JP2000305418A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high performance image forming device making the time required from paper feeding to the paper discharging for a sheet shortened. SOLUTION: This image forming device is made possible to shorten the time required from the paper feeding to the paper discharging by letting the first sheet of the successive paper feeding fed from the paper feeding device (ASF) 15 whose paper feeding distance is short, the subsequent second sheet is fed from the paper feeding device 30 whose paper feeding distance is long (cassette), and while maintaining the specified time between the preceding sheet and the subsequent sheet regardless of making paper feed from either paper feeding device, the unnecessary time for the recording work is saved, and it is possible that the optimum paper feed timing is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a facsimile machine, a copying machine, a printer, and the like, which forms a fixed cut sheet from a plurality of paper feeding means to form an image. is there.

[0002]

2. Description of the Related Art Conventionally, as this type of image forming apparatus,
For example, there are a facsimile machine and a multifunction peripheral. FIG.
1 is a schematic cross-sectional view of a facsimile apparatus which is an example of a conventional image forming apparatus. A conventional facsimile machine will be described with reference to FIG.

In a conventional facsimile apparatus, an optical reading system 103 for reading image information of a document and a recording system 104 having image forming means for forming an image on the surface of a sheet.
And an operation panel 105 for performing various operations, and an electrical unit for operating these.

An optical reading system 103 guides an original when the original is set in order to smoothly feed the original to an automatic document feeder (ADF) which separates and feeds the original one by one. A paper discharge tray 110 is provided, which also serves as a document tray for the purpose of performing printing and discharges recorded sheets.

The optical reading system 103 includes an operation panel 10
5 is provided on the back side. In order to make it easy for the user to set a document and to reduce the size of the apparatus, the document is set on the upper part of the operation panel 105. The discharge tray 110 also serving as a document tray is operated by the operation panel 105.
It is provided above.

Documents conveyed one by one by an ADF device or the like are read in image information by an optical reading system 103 provided on the back side of the operation panel 105, and then read in front of the device on the front side of the operation panel 105 (FIG. 4). Left).

On the other hand, the recording system 104 includes a universal sheet feeding device 115 for setting the width of the slider 115c in accordance with the sheet width, and a cassette sheet feeding device 130 having a large sheet storage capacity.

The universal sheet feeding device 115 is provided with a sheet feeding tray 108 for holding a sheet bundle, in which a user can easily set the sheet bundle. Paper feed tray 108
Are separated and fed one by one.

Sheets separated and fed one by one from either the universal paper feeder 115 or the cassette paper feeder 130 are fed into the main body of the apparatus, where they are fed to an electrophotographic image forming means. After the recording system 104 has a toner image formed on the surface of the sheet and the recording is completed, the sheet is discharged outside the apparatus.

[0010] The recorded sheet discharged outside the machine is
The paper is stacked on the paper discharge tray 110. The output tray 110 is
It is composed of a mold material for loading recorded sheets.

The conventional facsimile apparatus described above is provided with a plurality of paper feeders such as a universal paper feeder and a cassette paper feeder, and when a plurality of sheets of different sizes are stored in the plurality of paper feeders. Then, a sheet corresponding to the size of the document on the transmission side from which the image information is read is fed and recorded.

On the other hand, when sheets of the same size are stored in a plurality of paper feeders, a paper feed priority is set in advance as to which paper feeder among the plurality of paper feeders is to be preferentially fed. In advance, the sheet is fed from the set priority sheet feeding device and recording is performed.

When the sheets set in the preset high-priority sheet feeding device are used up and the sheets are exhausted, the sheets are fed from another lower-priority sheet feeding device. And recorded.

A paper feeder that feeds paper preferentially among a plurality of paper feeders is usually set to a cassette paper feeder having a large sheet storage capacity, for example, a cassette that can store many sheets. Many. This is to prevent the sheets from being lost immediately and to reduce the number of maintenance operations for replenishing the sheets.

Therefore, a sheet feeding device having a small sheet storage capacity is often used as a so-called spare sheet feeding port.

