Display device and image forming device

Abstract

To provide a display device and an image formation device that prevent deterioration in operability and convenience caused by displaying a keyboard superimposed on an operation screen.SOLUTION: An image formation device 1 includes: a display unit 473 with a touch panel function; a display control unit 101 that controls display of the display unit 473, causes the display unit 473 to display an operation screen that has a character input column and is subject to scroll display, and further displays a keyboard read out when entering a character in the character input column while superimposed on the operation screen; and an operation unit 47 that accepts an instruction based on a touch operation on the display unit 473 detected by the touch panel function and also accepts input of the character via the keyboard. The display control unit 101 displays a scroll bar for accepting a scroll instruction for scroll-displaying the operation screen whose display range is narrowed by superimposing the keyboard within the narrowed display range without overlapping the keyboard.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a display device and an image forming apparatus having a touch panel function. [Background technology]

[0002] In recent years, electronic devices equipped with touch panel functions have become much more functional, and as a result, the display of the operation screen has become more complex. Also, when the operation screen is displayed, if there are many operation contents and the display cannot be displayed in a set area, a scroll display may be adopted (for example, see Patent Documents 1 and 2 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-090248 A [Patent Document 2] JP 2014-074981 A Summary of the Invention [Problem to be solved by the invention]

[0004] Fig. 3(A) is a diagram showing an example of an operation screen displayed on a display unit constituting an image forming apparatus such as a multifunction peripheral. Display screen G1 shown in Fig. 3(A) has a number of display areas A1 to A6. Character input fields SP1 to SP4 are displayed in display area A4, but as the display does not fit within the area, a scroll bar 3 is also displayed. Scroll bar 3 includes an upward arrow 31, a downward arrow 32, and a knob 33.

[0005] Some image forming devices have a function of superimposing a keyboard KB1 on the display screen G1 as shown in Fig. 6 in order to accept character input from the user into the character input field SP1 when the character input field SP1 is touched in the display state shown in Fig. 3(A). The user can input characters into the character input field SP1 using the keyboard KB1 and the touch panel function.

[0006] However, as shown in FIG. 6, when the keyboard KB1 is superimposed on the display screen G1, the character input fields SP3 and SP4 are hidden by the keyboard KB1, and characters cannot be input into the character input fields SP3 and SP4.

[0007] In addition, the downward arrow 32 of the scroll bar 3 is also hidden, so that an instruction to scroll up cannot be received from the user. When the keyboard is superimposed on the operation screen in this way, operability and convenience are significantly reduced.

[0008] The present invention has been made in consideration of the above circumstances, and has an object to prevent a decrease in operability and convenience caused by a keyboard being superimposed on an operation screen. [Means for solving the problem]

[0009] A display device according to one aspect of the present invention comprises a display unit having a touch panel function, a display control unit which controls the display of the display unit and causes an operation screen having a character input field and which is subject to scrolling to be displayed on the display unit, and further causes a keyboard which is read out when characters are entered into the character input field to be superimposed on the operation screen, and an operation unit which accepts instructions based on touch operations on the display unit detected by the touch panel function and accepts character input via the keyboard, and the display control unit displays a scroll bar for accepting scroll instructions for scrolling the operation screen, the display range of which has been narrowed by the superimposed display of the keyboard, within the narrowed display range without overlapping the keyboard.

[0010] An image forming apparatus according to one aspect of the present invention includes the above-described display device and an image forming section that forms an image on a recording medium. Effect of the Invention

[0011] According to the present invention, when a keyboard is superimposed on an operation screen, a scroll bar is displayed on the operation screen, so that an image of the operation screen hidden by the keyboard can be displayed without hiding the keyboard. Also, since the scroll bar is displayed in an empty area that does not overlap with the keyboard, keyboard operation is not hindered by the scroll bar. As a result, even if a keyboard is superimposed on the operation screen, a decrease in operability and convenience due to the superimposed display is prevented. [Brief description of the drawings]

