JP2525676B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention feeds a plurality of originals to an image reading position (hereinafter referred to as a platen) and forms images of the originals on the same surface of the same recording medium. 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 device).

<Prior Art> An image forming apparatus such as a copying machine is equipped with a document feeder,
It is known to copy the images of two originals by arranging them on one side of one recording medium (copy paper), for example, when the originals are continuously fed to the platen for copying.

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

In FIG. 1, reference numeral 100 denotes a copying machine main body, and a document feeder 200 is mounted on a platen 101 serving as an image reading unit.

The original feeding device 200 includes a stacking tray 201 on which a stack of originals S is stacked, a separation unit 202 for separating the originals S ′ from the original stack S on the stacking tray 201 one by one, and the separation unit 202. A transport roller 303 that transports the original S ′ to the platen 101, a sensor 204 that is disposed between the transport roller 203 and the separating unit 202 to detect the original S ′, and the transport roller 2
A full-face belt 205 for setting the document S ′ conveyed from 03 on the platen 101, a discharge roller 206 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 rotates in response to a copy process start signal, separates the lowermost document S 'of the document bundle S by one, and abuts the leading end of the document S' on the transport roller 203 (see FIG. ).

Next, 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 carry roller 203 and the full-face belt 205 are temporarily stopped. (See the same c).

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

Next, the separation unit 202 is rotated to separate the second document S ', and the leading end of the document S' is abutted against the transport roller 203 (see FIG. 3E).

Next, when the second original S 'reaches a predetermined position on the platen 101 by rotating the conveying roller 203 and the full-surface belt 205 forward again, the full-surface belt 205 is stopped (see FIG. 5F).

As a result, two originals S ′ are placed on the platen 101 in a state of being arranged side by side. 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 conveyance roller 203 shown in FIG. 8, the trailing edge of the first document S ′ and the second document S ′. It is difficult to abut the front end, 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. As a result, a gap corresponding to the minimum width of the nip portion or a gap larger than the gap X is generated between the originals S'set on the platen 101, which causes a problem during copying. there were.

For example, as shown in FIG. 9, the size of the document S 'l ₁
If the gap is set to l ₂ and copying is performed on a copy paper of a size twice that of the original S ′, the first original S ′ shifts by l ₂ and protrudes from the image reading area. Area (l ₂ ) of the original S ′ in FIG. ₂ is missing from the copy image, the entire area of the second original S ′ is read and the first and second originals S ′ are not missing. There was a defect that it became uniform.

In other words, since the image information on the document generally has a higher density from its periphery toward the center, the larger the loss width, the easier the information loss. When the missing portion is unevenly generated on the side of the first document, the missing width is large, and there is a risk that information loss of the first document easily occurs.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide the most upstream and most downstream originals when forming images of a plurality of originals on the same surface of the same recording medium. It is an object of the present invention to provide an image forming apparatus capable of reducing the risk of information pitting as much as possible by making the loss of images from a recording medium equal.

<Means for Solving the Problems> Means for solving the above problems and applied to the embodiments described below are image information reading means for reading image information of a document,
In an image forming apparatus that is equipped with a document feeding unit that feeds a document to a reading position of the image information reading unit and forms images of a plurality of documents on the same surface of the same recording medium, the document feeding unit feeds the document to the reading position. Image forming apparatus control in which an interval is provided between a plurality of originals to be sent and the missing widths of the most downstream and the most upstream of the plurality of originals are equalized when an image is formed by the plurality of originals fed to the reading position It is characterized by being equipped with means.

Here, as the image forming apparatus control means, for example, a control means of the document feeding means for controlling a document stop position with respect to the reading position and a timing of starting reading of the image information reading means with respect to the document position are controlled. There is a control means for the image information reading means, a control means for the conveyance means for controlling the conveyance start timing of the recording medium, and the like.

