JP2666328B2 - Copier - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine capable of making a copy from a document having a relatively large size.

2. Description of the Related Art An electrophotographic copying machine is configured to form an electrostatic latent image by exposing a document and irradiating a light image of the document onto a photosensitive member. This electrostatic latent image is developed with toner to create toner.
The toner image is transferred onto copy paper and fixed to complete a target copy image.

The photoreceptors used in such a copying machine are roughly classified into a drum type and a belt type. In the latter type, the photosensitive member is formed in the shape of an endless belt, so that a part thereof can be kept flat. Therefore, if an exposure operation is performed on this planar portion as if the exposure was performed by a lens shutter type camera, an electrostatic latent image can be instantaneously formed. A copier using this principle is to use a flash lamp for exposure to form an electrostatic latent image in an instant.

However, such a flash lamp exposure type copying machine requires a device for performing exposure with high power and a device for rotating and driving the photoconductor of the endless belt. There is a problem that the device becomes large and the cost increases. Therefore, at present, such an exposure system is employed only in some high-speed copying machines.

On the other hand, a copying machine using a photosensitive drum scans an original and slit-exposes a light image decomposed into a belt shape on the photosensitive drum. Therefore, the photoconductor can be designed to be very compact.

However, in a copying machine using this photosensitive drum, the above-described slit exposure is required to irradiate a light image onto the surface of the photosensitive member that is curved into a curved surface. Therefore,
It is necessary to move the platen glass on which the document is placed in a predetermined direction, or move the document in the opposite direction, to decompose the image into a linear shape. Since such exposure scanning is required, there is a problem that the size of the platen glass increases in a copying machine capable of copying a large-sized document, and the time required for scanning increases.

For this reason, some copying machines employ a scanning method called a so-called short scan.

FIG. 13 explains this. It is assumed that the size of the platen glass 11 on which a document is placed in this copying machine is slightly larger than, for example, A3 size. When making a copy using an A4 size document 12 that is half the size of an A3 size document or a document smaller than this size, the scanning length (scanning length) L1 of the A4 size document 12 is equivalent to L1. Scanning of the platen glass 11 is performed by the width. In other cases, the platen glass 11 is scanned with a width corresponding to the entire scan length L2 to cover the entire area of the platen glass 11.

With such a two-stage scanning method, the length of scanning a relatively small document is reduced, and the time required for scanning such a document is saved.

"Problems to be Solved by the Invention" By the way, recently, the main body of a copying machine can be designed to be relatively compact by downsizing the photosensitive drum and the optical system. Along with this, a copying machine that can copy a document of a larger size with a volume substantially equal to that of the related art has appeared. As a result, various types of originals are mounted on the same platen glass from a relatively small size original to a relatively large size original, and the ratio of the length required for scanning the original is increased. It has become. For example, in a copier equipped with platen glass for copying A2 size originals,
In spite of handling many small documents of A4 size or B4 size or less in a normal office, it is possible to switch between scanning the entire area of A2 size documents and scanning a predetermined length less than that. However, as a whole, a sufficiently efficient scan cannot be realized.

Of course, it is possible to set the scan lengths corresponding to the originals of various sizes with respect to the scan width of the full width, and to switch these to achieve the overall efficiency.
However, in this case, there are disadvantages in that the operator's work such as selecting which scan length is complicated and control for realizing various scan lengths is complicated. Also, if the copying machine attempts to determine the scan length of the document, there is a problem that the circuit device for this is complicated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a copying machine which does not require an operator to specify the size of a document and does not need to determine the size of the document on the apparatus side, and can perform efficient scanning.

[Means for Solving the Problems] In the present invention, as shown in principle in FIG. 1, a platen glass 21, a scanning mechanism 22 for scanning an exposure area on the platen glass 21, and a platen glass 21 Reduction ratio setting means 23 for setting the ratio between the original to be placed and the size of the copy image to be copied on the copy paper; and this reduction ratio setting means 23,
The scanning mechanism 22 scans over the entire area of the platen glass 21 when the magnification is set to be equal to or less than a predetermined magnification determined by a ratio between the maximum size of the readable original and the maximum size of the copy paper for copying the original of the maximum size. First scanning range instructing means 24 for instructing, a photosensitive member 25 for forming an electrostatic latent image corresponding to an image of a document placed on the platen glass 21 by scanning of the scanning mechanism 22, and Copy paper transport means 27 for transporting the copy paper to the transfer position P1 of the photoconductor 25 at the same speed as the moving speed of the photoconductor surface in order to transfer the toner image formed on the photoconductor 25, and transported by the copy paper transport means 27 The copy paper to be transported from the transfer position P1 to the transfer position by the copy paper transport means 27 is longer than the distance from the exposure start point on the photoconductor to the transfer position P1. At this timing, when passing the specific position P2 where the distance on the road is shorter, the scanning mechanism
A second scanning range instructing means for instructing to end scanning of the platen glass 21 by 22 and to return to a scanning start position;
And a scanning range control means 29 for controlling the scanning range of the scanning mechanism 22 by selecting the narrower one of the instructions of the first and second scanning range instructing means 24 and 28.

