JPH0423268B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exposure apparatus used, for example, in a copying machine.

An exposure device is an optical system that applies uniform light to a document placed on a document table via a lamp, etc., and projects the reflected light onto the surface of a photoreceptor through a lens, mirror, etc. to form an optical image. It is a device that includes.

For example, the exposure device used conventionally is
Examples include those shown in the figure. In the figure, 1 is a pair of carriage guide shafts,
It is installed parallel to the main body of the copying machine (not shown). First and second carriages 2 and 3 are fitted into this carriage guide shaft 1 so as to be able to reciprocate. A lamp 4 and a first mirror 5 are attached to the first carriage 2, and a second mirror 6 is attached to the second carriage 3. Light is applied to the original document 7, and the reflected light is reflected by the first mirror 5 and the second mirror 6.
The light is made incident on the lens 8 via. Furthermore, in order to scan the original 7 while moving the first and second carriages 2 and 3 so that the optical path length from the first mirror 5 to the lens 8 is constant, the second carriage 3 A movable pulley 9 is attached to the movable pulley 9, and a wire 10 with one end fixed is hung on the movable pulley 9. The intermediate portion of the wire 10 is fixed to the first carriage 2 and is wound around a wire drum 11, and reaches the movable pulley 9 again via a pulley 12 disposed opposite to the wire drum 11. It is strung up. Further, the other end of the wire 10 is fixed by being biased by a coil spring 13 or the like. The wire drum 11 provided in this way can be used with various clutches, such as reversible clutches 1.
4. Driving force from the motor 16 is transmitted via the speed change clutch 15 and the like. Further, a movement amount detector such as a micro switch 17 is provided along the carriage guide shaft 1, so that the movement amount of the first and second carriages 2 and 3 can be detected. Such an exposure apparatus includes the motor 16 and the clutches 14 and 1.
5 and the micro switch 1.
By detecting the amount of movement of the first and second carriages 2 and 3 using 7, the first carriage 2 can be reciprocated at twice the speed of the second carriage 3.

However, with such exposure equipment,
Since the amount of movement of the first and second carriages 2 and 3 is detected by the microswitch 17, when changing the amount of movement of both carriages 2 and 3 according to the document size, a large number of microswitches are required and the configuration is The disadvantages are that the detection becomes more complicated and the reliability of detection decreases. In addition, the clutches 14 and 15
Each time the switch is turned on and off, shock and vibration are generated in the first and second carriages 2, 3, etc., resulting in a blurred optical image. Furthermore, since significant vibration occurs when the first and second carriages 2, 3 are started, scanning by the lamp 4 etc. cannot be performed until this vibration is completely attenuated. Since the preliminary stroke of No. 3 has to be long, the device has the disadvantage of becoming larger.

The present invention has been made based on the above circumstances, and uses a pulse motor as a drive source to move an optical system, and adjusts the rotation amount of the pulse motor based on pulse motor drive data set in advance according to the size of the document. An object of the present invention is to provide an exposure apparatus that can simplify the mechanism by controlling the optical system, and at the same time can prevent the occurrence of shock and vibration when moving the optical system.

The exposure apparatus of the present invention will be explained below with reference to the drawings.

FIG. 2 is a schematic longitudinal sectional front view of a copying machine having an exposure device according to an embodiment of the present invention. 20 in the figure
is a document table fixed to the copying machine main body 21, and an exposure device 22 is provided below the document table. This is so that the lamp 23 and the first mirror 24 move together to sequentially illuminate and scan the surface of the document placed on the document table 20. A second mirror 26 for reflecting the reflected light from the mirror 24 and making it enter the lens 25 provided ahead of it.
is provided, and this second mirror 26 is
The optical path length from the mirror 24 to the lens 25 can be kept constant.
Furthermore, a fixed mirror 28 is provided to irradiate the light transmitted through the lens 25 onto the surface of a photoreceptor 27 provided approximately at the center of the copying machine main body 21, and the image of the original illuminated by the lamp 23 is An image is formed on the surface of the photoreceptor 27 by the exposure device 22. Further, a charger 29 is provided near the photoreceptor 27, and an electrostatic latent image is formed on the surface of the photoreceptor 27 charged by the charger 29 by the illumination during image formation. There is. This electrostatic latent image is visualized by applying a developer to it by a developing device 30. Further, a paper feeding device 33 consisting of a cassette 31 containing paper P, a conveyance roller 32, etc. is provided on the side of the copying machine main body 21, and the paper P sent out from this device comes into contact with a pair of registration rollers 34. After being aligned and aligned, it is conveyed to the circumferential side of the developed image formed on the surface of the photoreceptor 27. Then, the developer constituting the developed image is transferred onto the transported paper P by the transfer device 35, and then fixed by the fixing device 36 and taken out onto the tray 37. A cleaning device 38 is provided near the photoconductor 27, and the photoconductor 27 after the transfer is cleaned by the cleaning device 38. Further, the two-dot chain line in the figure indicates the conveyance path of the paper P.