<Operation> According to the above means, for example, when the image information of two originals spaced by a predetermined distance at the reading position is recorded on the same surface of a recording medium having a size twice that of the original, the original is stopped at the reading position. By controlling the position, the reading start timing of the image information reading means, the conveyance start timing of the recording medium, and the like, the uppermost stream and the most downstream image loss width of the two originals are made equal to each other. The width of the first original image missing from the recording medium is reduced to reduce the risk of missing image information of each original.

Hereinafter, an embodiment of the image forming apparatus of the present invention will be described with reference to the drawings.

[First embodiment]

1 to 5 show a first embodiment of the present invention, FIG. 1 is a sectional view showing the outline of a copying machine to which the present invention is applied, and FIGS. 2 (a) to (g) are the same. FIG. 3 is a block diagram of the control unit of the copying machine, FIG. 4 is a flow chart showing the control contents of the control unit, and FIG. 5 is a copy state of the image information of the original. FIG.

In the figure, 10 is a copying machine main body, and a document feeding device 12 as a document feeding means is provided on a platen 11 which is an image reading unit.

The document feeder 12 has a stacking tray 13 for stacking the document bundle S, and a document S ′ from the document bundle S on the stacking tray 13.
Separation unit 14 (conveyor belt 14a, separation belt 14b) for separating the sheets one by one, a substantially U-shaped guide 15 for guiding the separated document S'to the platen 11, and a guide 15 arranged at an appropriate position of this guide 15. A transport roller 16 for transporting the original S'to the platen 11 and a full-face belt 17 for setting the original S'in a predetermined position on the platen 11 are provided.

Here, a semi-circular paper feed roller is provided on the downstream side of the stacking tray 13.
18 and a sensor 19 for detecting the leading edge of the original S '.

Further, the conveyor belt 14a of the separating portion 14 rotates counterclockwise in FIG. 1, and the separator belt 14b also rotates counterclockwise in the vicinity of the conveyor belt 14a.

A sensor 20 for detecting the passage of the document S'is arranged at an appropriate position on the guide 15.

The entire surface belt 17 includes a drive 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 drive rollers 17a. And a conveyor belt 17c wound around the driven roller 17b. And the drive roller 17a
One end of the drive shaft 21a of the drive motor 21 is connected to the drive shaft 17a 'of the drive motor 21.
c runs in the direction of the solid arrow and the direction of the dotted arrow shown in FIG. 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.

A substantially U-shaped guide 23 and a paper discharge roller 24 are provided at the other end of the platen 11 to discharge the document S ′ on the platen 11 onto a paper discharge tray 25 arranged on the conveyor belt 17a. To paper. At an appropriate position of the guide 23, a sensor 26 for detecting the document S 'is arranged.

A reading optical system 27 as image information reading means 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 includes an exposure lamp 27a.
It is composed of a scanning mirror 27b, a lens 27c, and the like. The original is illuminated by the exposure lamp 27a while scanning by the optical scan motor 27d (see FIG. 3), and the reflected light from the original is scanned by the scanning mirror 27b and the lens 27c. It irradiates a photosensitive drum (not shown).

Next, the feeding control of the document S'by the document feeder 12 will be described with reference to FIGS. 2 (a) to 2 (g).

When copying the images of the two originals S'on one side of one recording medium (copy sheet) (in the one-scan mode), first, the feeding roller 18 and the separating unit 14 are rotated,
The first original S'is separated from the lowermost part of the original bundle S, and the leading end of the original S'abuts against the conveying roller 16 to form a predetermined loop (see FIG. 2 (a)). And the transport roller 16,
The full-face belt 17 is rotated in the forward direction to feed the original S ′ toward the platen 11, and when the trailing edge of the original S ′ leaves the feed roller 16, the feed roller 16 and the full-belt 17 are once stopped (see FIG. )reference). After that, the entire surface belt 17 is rotated in the reverse direction and stopped when the rear end of the document S'abuts the conveying roller 16 (see FIG. 2 (c)).