[0016]

As described above, a cassette sheet feeder or the like having a large sheet storage capacity set preferentially for sheet feeding is often laid out relatively below the main body of the apparatus.

Further, since the sheet feeding device having a large sheet storage capacity, such as a cassette sheet feeding device, is arranged at a relatively lower portion of the apparatus main body, the recording is performed in comparison with the case where the sheet is fed from another sheet feeding device. The transport path (paper path) to the system was long, and the paper feeding distance was long.

For this reason, extra time is required from when the CPU issues a recording command to when the sheet is fed and when the fed sheet is conveyed to the recording system and becomes recordable.

Here, regarding the second and subsequent sheets of the continuous sheet feeding during a series of continuous printing operations, the sheet feeding operation of the next sheet is completed before the printing of the previously fed sheet is completely completed. Can be devised. Thus, regardless of which sheet feeding device feeds the sheet, by adjusting the timing of starting the sheet feeding operation, there is no difference in the time required for the printing operation for the second and subsequent sheets.

However, in the case of feeding the first sheet of the continuous paper feeding during a series of continuous printing operations, or in the case of feeding only one sheet alone, the feeding due to the difference in the paper path length up to the printing system. The difference in paper time directly affected the total time from paper feeding to paper discharging.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a high-performance image forming apparatus capable of shortening the time from sheet feeding to sheet discharging. To provide.

[0022]

According to the present invention, a plurality of sheet feeding means capable of storing sheets of the same size are provided. And an image forming unit for forming an image on a sheet fed from the plurality of sheet feeding units, wherein the plurality of sheet feeding units store sheets of the same size, When the sheet is fed, the sheet is fed by the sheet feeding unit having the shortest sheet feeding distance to the image forming unit among the plurality of sheet feeding units.

When continuously feeding sheets of the same size,
It is preferable that at least the first sheet is fed by a feeding unit having a shortest feeding distance to the image forming unit.

It is preferable that the subsequent sheets are fed by a sheet feeding means different from the sheet feeding means for feeding at least the first sheet.

It is preferable that the sheet feeding means for feeding at least the first sheet has a small sheet storage capacity, and the sheet feeding means for feeding subsequent sheets preferably has a large sheet storage capacity.

A facsimile machine is preferred.

Therefore, when the first sheet of the continuous sheet feeding is fed or when only one sheet is fed alone, up to the inner image forming means of a plurality of sheet feeding means containing sheets of the same size. Since the sheet is fed by the sheet feeding means having a short sheet feeding distance, the time required from sheet feeding to sheet discharging can be reduced.

[0028]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The materials, shapes, relative arrangements, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

With reference to FIGS. 1 to 3, a facsimile machine as an example of the image forming apparatus according to the embodiment will be specifically described.

FIG. 1 is a perspective view showing a facsimile apparatus according to the embodiment, FIG. 2 is a schematic sectional view showing the facsimile apparatus according to the embodiment, and FIG. 3 is a block diagram of recording control of the facsimile apparatus according to the embodiment. FIG.

First, the overall configuration of a facsimile machine will be schematically described with reference to FIGS. 1 is an apparatus main body. Reference numeral 2 denotes a cartridge cover shared by a document table and configured to be able to stack a plurality of documents.

Reference numeral 3 denotes an optical reading system for reading image information of a document. Reference numeral 4 denotes a recording system including a laser beam printer that forms an image with a toner on a sheet made of paper or a synthetic resin and records the image. 5 is a front surface of the apparatus main body 1 (FIG. 2).
(Left side) Operation panel provided at the top.

Reference numeral 8 denotes a sheet feed tray for supporting the sheet P upright. Reference numeral 10 denotes a discharge tray which is formed of a molding material and is provided on the upper portion of the cartridge cover 2 and serves both to support a document to be fed and to stack discharge sheets.

In this embodiment, an original up to A4 size can be passed through the optical reading system 3.

