JPH01219857A - Exposing device - Google Patents

Abstract

PURPOSE:To protect a light source in abnormalities by specifying a maximum voltage as a voltage impressed on the light source and preventing the impressed voltage from exceeding it. CONSTITUTION:When a phase angle, corresponding to the impressing stop point of an AC waveform impressed on the light source 11 at each zerocross point, is successively increased from the start of exposing control by the control of a first voltage control means 14, the maximum value of the impressed voltage is gradually increased. On the other hand, this exposure device is provided with a second voltage control means 18, which maintains the voltage controlled by the first voltage control means 14 at the maximum voltage set by a maximum voltage setting means 13, from the time when a voltage comparing means 15 has detected the coincidence of the voltages to the time when a light quantity discriminating means 17 discriminates light quantity. Thus, the voltage is gradually impressed on the light source 11; and after it reaches the maximum voltage as a controlled value, the light quantity is increased, with the impressed voltage maintained at the maximum voltage, until it reaches a desired light quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an exposure apparatus such as a copying machine, and more particularly to an exposure apparatus using a light source lit by a filament, such as a halogen lamp or a certain type of tungsten lamp.

"Prior Art" Exposure devices such as copying machines use various light sources such as fluorescent lamps and halogen lamps. Among these, halogen lamps have the advantage that the lighting circuit is simpler than fluorescent lamps, and the exposure equipment itself can be made smaller, so they are widely used, especially in small copying machines. ing.

``Problems to be Solved by the Invention'' However, halogen lamps generally have a short lifespan compared to fluorescent lamps. This is because, in the case of a halogen lamp, (i) it is necessary to maintain a relatively high temperature inside the lamp in order to ensure a phenomenon called the "halogen cycle" in which tungsten halide is returned to tungsten, and (ii) it is necessary to maintain a relatively high temperature during exposure scanning. This is thought to be due to the fact that the filament inside the tube is prone to breakage due to vibrations, etc. Therefore, if the tube length of the halogen lamp is set to be long in relation to the size of the original to be scanned, or if the tube diameter is made small in relation to the size of the exposure device, it may be difficult to ensure a sufficient lifespan. there were.

SUMMARY OF THE INVENTION An object of the present invention is to provide an exposure apparatus that can extend the life of a light source lit by a filament, such as a halogen lamp or a certain type of tungsten lamp.

"Means for Solving the Problem" In the invention as claimed in claim 1, as shown in principle in FIG. , maximum voltage setting means 13 for limiting the maximum voltage applied to the light source 11 is provided. Then, under the control of the first voltage control means 14, for example, the phase angle corresponding to the application stop point of the AC waveform applied to the light source 11 from each zero cross point is sequentially increased from the start of the exposure control. As a result, the maximum value of the applied voltage increases sequentially.

On the other hand, this exposure apparatus includes voltage comparison means 15 for comparing the applied voltage controlled by the first voltage control means 14 with the maximum voltage set by the maximum voltage setting means 13, and a light amount detection means for detecting the amount of light from the light source 11. means 16 and light amount detection means 16
is less than the specified light intensity.

Light amount determining means 1 that determines when the above light amount is detected
7, and the voltage controlled by the first voltage control means 14 is set to the maximum voltage setting means 1 from the time when the voltage comparison means 15 detects the coincidence of the voltages until the light amount determination means 17 makes a determination.
A second voltage control means 18 is provided which fixes the voltage to the maximum voltage set by No. 3.

Therefore, a voltage is gradually applied to the light source 11, and after reaching the maximum voltage as a limited value, the applied voltage remains fixed at that voltage until the desired amount of light is reached. will continue to increase.

Further, in the invention according to claim 2, the first voltage control means 1
A first phase angle control means 14' performs the voltage control of No. 4 by phase angle control. In this case, the second voltage control means 18 controls the first phase angle control means 14' from the time when the voltage comparison means 15 detects the coincidence of voltages until the light amount determination means 17 makes the above-mentioned determination. This is embodied in a second phase angle control means 18' that fixes the phase angle to the phase angle at the time when voltage coincidence is detected.

In the invention according to claim 3, the third phase angle control means 21 is used to adjust the phase to an angle corresponding to a temporary target voltage for controlling the light amount to be constant from then on when the desired light amount is obtained. We will set the angle.

This is to lower the voltage applied to the light source from a fixed value to a target value to reduce voltage overshoot.

Furthermore, in the invention according to claim 4, the fourth phase angle control means 2
2 to keep the light level constant. The method is to calculate a phase angle based on the scene detected each time by the light amount detection means 16 and the prescribed light amount, and to determine the voltage applied to the light source 11 each time based on the obtained phase angle. The inventions set forth in claims 3 and 4 further embody the invention set forth in claim 2.

As described above, according to the present invention, an excessive voltage is not applied to the filament, and the applied voltage gradually increases, so that the life of the light source can be extended.

``Example'' Hereinafter, the present invention will be described in detail with respect to an example in which the present invention is applied to a copying machine.

"table of contents" First, a table of contents in the description of the copying machine of this embodiment will be shown.

