JP2008221770A - Image forming apparatus - Google Patents

Abstract

Provided is a conveying unit capable of achieving stable sheet conveyance regardless of the diameter of roll paper, and an image forming apparatus capable of stable image formation.
In order to achieve stable sheet conveyance regardless of the diameter of roll paper, in an image forming operation for forming an image, the conveyance speed of a long sheet by a roller pair is switched at least once in the middle of one roll length. It is done.
[Selection] Figure 1

Description

  The present invention relates to an image forming apparatus that performs recording on a roll-shaped sheet material (roll paper) around which a long sheet is wound, and relates to an image forming apparatus that can change the conveyance speed of the sheet material.

  In recent years, image forming apparatuses compatible with roll paper have begun to spread widely, centering on inkjet printers.

  For example, the configuration of the image forming apparatus described in Patent Document 1 is characterized in that roll paper feed is realized with a simple configuration that enables loading of roll paper in a conventional cut paper compatible inkjet printer paper feed unit.

  The advantage of an image forming apparatus that supports roll paper as compared to an image forming apparatus that supports cut paper is that when performing continuous image formation of a predetermined size, it is not necessary to separate the sheet material page by page, and separation or poor feeding Therefore, the continuous image forming apparatus can be stably operated.

Other image forming apparatus configurations that support roll paper are disclosed in Patent Literature 2, Patent Literature 3, Patent Literature 4, Patent Literature 5, Patent Literature 6, and Patent Literature 7.
Japanese Patent No. 3714058 JP 2002-137854 A JP 2002-273957 A JP 2002-274742 A Japanese Patent Laid-Open No. 2002-307808 JP 2002-362804 A JP 2002-362805 A

  However, in the image forming apparatus that realizes roll paper with the above-described simple structure, when handling a longer roll paper having a longer length (increasing the capacity of the roll paper), the sheet material is transported when being pulled out of the roll paper. The load increases.

  Further, slipping is likely to occur with the main roller pair responsible for image formation, which makes it difficult to maintain stable and highly accurate roll paper conveyance.

  Accordingly, the present inventor aims to provide a conveying unit that can achieve stable sheet conveyance regardless of the diameter of the roll paper, and to provide an image forming apparatus capable of stable image formation.

A sheet feeding unit that accommodates roll paper wound with a long sheet, an image forming unit that forms an image on the surface of the long sheet conveyed from the sheet feeding unit, and a long sheet on which the image has been formed is cut. A sheet material conveyance path in which a cutter unit and a paper discharge unit are sequentially arranged in the sheet material conveyance direction, and a long sheet of roll paper stored in the sheet feeding unit is fed while being pulled out to the image forming unit. An image forming apparatus comprising: a pair of rollers configured to have a conveying unit disposed between a paper feeding unit and the image forming unit so as to face the image forming unit;
The conveying speed of the long sheet in an image forming operation for performing image formation is switched at least once in the middle of one roll length.

  According to the image forming apparatus of the present invention, even when a large-diameter roll paper that requires a larger gripping force is mounted on the paper feeding unit, it is possible to maintain a highly accurate sheet material feeding accuracy.

  Therefore, it is possible to reduce the number of roll paper exchanges that occur during mass page printing, and there is an effect that the productivity of the user can be improved.

[Device configuration]
FIG. 5 is a perspective view showing the configuration of the ink jet printer according to the present embodiment.

  The ink jet printer includes a paper feed motor 13 and a carriage motor 3. The paper feed motor 13 is a motor for feeding the roll paper 1 in the sub-scanning direction Y.

  The paper feed motor 13 rotationally drives the line feed roller 10 to form a roller pair with the pinch roller 12 as a driven roller by a timing belt (not shown).

  The encoder film 11 is integrated with the line feed roller 10, and the rotation amount of the line feed roller is feedback-controlled by an encoder sensor (not shown) for reading slits on the entire circumference of the encoder film.

  The carriage motor 3 is a motor for moving the recording head 8 in the main scanning direction X of the roll paper 1. The carriage 6 moves left and right along the main scanning direction X of the roll paper 1.

  A pulley 4 is provided on the rotation shaft of the carriage motor 3. A timing belt 5 is stretched around the pulley 4, and a carriage 6 is connected to the timing belt 5.

  As a result, the carriage motor 3 rotates in the forward and reverse directions, whereby the carriage 6 is guided by the guide 9 and moves in parallel over the platen 14.

  A recording head 8 having a nozzle array for discharging black or color ink is provided on the surface of the carriage 6 facing the roll paper 1. Each nozzle receives ink supplied from the ink cartridge 7 and drops ink droplets onto the roll paper 1. To print characters and images.