In the present embodiment, two paper feeders are provided as a plurality of paper feed means. A sheet P is set in a sheet feeding device (ASF) 15 which is one sheet feeding device, and the sheet P is fed to the recording system 4 one by one by a separation roller 14c.

A sheet feeding device (cassette) 30 in which a sheet P, which is the other sheet feeding device, is set is provided at a lower portion of the device.
Are sent to the recording system 4 one by one.

The optical reading system 3 includes a friction roller 3c for pressing a document placed on a document placing table 2a provided integrally with the cartridge cover 2 by a separation roller 3c pressed against a preliminary pressure contact arm 3a.
b, and separated and fed one by one by the friction piece 3b and the separation roller 3c.

Further, the conveying roller 3d pressed by a pressing spring (not shown) and the conveying roller 3 pressed against the conveying roller 3d.
e, the original is conveyed to the contact type image sensor 7 which is an image reading unit. The conveyed document is pressed by the contact-type image sensor 7 by the document pressing plate 6, and the image information is read by the contact-type image sensor 7 while being brought into close contact therewith.

Thereafter, the original is discharged out of the apparatus by a discharge roller 3f pressed by a pressing spring and a discharge roller 3g pressed against the discharge roller 3f.

If a document jam occurs during the reading operation, the document staying inside can be taken out by opening the upper guide 24 and the operation panel 5 which is screwed.

The document table 2a is provided with a slider 2c slidable in a direction (width direction of the document) perpendicular to the document conveyance direction, and is mounted on the document table 2a by the slider 2c. Both sides of the document can be regulated and aligned.

A microswitch (not shown) for detecting whether the distance between the two sliders 2c is 148 mm or less, 182 mm or less, or more is attached to the back surface of the document table 2a. Recognition is possible by detecting at.

The recording system 4 emits a modulation signal from a laser beam oscillator (not shown) of the laser scanner unit 11 based on an image signal output from a control unit (not shown), and outputs this modulation beam to the polygon mirror 11a and the folding mirror 11b. Image forming unit 12 as an image forming unit
Is irradiated on the surface of the photosensitive drum 12b.

The photosensitive drum 12b is a primary charging roller 12
The surface is uniformly charged by d. A latent image is formed on the surface of the photosensitive drum 12b by irradiating the surface of the photosensitive drum 12b with scanning light and irradiating a modulated beam. Further, toner is supplied to the latent image from the toner tank 12f by the developing roller 12e, and the image is visualized on the surface of the photosensitive drum 12b.

The photosensitive drum 12b is provided with the primary charging roller 1
2d, a developing roller 12e, a toner tank 12f, and a cleaning blade (not shown).
a and is configured to be detachable from the apparatus main body 1. The recording cartridge 12a
The cartridge can be replaced by opening the cartridge cover 2.

A transfer roller 12c serving as a transfer charger is disposed at a position of the image forming unit 12 facing the photosensitive drum 12b. Further, the heat fixing device 17, the discharge roller pair 18,
The guide portion 20 and the discharge roller pair 13 are sequentially arranged.

The heat fixing device 17 includes a heater 17 as a heating element.
a, and a pressure roller 17b pressed by a heater 17a
And a film 17d rotating along the outer periphery of the cylindrical guide
And

The photosensitive drum 12 is transferred by the transfer roller 12c.
The sheet P to which the toner image formed on the surface b is transferred is
The toner image is conveyed to the heat fixing device 17 and the toner image is fixed by the heat fixing device 17. After fixing, the sheet is discharged from the discharge port 23 by the discharge roller pair 13 through the discharge roller pair 18 and the guide unit 20. The sheets discharged from the discharge port 23 are stacked on the sheet discharge table 2b and the discharge tray 10 with the recording image surface facing down (face down).

On the downstream side of the discharge roller pair 18, a flapper 19 for switching the discharge direction of the sheet P is provided. By switching the flapper 19 in the lower discharge direction, the sheet P can be discharged straight with the image surface up (face-up) by the discharge roller pair 18.