(1) Overview of the copying machine (2) Overview of the circuit configuration of the copying machine (3) Console panel (4) Specific circuit configuration (4-1) Around the photoreceptor drum (4-2) Optical system (4-3) ) Fixing device (4-4) Pilling counter (4-5) Power source (5) Details of N-light device (1) Overview of copying machine FIG. 2 shows the external appearance of the copying machine of this embodiment. The main body of this copying machine 31 includes a copying machine main body 33 placed on a dedicated cabinet 32, and three types of cassette trays 34 to 3 removably arranged on this copying machine main body 33.
6, and an output tray 37 for outputting copy paper.
It is made up of. At the top of the copying machine main body 33,
A platen cover 38 that can be opened and closed is attached.
Although it is not visible in the drawing, a platen glass is placed below it. Since this copying machine can copy up to A2 size originals according to the Japanese Industrial Standards, the platen glass has a size slightly larger than the area of this maximum size original.

A console panel 39 is arranged on the upper surface of the copying machine main body 33 in front of the platen cover 38. Although this console panel 39 will be specifically explained later, a liquid crystal display board is incorporated together with various key switches for manual operation. Various information such as the number of copies and jams (paper jams) are displayed on the liquid crystal display board.

A manual feed tray 41 is attached to the right side of the copying machine main body 33 in the figure. When manually feeding copy paper, the manual feeding tray 41 is folded down and the copy paper is manually fed from there. In this copying machine, in addition to the manual feed tray 41, three types of cassette trays 34 to 36 are provided as described above, so that copy paper can be supplied in four systems. In this case, the maximum size of copy paper that can be set in the cassette trays 34 to 36 is A3 size. Similarly, the maximum size of copy paper that can be manually fed from the manual feed tray 41 is set to A3 size.

FIG. 3 shows an outline of the internal structure of this copying machine. A platen glass 51 for placing an original (not shown) is arranged at the upper part of the copying machine main body 33. Directly below the platen glass 51, a light source 52 made of a halogen lamp is reciprocated by a carriage (not shown), and the original is exposed and scanned. The light beam reflected from the strip-shaped exposure area is reflected by the first to third mirrors 53 to 55, and then enters the optical lens 56. The light beam that passed through the optical lens 56 is
After being reflected by the fourth mirror 57, the exposure position 59 of the photoreceptor drum 58 is irradiated.

The photosensitive drum 58 is rotated at a constant speed in the direction of the arrow (clockwise) by a main motor to be described later, and its surface is uniformly charged by the action of the charge corotron 61. This charged area is the exposure position 5
9, the image of the electrostatic layer is formed by being irradiated with light reflected from the original and selectively eliminating charges. After unnecessary portions of this electrostatic latent image are removed by an interimage lamp 62, it is developed by a developing device 63 to create a toner image. This toner image will be transferred to a copy sheet (not shown) by the action of transfer corotron 64 and black corotron 65.

At this time, the toner remaining on the photosensitive drum 58 is neutralized by the pre-clean corotron 66 and then scraped off from the drum surface by the doctor blade 67.

When the cleaning of the photoreceptor drum 58 is completed in this way,
This drum surface is charged again by the charge corotron 61 and is ready for the next exposure operation.

By the way, as already explained, this copying machine is equipped with four systems of paper feeding mechanisms. 3 cassettes)) Ray 34
A size sensor 71 is arranged in front of each of the storage positions in which trays 36 to 36 are inserted, and is adapted to determine the size of the copy paper stored in these trays. There are various methods for this determination. In the copying machine of this embodiment, each of the cassette trays 34 to 36
A size sensor 71 detects the unevenness specific to the paper size at the tip of the paper and turns on or off each switch connected in series to each resistor of a circuit in which a plurality of resistors are connected in parallel. .

As a result, a resistance value corresponding to the detected size of copy paper is output as analog data.

A CPU (central processing unit), which will be described later, inputs this analog data and determines the size of copy paper.

A no-paper sensor 72 is located near each size sensor 71.
is located. Furthermore, feed rollers 73 are arranged above the front portions of the cassette trays 34 to 36, respectively. The feed roller 73 feeds the cassette trays 34 to 36.
It is used to feed copy paper from the selected tray.

The no-paper sensor 72 is a sensor that detects that there is no copy paper in the cassette tray when the feed roller 73 is not feeding the copy paper.

On the other hand, a feed roller 73 is also arranged at the tip of the manual feed tray 41, and feeds manually fed copy sheets one by one into the main body of the copying machine at a predetermined timing. The manual sensor 75 is a sensor for detecting that manual insertion has been performed. On the condition that the manual sensor 75 detects copy paper for one second or more, the CPU recognizes that copy paper is set in the manual feed tray 41. This is to prevent the copying operation from starting in such a case since the operator may pull out the copy paper immediately without manually feeding it.

The manual solenoid 76 is used for gate control to control the start of copy paper feeding. The manual solenoid 76 is positioned to prevent the passage of copy paper, and the gate opens when the copy cycle begins. As a result, driving force is transmitted to the feed roller 73 of the manual feed tray, and feeding of the copy paper is started.

Now, the copy paper selectively sent out from these four systems of paper feeding mechanisms advances along a conveyance path 77 shown by a broken line in the figure. Then, the arrival of the copy paper is detected by a feed sensor 78 arranged at a place where these conveyance paths 77 are integrated.