Next, the feeding roller 18 and the separating unit 14 are rotated to separate the second document S ′ from the document bundle S, and the leading end of the document S ′ is abutted against the conveying roller 16 to form a predetermined loop ( Second
See FIG. (D)). Then, the transport roller 16 and the entire surface belt 17 are again rotated in the normal direction, and when the second document S ′ reaches a predetermined position on the platen 11, the entire surface belt 17 is stopped (FIG. 2 (e)).
reference).

Here, the stop position of the entire belt 17, that is, the rear end stop position of the second document S'is changed to the stop position in the normal mode.

In the normal mode, the trailing edge of the document S'passes through the sensor 20 and advances by a predetermined clock so as to stop at the position R ₁ (the position where the reading optical system 27 starts reading) shown in FIG. 2 (e). At that point, the full belt 17 stops. On the other hand, in the one-scan mode, if the gap between the first document S ′ and the second document S ′ is l ₂ , the upstream side of the stop position R _{1 in} the normal mode. l _2/2 rear end of the second sheet of the document S 'to the moved position R ₂ to control the stop position to be located (see FIG. 2 (e)). Thus, the front end of the first sheet of the document S 'will be protruded from the image reading region by l _2/2. Therefore, when reading is performed from the position R ₁ by the reading optical system 27, as shown in FIG.
Missing width of handsome document S 'is l _2/2 respectively.

When the document stop position is controlled in this way, as shown in FIG. 5, the missing widths of the first and second documents S ′ are l ₂ respectively.
/ 2, but this loss is due to the original S'having a low image information density.
There is a loss in the side edge of the document, and the risk of information loss of the document is reduced compared to the case where the defects are concentrated on the first document as in the prior art and the width l ₂ is lost.

Next, the document S'is read (see FIG. 2 (f)), and after this reading is completed, the entire surface belt 17 and the paper discharge roller 24
Is rotated in the normal direction to discharge the document S'on the platen 11 onto the discharge tray 25 (see FIG. 2 (g)).

Next, the control unit, which is the image forming apparatus control means for controlling the feeding as described above, will be explained. As shown in FIG. 3, the control unit 30 is composed of a one-chip microcomputer incorporating ROM and RAM. The control contents shown in FIG. 4 are stored in the ROM portion, and the document feeder 12 is controlled in accordance with the control contents.

The sensors 20, 26 are connected to one input terminal of the control unit 30.
Is connected to the photo interrupter 23, and signals from these sensors 20, 26 and the photo interrupter 23 are input to input the size, the number of sheets S'of the document S'on the platen 11, and the total belt 17.
Is calculated. Further, the other input terminal of the control unit 30 is a mode switch arranged on the operation panel (not shown) of the copying machine body 10 for setting a copying mode.
A copy size switch 32 for setting the size of copy paper as a recording medium is connected.

One-scan mode is set by the mode switch 31 (a mode in which the images of a plurality of originals S ′ are copied on one side of one copy sheet) and the copy size switch 32 is set. The shift amount of the document stop position at the time is calculated.

That is, the control unit 30 calculates the shift amount of the document stop position by performing the following arithmetic processing based on the input signal.

[(Σl ₁ + Σl ₂ ) −l ₃ ] / 2 where Σl ₁ is the total length of the original Σl ₂ is the total spacing between the originals l ₃ is the length of the recording paper.

The drive motor 21 of the document feeder 12 is connected to the output terminal of the controller 30, and controls the drive motor 21 based on the calculated shift amount.

For example, if there are two originals of size A4 (length 210mm), the distance between the originals is 5mm (a value determined by the distance between the nip portion of the transport roller 16), so the total original length Σl ₁ + original spacing The total length Σl ₂ is 210 × 2 + 5 = 425 mm. At this time, if the copy paper size is designated as A3 (length 420 mm) and the magnification is 100%, the shift amount is [425− (420 / 1.00)] / 2 = 2.5 mm. Therefore, if you copy in this mode,
It is possible to obtain a copy in which the second document S'has a gap of 2.5 mm.

