JPH04368877A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To provide an image forming apparatus detecting the width of recording paper. CONSTITUTION:The recording paper in the paper supply cassette 340 of a digital copier is fed by the paper supply roller 330 driven by a paper feed motor 312 and a paper supply sensor 306 and paper width sensors 307, 308, 309 are arranged on the feed route up to a position A. A carriage motor 311 moves an injection head cartridge 319 on a platen 217. A CPU (not shown in a drawing) detects the width of the recording paper on the detection result of the presence of the passed recording paper detected by the paper width sensors 307, 308, 309. A manual insertion sensor 31 has function for detecting the feed of the manually inserted paper from a B-direction and the CPU also detects the width of the manually inserted recording paper.

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 which forms an image by conveying recording paper fed from a paper cassette onto a platen without a paper size detection means.

0002

2. Description of the Related Art In image forming apparatuses such as copying machines, it is necessary to detect the size of fed recording paper. The reason for this is to prevent printing on the blank area of the platen in the case of inkjet method, to prevent unnecessary toner from being deposited on the photosensitive drum in case of electrophotographic method, and to prevent automatic change from an image editing perspective. This is to realize the purpose of making the double function work and prohibiting the image from being moved to a place where there is no paper. Therefore, conventional image forming devices
(1) The special paper size cassette has a cassette size detection means. (Known in conventional machines) (2) The paper feed cassette does not have a paper size detection means,
After paper is fed onto the platen, the width of the paper is detected by scanning the platen with a reflective sensor placed on the ink head carriage. Then, the length of the paper is estimated from the paper width. (3) For recording paper that is manually fed, conventional machines use a position sensor on the manual paper guide to detect the paper size.

0003

[Problems to be Solved by the Invention] The mechanism for detecting paper size without having a paper size detection means in the conventional paper feed cassette described above is to scan the ink head carriage after conveying the recording paper onto the platen. This method has disadvantages in that it takes time to form an image because it moves the paper width detection sequence for paper width detection, and power consumption increases because the carriage is driven extra just to detect the paper width.

An object of the present invention is to detect the paper width of the recording paper conveyed onto the platen from the paper feed cassette, which does not have a paper size detection means, so that it does not take time to form an image, and to detect the paper width. An object of the present invention is to provide an image forming apparatus that does not increase power consumption.

[0005]

[Means for Solving the Problems] The image forming apparatus of the present invention is disposed on a recording paper conveyance path between a paper feed cassette and a platen, detects the presence or absence of passing recording paper, and places the recording paper on the platen. It has one or more paper width sensors that detect the paper width of the transported paper.

[0006]

[Operation] The paper width sensor installed on the recording paper conveyance path between the paper feed cassette and the platen detects the presence or absence of paper that has passed, so the paper width can be detected.

[0007]

Embodiments Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the image forming apparatus of the present invention, FIG. 2 is a partial perspective view of the digital copying machine shown in FIG. 1, and FIG. 3 is a diagram showing the digital copying machine shown in FIG. 2 seen from another angle. 4 is a flowchart of the paper width detection sequence of the CPU 50 in FIG. 1, and FIG. 5 is a partial perspective view of the paper width sensors 307, 308, 3 in FIG.
FIG. 3 is a diagram showing the relationship between the output of No. 09 and the size of recording paper. This image forming apparatus is a digital copying machine that includes an image scanner 10, an image processing section 20, a head driver 301, motor drivers 302, 303, a driver 304, a paper feed sensor 306, paper width sensors 307, 308, 309, a carriage motor 311, and a paper It includes a transport motor 312, a paper feed solenoid 313, a clutch 314, a carriage 315, a manual feed sensor 318, a bubble jet head (hereinafter referred to as a BJ head) 320, a paper feed cassette 340, an operation panel 40, and a CPU 50.