[0012] [Figure 1] 1 is a perspective view showing an external appearance of an image forming apparatus which is an embodiment of a display device according to the present invention. [Diagram 2] 1 is a functional block diagram illustrating a schematic internal configuration of an image forming apparatus. [Diagram 3] 5A and 5B are diagrams showing an example of a display screen displayed on a display unit. [Figure 4] FIG. 2 is a diagram showing an entire image to be displayed in a display area. [Diagram 5] FIG. 4 is a diagram showing an example of a display screen displayed on a display unit. [Figure 6] FIG. 13 is a diagram showing, as a reference example, an example of a state in which a keyboard is superimposed on an operation screen. [Figure 7] 5A and 5B are diagrams showing an example of an operation screen displayed on a display unit. [Figure 8] FIG. 13 is a diagram showing, as a reference example, an example of a state in which a keyboard is superimposed on an operation screen. [Figure 9] 5A and 5B are diagrams showing an example of a display screen displayed on a display unit. [Figure 10]5 is a flowchart showing a first embodiment of display control by the image forming apparatus. [Figure 11] FIG. 13 is a diagram showing an example of a keyboard superimposed on the operation screen. [Figure 12] 5A and 5B are diagrams showing an example of a display screen displayed on a display unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] A display device and an image forming device according to an embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a perspective view showing the appearance of an image forming device including a display device according to an embodiment of the present invention. Fig. 2 is a functional block diagram showing the main internal configuration of the image forming device.

[0014] The image forming device 1 is a multifunction device having multiple functions, such as a copy function, a printer function, a scanner function, and a facsimile function, and is configured to include a device main body 11, a control unit 10, a document feeding section 6, a document reading section 5, an image forming section 12, a fixing section 13, a paper feeding section 14, an operation section 47, and a memory device 8.

[0015] The document feeder 6 is configured to be openable and closable by a hinge or the like (not shown) on the top surface of the document reading unit 5, and functions as a document pressing cover when reading a document placed on a platen glass (not shown). The document feeder 6 is an ADF (Auto Document Feeder) and includes a document placement tray 61, and feeds documents placed on the document placement tray 61 to the document reading unit 5 one sheet at a time.

[0016] The document feed unit 6 is configured to be able to mechanically invert the document from front to back after the document reading unit 5 has read the image on the front side of the document, and feed the document again to the document reading unit 5. This allows the document reading unit 5 to read both sides of the document.

[0017] A description will be given of a case where a document reading operation is performed by the image forming apparatus 1. The document reading unit 5 optically reads an image of a document supplied to the document reading unit 5 by the document feeding unit 6 or a document placed on the platen glass, and generates image data. The image data generated by the document reading unit 5 is stored in an image memory or the like (not shown).

[0018] The following describes an image forming operation performed by the image forming apparatus 1. Based on image data generated by a document reading operation, image data stored in an image memory or the like, image data received from a computer connected via a network, and the like, the image forming unit 12 forms a toner image on a recording paper as a recording medium fed from a paper feed unit 14.

[0019] The fixing unit 13 applies heat and pressure to the recording paper on which the toner image has been formed by the image forming unit 12, thereby fixing the toner image to the recording paper. The recording paper that has been subjected to the fixing process is discharged onto a discharge tray 151. The paper supply unit 14 includes a plurality of paper supply cassettes 141.

[0020] The operation unit 47 receives instructions, such as an instruction to execute an image forming operation, from an operator regarding various operations and processes that can be executed by the image forming apparatus 1. The operation unit 47 includes a display unit 473 that displays operation guides and the like for the operator. The operation unit 47 also receives user instructions, detected by a touch panel function based on a touch operation on the display unit 473, via a touch panel included in the display unit 473. The operation unit 47 also receives character input via a keyboard, which will be described later, that is displayed on the display unit 473.

[0021] The display unit 473 is composed of an LCD (Liquid Crystal Display) or the like. The display unit 473 is equipped with a touch panel. When the operator touches a button or key displayed on the screen, the touch panel receives an instruction associated with the touched position.

