JPH0675217B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus such as a copying machine, a printing machine, a laser beam printer or an image reader (reading apparatus), and more specifically, it reads an original by an original feeding apparatus. The present invention relates to a device in which a plurality of sheets are fed to a position (hereinafter referred to as a platen) and the image information of the original is formed on the same surface of the same recording medium without the image information of the original being lost.

<Prior Art> When an image forming apparatus such as a copying machine is equipped with a document feeding device and a document is automatically continuously fed to a platen for copying,
For example, images of two originals are recorded on one recording medium (copy paper).
It is known to line up on one side of and copy.

FIG. 7 (a) shows an example of an image forming apparatus for performing the above-mentioned copying.

In the figure, 100 is a copying machine main body, and a document feeding device 200 is mounted on a platen 101 which is an image reading unit.

The document feeding device 200 includes a stacking tray 201 on which a stack of documents S is stacked and a document S ′ (see FIGS. 7B to 7H) separated from the stack of documents S on the stacking tray 201 one by one. Separating section 202 and document S ′ separated by this separating section 202
To the platen 101, a sensor 204 disposed between the transport roller 203 and the separating section 202 for detecting the document S ′, and a document S ′ transported from the transport roller 203 on the platen 101. A full-face belt 205 to be set on, a discharge roller 207 for discharging the document S ′ on the platen 101 onto a discharge tray 206, and the like are provided.

In the image forming apparatus, first, the document stack S is set with the image surface facing upward (see FIG. 7A).

Next, the separation unit 202 is rotated by the copy processing start signal,
The lowermost original S'of the original stack S is separated into one sheet, and the leading end of the original S'abuts against the conveying roller 203 (FIG. 2 (b)).
reference).

Then, the transport roller 203 and the full-face belt 205 are rotated in the forward direction to feed the document S ′ toward the platen 101, and when the trailing edge of the document S ′ leaves the transport roller 203, the transport roller 203 and the full-face belt 205 are temporarily stopped ( (See (c)).

Then, the full-face belt 205 is rotated in the reverse direction and stopped when the rear end of the document S'abuts on the conveying roller 203 (see FIG. 3D).

Next, the separating unit 202 is rotated to separate the second original S ', and the leading end of the original S'abuts the conveying roller 203 (see FIG. 8E).

Next, when the conveying roller 203 and the full-face belt 205 are again rotated in the normal direction to reach the predetermined position of the platen 101 for the second document S ', the full-face belt 205 is stopped (see (f) in the figure).

As a result, two originals S ′ are placed on the platen 101 in parallel. After that, when the image of the original S'is read (see FIG. 9G), the image of the two originals S'is copied on one side of one copy sheet.

After the reading is completed, the entire surface belt 205 and the paper discharge roller 207 are normally rotated to discharge the document S ′ on the platen 101 onto the paper discharge tray 206 (see FIG. 6H).

<Problems to be Solved by the Invention> However, as is clear from the enlarged view of the nip portion of the conveying roller 203 shown in FIG. 8, the rear end of the first document S'and the front end of the second document S '. It is difficult to abut and, and a gap corresponding to the width X of the nip portion is generated.

Further, in terms of component accuracy, it is difficult to make the conveyance speed of the conveyance roller 203 and the conveyance speed of the full-face belt 205 the same. Therefore, the conveyance speed of the whole-face belt 205 on the downstream side is conveyed by the conveyance roller 203 on the upstream side. It is set slightly faster than the speed.

Therefore, between the documents S'set on the platen 101, there is a gap X corresponding to the width of the nip portion or a gap larger than the gap X, which causes a problem during copying. .

For example, if the size of the original S'is L and the gap is l ₂ as shown in FIG. 9, when copying to a copy paper of a size twice as large as the original S ', the first original S'will be l. _It shifts by ₂ minutes and extends out of the image reading area.
There was a defect that the shaded area (l ₂ ) of the minute was missing from the copy image.

The present invention has been made to solve the above-mentioned problems of the prior art. An object of the present invention is to form an image of a document from a recording medium when forming images of a plurality of documents on the same surface of the same recording medium. It is an object of the present invention to provide an image forming apparatus that does not cause any trouble such as missing.