If the copy paper is A4 portrait and copying is done at 50% magnification, [425- (210 / 0.50)] / 2 = 2.5 mm, and the document stop position is also shifted by 2.5 mm.

Next, the document feeding means by the control unit 30 will be described with reference to the flowchart of FIG.

First, in step S1, an A4 size document stack S is set on the stacking tray 13 with the image side facing upward.

Next, in step S2, for example, the one-scan mode is set by the mode switch 31 and the A3 size is set by the copy size switch 32.

Next, in step S3, it is determined whether or not there is a copy processing start signal, and if there is a copy start request (YES), the process proceeds to step S4 and it is determined whether the one scan mode or the normal mode. In the case of the normal mode, the process proceeds to step S5 and copying is performed in the normal copy mode.

In the case of the one-scan mode, the process proceeds to step S6 to feed the first document S ', and it is determined in step S7 whether the feeding of the first document S'is completed or not. In the case (YES), the second original S'is fed in step S8. At this time, it feeds to be located in the stop position R ₂ rear stop position shifted upstream by l _2/2 than the stop position R ₁ in the normal mode of handsome document S '.

Next, in step S9, it is determined whether or not the feeding of the second document S'is completed, and if it is completed (in the case of YES), the document S'is read in step S10. At this time, the images of the two originals S'are copied with the same missing width on one side of the A3 copy paper (see FIG. 5).

After the reading is completed, the document S ′ is discharged onto the sheet discharge tray 2 in step S11.
5 is discharged onto the stack tray 13 and the document S ′ is placed on the stacking tray 13 in step S12.
Is determined, and if it remains (YES
In the case of), the process returns to step S6, and the same operation is repeated until the document S'is exhausted.

[Second embodiment]

In the above first embodiment, the same lack width of the original stop position R ₂ with respect to the reading position R ₁ l _2/2 only are shifted upstream one of the document S 'and second sheet of the document S' is However, in this second embodiment, the document stop position is the same as that in the normal mode, but the reading optical system 27 has the same structure. Second reading start position
And it is shifted downstream by l _2/2 as shown in FIG. (E).

That is, when the trailing edge of the second document S ′ reaches the predetermined position of the platen 11, the full belt 17 is stopped. This predetermined position is the R ₁ position like the stop position in the normal mode.
Then, the reading optical system 27 starts scanning to read the document. At this time, the control unit 30 controls the optical scan motor 27d (see FIG. 3) to set the reading start position in the normal mode or in the book ( Reading start position in Book) mode
Change to position R ₃ which is shifted by l ₂ / d downstream from R ₁ .

As a result, similarly to the case of the first embodiment, the missing widths of the first document S'and the second document S'become equal.

[Third embodiment]

In the first embodiment, the document stop position is set with respect to the reading position R ₁ .
The R ₂ is shifted upstream by l _2/2, also the second embodiment in l _2/2 only shifted by one-sheet document S downstream from the reading position R ₁ in the normal mode the reading start position ′ Is made equal to the missing width of the second document S ′, but the document stop position and the reading start position are kept at the position R ₁ as in the normal mode, and the registration clutch of the recording paper conveyance system is used. 33 and delayed by l _2/2 by the control unit 30 a timing for driving some similar effects.

That is, as shown in FIG. 6, the transfer timing of the first sheet image information 34a ₁ and the second sheet image information 34a ₂ of the photosensitive drum 34 and the recording sheet 35 is controlled by the control unit 30 by controlling the registration clutch 33. by slowing distance l _2/2 (by starting slowly conveying the recording paper 35), it becomes possible to equalize the missing width of one page of the document S 'and second sheet of the document S' .

Note that one piece of the image information 34a ₁ on the photosensitive drum 34, a shift amount of the second sheet image information 34a ₂ and the recording sheet 35 is when the magnification copying is l _2/2, of the variable magnification copy case is (l _2/2) × magnification. This is because the image information 34a on the photoconductor drum 34 is an already scaled image, and it is necessary to multiply the shift amount of the recording paper 35.