That is, in the present invention, when the reduction ratio is set to a certain value or less by the reduction ratio setting unit 23, the original size is determined to be large, and the scanning of the entire width of the platen glass 21 is instructed by the first scanning range instruction unit 24. . In addition, the second scanning range instructing means 28 knows an originally unnecessary scanning section from the relationship with the copy paper conveyed in synchronization with the scanning of the original, and finally determines the scanning range by the scanning range control means 29. Identify. This allows efficient scan length control from a viewpoint different from control of the scan length based on the size of the document.

"Example" Hereinafter, the present invention will be described in detail with reference to examples.

"Table of Contents" First, a table of contents in the description of the copying machine of this embodiment is shown.

(1) Overview of Copying Machine (2) Overview of Rotating Configuration of Copying Machine (3) Console Panel (4) Specific Circuit Configuration (4-1) Photoconductor Drum Periphery (4-2) Optical System (4-3) ) Fixing device (4-4) Billing counter (4-5) Power supply (5) Control of scan length of platen glass (5-1) Actual control of scan length (5-2) Limit of scan length by sensor (5) -3) Control of Scan Length (1) Outline of Copying Machine FIG. 2 shows the appearance of the copying machine of this embodiment. The main body of the copying machine 31 discharges a copying machine main body 33 mounted on a dedicated cabinet 32, three types of cassette trays 34 to 36 removably arranged in the copying machine main body 33, and copy paper. And a discharge tray 37. An openable and closable platen cover 38 is attached to an upper portion of the copying machine main body 33, and a platen glass, which is not shown in the drawing but is not shown in the drawing, is disposed below the platen cover 38. Since this copier can copy up to A2 size originals according to Japanese Industrial Standards, the platen glass is slightly larger than the area of this largest original.

In front of the platen cover 38 on the upper surface of the copying machine body 33, a console panel 39 is arranged. As will be described in detail later, the console panel 39 incorporates a liquid crystal display panel together with various key switches for input. The LCD panel displays the number of copies and jams (paper jam).
Etc. are displayed.

A manual feed tray 41 is attached to the right side of the copying machine main body 33 in the drawing. When performing the manual feed, the manual feed tray 41 is tilted down, and the copy paper is manually fed from here. In this copier, in addition to the manual feed tray 41,
Since the cassette trays 34 to 36 are prepared, copy paper can be supplied by four systems. In this case, the maximum size of copy sheets that can be set in the cassette trays 34 to 36 is A3 size. Similarly, the size of copy paper that can be manually fed from the manual feed tray 41 is set so that the A3 size is maximized.

FIG. 3 shows an outline of the internal structure of the copying machine. A platen glass 51 for placing a document (not shown) is placed on the upper part of the copying machine body 33. Immediately below the platen glass 51, a light source consisting of a halogen lamp
52 is reciprocated by a carriage (not shown), so that exposure scanning of the document is performed. Light rays reflected from the strip-shaped exposure area are first to third rays.
After being reflected by the mirrors 53 to 55, the light enters the optical lens 56. The light beam passing through the optical lens 56 is reflected by the fourth mirror 57,
Irradiated at 59.

The photoreceptor drum 58 is rotated at a constant speed in the direction of an arrow (clockwise) by a main motor described later, and the surface thereof is uniformly charged by the action of the charge corotron 61. When the charged portion reaches the exposure position 59, the portion is irradiated with the reflected light of the original and is selectively discharged to form an electrostatic latent image. This electrostatic latent image is
After an unnecessary portion is removed by the inter-image lamp 62, the image is developed by the document device 63 to form a toner image. This toner image is transferred to a copy sheet (not shown) by the action of the transfer corotron 64 and the detack corotron 65. At this time, the toner remaining on the photosensitive drum 58 is a pre-clean corotron.
After being neutralized by 66, it is scraped off from the drum surface by a doctor blade 67. When the cleaning of the photosensitive drum 58 is completed in this way, the surface of the drum is charged again by the charge corotron 61 to prepare for the next exposure operation.

By the way, as described above, this copying machine is provided with four paper feeding mechanisms. Three cassette trays 34
One size sensor 71 is arranged in front of each of the storage positions into which the to 36 are to be inserted, so as to determine the size of the copy sheets stored in these trays. There are various methods for this determination. In the copying machine of the present embodiment, irregularities specific to the paper size are provided at the leading ends of the respective cassette trays 34 to 36, and the irregularities are detected by the size sensor 71, and the respective resistors of a circuit in which a plurality of resistors are connected in parallel are provided. Set each switch connected in series to ON or OFF. As a result, a resistance value corresponding to the detected size of the copy sheet is output as analog data. A CPU (central processing unit) described later inputs this analog data and determines the size of the copy sheet.

In the vicinity of each size sensor 71, a paperless sensor 72 is arranged. Feed rollers 73 are arranged above the front portions of the cassette trays 34 to 36, respectively. The feed roller 73 is used to feed copy paper from a tray selected from the cassette trays 34 to 36.
The no-paper sensor 72 is a sensor for detecting that the copy paper in the cassette tray has run out when the feed roller 73 does not feed the copy paper.

