JPH0218576A - Copying machine - Google Patents

Abstract

PURPOSE:To speed up copying operation by providing a normal mode wherein the copying operation is performed under optionally set copying conditions after the electrostatic charging state of a photosensitive drum is stabilized and a standard copying mode wherein the copying operation is performed immediately under standard copying conditions. CONSTITUTION:When plural-sheet continuous copying operation is carried out under optionally set copying conditions, the operation is performed in the normal mode. Namely, a photosensitive drum 6 idles specific times with a print switch to repeat electrostatic charging and erasing operation until the electrostatic charging state becomes stable and then the copying operation is started to take a copy of uniform picture quality. Under the standard copying conditions wherein only one copy is taken, on the other hand, the copy is obtained speedily by starting the copying operation in the standard mode, i.e. without making the drum 6 idle. Consequently, only one copy is taken, so the uniformity of the picture quality is not important.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a copying apparatus, and particularly to a copying apparatus that can quickly copy only one sheet.

(Prior Art) When multiple sheets are continuously copied in an electrophotographic copying device, especially a high-speed, large-volume copying device, although high-speed processing is performed, it takes time for the charged state of the photoreceptor drum to stabilize. Therefore, there will be a change in image quality between the first and second copies, or between copies up to about the 10th copy. To prevent this, in conventional high-speed copying machines, until the charged state of the photoreceptor drum stabilizes,
Charge and erase while rotating the photoconductor drum 2~
After repeating the process about three times, the copying operation is started.

(Problem to be solved by the invention) However, when idling as described above, for example, 5
Even with high-speed copying machines capable of copying at a rate of 0 sheets per minute or more, the user must wait more than 4 seconds before making the first copy. However, when copying only one sheet, there is a problem in that it is very inconvenient to have to wait for more than four seconds even though it is a high-speed copying apparatus.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, it is an object of the present invention to provide a copying apparatus that can quickly copy only one sheet.

(Means for Solving the Problems) In order to achieve the above object, the present invention stabilizes the charged state of the photoreceptor drum by repeating charging and erasing by idling the photoreceptor drum under arbitrarily set copying conditions. Normal mode starts the copying operation after copying, and when the number of copies is 1
The present invention is characterized in that it includes a standard mode in which a copying operation is immediately started without idle rotation under standard copying conditions that include at least a condition of copying.

(Function) Since the present invention has the above configuration, under arbitrarily set copying conditions such as when continuously copying multiple sheets, copying is performed in the normal mode, and the photosensitive drum idles and charges and erases repeatedly. After the charging state is stabilized, the copying operation is started, and copies with uniform image quality can be obtained. On the other hand, when copying only one sheet, by copying in the standard mode, the copying operation is started without idle rotation of the photoreceptor drum, and the copy can be obtained quickly.
Since it is a single copy, there is no need to worry about differences in image quality.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 7.

FIG. 2 shows a slit scanning type electrophotographic reproduction apparatus. Second
In the figure, an original M placed on a glass plate 1a of an original platen 1 is irradiated with an exposure lamp 2, and image light from the original M passes through a slit 3, and is transmitted through an imaging lens 4 and a plurality of mirrors 5a. Through the imaging optical system I consisting of ~5d etc.,
The image is projected onto the photosensitive drum 6, which is rotated counterclockwise in the figure at a constant circumferential speed of ■.

The exposure lamp 2, slit 3, and first mirror 5a that constitute the scanning device S scan the original M by moving to the left in the figure at a speed of V/n (where n is the copying magnification). Also, the second
The mirror 5b and the third mirror 5C are used to maintain a constant imaging optical path length by the imaging optical system I.
It moves to the left in the figure at a speed V/2n, which is half the moving speed V/n of .

The image light scanned by the scanning device S forms an image on the photoreceptor drum 6, and the negative charge on the surface is selectively annihilated depending on the brightness of the image light.
An electrostatic latent image of this image light is formed.

Around the photosensitive drum 6, there is a charging device 7 that uniformly charges the surface of the drum 6, an inter-image eraser 57 that removes charges before and after the electrostatic latent image formed by projection imaging by the imaging optical system (2).
a developing device 8 that attaches toner to the electrostatic latent image and visualizes it;
A transfer device 9 that transfers the toner image onto the recording paper P, a separation device 10 that separates the recording paper P from the photoreceptor drum 6, and a blade-like device that removes excess toner adhering to the surface of the photoreceptor drum 6 after transfer. A cleaning device 11, an eraser lamp 12 for erasing charges on the surface of the photosensitive drum 6 after transfer, and the like are provided.