The conveyance of the copy paper does not necessarily start accurately due to slippage of the feed roller 73 or the like. Therefore, the conveyance of the copy paper is temporarily stopped by the registration gate 79, and the conveyance timing is adjusted. When the registration gate solenoid (not shown) is demagnetized and the registration gate 79 is opened, the copy sheet begins to be conveyed and passes between the photosensitive drum 58 and the black corotron 65, where the toner image is transferred. The copy paper on which the toner image has been transferred is conveyed by a conveyor belt 81, and passes between a heat roll 82 and a pre-rash roller 83 provided on the exit side thereof. The heat roll 82 is heated by a built-in quartz lamp, and the toner image is heated and fixed onto the copy paper here. The copy paper after the fixing is discharged onto the discharge tray 37 by a discharge roll (not shown).

Note that the three systems of cassette trays 34 to 36 used in this embodiment do not necessarily have to accommodate copy sheets of different sizes. For example, two trays 34, 35 containing copy sheets of the same size may be used. In this case, there is no copy paper in the selected cassette tray (
Then, the other cassette tray is automatically selected and copy paper is continuously fed.

In addition, in this copying machine, the registration gate (registration gate) 7 is demagnetized by the registration gate solenoid.
9 is opened, so that when the register gate 79 is closed, the solenoid is energized. Therefore, there is an advantage that positional fluctuations of the registration gate 79 in a state where copy paper is blocked from passing are reduced, and the leading edge of the copy paper can be accurately positioned.

(2) Overview of the circuit configuration of the copying machine FIG. 4 shows the main parts of the circuit configuration of the copying machine, centering on the CPU (central processing unit).

The CPU 91 of , :, has an AD converter, USART (
Universal 5ynchronous / A
synchronousReceiver Trans
It has functions such as a timer/counter, an input/output board, etc., and is connected to the following parts via a bus 92 or via a terminal 93 for analog human power.

(a) Those connected via the bus 92.

(i) ROM 94: This is a read-only memory that stores various programs for this copying machine, and has a capacity of 32 bytes in this embodiment.

(II) RAM 95: This is a random access memory that temporarily stores various data, and has a capacity of 2 bytes in this embodiment.

(iii) Non-volatile memory 96: Random memory backed up by a battery (not shown)
This is access memory and stores data that should not be erased even when the copier is turned off. Such data includes, for example, (a) a set-up value for adjusting the registration of copy paper, (b) a setting value for the amount of erasure of the leading edge of the image by the inter-image lamp 62 (FIG. 3), (C) Fine adjustment value of vertical and horizontal magnification when copy magnification is set to same size, (d
) Adjustment values of various parameters performed on the production line of copying machines, (e) History data recording situations such as copying machine jams, (f) Data specifying cassette trays to be used preferentially, etc. can.

(iv) Keyboard/Display LSI 97: This is a large-scale integrated circuit provided in the console panel 39. This will be explained in detail later.

(v) Timer/counter LSI 98: This is a large-scale integrated circuit that sets timing for controlling the driving of the main motor 101 and carriage motor 102. Here, the main motor 102 includes the photosensitive drum 58, the conveyor belt 81, and the heat roll 82 shown in FIG.
This is a motor used to drive etc. Carriage motor 1
02 is the light source 52 and optical lens 5 also shown in FIG.
This is a drive source for reciprocating a carriage (not shown) for scanning 6, etc.

(vi) I10 controller 103: This is an input/output controller that inputs various digital data via the filter circuit 104 and controls the drive of various components via the driver circuit 105. Here, various switches and sensors are connected to the filter circuit 104, for example. Also connected to the driver circuit 105 are clutches (not shown) that control the driving of the four systems of feed rollers 73 shown in FIG.

(b) Connected to the CPU 91 via the analog input terminal 93.

(i) Light quantity sensor 107: In this copying machine, a monitor lamp (see FIG. 9 later) for monitoring the light quantity is arranged in parallel with the light source 52. The intensity of the light from the monitor lamp is detected by a light amount sensor 107, and is input as analog data to the CPU 91 from a terminal 93 and processed.

(ii) Temperature sensor group 108: This copying machine is equipped with a soft touch sensor (see FIG. 8 later) that lightly contacts the roll surface in order to detect the surface temperature of the heat roll 820 shown in FIG. ing.

Analog data output from the sensor neck is similarly input to the terminal 93 and processed.

(iii) Size sensor group 71: This is a sensor group for detecting the size of copy paper stored in each cassette tray 34 to 36 shown in FIG. This copying machine is provided with a cassette tray as a standard specification that individually accommodates the following six types of standard size copy paper. Of course, it is also possible to use other foreign-spec cassette trays such as legal size.

(a) Japanese Industrial Standards B5 size paper horizontally fed (b) Japanese Industrial Standards 85 size paper fed vertically (c) Japanese Industrial Standards A4 size paper fed horizontally (d) Japanese Industrial Standards A4 size paper fed vertically (e) Japanese Industrial Standards A3 size paper horizontal feeding (f) Japanese Industrial Standards A3 size paper horizontal feeding As many types of cassette trays are selected and used, four sensors were placed on each cassette tray to distinguish between them. If a conventional data processing method is used, the CPU 91 would require a maximum of 12 input ports. In addition, the number of connectors and the number of cables constituting the harness increase, causing problems in terms of device cost, miniaturization, and reliability requirements.

