JPH01144067A - Automatic double-sided image forming device - Google Patents

Abstract

PURPOSE:To improve the processing efficiency of a double-sided copy by switching a switching means to one-sided operation when the size of a fed sheet of any size except a prescribed double-sided size is detected. CONSTITUTION:When such judgement is conducted that a cassette equipped with copying sheets apart from ones of prescribed size is specified, a switchback solenoid is maintained in off state, and switching guides 23a and 23b are held as solid lines show. Afterwards, the display that single-sided copying is performed is output to a display part to draw operator's attention. Therefore, when a print button is pressed, a copying sheet whose one side is copied passes by the switching guides 23a and 23b from a feed roller 24 and is discharged to a paper discharge tray 4 through a paper discharge roller 25 without entering an inversion route composed of a bypass part 6, an intermediate tray 7 and a U-turn part 8. Thus, even if copying sheets except prescribed ones are supplied, single-sided copying is automatically performed; therefore a machine is not stopped, which contributes to the improvement of the processing efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a copying machine having an automatic duplex function, a laser beam printer, and an improvement in image formation thereon.

[Prior art]

FIG. 2 shows the outline of a conventional copying machine as an example of the automatic double-sided image forming apparatus as described above.

This copying machine 1 has a manual feed tray 2 and three paper feed cassettes 31, 31. ．． 3c is attached, and the copy paper on which the copying process has been completed is discharged to the paper discharge tray 4.

This copying machine 1 has an automatic duplex function that can perform copy processing on both sides of copy paper, and has a switchback section 5 that is different from a copying machine that has only a normal one-sided copying function.
9 Branches 6. It is specially equipped with an intermediate tray 7, a U-turn section 8, etc.

That is, for example, copy paper fed from the manual feed tray 2 to the paper feed roller 9 is detected by a rimming switch 10 that detects the length of the copy paper in the conveyance direction and a length in a direction (width direction) perpendicular to the conveyance direction. After passing through an unillustrated LED (size detection means) provided on the manual feed tray 2, the feed rollers 11m and 11s pass through to the registration rollers 12.

On the other hand, the original placed on the original glass 13 is
Exposure scanned by the light source 14 moving to the right in the figure,
The light reflected from the original surface is reflected by mirrors 151.15b and 15c.
After passing through the lens 16 and being reflected by the mirror 15J, an image is formed on the surface of the photosensitive drum 17.

At a point somewhat earlier than the start of movement of the light source 14, the photosensitive drum 17 starts rotating in the direction shown by the arrow, and the light reflected from the original image is irradiated onto the charge formed by the main charger 18. An electrostatic latent image corresponding to the original image is formed on the surface of the photosensitive drum 17.

The electrostatic latent image is developed into a toner image while passing through the developing section 19 as the photosensitive drum 17 rotates.

When this toner image passes through the transfer section 20, it is transferred onto the copy paper fed by the registration rollers 12.

The copy paper on which the toner image has been transferred passes through a conveyor belt 21 and reaches a fixing roller 22, where the toner image is thermally fixed.

Here, if the current copy mode is single-sided copying, the switching guides 23m and 23b are positioned by a switch bank solenoid (not shown) in the state shown by solid lines. Therefore, the copy paper after the fixing process leaves the fixing roller 22, passes through the feed roller 24, and then passes through the switching guide 23. ．． 231, and is discharged from the paper discharge roller 25 to the paper discharge tray 4.

Further, when the copy mode is set to double-sided copying and the first side (front side) copying is performed, the switching guides 231 and 23 are switched to the state shown by the broken line by the switch puncture solenoid. There is. Therefore, the copy paper sent out by the feed roller 24 is transferred to the switching guide 23m, which is switched to the position shown by the broken line above.
Guided by 23I, switch bank guide 26
At this time, the driven-only switch bank roller 27 is separated from the upper roller of the paper discharge roller 25 as shown in the figure, so the copy paper is fed by a predetermined amount into the switchback guide 26 by the feed roller 24. It will be done.