<Means for Solving the Problems> Means for solving the above problems and applied to the embodiments described below are reading means for reading image information of an original, means for sending the original to a reading position of the reading means, and its means. In an image forming apparatus equipped with a document feeding unit having a document feeding unit on the upstream side and forming images of a plurality of documents on the same surface of the same recording medium, the document is fed to the reading position of the reading unit. A control means is provided for controlling the document feeding means so that the trailing edge of the leading document to be fed and the leading edge of the following document overlap in advance, and these documents have reached the reading position. It is characterized in that the upstream-side document feeding means is configured to have a slower feeding speed than the downstream-side document feeding means so that the overlap amount becomes almost zero due to a speed difference.

Further, the control means is configured to detect the size of the original document and set the overlap amount according to the size of the original document.

<Operation> According to the above means, for example, when the image information of two originals is recorded on the same surface of the recording medium having a size twice that of the originals, the control means controls the original feeding method of the original feeding means. So that the two originals are lined up at the reading position without a gap.

Therefore, the image information of the original is formed so as not to be lost from the recording medium.

<Embodiment> An embodiment of the image forming apparatus of the present invention will be described below with reference to the drawings.

[First embodiment]

1 to 6 (a) to (f) show an embodiment of the present invention, and FIG. 1 is a sectional view showing a schematic solution of a copying machine, and FIG.
(A) to (f) are explanatory views of the operation of the document feeder of the copying machine, FIG. 3 is a block diagram of the control section of the copying machine, and FIG. 4 is a flowchart showing the control contents of the control section. FIG. 5 is an explanatory view showing a copy state of image information of an original, FIG. 6 (a) is an explanatory view showing a developed positional relationship among a sensor, a conveyance roller and a full-face belt, and FIGS. 10A is an explanatory diagram for explaining the process of conveying the document S ′.

In FIG. 1, reference numeral 10 is a main body of a copying machine, and a document feeding device 12 as a document feeding means is provided on a platen 11 which is a reading position.

The document feeder 12 includes a stacking tray 13 on which a stack of documents S is stacked, and a separating unit 14 (conveying belt 14a, separation belt 14b) for separating the documents S'from the stack of documents S on the stacking tray 13 one by one. And a substantially U-shaped guide 15 for guiding the separated document S ′ to one end side of the platen 11 (left side in FIG. 1),
The guide roller 15 is arranged at an appropriate position to convey the original S ′ to the platen 11, and the original S ′ to the platen 11.
Full-scale belt as a conveyor belt to be set at the specified position
It is equipped with 17 mag.

A semi-circular paper feed roller 18 and a sensor 19 for detecting the leading edge of the document S'are arranged on the downstream side of the stack tray 13 in the document transport direction.

Further, the conveyor belt 14a of the separating section 14 rotates counterclockwise in FIG. 1, and the separating belt 14b is the conveyor belt 14a.
Similarly, it rotates counterclockwise in the vicinity of.

A standby portion 15a bulging outward is provided in the vicinity of the conveying roller 16 of the guide 15 (Fig. 2 (b),
(See (c)). During the waiting unit 15a to overlap and 'rear portion and second sheet of document S _2' of the tip portion of the first sheet of the original S _1, temporarily rear end of the first sheet of the document S ₁ ' In addition to waiting, the leading edge of the second document S ₂ ′ is conveyed until it hits the feeding roller 16 without being obstructed by the trailing edge of the _first document S ₁ ′. A sensor 20 for detecting the passage of the document S'is arranged at an appropriate position on the guide portion 15.

The entire surface belt 17 includes a driving roller 17a arranged on one end side of the platen 11 (left side in FIG. 1), a driven roller 17b arranged on the other end side of the platen 11 (right side in FIG. 1), and these driving rollers. It is composed of a conveyor belt 17c wound between a driven roller 17b and a driven roller 17b. And drive roller 1
One end of the drive shaft 21a of the drive motor 21 is connected to the drive shaft 17a 'of 7a.
c runs in the direction of the solid arrow and the direction of the dotted arrow shown in FIG.

The conveying speed of the full-face belt 17c is set to be slightly higher than that of the conveying roller 16. Generally, it is set around 3% faster. This is done by the transport rollers
When the speeds of 16 and the full belt 17c are reversed, the conveyance roller 16
This is to prevent the slack of the document S'between the full-scale belt 17c and the original and the conveyance problem to occur.