The image scanner 10 acquires image data in 8-bit multi-value format. The image processing unit 20 binarizes the 8-bit image data output by the image scanner 10. A head driver 301 drives a BJ head 320 using binarized image data. Motor driver 302
drives the carriage motor 311. Motor driver 303 drives paper transport motor 312 . Solenoid driver 304 drives paper feed solenoid 313 . The paper feed sensor 306 is a reflective sensor placed at the position shown in FIG. 2, and detects the presence or absence of recording paper passing therethrough. The paper width sensors 307, 308 and 309 are similarly shown in FIG.
These reflective sensors are placed at the positions shown in Figure 5, and are used to detect the presence or absence of passing paper and to detect the size of the transported paper.The relative positions of each paper width sensor are as shown in Figure 5. This is related to the paper width of each size of the recording paper being conveyed. Carriage motor 311 moves carriage 315 over platen 317 via drive belt 316 . An inkjet head cartridge (hereinafter referred to as IJC) 319 includes a group of nozzles that eject ink toward the recording surface of recording paper fed onto a platen 317. Here, in FIG. 3, 315 is a carriage (HC) that holds the IJC 319, and a drive belt 3 that transmits the driving force of the carriage motor 311.
16 and is slidable on two guide shafts 19A and 19B arranged parallel to each other, it is possible to reciprocate across the entire width of the recording paper of the IJC 319. Further, 26 is a head recovery device, which is disposed at one end of the moving path of the IJC 319, for example, at a position opposite to the home position.
The IJC319 is capped by operating the IJC319. IJ by the cap portion 26A of this head recovery device 26
In connection with the capping of the IJC 319, ink is sucked by an appropriate suction means provided in the head recovery device 26 or ink is force-fed by an appropriate pressure means provided in the ink supply path to the IJC 319, and the ink is sucked from the ejection port. Ejection recovery processing such as removing thickened ink inside the nozzle is performed by forcibly discharging the ink. Furthermore, IJC is protected by capping at the end of recording, etc. Further, reference numeral 30 denotes a blade as a wiping member, which is disposed on the side surface of the head recovery device 26 and is made of silicone rubber. The blade 30 is a blade holding member 30A
Like the head recovery device 26, it is operated by the cleaning motor 22 and the transmission mechanism 23, and can be engaged with the ejection surface of the IJC 319. As a result, at an appropriate timing during the recording operation of the IJC 319 or after the ejection recovery process using the head recovery device 26, the blade 30 is projected into the movement path of the IJC 319, and as the IJC 319 moves, the ejection surface of the IJC 319 is This is for wiping off condensation, moisture, dust, etc. BJ head 320 is IJ
It is installed in the C319 and uses thermal energy to form a flying liquid surface to perform inkjet recording.

The typical structure and principle of the BJ head 320 are disclosed in, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740,796. This recording method is applicable to both so-called on-demand type and continuous type. To briefly explain this recording method, a nucleate boiling phenomenon occurs in the liquid (ink) in response to recorded information on an electrothermal transducer placed corresponding to the sheet holding the liquid (ink) and the liquid path. Thermal energy is generated to cause film boiling on the thermally active surface of the recording head by applying at least one drive signal to provide a rapid temperature rise such that the film boiling phenomenon occurs. In this way, bubbles can be formed in one-to-one correspondence with the drive signals applied to the electrothermal transducer from the liquid (ink), which is particularly effective for on-demand recording methods. The growth and contraction of the bubble causes liquid (ink) to be ejected through the ejection hole to form at least one drop. If this drive signal is in the form of a pulse, bubble growth and contraction will occur immediately and appropriately, making it especially suitable for liquids (inks) with excellent responsiveness.
can be achieved, which is more preferable. This pulse-shaped drive signal is described in US Pat. No. 4,463,359;
The one described in the specification of the same No. 4345262 is suitable. Further, if the conditions described in US Pat. No. 4,313,124 concerning the invention regarding the temperature increase rate of the heat acting surface are adopted, even more excellent recording can be performed.

[0011] In addition to the structure of the recording head that combines ejection holes, liquid flow paths, and electrothermal converters (straight liquid flow path or right-angled liquid flow path), there are other structures as described in US Pat. As disclosed in Japanese Patent No. 4,459,600, it also includes a structure in which a heat acting part is disposed in a bending region.

In addition, Japanese Patent Laid-Open No. 123670 of 1982 discloses a configuration in which a common slit is used as a discharge hole for a plurality of electrothermal converters, and a method for absorbing pressure waves of thermal energy is disclosed. The present invention is also effective in a configuration based on Japanese Patent Application Laid-open No. 138461 of 1981, which discloses a configuration in which the openings correspond to the discharge portions.