After that, the switchback roller 27
By being pressed by the upper roller, the traveling direction of the copy paper is reversed, and the copy paper is sandwiched between the feed roller 24 and the guide wall 2i, and by the rotation of the feed roller 24, the copy paper is transferred to the branch tray 6a of the branch section 6, It is sent in the direction of 6+. These branch trays sa, sh are selectively swung according to the size of the copy paper measured by the above-mentioned rimming switch IO, and accurately send the fed copy paper to the intermediate tray 7. .

The copy paper thus fed into the intermediate tray 7 is further fed into the registration rollers 12 via the U-turn section 8 by the paper refeed roller 30, and thereafter is fed into the registration rollers 12 through the U-turn section 8.
2. Transfer section 20. Conveyor belt 21. It passes through the fixing roller 22 and is sent to the feed roller 24. At this time, the switching guide 23. ．． 23b is switched to the position indicated by the solid line, and the copy paper sent out from the feed roller 24 is ejected to the paper ejection tray 4 via the paper ejection roller 25.

A conventional copying machine 1 having an automatic duplex function is configured as described above, and when performing double-sided copying, the intermediate tray 7 must be loaded once. In order to improve the processing efficiency when copying sheets, it has a function to temporarily stock the multiple sheets of copy paper mentioned above, and also to make the width of the copy paper aligned perpendicular to the transport direction of the delivered copy paper. , the copy image for the second side is copied at a predetermined position on the copy paper.

Therefore, in the intermediate tray 7, the width alignment plate for performing the width alignment as described above is slightly moved in a direction perpendicular to the paper surface of FIG. 2 to perform the width alignment. ,
Although such a width alignment mechanism is generally applicable to copy paper of a predetermined size, it is not possible to properly align the width of copy paper of a special size outside the predetermined size.

For this reason, in conventional automatic double-sided copying machines, for example, B5, which has a relatively high frequency of double-sided copying. A4. When copy paper of a predetermined size such as B4 is supplied, double-sided copy processing is executed, but for example, copy paper of a non-specified standard size such as A3 or A5, or a copy paper of a non-specified size such as A3 or A5 is supplied. The copying operation is not performed when paper feeding from a paper feeding cassette containing copy paper is selected or when copy paper of a size other than the standard size is fed from the manual feed tray 2.

[Problem that the invention seeks to solve]

However, in many cases, operators are unaware of the rule that the copier will not accept double-sided copying if the currently supplied copy paper is of a size other than the specified size. In most cases, the operator wishes to switch the duplex copy mode to the single-sided copy mode and execute the copy process, so if duplex copying is selected for non-specified copy paper as described above, the duplex copy will not be accepted. It would be more in line with the operator's wishes to perform one-sided copying than not to do so, but with conventional copiers, as mentioned above, double-sided copying is not supported, which is not efficient. It wasn't a good thing.

It is also theoretically possible to have a copier that can handle double-sided copying for almost any size of copy paper that can be copied, but in this case a large intermediate tray that accommodates the maximum size would be required. This increases the size of the machine, the number of branch trays 61.6 described above increases, and the control thereof becomes complicated.

Therefore, an object of the present invention is to improve the above-mentioned inefficiency during double-sided two-beam processing.

[Means for solving problems]

In order to achieve the above object, the present invention provides an automatic double-sided image forming apparatus comprising at least a size detecting means for detecting the transfer paper ψ size and a switching means for switching between a single-sided processing path and a double-sided processing path. When the size detection means detects that the paper feed size is other than the predetermined size that can be processed on both sides, the switching means is switched to the single-sided processing side. A forming device is provided.

[Effect]

If the fed copy paper is of a special size that cannot be processed on both sides, the switching means is switched to the single-sided processing side, and the copy paper on which copying processing has been completed on only one side is discharged.

〔Example〕

Next, with reference to the flowchart shown in FIG. 1, an embodiment embodying the present invention will be explained to provide an understanding of the present invention. It should be noted that the following examples are merely examples embodying the present invention, and are not intended to limit the technical scope of the present invention.

In the following examples, 31. B2. ... indicates the number of the processing procedure (step).

The flowchart shown in FIG. 1 is part of a main program controlled by a microcomputer that controls the copying machine, and first, it is determined in Sl whether or not the duplex mode is currently set.

The duplex mode can be set, for example, by checking a duplex mode flag that is turned on or off when a mode switching key provided on the operation panel is pressed.

