JPS5840562A - Both side image recording apparatus - Google Patents

Abstract

PURPOSE:To enable duplicate paper feeding to be recognized in a both side copy mode, by detecting density of the front side of a copy. CONSTITUTION:A toner image formed on a drum 1 is transferred on the front side of a transer paper P, passed through a fixing device 7, and discharged to an intermediate tray 9 with the front side up. The paper P is again introduced, a toner image is transferred on the reverse side of the paper P, and discharged to a discharge tray 12 or a sorter 17. The light reflected from the front side of the paper P is measured with a photoelectric detector 15 on the intermediate tray 9, and when the density of the toner image is low, it is judged that the paper P is doubly fed from a cassette 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the detection of image defective sheets in a double-sided image recording apparatus, and in particular, when double feeding occurs when the first side has already been recorded during a double-sided recording operation, the second side When a sheet is fed during recording, a blank state on the first side is detected, the apparatus is stopped, and the sheet can be removed.

In general, in image recording devices such as copying machines, it is considered difficult to store multiple recording sheets, but for example, storing one copy of the first side of copy paper, which is a recording sheet, in one place. In a copying machine that refeeds paper from a storage section and copies the second side, paper alignment is performed in the storage section. Therefore, in the process of copying the first side, copy sheets that are difficult to separate are often avoided and are fed separately when copying the second side, and in this case, the storage section (hereinafter referred to as relay tray) is This results in a surplus of copy paper that exceeds the number of copies. Of course, a solution would be to copy all the copies on the second side of the paper in the relay tray, but if a collating machine is used, there will be inconveniences, and furthermore, only the second side will be copied on some parts. However, when it comes to obtaining copy paper, it is inevitable that a large amount of paper, toner, and electricity will be wasted.

Therefore, in the present invention, recording sheets that are fed multiple times during the recording operation of the first side are usually separated and fed when recording the second side, and also when copying the first side. In consideration of the sentiment that if the double-feed paper is double-feeded again, the records on the first and second paper pages will not be deleted, but the paper on the first page and the second paper are simply different. The density detection means (i.e., the image presence/absence detection means) detects that there is no recorded image on the first side of the sheet that was double fed during the recording operation.
This paper is designed to detect the first side of the sheet and stop unnecessary recording of the first side of the sheet. In a double-sided image recording apparatus, a recording sheet on which the first side has been recorded stored in a storage section is conveyed to the image recording section by a second sheet feeding means to perform image recording on the second side. There is provided a double-sided image recording apparatus characterized in that at least one first side recording degree detecting means is disposed in a recording sheet conveyance path leading to a recording sheet.

Hereinafter, an embodiment in which the present invention is applied to a copying machine having a double-sided copying device will be described based on the drawings.

Figures 1 to 4 show one embodiment of the present invention.
The figure is a longitudinal sectional view of a double-sided copying apparatus using the present invention. Since image formation, development, transfer, and fixing S use already known techniques, their explanation will be omitted.

Next, the configuration and operation of the copying machine will be explained in the order in which the recording sheets C) are conveyed. Figure 2 shows the operation section for this copying machine. Menu 201 is used to select the same size to obtain double the number of copies, menu 202 is used to select normal copy density, and menu 202 is used to select transfer paper. The tray has a tongue 203 at the ninth position when it is placed on the tray, the lower tongue 204 is for transfer paper to be fed from the lower side 1 of the two-tiered paper feed table, and the 1st double-sided tongue 204 is for double-sided copying. presses the button 205 and sets the number of copies to 20.

Such copy magnification and other operation settings are performed via a required control circuit (by pressing down each group of keys shown on the operation section in FIG. 2(b)), and as a result, the copying machine shown in FIG. , corresponding to the operation set state, is set to six copy preparation states, but the different configurations for this are not directly related to the present invention and will therefore be omitted.

