JPH0452946B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrostatic copying machine, particularly to a transfer type copying machine that performs electrophotographic dry development, and particularly to a double-sided copying machine capable of making single-sided and double-sided copies.

[Prior art]

Copying using copiers has traditionally been done mostly by single-sided copying due to the complexity of operation, maintaining the order of pages, and the complexity and bulk of the equipment. Double-sided copying is desired due to the appearance and weight of the copy booklet, and many copying machines for double-sided copying have already been proposed. For example, JP-A-52-137341, JP-A-Sho
No. 54-43742, etc., and proposals such as Japanese Patent Application No. 58-85103 are referred to regarding double-sided copying.

Each of the above-mentioned proposals relates to the function of double-sided copying, and does not give consideration to the suitability of using the stored image as a recording medium.

That is, in single-sided copying, transfer paper that is as thin as possible is preferred in view of resource saving, storage space, weight, etc., and for example, paper with a basis weight of about 65 g/m ² is used as a standard. However, in the case of double-sided copying, if the paper is thin, it is very difficult to see the image on the front side through which the image on the back side is reflected, and it also looks bad as a booklet. Furthermore, double-sided copying inevitably requires passing the paper twice, and stiff, thin paper tends to wrinkle, and if jamming occurs, it is necessary to redo the copying operation twice for the front and back sides, and the document must be taken out again. etc., the post-processing of copy failures is surprisingly complicated.

[Purpose of the invention]

The present invention provides a copying machine capable of both single-sided and double-sided copying, which allows double-sided copying to be performed without difficulty in identifying the back side image by transparency and without causing accidents such as jamming when performing double-sided copying. The purpose is to provide a double-sided copying machine.

[Structure of the invention]

The present invention provides a detection means for detecting paper thickness,
When only thin recording paper is being fed by the output from the control section controlled based on the information from the paper thickness detection means and the signal from the copy designation section in the single-sided/double-sided copying machine. The apparatus is configured such that double-sided copying is stopped, and includes a plurality of paper storage sections and paper feeding means, a paper thickness detection means for detecting whether the paper fed from each paper feeding means is thick paper or thin paper; The paper thickness detecting means includes a one-sided copy designation section and a two-sided copy designation section, and the paper thickness detection means detects that all of the paper in one or more paper feeding sections that can be fed when starting double-sided copying by the two-sided copy designation section are thin paper. This can be achieved by a single-sided/double-sided copying machine characterized by having a control means for prohibiting double-sided copying.

〔Example〕

An embodiment of a single-sided/double-sided copying machine according to the present invention is shown in FIGS. 1 to 4.

The mechanism and operation will be explained below based on the drawings.