Therefore, in the copying machine of this embodiment, the size sensor 71 consisting of a resistor and a switch is prepared in each storage location of the cassette tray as described above, and the data of the combined resistance value based on the on/off state of each switch is converted into CPI as analog data.
Send to J91. This makes it possible to identify up to 16 types of cassette trays.

(c) Others The reset circuit 109 is connected to the reset terminal 111 of the CPtJ91. This reset circuit 109 supplies a reset signal to the CPU 91 to reset it when the CPtJ 91 runs out of control or is initialized.

(3) Console Panel FIG. 5 shows the console panel used in this copying machine.

A menu display board 12 is provided on the upper part of the console panel 39, etc.
1 are arranged, and the contents of each panel part are displayed in characters. Below, these panel parts will be explained in order.

(a) A2 original mode: This copying machine can copy up to A2 size originals. However, since copy paper can be used up to A3 size, when an A2 size original is used, the image information of the entire original cannot be reproduced unless it is reduced. When the A2 original mode button 123 is pressed, the two display lamps 124 disposed above the button turn on one by one, and one of the two modes is selected.

Here, the display lamp 12 of the item marked rA2→A4J
4 lights up, A of the cassette trays 34 to 36
A tray containing 4-size copy paper is selected, the reduction ratio is set to 50%, and a copying operation from A2 size to A4 size is selected. On the other hand, rA2→
When the display lamp 124 for the item labeled A3J lights up, the tray containing A3 size copy paper is selected from the cassette trays 34 to 36, the reduction ratio is set to 70%, and A2 size copy paper is stored. From there, copying work to A3 size will be selected.

Of course, if the operator does not press the A2 original mode button 123 and sets the reduction ratio to 70% and selects the A3 size cassette tray, then rA2→A3J
Copying operations similar to those described above can be performed. The "A2 original mode" panel section is provided for the purpose of performing such work more easily and without errors.

(b) Original size: When the original size button 125 is pressed, the four display lamps 126 arranged in a row on this page will light up one by one,
Originals from 35-size to A3-size are selected in order. As will be explained later, this device also allows you to select the copy paper size, and when both selections are made, the reduction ratio is automatically calculated and set based on these relationships. ing.

(C) Reduction/Enlargement; This column is provided with a magnification display section 128 that displays the reduction ratio from 50% to 200% in 1% increments. The reduction ratio can be specified using either the two arbitrary % specification keys 129 located below this magnification display section 128 or the fixed size specification key 1.
This can be done by operating 31.

When the upper key of the arbitrary % designation keys 129 is pressed, the magnification increases by 1% up to a maximum of 200%.

Also, if you press the key located at the bottom, at least 50%
The magnification decreases by 1% until

There are four display lamps 1 above the fixed size designation key 131.
32 are arranged. These are 100%, 63%, 121% and 135% as fixed magnifications respectively
It is for displaying. Fixed size specification key 13
When 1 is pressed, these display lamps 132 are selected one by one in turn.

Note that the three types of magnification other than 100% can be freely changed by the operator according to the content of the work.

(d) Paper tray: A tray selection button 134 is arranged in this column.

When the tray selection button 134 is pressed, three types of display lamps 1 each displaying the three cassette trays 34 to 36 are displayed.
35 light up one by one, and the selection status of the tray is displayed. To the left of these display lamps 135, six display lamps 136 are arranged to display the type of copy paper selected at that time.

Here, "A4/B5 horizontal" is used to indicate that a cassette tray with A4 size or 35 size copy paper set in the horizontal direction has been selected, and these cassette trays are used. cases are usually rare, so
It is designed to be displayed in a unified manner. Depending on the copying machine, these may be displayed individually. Also,
“Non-standard” indicator lamp 1 under “A4/B5 horizontal”
36 is provided to standardize the selection of a cassette tray containing copy paper sizes other than these sizes.

(E) Copy density; Two copy density buttons 138 are provided in this column. Five types of display lamps 139 are arranged above these buttons 134, each standardizing five levels of copy density, and one of these is selectively displayed by button operation, and that copy density is selected. It looks like this.

(F) Display/Key Operation This column includes a display section 141 and a key operation section 142 in which various keys are arranged.

(a) Display section 141: Here, a display section 144 showing the selection status of the cassette trays 34 to 36, a display section 145 showing the number of copies, and various situations of the copying machine are displayed! 1146 are arranged. Display section 14
The characters displayed in 6 include "paper jam,""ready to copy,""pleasewait," and "wrong cassette." These characters are displayed by selectively lighting up light emitting diodes provided at the back.

Note that "cassette wrong" is a blinking character that is displayed when the combination of original size, copy paper size, and reduction ratio is abnormal and a copy error is expected. Even when this display is displayed, copying can be performed.

(b) Key operation B142: The following various keys or buttons are arranged here.

(i) Page continuous shooting button 151: This button is used to implement the page continuous copying function.

Here, the page speed copying function refers to the ability to print 2 pages like a bound manuscript.
This is a function that divides a spread document into two pages each and copies them one after the other. When the page continuous shooting button 151 is pressed, a display lamp 152 disposed near it lights up, indicating that the page continuous shooting function has been selected. When the page continuous copying function is selected, the reduction ratio is automatically set to 100% (same size), and a cassette tray containing "A4/B5 landscape" copy paper is selected.

