JPH02182636A - Image forming device - Google Patents

Abstract

PURPOSE:To keep on mass capacity image forming by making the change-over of feed cassettes by a change-over means in accordance with priority by a designating means when it is detected by a detecting means that no transfer form is available in the feed cassettes which are being selected by the detecting means. CONSTITUTION:When the priority of feed cassettes is designated by the input by keys or the input by commands, and when it is thereafter judged that the form is consistent with a required one in size, a control section 61, accompanied with image forming operations, takes a form out of each feed cassette in order as designated here in above so as to send it to an image transfer section. Name ly, the control section 61 controls a feed motor to let a feed roller take the form out of the first feed cassette. In the operation, when it is detected by a form availability detector that no form is available, the control section 61 controls a feed motor for the next feed cassette based on the timing of the detection so that the form is taken out of said feed cassette. Similar operations should be processed thereafter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an image forming apparatus used as, for example, a laser printer or an electronic copying machine.

(Prior Art) In recent years, various image forming apparatuses have been developed, such as a laser printer that forms an image (printing operation) using an electrophotographic method. In this type of image forming apparatus, if the paper (transfer material) in the paper cassette becomes empty during continuous image forming operation, the image forming operation is interrupted at that point. There is. In such a case, even if the image forming apparatus main body is equipped with multiple paper cassettes and each cassette contains paper of the same size, the operator may not be able to instruct the operator to switch the paper cassette. The interrupted image forming operation will not be restarted unless the operator replenishes paper. In this way, if the paper runs out midway, it is impossible to perform continuous image forming operations.

Similarly, even if an image forming apparatus is equipped with a paper cassette as an optional device in addition to the paper cassette provided in the main body of the image forming apparatus, if the state runs out of paper midway through, even if the main body of the image forming apparatus is Even if the same size paper is stored in the paper cassette and the optional paper cassette, continuous image formation cannot be performed by automatically switching between the paper cassette in the main unit and the optional paper cassette. Ta.

(Problems to be Solved by the Invention) As described above, in conventional devices, even if paper of the same size is stored in another paper cassette, the selected paper cassette is When the paper runs out, the image forming operation is interrupted at that point, and there is a drawback that continuous image forming operation cannot be performed.

Therefore, the present invention makes it possible to continue the image forming operation even if a certain paper cassette runs out of paper in the middle of continuous image forming operations, and to continuously perform large-capacity image forming. The purpose of the present invention is to provide an image forming apparatus that enables the following.

[Structure of the Invention] (Means for Solving the Problems) The image forming apparatus of the present invention includes a plurality of paper feed cassettes, and forms an image on a transfer material supplied from these paper feed cassettes. a designation means for specifying the priority order of paper feeding in the paper feed cassette; a detection means for detecting the presence or absence of a transfer material in the paper feed cassette; and a switching means for switching the paper feed cassette according to the priority order determined by the designation means when no transfer material is detected.

(Function) The present invention uses the above-described means to automatically feed paper continuously from different paper feed cassettes in response to detection of the absence of a transfer material.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIGS. 2 and 3 show the external appearance and internal configuration of, for example, an electrophotographic laser printer as an example of an image forming apparatus according to the present invention. In other words, this laser printer is electrically connected to a host device such as a personal computer via an interface cable, and performs image formation (printing operation) according to image information sent from the host device. It also serves as the printer body 1 and a mounting stand for this printer body 1.
It is comprised of a paper feed cassette device 2 as an optional device that supplies paper P to the printer main body 1.

The printer main body 1 has the following configuration.

That is, 4 is a casing, and the rear part of the top surface of this casing 4 is raised one step higher, and a recessed part 5 as a paper discharge part is formed in the center of the top surface. The fourth part 5 is provided with a jogger device 7 having a pedestal (jogger tray) 6. An operating section (specifying means) 8 is provided on the right side of the fourth section 5, and a paper discharge tray 9 is mounted on the front side of the housing 4.

On the other hand, an image forming mechanism is provided inside the housing 4. That is, 10 is a drum-shaped photoreceptor, around which a charging device 11 and a laser optical system 1 are arranged along the rotation direction.
2, developing device 13, transfer charger 14, peeling charger 1
5, a cleaning device 16, and a static eliminator 17 are arranged in this order.

