JP2021084783A - Image forming apparatus and transfer control method of the image forming apparatus - Google Patents

Abstract

To suppress a misalignment of image formation on a recording medium even when a tip of the recording medium is tilted.SOLUTION: An image forming apparatus 100 includes: a line sensor 2 that detects a position of a side edge of a recording medium in a direction orthogonal to a transport direction; a plurality of tilt sensors 1 that are arranged apart from each other in an orthogonal direction and detect a transport timing of the recording medium in the transport direction; a tilt calculation unit 11 that calculates the tilt of a tip of the recording medium in the transport direction with respect to the orthogonal direction based on a plurality of transport timings; a corner position calculation unit 12 that calculates a position of a corner where the side edge and the tip of the recording medium intersect based on the position of the side edge and the tilt of the tip; and a transport control unit 15 that controls a position at which image formation is started on the recording medium based on the position of the corner, or controls a transport speed of the recording medium based on the position of the corner.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an image forming apparatus and a transfer control method for the image forming apparatus.

Patent Document 1 discloses a technique for transporting a recording medium in parallel with the transport direction. The image forming apparatus of Patent Document 1 includes a plurality of line sensors called CIS (Contact Image Sensor), and the recording medium is provided by the plurality of line sensors in the width direction of the recording medium, that is, in the direction orthogonal to the transport direction (hereinafter, orthogonal direction). By detecting the position of the side end of, the amount of positional deviation in the width direction is calculated, and the recording medium is corrected so as to be conveyed in parallel with the conveying direction.

However, in the prior art of Patent Document 1, when the tips of a plurality of recording media to be corrected in the transport direction in each transport direction are tilted at different angles with respect to the orthogonal direction, the transport directions of the respective recording media The position to detect the tip is different. Since the width of the margin portion from the tip of the recording medium to the position of image formation on the recording medium is set to be the same for each of the plurality of recording media, as described above, the tip is caused by the difference in the inclination of the tip. When the detection position of the image is different for each recording medium, there is a problem that the position of image formation on each recording medium is deviated.

In view of the above problems, the present disclosure can suppress the misalignment of image formation on the recording medium even when the tip of the recording medium is tilted.

In view of the above problems, the image forming apparatus according to the present disclosure is arranged apart from each other in the direction orthogonal to the side edge position detecting unit that detects the position of the side edge of the recording medium in the direction orthogonal to the transport direction. A tilt calculation for calculating the tilt of the tip of the recording medium in the transport direction with respect to the orthogonal direction based on the plurality of transport timing detection units that detect the transport timing of the recording medium in the transport direction and the plurality of transport timings. Based on the portion, the position of the side end, and the inclination of the tip, the corner position calculation unit for calculating the position of the corner where the side end and the tip of the recording medium intersect, and the position of the corner are determined. A control unit for controlling the position at which image formation is started on the recording medium with reference to the reference, or controlling the transport speed of the recording medium with reference to the position of the corner portion is provided.

According to the present disclosure, there is an effect that the positional deviation of image formation on the recording medium can be suppressed even when the tip of the recording medium is tilted.

The figure which shows the structural example of the image forming apparatus which concerns on this embodiment. The figure which shows the arrangement example of a line sensor and a tilt detection sensor, etc. Flow chart for explaining the operation of the image forming apparatus The figure which shows the state which widened the distance between two tilt sensors The figure for demonstrating the operation of the switching part of a control part The figure which shows the modification of the image forming apparatus which concerns on this embodiment. The figure which shows the two overlapping recording media and the image position formed on these recording media. The figure which shows the image position formed on one recording medium The figure which shows the image position formed on the other recording medium The figure which shows the cutting position of two overlapping recording media The figure for demonstrating the operation when the image forming apparatus which concerns on a comparative example is used. The figure which shows the hardware configuration of an image forming apparatus

Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration example of an image forming apparatus according to the present embodiment. It includes a plurality of tilt sensors 1-1 to 1-N (N is an integer of 1 or more), a line sensor 2, and a control unit 10.