On the other hand, the recording paper P is stored in paper feed trays 13a and 13b installed in the copying apparatus main body
3b, one sheet at a time is taken out by a pickup roller 14a or 14b, passed through a pair of separating rollers 15a or 15b, fed into a sheet feeding path 17 with three pairs of transport rollers 16a to 16c interposed therebetween, and exposed to light by a pair of timing rollers 18. It is sent to the transfer device 9 in synchronization with the formation of an electrostatic latent image on the body drum 6.

Further, a paper feed stacker 19 is attached to the side of the main body X of the copying apparatus. Three types of recording paper P are accommodated in the three stages of paper feed trays 2'Oa to 2Oc of this paper feed stacker 19, and the sizes of the recording paper P accommodated in these paper feed trays 20a to 20c are is specified, the recording paper P of that size is delivered to the paper feed tray 20a, 20b or 20c by the pickup roller pair 21a, 21b or 21c.
The sheets are taken out one by one from the separating roller pair 22a, 22b.
Or after passing through 22c, three conveyor roller pairs 23a to 2
3c is fed into the auxiliary paper feed path 25 in the main body X of the copying apparatus through the paper feed path 24 interposed therein, and after being conveyed to the timing roller pair 18 by the conveyance roller pair 26,
The image is sent to the transfer device 9 in the same manner as above.

The paper feed trays 13a, 13b, and 20a to 20c are equipped with a photo sensor that detects a slint light-shielding portion formed on a paper guide plate and a recording paper in order to detect the size of the recording paper P stored therein and the paper empty state. P
Detection means 55a, 55b, and 56a to 56c are provided, each of which includes a reflective photosensor or the like that detects reflected light from the sensor.

After the toner image has been transferred, the recording paper P is separated from the photosensitive drum 6 and is sent to the fixing device 28 by the conveyance heald 27. The fixing device 28 heats and melts the toner of the toner image transferred to the recording paper P.
Fix it on top.

The recording paper P that has passed through the fixing device 28 is transferred to a pair of transport rollers 29
is guided by a first conveyance switching lever 30 configured to switch the conveyance direction according to the copying mode, and a bypass path 32 leading to a paper ejection path 31 to the outside of the copying apparatus main body χ and an entrance of the transfer device 9. sent to either side.

That is, when copying one original M onto one side of recording paper P (
(Hereinafter, this copying will be referred to as one-sided copying).Regardless of the copying magnification or the number of copies, the recording paper P after passing through the fixing device 2B is sent to the paper ejection path 31, and is transferred to the copying machine main body X by the paper ejection roller pair 33. It is discharged outside.

On the other hand, when copying one or two originals M onto both sides of recording paper P (hereinafter, this copying is referred to as double-sided copying), and when copying a combination of them onto one side of recording paper P (hereinafter, this copying (referred to as composite copying), a fixing device 2B is used.
After passing through, the recording paper P is fed into the bypass path 32.

An intermediate tray 34 for temporarily docking the fed recording paper P is interposed in the bypass path 32. In the case of composite copying, two conveyor roller pairs 35a, 3
5b to the intermediate tray 34. On the other hand, in the case of double-sided copying, two pairs of transport rollers 31a and 37 are guided by the second switching lever 36 before the intermediate tray 34.
The paper is fed into the reversing path 38 with a tray interposed therebetween, and after being turned over, it is fed into the intermediate tray 34.

The recording paper P in the intermediate tray 34 is taken out by the pick-up roller pair 39 when each copying operation is started, for the second side in the case of double-sided copying or the second copying operation in the case of composite copying, and is taken out by the pick-up roller pair 39. After passing through 40, the transfer device 9
The paper is fed into the paper feed path 17 leading to the paper. In the case of double-sided copying and composite copying, the toner image is transferred to the recording paper P in the same manner as in the case of single-sided copying by synchronizing with the timing roller pair 18 and sending it to the transfer device 9, and the toner image is transferred to the recording paper P by the fixing device 28. After being fixed by the image forming apparatus, the image is ejected to the outside of the main body of the copying apparatus χ through a ejecting path 31 provided with a pair of ejecting rollers 33.