On the other hand, the manual feed tray 41 is also provided with a feed roller 73 at the tip thereof, so that the manually inserted copy paper is fed into the copying machine main body at a predetermined timing. The manual sensor 75 is a sensor for detecting that manual feeding has been performed. On the condition that the manual sensor 75 detects the copy sheet for one second or longer, it is recognized that the copy sheet is set on the CPU manual feed tray 41. This is to prevent the copying operation from being started in such a case because the operator may immediately pull out the copy sheet without manually inserting it.

The manual solenoid 76 is used for gate control for controlling start of feeding of copy paper. The manual solenoid 76 is located at a position where the copy sheet is prevented from passing, and the gate is opened when the copy cycle starts. As a result, the driving force is transmitted to the feed roller 73 of the manual feed tray, and the feeding of the copy sheet is started.

Copy papers selectively fed from these four paper supply mechanisms travel along a transport path 77 shown by broken lines in the figure. Then, the arrival of a copy sheet is detected by a feed sensor 78 arranged at a place where these transport paths 77 are integrated. Conveyance of the copy sheet is not always started accurately due to slippage of the feed roller 73 or the like. Therefore, the conveyance of the copy sheet 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 starts to be conveyed, passes between the photosensitive drum 58 and the detack corotron 65, and receives the transfer of the toner image. The copy paper on which the toner image has been transferred is conveyed by a conveyance belt 81, and is a pressure roller as a heat roll 82 provided at an exit side thereof.
Pass between 83. The heat roll 82 is heated by a built-in quartz lamp, where the toner image is heated and fixed on copy paper. The copy paper on which the fixing has been completed is discharged to a discharge tray 37 by a discharge roll (not shown).
Is discharged on top.

Note that the three cassette trays 34 to 36 used in this embodiment do not necessarily need to accommodate copy paper of different sizes. For example, a tray that stores copy paper of the same size may be used as the two cassette trays 34 and 35. In this case, when there is no more copy paper in the selected cassette tray, the other cassette tray is automatically selected and the copy paper is continuously fed.

In this copier, the registration gate (registration gate) is released by demagnetizing the registration gate solenoid.
Although the 79 is opened, when the register gate 79 is closed, the solenoid is energized.
Therefore, there is an advantage that the position fluctuation of the registration gate 79 in a state where the passage of the copy sheet is blocked is reduced, and the leading end of the copy sheet can be accurately positioned.

(2) Outline of Circuit Configuration of Copying Machine FIG. 4 shows a main part of the circuit configuration of the copying machine, focusing on a CPU (central processing unit). This CPU 91
D converter, USART (Universal Synchronous / Asynchro
It has functions such as a nous receiver (transmitter), a timer / counter, and an input / output port, and is connected to the following units via a bus 92 or a terminal 93 for analog input.

(B) Those connected via the bus 92.

(I) ROM 94: a read-only memory that stores various programs of the copying machine, and has a capacity of 32 Kbytes in this embodiment.

(Ii) RAM95: Random access memory for temporarily storing various data
This is a memory, and has a capacity of 2 Kbytes in this embodiment.

(Iii) Non-volatile memory 96: This is a random access memory that is backed up by a battery (not shown) and stores data that should not be erased even when the copier is turned off. Such data includes, for example, (a) a setup value for adjusting registration of copy paper, and (b)
A set value of the amount of erase at the front end of the image by the inter-image lamp 62 (FIG. 3); (c) a fine adjustment value of the vertical and horizontal magnifications when the copy magnification is set to 1: 1;
(D) Adjustment values of various parameters performed in the production line of the copying machine, (e) history data recording the situation such as jam of the copying machine, (f) designation data of a cassette tray used preferentially, and the like. be able to.

(Iv) Keyboard / display LSI 97: A large-scale integrated circuit provided on the console panel 39. This will be described later in detail.

(V) Timer / counter LSI 98: a large-scale integrated circuit for setting timing for controlling the driving of the main motor 101 and the carriage motor 102. Here, the main motor 102 is a motor used for driving the photosensitive drum 58, the transport belt 81, the heat roll 82 and the like shown in FIG. The carriage motor 102 is a drive source for reciprocating a carriage (not shown) for scanning the light source 52, the optical lens 56, and the like also shown in FIG.

(Vi) I / O controller 103: an input / output controller that inputs various digital data via a filter circuit 104 and controls driving of various components via a driver circuit 105. Here, for example, various switches and sensors are connected to the filter circuit 104. The driver circuit 105 is connected to a clutch (not shown) for controlling the driving of the four feed rollers 73 shown in FIG.

(B) The one connected to the CPU 91 via the analog input terminal 93.

(I) Light amount sensor 107: In this copying machine, a monitor lamp (not shown) for monitoring the light amount is arranged in parallel with the light source 52. The intensity of the light amount of the monitor lamp is detected by the light amount sensor 107, and is input as analog data from the terminal 93 to the CPU 91 and processed.