[0022] The storage device 8 is a large-capacity storage device such as a hard disk drive (HDD) or a solid state drive (SSD), and stores various control programs and the like.

[0023] The control unit 10 includes a processor, a RAM (Random Access Memory), a ROM (Read Only Memory), and a dedicated hardware circuit. The processor is, for example, a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), or an MPU (Micro Processing Unit). The control unit 10 includes a control unit 100 and a display control unit 101.

[0024] The control unit 10 functions as a control unit 100 and a display control unit 101 by the operation of the processor in accordance with a control program stored in the storage device 8. However, the control unit 100 and the like can also be configured by hardware circuits, without relying on the operation of the control unit 10 in accordance with a control program. The same applies to each embodiment below unless otherwise stated.

[0025] The control unit 100 is responsible for controlling the overall operation of the image forming apparatus 1. The control unit 100 is connected to the document feed unit 6, the document reading unit 5, the image forming unit 12, the fixing unit 13, the paper feeding unit 14, the operation unit 47, and the storage device 8, and performs drive control of each of these units. For example, the control unit 100 controls the operation of the image forming unit 12, etc., to form the document image obtained by reading by the document reading unit 5 on recording paper as a recording medium.

[0026] The display control unit 101 performs display control of the display unit 473. For example, the display control unit 101 causes the display unit 473 to display an operation screen in accordance with an instruction input from the user via the operation unit 47.

[0027] Fig. 3(A) or 3(B) is a diagram showing an example of a display screen that the display control unit 101 causes the display unit 473 to display. The display screen G1 shown in Fig. 3(A) or 3(B) has a plurality of display areas A1 to A6. An operation screen D1 is displayed in a display area A4 that is a part of the display screen G1. A scroll bar 3 is displayed on the operation screen D1 displayed in the display area A4 to receive a scroll instruction for scrolling the image of the operation screen D1 to be displayed in the display area A4.

[0028] Fig. 4 is a diagram showing the entire image of operation screen D1. As shown in Fig. 4, display image M1 includes character input fields SP1 to SP5 (for example, text boxes) into which characters are input, and operation buttons B1 to B3.

[0029] 3(A), scroll bar 3 includes an upward arrow 31 for scrolling down, a downward arrow 32 for scrolling up, and a knob 33 indicating the position of the portion displayed in the display range of display area A4 in the entirety (display image M1 shown in FIG. 4). The position and size of knob 33 shown in FIG. 3(A) indicate that the portion currently displayed in display area A4 is about two-thirds of the display image M1 from the top in this example. Note that upward arrow 31 and downward arrow 32 are examples of the first direction operation button and second direction operation button in the claims.

[0030] Fig. 5 is a diagram showing another example of a display screen that the display control unit 101 causes the display unit 473 to display. The display screen G2 shown in Fig. 5 has a plurality of display areas A1 to A3, A5 to A8. The display area A8 displays an operation screen D2. The operation screen D2 displays character input fields SP6, SP7 into which only numbers are input, and operation buttons B4 to B7 representing "+" or "-" symbols for increasing or decreasing the numbers input into the character input fields SP6, SP7.

[0031] Here, when the operation unit 47 receives a character input operation into a character input field while the display screens G1 and G2 are being displayed, the display control unit 101 reads out an image of a keyboard (hereinafter simply referred to as the keyboard) from the storage device 8 and superimposes the read-out keyboard on the operation screens D1 and D2 on the display screens G1 and G2.

[0032] The display control unit 101 further scrolls and displays the images of the operation screens D1 and D2 to be displayed in the display area whose display range has been narrowed by the superimposed display of the keyboard. The display control unit 101 displays scroll bars in a free area in the display range that does not overlap with the keyboard, for receiving a scroll instruction for scrolling and for indicating the position of the operation screens D1 and D2 portions displayed in the narrowed display range in the entire images of the operation screens D1 and D2.