(ii) Program button 153: This is a button for setting the copying machine to a mode used when writing various data to the nonvolatile memory 96. Such data includes, for example, data for setting the tray to be selected preferentially (priority tray) from among the three types of cassette trays 34 to 36, and data for setting the power supply when no copying work is being performed. There is data on the time required to execute a power saving function that shuts off part of the system.

The CPtJ91 stores non-volatile memory for priority handling items such as the cassette trays 34 to 36 and the reduction ratio when the copying machine is in the initial state when the power is turned on or when it returns to the initial state for some reason. 96 is checked, the console panel 39 is displayed accordingly, and the copying machine is set to the instructed state. When the program button 153 is pressed, a display lamp 154 disposed near the button lights up to indicate that the copying machine is set to a mode for making various settings.

(iii) All clear button 156: This button is used to return each mode to its initial state.

(1v) Numeric keypad 157: These are numeric keys and are used to set the number of copies, etc.

(v) Interrupt button 158: This button is used to temporarily interrupt the copying operation currently in progress and enable the copying operation under other copying conditions. When the interruption ends, the copying operation can be resumed under the previous copying conditions.

(vi) Stop button 159: This button is used to interrupt copying.

(V■) Start button 161: This button is used to start copying.

A display lamp 162 for displaying start reservation is arranged near the start button 161. When the start button 161 is pressed while the words "Please wait" in the display section 146 are lit, an instruction to start the copying operation is reserved and the display lamp 162 is lit. In this lighting state, the copying operation will automatically start when the text "Please wait" in the display section 146 goes out and "Ready to copy" is displayed instead.

As explained above, many keys and light emitting diodes (display lamps) are arranged on the console panel 39.

Therefore, if all these components were individually connected to the CPU 91, the number of ports would be insufficient. Therefore, in this embodiment, a keyboard/display LSI 97 (FIG. 4) is used as a solution to this problem. The keyboard display LSI 97 constantly monitors key presses.

Information as a result of monitoring is then transmitted to the CPU 91 in time-division as 8-bit data. Also, CPU9
The number of light emitting diodes (display lamps 124, 126, 132, 136, 139
．． 152, 153, etc.), control is performed to turn on these light emitting diodes or keep them in the off state.

(4) Specific circuit configuration Next, the specific circuit configuration of this copying machine will be explained.

(4-1) Around the Photoreceptor Drum As shown in FIG. 3, parts such as a charge corotron 61 are arranged around the photoreceptor drum 58. Since a general explanation has already been given regarding these, here the interimage lamp 62 and the parts that were not explained earlier will be explained.

(a) Inter-image lamp: Figure 6 shows the structure of the inter-image lamp. The inter-image lamp 62 consists of 80 light emitting diodes 221 arranged in a - column and one plastic lens 222 arranged in front of these. The plastic lens 222 has an aspherical convex portion at a position corresponding to each light emitting diode, so that even when adjacent portions of the light emitting diodes 221 emit light, the photosensitive drum 58 (see FIG. ), care has been taken to ensure that the intensity of light does not become uneven even in the boundary area between them.

The 80 light emitting diodes 221 are controlled to be turned on and off at predetermined intervals by a 5-bit signal output from the CPU 91. At this time, the 30 left and right light emitting diodes 221 are controlled to turn on and off with the same signal state at their symmetrical positions, and the 20 light emitting diodes 221 in the center are turned on at the same time with the same signal state.・It is controlled to turn off. For this reason, 8
The 0 light emitting diodes are controlled to be turned on and off using 31 types of control signals, and can be controlled using 5-bit data as described above.

(b) Toner sensor: This is a sensor (not shown) for determining whether it is necessary to replenish toner in the developing device 63.

(c) Dispensmoke: The developing device 63 is provided with a toner box (not shown) for storing toner. The motor used to stir and replenish the toner in this toner box (
(not shown). When an increase switch (also not shown) is pressed, this dispense smoke is forcibly driven to increase the amount of toner.

(d) High-voltage power supply (HVPS): A power supply (not shown) used to create a parallel electric field inside the developing device 63 and improve the reproducibility of the solid black part of the original. .

(E) Full toner sensor: Used toner is collected by the doctor blade 67, and this is a sensor (not shown) for detecting whether or not enough toner has been collected in the collection container.

(4-2) Optical system FIG. 7 shows the circuit portion related to the optical system. This copying machine is capable of scanning originals up to A2 size. Therefore, the tube length of the halogen lamp constituting the light source 52 is set to be somewhat longer than the length of the A2 size document in the lateral direction. The light source 52 is configured to reciprocate over a distance slightly longer than the longitudinal direction of an A2 size document as the carriage moves by driving the carriage motor 102.

The scanning speed of the carriage motor 102 is controlled by a reference clock output from the timer/counter LSI 98 shown in FIG. be done. Further, the start and stop of rotation and the rotation direction of the motor are controlled by a start signal and a rotation direction instruction signal output from the I10 controller 103 also shown in FIG. 4. Since these clocks and signals are all output from peripheral LSIs according to instructions from the CPU 91, it can be assumed that drive control of the carriage motor 102 is substantially performed by the CPLI 91.