The paper feeder (ASF) 15 has approximately 100
This is a sheet feeding device for automatically feeding sheets on which sheets are set, and is arranged at the rear of the apparatus main body 1. In the sheet feeding device (ASF) 15, the side edge of the sheet P is regulated by a side regulating plate 15c movably mounted in accordance with the size of the sheet P so that skew does not occur.

When the sheet P accommodated in the sheet feeding device (ASF) 15 receives the sheet feeding signal, the intermediate plate 15b rotates around the fulcrum by a pressing member (not shown) in a direction for pushing the sheet toward the front side. The sheet P in front of the sheet P is pressed against the separation roller 14c.

Then, the separation roller 14c is driven,
The sheets P are separated one by one by a friction piece separating action by the separation roller 14c and the separation pad 14a. The separated sheet P is transported by the transport roller 16a and the transport roller 16a.
The roller 16c is conveyed to the image forming unit 12 by the roller 16c pressed against the roller a. On the other hand, the sheet feeding device (cassette) 30 has a larger sheet storage capacity than the sheet feeding device (ASF) 15 and
This is a paper feeder for automatically feeding up to 50 sheets that can be set, and is arranged at the bottom of the apparatus main body 1.

When the sheet P accommodated in the sheet feeding device (cassette) 30 receives the sheet feeding signal, the intermediate plate 30a is rotated by a member (not shown) about the fulcrum 30b. Accordingly, the sheet P moves upward, and the top sheet P of the sheet P is pressed against the cassette separation roller 32.

Then, the cassette separation roller 32 is driven, and the sheets P are separated one by one by the friction piece separating action of the cassette separation roller 32 and the separation pad 31. The separated sheet P is transported to the image forming unit 12 by the transport roller 16a and the roller 16c that is pressed against the transport roller 16a.

The leading end of the sheet P being transported is detected by a registration sensor (not shown) provided downstream of the transport roller 16a.

On the other hand, in the recording system 4, the image output timing is adjusted so that the leading end of the toner image formed on the photosensitive drum 12b coincides with the leading end of the sheet P, and the transfer roller 12c and the photosensitive drum 12b are The image is transferred to a correct position on the surface of the sheet P conveyed to the nip portion.
The image is recorded on the front side of the sheet P stacked on the sheet feeding device (ASF) 15 or on the lower side of the sheet P stacked on the sheet feeding device (cassette) 30.

A cartridge cover 2 is provided on the apparatus main body 1 so as to be openable and closable. When the cartridge cover 2 is opened, the recording cartridge 12a can be pulled out of the apparatus main body 1 and replaced.

The apparatus main body 1 is provided with an interlock switch (not shown).
The recording system 4 is not operated when the cartridge cover 2 is opened.

The laser scanner unit 11 includes:
A laser shutter (not shown) that opens and closes in conjunction with opening and closing of the cartridge cover 2 is provided to prevent laser light from entering the operator's eyes when the cartridge cover 2 is opened.

When a sheet jam occurs during recording, the sheet P staying inside can be taken out by opening the cartridge cover 2.

Next, a control system of the facsimile machine will be described with reference to a block diagram shown in FIG. FIG.
, A control unit 21 of the facsimile apparatus, a power supply unit 21b for supplying power to the entire apparatus, a modem board unit, an NCU board unit 21e for connecting a telephone, a display for displaying the contents input from the operation unit 21c, and the like And a printer interface 21f1 for obtaining data from the peripheral computer.

The control unit 21 is a CP for controlling the entire apparatus.
U21a1, a ROM 21a2 storing various programs and various data, a RAM 21a3 used as a work area of the CPU 21a1 and temporarily storing various data such as the number of recordings, and an input / output for separating a facsimile from a printer Switching interface 2
1a7.

The control unit 21 is provided with a line memory 21a4 for storing an image of each line of image data. The line memory 21a4 stores one line of image data from the document reading system 3 in the case of transmitting or copying a document, and stores the decoded data of one line in the case of receiving image data. .