Next, the exposure device 22 will be explained in detail, including FIGS. 3 to 8. FIG. 3 is a schematic perspective view showing one embodiment of the exposure apparatus of the present invention, FIG. 4 is a schematic cross-sectional view of the same apparatus, FIG. 5 is a block diagram showing the control means of the same apparatus, and FIG. 6 is a pulse FIG. 7 is an explanatory diagram showing the two-phase excitation system of the motor, FIG. 7 is an explanatory diagram showing the speed characteristics of the pulse motor, and FIG. 8 is a flowchart for explaining the operation of the device. In the figure, reference numeral 39 denotes a pair of carriage guide shafts, which are mounted parallel to the copying machine main body 21. This carriage guide shaft 39 has first and second shafts.
The carriages 40 and 41 are fitted together so as to be able to reciprocate. The structure of this fitting portion is as shown in FIG.
One end of the is fitted through a round bushing 42,
The other end is fitted only in the vertical direction shown in the fourth figure through a square bushing 43. Although not shown, a guide roller may be provided at the other end of the square bush 43 instead of the square bush 43, and this guide roller may be supported by one of the carriage guide shafts 39. The lamp 23 and the first mirror 24 are attached to the first carriage 40, and the second
The second mirror 26 is attached to the carriage 41, and the lamp 23 allows the document platen 20 to be
Light is applied to a document (not shown) fixed to the mirror 2, and the reflected light is reflected by the first and second mirrors 2.
The light is made incident on the lens 25 via lenses 4 and 26. Further, in order to move the first and second carriages 40 and 41, a first timing belt 44 is rotatably stretched around a pair of gears 45A and 45B, and this intermediate portion is attached to the first carriage 40. A second timing belt 46 is rotatably stretched around the pair of gears 47A and 47B, and an intermediate portion thereof is connected to the second carriage 41. In order to halve the moving speed of the second carriage 41 relative to the first carriage 40 and make the optical path length from the first mirror 24 to the lens 25 constant, the gear 45A is connected to the first transmission. For example, the gear 47A is connected to a first gear train 48, and the gear 47A is connected to a second transmission, for example, a second gear train 49, which has a deceleration rate twice that of the first gear train 48. Both gear trains 48 and 49 are the first gear trains 48 and 49.
It is connected to a second pulse motor 50 and a second pulse motor 51 to be driven. Note that the gears 45A and 47A have the same number of teeth and the same pitch. When using two pulse motors as drive sources in this way, the rotational speed of both pulse motors 50 and 51 can be adjusted by using the first and second gear trains 48 and 49 having the above-mentioned relationship. This has the unique effect of simplifying the configuration of the pulse motor control means without requiring separate controls. Further, by using a timing belt and a gear in combination, it is possible to prevent slips and has the unique effect of completely preventing discrepancies in the relative positions and relative speeds of the two carriages 40, 41.

Next, the control means 52 for driving the pulse motors 50, 51 will be explained. This rotates the pulse motors 50, 51 in accordance with the size of the document placed on the document table 20, and gradually accelerates (hereinafter referred to as slow-up) when starting the pulse motors 50, 51, etc. This is to gradually decelerate (hereinafter referred to as slowdown) when stopping after rotating at high speed. In FIG. 5, 53 is a read-only storage device (hereinafter referred to as ROM) as a storage means that stores various processing data.
54 is a timer, 55 is an input port, 56 is an output port, and these are controlled by a central processing unit (hereinafter referred to as CPU) as a control means for controlling these via a data bus 57 )58. The timer 54 is driven by a clock signal 59A from a clock generator 59, and generates a timeout signal 59B for each set phase switching time, which will be described later, and applies it to the CPU 58 as an interrupt signal. ing. The input port 55 is provided with selection means such as an input device 6 such as a digital switch.
0 is connected, and the document size can be specified. The output port 56 is for switching the excitation phase of the pulse motors 50, 51, and the excitation phase switching circuit of the pulse motors 50, 51 is activated by the excitation phase switching pulse as an excitation phase switching signal that is outputted from the output port 56. 61 control is performed.