The registration sensor 251 is a sensor used to detect the scanning position of the carriage. That is, a registration sensor 251 is fixed near the upper left end of the copying machine main body 33 shown in FIG. 3, and when the carriage is located near the scanning start position, an actuator (not shown) attached to this turns this sensor on and off. It is supposed to be done. This detection output of the register sensor 251 is taken into the CPU 91,
Timing control is performed using this timing as a reference to determine when to start transporting the copy paper, the scanning length of the carriage, and the like.

The lens/mirror sensor 253 is a sensor that controls the movement of the optical lens 56, mirror 53 (Fig. 3), etc.
It is composed of one detection element. The lens/mirror motor 254 has also been changed from a conventional copying machine in which the optical lens 56, mirror 53, etc. are driven separately to a type in which they can be driven in common. The optical system fan 255 is a fan for cooling the optical system and removing heat from the platen glass 51.

Among these optical system components, the light source 52 and optical system fan 255 are driven by an AC (alternating current) driver 257 of this copying machine. Further, the carriage motor 102, the registration sensor 251, the density control sensor 252, the lens/mirror sensor 253, and the lens/mirror motor 254 are
It is designed to be driven by a C (direct current) '74 source.

(4-3) Fixing Device Next, the circuit configuration of the fixing device will be explained. The fixing device is shown in a portion of FIG.

The fuser lamp 261 is arranged inside the heat roll 82 (FIG. 3), and the fixing control element (SSR) 262
The control is performed by

The surface temperature of the heat roll 82 is measured by the soft cut sensor 26.
3, and the temperature information is transmitted to the CPU 91. The user exit sensor 264 is an element for detecting that the copy paper that has passed through the heat roll 82 and the pressure roller M of the pressure roller 83 is ejected toward the paper ejection tray 37 without being accidentally caught in them. A fixing control element (SSR) 262 is driven by an AC driver 257, and a soft touch sensor 263 and a user exit sensor 264 are driven by a DC power source 258.

(4-4) Pilling counter As shown in Figure 8, this copying machine has a pilling counter 2.
71 is provided. The pilling counter 271 is a counter used for collecting copy fees, etc., and is designed to count the total number of copies made.

(4-5) Power supply Next, the power supply relationship will be explained with reference to FIG.

The copying machine main body 33 is connected to a 100V (volt) commercial power source. Also 115V60H for overseas use
It is also compatible with z and 220V50Hz power supplies. The power supplied from the outlet 281 is connected to a 15 ampere circuit breaker 282 and a noise filter 2.
83 to reach the main switch 284. The output side of the main switch 284 is the interlock switch 2.
85, an AC driver 257, and a fixing control element 262.
and DC power is supplied to R258 as a power source.

The AC driver 257 supplies power to the following components at predetermined timings.

(B) Light source 52 and optical system fan 255 (Fig. 7) (B) Fuser lamp 261 (Fig. 8) DC power supply 258
(b) Interlock switch 285 (Figure 8) supplies power to the following components at predetermined timings.
AC driver 257 (Fig. 8) (c) High voltage power supply device (d) User exit sensor 264 (Fig. 8) (e) Fixing control element 262 (Fig. 8) (f) Accessory 286 (
(FIG. 8); Here, the accessories 286 include, for example, a coin kit that allows copies to be made using coins, and key counters and key coders for managing copies in each department.

(G) Pilling counter 271 (Figure 8) (H) X-
Boat fan 287 (FIG. 8): This fan is a vacuum fan for sucking copy paper conveyed through a conveyance path called an X-port.

(S) Interimage lamp 62 (Figure 3) (N) Carriage motor 102 (Figure 7) (L) Registration sensor 251
, lens/mirror/sensor 253 and lens/mirror/motor 254 (Fig. 7) (w) Increase switch (5) Details of exposure device Fig. 9 shows the circuit configuration of the exposure device used in this example. This shows the main parts. The exposure device is already on the fourth
It is configured mainly around the CPU 91 explained in the figure.

A crystal oscillator 301 is connected between two terminals XI and X2 of the CPU 91, and a clock of a predetermined frequency is input thereto. Furthermore, a zero-cross detection signal 303 is inputted to the input terminal (1) from a zero-cross detection circuit 302, so that the timing of the zero-cross of the power supply is detected. Furthermore, the output terminal 0 of the CPU 91. From then on, the trigger signal 30 is generated at a timing that becomes earlier by the time width based on the zero cross timing.
4 is output. This trigger signal 30
4 is supplied to the exposure trigger circuit 305. In the exposure trigger circuit 305, a built-in three-terminal AC control element is thereby controlled on and off, and a light source 52 consisting of a halogen lamp provided on the output side is conductive for only the time that this element is turned on.

A lamp 306 is connected in parallel to the light source 52, and the amount of light from the lamp 306 is detected by a photodiode 307. This detection output is amplified by the light amount amplification circuit 309 and inputted to the input terminal I2 of the CPU 91.

Thereby, the CPU 91 can indirectly grasp the amount of light from the light source 52.

FIG. 10 is for explaining the exposure control of this exposure apparatus. Curve 32 represented by a thick line in this figure
1 represents the change in the applied voltage, and a curve 322 represented by a line thinner than this represents the change in the amount of light from the light source 52.

Exposure control consists of three stages.

(1) First, in the first step S1, the voltage applied to the light source 52 is stepped up in steps. Then, when a predetermined voltage (1) lower than the power supply voltage is reached, this first stage S1 is terminated.