[Other Examples]

In the above embodiment, the document feeding device 12 is used as the stacking tray 13
Although the apparatus in which the paper discharge tray 25 and the paper discharge tray 25 are separately provided is shown, the apparatus in which the fed document S ′ is returned to the stacking tray 13 may be used.

Further, although the case where two originals S ′ are fed and copied on the platen 11 is shown, three or four originals S ′ may be fed to the platen 11 for copying.

Further, when the images of a plurality of originals S ′ are formed on the same side of the same recording medium, only one side (front side) of the recording medium is shown (one-sided copying). It can also be applied to double-sided copying in which the front and back are reversed and images of a plurality of originals S ′ are formed on the back side.

Also, the case where the present embodiment is applied to a copying machine has been described.
Of course, it can be applied to a laser beam printer or an image reader (reading device).

<Effects of the Invention> As described above, according to the present invention, when images of a plurality of originals spaced at a predetermined position at the reading position are formed on the same surface of the same recording medium, the plurality of originals are formed. Since the image forming apparatus control means for equalizing the image loss widths of the uppermost stream and the lowermost stream of the above is equipped, the loss of each original image from the recording medium is reduced, and the risk of information loss is minimized. You can

[Brief description of drawings]

1 to 4 show an embodiment of the present invention. FIG. 1 is a sectional view showing the outline of a copying machine, and FIGS. 2 (a) to 2 (g) are document feeders of the copying machine. FIG. 3 is a block diagram of the control unit of the copying machine, FIG. 4 is a flowchart showing the control contents of the control unit, and FIG. 5 is an explanatory diagram showing the copying state. FIG. 6 is an explanatory view showing another embodiment (third embodiment), and FIG. 7 (a).
8 to 9 show a prior art, FIG. 7 (a) is a schematic sectional view, FIGS. 7 (b) to 7 (h) are operation explanatory diagrams, and FIG. FIG. 9 is an enlarged cross-sectional view of the nip portion of the conveying roller, and FIG. 9 is an explanatory diagram showing a state where image information is missing from the recording medium. 10 is a copy machine book, 11 is a platen (image reading position), 12 is a document feeding unit (document feeding device), 13 is a stacking tray, 14 is a separating unit, 16 is a conveying roller, 17 is a full belt, and 18 is a feeding unit. Paper rollers, 19 and 20 are sensors, 21 is a drive motor, 22 is a clock plate, 23 is a photo interrupter, 27 is an image information reading means (reading optical system), 27d is an optical scan motor, and 30 is an image forming apparatus control means ( Control unit), 33 is a registration clutch, and S'is a document.

Claims (7)

(57) [Claims] 1. An image information reading means for reading image information of an original and an original feeding means for feeding the original to a reading position of the image information reading means, and images of a plurality of originals are recorded in the same manner. In an image forming apparatus that forms on the same surface of a medium, a space is provided between a plurality of originals that are fed to the reading position, and the plurality of originals that are fed to the reading position are used to form an image. An image forming apparatus equipped with image forming apparatus control means for making the missing widths of the most downstream and the most upstream of a document equal. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus control unit is a control unit of the document feeding unit that controls a document stop position with respect to the reading position. 3. The image forming apparatus according to claim 2, wherein the document stop position with respect to the reading position is on the upstream side by half the document interval. 4. The image forming apparatus control means is a control means of the image information reading means for controlling a reading start timing of the image information reading means with respect to a document position. The image forming apparatus described. 5. The image forming apparatus according to claim 4, wherein the reading start position of the image information reading control means is located on the downstream side by half the document interval. 6. The image forming apparatus according to claim 1, wherein the image forming apparatus control means is a control means for controlling a transfer timing of the recording medium. 7. The image forming apparatus according to claim 6, wherein the transfer timing of the recording medium is delayed by half the document interval.