  The operation of the carriage 6 reciprocating in the main scanning direction X and the operation of the line feed roller 10 for conveying the roll paper 1 in the sub-scanning direction Y while pulling out the roll paper 1 by a predetermined amount are alternately operated to achieve the desired image formation. To do.

  A rotary cutter 15 and a cutter lower guide 16 arranged downstream of the platen 14 in the sheet conveying direction are for cutting the roll paper 1 on which image formation has been completed between pages of a predetermined length.

  The rotary cutter 15 reciprocates in the main scanning direction X along a guide (not shown) for each page where the roll paper 1 is attached or detached or image formation is completed on the roll paper 1.

  In the non-printing area of the carriage 6, a capping device 20 for sealing the nozzle openings of the recording head 8 during non-printing and a pump unit 21 having a pump motor are provided.

  When the carriage 6 moves from the printing area to the non-printing area, the carriage 6 comes into contact with a lever (not shown), the capping device 20 moves upward, and the nozzle row of the recording head 8 is sealed.

  The recording head 8 is sealed when the nozzle opening row of the recording head 8 is not clogged or when ink is forcibly ejected from the recording head 8 after the ink cartridge 7 is replaced. In this state, the pump unit 21 is operated.

  The ink is sucked out from the nozzle opening row by the negative pressure from the pump unit 21.

  As a result, dust and paper dust adhering to the vicinity of the nozzle opening row are washed, and air bubbles in the recording head 8 are discharged to the cap 22 together with the ink.

  FIG. 6 is a cross section AA of the printer in FIG.

  The line feed roller 10 that conveys the roll paper 1 in the sub-scanning direction Y while pulling out a predetermined amount at a time is always carrying the conveyance load Fr, and is stable without slipping the sheet material with the conveyance force Ff generated by the grip force. We must continue to maintain high-precision conveyance of roll paper.

  The larger the roll paper, the greater the rotational inertia force. The pull-out load Fr is large in the initial state of the large-diameter roll paper, and gradually decreases as the roll paper is consumed, so the fluctuation range of the pull-out load Fr increases.

  The roll paper diameter sensor 23 is disposed in the paper feed unit, and can detect the remaining amount of the roll paper 1 or detect the removal of the roll paper 1 by measuring the distance to the outer periphery of the roll. Thus, the roll paper 1 having the maximum diameter φDmax can be loaded into the paper feeding unit.

  The roll paper diameter sensor 23 is a laser reflection type sensor, and is not limited to this embodiment as long as it has an equivalent function. The remaining of the roll paper 1 is caused by the mechanical lever coming into contact with the outer periphery of the roll paper. A form for detecting the quantity is also equivalent.

  In the present invention, the roll paper diameter sensor 23 detects the outer diameter of the roll paper 1 to be loaded, thereby setting the optimum conveyance speed of the line feed roller 10 and achieving the image forming operation.

  The relationship between the embodiment of the present invention shown in FIGS. 5 and 6 and the claims is as follows.

  The roll paper 1, the roll support guide 2, and the paper feed guide 24 are paper feed units according to claims.

  The carriage motor 3, the pulley 4, the timing belt 5, the carriage 6, the ink cartridge 7, the recording head 8, and the guide 9 are image forming units according to claims.

  The rotary cutter 15 and the cutter lower guide 16 are cutter units described in claims.

  The paper discharge guide 17 is a paper discharge unit described in the claims.

  The line feed roller 10 and the pinch roller 12 are a pair of rollers according to the claims, and the other including the encoder film 11, the paper feed motor 13, and the platen 14 is a transport unit according to the claims. The input panel 18 is input means described in claims.

  An electrical device such as a CPU, a memory, and a motor driver for controlling the entire operation of the printer is an electrical board 25, and the storage means described in the claims is also disposed here.

  The roll paper diameter sensor 23 is a roll paper diameter detection means described in the claims.

  The above is the description of the image forming apparatus configuration.

[Description of operation]
First Embodiment The operation of the image forming apparatus according to the present invention will be described below.

  Even when the line feed roller 10 that requires high-precision sheet material conveyance has a simple printer configuration that directly pulls out the sheet material from the roll paper 1, the moment that occurs when the line feed roller 10 starts moving, that is, when the sheet material is pulled out. Highly accurate sheet material conveyance can be achieved without causing slippage.

  FIG. 2 is a diagram showing the line feed roller and carriage operation during the image forming operation of the present invention. The upper part shows the operation speed of the carriage 6 and the lower part shows the conveyance speed of the line feed roller 10 at the same time. .

  After the line feed roller 10 conveys a predetermined amount of sheet material with the sheet material conveyance speed as a target value VL, the carriage 6 sequentially performs reciprocation in the forward or backward direction along the guide 9 as the operation speed Vcr. This is performed while the roller 10 is stopped.