[0033] For example, when the operation unit 47 accepts a touch operation on the character input field SP1 shown in Fig. 3(A) via the touch panel, the display control unit 101 reads out a keyboard KB1 (e.g., a QWERTY keyboard) from the storage device 8 and displays the read out keyboard KB1 superimposed on the display screen G1. Fig. 6 is a diagram showing, as a reference example, an example of a state in which a keyboard is superimposed on the operation screen D1 on the display screen G1.

[0034] 7A, the display control unit 101 further displays the scroll bar 30 in a free area that does not overlap with the keyboard KB1 in the operation screen D1 displayed in the display area A4 whose display range has been narrowed. The scroll bar 30 is configured to include an upward arrow 31, a downward arrow 32, and a knob 33, similar to the scroll bar 3.

[0035] In addition, if the scroll bar 3 is displayed in the display area of ​​the operation screen D1 before the keyboard KB1 is superimposed on the operation screen D1, the display control unit 101 will shorten the length of the scroll bar 3 and display it in the narrowed display range.

[0036] Figure 7(B) shows a state in which, in the display state shown in Figure 7(A), the operation unit 47 accepts an operation on the downward arrow 32 via the touch panel, and the image of the operation screen D1 to be displayed in the display area A4 is scrolled up by the display control unit 101.

[0037] Furthermore, when the operation unit 47 receives a touch operation on the character input field SP6 shown in Fig. 5 via the touch panel, the display control unit 101 reads out a keyboard KB2 (a numeric keypad) and displays the read out keyboard KB2 superimposed on the display screen G2. Fig. 8 is a diagram showing, as a reference example, an example of a state in which a keyboard is superimposed on the operation screen D2 on the display screen G2. The display control unit 101 reads out a numeric keypad instead of a QWERTY keyboard because the only characters that the character input field SP6 can accept are "numbers."

[0038] The display control unit 101 further displays the scroll bar 30 in a free area that does not overlap with the keyboard KB2 in the operation diagram D2 displayed in the display area A8, as shown in FIG. 9(A).

[0039] Figure 9(B) shows a state in which, in the display state shown in Figure 9(A), the operation unit 47 accepts an operation on the downward arrow 32 via the touch panel, and the image of the operation screen D2 to be displayed in the display area A8 is scrolled up by the display control unit 101.

[0040] Next, a first embodiment of the above-mentioned display control by the image forming apparatus 1 will be described with reference to the flowchart shown in Fig. 10. Note that the display control unit 101 performs this display control when the operation unit 47 accepts a request from the user to input characters into a character input field.

[0041] When operation unit 47 accepts a user request for character input into a character input field, display control unit 101 determines whether the character input field accepts only numbers as input (S1).

[0042] When the display control unit 101 determines that the character input field accepts input of more than just numbers (NO in S1), it reads out keyboard KB1 (QWERTY keyboard) from the storage device 8 (S2). On the other hand, when the display control unit 101 determines that the character input field accepts input of only numbers (YES in S1), it reads out keyboard KB2 (numeric keypad) from the storage device 8 (S3).

[0043] The display control unit 101 displays the read keyboard superimposed on the display screen (S4). For example, as shown in Fig. 7(A) or Fig. 9(A), the display control unit 101 displays the keyboards KB1 and KB2 superimposed on the display screens G1 and G2. For example, the display control unit 101 makes the keyboards KB1 and KB2 appear so as to rise from the lower ends of the display screens G1 and G2.

[0044] Here, the display control unit 101 judges whether the keyboards KB1, KB2 are superimposed on the operation screens D1, D2 when the keyboards KB1, KB2 are displayed (S5). Note that the display control unit 101 judges whether the keyboards KB1, KB2 are superimposed on the operation screens D1, D2 based on the coordinates indicating the display area of ​​the operation screens D1, D2 on the display screens G1, G2 and the coordinates of the display area in which the keyboards KB1, KB2 are displayed.