Then, by inputting the double-sided methane 2050, the paper ejection guide 8 shown in Fig. 1 is switched to the position a, and the display section shown in Fig. 2 (a) displays the message "Please place the original on the first side." , when the original on the first side is placed and the cohesive methane 206 is pressed, a double-action operation is started.The copy paper P on the sketch paper tray 1 is fed by the lower paper feed row 22 and synchronized with the image on the photosensitive drum 4. The copy paper is taken by the register roller 3, passes through the transfer section 5, the conveyance section 6, the fixing device 7, the switching guide 8, and is stored in the relay tray 9 with the image side facing up.The relay tray 9 stores the copy paper in preparation for the next feeding. Width alignment and leading edge alignment are performed (in this case, the rear edge before entering the relay tray is the leading edge).In this example, when the first side of 20 copies is stored, copying is interrupted. "Please place the original on the second side" is displayed on the display and the switching guide 8 moves to position C.

Next, when the second side original is placed and the copy button 206 is pressed again, the copying operation for the second side is started.

The copy paper on the relay tray 9 passes through the relay conveyance path 11 and is again synchronized with the image on the drum 4 by the register roller 3, the second side is transferred, conveyed, fixed, and discharged onto the tray 12 via the switching guide 8. Ru.

In the above copying operation of the first WJ and the second side, the first
If double feeding of copy sheets occurs during the copying operation of the first side, the double fed copy sheets are often transported in the relay tray 9t in the overlapped state. In this case, if double-feeding sheets are separated, in this example, the sensors 131 to 131 arranged along the copy paper conveyance path detect this as a conveyance abnormality and treat it as a jam. It is configured. This point will be discussed further later.

The feature of this example is that the above-mentioned copy paper of the first page is transferred to the second page.
The feature is that it detects that an image has been recorded on the first side when feeding and conveying from the relay tray 9 for side copying, and the density detection sensor for this purpose in this example 1s is arranged above the relay tray 9.

In this example, the density detection sensor 15 is provided so as to be able to scan a predetermined range (length) of the copy paper in order to detect the presence or absence of an image on the first side of the copy paper with sufficient reliability. The specific configuration for this will be described below.

In addition, in view of the fact that the reference level used by the sharpness detection sensor 15 to detect the presence or absence of an image changes depending on the background color of the copy paper, in this example, the white to
For example, when the copy paper is white, the button 207 is pressed, and when the background color such as blue cannot be specified, the level can be selected by selecting the button. This function can be canceled using the OFF & button 208.

In the above configuration, the copy sheets that are double-fed and stored in the relay tray 9 when the first side is not copied are subjected to width adjustment and edge alignment in the relay tray 9, so that so-called "one-sheet handling" is performed. Therefore, when the sheets are fed by the paper feed row 210 for copying #lK and 2!lJ, even the sheets that are multi-fed will be separated and fed one by one. The uncopied paper is detected by the density detection sensor 15.
This means that it is detected that the page is blank. In such a case, it would be useless to copy the second side of the copy paper on which the first side has not been copied, so it is best to remove it from the specified conveyance process. For example, the copy paper that is in the process of copying the second side before the detected blank paper is conveyed continuously and placed in the output tray 12, and after all of the paper has entered the tray 12, the jam display 231 is performed and the copy paper is transferred to one relay tray. After removing the blank paper in the relay tray 9, press the copy button 206 again to start copying the second side.

The density detection sensor 15 is used as a detection unit, and a necessary control circuit is used to stop the operation of the copying machine due to abnormality detection and to display the jam display status. When the side image is not detected, the paper feeder 210 at the upper end of the relay tray 9 is stopped, and furthermore, the copy paper that has been conveyed before the first side is ejected from the copying machine onto the output tray 12. When sensor 13
When the copy paper being conveyed is no longer detected at a113b, 18e, 13d, and ish, the operation of the copying machine may be stopped, a jam display, etc. may be performed.