(Ii) Temperature sensor group 108: This copying machine is provided with a soft touch sensor (see FIG. 8) which comes into light contact with the roll surface to detect the surface temperature of the heat roll 82 shown in FIG. Have been.
Analog data output from such sensors is input to the terminal 93 in the same manner.

(Iii) Size sensor group 71: A group of sensors for detecting the size of the copy sheet stored in each of the cassette trays 34 to 36 shown in FIG.
In this copier, cassette trays for individually storing copy paper of the following six fixed sizes are prepared as standard specifications. Of course, a cassette tray of a foreign specification such as legal size can also be used.

(A) Japanese Industrial Standard B5 size paper horizontal feed (b) Japanese Industrial Standard B5 size paper vertical feed (c) Japanese Industrial Standard A4 size paper horizontal feed (d) Japanese Industrial Standard A4 size paper vertical feed (e) Japanese Industrial Standard A3 size paper horizontal feed (f) Japanese Industrial Standard A3 size paper vertical feed Since many types of cassette trays are selected and used as described above, four sensors are arranged on each cassette tray to discriminate these. When the conventional data processing method is used, the CPU 91 needs a maximum of 12 input ports. In addition to this, the number of connectors and the number of cables constituting the harness are increased, which causes a problem in terms of cost, miniaturization, and reliability requirements of the device.

Therefore, in the copying machine of the present embodiment, as described above, the size sensor 71 composed of the resistor and the switch is prepared at each storage location of the cassette tray, and the data of the combined resistance value according to the on / off state of each switch is converted into analog data by the CPU 91.
To send to. This allows the maximum type of cassette tray
You can identify up to 16 types.

(C) Others The reset circuit 109 is connected to the reset terminal 111 of the CPU 91. The reset circuit 109 supplies a reset signal to the CPU 91 at the time of runaway or initialization of the CPU 91 to reset it.

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

A menu display panel 121 is provided above the console panel 39, for example.
Are arranged, and the contents of each panel portion are displayed in characters. Hereinafter, these panel portions will be described in order.

(B) A2 document mode: This copier can copy up to A2 size documents. However, since copy paper up to A3 size can be used, when an A2 size document is used, the image information of the entire document cannot be reproduced unless the document is reduced. When the A2 document mode button 123 is pressed, the two display lamps 124 disposed thereon are turned on one by one, and one of the two modes is selected. Here "A2
When the display lamp 124 of the item marked `` → A4 '' lights up,
The tray containing the A4 size copy paper is selected from the cassette trays 34 to 36, the reduction ratio is set to 50%, and the copying operation from A2 size to A4 size is selected.
On the other hand, the display lamp of the item marked “A2 → A3”
When 124 lights up, the tray containing the A3-size copy paper is selected from the cassette trays 34 to 36, and the reduction ratio is set to 70%, and the copy work from A2 to A3 is selected. Will be done.

Of course, if the operator does not press the A2 document mode button 123, for example, sets the magnification to 70% and selects the cassette tray of A3 size, the same copying operation as "A2 → A3" is executed. be able to. The panel portion of the “A2 original mode” is provided for the purpose of performing such operations more easily and without errors.

(B) Document size: When the document size button 125 is pressed, the four display lamps 126 arranged in a row next to this light up one by one,
Originals from the A3 size to the A3 size are sequentially selected. As will be described later, in this apparatus, the size of the copy paper is also selected, and when both are selected, the reduction ratio is automatically calculated and set based on these relations. ing.

(C) Reduction / Enlargement: In this column, a magnification display section 128 for displaying a reduction magnification from 50% to 200% in increments of 1% is provided. Designation of the reduction ratio can be performed by operating two arbitrary% designation keys 129 or a fixed size designation key 131 arranged below the magnification display section 128.

When the upper key of the arbitrary% designation keys 129 is pressed, the magnification is increased by 1% up to a maximum of 200%. Pressing a key located at the bottom lowers the magnification by 1% to at least 50%.

On the fixed size designation key 131, four display lamps 132
Is arranged. These are for displaying fixed magnifications of 100%, 63%, 121% and 135%, respectively. When the fixed size designation key 131 is pressed, these display lamps 132 are sequentially selected one by one. Note that 1
The three types of magnifications other than 00% 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 cassette trays 3
Three types of display lamps 135 respectively displaying 4 to 36 are sequentially turned on one by one, and the selection status of the tray is displayed. On the left side 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 landscape" is used to indicate that a cassette tray in which A4 or B5 size copy paper has been set in the transverse direction has been selected, and these cassette trays are used. In the rare case, they are displayed in a unified manner. These may be displayed individually depending on the copying machine. Also, “A4 / B
Under “5 horizontal”, an indicator lamp 136 of “non-standard” is provided to standardize that a cassette tray containing copy paper of a size other than these sizes is selected. It is.

(E) Copy density: Two copy density buttons 138 are provided in this column. Above these buttons 134, five types of display lamps 139 each standardizing five levels of copy densities are arranged, and one of them is selectively displayed by button operation, and the copy densities are selected. It has become.

(F) Display / Key Operation In this column, a display unit 141 and an operation unit 142 in which various keys are arranged are arranged.