[0045] When the display control unit 101 determines that the keyboards KB1 and KB2 are superimposed on the operation screens D1 and D2 (YES in S5), it subtracts the length of the keyboards KB1 and KB2 in the scroll direction from the length of the display areas A4 and A8 before the keyboards KB1 and KB2 are displayed, thereby calculating the length of the display areas A4 and A8 in the scroll direction after the keyboards KB1 and KB2 are displayed as the size of the display range in which the operation screens D1 and D2 can be displayed after the keyboards KB1 and KB2 are displayed (S6).Furthermore, the display control unit 101 sets the length of the scroll bar 30 according to the calculated size of the display range (S7).

[0046] Then, the display control unit 101 displays the scroll bar 30, the length of which has been set in this manner, on the operation screens D1 and D2 within the display range narrowed as described above, without overlapping with the keyboards KB1 and KB2 (S9).

[0047] In other words, when the display control unit 101 superimposes the keyboards KB1 and KB2 on the operation screens D1 and D2 while a scroll bar is being displayed on the operation screens D1 and D2, the length of the scroll bar is shortened to a length that fits within the narrowed display range as described above, and the scroll bar is displayed as scroll bar 30.

[0048] On the other hand, when the display control unit 101 superimposes the keyboards KB1 and KB2 on the operation screens D1 and D2 from a state in which the scroll bar 30 is not displayed on the operation screens D1 and D2, the scroll bar 30, which is set to a length that fits within the narrowed display range as described above, is displayed on the operation screens D1 and D2 within that display range.

[0049] Since the length of the keyboard KB2 in the scroll direction is shorter than that of the keyboard KB1, the display control unit 101 displays the scroll bar 30 by making the length of the scroll direction in the display range longer when the keyboard KB2 is superimposed.

[0050] Next, the display control unit 101 judges whether the operation unit 47 has received a user operation on the operation buttons E1, E2 (see FIG. 7 and FIG. 9) labeled "Enter" displayed on the keyboard (S10). The operation buttons are images for receiving an instruction from the user to confirm the input characters.

[0051] When the display control unit 101 determines that the operation unit 47 has received a user operation on the operation buttons E1 and E2 via the touch panel (YES in S10), it erases the scroll bar 30 and the keyboards KB1 and KB2 from the operation screen, and returns the display screens G1 and G2 to their original state before the keyboards KB1 and KB2 were displayed (S11). After this, the process ends.

[0052] In addition, in S5, when the display control unit 101 determines that the keyboards KB1 and KB2 are not superimposed on the operation screens D1 and D2 (NO in S5), the display control unit 101 maintains the display of the operation screens D1 and D2 as is without displaying the scroll bar 30. After that, the process ends.

[0053] According to the first embodiment, when the keyboards KB1, KB2 are superimposed on the operation screens D1, D2, the scroll bar 30 is displayed on the operation screens D1, D2, so that the image hidden by the keyboards KB1, KB2 can be displayed without hiding the keyboards KB1, KB2. Also, the user can grasp the position of the operation screens D1, D2 displayed in the display range in the whole from the display form of the scroll bar 30.

[0054] In addition, since the scroll bar 30 is displayed in an empty area that does not overlap the keyboards KB1 and KB2, the operation of the keyboards KB1 and KB2 is not hindered by the scroll bar 30. This makes it possible to prevent a decrease in operability and convenience caused by the keyboards KB1 and KB2 being superimposed on the operation screen.

[0055] In the first embodiment, the length of the scroll bar 30 is calculated and set each time. However, since the types of operation screens and keyboards on which character input fields are displayed are limited, the display control unit 101 may prepare in advance the length of the scroll bar 30 according to the combination of the operation screen and keyboard to be displayed based on the sizes of the operation screen and keyboard, rather than calculating and setting the length of the scroll bar 30 each time.

[0056] The keyboard superimposed on the operation screen is not limited to a QWERTY keyboard or a numeric keypad. As another keyboard, for example, a keyboard KB3 (50-sound keyboard) in which the 50 Hiragana sounds are arranged in order as shown in FIG. 11 may be used.

