JPS61277505A - Image former - Google Patents

Abstract

PURPOSE:To get rid of the collation of paper by manual operation as well as to detect a paper jam without fail, by installing a device in which the paper discharged to the out-side of a machine body is automatically housed in the paper discharge tray installed in an upper part of the machine body, in a position outside the machine body, and attaching a sensor to a discharge port in addition. CONSTITUTION:Inside a box body 24a of a detachable paper discharge unit 24, there are each three of driving rollers 26, 27 and 28 and driven rollers 26a, 27a and 28a, and also there are provided with guide plates 29, 30 and 31 for paper X. In and around an opening part 11a of a machine body 11 and a discharge part 24a of a paper discharge unit 24, both first and second sensors S1 and S2 detecting a pass of the paper X each are installed. Therefore, the paper X discharge out of a fixing device 14 passes through between the guide plate 29 and a 3-piece set of rollers 26, 27 and 28 and housed in a paper discharge tray 25, but inside and outside of the paper X are turned over in this process and it is piled up in turning its printing surface downside, while the sensor S2 operates, detecting a paper jam in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus such as an LED printer, a laser printer, or a copying machine.

[Conventional technology]

Conventionally, in image forming devices such as LED printers, laser printers, and copiers, paper is fed from a paper cassette, printed characters and images are transferred by a photoreceptor drum, and then the paper with the characters and images fixed by a fixing device is The structure is such that the paper is ejected from a paper ejection unit provided on the side of the machine to a paper ejection tray.

[Problem that the invention seeks to solve]

However, in the image forming apparatus with the above structure, the paper that is ejected onto the paper ejection tray has the printed side on which characters and images are printed facing upward, so manual work is required to align the pages of the paper after printing is completed. Particularly in a device that continuously prints on a large number of sheets, such as a printer, there is a drawback that manual page alignment requires a lot of time. In addition, in a structure in which a paper ejection section is provided on the side of the machine, a paper ejection tray must be provided adjacent to the paper ejection section, and the paper ejection tray protrudes far from the machine body, resulting in the image forming device being damaged. Not only is it large in size, but it also has the disadvantage of requiring a large installation area.

The present applicant has developed a copying machine equipped with a paper ejecting mechanism that first guides the printed paper that has been transferred and fixed onto the upper part of the machine, and stores the paper with an inverted trace on the original holding plate on the upper part of the machine. [Patent Application No. 58-36747 (Japanese Unexamined Patent Publication No. 59-176758), Japanese Patent Application No. 58-367]
No. 48 (Japanese Unexamined Patent Publication No. 59-176759)]. These copying machines can solve the above problems, but when there is no need for page alignment or when there is sufficient installation space for the image forming device, the image forming device with the built-in paper ejection mechanism is expensive. The drawback was that it was a high-cost copying machine.

The present invention has been developed in view of the above-mentioned problems, eliminates the above-mentioned problems, eliminates the need for /J-shaping and page alignment work, and furthermore, when there is sufficient page alignment and installation space, the paper discharge To provide an image forming apparatus having the versatility of being usable with a mechanism removed and having a detection means capable of appropriately detecting a paper jam whether a paper ejection mechanism is installed or removed.

[Means for solving problems]

In order to solve the above problems, the present invention provides an LED printer,
In image forming devices such as laser printers and copiers,
Paper is fed from the paper cassette, transferred and fixed, and then ejected outside the machine through an opening provided on one side of the machine. The paper is guided along the side of the machine to the top of the machine and reversed. A unitized paper ejection mechanism that is stored in a paper ejection tray provided at the top is removably provided on one side of the machine, and the passage of paper is detected at the opening of the machine body and the ejection port of the paper ejection mechanism, respectively. the first sensor and the second sensor are provided, the first sensor is enabled when the paper ejecting mechanism is removed from the machine body, and the second sensor is enabled when the paper discharging mechanism is attached to the machine body. A jam detection means is provided for detecting a paper jam based on signals from the selection means and the first and second sensors.