Each of the plurality of tilt sensors 1-1 to 1-N is used to detect the tilt of the tip of the sheet-shaped recording medium in the transport direction. The recording medium is, for example, thick paper, postcard, envelope, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, OHP sheet, or the like. The transport direction is equal to the sub-scanning direction.

Each of the plurality of tilt sensors 1-1 to 1-N is a transport timing detection unit that is arranged apart from each other in the orthogonal direction of the recording medium and detects the transport timing of the recording medium in the transport direction. The orthogonal direction is equal to the main scanning direction. Hereinafter, when each of the plurality of tilt sensors 1-1 to 1-N is not distinguished, it may be referred to as "tilt sensor 1".

The line sensor 2 is a side end position detecting unit that detects the position of the side end in the orthogonal direction of the recording medium. The line sensor 2 is, for example, CIS. The CIS is a sensor that directly reads an image with a linear sensor via a lens by using a plurality of LEDs (Light Emitting Diodes) arranged linearly along an orthogonal direction for the purpose of downsizing the device. Since the structure of CIS is known as disclosed in Non-Patent Document 1, Non-Patent Document 2, etc., detailed description thereof will be omitted. The line sensor 2 is not limited to CIS, and may be any sensor that can detect the position of the side end of the recording medium in the orthogonal direction. Hereinafter, the position of the side edge of the recording medium may be simply referred to as the “side edge position”.

The control unit 10 includes an inclination calculation unit 11, a corner position calculation unit 12, an inclination correction unit 13, a switching unit 14, and a transfer control unit 15.

The tilt calculation unit 11 calculates the tilt of the tip of the recording medium in the transport direction with respect to the orthogonal direction based on the transport timings detected by the plurality of tilt sensors 1, and obtains information indicating the calculated tip tilt value. Input to the unit position calculation unit 12.

The corner position calculation unit 12 calculates the position of the corner where the side end and the tip of the recording medium intersect based on the side end position detected by the line sensor 2 and the inclination of the tip, and calculates the position of the corner. Information indicating the position is input to the transport control unit 15.

The tilt correction unit 13 corrects the inclination of the side edge of the recording medium with respect to the transport direction so that the side edge of the recording medium is parallel to the transport direction based on the side edge position detected by the line sensor 2, and after correction. Information indicating the value of the inclination of the side edge of the recording medium is input to the transport control unit 15.

Based on the recording medium size information 16 which is information indicating the size of the recording medium, the switching unit 14 generates switching information which is information for switching the calculation of the tip inclination by the inclination calculation unit 11 from the valid state to the invalid state. It is transmitted to the inclination calculation unit 11.

The transport control unit 15 inputs information indicating the position of the corner portion from the corner portion position calculation unit 12 and the tilt value of the side edge of the recording medium after correction from the tilt correction unit 13, and positions the corner portion. The position at which image formation is started on the recording medium is controlled with reference to, or the transport speed of the recording medium is controlled with reference to the position of the corner portion.

Next, the operation of the image forming apparatus 100 will be described with reference to FIG. 2 and the like. FIG. 2 is a diagram showing an arrangement example of a line sensor, an inclination detection sensor, and the like. FIG. 3 is a flowchart for explaining the operation of the image forming apparatus 100.

In the recording medium 200, the line sensor 2 is arranged in the direction orthogonal to the front end 201, which is the front end of the recording medium 200 with respect to the transport direction, and the rear end 202, which is the rear end of the recording medium 200 with respect to the transport direction. The side end 203 on the side to be sewn and the side end 204 on the side opposite to the side end 203 in the orthogonal direction are provided. The tip 201 of the recording medium 200 is slightly tilted with respect to the orthogonal direction, and this tilt is different from each other in each of the plurality of recording media 200 to be conveyed.

As shown in FIG. 2, the tilt sensor 1-1 and the tilt sensor 1-2 are arranged so that their positions are equal to each other in the transport direction. Further, the tilt sensor 1-1 and the tilt sensor 1-2 are arranged so as to face the recording medium 200 so as to be separated from each other in the orthogonal direction. The image forming position 210 shown by the thick solid line is the printing position of the image on the recording medium 200.