An example of such a series of operational relationships is shown in FIG. In addition, in FIG. 1, the sensors 14a114b and 16
m, 16ba shows an element for detecting the presence or absence of copy paper. In addition, when using the collating machine 17, the switching guide 8 is switched to position b and the copy paper after copying on the second side is transferred to the collating machine 17.
What is necessary is to have it transported by.

Next, a preferred embodiment for detecting the uncopied state of the first side of the copy sheet by the density detection sensor 15 will be explained with reference to FIG. A sensor base 303 is installed on the guide rods 301 and 302 so as to be slidable in the axial direction.
A rack 304 parallel to the guide rod 301 is fixed to one end side. This rack 304 is connected to a gear 3 attached to a motor 305 fixed to a fixed part of the main body of the copying machine.
07, and this movement is caused by a gear 308 of a potentiometer 306 fixed to the main body of the copying machine.
The device is designed to be moved and stopped within a predetermined range and position upon detection by the user.

Therefore, due to the input of the motor 305) the sensor base 3
03 moves in the direction of the arrow (G), and the potentiometer 306
It detects the position and stops.

A rotatable shaft 309 is attached to the sensor base 303, and an output shaft of a power meter 310 and a potentiometer 311 are fixed to this shaft 309. What is the other end of the chain 312 that engages with the sprocket 310?1. The output shaft of a motor 314 is fixed to the sprocket 313 that engages with the f rocket 313, and the motor 314 is fixed to the sensor base 303.

A part of the chain 312 includes concentration detection +7 servo 1.
5 is attached so that the chain 312 moves along a groove 303a formed in the longitudinal direction of the base 303.

That is, as the motor 314 rotates, the sensor 15 moves in the direction of the arrow in the figure, and its position is detected by the tension meter 311, so that it can be stopped at a predetermined position. The concentration detection sensor 15 is moved by the motors 305 and 314 as indicated by the arrows (4) and (6) in the figure.
) direction.

A movable arm 315 is attached to the concentration detection sensor 15. An arm 316 is movably attached to the arm 315, and a shaft 31 is fixed to the sensor base 303 at the other end of the arm 316.
7 is engaged, and a threaded spring 318 attached to this shaft 317 applies a moment to the arm 316 to rotate it in the direction of arrow C. Concentration detection sensor 15
The wiring cable 321 is held by the arms 315 and 316 using pulleys 319 and 320, and is combined with the cables of the motor 314 and podensimeter 311.
2. The goo attached to the side plate of the fixed part of the copier body! J-323 and is guided to a required control board (not shown).

According to such a configuration, the density detection sensor 15 slides while being guided by the 3 G 3 m of the sensor base 303, so there is little vibration due to movement, and the density detection sensor 15 does not move as if it were a so-called blank sheet due to the reflection density from the light emitting element and the light receiving element. The image area is determined, and in the case of paper with a white background color and paper with a red or blue background color, the reference level is changed to make it easier to distinguish between uncopied paper and copied paper.

FIG. 4 is a plan view showing the relationship between the document placement position and the operation of the celsius detection sensor 15. Figure 4 0) is the placement position of the original,
This indicates the condition, and the lower right corner is the standard. Therefore, the images on the relay tray 9 are aligned so that the upper left serves as a reference as shown in FIG. 4(b). Now, if B4 size copy paper is selected, the density detection sensor 15 moves to the position of the black circle 401 and stops.

When the copy paper for the first side copy method is collected in the relay tray 9, if a signal with an image is received by the density detection sensor 15, the paper maintains its position and synchronizes with the signal from the paper feed row 210 (FIG. 1). The presence or absence of an image on the copy paper to be fed is detected, and if it is an image portion, the paper feed is immediately stopped and processing such as stopping the copying machine described above is performed.