A clock plate 22 is connected to the other end of the drive shaft 21a, and a photo interrupter 23 is arranged close to the clock plate 22. The photo interrupter 23 counts the number of slits provided in the clock plate 22 to control the movement amount of the conveyor belt 17c. Also drive motor 2
Since the driving force of 1 is also transmitted to the transport roller 16, the size (length in the transport direction) of the document S ′ transported by the transport roller 16 between the guides 15 is determined by counting the slits of the sensor 20 and the clock plate 22. It can also be detected.

On the other end of the platen 11, a guide having a substantially U shape is provided.
Equipped with 23 and a paper discharge roller 24, the document S'on the platen 11 is discharged onto a paper discharge tray 25 arranged on the conveyor belt 17a. A sensor 26 for detecting the document S'is arranged at an appropriate position on the guide 23.

A reading optical system 27 as a reading unit for reading an image of the original S ′ on the platen 11 is arranged in the copying machine body 10. The reading optical system 27 is composed of an exposure lamp 27a, a scanning mirror 27b, a lens 27c, and the like, and the exposure lamp 2 is scanned by an optical scan motor 27d (see FIG. 3).
Illuminate the original with 7a and scan the reflected light from the original with the scanning mirror 27
b, the lens 27c irradiates a photosensitive drum (not shown).

A control unit 30 (see FIG. 3) as a control means for controlling the document feeding device 12 and the reading optical system 27 is composed of a CPU, a ROM, a RAM and the like, and the control portion shown in FIG. The contents are stored.

The control unit 30 includes the sensors 20, 26 and the photo interrupter 23.
Are connected. The control unit 30 inputs signals from these sensors 20 and 26 and the photo interrupter 23, and, for example, the standby unit 15a causes the trailing edge of the _first document S ₁ ′ and the second document S ₁ ′.
_The document feeding device 12 is controlled so that the leading end of 2'is temporarily overlapped and then the document S'is transported so that the overlap amount becomes substantially zero during the transportation to the platen 11.

Further, the control unit 30 calculates the overlap amount based on the length of the document S '(conveyance direction length) detected by the sensor 20 and the photo interrupter 23, and based on this overlap amount, the document feeding device as described above. Control 12

In addition, the control unit 30 includes a mode switch 31 for setting a copy mode arranged on an operation panel (not shown) of the copying machine body 10.
And a copy paper size switch 32 for setting the size of copy paper as a recording medium are connected.

Next, the operation of the above embodiment will be described with reference to FIGS. 4 and 2A to 2F.

First, in step S10, the document stack S is set on the stacking tray 13 with the image side facing upward (see FIG. 1).

Then, in step S11, the mode switch 31 is used to set the one-scan mode (a mode in which the images of a plurality of originals S'are copied onto one side of one copy sheet). Further, the copy paper size switch 32 is used to set the copy paper size and the copy magnification. Here, for example, the size of the original S ′ is A size, the size of copy paper is A3, and the copy magnification is the same size.

After that, when a copy start button (not shown) is pressed, it is determined in step S12 whether the copy start button is on or off. If it is on, the process proceeds to step S13.

In step S13, the separation unit 14 and the paper feed roller 18 rotate,
The first original S ₁ ′ is separated from the bottom of the original stack S, and the leading end of the original S ₁ ′ is abutted against the conveying roller 16 to form a predetermined loop (see FIG. 2A).

In step S14, the leading edge of the _first document S ₁ ′ is conveyed by the conveyance roller 16
It is determined whether or not the sheet has hit the sheet. If the sheet has hit the sheet, the process proceeds to step S15, while the separating unit 14 and the sheet feeding roller 18
Stops.

In step S15, the transport roller 16 and the entire surface belt 17 are rotated in the normal direction to transport the _first document S ₁ ′ toward the platen 11. Then, in step S16, the trailing edge of the _first document S ₁ ′ is set to the sensor 20.
However, the size of the _first document S ₁ ′ is detected by the photo interrupter 23 and the sensor 20 in this conveyance process.
The overlap amount is calculated based on this. Then, it is determined whether or not the trailing edge of the _first document S ₁ ′ has advanced from the sensor 20 by a predetermined amount f ₁ .