When the recording medium 200 is conveyed toward the tilt sensor 1-1 and the tilt sensor 1-2 with the tilt sensor 1-1 and the tilt sensor 1-2 arranged in this way, the line sensor 2 first informs the recording medium 200. The position of the side end 203 is detected (step S1).

When the position of the side end 203 is detected, the tilt correction unit 13 of the control unit 10 inputs the position of the side end 203 from the line sensor 2, and the side end 203 of the recording medium 200 becomes parallel to the transport direction. As described above, the inclination of the side end 203 with respect to the transport direction is corrected (step S2).

When the recording medium 200 reaches the tilt sensor 1-1 and the tilt sensor 1-2, the tilt sensor 1-1 and the tilt sensor 1-2 detect the position of the tip 201 of the recording medium 200 (step S3).

Since the tip 201 of the recording medium 200 is tilted, the detection timing of the tip 201 of the recording medium 200 is different for each of the tilt sensor 1-1 and the tilt sensor 1-2. In the example of FIG. 2, the position of the tip 201 of the recording medium 200 is detected in the order of the tilt sensor 1-1 and the tilt sensor 1-2. The information indicating the position of the tip 201 detected by the tilt sensor 1-1 and the tilt sensor 1-2, respectively, is input to the tilt calculation unit 11 as information indicating the transport timing.

The inclination calculation unit 11 in which each transfer timing is input calculates the inclination θ of the tip 201 with respect to the orthogonal direction according to the following equation (1), for example (step S4). In FIG. 2, the angle formed by the two sides of the right triangle having the origin SP as the apex and the two sides in contact with the apex are detected by the tilt sensor 1-2 in the tip 201 of the recording medium 200. Of the three sides of a right triangle whose apex is a certain position, the angle formed by the two sides in contact with the apex is similar. Therefore, the inclination θ can be obtained from any of these angles.

θ = tan ^-1 b / a ... (1)

Equation a in equation (1) represents the distance from the tilt sensor 1-1 to the tilt sensor 1-2 in the orthogonal direction. The distance a is a known value because it is determined by the sensor layout. The distance a is the distance from the tilt sensor 1-1 to the tilt sensor 1-2 in the orthogonal direction measured in the production process, and information is input (corrected) so that the measured value becomes a more accurate value. But it may be.

Equation b in equation (1) represents the distance in the transport direction from the position where the transport timing is detected by the tilt sensor 1-1 to the position where the transport timing is detected by the tilt sensor 1-2. The distance b is calculated from the time difference between the two transport timings and the calculated time difference and the transport speed of the recording medium 200. The inclination calculation unit 11 that has calculated the inclination θ inputs information representing the inclination θ to the corner position calculation unit 12.

The corner position calculation unit 12 calculates a virtual line VL1 extending the tip 201 inclined at the inclination θ based on the information indicating the inclination θ, and further extends the side end 203 based on the information indicating the side end position. Calculate the virtual line VL2. Then, the corner portion position calculation unit 12 calculates the position where the virtual line VL1 and the virtual line VL2 intersect as the position where the corner portion where the side end 203 and the tip 201 of the recording medium 200 intersect exists (step S5).

The transport control unit 15 performs transport control using the corner position calculated by the corner position calculation unit 12 as the origin SP for starting image formation on the recording medium 200 (step S6). The transport control includes, for example, increasing the transport speed of the recording medium 200, slowing down the transport speed of the recording medium 200, shifting the image formation position, and the like. The start position of image formation is, for example, a position separated from the origin SP by a certain distance (for example, several mm to several cm) with respect to the transport direction. Further, when controlling the transport speed, the transport control unit 15 can align the sub-scanning position with the origin SP of the recording medium 200.