FIG. 1 shows a schematic configuration of an embodiment of a single-sided/double-sided copying machine according to the present invention, in which a platen glass P on which a document M is placed is provided on the upper surface of a main body 1, and this platen glass P inside the main body 1 is provided. A scanning optical system 2 is provided below. The scanning optical system 2 includes a reciprocating document illumination lamp 2a, mirrors 2b and 2c, and a fixed lens 2d and mirror 2e. A photoreceptor drum 3 is provided in the center of the main body 1 so as to be rotatable in the direction of the arrow, and a charging electrode 4 for uniformly charging the photoreceptor 3a along the rotational direction and a developing sleeve 5a are built in around the drum. developing device 5
, a transfer electrode 6 , a separation electrode 7 , and a static elimination electrode 8
and a cleaning device 9 are arranged in this order. Paper feed cassettes 10, 10' which are paper storage units
Two types of recording paper having different thicknesses are stored in the main body 1, that is, thick paper is stored in the paper feed cassette 10, and thin paper is stored in the paper feed cassette 10'. Inside the paper feed cassettes 10 and 10', there is a bottom plate 1 that lifts the recording paper upward by a pressure roller 11.
2, 12' are provided. Reference numerals 13 and 13' are paper feed rollers that feed the recording paper stored in the paper feed cassettes 10 and 10' to the position of registration rollers 14, which will be described later, to prevent the recording paper from being fed in an overlapping manner. For this purpose, the rollers 13a and 13a are rotated via belts, and a stop roller 13b is provided. Reference numeral 14 denotes a registration roller that temporarily stops the recording paper fed by the paper feed roller 13 or 13', and then feeds the paper again toward the transfer position in synchronization with the leading edge of the image on the photoreceptor 3a. As shown in FIG. 2, photocoupler units P and P' connected to paper thickness signal generating means are provided between the registration roller 14 and the paper feed rollers 13 and 13', respectively. The amount of light transmitted through the recording sheets 110 and 110', which have been slightly unloaded from the recording paper 10' and stopped, is in a state of being detected. Reference numeral 15 denotes a conveying device that conveys the recording paper after transfer to a fixing position, and the fixing device 16 includes a heating roller 16a and a pressure roller 16b. 17 is a recording paper reverse feeding device 18 for transporting the recording paper after fixing.
This recording paper reverse feed device 18 is a paper ejection roller that ejects paper to the paper ejection roller 17, which is separate from the main body 1.
It is provided on the paper ejection side of the printer, and consists of a forward rotation roller 18a and a forward and reverse rotation roller 18b. Reference numeral 19 denotes a sorter provided on the discharge side of the recording paper reverse feeding device 18 to align the pages of the recorded material, and 20 indicates a single-sided recorded record fed from the recording paper reverse feeding device 18 provided in the mount 21. This double-sided tray 20 is a double-sided tray that temporarily stores paper.The front of the feeding direction (right side in the figure) of this double-sided tray 20 is oriented slightly downward in order to make it easier to store recording paper, and the recording paper is placed against the front side of the device. To align them, the front side of the device is tilted downward. Further, the double-sided tray 20 is provided with a side regulating plate (not shown) that is movable according to the width size of the recording paper, and a double-sided tray auxiliary guide plate 231, which will be described later. 22 is a duplex tray 20 for transferring the recording paper from the recording paper reverse feeding device 18 during double-sided copying.
Auxiliary conveyor belts, 23, 23', 2
3'' is a pressure roller that can swing freely in the direction of the arrow by a parallel four-bar link 24, and these pressure rollers 2
3, 23', and 23'', double-sided tray auxiliary guide plates 231 for holding the recording paper on the side of the auxiliary conveyance belt 22 are loosely attached to form a parallel four-bar link structure. pressure roller,
23, 23', 23'' are double-sided tray auxiliary guide plates 2
31, and is pressed against the auxiliary conveyance belt 22 according to the size of the recording paper during double-sided copying. When the size of the recording paper is large (for example, A3 size), only the left roller 23 moves to the position shown by the chain line, and when the size of the recording paper is medium (for example, B4 size), the left and center rollers 23 and 23 move. ' moves to the position shown by the chain line, and when the recording paper size is small (for example, A4, B5 size), the three rollers 2
3, 23', and 23'' are all moved to the position indicated by the chain line. 25 is a paper refeed roller for feeding again the recording paper on which one-sided copying has been completed in the duplex tray 20; The paper feed roller 25 is also designed to prevent double feeding in the same manner as the paper feed rollers 13 and 13'.As can be seen from the figure, the double-sided tray 2
0, the auxiliary conveyance belt 22, the pressure roller 23,
23', 23'', link 24, and paper refeed roller 2
5 is provided in a record holding section 26 that can be moved up and down within the pedestal 21. Reference numeral 27 denotes an intermediate roller provided between the rollers 14 and 25 for conveying the recording paper fed by the paper refeed roller 25 to the position of the registration roller 14.

Next, the operation of the single-sided/double-sided copying machine will be explained.

First, when copying is to be performed on only one side of the recording paper, set the copy designation section to one-sided copy mode and operate the copy button.The original M on the platen glass P is exposed and scanned by the scanning optical system 2, and the photoreceptor of the photoreceptor drum 3 is An electrostatic latent image of the document M is formed on 3a. The electrostatic latent image is made into a visible image by the developing device 5, and the visible image is transferred by the transfer electrode 6 onto a thin recording paper from the paper feed cassette 10' of the main body 1. After the transfer, the recording paper is separated from the photoreceptor 3a by the separation electrode 7, conveyed to the fixing device 16 by the conveyance device 15, fixed there, and sent to the recording paper reverse feed device 18 by the paper discharge roller 17. At this time, each of the rollers 18a and 18b of the recording paper reverse feed device 18 is rotating forward (rotation direction that guides the recording paper toward the sorter 19 side), so the recording paper is sorted into the sorter 19 with its copy side facing upward. Ru.