In addition, in the case of this example, since the density detection sensor 15 is provided with mobility in the directions (4) and (6) in FIG. 3, the image is detected only at the point 401 on the copy paper. By detecting the presence or absence of an image over a wide range without spreading it out, better detection ability can be obtained. That is, when positioning the concentration detection sensor 15, the black circle 40
If the sensor 15 is not present at position 1, the sensor 15 is moved from the black circle 401 to the circle 402 as shown in Figure 4C, and stopped at the position where the image is detected, but if it is still absent, Following the arrow, it moves from circle 402 to circle 402a, and then to circle 401&, ending at circle 404. Ten thousand
If the circle 404t is not scanned, the copy paper in the relay tray 9 is judged to be normal and sent out.

If it takes a long time for the sensor 15 to move from position 401 to position 404, the time to start copying the second side will be delayed, but if you want to speed it up, increase the number of sensors by increasing the detection area of the sensor 15 and increasing the number of chains. However, in reality, if you consider the time required to replace the second side document, there is almost no problem with the configuration of this embodiment, and in normal conditions, the first side image is detected during scanning. Therefore, when the copy paper size is small, there is no problem of smearing. In addition,! 4
The black circles shown in Figure (b) indicate the starting points of image detection corresponding to each size of copy paper.

In addition, in the case of a high-speed copying machine, there is a possibility that paper feeding may be delayed, so it is better to operate the density detection sensor 15 in synchronization with the signal from the sensor 13f (Fig. 1) that the previous copy paper has passed. desirable above.

In the above-described embodiment, the density detection sensor was moved in the traveling direction of the copy paper and in a direction perpendicular thereto, but in order to shorten the amount of movement and shorten the travel time, it was moved in the diagonal direction of the copy paper. According to experiments, the width is 30-
Good results were obtained even when scanning diagonally. In such cases, it has been found that using a wide-angle lens and solid-state charge elements (C, C, D) as another example of the concentration detection sensor allows a wide range to be seen at one location, requiring less movement.

As yet another example of the scanning direction of the density detection sensor 1s, if the conveyance path from the relay tray to the transfer position is long, the sensor may be scanned in a direction perpendicular to the traveling direction while the copy paper is traveling. By simply scanning the copy paper diagonally, the same result can be obtained, simplifying the apparatus. Even in this case, it goes without saying that the Mogami paper in the relay tray always has an image on it (aside from originals whose first side is blank) and can be detected because it is a photographic paper.

As another example of the sensor activation timing, the sensor 161° 16b that detects the presence or absence of paper in the relay tray 9 shown in FIG.
Detects the first copy paper for double-sided copying and transfers the same paper to the relay tray 9.
The scanning time can be shortened by activating the density detection sensor 15 and starting searching for the image position when the image is almost close to the fixed position. This is because the image tUt-pattern is obtained by copying the first side of a plurality of sheets. All you have to do is look for it. In either case, when the number of copies is one, both sides, it is not necessary to operate the sensor 15. Tsutb
, paper presence/absence sensor 16a.

If there is any remaining paper in step 16b, it is sufficient to display the message "Please remove the blank paper in the relay tray", and one sheet of double-sided transfer paper is obtained without any inconvenience. That is, even if the topmost paper on the relay tray 9 is being fed, there is an image. Of course, there is also a method of activating a density detection sensor to detect blank pages due to problems in the image creation process.

Although a relay tray is provided in this embodiment, it is of course possible to use the same method even if the relay tray is not used exclusively for double-sided copying and also serves as a paper feed tray for single-sided copying. Needless to say, the first sheet feeding means for the second side and the second sheet feeding means for the second side are the same sheet feeding means.