  By repeating the above operation n times, image formation for one page is achieved, and the page length is generally the sum of the areas ln (n = 1, 2,..., N) of one section of the line feed conveyance speed diagram Σln ( n = 1,2, ..., n).

  The above operation is the operation of a carriage and a line feed roller of a general ink jet printer, but the feature of the present invention is that the target feed speed VL of the line feed roller described can be changed according to the remaining amount of roll paper loaded. It is to become.

  FIG. 1 is a graph showing the remaining roll paper and the line feed roller target speed, which is a feature of the present invention. The target set value of VL is described with respect to the remaining roll paper.

  In the printer of the present invention, as shown in FIG. 6, a long roll paper having a maximum diameter φDmax can be loaded with respect to a standard length roll paper.

  In FIG. 1, in the roll paper (section (I)) where the roll paper length forming the standard roll diameter is 20 m (section (I)), when the roll paper length forming the maximum loadable diameter φDmax is 50 m (section (II) The relationship between the roll paper remaining amount L and the line feed target transport speed VL is described.

In the case of a standard roll, the line feed roller 10 can achieve highly accurate sheet material conveyance at a target conveyance speed VL = v1 (P1 → P0). (Section (I))
In the case of a large-diameter roll whose sheet material conveyance load is larger than the standard roll, the line feed roller 10 is driven at a low speed with the target conveyance speed VL = v2 when the remaining roll L is 50 to 20 [m] (section (II)). (P3 → P2) When the remaining amount L of roll paper is less than 20 [m], which is the same as that of the standard roll, the drive is switched to the target transport speed VL = v1.

  The difference in the conveyance speed diagram ln for one time of the line feed roller 10 in the state where the remaining amount L of the roll paper is in the section (I) and the section (II) is shown in FIG.

  When the roll paper remaining amount is a large-diameter roll length in the section (II), the speed diagram of the line feed roller 10 is ln (abc-d) and the remaining roll paper is the section (I). When the roll length is standard, the line feed roller 10 is driven at a speed of ln ′ (a−b′−c′−d ′).

  Here, the areas ln and ln ′ represent the sheet material conveyance distance of the roll paper 1 by the line feed roller 10, and the area ln = area ln ′ is maintained.

  This is because a single roll paper according to the size of the roll diameter keeps the carry amount per roll by the line feed roller 10 constant and changes the throughput per time, thereby increasing the roll paper feed rate. Large diameter roll paper can be conveyed while maintaining accuracy.

  The roll paper remaining amount L is sequentially calculated by the roll paper diameter sensor 23. If the roll paper remaining amount L <20 [m], which causes the speed switching during image formation, is calculated, the speed switching is performed after the in-process page. .

  By this operation, image formation can be performed without causing color unevenness caused by speed switching in the page.

  The configuration having the roll paper diameter sensor 23 is the image forming apparatus according to claim 3.

  As described above, even when a large-diameter roll paper having a larger pulling load of the roll paper 1 is mounted on the line feed roller 10, continuous image formation for a longer time is achieved without causing image deterioration due to slippage of the sheet material. It becomes possible.

  Then, the number of replacements of the roll paper 1 is reduced to achieve maintenance-free.

Second Embodiment It is also possible to use the line feed roller velocity diagram of FIG.

  A large-diameter roll suitable for changing the target conveyance speed of the line feed roller 10 from P2 → P1 → P0 is easy to ensure the grip force of the line feed roller 10 stably, and the weight (basis weight) of the sheet material is It is a large sheet material and is experimentally suitable for roll paper based on cardboard coated paper / film systems.

  A large-diameter roll suitable for changing the target conveying speed of the line feed roller 10 from P2 to P0 is suitable for a sheet material in which the grip force of the line feed roller 10 is likely to vary.

  Experimentally, the thickness of the sheet material such as Japanese paper varies, and the mechanical rigidity of the sheet material is small, which is suitable for roll paper made of a soft material.

  The large-diameter roll suitable for changing the target conveyance speed of the line feed roller 10 in FIG. 1 from P3 → P2 → P1 → P0 is easy to ensure the grip force of the line feed roller 10 stably, and the weight of the sheet material Suitable for sheet materials with a relatively small basis weight.

  Experimentally suitable for roll paper based on thin coated paper and plain paper.

  Whether the target conveying speed of the line feed roller 10 should be set in any of the speed diagrams shown in FIG. 1 or FIG. 4 is experimentally set in consideration of environmental characteristics such as the temperature / humidity of the roll paper and the friction coefficient. Is desirable.

  The image forming apparatus according to claim 2, wherein the printer can selectively set a conveyance speed setting of the line feed roller 10 corresponding to a large-diameter roll paper optimum for a paper type.