The laser optical system 12 includes a semiconductor laser oscillator (not shown) such as a laser diode that generates a laser beam modulated according to dot image data, and a collimator lens that collimates the laser beam output from the laser oscillator. (not shown), a rotating mirror (polygon mirror) 1 that scans the output light from this collimator lens
8. An fθ lens 19 that allows the laser beam scanned by the rotating mirror 18 to pass through, reflecting mirrors 20 and 21 that reflect the laser beam that has passed through the fθ lens 19 toward the photoreceptor 10, and this reflecting mirror 20. It is composed of a correction lens 22 that guides the laser beam reflected by the photoreceptor 21 to the surface of the photoreceptor 10, and the like.

Further, a conveyance path 24 is formed in the housing 4 and extends forward through an image transfer section 23 between the photoreceptor 10 and the transfer charger 14, and a paper feeding path 24 is formed in the housing 4. Cassette (hereinafter sometimes referred to as the first paper feed cassette) 25
Paper P automatically fed from the paper feed roller 26 and aligning roller pair 27 from the paper feed cassette device 2
Paper P1 or manual feed tray 28 that is automatically fed from
The sheet P manually fed from the image transfer section 23 is guided from the image transfer section 23 to the image transfer section 23 .

A pair of aligning rollers 29 is arranged on the upstream side of the image transfer section 23 of the conveyance path 24, and a pair of heat rollers 30 as a fixing device is arranged on the downstream side. A paper discharge selector 31 and a pair of paper discharge rollers 32 are arranged. Further, at the end of the conveyance path 24, a branch conveyance path 34 is formed which includes a pair of paper discharge rollers 33 for guiding the sheets P sorted by the paper discharge selector 31 to the four sections 5.

The paper feed cassette device 2 includes, for example, two paper feed cassettes (
Hereafter, the second. (Sometimes called the third paper feed cassette) 35
．． It is equipped with 36. And these paper feed cassettes 35
．． The paper P in 36 is fed to paper feed rollers 37 and 38, respectively.
The sheets are taken out one by one. The paper P taken out by the paper feed roller 37 is conveyed by the aligning roller pair 39, and the paper P taken out by the paper feed roller 38 is conveyed through the guide path 41 by the aligning roller pair 39, 40, and is transported inside the printer main body 1. Guided by a pair of guide rollers 42,
By this pair of guide rollers 42, the pair of aligning rollers 2
It is designed to lead you to 9.

In such a configuration, in a printing operation, the photoconductor 10 is first rotated and the charging device 11 is operated to uniformly charge the surface of the photoconductor 10, and then the laser optical system 12 charges the photoconductor 10. Exposure corresponding to the dot image data is performed on 10 to form an electrostatic latent image. The electrostatic latent image on the photoreceptor 10 is developed by a developing device 13 that uses a two-component developer consisting of toner and carrier, and is sent to an image transfer section 23 as a toner image.

Meanwhile, in synchronization with the toner image forming operation, the paper feed cassette 2
5, 35. The paper P1 selectively taken out from 36 or the paper P fed manually is transferred to the aligning roller pair 2.
The toner image fed through the photoreceptor 9 and formed on the photoreceptor 10 as described above is transferred to the paper P by the action of the transfer charger 14.
transferred on top.

The paper P on which the toner image has been transferred is peeled off from the surface of the photoreceptor 10 by the action of the peeling charger 15, passes through the conveyance path 24, and is sent to the heat roller pair 30, where the toner image is removed. is melted to a constant volume. Paper P after fixing
The paper ejection direction is sorted by the paper ejection selector 31,
The paper is discharged onto the pedestal 6 of the upper jogger device 7 or onto the lower paper discharge tray 9.

Further, after the toner image is transferred onto the paper P, the remaining toner on the photoreceptor 10 is cleaned by the cleaning device 16, and the next printing operation is ready.

In addition, 1. 2.93 Paper cassette 25°35.36
is a universal type that can store paper P of various sizes.

Further, the operation section 8 is provided with a designation key (not shown) for designating the priority order of paper feeding according to the size of each paper P, and each paper feeding cassette is set in accordance with the designation of this key. Continuous paper feeding from 25, 35, and 36 is possible. In other words, when the paper feed from the three paper feed cassettes 25, 35, and 36 is prioritized using the specified key, the cassettes are switched according to that order, and the next cassette is switched depending on whether the priority cassette is out of paper. automatic paper feeding starts. As a result, even if you run out of paper during continuous image formation,
By continuously feeding paper from another cassette, it is possible to continue the image forming operation.

