sheet ejection slit (44) in one wall. Claim 3, Claim 4
Alternatively, the electrophotographic printing apparatus according to claim 5. 7. The sheet ejection slit is disposed on one of the main side walls of the cassette (45), and the first side wall of the cassette has a sheet from the ejection slit of another similar sheet cassette (47). 7. An electrophotographic printing apparatus according to claim 6, characterized in that a slit (48) is provided in the pair of feed rollers (19, 20) in order to receive it.