[0057] The user can grasp the proportion of the size that the operation screen portion displayed in the above-mentioned display range occupies in the entire image of the operation screen from the size of knob 33 of scroll bar 30. For example, as shown in Fig. 7(A) or 7(B), the user can grasp from the size of knob 33 that the operation screen portion displayed in the display range of display area A4 is about 30% of the entire image of the operation screen (display image M1 shown in Fig. 4).

[0058] On the other hand, it may not be easy to grasp the proportion of the size of the operation screen portion displayed in the display range to the entire image of the operation screen from the size of the knob 33. Therefore, as another embodiment, the display control unit 101 may set the length of the scroll bar 30 to be displayed on the operation screen within the display range to a length corresponding to the entire length of the image of the operation screen. That is, the display control unit 101 sets the length of the scroll bar 30 to a larger value as the entire length of the image of the operation screen to be displayed in the display range becomes longer. This allows the user to grasp the size of the other parts of the operation screen that appear by the scroll display, and ultimately the size of the entire image of the operation screen, from the length of the scroll bar 30.

[0059] Next, a description will be given of a second embodiment of the above-mentioned display control by the image forming apparatus 1. In the second embodiment, the display control unit 101 further performs display control such that, when a keyboard is displayed superimposed on the operation screen, if the keyboard can be displayed while keeping the character input field in the operation screen displayed without being hidden, the scroll bar 30 is not displayed.

[0060] That is, the display control unit 101 judges whether or not the character input field will be hidden by superimposing the keyboard on the operation screen, and if it judges that the character input field will be hidden, it displays the scroll bar 30, but if it judges that the character input field will not be hidden, it does not display the scroll bar 30. For example, the display control unit 101 judges whether or not the keyboard is being displayed superimposed on the position of the character input field based on the coordinates indicating the display area of ​​the character input field on the displayed operation screen and the coordinates of the display area in which the keyboard is to be displayed.

[0061] Fig. 12(A) is a diagram showing an example of an operation screen on which a keyboard is not displayed. The display screen G3 shown in Fig. 12(A) has display areas A1 to A6. In the display area A4, a character input field SP8 and operation buttons B8 to B12 are displayed.

[0062] When the operation unit 47 accepts a character input operation into the character input field SP8 via the touch panel, the display control unit 101 reads out the keyboard KB1 from the storage device 8 and displays the read out keyboard KB1 superimposed on the operation screen D3.

[0063] Even if the keyboard KB1 is superimposed on the operation screen D3 and the display range of the operation screen D3 in the display area A4 becomes narrower, only the operation buttons B11 and B12 are hidden, and the character input field is not hidden. In this case, as shown in FIG. 12(B), the display control unit 101 does not display the scroll bar 30.

[0064] According to the second embodiment, when the absence of the scroll bar 30 does not impede operation, the scroll bar 30 is not displayed, thereby further improving operability and convenience when a keyboard is superimposed on the operation screen.

[0065] Furthermore, when the keyboard is displayed superimposed on the operation screen, the display range of the operation screen becomes significantly narrower, and it may not be easy to display the scroll bar 30 with good visibility. For example, when the display range of the operation screen is significantly narrower, a situation may arise in which the upward arrow 31 and the downward arrow 32 of the scroll bar 30 must be displayed so as to almost overlap each other.

[0066] Therefore, as another embodiment, the display control unit 101 judges whether the length H in the scroll direction of the operation screen displayed in the above display range is equal to or greater than a predetermined value TH required for displaying the upward arrow 31 and the downward arrow 32, and when it judges that the length H is less than the value TH, it displays a scroll bar 30 that includes only either the upward arrow 31 or the downward arrow 32, or neither of them.

[0067] Furthermore, when the display control unit 101 determines that the length H is less than the value TH, it may display a part or all of the scroll bar 30 superimposed on the keyboard, rather than not displaying the upward arrow 31 and the downward arrow 32. That is, the display control unit 101 performs the display control of (i) displaying the upward arrow 31 or the downward arrow 32 superimposed on the keyboard, or (ii) displaying the entire scroll bar 30 including the upward arrow 31 and the downward arrow 32 superimposed on the keyboard.