(A) Display section 141: Display section for displaying the selection status of cassette trays 34 to 36
A display unit 144, a display unit 145 for the number of copies, and a display unit 146 for various situations of the copying machine are arranged. The characters displayed on the display unit 146 include "paper jam", "copy is possible", "please wait", "cassette difference", and the like. These characters are displayed by selectively lighting a light emitting diode provided behind.

The "cassette difference" is a character that may be abnormal in the combination of the size of the document, the size of the copy sheet, and the reduction ratio, and is displayed in a blinking manner when erroneous copying is expected. Copying can be performed even when this display is being performed.

(B) Key operation unit 142: Various keys or buttons as described below are arranged here.

(I) Page continuous shooting button 151: A button for implementing a page continuous shooting function. Here, the continuous page copying function is a function of dividing an original spread over two pages, such as a bound original, into two pages one by one in a spread state and sequentially copying the originals. When the page continuous shooting button 151 is pressed, a display lamp 152 arranged near the button is turned on, indicating that the page continuous shooting function is selected.
When the continuous page function is selected, the reduction ratio is automatically set to 100.
% (Actual magnification), and the cassette tray containing the copy paper of “A4 / B5 landscape” is selected.

(Ii) Program button 153: A button for setting the copier to a mode used when writing various data to the nonvolatile memory 96. Such data includes, for example, three types of cassette trays.
Data for setting the tray (priority tray) to be preferentially selected from 34 to 36 and the power saving function that shuts off part of the power supply when no copying work is performed There is data on the required time. CPU91
When the copier is turned on in the initial state, or when the copier returns to the initial state for any reason, the cassette tray
The data stored in the non-volatile memory 96 is checked for items having preferential handling such as 34 to 36, reduction ratio, etc., and the console panel 39 is displayed accordingly, and the copier is set to the designated state. When the program button 153 is pressed, an indicator lamp arranged near this button
154 lights up to indicate that the mode has been set to perform various settings of the copying machine.

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

(Iv) Numeric keys 157: Numeric keys used to set the number of copies.

(V) Interruption button 158: This button is used to temporarily suspend the currently used copy operation and enable the copy operation under other copy 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 stop copying.

(Vii) Start button 161: A button for starting a copy operation. In the vicinity of the start button 161, a start reservation display lamp 162 is arranged. When the start button 161 is pressed in a state where the character “Please wait” in the display unit 146 is lit, an instruction to start the copying operation is reserved, and the display lamp 162 is lit. In this lit state, the character "wait" in the display unit 146 is turned off, and the copy operation is automatically started when "copying is possible" is displayed instead.

As described above, the console panel 39 is provided with many keys and light-emitting diodes (display lamps). Therefore, if all these components are individually connected to the CPU 91, the number of ports becomes insufficient. Therefore, in this embodiment, a keyboard / display LSI 97 (FIG. 4) is used as this solution. Keyboard display LS
The I97 constantly monitors keystrokes. The information as the monitoring result is converted into 8-bit data in a time-division
To be transmitted. The 8-bit lighting control signal sent from the CPU 91 in a time-sharing manner is transmitted to the number of light-emitting diodes (display lamps 124, 126, 13) arranged on the console panel 39.
(2, 136, 139, 152, 153, etc.), control is performed to keep these light emitting diodes on or off.

(4) Specific Circuit Configuration Next, a specific circuit configuration of the copying machine will be described.

(4-1) Around the Photoconductor Drum As shown in FIG. 3, components such as the charge corotron 61 are arranged around the photoconductor drum 58. Since these have already been described in general terms, only the inter-image lamp 62 and components not described above will be described here.

(A) Inter-image lamp: FIG. 6 shows the structure of an inter-image lamp. The inter-image lamp 62 is composed of 80 light emitting diodes 221 arranged in a line, and one plastic lens 222 arranged on the front surface thereof. The plastic lens 222 has an aspherical convex portion at a position corresponding to each light emitting diode.
Even when the portions 1 emit light adjacent to each other, care is taken so that the light does not have an uneven intensity on the photosensitive drum 58 (FIG. 3) even in the boundary region therefrom.

The 80 light emitting diodes 221 are turned on / off at predetermined intervals by a 5-bit signal output from the CPU 91. At this time, the left and right 30 light emitting diodes 221 are turned on and off in the same signal state at the left and right symmetric positions.
The off control is performed, and the central 20 light emitting diodes 221 are simultaneously controlled on and off with the same signal state. For this reason, the 80 light emitting diodes are controlled to be turned on / off by 31 kinds of control signals in terms of control, and control by 5-bit data becomes possible as described above.

(B) Toner sensor: A sensor (not shown) for determining whether toner supply is necessary in the developing device 63.

(C) Dependence motor: The developing device 63 is provided with a toner box (not shown) for storing toner. A motor (not shown) is used to agitate and reinforce the toner in the toner box. Similarly, when an increase switch (not shown) is pressed, the dispense motor is forcibly driven, and the amount of toner is increased.

(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 portion (solid black portion) of the document. .

(E) Full toner sensor: A sensor (not shown) for detecting whether the used toner is collected by the doctor blade 67 and the toner is sufficiently collected in the collection container.