Further, as a recording head to which the present invention can be effectively utilized, there is a full-line type recording head having a length corresponding to the maximum width of a recording medium that can be recorded by a recording apparatus. This full line head is one that has a full line configuration by combining multiple recording heads mentioned above,
It may be a single full-line recording head formed integrally.

In addition, a replaceable chip-type recording head that is attached to the apparatus main body enables electrical connection with the apparatus main body and ink supply from the apparatus main body, or an integrated recording head itself. It is also effective when using a cartridge-type recording head provided with a conventional method. B
It is preferable to add recovery means for the recording head, preliminary auxiliary means, etc. to the recording apparatus in which the J head is used, since this can make the recording apparatus even more stable. Specifically, these include preheating of the recording head using a capping means, a cleaning means, a pressurizing or suction means, an electrothermal transducer or a separate heating element, or a combination thereof. It is also effective to add a means for performing a preliminary ejection mode in which ejection is performed separately from printing in order to perform stable printing.

Furthermore, the recording mode of the recording device is not limited to a mode in which only mainstream colors such as black are recorded, but the recording head may be configured either as an integral unit or as a combination of multiple units. However, it is also extremely effective for devices having at least one of multiple colors of different colors or full colors by mixing colors.

Although liquid ink is used in the BJ head 320, it is also possible to use ink that is solid at room temperature or ink that is soft at room temperature. In the above-mentioned inkjet devices, the temperature of the ink itself is generally adjusted within the range of 30°C to 70°C to keep the viscosity of the ink within a stable ejection range. It is sufficient if the ink is liquid.

In addition, the purpose is to actively prevent excessive temperature rise of the head and ink due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent evaporation of the ink. It is also possible to use an ink that solidifies when left as it is. In any case, some types of ink are liquefied by the application of thermal energy in accordance with the recording signal and ejected as liquid ink, and some are already solidified by the time they reach the recording medium. It is also applicable to use ink that has the property of

[0018] Such ink is disclosed in Japanese Patent Application Laid-Open No. 54-568.
47 or Japanese Patent Application Laid-Open No. 60-71260, the material is held as a liquid or solid in the recesses or through-holes of a porous sheet and faces the electrothermal converter. It can also be used as a form. The most effective method for each of the above-mentioned inks is one that implements the above-mentioned film boiling method.

Paper transport motor 312 rotates paper feed roller 330. The paper feed solenoid 313 operates a clutch 314 to control the transmission of rotational force of the paper transport motor 312 to the paper feed roller 330. The manual feed sensor 318 is a reflective sensor placed at the position shown in FIG. 1, and is a sensor for detecting the presence or absence of passing paper and detecting that paper is being manually fed onto the platen 317 from direction B. be. The paper feed roller 330 conveys the recording paper in the paper feed cassette 340 onto the conveyance path.

The CPU 50 sends image data read by the image scanner 10 to the image processing section 20 and the head driver 3.
BJ head 32 mounted on IJC319 via 01
0 is used to print on the recording paper, and the paper width of the recording paper is detected according to the sequence shown in FIG.

That is, when a copy start key (not shown) on the operation panel 40 is pressed, the CPU 50 drives the paper conveyance motor 312 and simultaneously drives the paper feed solenoid 313 (step 1). As a result, the paper feed roller 330 is rotated via the clutch 314, and the paper feed cassette 3
40, the paper is sent out on the conveyance path in the direction F shown in FIG. When the recording paper is conveyed by a predetermined length, the paper feed sensor 3
06, and the presence or absence of passing paper is detected (step 2). Thereafter, the paper is conveyed by a predetermined length until the leading edge reaches a predetermined position A. This starts the timer when the paper passes the paper feed sensor 306 (step 3), and when a predetermined time has elapsed (step 4), stops the paper feed solenoid 313 and paper transport motor 312 (step 5). Stop at position A. At this time, the paper is positioned on paper width sensors 307, 308, and 309. C
As shown in Table 1, the PU determines the paper width according to the combination of the outputs of the paper width sensors 307, 308, and 309, as shown in Table 1.

[0022]

[Table 1] For example, in the case of a combination where the output of the paper width sensor 307 is recording paper present, the output of the paper width sensor 308 is no recording paper, and the output of the paper width sensor 309 is no recording paper, the paper width of the conveyed recording paper is It is detected that the width of the paper is A5.