A sorter 42 having 20 bins 41 for storing a plurality of discharged recording sheets P in groups is attached to the side of the main body X of the copying apparatus on the paper discharge path 31 side. This sorter 42 includes a pair of paper ejection rollers 3 of the main body X of the copying apparatus.
A receiving roller pair 43 is provided opposite to the receiving roller 3 . and,
The recording paper P discharged from the copying apparatus main body X passes through the pair of receiving rollers 43 and then is sent out onto the bin 41 via a conveyance path 44 in the sorter 42 .

On the other hand, above the document table 1, an automatic document feeder 46 equipped with an automatic reversing device 45 is provided. This automatic document feeder 46 takes out a plurality of documents M placed on the document tray 47 one by one using a pickup roller 48 , separates the documents M and passes them through a pair of rollers 49 , and then transfers them to a transport heald 50 . After the original M is conveyed to a fixed position on the glass plate 1a and the prescribed copying operation is completed,
The document output tray 5 is moved by the conveyance rollers 51a and 51b.
2. Discharge onto the top. Further, when performing double-sided copying etc. from a double-sided document M, the automatic reversing device 45 works with the conveyor belt 50 to reverse the front and back of the document M after copying of one side is completed. Feed it to the fixed position of the glass plate 1a of the table 1.

FIG. 3 is a block diagram of the control device of this copying machine.

A CPU 70 consisting of a microcomputer, which is the main part of this control device, is connected to various keys on an operation panel 60 whose detailed arrangement is shown in FIG. The copy conditions are set and displayed based on the input. Note that after the special copy conditions are set, the CPU 70
Or after the copying operation according to the copying conditions is performed once,
It has a built-in auto-reset function that automatically returns the copying conditions to standard copying conditions if no copying operation is performed before a predetermined period of time (for example, 3 minutes) has elapsed.

Then, the CPU 70 controls the regulator 71 for the exposure lamp 2 and the DC drive for the scanning device S according to the above-mentioned copying conditions.
A controller 73 for the motor DM, a driving stepping motor SM for changing the conjugate length of the imaging optical system I
controller 74 for charging device 7, transfer device 9, and separation device 1°, controllers 75 to 77 for each of charging device 7, transfer device 9, and separation device 1°;
The controller controls the fixing temperature for the fixing device 28, the regulator 79 for the eraser lamp 12, and the regulator 72 for the inter-image eraser 57, and also, although not shown, intermittently drives various rollers for conveying the recording paper P. Controls the operation of clutches, etc.

A controller 73 for the control DC motor DM of the scanning device S receives drive control signals from the CPU 70 in forward and reverse directions to control operations such as movement, reversal, and stopping of the scanning device S. Also, from this controller 73, a driving DC
A signal obtained by shaping the pulse signal from the optical encoder attached to the motor DM is output to the CPU 70, and the C
The PU 70 uses this signal to detect the position of the scanning bag MS.

The controller 74 for the driving stepping motor SM of the imaging optical system I receives a driving control signal from the CPU 70 in the forward and reverse directions, and moves the imaging lens 4 and the fourth mirror 5d to a position where the conjugate length provides a set magnification. move it to.

In the map, the same reference numbers as in FIG. 1 indicate keys and LEDs on the operation panel 60, respectively.

FIG. 1 shows a part of the operation panel 60. As shown in FIG. 61
is a print switch for starting the copying operation, and when this print switch 61 is pressed, copying is performed in the normal mode when arbitrary copying conditions are set as described later, and copying is performed in the normal mode under the standard copying conditions (usually A4 size). When it is set to make a single-sided copy of the same size on the recording paper P (with automatic density setting), copying is performed in the standard mode.

A display device 62 digitally displays various information such as the number of copies and copy magnification. Reference numeral 63 denotes a copy density setting section in which copy density can be set by pressing two keys 63a and 63b. 63c is an automatic density setting key, 63d is an automatic density setting display LED that indicates that the automatic density setting key has been operated, and 63e is a density display LED group that displays the set copy density in steps. 64 is a numeric keypad, and by pressing an arbitrary key, the number of copies and the copy magnification can be set.

Reference numeral 65 represents an interrupt key, and reference numeral 66 represents a clear stop key for canceling settings such as the number of copies inputted using the numeric keypad 64 and interrupting the copying operation. 67 is a paper selection operation section;
a is a selection key, and 67b is a group of LEDs that display the type of recording paper P selected. 68 is a standard magnification setting operation section;
A state in which the copy of the original M is enlarged or reduced equally both vertically and horizontally at one of three preset magnifications by pressing any one of the four keys 68A to 68D, and the same size as the original M. It can be switched to the state where it is performed. 68
A to 68d are LEDs that display the respective standard magnifications.