The alternate long and short dash line in FIG. 2 represents the tip 201a of the recording medium 200 that has passed through the origin SP and has been cut along a line parallel to the orthogonal direction. If the side end 203 of the recording medium 200 and the origin SP are aligned and cut, it is possible to obtain a plurality of recording media 200 having the same start position of image formation regardless of the shape of the recording medium 200.

Next, a case of detecting the tip position of the recording media 200 having different sizes will be described.

FIG. 4 is a diagram showing a state in which the distance between the two tilt sensors is widened. When determining the inclination of the tip 201 of the recording medium 200, the amount of deviation of the sub-scanning position becomes relatively large when the distance between the plurality of inclination sensors 1 is increased. Therefore, the inclination of the tip 201 of the recording medium 200 is calculated. Accuracy is improved.

However, the size of the recording medium 200 to be conveyed varies. Therefore, for example, in order to obtain the inclination of the tip 201 of all the recording media 200 from the recording medium 200 having a width of several cm in the orthogonal direction to the recording medium 200 having a width of several tens of cm, the plurality of recording media 200 having different sizes are used. It is necessary to install a large number of tilt sensors 1 so as to correspond to all of them, which is not realistic.

Therefore, among a plurality of recording media 200 having different sizes, a tilt sensor 1-1 is provided at a position closer to the side end 204 in the orthogonal direction with reference to the recording medium 200 having the smallest size (for example, postcard size), and the tilt sensor 1-1 is provided in the orthogonal direction. It is preferable to provide the tilt sensor 1-2 at a position closer to the side end 203 of the above. As described above, the reason why the tilt sensor 1 is provided at the position closer to the side end 204 and the position closer to the side end 203 is that the small-sized recording medium 200 tends to have a shorter distance b in the above equation (1). Therefore, the distance b is increased by increasing the distance a between the plurality of tilt sensors 1.

Next, the operation of the switching unit 14 of the control unit 10 will be described with reference to FIG.

FIG. 5 is a diagram for explaining the operation of the switching unit of the control unit. As shown in FIG. 5, the positions of the plurality of tilt sensors 1 are fixed with respect to the recording media 200A and the recording medium 200B having different sizes. The switching unit 14 switches whether to enable or disable the calculation of the corner position by the corner position calculation unit 12 according to the respective sizes of the recording medium 200A and the recording medium 200B.

For example, when two tilt sensors 1-1 and a tilt sensor 1-2 are arranged so as to correspond to a small size (for example, postcard size) recording medium 200B, the main scanning length of the small size recording medium 200B is It is shorter than the main scanning length of the large-sized recording medium 200A. Therefore, the sub-scanning position shift detected by the two tilt sensors 1-1 and the tilt sensor 1-2 becomes small, and the tilt detection becomes difficult. Therefore, the arrangement positions of the two tilt sensors 1-1 and the tilt sensor 1-2 are set so as to match the large-sized recording medium 200A, and then, in the large-sized recording medium 200A, the two tilt sensors 1- It is preferable that 1 and the tilt sensor 1-2 are used, and one of the tilt sensors (tilt sensor 1-2 in FIG. 5) is used in the small-sized recording medium 200B. In the latter case, the position where one of the tilt sensors (tilt sensor 1-2 in FIG. 5) is arranged is preferably the image formation position reference, that is, the position closer to the origin SP as much as possible.

The switching unit 14 is a recording medium 200A in which the recording medium size information 16 is input and the position of the tip 201 is detected by both the two tilt sensors 1-1 and the tilt sensor 1-2. It is determined whether the recording medium 200B has or the position of the tip 201 is detected by only one of them. The recording medium size information 16 is set in advance in a predetermined memory as, for example, table information in which identification information for identifying a plurality of recording media 200 having different sizes and information indicating the respective sizes are associated with each other. There is.

When the switching unit 14 determines that the recording medium 200B is used, the switching unit 14 generates switching information which is information for switching the tip inclination calculation by the inclination calculation unit 11 from a valid state to an invalid state. As a result, the calculation of the tip inclination is stopped, and the calculation of the corner position in the corner position calculation unit 12 is also stopped. Therefore, the transfer control is performed only by the tilt sensor 1-2.