[Effect]

By configuring the image forming apparatus as described above, when the unitized paper ejection mechanism is attached to the machine body, the paper on which characters, images, etc. are printed are reversed and stacked on the paper ejection tray, which is different from the conventional method. There is no need for manual page alignment, and there is no need to arrange a paper ejection tray on the side of the printer as in the past, so the printer can be made smaller and its installation space can be reduced. In addition, when there is no need for page alignment or when there is sufficient installation space, the unitized paper ejection mechanism can be used without being attached to the machine body, so its versatility is widened, and the selection means described above can be selected. As a result, paper jams can be accurately detected whether the paper ejection mechanism is installed or removed.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing the structure of a laser printer as an embodiment of the present invention. In the figure, reference numeral 11 denotes the body of a laser printer. Inside the body 11, a laser beam scanning device 12, a photosensitive drum 3, and a fixing device 14 are provided. Near the periphery of the photosensitive drum 13, A charger 15, a developing device 16, a transfer device 17, a cleaning device 18, and the like are arranged. A fan F is provided at the rear of the laser beam scanning device 12, and the laser beam scanning device 12
The heat emitted from the fixing device 14 is released to the outside of the machine body 11, and the ozone generated inside the machine body 11 is absorbed by an ozone filter (not shown).

It looks like this.

The charger 15 charges the photosensitive drum 13 with corona discharge.
uniformly charge the entire surface of the Next, by scanning the surface of the photoreceptor drum 13 with a modulated and deflected laser beam from the laser beam scanning device 12, an electrostatic latent image of characters or images for printing is formed. The electrostatic latent image formed on the surface of the photoreceptor drum 13 is visualized with toner by the developing device 16 (in a laser printer, contrary to a copying machine, it is necessary to attach toner to the exposed area, so development is performed using a photosensitive drum). Since toner having the same polarity as the chargeability of the photoreceptor of the body drum 13 is used, the toner is repelled by the charge on the unexposed areas and adheres only to the exposed areas. The toner image formed on the surface of the photoreceptor drum 13 as described above is transferred onto a sheet of paper existing between the photoreceptor drum 13 and the transfer device 17 by a corona discharge of opposite polarity to the toner by the transfer device 17. The toner remaining on the surface of the photoreceptor drum 13 is cleaned by the cleaning device 18 and then charged and charged.
Prepare for exposure and transfer. In the laser printer having the above structure, the paper is fed from the paper feed cassette 19 by the paper feed mechanism 20 and reaches between the photoreceptor drum 13 and the transfer device 17 via the registration roller 21. The toner image is transferred, and the paper further passes through the fixing device 14, whereby the toner image is fixed onto the paper by heating or the like, and printing is completed. In the conventional laser printer, the paper printed as described above passes through the opening 11a provided on the side of the machine body 11 and is ejected outside the machine body 11, but in this embodiment, the paper is ejected from the paper ejection unit 24. The sheet can then be turned over and stored in the sheet discharge tray 25 provided at the top of the body 11.

FIG. 2 is a diagram showing the detailed structure of the paper discharge unit 24 of the laser printer. As shown in the figure, the paper ejection unit 2
4 includes three drive rollers 26, 27.28 and the drive rollers 26, 27.2 along the paper ejection path in the housing 24a.
Followed rollers 26a and 27a rotate in conjunction with the rotation of 8.
, 28a are rotatably arranged, and furthermore, the drive roller 2
In this structure, guide plates 29, 30, and 31 are disposed between 6, 27, and 28, and are arranged to face each other and guide the printed paper. A fitting portion 24b shaped to fit into the side of the body 11 of the laser printer is provided on the side of the paper ejection unit 24.
is formed. Note that the driving rollers 26, 27 .
28 is at least the size of a business card (approximately 9c'
ITl) below. The paper ejection unit 24 is connected to the machine body 11.
To fix it to the side part of the sheet discharging unit 24, insert the locking member 3 into the locking member 32a fixed to the machine body 11 side from the fitting part side of the paper ejection unit 24.
This is done by fitting 2b. Further, when the paper ejection unit 24 is to be removed from the body 11, this is done by pulling out the locking member 32b from the locking member 32a.

The opening 11a of the machine body 11 and the discharge section 2 of the paper discharge unit 24
A first sensor S1 and a second sensor S2, each of which detects the passage of paper X, are provided near 4c. The sensor S1 and the sensor S2 are constituted by, for example, a photocoupler made of a photodiode and a phototransistor.