Although not shown in the figure, the operation panel 60 has a function that divides the document M into separate recording sheets P when copying double-page spreads of the correspondence document.
A book mode key for specifying the book mode to be copied, double-sided copying, composite copying, binding margin shift, partial erasing, partial trimming, and sorting mode, grouping mode, stack mode, and non-sort mode using the sorter 42. Various keys are provided for setting various copying conditions, such as switching the recording paper P corresponding to the size of the document M, and an LED is provided to display each copying condition.

Next, the operation will be explained using specific numerical examples.

When the copying operation is activated by the print key 61, the recording paper P is sent out from the paper feed tray 13a or 13b by the pickup roller 14a or 14b. Assuming that the system speed is 350 mm/sec, the distance from the leading edge of the recording paper P stored in the paper feed tray 13a to the timing roller pair 18 is 360 mm. It takes ゜03 seconds.

When the recording paper P is sent to the timing roller pair 18, it is detected by a microswitch and the optical scanning device S starts. The distance between the standby position of the scanning device S and the document M is 40
mm, a latent image at the leading edge of the document begins to be formed on the photosensitive drum 6 after 0.11 seconds. The distance from the projection section on the photosensitive drum 6 to the transfer device 9 is 100 mm. The distance from the timing roller pair 18 to the transfer device 9 is 75
mm, so in order to align the leading edge of the recording paper P in the transfer device 9 with the leading edge of the document on the photosensitive drum 6, the scanning bag MS starts scanning the leading edge of the document by 25/350=O.
The recording paper P waits on the timing roller pair 18 for 107 seconds. The length from the timing roller pair 18 to the paper ejection roller pair 33 is 550 mm, for example, A4 size horizontal feed (length 21 mm).
In order to completely send out 0 mm), it is necessary to feed 760 mm from the timing roller pair 18, so it takes 2.17 seconds. In total, the minimum time required is 3.38 seconds.

By the way, when the copying operation is started by the print switch 61, the recording paper P is fed out and
After 1=1.14 seconds, a latent image begins to be formed on the photosensitive drum 6. However, if the copying apparatus is left stationary for more than 5 minutes, the photosensitive drum 6 must be charged and erased at least twice until its charging characteristics become stable.

Otherwise, after a dark copy image is obtained on the first copy, the image density decreases on the second copy and thereafter becomes stable. In order to prevent this initial change, a diameter of 100+nm
A processing time of 1.91 seconds or more is required to rotate the photoreceptor drum 5 6 twice and further to send it 40 mm from the charging section to the projection section.

When copying in normal mode with arbitrarily set copy conditions, the time it takes for the recording paper P to reach the timing roller pair 18 after being fed out is 1.03 seconds, the time for the optical scanning device S to reach the leading edge of the document is 0.11 seconds, and the timing The total time of the waiting time of 0.07 seconds at the roller pair 18 is 1.21 seconds, which is shorter than the charging characteristic stabilization time of 1.91 seconds. The copying operation is started after delaying the start time and ensuring charging characteristic stabilization time. As a result, when copying in normal mode, the stabilization processing time after pressing the switch is 1.91 seconds, the waiting time for the edge alignment with the paper is 0°07 seconds, and the recording paper P is ejected from the position of the timing roller on the 1st. It takes more than 4.15 seconds in total, including 2.17 seconds to put it away, to obtain the first copy. Therefore, even if continuous copying is performed, there is no change in copy density.

On the other hand, when copying in the standard mode set to the standard copying conditions, the copying operation starts regardless of the charging characteristic stabilization time of the photoreceptor drum 6, so one sheet is printed in the minimum image forming time of 3.38 seconds. Obtains a copy of the eye. Note that the longer the distance between the paper feed tray and the pair of timing rollers, the longer it will take, so in the case of copying in the standard mode, it is preferable to feed paper from the paper feed tray with the shortest distance.

A timing chart of the above copying operation is shown in FIG.

In FIG. 4, in the standard mode, scanning and copying are started immediately after the exposure lamp is turned on, without waiting until the end of the idle rotation time as in the normal mode. .

Next, the control operation will be explained based on a flowchart.