FIG. 4 shows an electric circuit of a laser printer configured as described above. That is, in the printer main body 1, 61 is a control unit in charge of overall control, and the CPU
(central processing unit), etc., to which the operation section 8 is connected, and an external host device (for example, a personal computer, a word processor, etc.) 63 via an ink face cable 62. is connected.

The control unit 61 includes a paper size detector 64 that is provided for the paper feed cassette 25 and detects the size of the stored paper, a paper presence/absence detector 66 that detects the presence or absence of paper, and a paper feed roller 26. a paper feed motor 67 that drives the heater 68 of the heat roller pair 30, and a transfer charger 14.
A high-voltage power source 69 for transfer, which drives the .

Although not shown in the drawing, the control section 61 receives signals from various sensors and other devices, and also drives the photoreceptor 10, the developing device 13, the heat roller pair 30, the conveyance path 24, etc. at least one motor that
It also controls electromagnetic clutches and solenoids that control various transmission mechanisms, high-voltage power supplies that drive various chargers other than the transfer charger, laser oscillators, rotating mirrors, etc., as well as signals from the paper size detector 64, etc. The image formation magnification (image formation conditions) can be changed according to the image formation conditions.

Further, in the paper feed cassette device 2, 71 is a control unit that controls the overall control, and is mainly composed of a CPU and the like. This control unit 71 includes paper size detectors 72, 73, which are provided for each paper feed cassette 35, 36, and which detect the size of the stored paper, and paper presence/absence detectors 76, 73, which detect the presence or absence of paper. 77, paper feed roller 37.38
Paper feed motors 78 and 79 that drive the paper feed motors 78 and 79 are connected.

Next, the continuous paper feeding operation in the above configuration will be explained with reference to the flowchart shown in FIG.

Now, when the power of the laser printer is turned on, the control unit 61
performs the initial operation of the printer body 1,
For example, energization to the heater 68 is started, and the heat roller pair 30 is warmed up.

When the initial operation is completed in this way, the control section 61 receives various signals from the first to third paper feed cassettes 25, 35, 36, paper size detectors 64, 72, 73, and paper presence/absence detectors 66, 76. Check each output of .77. When this check is completed, the control unit 6
1 uses, for example, a display (not shown) of the operation unit 8 to guide the operator (user) to specify the priority order of paper feeding in the paper feeding cassette. This makes it possible to manually input a key or command from the operation unit 8 or the host device 63 to specify the priority order of the paper.

Now, in the above state, when there is a key input from the operation section 8 or a command input from the host device 63, the control section 61 stores the priority order in the internal memory, and also stores the priority order for each paper feed cassette. Compare the paper sizes in 36.

Here ζ By manual input or command input of the above keys,
For example, the first. Second. Third paper cassette 25-35-3
Assume that a priority order of 6 is specified (the priority order is arbitrary). Then, when it is determined that the paper sizes match by comparing the paper sizes of each cassette 25, 35, and 36, the control unit 61 transfers the paper P from each cassette in the specified order according to the above-described image forming operation. is taken out and supplied to the image transfer section 23. That is, the control unit 61
First, the paper feed motor 67 is controlled to cause the paper feed roller 26 to take out the paper P from the paper feed cassette 25. In this paper feeding operation from the paper feeding cassette 25, when the paper presence/absence detector 66 detects that there is no paper (vapor empty state), the control section 61 controls the feeding operation via the 1iQ control section 71 based on the detection timing. By controlling the paper motor 78, the paper P is taken out from the paper feed cassette 35 by the paper feed roller 37. Furthermore, this paper feed cassette 3
5, when the paper presence/absence detector 76 detects that there is no paper, the controller 61 controls the paper feed motor 79 via the controller 71 based on the detection timing.
By controlling this, the paper P is taken out from the paper feed cassette 36 by the paper feed roller 38. In the paper feeding operation from the paper feeding cassette 36, the control unit 61 takes out the paper P from the paper feeding cassette 36 until the paper presence/absence detector 77 detects that no paper is present.