Here, an example of the contents stored in the ROM 53 will be explained. For example, when a two-phase excitation method is adopted as the drive method for the pulse motors 50 and 51 consisting of phases A, B, and B, each predetermined excitation phase switching pulse interval (hereinafter referred to as phase switching time) Excitation is performed while sequentially switching the excitation phase (the shaded area indicates the excitation phase). When the speed characteristics of the pulse motors 50 and 51 are set to an acceleration period T ₁ , a constant velocity period T ₂ , and a deceleration period T ₃ as shown in FIG. 7, the phase switching time gradually increases during the acceleration period T ₁ . During the constant velocity period _T2 , the phase switching time is set at uniform intervals, and during the deceleration period _T3 , the phase switching time is set to become gradually longer. Each phase switching time set in this way is divided by the clock cycle time of the timer 54, and these values (hereinafter referred to as a timer set data group) are converted into a pulse motor drive data group (hereinafter simply referred to as data). It is stored in the ROM 53 as . Further, the exposure device 22 scans the original within the constant speed period _T2 , and this period should be expanded or contracted in accordance with the size of the original. This is to reduce the amount of movement of the carriages 40, 41 to the necessary minimum, thereby shortening the scanning time and thus the copying time. Therefore, a plurality of data groups including timer set data corresponding to various document sizes are stored in the ROM 53 in advance, and data can be stored in the ROM 53 simply by specifying the document size using the input device 60. One group out of the plurality of data groups is selected and sequentially executed according to the timer set data.

Next, the operation of the exposure apparatus will be explained with reference to the flowchart shown in FIG. The input device 6
0 to specify the original size corresponding to the original size, a signal corresponding to the specified original size is sent to the CPU 5 via the input port 55.
8. The CPU 58 determines whether or not the pulse motors 50 and 51 have started to drive, and if the drive has started, interrupts can be accepted, and the ROM 53
One data group corresponding to the specified document size is selected from among the plurality of data groups stored in the data group, the first timer set data in this data group is read out, and the timer 54 is set. After setting the timer 54, predetermined phases of the pulse motors 50 and 51, such as the A phase and B phase shown in the sixth figure, are excited via the output port 56. The excitation phase at the start of excitation of the pulse motors 50 and 51 is
The selection will be based on the memory of the CPU 58. When a timeout occurs based on the first timer set data set in the timer 54, a timeout signal 59B is output from this, so the CPU 58 detects this and accepts an interrupt, and the selected data is The second timer set data in the group is set in the timer 54, and the excitation phases A and B are switched to phase B by the excitation phase switching pulse output from the output port 56. Next, when the timeout signal 59B is output, the excitation phase is switched to A. In this way, the excitation phase is sequentially switched by the excitation phase switching pulse outputted from the output port 56 according to the timing based on the timer set data, and the pulse motors 50, 51
is rotated a predetermined amount. At this time, within the acceleration period _T1 , the phase switching time becomes gradually shorter, so the pulse motors 50, 51 slow up, and the first and second carriages 40,
41 is moved without vibration or impact load, and there is no need to lengthen the preliminary stroke by the lamp 23 or the like before starting scanning. Therefore, highly reliable scanning can be performed within the constant velocity period _T2 , and it is also possible to downsize the apparatus. Also, within the deceleration period _T3 , the phase switching time gradually becomes longer, so the pulse motors 50, 51 slow down, and the first and second carriages 40, 41 are stopped without vibration or impact. That will happen. When the pulse motors 50, 51 are rotated a predetermined amount, the timer set data of the selected data group becomes "zero".
Therefore, it is determined that there is no ROM data, the state becomes incapable of accepting interrupts, and the first scan is completed. At this time, the CPU 58 operates the pulse motor 5.
Since the initial positions of 0 and 51 are memorized,
The pulse motors 50, 51 are automatically returned to their initial positions to prepare for the next operation.
In addition, when scanning originals of different sizes, by operating the input device 60 in the same manner as described above and specifying the size of the original corresponding to the original size, one of the plural data groups stored in the ROM 53 can be scanned. One data group corresponding to the document size specification is selected and sequentially scanned.