In this example, the voltage 1 was set to 66 volts. By increasing the applied voltage to the rated voltage of 100μ, the light source 52, such as a halogen lamp with a particularly long tube length, can be
This is because, in view of the fact that the lifespan of the battery is short, the maximum value of the applied voltage is kept fairly low to extend the lifespan.

FIG. 11 shows control for stepping up the applied voltage. The applied voltage is controlled by sequentially increasing the energization time of each half-wave component of the AC power source by controlling the phase angle. The shaded area in the figure is the light source 5.
2 is the part to which voltage is applied. A voltage of 66V is achieved at a phase angle indicated at time T1 after a predetermined period of time has elapsed from the start of energization.

The voltage applied at the start of energization is a voltage equivalent to 9.5 mS (m seconds) in the case of a 5 QHz power supply,
This corresponds to approximately 2.9■. In addition, in the case of 60Hz, 7
．． This is a voltage corresponding to 8 mS, which corresponds to about 4.1 ■.

The applied voltage is increased each time the power supply crosses zero, but
This control is performed differently depending on whether the first copy is made or the second and subsequent copies when a plurality of copies are made. That is, in the case of the first sheet, the lighting time increases at a pitch corresponding to a phase angle of 200 μs (microseconds), and in subsequent cases, the lighting time increases at a pitch corresponding to a phase angle of 600 μs.

The reason why we decided to slowly increase the applied voltage over a longer period of time for the first copy than for the second and subsequent copies is because the time before exposure starts can be set longer. It is.

That is, in the case of the first sheet, press the start button 161 (
5), the conveyance of the copy paper starts, and after the copy paper has been conveyed to a certain extent, the platen glass 51
The exposure operation shown in FIG. 3 is started. On the other hand, when continuous copying is performed, conveyance of the copy paper has already started for the second and subsequent sheets, and it takes time until the light source 52 that has been turned off is turned on again each time one copy is completed. The interval will be shortened.

In actual copying operations, copies are often made one by one, and controlling the lighting more gently by separating the first copy from the second copy during continuous copying places a corresponding burden on the light source 52. This will greatly contribute to extending its lifespan.

(2) Next, in the second step S2, the voltage applied to the light source 52 is maintained at a constant voltage (2).

The CPU 91 controls the lamp 30 via the light amount amplification circuit 309.
6 is checked, and this constant voltage control is performed until time T2 when the light amount reaches the target value.

Note that the CPU 9 i performs similar monitoring in the first stage S1, and when the light intensity reaches the target value, the control of the first stage S1 is immediately terminated, and the control of the next third stage S3 is started. will be started.

(3) In the third step S3, the voltage applied to the light source 52 is first set to voltage ■2, which is lower than voltage ■. This voltage 2 is a target value voltage at which the light source 52 is expected to obtain the target value of light 1 under normal environmental conditions, and the phase angle corresponding to this voltage is the ROM 9 shown in FIG.
4 is stored in advance.

In this third step S3, the voltage applied to the light source 52 is changed to a voltage v
2, the applied voltage (phase angle) is controlled by feeding back the state of the light amount obtained from the light amount amplifying circuit 309 so that the target light amount is constantly obtained. Details of this control will be explained later.

FIGS. 12 and 13 show the above exposure control when changing the copying reduction ratio.

When the operator presses the A2 original button 123 shown in FIG.
31, the reduction ratio is changed accordingly.

When such an operation is performed, data of the corresponding reduction ratio from the target value table written in the nonvolatile memory 96 (FIG. 4) is read out (step 1 in FIG. 12).
Figure 2 Step ■). The data is then stored in the RAM 95 as a target value for the amount of light from the light source 52 in the copying operation (step 2 in FIG. 12).

FIG. 13 shows the exposure operation. When the state is reached in which the application of a half cycle of voltage to the light source 52 is started (step 2; Y), the initial phase angle setting in the first step S1 is performed (step 2). Then, the first energization control of the light source 52 is performed at that phase angle (step 2).

In the state where the energization in this half cycle is completed (step ■; N). The CPU 91 uses the light amount amplification circuit 309 to determine whether the light amount of the light source 52 has reached the target value (step 2). Here, the target value is the value stored in the RAM 95 in the operation explained in FIG. 12, and this target value also differs when the reduction ratio differs.

If the light intensity of the light source 52 has not reached the target value (N),
Set the amount to advance the lighting timing in a half cycle of the power supply. At this time, the CPU 91 determines whether the current exposure control is for the first copy or for the second and subsequent copies (step 2). In the case of the first photo, set the lighting timing to 20
Perform calculation to advance by 0 μs (step ■). In addition, in the case of the second and subsequent copies in continuous copying, step (2) is performed to advance the lighting timing by 600 μs.

Thereafter, it is determined whether the applied voltage corresponding to the phase angle as a result of these calculations has reached the voltage (2) described above (step (2)). If the phase angle has not been reached, the control in the first step S1 is continued, so that the energization of the light source 52 is controlled in the half cycle using the calculated phase angle (step ①).

In this way, exposure control is started from step (2) every half cycle. As a result of such control, the light source 52 gradually increases its visibility, and at a certain point the applied voltage becomes larger than the voltage (2) (step (2); Y). From this point on, control in the second stage S2 is started. That is, the CPU 91 sets the phase angle corresponding to the voltage (1) (step (2)), and uses that phase angle to control the energization of the light source 52 during the half cycle (step (2)). In this way, until the light amount reaches the target value (step ■;
N), exposure control is performed in a second step S2.