If it is determined in S1 above that the duplex mode is currently set, in B2, the copy paper that is about to be fed or the copy paper that has been fed has a predetermined size that allows double-sided copying. It is determined whether or not. For example, when paper is fed from a paper feed cassette, such detection of the size of copy paper can be determined based on the size of the copy paper accommodated in a designated paper feed cassette, that is, the type of paper feed cassette. In addition, when paper is fed from the manual feed tray 2, the time from the on signal to the off signal from the limit switch 10 that detects the leading edge and trailing edge of the copy paper sent out by the paper feeding roller 9 is measured,
This is possible by measuring the length in the width direction using an LED (not shown).

These means constitute the size detection means.

However, this embodiment employs means for determining the type of designated paper feed cassette.

In S2, if it is determined that a paper feed cassette loaded with copy paper of a predetermined size capable of double-sided copying is designated, the switching guide 23. For example, a switchback solenoid that swings the switching guides 23. and 23I is turned on, and the switching guides 23. , 23 & second
The switch is made to the position shown by the broken line in the figure (S3).

As a result, when the print button is subsequently pressed in S4, the copy paper on which one side has been copied passes through the switch bank section 5° branch section 68, intermediate tray 7, and U-turn section 8, and is then reversed. Thereafter, a so-called double-sided copying process, in which the other side is subjected to a copying process, is executed (S5).

On the other hand, if it is determined in S2 that a cassette containing copy paper of a size other than the predetermined size is specified, the switch bank solenoid is kept in the OFF state, and the switching guides 23□ and 23b are connected to the solid line. Condition and S
6) After that, a message indicating that one-sided copying will be performed, for example, "Single-sided copying" is output on the display unit to alert the operator (S7).

Therefore, when the print button is subsequently pressed in S4, the copy paper that has undergone copy processing on one side is transferred to the branch 6. Do not enter the reversing path such as the intermediate tray 7 or the U-turn section 8 (from the feed roller 24 to the switching guide 2).
3m and 23I, passes through the paper ejection roller 25, and is ejected to the paper ejection tray 4 (S5).

In process 5 above, the duplex mode setting is maintained and only the switchback solenoid is turned on and off.
The copy paper path is switched, but if, for example, in step S2 it is determined that the copy paper size is other than the predetermined size, the mode is completely switched to single-sided mode (the switchback solenoid is also switched of course). It is also possible to do so.

In the above embodiment, when duplex copying is performed, if the size of the copy paper fed from the manual feed tray is special, the duplex copying is switched from duplex copying to single-sided copying, but in the case of paper feeding from the manual feed tray, Since there are various types (materials) of manually fed transfer paper, even if double-sided copying of a predetermined size of copy paper is specified, it is also possible to switch to single-sided copy processing. Therefore, in this case, double-sided copying is performed only when paper feeding from the paper feeding cassette is selected.

〔Effect of the invention〕

As described above, the present invention provides an automatic double-sided image forming apparatus comprising at least a size detecting means for detecting the size of transfer paper and a switching means for switching between a single-sided processing path and a double-sided processing path. This is an automatic double-sided image forming apparatus characterized in that when the means detects that the paper feed size is a size other than a predetermined double-sided processable size, at least the switching means is switched to the single-sided processing side. , when a copy paper other than the specified copy paper that cannot be processed by the copying machine is supplied,
Since one-sided copy processing is performed automatically and the machine does not have to be stopped, processing efficiency is improved.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the processing procedure of an automatic duplex image forming apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic side sectional view showing the schematic configuration of a conventional automatic duplex copying machine. [Explanation of symbols] 1... Copy machine 2... Manual feed tray 5...
Switchback 6... Branch 7... Intermediate tray 8... U
Turn part 10...Limit switches 23m, 23b...Switching guide.

Claims (1)

[Scope of Claims] An automatic duplex image forming apparatus comprising at least the following: size detection means for detecting the size of transfer paper; and switching means for switching between a single-sided processing path and a duplex processing path; When it is detected that the paper source size is other than the specified size that can be used for duplex processing,
An automatic double-sided image forming apparatus characterized in that at least the switching means is switched to a single-sided processing side.