(4-2) Optical System FIG. 7 shows a circuit portion related to the optical system. This copier can scan a document of a maximum A2 size. Therefore, the tube length of the halogen lamp constituting the light source 52 is set to be slightly longer than the length of the A2-size document in the width direction. Light source 52
Is reciprocated a little longer than the longitudinal direction of an A2-size document with the movement of the carriage driven by 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. 4 and a clock output from a one-shot multivibrator that frequency-voltage-converts an encoder output (not shown). You. The start and stop of the rotation of the motor and the rotation direction are controlled by the start signal and the rotation direction instruction signal output from the I / O controller 103 also shown in FIG. All of these clocks and signals are controlled by the peripheral
Since the signal is output from the SI, the drive control of the carriage motor 102 may be substantially performed by the CPU 91.

The registration sensor 251 is a sensor used for detecting the scanning position of the carriage. That is, the 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 positioned near the scanning start position,
An actuator (not shown) attached thereto turns on / off this sensor. Registration sensor 25
This detection output of 1 is taken into the CPU 91, and timing control for determining the transfer start time of the copy sheet, the scan length of the carriage, and the like is performed based on this timing.

Lens mirror sensor 253 is optical lens 56 and mirror 5
3 (FIG. 3) and the like that perform movement control, but are constituted by one detection element. Lens mirror motor
Reference numeral 254 also changes the type in which the optical lens 56 and the mirror 53 and the like are separately driven in the conventional copying machine to a type that can be commonly driven. The optical system fan 255 is a fan for removing the heat of the platen glass 51 by air cooling the optical system part.

The light source 52 and the optical system fan 255 are driven by an AC (alternating current) driver 257 of the copying machine. In addition, 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 driven by a DC (direct current) power supply.

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

The fuser lamp 261 is disposed in the heat roll 82 (FIG. 3), and its control is performed by a fixing control element (SSR) 262. The surface temperature of the heat roll 82 is detected by the soft touch sensor 263, and the temperature information is transmitted to the CPU 91. The fuser outlet sensor 264 is an element for detecting that the copy sheet that has passed between the heat roll 82 and the pressure roller 83 is discharged toward the sheet discharge tray 37 without being erroneously entangled between them. The fixing control element (SSR) 262 is driven by the AC driver 257, and the soft touch sensor 263 and the fuser exit sensor 264
Driven by DC power supply 258.

(4-4) Billing Counter As shown in FIG. 8, this copying machine has a billing counter.
271 are provided. The billing counter 271 is a counter used for collecting a copy fee, and counts the total number of copies.

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

The copying machine body 33 is connected to a commercial power supply of 100 V (volt). 115V60Hz and 220V50Hz for overseas use
It can also handle power supplies. Outlet 28
The power supplied from 1 is supplied to the main switch 284 via a 15-amp circuit breaker 282 and a noise filter 283.
To reach. The output side of the main switch 284 is supplied as power to the AC driver 257, the fixing control intention 262, and the DC power supply 258 via the interlock switch 285.

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

(A) Light source 52 and fan 255 for optical system (FIG. 7) (B) Fuser lamp 261 (FIG. 8) DC power supply 258 supplies power to the following parts at predetermined timings. Lock switch 285 (FIG. 8) (b) AC dryer 257 (FIG. 8) (c) High voltage power supply (d) Fuser outlet sensor 264 (FIG. 8) (e) Fixing control element 262 (FIG. 8) (F) Accessory 286 (FIG. 8); Here, the accessory 286 is, for example, a coin kit capable of copying using a coin, a key counter or a key coder for managing copy of each department. Exists.

(G) Billing counter 271 (FIG. 8) (H) X-port fan 287 (FIG. 8); This fan is a vacuum fan for sucking copy paper conveyed along a conveyance path called X-port.

(I) Inter-image lamp 62 (FIG. 3) (N) Carriage motor 102 (FIG. 7) (R) Registration sensor 251, lens mirror sensor 253, and lens mirror motor 254 (FIG. 7) Increment switch (5) Control of scan length of platen glass (5-1) Actual control of scan length Table 1 below shows the actual control of scan length of the copying machine of this embodiment. .

(A) First, when the same magnification is selected as the reduction ratio, the scan length is set according to the type of each document. This copier uses an A2-size original, but since it is assumed that the original is reduced to a predetermined size of A3-size or smaller, the control of the scan length at the same magnification is not applicable.

(B) When enlargement is designated as the reduction ratio, control is performed when the document is not larger than the A3 size.
The larger the enlargement ratio, the smaller the size of the document to be copied on the maximum A3-size copy paper, so the scan length changes according to the magnification as shown in this table.

(C) There are three cases where reduction is designated as the reduction ratio.

In the first case, the copy condition is set with priority on the reduction ratio by operating the arbitrary% designation key 129 or the fixed size designation key 131 shown in FIG. This copier can utilize the so-called zoom (ZOOM) function of continuously changing the reduction ratio in 1% steps by controlling the positional relationship of the optical lens 56, the mirror 53, and the like. When the reduction ratio is specified, the control differs depending on whether the reduction ratio is 70% or less.