In this case, the inclination of the tip 201 of the recording medium 200B cannot be detected, but the tip detection position is close to the image formation position reference, so that the amount of sub-scanning deviation can be suppressed to a small value. In the figure, the distance from the tilt sensor 1-1 to the origin SP is α, the distance from the tilt sensor 1-2 to the origin SP is β, and when the distance α and the distance β are compared, the distance β is the sub. It is close to the origin SP in the scanning direction.

By using the switching unit 14, the inclination of the tip of each of the recording media 200 of different sizes can be calculated with high accuracy.

FIG. 6 is a diagram showing a modified example of the image forming apparatus according to the present embodiment. As shown in FIG. 6, the distance between the plurality of tilt sensors 1 can be secured for both the recording medium 200A such as SRA3, which is the maximum size as a standard, and the small size recording medium 200B such as a postcard. Four tilt sensors 1 may be arranged.

In this case, the tilt calculation unit 11 calculates the tilt of the large-sized recording medium 200A by using the tilt sensor 1-1 and the tilt sensor 1-4, and the tilt calculation unit 11 calculates the tilt of the small-sized recording medium 200B. Calculates the tilt using the tilt sensor 1-2 and the tilt sensor 1-3.

In this way, by using the tilt sensors 1 near both ends of the recording medium 200 from among the plurality of tilt sensors 1 according to the size of the recording medium 200, the plurality of tilt sensors 1 used for tilt calculation are used. The distance between them becomes long, and the inclination of the tip of each of the recording media 200 having different sizes can be calculated with high accuracy.

Next, the effect of the image forming apparatus 100 according to the present embodiment will be described with reference to FIGS. 7 to 11.

FIG. 7 is a diagram showing two overlapping recording media and image positions formed on these recording media. The tip 201 of the recording medium 200-1 shown by the solid line and the tip 201 of the recording medium 200-2 shown by the broken line are inclined at different angles with respect to the orthogonal direction. The square part indicated by the thick solid line indicates the image formation position. The symbol "x" is a reference point at which image formation is started.

FIG. 8 is a diagram showing an image position formed on one recording medium, FIG. 9 is a diagram showing an image position formed on the other recording medium, and FIG. 10 is a diagram showing a cutting position of two overlapping recording media. is there.

As shown in FIGS. 8 and 9, by forming an image with the lower left corners of the recording media 200-1 and 200-2 as the origin SP, the image can be aligned with respect to the origin P. Will be done.

By superimposing the lower left origin SP on the recording media 200-1 and 200-2 printed by this method and performing cutting, the respective image formation positions are set to the same position. Further, when cutting, the cutting is performed with the origin SP at the lower left abutting against the cutting machine, so that the reference position and the cutting position are closer to each other with the abutting side as a reference, and the recording media 200-1, 200- It is also possible to obtain the effect that the misalignment of each of 2 is unlikely to occur.

FIG. 11 is a diagram for explaining an operation when the image forming apparatus according to the comparative example is used. In the image forming apparatus according to the comparative example, since the inclination of the tip of the recording medium 200 is not calculated and the corner position is not calculated, the image forming position with reference to the origin SP shown in FIG. 11 is not set. Therefore, in the plurality of recording media 200 having different inclinations of the tip 201, the positions of the tip margins are different from each other. As a result, when these recording media 200 are superposed, for example, the image forming position 210 (normal solid line) formed on the recording medium 200 having an inclination at the tip 201 and the recording medium 200 not tilting at the tip 201 are formed. The image formation position 210 (thick solid line) does not overlap.

On the other hand, the image forming apparatus 100 according to the present embodiment includes a tilt calculation unit that calculates the tilt of the tip in the transport direction of the recording medium with respect to the orthogonal directions based on a plurality of transport timings, and the side end positions and the tip. It is provided with a corner position calculation unit that calculates the position of the corner where the side edge and the tip of the recording medium intersect based on the inclination of. With this configuration, the image formation position can be set with each corner of the recording medium 200 having a different inclination as the origin SP. Therefore, for example, when a plurality of recording media on which an image is formed are cut in a stacked state, the width from the tip of the cutting medium to the image can be made equal.