On the other hand, when copying on both sides of recording paper, set the copy designation section to double-sided copy mode and turn on the copy button.
0 onto a cardboard recording paper by a transfer electrode 6. After the transfer, the recording paper is separated from the photoconductor 3a by the separation electrode 7, and transported by the transport device 15 to the fixing device 16, where it is fixed and transferred to the paper ejection roller 1.
7, the recording paper is sent to the recording paper reverse feeding device 18. At this time, the roller 18b of the recording paper reverse feed device 18 rotates in the reverse direction (rotation in the opposite direction to the forward rotation), and the auxiliary conveyance belt 22 starts to drive, and the pressure rollers 23, 23', 23'' according to the recording paper size are rotated. When moving to the position indicated by the chain line, the side regulating plate moves, and the recording paper, on which one side has been copied through the series of copying processes described above, is transported toward the roller 18b by the roller 18a of the recording paper reverse feeding device 18. Since the conveyance force of the roller 18a is greater than that of the roller 18b, the recording paper is conveyed with its leading edge sliding on the roller 18b.The roller 18b is not in strong pressure contact with the recording paper, and the conveyance is The force is weak and the roller 18a
No jamming occurs due to the conveying force. After that, when the trailing edge of the recording paper leaves the roller 18a, the conveyance force towards the roller 18b side (paper ejection direction) is lost, and conversely, the conveyance force in the opposite direction by the roller 18b works, albeit weakly, and the recording paper continues until that point. The paper is fed backwards with the rear end leading, and is sandwiched between the auxiliary conveyance belt 22 and pressure rollers 23, 23', 23'' that can be moved up and down according to the size of the recording paper and driven by the auxiliary conveyance belt 22, and the copy surface is The paper sheets are guided to the double-sided tray 20 in an upwardly facing state.A set number of recording sheets are sequentially stacked in the double-sided tray 20 through a similar process.
When a predetermined number of recording sheets are stacked in the double-sided tray 20 (the number of stacked sheets is based on the set number of sheets), the drive of the auxiliary conveyance belt 22 is stopped, and the forward tilting state (not shown) of the double-sided tray 20 is released. and become parallel. At this time, the double-sided copy signal is simultaneously copied and the copying operation for the back side starts. That is, the uppermost recording paper in the duplex tray 20 is lifted upward via the middle plate 102 by the rotation of the bottom plate 101 and is pressed against the paper refeed roller 25 .
Thereafter, the paper refeed roller 25 starts rotating, and the uppermost recording paper in the duplex tray 20 is fed by the paper refeed roller 25 toward the main body 1 side. At this time, since the forward inclination of the double-sided tray 20 is already kept parallel, the paper can be easily fed by the rollers 25. The recording paper fed by the paper refeed roller 25 passes through the intermediate roller 27 and is sent to the position of the registration roller 14, and the subsequent recording paper follows the same path as in the case of previous one-sided copying. undergoes a series of copying processes. The recording paper on which double-sided copying has been completed is discharged by the paper ejection roller 17, the roller 18a of the recording paper reverse feeder 18, and the roller 18b which is already rotating in the forward direction, with the copy side that has been copied later facing upward, and then sent to the sorter. If equipped, it will be sorted into sorter 19.

As described above, in the single-sided/double-sided copying machine of the present invention, regardless of whether the copy designation section is set to one-sided or double-sided copy mode, by operating the copy button, paper selection appropriate for the copy mode, that is, the appropriate thickness is selected. The control and operation of this function is performed as follows.

That is, as shown in FIG. 3, the control unit (CPU) of the copying machine receives a signal from a single-sided or double-sided copy designation unit, the so-called copy mode designation unit, and the photocoupler units P and P' shown in FIG. Information regarding the amount of light transmitted through the recording paper, that is, paper thickness information, is input, and the presence and arrangement of thick or thin recording paper are identified by the memory that stores the specific amount of transmitted light. .

If only the thin recording paper 110' as the paper thickness information in FIG. 3 is input to the control unit (CPU) as a detection result, even if the copy button is operated as shown in FIG. Even though a double-sided copy mode signal is input, double-sided copying is not activated, and by switching to single-sided copying mode, single-sided copying is performed using thin recording paper 110'.

On the other hand, if only the cardboard recording paper 110 is input as the detection result, copying can be performed in either double-sided or single-sided copy mode, as shown in FIG.

Note that instead of detecting the paper thickness of the recording paper using the photocoupler units P and P' in the first half, the recording paper 110 and 1
Paper feed cassettes 10 and 10' each containing a paper feed cassette 10' are provided with their own dedicated detection parts,
It is also possible to indirectly detect the thickness and location of the recording paper using a plurality of microswitches or the like.

〔Effect of the invention〕

The present invention provides a single-sided/double-sided copying machine that can perform only one-sided copying on thin recording paper and either one-sided or both-sided copying on thick recording paper. Now it is possible to obtain two-sided copies that are easily certified and one-sided copies that are economical and require little storage space.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a single-sided/double-sided copying machine according to the present invention.
Figure 2 shows the main parts. FIG. 3 is a control circuit diagram of the copying machine. Figure 4 is the flowchart. 10, 10'...paper feed cassette, 110...
(Thick paper) Recording paper, 110'... (Thin paper) Recording paper, 1
3, 13'... Paper feed roller, P, P'... Photo coupler unit, 14... Registration roller, 18
... Recording paper reverse feeding device, 19 ... Sorter, 20 ...
...Double-sided tray, 25... Re-feed roller, 27...
intermediate roller.

Claims (1)

[Claims] 1. A plurality of paper storage sections and paper feeding means, a paper thickness detection means for detecting whether the paper fed from each paper feeding means is thick paper or thin paper, a single-sided copy specification section, and a double-sided copy specification section. and when the paper thickness detecting means detects that all of the sheets in one or more paper feeding units that can be fed when starting double-sided copying by the double-sided copy designation unit are thin paper, a copying operation of double-sided copying is performed. A single-sided/double-sided copying machine characterized by having a control means for prohibiting.