Note that when the paper presence/absence detector 77 detects that there is no paper, this is notified to the operator via the operation unit 8, and the image forming operation is stopped. Thereby, at the maximum, the image forming operation can be continued continuously until all the sheets set in the laser printer are used up.

Further, if it is determined that the paper sizes of the upper cassette and the lower cassette with the highest priority do not match by comparing the paper sizes of each cassette 25, 35, 36, the control unit 61
changes the image forming magnification in the image forming operation described above according to image information and paper size. From then on, each cassette 25, 35, 36
Paper feeding operation from the next (lower) cassette is performed continuously at the timing of paper out detection by each of the paper presence/absence detectors 66, 76, and 77.

This allows continuous operation by automatically changing the magnification even if the paper sizes of the cassettes are different.

Note that if, for example, only one of the three paper feed cassettes 25, 35, 36 is specified by key input from the operation section 8 or command input from the host device 63, the paper stored in that cassette is Paper P
Image formation is not performed on more than the allowable number of sheets. That is, when the paper presence/absence detector of the corresponding paper feed cassette detects that there is no paper, a paper empty message is called to the operator and the image forming operation is stopped.

As mentioned above, by specifying the order of paper feeding from each paper cassette and automatically switching the paper cassette when there is no more paper to feed, it is possible to continuously feed paper from different paper cassettes. This allows paper feeding operations to be performed.

In other words, even if, for example, the printer's paper cassette runs out of paper midway through, it will automatically feed paper continuously to the paper cassette provided in the paper cassette device at the timing of paper out detection. It becomes possible to move the As a result, the continuous image forming operation will not be interrupted midway due to interruption of the paper feeding operation due to no paper, until all the set sheets are used up at the maximum. Therefore, large-capacity image formation can be performed continuously.

In the above embodiment, when the paper sizes of the cassettes are different, the image forming operation is continued after securing an image forming area suitable for the paper size by changing the magnification, but the present invention is not limited to this. , for example, by correcting the image forming area.

In addition, although the description has been given using a laser printer in which the printer body is equipped with a paper feed cassette device, it can also be applied to a printer that is configured only with a printer body equipped with multiple paper feed cassettes, and furthermore, It is not limited to the number of.

It goes without saying that other modifications may be made without departing from the gist of the invention.

[Effects of the Invention] As described in detail above, according to the present invention, even if a certain paper feed cassette becomes out of paper in the middle of a continuous image forming operation, the image forming operation can be continued. An image forming apparatus capable of continuously forming large-capacity images can be provided.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a flowchart for explaining the continuous paper feeding operation of the present invention, and FIG. 2 is an external appearance schematically showing the configuration of a laser printer according to the present invention. 3 is a side sectional view schematically showing the internal structure of the laser printer, and FIG. 4 is a block diagram schematically showing the electric circuit of the laser printer. DESCRIPTION OF SYMBOLS 1...Printer main body (apparatus main body), 2...Paper feed cassette device, 8...Operation unit (specifying means), 25...(
1st) paper feed cassette, 35...(2nd) paper feed cassette, 36...(3rd) paper feed cassette, 26, 37° 38
... Paper feed roller, 61.71 ... Control unit (switching means), 63 ... External host device (designation means), 64°72.73 ... Paper size detector, 66.76°77
...Paper presence/absence detector (detection means), 67.78°7
9...Paper feed motor.

Claims (2)

[Claims] (1) In an image forming apparatus that is provided with a plurality of paper feed cassettes and forms an image on a transfer material supplied from these paper feed cassettes, a designating means for specifying the priority order of paper feeding of the paper feed cassettes; a detection means for detecting the presence or absence of a transfer material in the paper feed cassette; and when the detection means detects that there is no transfer material in the selected paper feed cassette, feeding paper according to the priority order determined by the designation means; An image forming apparatus comprising: switching means for switching cassettes. (2) In an image forming apparatus that forms an image on a transfer material supplied from a paper feed cassette provided in the apparatus main body or a paper feed cassette provided separately from the apparatus main body, the paper feed cassette of the apparatus main body and a specifying means for specifying the priority order of paper feeding for a separately provided paper feeding cassette; a detecting means for detecting the presence or absence of a transfer material in the paper feeding cassette; An image forming apparatus comprising: switching means for switching paper feed cassettes according to the priority order determined by the specifying means when no transfer material is detected.