  In the image forming apparatus configuration, the roll paper target transport speed of the line feed roller 10 is stored in the printer for each paper type, and the speed setting shown in FIG. 1 or FIG. 4 is stored in the printer. The paper type and remaining amount information of the roll paper 1 to be loaded are input.

  FIG. 7 shows an image forming apparatus having roll paper weight detection means of the present invention, and FIG. 8 is a graph showing the remaining roll paper having roll paper weight detection means and the target line feed roller speed.

  In the image forming apparatus of FIG. 7, reference numeral 26 denotes a roll paper weight detection unit, and 27 denotes a rotation shaft for the roll support guide 2 to make a rotational movement with respect to the image forming apparatus main body. The flag 28 and the roll paper diameter sensor 23 are integrated with the roll support guide 2.

  The roll support guide 2 is always applied with a rotational force in the direction of τ around the rotation shaft 27 by a spring (not shown).

  A state in which the large-diameter roll paper 1 is loaded on the roll support guide 2 is indicated by a broken line. When the large-diameter roll paper 1 is consumed and becomes a predetermined weight or less, the roll support guide 2 is rotated by θ by the rotational force τ applied around the rotation shaft 27.

  In conjunction with the movement of the roll support guide 2, the flag 28 also moves by a predetermined angle. Then, the roll paper weight detection means 26 for detecting the movement of the flag 28 changes its state from ON to OFF.

  In the image forming apparatus, the line feed target transport speed VL and the roll paper remaining amount L are set in accordance with a state change from ON to OFF of the roll paper weight detection means 26. The relationship with is as shown in FIG.

  Take a roll paper with a total length of 50m as an example. When the roll paper weight detection means 26 is switched from ON (section (II)) to OFF (section (I)) (P2 → P1), the conveyance speed VL is characterized by switching from V2 to V1.

  This configuration is an example of the image forming apparatus according to claim 4, and the line feed of V 1 to V 2 is determined according to the roll diameter information from the roll paper diameter sensor 23 and the ON / OFF information of the roll paper weight detection means 26. A configuration for calculating the target conveyance speed is also included.

Roll paper remaining amount and line feed roller target speed diagram of the present invention Line feed roller and carriage operation diagram during image forming operation of the present invention Roll paper remaining amount and line feed roller unit operation speed diagram of the present invention Other roll paper remaining amount and line feed roller speed diagram of the present invention Image forming apparatus of the present invention Cross-sectional view of the image forming apparatus of the present invention Image forming apparatus having roll paper weight detecting means of the present invention Roll paper remaining amount and line feed roller target speed diagram having roll paper weight detection means of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Roll paper 6 Carriage 10 Line feed roller 13 Paper feed motor 14 Platen 15 Rotary cutter 17 Paper discharge guide 18 Input panel 23 Roll paper diameter sensor 26 Roll paper weight detection means

Claims (5)

A sheet feeding unit that accommodates roll paper wound with a long sheet, an image forming unit that forms an image on the surface of the long sheet conveyed from the sheet feeding unit, and a long sheet on which the image has been formed is cut. A sheet material conveyance path in which a cutter unit and a paper discharge unit are sequentially arranged in the sheet material conveyance direction, and a long sheet of roll paper stored in the sheet feeding unit is fed while being pulled out to the image forming unit. An image forming apparatus comprising: a pair of rollers configured to have a conveying unit disposed between a paper feeding unit and the image forming unit so as to face the image forming unit;
An image forming apparatus, wherein a conveying speed of the long sheet in an image forming operation for forming an image is switched at least once during one roll length.   The image forming operation is performed by sequentially repeating the intermittent conveyance of the long sheet by the roller pair, and the maximum conveyance speed for each intermittent conveyance is switched at least once in the middle of one roll length. The image forming apparatus according to claim 1.   Input means for inputting the outer diameter of the roll paper stored in the paper feeding unit and paper type information, and storage means for storing the outer diameter of the roll paper, the roll paper consumption, and the maximum speed for each paper type. The image forming apparatus according to claim 2, wherein a maximum speed for each intermittent conveyance is set for each image forming page in accordance with the outer diameter of the roll paper, the consumption of the roll paper, and the paper type information. .   Roll paper diameter detecting means for detecting the outer diameter of the roll paper is provided, and the maximum speed for each intermittent conveyance is set for each image forming page in accordance with an output signal of the roll paper diameter detecting means. The image forming apparatus according to claim 2.   A roll paper weight detection unit for detecting the weight of the roll paper is provided, and a maximum speed for each intermittent conveyance is set for each image forming page according to an output signal of the roll paper weight detection unit. The image forming apparatus according to claim 2.

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