Note that the copying machine of the above embodiment can also be provided with a front double feeding detection function as described below. In other words, if there is a slight deviation before the paper rolls due to the feeding of the first side, if the deviation is a few ■, in most cases it can be used as copy paper with a proper image recorded, but if the deviation is 10 ■. In such a case, the image will be severely chipped and the first side will be defective, so in such a case, the length of the copy paper is measured by the copy paper presence/absence detection sensor 13k, and the length of the copy paper is measured and used. Since the size of the copy paper is known in advance, it is compared with this, and if the length of the paper passing through the sensor 13b is deviated due to double feeding, it is too long. In this case, a double feed is displayed, but if there is no problem with paper feeding, the paper is not displayed as a jam, but the paper is allowed to pass through the paper sheet 11 and discharged onto the tray 12, thereby being removed from the normal conveyance system. You can also do it. To do this, the switching guide 8 shown in FIG. 1 should be switched to state C, and when double feeding is detected by the sensor 13h, the switching guide 8 should immediately return to the initial state of the feed position. good.

As described above, in the double-sided image recording apparatus according to the present invention, attention is paid to the point that if double feeding occurs when recording an image on the first side, such double feeding is unlikely to occur when recording an image on the second side. By detecting the presence or absence of an image on the first side of the tuna on the copy paper fed when recording the image on the second side, unnecessary second side images are removed.
This eliminates the need to perform the operation of recording images on both sides, and the image is recorded only on the second side, which prevents the creation of defective mourning paper and the wastage of power consumption. It has various advantages such as not having to feed sheets, and its usefulness is extremely great.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view of a double-sided copying machine according to an embodiment of the present invention, and FIG. , 3rd
The figure is a schematic perspective view showing the configuration for moving the density detection sensor, and Figures 4B), 4B, and 4E are diagrams showing the positional relationship between the placed original and the movement of the density detection sensor. 0) is a diagram showing the state of the document being placed, (b) is a diagram showing the positional relationship between the copy paper used and the density detection sensor, (is a diagram to explain the movement of the immersion detection sensor, and Figure 5 is a diagram showing the position of each detection sensor. This is a diagram to explain the operational relationship between the bago and the jam display section of the copying machine. 1: Draft paper base 2: Disembarkation paper roller 3: Register roller 4: Photosensitive drum 5: Transfer section 6:
Conveyance section 7: Fixing device 8: Switching guide 9: Relay tray 10: Paper feed roller 11: Relay conveyance path 1
2 Nidorei 13a-l: Sensors 14m, 14b, 16m, 16b: Copy paper presence/absence detection sensor 15: Density detection sensor: Sorter 201
:i1x selection button 202:Normal button 203:
) Ray Tan 204: “Bottom 1 button 205:”
206: Copy button 207: White button 208: 0FFz button 301.302: Guide rod 303: Sensor base 303m: Groove
304 Nirakku 305: Motor 306:
Gear 307: / Tensimeter 308: Gear 309: Shaft 310: Sugrocket 311: / Tensimeter 312: Chain 313 Varnish f 4-ket 3
14: Motor 315. 316: Arm 317: Shaft 318: Screw spring 319, 320: Pulley 3
21: Installed cable 322: Cable 3/23: Pulley.

Claims (6)

[Claims] (1) The recording sheet with the first side recorded stored in the storage unit from the first paper feeding unit via the image recording unit is conveyed to the image recording unit by the second paper feeding unit, and the second side is imaged. What is claimed is: 1. A double-sided image recording apparatus that performs recording, characterized in that at least one first side recording degree detection means is disposed in a recording sheet conveyance path from the storage section to the image recording section. (2) The double-sided image recording apparatus according to claim (1), wherein the density detection means is a detection section for stopping the operation of the second paper feeding means. (3) The scope of claims characterized in that the density detection means is a detection unit for stopping the operation of the apparatus after the conveyance of the recording sheet in the conveyance path for second side image recording is completed. 2) The double-sided image one-pack recording device described in 2). (4) The double-sided image recording device according to any one of claims (1) to (3), wherein the storage section includes first and second paper feeding means. (5) Claim (1) characterized in that the density detection means is movable with respect to the first surface of the recording sheet.
The double-sided image recording device described in any one of (4). (6) The double-sided image recording apparatus according to any one of claims (1) to (5), wherein the density detection means includes density reference level switching means.