FIG. 3 is a diagram showing the structure of the drive system of the paper ejection unit 24. As shown in FIG. The drive system of the paper ejection unit 24 is as shown in the figure.
The drive roller 26 corresponds to the drive roller 26, 27, 28.
, 27, 28 drive sprocket 26'
, 27'28' are arranged, and driven rollers 26a, 27a
is pressed against the drive rollers 26, 27, 28 by springs 35, 36, and is rotated following the movement. Although the relationship between the driving roller 28 and the driven roller 28a is also omitted from illustration,
A driving gear 28'' is formed integrally with the driving sprocket 28' on the 6-drive sprocket 28' to which the driven roller 28a of the driving roller 28 is pressed by a coil spring, and the driving force of the driving gear 28°' drives the driven gear 33 is arranged to drive the drive sprocket 26';
27', 28' have the drive sprockets 26', 27'.
'.

The chain 34 that transmits the driving force to the support roller 40
, 41, 42 and suspended. The chain 34 is also suspended on a drive sprocket 39 that provides driving force to the chain 34. The drive sprocket 39 is integrally equipped with a drive gear 39'', which meshes with a gear 38, which in turn meshes with a gear 37. Gears 37 and 38 are gears that are driven by the fixing device 14 provided on the body 11 side. Further, the gear 38 is rotatably supported by a support plate 43 which is rotatably supported by a support shaft 39' of the drive gear 39. The support plate 43 is biased downward by a fill spring 44 and presses the gear 38 against the gear 37. The gear 37 is adapted to rotate in conjunction with the drive mechanism of the fixing device 14, that is, the paper transport mechanism within the body 11. The paper ejection unit 24 configured as described above is attached to the side of the machine body 11 by a locking member 32.
When b is inserted into the locking member 32a and fitted and fixed, the drive sprockets 26' and 27 in the paper ejection unit 24 interlock with the paper transport mechanism in the machine body 11, such as the drive mechanism of the fixing device 14.
", 28', a drive system consisting of a drive gear 39, a chain 34, etc., is also driven via the gears 37 and 38,
Drive roller 26, 27, 28 and driven roller 26a, 2
A paper transport mechanism consisting of 7a and 28a is also driven.

In this state, the printed paper discharged from the fixing device 14 is placed between the guide plates 29 and 29, between the drive roller 26 and the driven roller 26a, between the guide plates 30 and 30, and between the drive roller 27 and the driven roller 27a. The paper passes between the guide plates 31 and 31 and between the drive roller 28 and the driven roller 28a, and is stored in the paper discharge tray 25 through the discharge port 24c provided at the upper part of the paper discharge unit 24. At this time, the paper is transferred to the paper ejection unit 24.
During the transport process, the sheets are reversed and stacked in the discharge tray 25 with the printed side facing down, so that the pages are in order and there is no need to align the pages again.

FIG. 4 is a longitudinal cross-sectional view of a state in which the paper ejection unit 24 is not attached to the side of the body 11. By attaching a paper ejection tray 45 to the opening 11a of the machine body 11 through which printed paper is ejected, and storing the paper ejected from the fixing device 14 in the paper ejection tray 45, it is possible to eliminate the conventional page alignment function. Can be used as a regular laser printer.

FIGS. 5(a) and 5(b) show that the paper ejection unit 24 is
FIG. 3 is a circuit diagram showing a circuit configuration of a detector that detects a jam of paper X when it is attached to the printer and when it is detached from the detector. The same figure (a
) and (b), SK is a socket for attaching and connecting the paper discharge unit 24 to the machine body 11. By attaching the paper ejection unit 24 to the machine body 11, the socket SK is automatically connected, and when the power E is turned on, the selection switch SW is turned on.
When I is turned to the b side, the second sensor S on the paper ejection unit 24 side
2 is valid. In this state, the laser printer starts printing, and when the second sensor S2 detects the paper X within a predetermined time, an output is generated from the terminal T and it is determined that the paper X is not jammed. If the second sensor S2 does not detect the paper X within a predetermined time, no output is generated from the terminal T, and the paper It is determined that it is clogged.

When the paper discharge unit 24 is detached from the body 11, the selection switch SWI is turned to the a side to enable the first sensor S1. When the laser printer starts printing in this state and the first sensor S1 detects the paper X within a predetermined time, an output is generated from the terminal T, indicating that the paper X is not jammed in the paper ejection mechanism inside the machine body 11. On the other hand, if it cannot be detected, it can be determined that there is a blockage.