[0068] In this case, the keyboard is laid out in such a way that an area is secured in which all or part of the scroll bar 30 can be placed, and the arrangement of each key is determined accordingly. Alternatively, when the scroll bar 30 is displayed overlapping the keyboard, the display control unit 101 changes the layout of the keyboard to secure an area in which all or part of the scroll bar 30 can be placed.

[0069] The present invention is not limited to the configuration of the above embodiment, and various modifications are possible. In the above embodiment, one embodiment of the display device according to the present invention is shown as an image forming device, but this is only one example, and the display device according to the present invention may be provided in other electronic devices, such as medical equipment, car navigation systems, or ticket vending machines.

[0070] In addition, in the above embodiment, the configuration and processing shown in the above embodiment using FIGS. 1 to 12 are merely one embodiment of the present invention, and it is not intended that the present invention be limited to these configurations and processing. [Explanation of symbols]

[0071] 1. Image forming device 12 Image forming section 47 Operation section 100 Control section 101 Display control unit 473 Display section

Claims

1. A display unit having a touch panel function; a display control unit that performs display control on the display unit, causes an operation screen having a character input field and being subject to scroll display to be displayed on the display unit, and further causes a keyboard that is read out when characters are input into the character input field to be superimposed on the operation screen; an operation unit that receives an instruction based on a touch operation on the display unit detected by the touch panel function and receives character input via the keyboard, the display control unit displays a scroll bar for receiving a scroll instruction for scrolling the operation screen, the display range of which has been narrowed by the superimposed display of the keyboard, within the narrowed display range without overlapping with the keyboard; The display control unit sets the length of the scroll bar to be displayed in the narrowed display range to a length corresponding to the length of the entire image of the operation screen to be scrolled into the narrowed display range.

2. A display unit having a touch panel function; a display control unit that performs display control on the display unit, causes an operation screen having a character input field and being subject to scroll display to be displayed on the display unit, and further causes a keyboard that is read out when characters are input into the character input field to be superimposed on the operation screen; an operation unit that receives an instruction based on a touch operation on the display unit detected by the touch panel function and receives character input via the keyboard, the display control unit displays a scroll bar for receiving a scroll instruction for scrolling the operation screen, the display range of which has been narrowed by the superimposed display of the keyboard, within the narrowed display range without overlapping with the keyboard; the scroll bar includes a first directional operation button for accepting a scroll instruction in one direction on the operation screen, and a second directional operation button for accepting a scroll instruction in a direction opposite to the one direction, A display device in which, when the display control unit determines that the size of the narrowed display range in the scroll direction does not meet a predetermined value required for displaying the first directional operation button and the second directional operation button, the display control unit displays the scroll bar in the narrowed display range, the scroll bar including only the first directional operation button or the second directional operation button, or including neither.

3. A display unit having a touch panel function; a display control unit that performs display control on the display unit, causes an operation screen having a character input field and being subject to scroll display to be displayed on the display unit, and further causes a keyboard that is read out when characters are input into the character input field to be superimposed on the operation screen; an operation unit that receives an instruction based on a touch operation on the display unit detected by the touch panel function and receives character input via the keyboard, the display control unit displays a scroll bar for receiving a scroll instruction for scrolling the operation screen whose display range has been narrowed by the superimposed display of the keyboard, the scroll bar includes a first directional operation button for accepting a scroll instruction in one direction on the operation screen, and a second directional operation button for accepting a scroll instruction in a direction opposite to the one direction, When the display control unit determines that the size of the narrowed display range in the scroll direction does not meet a predetermined value required for displaying the first directional operation button and the second directional operation button, the display device displays part or all of the scroll bar superimposed on the keyboard that is displayed superimposed on the operation screen.

4. A display device according to any one of claims 1 to 3, An image forming apparatus comprising: an image forming unit that forms an image on a recording medium.

Images