FIG. 5 shows the main routine that controls the overall copying operation. When this main routine is started by turning on the power, first, all internal registers, flags, RAM, etc. of the CPU 70 are cleared, and initial settings are performed to set the copying conditions to standard conditions (step #1). Next, an internal timer is set to set the length of one routine (step #2). Next, input processing is performed from switches, sensors, etc. provided on each key and other parts of the operation panel 60 (step #3). After that, a "key processing" subroutine is called to perform copying condition change setting processing based on the input from each key of the operation panel 60, which is the copying condition setting means of the input information. Step #4
), then calls a subroutine for data set j that sets display data on the display device 62 (step #5). After that, it is determined whether the copy operation can be started, that is, whether any abnormality has occurred. If it is determined that there is no abnormality (step #6), a control signal and a display signal are output (step #7), and then the "copying process" subroutine is called to perform copying operations under various copying conditions (
Step #9).

On the other hand, if there is any abnormality in the judgment in step #6, the system calls the "abnormality processing" subroutine that stops the operation of each device involved in the copying operation and displays the occurrence of an abnormality (step #8). It will be in a state waiting for the reset button to be operated after being removed. After returning from the "copy processing" subroutine, the state of the copying device, that is, the developing device 8
The presence or absence of developing toner in the paper feed trays 13a, 13
In step #b, the presence or absence of the recording paper P or the presence or absence of temperature abnormality of the fixing roller in the fixing device 28 is detected.
10), after counting up the internal timer (step 41)
1L Wait until this internal timer times up (step #12).

If the internal timer times up, the process returns to step #2 and the above-described operations are repeated thereafter.

In the key processing subroutine, as shown in FIG. 6, it is first determined whether a non-copying operation is in progress (step #2).
1) If a non-copying operation such as a copying operation is not in progress, return as is. If the non-copying operation is in progress, then it is determined whether the print switch 61 is on-edge (step #22).

If it is not on-edge, the process returns as is; if it is on-edge, it is then determined whether the mode is standard mode or not (step #23). If the mode is standard mode, set the standard flag to 1 (step #24), then call the subroutine for other key processing (step #25L, return.On the other hand, if it is determined in step #23 that it is not the standard mode, the standard flag is set to 1). The mode flag is set to 1 (step #26), and the process proceeds to step #25 and returns.

In the copy processing subroutine, as shown in FIG. 7, it is determined whether the standard mode flag is 1 (step #31), and if the standard mode flag is 1, a standard mode copying operation is performed (step #31). #32) Return, and if the standard mode flag is not 1, then determine whether the normal mode flag is 1 (step #33), and if it is not 1, return as is, and if it is 1, copy the normal mode. After performing the operation (step #34), return.

In addition, in the above embodiment, in the case of the standard copying conditions of a specific recording paper size, same size, single-sided, single-sheet copying, and automatic density setting, the copying operation is started immediately without idle rotation as the standard mode. However, the conditions for performing the copying operation in the standard mode may be only one copy and automatic density setting. On the other hand, even in the case of single-sheet copying, the shading of the image quality may be a problem, so it may be configured to be switchable so that a normal mode copying operation can be performed even under standard copying conditions.

(Effects of the Invention) According to the copying apparatus of the present invention, as is clear from the above description, under arbitrarily set copying conditions such as when continuously copying multiple sheets, the photosensitive drum is The machine rotates idly and repeats charging and erasing, and after stabilizing the charging state, the copying operation starts, and copies with uniform image quality can be obtained.On the other hand, when copying only one sheet, copy in standard mode. As a result, the copying operation can be started without idle rotation of the photoreceptor drum, and copies can be obtained quickly.Moreover, since only one copy is being made, there is no need to worry about differences in image quality. do.

[Brief explanation of the drawing]

1 to 7 show an embodiment of the copying apparatus of the present invention,
Figure 1 is a plan view of the operation panel, Figure 2 is a general schematic diagram, Figure 3 is a schematic diagram of the control device, Figure 4 is an operation timing chart, and Figure 5 is the main control flowchart 1.
・The sixth part is a flowchart of key processing, and FIG. 7 is a flowchart of copying processing. 6----,----one photosensitive drum

Claims (1)

[Claims] (1) Under arbitrarily set copying conditions, there is a normal mode in which the photoreceptor drum is rotated idly, charging and erasing are repeated, and the copying operation is started after the photoreceptor drum's charging state is stabilized, and the number of copies is 1. 1. A copying apparatus comprising: a standard mode in which a copying operation is immediately started without idle rotation under standard copying conditions including at least a condition that the number of copies is 1.