Then, the image data stored in the line memory 21a4 passes through the CPU 21a1, adds a recording system control code, and is output from the input / output switching interface 21a7 to the CPU B1 of the recording system 4, and the CPU B1 transmits the recording system control code. The image formation is performed by decoding.

Further, the control section 21 is provided with an encoding / decoding section 21a5 for encoding image information to be transmitted by MH encoding or the like, or for decoding received coded image data and converting it into image data. Have been. Further, a buffer memory 21a6 for storing encoded image data transmitted and received from the encoding / decoding unit 21a5 is also provided.

Next, the recording operation of an image received by facsimile will be described in detail. In this embodiment, 250 sheets of A4 size sheets are set in advance in a sheet feeding device (cassette) 30 arranged at the lowermost portion of the apparatus main body 1 as a main sheet feeding device. Sheets are fed from a sheet feeding device (cassette) 30.

Further, an A4 size sheet which is the same size as the sheet set in the sheet feeding device (cassette) 30 is stored in a sheet feeding device (ASF) 15 arranged at the rear portion of the apparatus main body 1. .

The sheet feeding device (ASF) 15 controls the separation roller 1
4c is driven, the separation roller 14c and the separation pad 14a
The sheet P is separated one by one by the friction piece separating action of the conveying roller 16a and the conveying roller 16a.
The distance to the nip portion between the roller 16c and the roller 16c is 13 mm.

On the other hand, a sheet feeding device (cassette) 30
Then, the cassette separation roller 32 is driven, and the sheet P is separated one by one by the friction piece separating action of the cassette separation roller 32 and the separation pad 31, and then the conveyance roller 16a and the roller 16c pressed against the conveyance roller 16a are separated. The distance up to the nip portion has a large difference of 130 mm.

In the present embodiment, since the conveying speed of the sheet in the sheet feeding section is 36 mm / S, the sheet feeding device (AS
F) When the paper is fed from the paper feeding device (cassette) 30 as compared with the case where the paper is fed from 15, it takes about 3.3 seconds more time to reach the nip between the transport roller 16a and the roller 16c. .

Therefore, in the present embodiment, the first recording sheet P has a distance of 13 mm to the nip between the transport roller 16a and the roller 16c, and has the shortest feeding distance (ASF). ) 15 is controlled to feed paper.

In the facsimile apparatus of the present embodiment, an image is temporarily stored in a memory and recording is started when image information for one page (one sheet) is prepared, instead of performing recording while receiving. It is in sequence.

In a situation where a plurality of pieces of image information are stored in the memory, when a recording operation command is given from the CPU, the first recording sheet P is moved to the image forming section 12.
The paper is fed from a paper feeding device (ASF) 15 having a short paper feeding distance up to and the first sheet of the received image is formed, transferred, fixed, and then discharged.

Accordingly, it is possible to reduce the time required from the feeding of the first sheet of the continuous feeding to the discharge of the first sheet.

The feeding timing when the recording sheet P is fed from the second or subsequent sheet feeding device (cassette) 30 is controlled as follows.

Since the size of the sheet is set to A4 size in advance, the length of the sheet P in the conveying direction is 297 mm.
It is. In the present embodiment, the distance between the preceding sheet and the next sheet during conveyance is set to 20 mm.

Further, the sheets are separated one by one by a cassette separation roller 32 and a separation pad 31 by a sheet feeding device (cassette) 30, and then the leading edge of the sheet is detected by a registration sensor provided downstream of the conveyance roller 16a. Is detected in advance as 140 mm by an experiment.

Therefore, 177 mm (= 29 mm) after the leading edge of the preceding sheet is detected by the above-described registration sensor.
At the time point when (7 mm + 20 mm−140 mm) has elapsed, the feeding of the next sheet P from the sheet feeding device (cassette) 30 is started.

In this way, even when the second and subsequent sheets P of the continuous paper feeding are fed from the paper feeding device (cassette) 30 having a long feeding distance, no extra time is required for the recording operation.
Regardless of the sheet feeding device from which sheet is fed, an optimum sheet feeding timing can be achieved while maintaining a predetermined interval between the sheets of the preceding sheet and the next sheet.