In addition, in the same figure (b), the paper ejection unit 24 is
When the socket SK is connected and the power supply E is turned on, the power supply E is input to the terminal 1 of the AND circuit AND1 through the socket SK, so the AND circuit ANDI becomes valid; Since the power supply E is inverted and inputted to the terminal 1 of AND2 via the inverter INI, the AND circuit AND2 becomes invalid. In this state, the laser printer starts printing, and when the second sensor S2 detects paper X within a predetermined time, the detection signal is input to terminal 2 of the AND circuit AND1, and the signal is sent from the AND circuit AND1 via the OR circuit ORI. No output is generated and it is determined that paper X is not jammed. On the other hand, if paper X cannot be detected within a predetermined time, it is determined that paper X is jammed. Place the paper ejection unit 24 on the machine 1.
1, the AND circuit AND2 becomes valid and the AND circuit AND1 becomes invalid, so when the first sensor S1 detects the paper X within the predetermined range, it is determined that the paper X is not jammed; If paper X is not detected within the time, it is determined that paper X is jammed.

Although the above embodiments have been described using a laser printer as an example, the present invention is not limited to laser printers, and can be widely used in image forming apparatuses such as LED printers and copying machines.

Further, in a copying machine or the like, a paper ejection tray for storing ejected paper may be provided above a so-called document holding plate provided at the upper part of the machine body 11.

Furthermore, if the paper ejection unit 24 is sold as an accessory component separate from the machine body 11, the user can purchase only the image forming apparatus main body or both the image forming apparatus main body and the paper ejection unit depending on the purpose of use. It is also possible to do so.

〔Effect of the invention〕

As described above, according to the present invention, there is no need to dispose a paper ejection tray on the side of the printer as in the conventional printer, so that the printer can be made smaller and its installation space can be reduced. In addition, first and second sensors are provided at the opening of the machine body and the discharge port of the paper discharge mechanism to detect the passage of paper, respectively, and when the paper discharge mechanism is removed from the machine body, the first sensor is enabled and the paper discharge When the paper mechanism is attached to the machine body, a selection means for enabling the second sensor and a jam detection means for detecting a paper jam based on signals from the first and second sensors are provided. This selection provides an excellent effect in that paper jams can be accurately detected whether the paper ejection mechanism is attached or detached.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing the structure of a laser printer according to the present invention, and FIG. 2 is a longitudinal cross-sectional view of its paper ejection unit. Fig. 3 is a diagram showing the drive system of the paper ejection unit, Fig. 4 is a longitudinal sectional view showing the state in which the paper ejection unit is not attached to the machine, and Fig. 5 is a diagram showing the drive system of the paper ejection unit.
Figures (a) and (b) are diagrams each showing a circuit configuration of a paper jam detector. In the figure, 11... body, 12... laser beam scanning device, 13... photosensitive drum, 14... fixing device, 15... charger, 16... Developing device, 17
...Transfer device, 18...Cleaning device, 19
...Paper feed cassette, 20...Paper feed mechanism, 21.
...Registration roller, 22...Reflector, 23...
... Lens, 24 ... Paper ejection unit, 25 ...
Output tray, 26°27.28... Drive roller, 2
6a, 27a, 28a...driven roller, 26°, 2
7', 28'. 39... Drive sprocket, 29, 30. 31...
... Guide plate, 32 ... Locking member, 33 ... Followed gear, 35, 36. 44 ... Coil spring, 37, 3
8... Gear, 28", 39"... Drive gear,
40.41.42...Support roller, 43...Support plate, Sl, S2...Sensor, SWl...Selection switch, SK...Socket.

Claims (1)

[Claims] Paper is fed from the paper cassette, transferred and fixed, and then ejected from the machine through an opening provided on one side of the machine. The paper is guided along the side of the machine to the top of the machine and placed in the paper output tray. A unitized paper ejection mechanism for storing the paper is removably provided on one side of the machine body, and first and second paper ejection mechanisms detect passage of paper at an opening of the machine body and an ejection port of the paper ejection mechanism, respectively.
a selection means for activating the first sensor when the paper ejection mechanism is attached to or removed from the machine body and enabling the second sensor when the paper ejection mechanism is attached to the machine body; and a jam detection means for detecting a paper jam based on a signal from a second sensor.