If the trailing edge of the _first document S ₁ ′ has advanced by a predetermined amount f ₁ (YES), the process proceeds to step S17 to temporarily stop the conveying roller 16 and the entire belt 17 (FIG. 2 (b). )reference).

Here, as shown in FIG. 2B, the sensor 20 and the conveyance roller
If the distance to the nip of 16 is l ₁ , the first document
The rear end of S ₁ ′ is on standby upstream of the nip portion of the conveying roller 16 by l ₁ −f _{1 in the} original conveying direction.

Next, in step S18, the separation unit 14 and the paper feed roller 18
Rotates to separate the second document S ₂ ′, and step S19
Then, the front end of the second original S ₂ ′ is brought into contact with the conveying roller 16 to form a predetermined loop (see FIG. 2 (c)).

Step S19 conveying the leading edge of the second sheet of the document S ₂ 'by rollers 16
If it hits, while moving to step S20,
The separation unit 14 and the paper feed roller 18 are stopped.

Here, the second document S ₂ ′ is conveyed while the rear edge of the _first document S ₁ ′ is being seen, but the _first document S ₁ ′ is conveyed.
The trailing edge of S ₁ ′ is located inside the standby portion 15 a that bulges outward due to the elastic force of the document itself and does not block the passage in the guide 15, so the leading edge of the second document S ₂ ′. The part enters the guide 15 and hits the conveyance roller 16 without any trouble.

In this way, the rear end of the _first document S ₁ ′ and the front end of the second document S ′ overlap by a predetermined amount (l ₁ −f ₁ ) and stand by.

In step S20, the transport roller 16 and the entire surface belt 17 are rotated in the forward direction, and the first document S ₁ ′ and the second document S ₂ ′ are placed on the platen 11
Transport in the direction.

Then the rear end of the second sheet of the document S ₂ 'are sensors in Step S21 2
Whether 0 has passed through 0 and has advanced by a predetermined amount f ₂ , that is, as shown in FIG. 2D, the trailing edge of the second document S ₂ ′ is at the platen.
11 It is determined whether or not the process has advanced to the upper position, and if it has (YES), the process proceeds to step S22 and the conveyance roller
16 、 Full belt 17 stops.

Here, the first document S ₁ ′ and the second document S ₂ ′ are held while the document S ′ is sandwiched between a pair of rollers forming the transport roller 16 (while being held by the transport roller 16). (While it is moving) is conveyed at the conveyance speed of the conveyance roller 16,
When exiting from 16, the transfer speed of the full belt 17 (transfer roller 16
The speed is about 3% faster than that).

Therefore, the first document S ₁ ′ is conveyed along with the second document S ₂ ′ by the length of the overlap length (l ₁ −f ₁ ). After being conveyed for a length, the entire surface belt 17 conveys it at a speed faster than that of the second document S ₂ ′, and in the process of being conveyed to the platen 11, the overlap becomes nearly zero, and on the platen 11, the overlap becomes almost zero. The first document S ₁ ′ and the second document S ₂ ′ are set in a state in which they are lined up without a gap.

Then one of the document S ₁ 'and second sheet of the document S in step S23
₂ 'image information is read in, the image information is copied on one side of the copy sheet of A3 (see FIG. 2 (e)).

After the reading is completed, in step S24, the entire belt 17 and the paper discharge roller 24 are normally rotated to discharge the two originals S ₁ ′ and S ₂ ′ on the platen 11 onto the paper discharge tray 25 (see FIG. 2 ( See h)).

Next, at step S25, it is judged whether or not the document S'is left on the stacking tray 13, and if it is left (YES), the process returns to step S13 and the same operation is repeated until the document S'is exhausted. .

In this way, as shown in FIG. 5, the images of two A4 size originals S'can be copied onto one side of an A3 size copy sheet without loss.

Next, with reference to FIGS. 6 (a) to 6 (d), the point that the overlap amount between the _first document S ₁ ′ and the second document S ₂ ′ becomes almost zero during the document conveyance process will be described. This will be described in more detail.

FIG. 6 (a) shows the sensor 20, the conveying roller 16, and the entire surface belt 17.
3B is an expanded view showing the positional relationship of FIG. 3B, and FIGS. 4B to 4D are explanatory views for explaining the conveyance process of the document S ′.