The paper feeding device (ASF) 1 for continuous paper feeding
It is also possible to control not only one sheet feeding but also a plurality of sheets feeding from 5, and to feed the subsequent sheets by the sheet feeding device (cassette) 30.

In the above-described embodiment, the recording section in the facsimile apparatus has been described.
The same operation can be obtained by performing the same control not only in the facsimile apparatus but also in an image forming apparatus such as a copying machine or a printer.

Further, as for the image formation on the sheet, not only the above-mentioned electrophotographic method but also a known technique such as an ink jet recording method can be applied.

[0083]

As described above, when feeding the first sheet in continuous feeding or when feeding only one sheet alone, a plurality of sheet feeding means containing sheets of the same size are used. Since the sheet is fed by the sheet feeding unit having a short sheet feeding distance to the inner image forming unit, the time required from sheet feeding to sheet discharging can be reduced.

For the first sheet feeding, the time required from sheet feeding to sheet discharging is shortened, and for the second sheet and thereafter, sheet feeding means having a large sheet storage capacity supplies the sheet. It is possible to minimize the possibility of running out of sheets even in a recording operation in which a large number of images are continuously formed, while optimizing the time required for recording by performing paper.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a facsimile apparatus according to the present embodiment.

FIG. 2 is an explanatory cross-sectional view showing the entire configuration of the facsimile apparatus according to the present embodiment.

FIG. 3 is a block diagram illustrating control of the facsimile apparatus according to the embodiment.

FIG. 4 is an explanatory cross-sectional view showing the overall configuration of a conventional facsimile machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Apparatus main body, 2 Cartridge cover 2a Original mounting table 2b, 102b Sheet discharge table 2c Slider, 3,103 Optical reading system 3a Pre-pressing arm 3b Friction piece 3c Separation roller 3d Transport roller 3e Transport roller 3f Discharge roller 3g Discharge roller 4, 104 Recording system 5, 105 Operation panel 6 Original press plate 7 Contact image sensor 8, 108 Feed tray 10 Eject tray 11 Laser scanner unit 11a Polygon mirror 11b Folding mirror 12 Image forming unit 12a Recording cartridge 12b Photoconductor drum 12c Transfer roller 12d Primary charging roller 12e Developing roller 12f Toner tank 13, 18 Discharge roller pair 14a Separation pad 14c Separation roller 15 Paper feeder (ASF) 15b Middle plate 15c, l15c Side regulating plate 16a Transport Roller 16c Roller 17 Thermal fixing device 17a Heater 17b Pressure roller 17d Film 18 Discharge roller pair 19 Flapper 20 Guide unit 21 Control unit 23 Discharge port 24 Abber guide 30 Paper feeder (cassette) 30a Middle plate 31 Separation pad 32 Cassette Separation roller

Claims (5)

[Claims] 1. A plurality of paper feeding means capable of storing sheets of the same size, which separates and feeds the stored sheets one by one, and forms an image on the sheets fed from the plurality of paper feeding means. An image forming apparatus comprising: a plurality of sheet feeding units, wherein sheets of the same size are stored in the plurality of sheet feeding units; An image forming apparatus, wherein a sheet is fed by a sheet feeding unit having a shortest sheet feeding distance to the image forming unit. 2. When continuously feeding sheets of the same size,
2. The image forming apparatus according to claim 1, wherein at least a first sheet is fed by a feeding unit having a shortest feeding distance to the image forming unit. 3. 3. The image forming apparatus according to claim 2, wherein a sheet feeding means different from the sheet feeding means for feeding at least the first sheet feeds the subsequent sheets. 4. A sheet feeding means for feeding at least a first sheet has a small sheet storage capacity, and a sheet feeding means for feeding subsequent sheets has a large sheet storage capacity. Item 4. The image forming apparatus according to Item 3. 5. The image forming apparatus according to claim 1, wherein the image forming apparatus is a facsimile machine.