FIG. 12 is a diagram showing a hardware configuration of the image forming apparatus. The image forming device 100 includes a control device 110, a display device 120, a main storage device 130, an operation input device 140, an external storage device 150, a printing device 160, an image reading device 170, and a network device 180.

The main storage device 130 is composed of a RAM (Random Access Memory) or the like that functions as a work area for a program executed by the control device 110. The external storage device 150 is, for example, a hard disk drive, and stores various control programs, application programs, image data, and the like. The control device 110 loads and executes necessary programs and the like from the external storage device 150 to the main storage device 130, and controls the entire image forming device 100 through the bus 20. The control device 110 performs processing for realizing the functions of, for example, a multifunction device, a copying machine, a scanner, a facsimile, and a printer in the image forming apparatus 100. The operation input device 140 is a user interface that accepts a user's operation and provides information to the user by displaying information corresponding to the operation on a screen (not shown). The network device 180 is a communication interface that connects the image forming device 100 to the network.

1,1-1,1-2,1-3, 1-4: Tilt sensor 2: Line sensor 10: Control unit 11: Tilt calculation unit 12: Corner position calculation unit 13: Tilt correction unit 14: Switching unit 15 : Transport control unit 16: Recording medium size information 100: Image forming apparatus 200, 200-1, 200-2, 200A, 200B: Recording medium 201, 201a: Front end 202: Rear end 203, 204: Side end 210: Image forming position

Japanese Unexamined Patent Publication No. 2016-175776

"Contact image sensor" [Searched on November 11, 1991] Internet <URL: https://compo.canon/ja/product/cis/> "Adhesion image sensor (CIS)" [Searched on November 11, 1991] Internet <URL: https://www.mitsubishielectric.co.jp/device/device/cis/>

Claims (5)

A side end position detection unit that detects the position of the side end of the recording medium in a direction orthogonal to the transport direction,
A plurality of transport timing detection units that are arranged apart from each other in the orthogonal directions and detect the transport timing of the recording medium in the transport direction.
A tilt calculation unit that calculates the tilt of the tip of the recording medium in the transport direction with respect to the orthogonal directions based on the plurality of transport timings.
A corner position calculation unit that calculates the position of a corner where the side end and the tip of the recording medium intersect based on the position of the side end and the inclination of the tip.
A control unit that controls the position at which image formation is started on the recording medium with reference to the position of the corner, or controls the transport speed of the recording medium with reference to the position of the corner.
An image forming apparatus comprising. The image forming apparatus according to claim 1, further comprising a tilt correction unit that corrects the inclination of the side end with respect to the transport direction so that the side end is parallel to the transport direction based on the position of the side end. Claim 1 or 2 includes a switching unit for switching the calculation of the corner position by the corner position calculation unit from a valid state to an invalid state based on the recording medium size information which is information indicating the size of the recording medium. The image forming apparatus according to the description. Based on the recording medium size information, which is information indicating the size of the recording medium, the inclination calculation unit detects two transfer timings arranged near both ends of the recording medium from among the plurality of transfer timing detection units. The image forming apparatus according to any one of claims 1 to 3, which calculates the inclination of the tip based on the transport timing detected by the unit. A step of detecting the position of the side edge of the recording medium in a direction orthogonal to the transport direction, and
A step of detecting the transfer timing of the recording medium in the transfer direction, which are arranged apart from each other in the orthogonal direction.
A step of calculating the inclination of the tip in the transport direction of the recording medium with respect to the orthogonal directions based on the plurality of transport timings.
Based on the position of the side end and the inclination of the tip, the step of calculating the position of the corner portion where the side end and the tip of the recording medium intersect is calculated.
A step of controlling the position at which image formation is started on the recording medium with reference to the position of the corner, or a step of controlling the transport speed of the recording medium with reference to the position of the corner.
A transfer control method for an image forming apparatus including.

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