Next, when recording paper is inserted onto the platen 317 from direction B in FIG. 1, when the paper passes over the manual feed sensor 318, the manual feed sensor 31 detects this.
8 notifies the CPU 50 that manual feeding has been performed,
The CPU 50 rotates the paper transport motor 312 in the opposite direction to the above-mentioned direction to transport the recording paper in the B direction. Then, when the edge of the paper passes the paper feed sensor 306, the rotation is reversed. Then, as described above, the leading edge of the paper is stopped at position A by timer management. At this time, since the paper is located above the paper size sensors 307, 308, and 309, the CPU
50 detects the paper width based on a combination of outputs from paper width sensors 307, 308, and 309 in the same way as when paper is fed from the paper feed cassette 340.

Here, the paper feed sensor 306 and the manual feed sensor 3
18. The paper width sensors 307, 308, and 309 are not limited to reflective types, but may also use photointerrupters or microswitches via levers. It may also serve as one of the following.

In the digital copying machine of this embodiment, the paper width detection sequence is not activated after paper feeding, so the time required to form an image is shortened, and the inkjet carriage is not scanned to detect the paper width, so power consumption is not increased. .

[0026]

As described above, the present invention detects the paper width by arranging one or more paper width sensors on the recording paper conveyance path to detect the presence or absence of passing recording paper. Since the paper width can be detected before the recording paper is conveyed onto the platen, there is no need to run the sequence that scans the ink head carriage after conveyance, reducing the time until image formation, and the carriage can be scanned to detect the paper width. This has the effect of not increasing the power consumption of the drive motor.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of an image forming apparatus of the present invention.

FIG. 2 is a partial perspective view of the digital copying machine of FIG. 1;

FIG. 3 is a partial perspective view of the digital copying machine of FIG. 2 seen from another angle.

FIG. 4 is a flowchart of a paper width detection sequence of the CPU 50 in FIG. 1;

5 is a diagram showing the relationship between the outputs of paper width sensors 307, 308, and 309 in FIG. 1 and the size of recording paper.

[Explanation of symbols]

1, 2,..., 7 Step 10 Image scanners 19A, 19B Guide shaft 20 Image processing section 22 Cleaning motor 23 Transmission mechanism 26 Cap member 26A Cap section 30 Blade 30A Blade holding mechanism 40 Operation panel 50 CPU 301 Head drivers 302, 303 Motor driver 304
Solenoid driver 306 Paper feed sensors 307, 308, 309 Paper width sensor 311
Carriage motor 312 Paper conveyance motor 313 Paper feed solenoid 314 Clutch 315 Carriage 316 Drive belt 317 Platen 318 Manual feed sensor 319 Inkjet cartridge (IJC)
320 BJ head 330 Paper feed roller 340 Paper feed cassette

Claims (6)

[Claims] 1. In an image forming apparatus that forms an image by conveying recording paper fed from a paper cassette without paper size detection means onto a platen, the recording paper between the paper cassette and the platen is An image forming apparatus comprising one or more paper width sensors disposed on a conveyance path to detect the presence or absence of passing recording paper and detect the paper width of the recording paper conveyed onto the platen. . 2. The apparatus according to claim 1, further comprising a manual paper feeding mechanism, wherein recording paper fed by the manual paper feeding mechanism is transported along the transport path, and the paper width is detected by a paper width sensor on the transport path. image forming device. 3. The paper width sensor according to claim 1, further comprising a paper width sensor that also serves as a paper feed sensor for detecting the recording paper fed from the paper feed cassette and the manual paper feed mechanism and generating paper transport control timing for the transport path. The image forming apparatus described above. 4. The image forming apparatus according to claim 1, further comprising a liquid jet recording head in which the energy generating element is an electrothermal converter that generates thermal energy as energy. 5. Claim 4, wherein the liquid jet recording head is of a full line type in which a plurality of ink ejection ports are provided over the entire width of a recording area of recording paper as a recording medium.
The image forming apparatus described in . 6. A liquid jet recording head in which an ink discharge port is provided opposite to a recording surface of recording paper and has an electrothermal converter that generates thermal energy as an energy generating element, and the head is mounted. The image forming apparatus according to claim 4, further comprising a liquid jet recording device comprising at least a member for.