When the light intensity of the light source 52 reaches the target value (step ■; Y
), and thereafter, exposure control in the control mode is performed (step ■). This is the exposure control in the third stage S3. In the control in this control mode, the above-mentioned target value and the current amount of light supplied from the light amount amplification circuit 309 shown in FIG. 9 are calculated based on a predetermined calculation formula. Then, the phase angle in each half cycle of the power supply is set based on the result of this calculation. With such a feedback mechanism, the amount of light from the light source 52 is maintained at a desired level.

In the embodiments described above, a case has been described in which the light amount of the light source is controlled by controlling the phase angle, but the present invention is not limited to this. For example, it is also possible to perform control to increase the amount of light from the light source by changing the number of power pulses output within a predetermined time, or to perform control to maintain it at a predetermined value.

"Effect of the Invention" As described above, according to the invention of claim 1, the maximum voltage to be applied to the light source is defined and the applied voltage is prevented from becoming excessive, so the light source can be protected even in abnormal situations. Can be done. Further, according to the second aspect of the invention, since the voltage is controlled by the phase angle, fine control is possible, and high-quality copies can be obtained. Furthermore, according to the third aspect of the present invention, when the light amount rises, the voltage is set to a target value that does not cause scattering, and thereafter control using a constant light amount value is started. Therefore, this allows quick and reliable control. Further, according to the fourth aspect of the invention, since a predetermined calculation is performed based on the target value and the current measured light amount, highly accurate control is possible depending on the calculation content.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for explaining the present invention in detail, and FIGS. 2 to 13 are for explaining an embodiment of the present invention, of which FIG. 2 shows an exposure apparatus of this embodiment. 3 is a schematic configuration diagram showing an overview of the internal structure of this copying machine, FIG. 4 is a block diagram showing the main parts of the circuit configuration of the copying machine, and FIG. 5 is a plan view of the console panel, FIG. 6 is an explanatory diagram showing the structure of the inter-image lamp, FIG. 7 is a block diagram showing the circuitry related to the optical system of the copying machine, and FIG. 8 is a diagram showing the fixing device, power supply, etc. FIG. 9 is a block diagram showing the main parts of the circuit configuration of the exposure device. FIG. A waveform explanatory diagram showing the state of phase angle control when stepping up the voltage, Fig. 12 is a flow chart showing the work for setting the target value of light amount, and Fig. 13 is a flow chart showing the state of controlling the light amount. . 11.52... Light source, 12... AC power supply, 13... Maximum voltage setting means, 14... First voltage control means, 14'. ...
...First phase angle control means, 15... Voltage comparison means, 16... Light quantity detection means, 17... Light quantity discrimination means, 18... Second voltage control means, 18'...
... second phase angle control means, 21 ... third phase angle control means, 22 ... fourth phase angle control means, 91 ... cpu. 94...ROM. 95...RAM. 96...Nonvolatile memory, 107...Light level sensor, 302...Zero cross detection circuit, 305...
...Exposure trigger circuit, 306...Lamp, 307...Photodiode, 309...
...Light amplification circuit, V, ,V2... Voltage. Applicant: Fuji Xerox Co., Ltd. Agent

Claims (1)

[Claims] 1. A light source, an AC power supply for the light source, maximum voltage setting means for setting a maximum voltage to be applied to the light source, and a maximum voltage setting unit to set the maximum voltage to be applied to the light source at each time point. a first voltage control means for sequentially increasing the voltage; a voltage comparison means for comparing the applied voltage controlled by the first voltage control means with a maximum voltage set by the maximum voltage setting means; and a voltage comparison means for detecting the amount of light from the light source. light amount detecting means; light amount determining means for determining when the light amount detecting means detects a light amount equal to or greater than a predetermined light amount; and light amount determining means making the determination from the time when the voltage comparing means detects coincidence of voltages. An exposure apparatus characterized by comprising: a second voltage control means for fixing the voltage output-controlled by the first voltage control means to the maximum voltage set by the maximum voltage setting means. 2. The first voltage control means sequentially increases the phase angle corresponding to the application stop point of the AC waveform applied to the light source from each zero cross point from the start of the exposure control, so as to increase the maximum value of the voltage applied to the light source. and the voltage control means is voltage comparison means for comparing the applied voltage controlled by the first phase angle control means with the maximum voltage set by the maximum voltage setting means. , the second voltage control means adjusts the phase angle controlled by the first phase angle control means to the voltage from the time when the voltage comparison means detects the coincidence of the voltages until the light quantity determination means makes the determination. 2. The exposure apparatus according to claim 1, further comprising second phase angle control means that fixes the phase angle to the phase angle at the time when the coincidence of the two is detected. 3. The exposure apparatus according to claim 2, further comprising third phase angle control means for setting the phase angle to an angle corresponding to a predetermined target voltage at the time when the light amount determining means makes the determination. . 4. After the third phase angle control means sets the phase angle corresponding to the target voltage, the light amount detection means calculates the phase angle based on the amount of light detected each time and the specified amount of light,
4. The exposure apparatus according to claim 3, further comprising fourth phase angle control means for controlling the light source to the prescribed light amount using the obtained phase angle.