It should be noted that the above embodiment is merely an example, and it goes without saying that each member may be replaced with another member having the same function. For example, as shown in FIG. 9, a connecting arm 62 is connected to the second carriage 41.
Attach the slider 63 through the slider 6.
3 is movably fitted into one of the carriage guide shafts 39, and this slider 63 and the second
The pair of gears 45 are attached to the side of the carriage 41.
A, 45B are rotatably installed, and this gear 45
The intermediate portion of the first timing belt 44 stretched between A and 45B is fixed to, for example, the copying machine main body 21, and the intermediate portion of the first and second timing belts 44 and 46 and the first carriage 40 are fixed to each other. It can also be applied to a system in which the gears 47A and 47A are connected together and only the gear 47A is driven by the second pulse motor 51. With this configuration, when the pulse motor 51 is driven in the same manner as described above, the gears 45A and 45B act like a movable pulley, so the first carriage 40 operates at twice the speed of the second carriage 41 without vibration. Since it is moved without impact and only one pulse motor is required, the device can be particularly simplified and costs can be reduced.

As is clear from the above description, in the exposure apparatus of the present invention, data for driving the pulse motor from when the pulse motor starts driving until it stops during one exposure operation is stored in advance in the storage means. The pulse motor is driven by switching the excitation phase by an excitation phase switching signal output according to this data. Moreover, since the pulse motor driving data corresponds to the document size, the optical system is driven by a distance corresponding to the document size. This makes it possible to reduce unnecessary exposure operations, increase the speed of continuous exposure operations, and reduce the amount of power and the like associated with unnecessary exposure operations.

Furthermore, in the exposure apparatus of the present invention, since the data for driving the pulse motor is stored in the ROM as a storage means, it is extremely easy to change, increase, or decrease the data. It can be easily applied to any size.

Further, in the exposure apparatus of the present invention, the control means selects a predetermined pulse motor drive according to the size of the document inputted by the input device from among the pulse motor drive data stored in the storage means. Since the data for driving the pulse motor is selected, even if there is a plurality of data for driving the pulse motor stored in the storage means, the data for driving the pulse motor according to the user's request can be arbitrarily selected. In other words, even if the original size is A4, it is extremely convenient when only B5 size exposure is required.

Due to the above-mentioned effects, the exposure apparatus of the present invention has the following effects:
This has the additional effect of simplifying the mechanism and at the same time preventing the occurrence of shock and vibration when moving the optical system.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of a conventionally used exposure device, FIG. 2 is a schematic longitudinal sectional front view of a copying machine having an exposure device according to an embodiment of the present invention, and FIG. 3 is an illustration of an exposure device of the present invention. FIG. 4 is a schematic cross-sectional view of the device, FIG. 5 is a block diagram showing the control means of the device, and FIG. 6 is a two-dimensional diagram of the pulse motor.
FIG. 7 is an explanatory diagram showing the phase excitation method, FIG. 7 is an explanatory diagram showing the speed characteristics of the pulse motor, FIG. 8 is a flowchart for explaining the operation of the device, and FIG. 9 is a diagram showing another embodiment of the present invention. It is a schematic perspective view. 22... Exposure device, 23... Lamp, 24...
First mirror, 25...lens, 26...second mirror, 27...photoreceptor, 28...fixed mirror,
39... Carriage guide shaft, 40... First carriage, 41... Second carriage, 4
4...First timing belt, 45A, 45B
... Gear, 46 ... Second timing belt, 4
7A, 47B...gear, 48...first gear train,
49... Second gear train, 50... First pulse motor, 51... Second pulse motor, 52... Control means, 53... ROM, 54... Timer, 55
...Input port, 56...Output port, 57...
Data bus, 58...CPU, 59...Clock generator, 60...Input device, 61...Excitation phase switching circuit.

Claims (1)

[Claims] 1. An apparatus that performs exposure by moving an optical system along the surface of a document, comprising: an input device for inputting the size of the document to be exposed; a pulse motor that drives the optical system; and a pulse motor that drives the optical system. an excitation phase switching circuit that drives the pulse motor by switching the excitation phase of the motor according to an excitation phase switching signal; and an excitation phase switching circuit that drives the pulse motor from when the optical system starts moving until it stops. a storage means storing at least two types of pulse motor driving data for each document size, according to the length of a constant velocity period of the pulse motor, which differs depending on the size of the document, and the size of the document input from the input device. , one of the pulse motor drive data stored in the storage means is selected, and the excitation phase switching signal of the pulse motor is switched to the excitation phase switching signal based on the selected pulse motor drive data. An exposure apparatus characterized by comprising a control means for outputting an output to a circuit.