That is, when the reduction ratio is 70%, when the A2 size original 291 is placed on the platen glass 51 as shown in FIG. 9, this is reduced to the A3 size. Thus, in this case, it is considered that a large subcutaneous document is often used. Therefore, the scanning is set to be performed over the entire width of the platen glass 51. In this copying machine, since the photosensitive drum 58 rotates at a constant speed, the moving speed of the scanner differs depending on the reduction ratio, and the time required for scanning also changes as shown in this table.

The second case is when an A2 size original is used. In this case, of course, scanning is performed over the entire width of the platen glass 51. However, since the scanning speed is different when the reduction ratio is different as described above, the time required for scanning differs between when the size is reduced to A3 size and when the size is reduced to A4 size.

The third case is a case where the reduction ratio is set from the relationship between the size of the document and the copy sheet. In this case, the size of the document is designated by pressing the document size button 125 shown in FIG. The size of the original specified at this time is A3
Since the format is the largest, the scan length is set to 425 mm correspondingly.

In some cases, the reduction ratio is set to 100% as a result of specifying the reduction ratio or determining the size relationship between the original and the copy sheet. In this case, the control is performed in the same size as described in (a) above. It is time control.

(D) Even in each of the above cases, when the rear end of the copy sheet is detected by the feed sensor 78 (FIG. 3),
If more than 1 second has passed since the start of scanning,
At that point, scanning stops and reverse starts. That is, if this condition is satisfied, scanning is performed with a scan length shorter than the scan length described in the table.

(E) In this copying machine, three types of cassette trays 34 to 36
In addition, copy paper can be fed from the manual feed tray 41. Copy papers of various sizes can be fed from the manual feed tray 41. In this case, the same scan length control as when the above-described zoom function is utilized is performed. When feeding nonstandard size paper such as legal size copy paper, the same control as when copy paper is fed from the manual feed tray 41 is performed.

(5-2) Restriction of Scan Length by Sensor As described above, in this copying machine, the rear end of the copy sheet is detected by using the feed sensor 78, and the scanning of the scanner is returned at that time.

FIG. 10 shows the relationship between the photosensitive drum and copy paper.

Now, it is assumed that the upper right point in the drawing of the photosensitive drum 58 is the exposure position 59. It is also assumed that the transfer position 301 exists near the lowermost portion of the photosensitive drum 58. In this case, when the drum portion corresponding to the exposure position 59 has just moved to the transfer position, the corresponding image is copied to the copy paper.
It will be transferred to 302. The transfer position 301 and the feed sensor 7 arranged in the middle of the conveyance path of the copy paper 302
The distance to 8 is L1. A distance L2 connecting the two positions 59 and 301 along the surface of the photosensitive drum 58 is defined as L2. The feed sensor 78 is also a sensor for checking the conveyance state of the copy sheet 302, but is also used in this embodiment for controlling the scan length of the scanner as described above. Because of this, the distance
The position of the feed sensor 78 is set so that L1 and L2 satisfy the following equation (1).

L1 <L2 (1) Since the peripheral speed of the photosensitive drum 58 and the conveyance speed of the copy sheet 302 are the same, if the distances L1 and L2 are set as shown in the equation (1), the document will reach the rear end of the copy sheet 302. A toner image corresponding to the image information is secured. That is, even if the exposure scanning is terminated when the feed sensor 78 detects the trailing edge of the copy sheet 302, this completely covers the image to be copied.

For the above reasons, an instruction is given at the time when the scanning by the scanner is completed. CPU 91 shown in FIG.
Means that the scan length is selected by selecting the scan length shorter than the scan length shown in Table 1 and this instruction.

(5-3) Control of Scan Length FIG. 11 shows control for setting the scan length in the standby state of the copying machine.

The CPU 91 monitors whether the reduction ratio is changed (step). When the reduction ratio is changed, the optical system such as the optical lens 56 is moved (step). Then, in this state, it is determined whether or not the original size is designated by the original size button 125 (FIG. 5) (step). If the size of the document has been designated, the scan length is set to the length of the A3 size only when this is a designation for reduction (step).

On the other hand, if the original size is not specified by the original size button 125 (step; N), it is determined whether the reduction ratio is 70% or less (step;
; Y). If it is 70% or less (Y), the scan length is set to the entire width of the platen glass 51, that is, the A2 size (step).

If it is not less than 70% (N), it is determined whether it is equal to 10% or equal (step). If the reduction ratio is 100% (Y), the scan length is set to the length of the copy sheet (step). If it is not 100% (N), the scan length is set according to the reduction ratio (step). A table (not shown) showing the relationship between the reduction ratio and the scan length is shown in the ROM 94 shown in FIG.
Is stored in

FIG. 12 shows the control of the scan length after the start button is pressed to start the copying operation.