As described above, the full-face belt 17 is set so as to convey the document S'at about 3% faster than the conveying roller 16.
Further, the force (conveying force of the conveying roller 16) for nipping the document S ′ between the pair of rollers forming the conveying roller 16 is the whole belt.
The force is set to be stronger than the force (conveying force of the full-face belt 17) for nipping and conveying the document between the platen 11 and the platen 11. While the document S ′ is nipped by the conveying roller 16, the speed of the document S ′ of the conveying roller 16 is increased. Will be transported in.

As shown in FIG. 2B, considering the state where the trailing edge of the _first document S ₁ ′ and the leading edge of the second document S ₂ ′ overlap, the conveying roller 16 and the entire surface in this state are considered. Even if the belt 17 rotates in the forward direction, the first document S ₁ ′ is advanced even if it overlaps the entire surface of the belt 17 until it advances through the overlap and leaves the transport roller 16 (see FIG. 7C). It advances at the speed of the transport roller 16.

Then, when the first document S ₁ ′ passes through the transport roller 16, it is transported at the transport speed of the entire surface belt 17. At this time, since the second document S ₂ ′ is still held by the transport roller 16,
It is carried at the carrying speed of the carrying roller 16. That is, the first original S ₁ ′ and the second original S ′ are conveyed with a speed difference between the full-face belt 17 and the conveying roller 16. This state continues until the second document S ₂ ′ comes out of the transport roller 16.

In the meantime, the distance that the _first document S ₁ ′ and the second document S ₂ ′ have advanced is based on the document length (L) and the overlap amount (l ₁ −f ₁ ).
The value is L- (l ₁ −f ₁ ) obtained by subtracting (see (d) of the same figure).

However, since the overlap amount (l ₁ −f ₁ ) is extremely smaller than the length L of the original S ′, the distance traveled by the first and second originals S ₂ ′ is the length of the original S ′. It can be approximated to L. Then, during the conveyance, the first original S ₁ ′ is advanced by a distance advanced by 3%, that is, L × 0.03, compared with the second original S ₂ ′.

Therefore, if L × 0.03 is set as the overlap amount, the first original S ₁ ′ and the second original S ₂ ′ can be arranged on the platen 11 without any gap.

Here, since L is the length of the document S ′, it can be seen that the set value of the overlap amount is determined by the length of the document S ′.

For example, when the document size is A4, the overlap amount is 210 mm × 0.03 = 6.3 mm.

When the document size is B5, it is 182 x 0.03 = 5.46 mm.

In the case of the document size LTR, it is 216 x 0.03 = 6.48 mm.

Next, the relationship between the document size and the overlap amount will be described in more detail.

The number of slits of the clock plate 22 from the start of driving the conveying roller 16 and the entire surface belt 17 in step S15 to the time when the trailing edge of the _first document S ₁ ′ passes through the sensor 20 in step S16 is determined by the photo interrupter. The original length L is detected by counting at 23.

When the document length L is detected, the overlap amount (L × 0.03) is obtained as described above, and therefore the conveyance roller 16 stops the trailing edge of the _first document S ₁ ′ by L × 0.03. Just do it.

For that purpose, since the distance from the sensor 20 to the nip portion of the transport roller 16 is l ₁ , the remaining distance obtained by subtracting the overlap amount (L × 0.03) from this distance l ₁ , that is, the sensor 20 It is sufficient to send only a predetermined amount f ₁ .

This predetermined amount f ₁ can be expressed as f ₁ = l ₁ − (L × 0.03).

Since l ₁ is a constant value determined by the document feeder 12, f ₁ changes only depending on the size of the document S ′.

For example, the distance l ₁ between the sensor 20 and the nip of the transport roller 16
Is 12 mm, when the document size is A4, f ₁ is f ₁ = 12− (210 × 0.03) = 5.7 mm, and after the trailing edge of the _first document S ₁ ′ passes through the sensor 20, It is enough to stop at the stage of 5.7 mm feeding.

When the original size is B5, f ₁ = 12− (182 × 0.03) = 6.54mm, and when the original size is LTR, f ₁ = 12− (216 × 0.03) = 5.52mm. .