First, the carriage motor 102 shown in FIG. 7 is driven, and the scanner containing the optical lens 56 and the like starts the forward movement from the left end of the platen glass 51 shown in FIG. 9 (step). The CPU 91 monitors the timing at which the movement of the scanner is detected by the registration sensor 251 (see FIG. 7) (step). When the detection of the registration sensor 311 is performed (Y), the counting operation of the timer for controlling the scan length starts (step). This timer can be realized by sequentially updating numerical values to be written in the RAM 95 shown in FIG. This timer has
The numerical value corresponding to the scan length set in FIG. 11 is written.

In this state, the CPU 91 monitors whether the timer times out (step) or whether the feed sensor 78 detects the trailing edge of the copy sheet and turns off (step). Then, at the timing when any of these is realized, the moving direction of the scanner is reversed, and the reverse is started (step). That is, the scan length is thus determined under the condition that the scan length is shorter than the two conditions.

In the embodiment described above, the photosensitive drum is used as the photosensitive member. However, it is obvious that the present invention can be similarly applied to other photosensitive members such as a belt-shaped photosensitive member.

[Effect of the Invention] As described above, according to the present invention, it is determined whether or not the magnification is set to be equal to or less than a predetermined magnification determined by a ratio of the maximum size of the original and the maximum size of the copy paper for copying the original of the maximum size. The first scanning range instructing means instructs the scanning mechanism to scan over the entire area of the platen glass, and when the copy sheet passes a specific position on the transport path, the second scanning range instructing means causes the platen by the scanning mechanism to be timed by the scanning mechanism. The scan length is instructed to return to the scanning start position where the scanning of the glass has been completed, and the scan length is set by both instructions, so that the scan length can be set efficiently without detecting the size of the document. it can. That is, even in a copying machine that does not include a mechanism for detecting the size of a document, the copying operation can be speeded up by setting the scan length efficiently. Further, the scan length can be set efficiently even for copy sheets other than the standard size.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the principle of the present invention, and FIGS.
FIG. 2 is a view for explaining one embodiment of the present invention. FIG. 2 is a perspective view showing the appearance of a copying machine, FIG. 3 is a schematic configuration diagram showing an outline of the internal structure of the copying machine, and FIG. 4 is a block diagram showing a main part of a circuit configuration of the copying machine, FIG. 5 is a plan view of a console panel, FIG. 6 is an explanatory view showing a configuration of an inter-image lamp, and FIG. 7 is an optical system of the copying machine. FIG. 8 is a block diagram illustrating a circuit configuration of a fixing device and a power supply unit, FIG. 9 is an explanatory diagram illustrating a relationship between a platen glass and a scan length and a reduction ratio, and FIG. FIG. 11 is an explanatory diagram showing the relationship between the body drum and the conveyance timing of copy paper, FIG. 11 is a flowchart showing control for setting a scan length in a standby state of the copying machine, and FIG. 12 is a copy when a start button is pressed when a start button is pressed. Scan after work started Flow chart showing the control of the
FIG. 13 is an explanatory view showing a conventional scanning method called a short scan. 21: platen glass, 22: scanning mechanism, 23: reduction ratio setting means, 24: first scanning range designating means, 25: photoreceptor, 27: copy paper conveying means, 28: second Scanning range indicating means, 34 to 36 ... cassette tray, 39 ... console panel, 51 ... platen glass, 78 ... feed sensor, 91 ... CPU, 94 ... ROM, 95 ... RAM, 251 ... Cash register sensor.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-56-154748 (JP, A) JP-A-52-5529 (JP, A) JP-A-58-217948 (JP, A) JP-A 55-154 25087 (JP, A) JP-A-53-107849 (JP, A) JP-A-1-150175 (JP, A) JP-A-1-116568 (JP, A) JP-A-60-247635 (JP, A) JP-A-59-49526 (JP, A) JP-A-60-39037 (JP, U) JP-A-61-188139 (JP, U)

Claims (1)

(57) [Claims] 1. A platen glass, a scanning mechanism for scanning an exposure area on the platen glass, and a ratio between a document placed on the platen glass and a size of a copy copied on copy paper are set. Reduction ratio setting means, and when the reduction ratio setting means is set to be equal to or smaller than a predetermined magnification determined by a ratio of a maximum size of a readable original to a maximum size of copy paper for copying the original of the maximum size. First scanning range instructing means for instructing the scanning mechanism to scan over the entire area of the platen glass; and an electrostatic latent image corresponding to an image of a document placed on the platen glass by scanning of the scanning mechanism. The photoconductor to be formed and the copy paper are conveyed to the transfer position of the photoconductor at the same speed as the moving speed of the photoconductor surface in order to transfer the toner image formed on the photoconductor. Copy paper transport means, and the copy paper transported by the copy paper transport means is transported from the transfer position to the transfer position by the copy paper transport means from the transfer position to the transfer position with respect to the distance from the exposure start point on the photoconductor to the transfer position. A second scanning range for instructing the scanning mechanism to terminate scanning of the platen glass and return to the scanning start position at this timing when the copy paper to be copied has passed a specific position where the distance on the transport path is shorter. A copying device comprising: an instruction unit; and a scanning range control unit that selects a narrower scanning range among the instructions of the first and second scanning range instruction units and controls a scanning range of the scanning mechanism. Machine.