After the first document S ₁ ′ passes through the sensor 20, the transport roller 16
It is possible to change the overlap amount by changing f ₁ according to the size of the document S ′ up to the nip portion of (the overlap amount can be changed according to the size of the document S ′. Therefore, it is possible to eliminate the loss of image information even when the document size is variously changed.

[Other Examples]

In the present embodiment, the type of device in which the stacking tray 13 and the discharge tray 25 are separately provided as the document feeding device 12 is shown, but a device of the type in which the fed document S ′ is returned to the stacking tray 13 again is also shown. Good.

Further, although the case where one original S'is fed and copied on the platen 11 is shown, three or four originals S'are fed to the platen 11.
You may send it to 11 for copying.

Further, when the images of a plurality of originals S ′ are formed on the same surface of the same recording medium, only one surface (front surface) of the recording medium is shown, but the recording medium is turned upside down inside the printer,
The present invention can also be applied to double-sided copying in which images of a plurality of documents S ′ are formed on the back side.

Further, although the case where the present embodiment is applied to a copying machine is shown, it goes without saying that the present invention can also be applied to a laser beam printer, an image reader (reading device), or the like.

<Advantages of the Invention> As described above, according to the present invention, the trailing edge of the leading original fed to the reading position of the reading means and the leading edge of the succeeding original are overlapped in advance, and these originals are overlapped. When the sheet reaches the reading position, the leading original is fed faster so that the overlap amount becomes almost zero to provide a speed difference, so that a plurality of originals can be fed to the reading position with almost no gap. Therefore, when images of a plurality of originals are formed on the same surface of the same recording medium, there is no problem that the images of the originals are missing from the recording medium.

Further, when the size of the original is detected and the overlap amount is set according to the size of the original, it is possible to prevent the loss of image information even if the size of the original is changed. it can.

[Brief description of drawings]

1 to 6 (a) to (d) show an embodiment of the present invention, and FIG. 1 is a sectional view showing a schematic solution of a copying machine.
(A) to (f) are explanatory views of the operation of the document feeder of the copying machine, FIG. 3 is a block diagram of the control section of the copying machine, and FIG. 4 is a flowchart showing the control contents of the control section. FIG. 5 is an explanatory view showing a copying state, and FIG. 6 (a) is an explanatory view showing the positional relationship among the sensor 20, the conveying roller 16 and the entire surface belt 17 in a developed manner, and FIGS. FIG. 7D is an explanatory view for explaining the process of conveying the original S ′, FIGS. 7A to 7H show a prior art, and FIGS. 7A to 7H are operations. Explanatory drawing, FIG. 8 is an enlarged sectional view of the nip portion of the conveying roller, and FIG. 9 is an explanatory view showing a state where image information is missing from the recording medium. 10 is a copying machine main body, 11 is an image reading position, 12 is a document feeding unit (document feeding device), 13 is a stacking tray, 14 is a separating unit (conveying belts 14a and 14b), 15 is a guide, and 16 is conveying. Rollers, 17 full-face belt, 18 paper feed roller, 19 and 20 sensor, 21 drive motor, 21a drive shaft, 22 clock plate, 2
3 is a photo interrupter, 24 is a paper discharge roller, 25 is a paper discharge tray, 26 is a sensor, 27 is a reading optical system, 30 is a control unit (control means), 31 is a mode switch, 32 is a copy paper size switch, and S ′. Is the original, S ₁ ′ is the first original, and S ₂ ′ is the second original.

Claims (2)

[Claims] 1. A plurality of document readers, each comprising: a reading unit for reading image information of a document; and a document feeding unit having a unit for feeding a document to a reading position of the reading unit and a document feeding unit upstream thereof. In an image forming apparatus that forms images of a single document on the same surface of the same recording medium, the trailing edge of the leading document fed to the reading position of the reading means and the leading edge of the document following the leading edge of the document are overlapped in advance. A control means for controlling the document feeding means so as to wrap is provided, and further, when the documents reach the reading position, the document feeding means on the upstream side is arranged so that the overlap amount becomes almost zero due to the speed difference. Is an image forming apparatus characterized in that the feeding speed is slower than that of the document feeding means on the downstream side. 2. The control means is configured to detect the size of the original document and set the overlap amount in accordance with the size of the original document. Image forming device.